Labelling machine

Abstract

There is disclosed a labelling machine (300). The labelling machine comprises a supply spool support (10) for supporting a supply spool (16) comprising label stock (18). The label stock comprises a web and a plurality of labels attached to the web. The labelling machine further comprises a take-up spool support (12) configured to take up a portion of the web. The labelling machine further comprises a motor (14). The motor is configured to advance the web along a web path (20) from the supply spool support towards the take up spool support. The labelling machine further comprises a labelling peel beak (30). The labelling peel beak is located along the web path. The labelling peel beak is configured to peel the labels from the web as the web passes the labelling peel beak. The labelling machine further comprises a movable member (50). The movable member is configured to contact a portion of the web and define a portion of the web path between the labelling peel beak and the take-up spool support. Movement of the moveable member changes a length of the web path. A position of the movable member is controllable via an actuator (55). The labelling machine further comprises a controller (88, 92) configured to control the actuator to adjust the position of the movable member, and control a position of the motor.

Description

[0001]Machine Field of Invention The present invention relates to a labelling machine, and to a method of operating a labelling machine and / or applying a label to a target item. Background Labelling machines typically use label stock comprising a web and a plurality of labels attached to the web and which are separable from the web. Such machines are sometimes referred to as “roll-fed self-adhesive labelling machines”. A label stock comprising a web carrying labels is usually manufactured and supplied as a wound roll (hereinafter referred to as a spool). For a given spool, all the labels are typically the same size, within manufacturing tolerances. However, in some instances, this is not the case. Labels are commonly used to display information relating to an article and are commonly disposed on the article such that the information is easily readable either manually or automatically. Such labels may, for example, display product information, barcodes, stock information or the like. Labels may be adhered to a product or to a container in which the product is packaged. In the manufacturing industry, where such labels are read automatically, it is important for the information to be printed such that it is clear and positioned accurately so that an automated reader can consistently and correctly read the information. Some known labelling machines apply pre-printed labels to an article. Other known labelling machines print information onto labels immediately before printed labels are applied to an article. Such labelling machines may be referred to as print and apply labelling machines. It is desirable to be able to advance a web of labels to be applied to an article accurately, so as to ensure that print is accurately positioned on the label and / or to ensure that the label is accurately positioned on the article. There remains a need to provide an improved labelling machine. 69775951-1 Summary In a first aspect of the disclosure there is provided a labelling machine. The labelling machine comprises a supply spool support for supporting a supply spool comprising label stock. The label stock comprises a web and a plurality of labels attached to the web. The labelling machine further comprises a take-up spool support configured to take up a portion of the web. The labelling machine further comprises a motor. The motor is configured to advance the web along a web path from the supply spool support towards the take up spool support. The labelling machine further comprises a labelling peel beak. The labelling peel beak is located along the web path. The labelling peel beak is configured to peel the labels from the web as the web passes the labelling peel beak. The labelling machine further comprises a movable member. The movable member isconfigured to contact a portion of the web and define a portion of the web path betweenthe labelling peel beak and the take-up spool support. Movement of the moveable member changes a length of the web path. A position of the movable member is controllable via an actuator. The labelling machine further comprises a controller configured to control the actuator to adjust the position of the movable member, and control a position of the motor. The motor may drive the take-up spool. The motor may drive the take-up spool directly. The motor may drive the take-up spool indirectly, such as via a belt or gears. The controller may be configured to control the position of the motor to control a speed or acceleration of the motor. The controller may be configured to control the position of the actuator to control a speed or acceleration of the movable member. Since the position of the movable member is controllable via an actuator, controlling the actuator to adjust the position of the movable member and controlling the movable member to change the length of the web path may be used interchangeably. In use, the speed of the web varies. Each time a target item passes the labelling machine, the web speed is caused by the labelling machine to increase to match the target item speed and a label is applied to the target item. The web speed is then decreased to prevent a subsequent label passing the label peeling beak before a subsequent target item passes the labelling machine (although in practice this may occur due to gaps 69775951-1 between target items). This requires acceleration and deceleration of the web. Since movement of the movable member changes the length of the web path, movement of the movable member may contribute towards acceleration and deceleration of theweb. Therefore, the acceleration (or deceleration) of the web is a sum of that caused bythe motor and that caused by movement of the movable member. This allows the labelling machine to achieve higher levels of acceleration than would be possible without the presence of the movable member. Furthermore, the acceleration that is to be provided by the motor in use is reduced as compared to if the movable member were not provided. Reducing the acceleration that is to be provided by the motor in use advantageously improves label placement. This is because acceleration of the motor, and therefore of the take-up spool, results in vibration of the labelling machine, which can impact label placement. Vibration of the labelling machine may include vibration of the machine itself and / or of the label stock. Although movement of the movable member may also result in movement of the labelling machine, this is insignificant as compared to the movement of the labelling machine caused by acceleration of the motor. Furthermore, since the acceleration and deceleration that is required from the motor is reduced, as compared to if the moveable member were not provided, the reliability of the labelling machine is improved. The reduced acceleration and deceleration of the motor reduces the likelihood of damage to components of the labelling machine because the force imparted on them as a result of the acceleration and deceleration of the motor is reduced. Since the movable member defines a portion of the web path between the labelling peel beak and the take-up spool support, the motion characteristics of the web at the labellingpeel beak can be decoupled from the motion characteristics of the motor that is coupledto the take-up spool support. For example, the motor may be accelerating, while the movable member acts to decrease the length of the web path. This allows the speed of the web at the labelling peel beak to be constant. Furthermore, in use, the mass of web supported on the take-up spool support increases, which makes acceleration of the take-up spool support increasingly difficult. By supplementing the acceleration of the motor with the acceleration provided by the 69775951-1 movable member, the maximum required of the motor that drives the take- up spool support is reduced. This further improves label placement and the reliability of the labelling machine. Furthermore, since the required acceleration of the motor is reduced, a less powerful motor is required to achieve a given level of acceleration. This advantageously makes the labelling machine more cost efficient. An alternative means to control the acceleration of the label stock is through use of a nip drive that engages the web of the label stock downstream of the label peeling beak. However, nip drives are undesirable because they contact both sides of the label web, which can result in the build-up of adhesive over time, ultimately resulting in reliability issues. The controller being configured to control the position of movable member and the position of the motor may comprise the controller being configured to control the motor and the movable member to adjust a speed of the web passing the labelling peel beak. The controller being configured to control the motor and the movable member to adjust a speed of the web passing the labelling peel beak may comprise the controller being configured to control the motor and the movable member to accelerate or decelerate the web passing the labelling peel beak to a first target speed or to a second target speed. The first target speed and the second target speed may be predetermined. The first target speed may be based on a signal indicative of a speed of a target item to which a label is to be applied. The second target speed may be zero. The controller being configured to control the motor and movable member to accelerateor decelerate the web passing the labelling peel beak may comprise the controller beingconfigured to accelerate or decelerate the motor, and accelerate the movable member to increase or decrease the length of the web path. 69775951-1 Acceleration, or movement, of the member in a first direction may increase the length of the web path. Acceleration, or movement, of the movable member in a second direction may decrease the length of the web path. The controller may be configured to decelerate the movable member while adjusting the length of the web path. The controller being configured to accelerate or decelerate the motor and accelerate themovable member to increase or decrease the length of the web path may comprise thecontroller being configured to accelerate or decelerate the motor, and accelerate the movable member to increase or decrease the length of the web path such that the speed of the web passing the labelling peel beak oscillates between the first target speed and the second target speed. The controller may be configured to decelerate the movable member while the speed of the web at the label peeling beak oscillates between the first target speed and the second target speed. The controller may be configured to accelerate the motor and accelerate the movable member in a direction that decreases the length of the web path such that the speed of the web passing the labelling peel beak is maintained at the first target speed for a predetermined amount of time. The controller may be configured to decelerate the movable member while the speed of the web passing the labelling peel beak is maintained at the first target speed for the predetermined amount of time. The predetermined amount of time may correspond to a period of time taken to apply a label to the target item. The controller being configured to accelerate the motor and accelerate the movablemember to increase the length of the web path may comprise the controller beingconfigured to determine a movable member acceleration based on data indicative of a speed of a target item and a predetermined acceleration of the motor such that the speed of the web at the labelling peel beak is within 1% of the speed of the target item. In 69775951-1 addition, the controller being configured accelerate the motor and accelerate the movable member to increase the length of the web path may comprise the controller being configured to accelerate the motor at the predetermined acceleration and accelerate the movable member at the determined movable member acceleration. The controller may be configured to decelerate the movable member prior to the speed of the web at the label peeling beak being within 1% of the speed of the target item. The movable member acceleration or deceleration may be determined such that the speed of the web at the labelling peel beak generally matches the speed of the target item. The movable member acceleration or deceleration may be determined such that the speed of the web at the labelling peel beak is within 0.1% of the speed of the target item. The movable member acceleration or deceleration may be determined such that the speed of the web at the labelling peel beak is within 10% of the speed of the target item. The data that is indicative of a speed of the target item may be stored in a memory associated with the controller, or received as a signal. The predetermined acceleration of the motor may be a maximum acceleration of the motor. The predetermined acceleration of the motor may be less than the maximum acceleration of the motor. The controller is configured to accelerate the motor and the movable member simultaneously. The controller may be configured to determine that a label of the plurality of labels has been applied to a target item. The controller may be configured to subsequently control the motor and movable member to adjust a speed of the web passing the labelling peel beak. The controller may control the motor and the movable member such that the speed of the web passing the labelling peel beak is zero. The controller being configured to control the motor and the movable member to adjust a speed of the web passing the labelling peel beak may comprise the controller being 69775951-1configured to decelerate the motor and the movable member to decrease thelength of the web path. The controller being configured to decelerate the motor and accelerate the movablemember to decrease the length of the web path may comprise the controller beingconfigured to decelerate the motor and accelerate the movable member to decrease the length of the web path such that the speed of the web passing the label peeling beak is decelerated to a predetermined speed. The predetermined speed may be zero. The controller may be configured to decelerate the motor while the length of the path web is being decreased. The controller being configured to decelerate the motor and accelerate the movable member to decrease the length of the web path may comprise the controller being configured determine a movable member acceleration based on a current speed of theweb at the label peeling beak, data indicative of a predetermined deceleration of themotor, and a target web speed. The controller may be configured to decelerate the motor at the predetermined deceleration and accelerate the movable member at the determined movable member acceleration such that the target web speed is achieved. The controller may be configured to decelerate the movable member prior to the target web speed being achieved. The target web speed may be zero, or non-zero. The data indicative of a predetermined deceleration of the motor may be stored in a memory associated with the controller. The data indicative of a predetermined deceleration of the motor may be received as a signal. Deceleration of the motor and acceleration of the movable member may occur simultaneously. The movable member may be pivotable to increase or decrease the length of the web path. Where the movable member is pivotable to increase or decrease the length of the web path, the acceleration of the web provided by the movable member can be greater for a given displacement of the movable member. This is as compared to if the movablemember were translatable to increase or decrease the length of the web path (and69775951-1 therefore accelerate or decelerate the . This is because the required displacement of the actuator is reduced for a given change in path length. Furthermore, where the movable member is pivotable rather than translatable to increase or decrease the length of the web path, the labelling machine can be more compact. This is because components that allow pivotable control of the movable member are generally smaller than those that allow translation of the movable member. The movable member may be pivotable between a first position that corresponds to a minimum length of the web path, and a second position that corresponds to a maximum length of the web path. The movable member may be operated in a range of 30 degrees and 150 degrees from the first position. The operating range of the movable member may refer to an operating range during a label application. The movable member may only be operated in the range of 30 degrees and 150 degrees from the first position. The movable member may be operated in the range of 45 degrees and 135 degrees from the first position. The movable member may only be operated in the range of 45 degrees and 135 degrees from the first position. A maximum change in path length per degree of rotation may be achieved at 90 degrees from the first position. Where the movable member is operated in the range of 30 degrees and 150 degrees from the first position, operation of the movable member is advantageously more efficient. This is because the amount of rotational movement to achieve a desired change in path length is reduced. This is as compared to, for example, if the movable member were to operate in a range of zero degrees to 90 degrees from the first position.The movable member may comprise a roller that comprises a first axis and a secondaxis. The movable member may be rotatable about the first axis to support the web. Themovable member may be pivotable about the second axis to change the length of theweb path. The first axis may be parallel to the second axis. 69775951-1 The moveable member may comprise a roller that comprises a first axis and a second axis. The movable member may be rotatable about the first axis to support the web. The movable member may be translatable along the second axis to change the length of the web path. The second axis may be disposed within an external periphery of the roller.The labelling machine may further comprise a cover. The cover may be coupled to adistal end of the movable member and to a distal end of a roller that is disposed adjacent the movable member. Where the labelling machine further comprises a cover that is coupled to distal end of the movable member and to a distal end of a roller that is disposed adjacent the movable member, the stability of the movable member is improved. This is because the movable member is supported at both its ends. Improving the stability of the movable member advantageously improves the reliability of the labelling machine.The actuator may be a motor.The motor may be a position controlled motor.The motor may be a stepper motor. The stepper motor may have an output shaft coupledto the movable member. The stepper motor may be arranged to vary the position of themovable member. The labelling machine may further comprise a sensor configured to generate a signal indicative of an angular position of the output shaft of the stepper motor. The controller may be configured to generate control signals for the stepper motorso as to cause a magnetic field to be generated by windings of the stepper motor. A fieldangle may be defined between an angular position of the output shaft of the steppermotor, and an orientation of the generated magnetic field. The control signals may be configured to cause the field angle to not exceed a predetermined maximum value. The control signals may be configured to cause the field angle to have a predetermined value. The control signals may be configured to cause the magnetic field to have a predetermined magnitude. 69775951-1 By use of an encoder associated with the output shaft of the stepper motor, it is possible to provide accurate positional information regarding the actual rotor position, therebyallowing a motor field angle to be accurately controlled. Control of the field angle in thisway allows a maximum output torque to be generated by the motor for a given current level, while also reducing the risk that a stepper motor will stall. In this way, it is possible to provide a smaller stepper motor (i.e. one having a smaller maximum torque capacity), and a correspondingly smaller power supply for a given torque requirement. That is, rather than having to provide an excess torque capacity, so as to prevent against stall conditions (and the associated loss of motor control), the motor can be controlled in a field controlled manner to generate a maximum torque when required, without any risk that the motor will stall. The signal indicative of the angular position of the motor outputshaft can thus be used to ensure that the control signals supplied to the motor do notcause the magnetic field to rotate to a position beyond the capacity of the motor toprovide torque, thereby maintaining the predetermined (and optimal) field angle, while delivering a desired motion profile. The control signals for the stepper motor may comprise control signals supplied to windings of the stepper motor. For example, a stepper motor may generate a maximum torque for a given magnitude of winding current when the field angle has a predetermined value (e.g. 90 electrical degrees). The controller may be configured to generate a target motor position based on a desiredmotion profile. The controller may be configured to control the motor to rotate to the targetmotor position.In a second aspect of the disclosure there is provided a method of operating a labellingmachine. The labelling machine comprises a supply spool support for supporting asupply spool comprising label stock. The label stock comprises a web and a plurality oflabels attached to the web. The labelling machine further comprises a take-up spool support configured to take up a portion of the web. The labelling machine further comprises a motor configured to advance the web along a web path from the supply spool support towards the take up spool support. The labelling machine further 69775951-1 comprises a labelling peel beak located the web path and configured to peel the labels from the web as the web passes the labelling peel beak. The labelling machine further comprises a movable member. The movable member is configured to contact aportion of the web and define a portion of the web path between the labelling peel beakand the take-up spool. Movement of the moveable member changes a length of the web path. A position of the movable member is controllable via an actuator. The method comprises controlling the actuator to adjust the position of the movable member; and controlling the position of the motor. The method may comprise controlling a speed or an acceleration of the motor.The method may further comprise adjusting a speed of the web passing the labellingpeel beak by controlling the motor and the movable member.The method may further comprise accelerating or decelerating the web passing thelabelling peel beak to a first target speed or to a second target speed by controlling the movable member and the motor. The first target speed and the second target speed may be predetermined. The first target speed may be based on a signal indicative of a speed of a target item to which a label is to be applied. The second target speed may be zero. To accelerate or decelerate the web passing the labelling peel beak to the first target speed or to the second target speed, the motor may be accelerated or decelerated and the movable member may be accelerated to increase or decrease the length of the web path. The movable member may be decelerated while adjusting the length of the web path. The motor may be accelerated or decelerated and the movable member may be accelerated to increase or decrease the length of the web path such that the speed of the web passing the labelling peel beak oscillates between the first target speed and the second target speed. 69775951-1 The movable member may be the speed of the web at the label peeling beak oscillates between the first target speed and the second target speed. The motor may be accelerated and the movable member may be accelerated in a direction that decreases the length of the web path such that the speed of the web passing the labelling peel beak is maintained at the first target speed for a predetermined amount of time. The movable member may be decelerated while the speed of the web passing the labelling peel beak is maintained at the first target speed for the predetermined amount of time. The method may further comprise determining a movable member acceleration based on data indicative of a speed of a target item and a predetermined acceleration of the motor such that the speed of the web at the labelling peel beak is within 1% of the speed of the target item. The method may further comprise accelerating the motor at the predetermined acceleration. The method may further comprise accelerating the movable member at the determined movable member acceleration. The movable member may be decelerated prior to the speed of the web at the label peeling beak being within 1% of the speed of the target item. The method may comprise determining a movable member acceleration or deceleration such that the speed of the web at the labelling peel beak generally matches the speed of the target item. The method may comprise determining a movable member acceleration or deceleration such that the speed of the web at the labelling peel beak is within 0.1% of the speed of the target item. The method may comprise determining a movable member acceleration or deceleration such that the speed of the web at the labelling peel beak is within 10% of the speed of the target item. In a third aspect of the disclosure there is provided a labelling machine. The labellingmachine comprises: a supply spool support for supporting a supply spool comprisinglabel stock, the label stock comprising a web and a plurality of labels attached to theweb; a take-up spool support configured to take up a portion of the web, the labellingmachine being configured to advance the web along a web path from the supply spool 69775951-1 support towards the take up spool a labelling peel beak located along the web path and configured to peel the labels from the web as the web passes the labelling peel beak; a stepper motor configured to control a position of a component of the labelling machine that causes movement of a portion of the web extending between the supplyspool support and the take up spool support; a sensor configured to generate a signalindicative of an angular position of an output shaft of the stepper motor; and a controller configured to control the control the angular position of the stepper motor. The controller is configured to generate motor control signals for the stepper motor so as to cause a magnetic field to be generated by windings of the stepper motor, a field angle beingdefined between an angular position of the output shaft of the stepper motor and anorientation of the generated magnetic field, the motor control signals being configured to cause the field angle to not exceed a predetermined maximum value. The stepper motor may be controlled in a “position controlled” manner, such that the motor is caused to rotate according to a position control signal, thereby causing movement of the portion of web in a desire way (e.g. in accordance with a desired motion profile). However, in order to reduce the risk of a stepper motor stalling, the angularposition of the motor shaft is monitored (via the sensor), and the field angle between themagnetic field and the rotor position limited so as not to exceed a maximum value. The stepper motor may thus be considered to be operated in a position controlled manner, with stall prevention. The predetermined maximum value may be determined based on a characteristic of the stepper motor. For example, the predetermined maximum value may correspond to one full step (e.g. 1.8 degrees, for a device having 200 steps / revolution) at a native resolution of the stepper motor. The predetermined maximum value may correspond to an electrical angle of 90 degrees. That is, a stepper motor typically comprises a periodic structure, such that each rotation by four full steps corresponds to an electrically identical configuration, and advancing a field by 360 electrical degrees corresponds to a predetermined number of full steps (e.g. four full steps). 69775951-1 The predetermined maximum value comprise a predetermined maximum magnitude value. That is, the permitted field angle values may be positive or negative, and may have a maximum magnitude value. The controller may be configured to generate a plurality of position control signals at acorresponding plurality of times. Each of the position control signals may define arespective target position for the motor shaft at the corresponding time. The plurality of times may be regularly spaced in time. For example, a motion controller may be configured to generate a new position control signal each 50 μs (e.g. 20 kHz update frequency). Alternatively, the plurality of times may correspond to a regularly spaced angular positions. In such an arrangement, a particular position control signal may be amended(e.g. delayed, or made earlier) if needed to avoid extending the field angle beyond themaximum value.For each of the generated position control signals, the controller may be configured tocompare the target position with data indicative of an angular position of an output shaft of the stepper motor, and to generate the motor control signals for the stepper motor based upon the output of the comparison. The data indicative of an angular position of an output shaft of the stepper motor may begenerated based on: the signal indicative of an angular position of an output shaft of thestepper motor; and data indicative of a rotational speed of the output shaft of the stepper motor. That is, in view of expected system latency (e.g. the time taken for a received encoder signal to be received and processed, to generate data indicative of an angular position of an output shaft of the stepper motor, and / or for control signals to reach to motor to cause a further movement of the motor), it may be advantageous to apply some latency compensation. The latency compensation may depend on the speed of the motor shaft, since while any processing delay may be generally fixed, the distance covered by the rotating motor during such a delay will depend upon the motor speed. The rotational speed used in any such compensation may be selected from, or derived from, a 69775951-1 previously determined motor speed, a motor speed, or an extrapolated motor speed, for example.The controller may be configured to: determine whether a difference between anorientation of a magnetic field of the motor corresponding to the target position and the data indicative of an angular position of an output shaft of the stepper motor exceeds the predetermined maximum value; and, if the difference exceeds the predetermined maximum value, generate a modified position control signal. The modified position control signal may correspond to a modified target position. A difference between an orientation of a magnetic field of the motor corresponding to the modified target position and the data indicative of an angular position of an output shaft of the stepper motor may not exceed the predetermined maximum value. The modified target position may be determined such that the difference between the orientation of a magnetic field of the motor corresponding to the modified target position and the data indicative of an angular position of an output shaft of the stepper motor equals the predetermined maximum value. The controller may be configured to generate motor control signals for the stepper motor corresponding to the target position or the modified target position. If the difference is less than or equal to the predetermined maximum value, the controller may be configured to generate motor control signals for the stepper motor corresponding to the target position. If the difference is greater than the predetermined maximum value, the controller may be configured to generate motor control signals for the stepper motor corresponding to the modified target position. The modified position control signal may correspond to a delayed target position. An expected difference between an orientation of a magnetic field of the motor corresponding to the delayed target position and the data indicative of an angular position of an output shaft of the stepper motor may be controlled so as not to exceed the predetermined maximum value. 69775951-1 That is, rather than modifying the target position it is possible to modify the timing of the delivery of the control signal, so as to allow the motor shaft to catch-up. In such an arrangement, the position control signal may comprise a series of target position that are spaced regularly in terms of angular offset (e.g. single steps, or micro-steps). Similarly, the timing may be modified to deliver a position control signal at an earlier time. The modified position control signal may be referred to as a time shifted target position. An expected difference between an orientation of a magnetic field of the motor corresponding to the time shifted target position and the data indicative of an angular position of an output shaft of the stepper motor may be controlled so as not to exceed the predetermined maximum value. The controller may be configured to monitor data indicative of the generation of the modified position control signal. While short term discrepancies between the actual motor movement and the desired motion profile may be accommodated, monitoring for the accumulation of errors may permit a controller to alter system behaviour, or to raise a warning to a user. The controller may be configured to generate a fault condition if the data indicative of the modified position control signal exceeds a predetermined threshold. The fault condition may result in a visible or audible warning being raised to a machine operator, and / or may result in labelling operations being paused. The controller may be configured to generate a first fault condition if the data indicative of the modified position control signal satisfies a first condition, and generate a second fault condition if the data indicative of the modified position control signal satisfies a second condition. The component of the labelling machine that causes movement of the portion of the web extending between the supply spool support and the take up spool support may comprise the take up spool support. 69775951-1 That is, the stepper motor may be to cause spool support to rotate to cause the web to advance along the web path. The stepper motor may be controlled in a “position controlled” manner. The position control signal may be used to advance the web along the web path in a controlled manner to achieve a desired label stock motion profile. The stepper motor output shaft may be coupled directly or indirectly to the take up spool support. The stepper motor output shaft may be coupled to the take up spool support via fixed gear ratio. The labelling machine may be configured to advance the web along a web path from the supply spool support towards the take up spool support by causing the stepper motor to rotate, thereby causing the take up spool support to rotate. By driving the take-up spool support with the stepper motor to cause a controlled label advance, it is possible to provide accurate label motion and placement. Driving the take- up spool support, rather than relying on a nip drive arrangement for label placement minimises the risk that contamination (e.g. glue / debris) becoming attached to the nip drive will result in disruption. It will be appreciated, however, that where a stepper motor is used in this way, a stall event could be catastrophic to label placement accuracy, since a loss of motor synchronisation could result in loss of web control. Each of the plurality of position control signals may correspond to an angular position of the take up spool support. The controller may be configured to cause the web to advance by providing motor control signals corresponding to the plurality of position control signals to the motor.The labelling machine may further comprise a motion controller configured to generatethe plurality of position control signals based upon a label motion profile. The label motion profile may be determined based on a motion profile of product on a production line upon which a label is to be applied by the labelling machine. 69775951-1 The controller may be configured to each of the plurality of position control signals to a corresponding an angular position of the take up spool support. The conversion may be based upon the diameter of the take up spool. The labelling machine may further comprises a movable member. The movable member may be configured to contact a portion of the web and define a portion of the web path between the labelling peel beak and the take-up spool support. Movement of the moveable member may change a length of the web path. The position of the movable member may be controlled by the stepper motor. The movable member may comprise the component of the labelling machine that causes movement of the portion of the web extending between the supply spool support and the take up spool support comprises the take up spool support. The movable member may comprise a roller that comprises a first axis and a second axis, the movable member being rotatable about the first axis to support the web and being pivotable about the second axis to change the length of the web path. The second axis may be disposed within an external periphery of the roller.The labelling machine may comprise a further motor configured to advance the webalong a web path from the supply spool support towards the take up spool support. Thefurther motor may comprise a stepper motor.The controller may be configured to control the position of movable member and theposition of the motor to adjust a speed of the web passing the labelling peel beak. The controller may be configured to control the further motor and the movable member to accelerate or decelerate the web passing the labelling peel beak to a first target speed or to a second target speed. The labelling machine may comprise: a first stepper motor configured to cause the take up spool support to rotate to advance the web along a web path from the supply spool support towards the take up spool support, and a second stepper motor configured to control the position of the movable member. The controller may be configured to 69775951-1 generate a target motor position for of the first stepper motor and the second stepper motor based on a desired motion profile, and to control the first stepper motor and the second stepper motor to rotate to the respective target motor position. Each of the movable member and the take-up spool support may be controlled by a stepper motor operated in a position controlled mode with stall-prevention. The controller may be configured to generate a plurality of target motor positions for each of the first stepper motor and the second stepper motor based on the desired motion profile. The component of the labelling machine that causes movement of the portion of the web extending between the supply spool support and the take up spool support may comprisea drive roller. The motor may be configured to cause the drive roller to rotate to advancethe web along the web path from the supply spool support towards the take up spool support. The stepper motor may be controlled in a “position controlled” manner. The position control signal may be used to advance the web along the web path in a controlled manner to achieve a desired label stock motion profile. The stepper motor output shaft may be coupled directly or indirectly to the drive roller. The stepper motor output shaft may be coupled to the nip drive roller via fixed gear ratio. The labelling machine may further comprise a nip roller configured to bear against the drive roller. In use, the web may be pressed between the drive roller and the nip roller. There is also provided a method of operating a labelling machine according to the first aspect. The method may include any of the optional features described above in the context of the labelling machine.According to a fourth aspect of the disclosure, there is provided a method of operating alabelling machine. The method comprises: advancing a web along a web path, the websupporting a plurality of labels; peeling labels from the web as the web passes a labellingpeel beak of the labelling machine; controlling, by a stepper motor, a position of a69775951-1component of the labelling machine to movement of a portion of the web alongthe web path. The controlling comprises: generating motor control signals for the steppermotor so as to cause a magnetic field to be generated by windings of the stepper motor, a field angle being defined between an angular position of the output shaft of the stepper motor and an orientation of the generated magnetic field, the motor control signals being configured to cause the field angle to not exceed a predetermined maximum value. The labelling machine and associated method may comprise one or more of the features described above in connection with the first aspect.The method may further comprise generating a plurality of position control signals at acorresponding plurality of times, each of the position control signals defining a respective target position for the motor shaft at the corresponding time. The method may further comprise, for each of the generated position control signals,comparing the target position with data indicative of an angular position of an output shaftof the stepper motor, and generating the motor control signals for the stepper motorbased upon the output of the comparison. The method may further comprise receiving a signal indicative of an angular position ofan output shaft of the stepper motor from a sensor. Generating the data indicative of anangular position of an output shaft of the stepper motor may be based on the signalindicative of an angular position of an output shaft of the stepper motor. Generating the data indicative of an angular position of an output shaft of the steppermotor may be further based on data indicative of a rotational speed of the output shaftof the stepper motor.The data indicative of a rotational speed of the output shaft of the stepper motor may begenerated based on a plurality of signals received from the sensor.The component of the labelling machine configured to cause movement of a portion ofthe web along the web path may comprise a take-up spool support. The labelling machine may advance the web along a web path from the supply spool support towards 69775951-1 the take up spool support by causing motor to rotate, thereby causing the take up spool support to rotate.The component of the labelling machine configured to cause movement of a portion ofthe web along the web path may comprise a moveable member. Movement of themoveable member may change a length of the web path.The component of the labelling machine configured to cause movement of a portion ofthe web along the web path may comprise a drive roller. Rotation of the drive roller mayadvance the web along the web path from the supply spool support towards the take up spool support. Features disclosed in relation to one aspect of the invention may be combined with other aspects of the invention. Brief Description of the Drawings Embodiments of the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 shows a first conventional labelling machine; Figure 2 shows a second conventional labelling machine; Figure 3 shows a labelling machine according to an embodiment of the present disclosure; Figure 4 shows a portion of the labelling machine of Figure 3; Figure 5 shows a cover of the labelling machine of Figure 3; Figures 6a and 6b show a portion of the labelling machine of Figure 3 with a movable member of the labelling machine in a first configuration and a second configuration respectively; Figure 7 shows a portion of the labelling machine of Figure 3 with the movable member in the first and second configurations; Figures 8 to 11 show an alternative embodiments of movable members that may be used with the labelling machine of Figure 3; Figure 12 shows a motor controller that may be used with the labelling machine of Figure 3; Figures 13a to 15c show graphs that include a motion plots for the labelling machine during labelling operations; 69775951-1 Figure 16 shows a graph that a plot of the relationship between the angular position of the movable member of the previously described embodiments and the resulting change in a length of a web path of the labelling machine per degree of rotation; Figure 17 shows a controller that may be used with a labelling machine describedin the present disclosure; Figure 18 shows a motor driver that may be used with a labelling machinedescribed in the present disclosure; Figure 19 shows a torque characteristic of a motor that may be used with alabelling machine described in the present disclosure; Figure 20 shows a method performed by a controller of Figure 17;Figure 21 shows a segment of a motion profile for moving a motor according toan embodiment; andFigure 22 shows an alternative machine according to an embodiment. Detailed Description Figures 1 and 2 show schematic side views of portions of two different types of labelling machine, such as that described in WO2014 / 072728 A1, which is hereby incorporated by reference. Figure 1 shows a labelling machine with no integrated printer and Figure 2 shows a labelling machine with an integrated printer. The labelling machines shown in Figures 1 and 2 both include a supply spool support 10 and a take up spool support 12. The supply spool support 10 and take up spool support 12 are both mounted for rotation about respective axes A and B. In the labelling machines shown in Figures 1 and 2 the axes A and B are substantially parallel to one another; however, in some examples this may not be the case. The take up spool is connected to a motor 14 such that the motor 14 can be powered in order to rotate the take up spool support 12 about the axis B. The motor 14 may be connected to the take- up spool support 12 directly, or may be connected via a belt or gears. In the labelling machines shown in Figures 1 and 2, the motor 14 is connected to the take up spool support 12 via a belt (not shown). However, it will be appreciated that any appropriate linkage may be used to connect the motor 14 to the take up spool support 12. For example, while in the described example the belt will provide a fixed transmission ratio between rotation of the motor shaft and rotation of the take up spool support, in other examples a linkage providing a variable 69775951-1 transmission ratio (such as a gearbox) be provided. Indeed, the take up spool support 12 may be directly driven by the motor 14. By directly driven it is meant that the spool support may be mounted co-axially with the shaft of the motor 14, that is the shaft of the motor 14 may extend along the axis B. In the case where the take up spool support 12 is directly driven by the motor 14, the take up spool support may be mounted to a motor spindle of the motor 14. This arrangement is quite different from other arrangements which may use capstan rollers to contact the outside circumference of a spool or a spool support in order to rotate the spool and / or spool support, or nip rollers to advance web between the spool supports. In the labelling machine shown in Figures 1 and 2 the motor 14 is a stepper motor. The stepper motor is controlled via a serial bus that allows the coil currents of the motor tobe set directly. The stepper motor may be a hybrid stepper motor. An example of asuitable belt which connects the motor 14 to the take up spool support 12 is a steelreinforced polyurethane toothed timing belt. The gearing ratio for the belt drive may be4:1 whereby the motor revolves four times for every revolution of the take up spool support. It will be appreciated that in other examples any appropriate gearing ratio for the belt drive may be used. In this case the stepper motor is capable of being controlled such that it can execute substantially equal angular movements per complete rotation of the stepper motor. These substantially equal angular movements may be referred to as micro-steps. Eachmicro-step is equivalent to a rotation of about 0.007º or about 0.000123 radians. In thiscase, the stepper motor has 200 steps per revolution, but the stepper motor is controlled to produce up to 256 micro-steps per step, such that the number of micro-steps per revolution is up to 51200. Because the belt drive gearing ratio is 4 to 1, the number of micro steps of the motor per revolution of the take up spool support is up to 204800. Stepper motors are generally driven by a stepper motor driver. In the case of the motor and control arrangement described above, if the stepper motor driver is commanded to advance one step, the stepper motor driver will provide a signal to the stepper motor which causes the stepper motor to rotate by one micro-step (i.e. about 0.007°). It will be appreciated that the stepper motor may undertake any appropriate number of steps per complete rotation of the stepper motor, and the stepper motor may be controlled to produce any appropriate number of micro-steps per step of the stepper motor. Furthermore, the belt drive gearing ratio may be chosen such that the number of micro 69775951-1 steps of the motor per revolution of the up spool support is any appropriate desired number. The gearing ratio may be fixed. While the term ‘step’ is sometimes used to denote a physical property of a stepper motor, in the present description, the term ‘step’ is used to denote any desired angular movement of the stepper motor, for example a micro-step. Stepper motors are an example of a class of motors referred to as position-controlled motors. A position-controlled motor is a motor controlled by a demanded output rotary position. That is, the output position may be varied on demand, or the output rotational velocity may be varied by control of the speed at which the demanded output rotary position changes. A stepper motor is an open loop position-controlled motor. That is, a stepper motor is generally supplied with an input signal relating to a demanded rotation position or rotational velocity and the stepper motor is driven to achieve the demanded position or velocity. While stepper motors are often considered to be advantageous since they allow an accurate shaft position to be adopted, if a load experienced by the stepper motor exceeds the maximum torque capacity of the motor, the motor may stall, resulting in a loss in positional control. Such a loss of control, during a label feed operation could result in a misplaced label, or even ripped label web. Some position-controlled motors are provided with an encoder providing a feedback signal indicative of the actual position or velocity of the motor. The feedback signal may be used to generate an error signal by comparison with the demanded output rotary position (or velocity), the error signal being used to drive the motor to minimise the error. A stepper motor provided with an encoder in this manner may form part of a closed loop position-controlled motor. It will be understood that this form of closed loop position control may result in instability. Without wishing to be bound by theory, it is believed that lag within the feedback loop, in combination with input stimulus at certain frequencies (e.g. due to mechanical vibrations,jitter, quantization errors in both inputs and outputs, etc.), can result in certain errorsignals being amplified by a conventional feedback loop, and leading to system instability. 69775951-1 It has been realised, however, that the of an encoder in combination with a stepper motor, allows a form of stall-prevention to be implemented, without full closed loop position control, as described in more detail below. An alternative form of closed loop position-controlled motor comprises a DC motor provided with an encoder. The output from the encoder provides a feedback signal from which an error signal can be generated when the feedback signal is compared to a demanded output rotary position (or velocity), the error signal being used to drive the motor to minimise the error. A DC motor which is not provided with an encoder is not a position-controlled motor. It will be appreciated that in a labelling machine other than those shown in Figures 1 and 2, the motor may take any convenient form. For example, the motor may be any appropriate open or closed loop position-controlled motor. When the labelling machines shown in Figures 1 and 2 are in use, a supply spool of label stock may be mounted to the supply spool support 10 such that the supply spool support 10 supports the supply spool. The label machine shown in Figure 1 does not have a supply spool mounted to the supply spool support 10. However, the labelling machine shown in Figure 2 does have a supply spool 16 mounted to the supply spool support 10. The supply spool 16 is mounted to the supply spool support 10 such that the supply spool 16 co-rotates with the supply spool support 10. The supply spool comprise label stock 18, where the label stock 18 comprises a web and a plurality of labels attached to the web. As can be seen best in Figure 2, in use, web of the label stock 18 extends between the supply spool support 10 (and in particular the supply spool 16 mounted to the supply spool support 10) and the take up spool support 12. A web path 20 is defined between the supply spool support 10 and take up spool support 12 by various components and, in use, the web of the label stock is transported along the web path 20. In the labelling machines shown in Figures 1 and 2, first, second and third rollers (22, 24 and 26) define the web path 20 between the supply spool support 10 and take up spool support 12. It will be appreciated that components other than rollers may be used to define the web path 20. Suitable components may be those which impart only a small friction force to the web of the label stock when the web stock contacts it. Furthermore, the web may follow a different path to that shown in Figures 1 and 2. 69775951-1 The web path 20 is also defined by a arm 28 and a labelling peel beak 30. The dancing arm 28 includes a dancing arm roller 32 mounted at one end of the dancing arm 28. In use, the web of the label stock 18 extends along the web path 20 from the supply spool support 10 (and in particular from the supply spool 16) around the first roller 22, around the dancing arm roller 32, around the second roller 24, around the labelling peel beak 30, around the third roller 26 and is wound onto the take up spool support 12 to form a take up spool 34. It will be appreciated that any appropriate number of rollers (or any other appropriate components) may be used to define a desired shape / length of webpath 20. The labelling peel beak 30 may comprise a roller (not shown in Figure 2). Theroller at the peel beak may be provided with an encoder. This allows a position of the label stock 18 to be determined in use. This also allows an amount of web held on the take up spool support 12 to be determined in use. The dancing arm 28 is a movable member which is rotatable about axis A. That is to say, in the labelling machines shown in Figures 1 and 2, the axis of rotation of the dancing arm 38 is coaxial with the axis of rotation of the supply spool support 10 (and the supply spool 16). In other examples this need not be the case. For example, the dancing arm28 may rotate about an axis which is spaced from the axis A of rotation of the supplyspool support 10 (and supply spool 16 if attached). It will also be appreciated that in the labelling machine shown in Figures 1 and 2, the dancing arm 28 is a movable member which defines the web path 20 and movement of the dancing arm 28 changes the length of the web path between the supply spool support 10 and take up spool support 12. It will be appreciated that any other appropriate movable member may be used, providing that movement of the movable member changes the length of the web path between the supply spool support and take up spool support. The labelling machine shown in Figure 2 includes a printer 36 (however, as previously discussed, other examples need not include a printer, such as the example shown in Figure 1). The printer in this case is a thermal transfer printer. However, it will be appreciated that the printer may include any appropriate type of printer, for example, an inkjet printer, a thermal printer or a laser marking system. The printer 36 includes a ribbon supply spool support 38, a ribbon take up spool support 40, a print head 42 and a ribbon guide member 44. In use, a spool of printer ribbon is mounted to the ribbon 69775951-1 supply spool support 38, such that said of printer ribbon constitutes a supply spool 46 of printer ribbon which is supported by the ribbon supply spool support 38. In use, print ribbon from the supply spool 46 passes along a print ribbon path past the print head 42 and is wound on to the ribbon take up spool support 40 so as to form a take up spool 48. In order for print ribbon to be transported from the ribbon supply spool support 38 to the ribbon take up spool support 40, at least the ribbon take up spool support 40 is connected to a motor such that the motor can rotate the ribbon take up spool support 40. Because the printer 36 shown in Figure 2 is a thermal transfer printer, the print ribbon is thermally sensitive such that, as the print ribbon passes the print head 42, at least a portion of the print head 42 can be selectively energised to heat a desired portion of the print ribbon and transfer ink from that portion of the print ribbon to an adjacent substrate. In this case the adjacent substrate is a label that forms part of the label stock 18. During operation of the printer 36, the guide block 44 comprises guide rollers which help to guide the print ribbon as it is transported from the ribbon supply spool support 38 to the ribbon take up spool support 40. The labelling machine may comprise one or more encoders which are capable of outputting a sensor signal which is indicative of an amount of movement of the label web along the label web path. For example, an encoder which measures the rotation of aroller which contacts the label web may be used. Alternatively, a periodic property of thelabel stock may be used to determine an amount of movement of the label web along the label web path. In such examples, the encoder may measure a property of the label stock which is periodic in order to provide a sensor signal which is indicative of an amount of movement of a label web along the label web path. For example, the encoder may use a gap sensor. As the label web advances along the label web path, the gap sensor will measure a periodic property of the label web (i.e. periodic electromagnetic transmission coefficient of the label web). If a pitch length of the labels (i.e. the distancebetween equivalent portions of adjacent labels) is known by a controller of the labellingmachine, then the controller can use this information to calculate an amount of movement of the label web along the label web path based upon the periodic encoder signal. The label stock which is used by either of the labelling machines shown in Figures 1 and 2 comprises a web and a plurality of labels attached to the web. The labels attached to 69775951-1 the web are separable from the web. peel beak 30 is configured such that, during operation of either of the labelling machines shown in Figures 1 and 2, as the label stock 18 is transported along the web path 20 past the labelling peel beak 30, the labelling peel beak 30 separates a passing label from the web. The separated label may then be attached to a desired article. An example of such a desired article is an item passing on a conveyor (not shown) of a production line. However, it will be appreciated that the desired article may be any appropriate article. In the case of the labelling machine shown in Figure 2, it will be appreciated that, prior to the label being attached to a desired article, the printer 36 may print a desired image on the label. The printing may occur prior to the labelling peel beak 30 separating the label from the web of the label stock, or the printing of the image may occur after the labelling peel beak 30 separates the label from the web of the label stock. During operation of the labelling machines shown in Figures 1 and 2 the motor 14 is energised to rotate the take up spool support 12 about its axis B. As this is done, the take up spool support 12 winds label stock 18 onto the take up spool support 12 to form a take up spool 34. The take up spool 34 will include the web of the label stock. Any labels separated from the web of the label stock as they pass the labelling peel beak 30 will not form part of the take up spool 34. The labelling peel beak 30 may be configured to selectively separate labels from the web. In this case, any labels which are not separated from the web of the label stock by the labelling peel beak 30 will be wound onto the take up spool support 12 and therefore form part of the take up spool 34.i The take up spool support 12 may be referred to as a component of the labelling machine that causes movement of a portion of the web extending between the supply spool support 10 and the take up spool support 12. The winding of the label stock 18 (and in particular the web of the label stock) onto the take up spool support 12 will cause the label stock 18 to move along the web path 20 in the direction indicated by arrows C (Figure 2). The winding of the web of the label stock onto the take up spool support 12 causes label stock to be paid out from the supply spool 16 which is supported by the supply spool support 10. This arrangement, whereby the take up spool support 12 is driven so as to transport the label stock in the direction C of label stock transport, and where the supply spool support 10 is not driven may be referred to as a pull-drag system. This is because, in use, the supply spool support 10 provides some resistance (or drag) to the movement of label 69775951-1 web so as to provide tension in the In this case friction within the system provides the drag. For example, the friction may include the friction between the supply spool support and the means which supports the supply spool support for rotation. Drag may also be provided by the inertia of the supply spool. In other examples the drag in a pull-drag system may be actively controlled. For example, a DC motor may be attached to the to the supply spool support and may be energised in a direction which is opposite to the direction in which the supply spool support rotates due to label stock being wound off the supply spool support and on to the take up spool support. In this case, the amount of drag that the DC motor provides to the system can be controlled by controlling the current supplied to the motor and therefore the torque applied by the motor. In other examples, the supply spool support 10 may be driven so that, in use, it rotates the supported supply spool 16. The supply spool support 10 may be driven for rotation in a direction which opposes movement of the label stock in the direction C of label stock transport (which is effected by the rotation of the take up spool support 12). This kind of arrangement is also referred to as a pull-drag system. In other examples the supply spool support 10 may be driven such that it is rotated by a motor in a direction which is complementary to movement of the label stock in the direction C of label stock transport (which is effected by rotation of the take up spool support 12). This type of arrangement may be referred to as a push-pull system. It will be appreciated that in examples of the labelling machine which include a driven supply spool support 10, the supply spool support 10 may be driven by any appropriate motor. Examples of such motors include a DC motor or a position-controlled motor such as, for example, a stepper motor. Figure 3 shows a labelling machine 300. The labelling machine 300 is generally similarto the labelling machine shown in Figure 1 in that it does not comprise a printer. However,a printer may be provided. The labelling machine 300 comprises a gap sensor 36, which detects a gap between adjacent labels of the label stock 18.The labelling machine 300 differs from the labelling machine shown in Figures 1 and 2in that the labelling machine 300 comprises a movable member 50 and a fourth roller 52.In the embodiment of Figure 3, the motor that controls the position of the take up spool support 12 is disposed within a housing 58 of the labelling machine 300. 69775951-1 The movable member 50 is configured contact a portion of the web and defines a portion of the web path 20 between the peel beak 30 and the take up spool support 12. In particular, the movable member 50 defines a portion of the web path 20 between the third roller 26 and the take up spool support 12. Therefore, in use, the movable member 50 contacts a portion of the label stock 18. The fourth roller 52 forms a portion of the web path 20 between the movable member 50 and the take up spool support 12. As will be discussed in more detail below, the movable member 50 is pivotable to increase or decrease the length of the web path 20. In other embodiments, discussed in more detail below, the movable member may be linearly translatable to increase or decrease the length of the web path 20. Figure 4 shows a portion of the labelling machine 300 and includes a cross-sectionalview of the movable member 50 and of the fourth roller 52. The movable member 50comprises a shaft 54 and a roller sleeve 56. In use, the roller sleeve 56 rotates to supportthe label stock 18. Therefore, the movable member 50 functions as a roller to facilitatemovement of the label stock (not shown in Figure 4) from the peel beak (not shown in Figure 4) to the take up spool support (not shown in Figure 4). The shaft 54 comprises a first shaft portion 60 and a second shaft portion 62. The first shaft portion 60 is disposed within the housing 58. The second shaft portion is disposed within the roller sleeve 56. The first shaft portion 60 is integrally formed with the second shaft portion 62. However, this need not be the case and the second shaft portion 62 and the first shaft portion 60 can be separately formed from one another andsubsequently connected via any suitable method such as, for example, welding or anadhesive. The first shaft portion 60 comprises a first end 68 of the shaft 54. The second shaft portion 62 comprises a second end 70 of the shaft 54. A motor 55 is coupled tothe first end 68 of the shaft 54. The motor 55 may be said to be a component part of themovable member 50. The motor 55 is operable to change the position of the movable member 50, in particular the position of the shaft 54. Therefore, controlling the motor 55 to change the position of the shaft 54 may be referred to as controlling the movable member 50. It will be appreciated that any other suitable type of actuator may be used in place of the motor 55. A motor controller (not shown in Figure 4) is configured to control the motor 55 to change the position of the shaft 54. 69775951-1 Changing the position of the movable 50 changes a length of the web path. The movable member 50 is movable between a first position, which corresponds to a minimum length of the web path, and a second position, which corresponds to a maximum length of the web path. Movement of the movable member 50 towards the first position may be referred to as the movable member 50 moving in a first direction. Movement of the movable member 50 towards the second position may be referred to as the movable member 50 moving in a second direction. In use, the movable member 50 may be positioned at any point between the first position and the second position to achieve a desired change in the length of the web path. In addition, during a labelling operation, the movable member 50 may start from the first position, the second position, or at any point between the first position and the second position. In the present embodiment, the movable member 50 is rotatable between the first position and the second position. A plot showing the relationship between the angular position of the movable member and the resulting change in the length of the web path per degree of rotation of the movable member is shown in Figure 16. A minimum angle of rotation corresponds to the first position of the movable member and a maximum angle of rotation corresponds to the second position of the movable member. As can be seen,the relationship between the angular position of the movable member and the resultingchange in the length of the web path per degree of rotation of the movable member isnon-linear. A maximum change in path length per degree of rotation is achieved at anangular mid-point between the first position and the second position (i.e., 90 degreesfrom the first position). During use, the movable member 50 preferably operates in arange of 30 degrees and 150 degrees from the first position. This may be the only rangein which the movable member 50 operates. This advantageously allows operation of the movable member 50 to be more efficient. This is because the amount of rotational movement to achieve a desired change in path length is reduced. This is as compared to, for example, if the movable member were to operate in a range of zero degrees to 90 degrees from the first position. Furthermore, operating the movable member in this range allows the motor that controls the position of the movable member to be operated more efficiently. Since the amount of rotation to achieve a desired change in path length is reduced, the motor can move the movable member at a slower speed. This allows the motor to generate more torque. In some embodiments, the movable member 50 may operate in a range of 45 degrees and 135 degrees from the first position. Where this is the case, the efficiency of operation of the movable member 50 is further improved. A 69775951-1 home position of the movable member be at a position that is 30 degrees fromthe first position. In some embodiments, the home position of the movable member 50may be at a position that is 45 degrees from the first position.The relationship of the position of the movable member 50, in particular the angularposition of the movable member 50, and the length of the web path is stored in the motor controller. Therefore, the motor controller is able to determine a position of the motor (and therefore movable member 50) that is required for a desired web path length. It will be appreciated that the relationship between the length of the web path and the position of the movable member 50 may be derived using the geometry of the labelling machine. In use, the motor controller generates one or more control signals that control a motion profile of the movable member 50. The motion profile of the movable member 50influences, in combination with a motion profile of the motor 14 that controls the positionof the take-up spool support (not shown in Figure 4), the motion profile of the web.Operation of the motor 55 will be discussed in more detail below. The first shaft portion60 defines a central axis 64. When extended beyond the first shaft portion 60, the central axis 64 of the first shaft portion 60 extends through the second shaft portion 62. That is to say, when extended beyond the first shaft portion 60, the central axis 64 of the firstshaft portion 60 is disposed within a periphery of the second shaft portion 62.The second shaft portion 62 comprises a central axis 66. The central axis 66 of the second shaft portion 62 is non-coaxial with the central axis 64 of the first shaft portion 60. In other words, the central axis 66 of the second shaft portion 62 is offset from the central axis 64 of the first shaft portion 60. Since the central axis 66 of the second shaft portion 62 is non-coaxial with the central axis 64 of the first shaft portion 60, rotation of the first shaft portion 60 about its central axis 64 pivots the second shaft portion 62 about the central axis 64 of the first shaft portion 60. The central axis 64 of the first shaft portion 60 and central axis 66 of the second shaft portion 62 are parallel to one another. A central axis (not shown in figure 4) of the roller sleeve 56 is coincident with the central axis 66 of the second shaft portion 62. Therefore, the roller sleeve 56 may be said to rotate about the central axis 66 of the second shaft portion 62.The movable member 50 further comprises an end cap 72. The end cap 72 is securedto the second end 70 of the shaft 54. The end cap 72 is secured to the second end 70 of the shaft 54 by virtue of a screw 71 and two dowels (not depicted). However, it will be 69775951-1 appreciated that any suitable means may used to secure the end cap 72 to the second end 70 of the shaft 54. For example, any other type of fastener may be used, or the end cap 72 may be secured to the second end 70 of the shaft 54 by virtue of welding or an adhesive. The end cap 72 comprises an end cap protrusion 74. The end cap protrusion 74 extends in a direction parallel to the central axis 66 of the second shaft portion 62. A central axis 73 of the end cap protrusion 74 is coaxial with the central axis 64 of the first shaft portion 60. The end cap 72 is not fixedly coupled to the roller sleeve 56.A first bearing 76a is provided between the first shaft portion 60 and the housing 58. Aninner race of the bearing 76a is secured to the first shaft portion 60 and an outer race ofthe bearing 76a is secured to the housing 58. In some embodiments, a further bearingmay be provided between the first shaft portion 60 and the housing. Where the further bearing is provided, as with the first bearing 76a, an inner race of the further bearing is secured to the first shaft portion 60 and an outer race of the further bearing is secured tothe housing 58. Second and third bearings 76b, 76c are provided between the secondshaft portion 62 and the roller sleeve 56. The second and third bearings 76b, 76c aresecured to the second shaft portion 62 and to the roller sleeve 56 via an interference fit.An inner race of each of the bearings 76b, 76c is secured to the second shaft portion 62and an outer race of each of the bearings 76b, 76c is secured to the roller sleeve 56.A cover 78 is coupled to the movable member 50 and to the fourth roller 52. Referring to Figure 5, a cross-sectional view of the cover 78 is shown. The cover 78 comprises a first portion 80 and a second portion 82. The first portion 80 of the cover 78 comprises a first portion recess 84. The second portion 82 of the cover 78 comprises a second portion recess 86. In some embodiments, the recesses 84, 86 may be replaced by through bores. Referring back to Figure 4, the first portion 80 of the cover 78 is secured to the fourth roller 52. The second portion 82 of the cover 78 is secured to the movable member 50. In particular, the second portion 82 of the cover 78 is secured to the end cap 72. In some embodiments, the cover 78 need not be provided, and the movable member 50 may be cantilevered from the housing 58.A fourth bearing 76d is provided between the end cap protrusion 74 and the cover 78.The fourth bearing 76d is disposed in the first portion recess 84 of the cover 78. An innerrace of the bearing 76d is secured to the end cap protrusion 74 and an outer race of thebearing 76d is secured to the cover.69775951-1The first bearing 76a facilitates rotation of the first shaft portion 60 with respect to thehousing 58. The second and third bearings 76b, 76c facilitate rotation of the roller sleeve56 with respect to the second shaft portion 62. The fourth bearing 76d facilitates rotationof the end cap protrusion 74 with respect to the cover 78. Each of the bearings 76a-dare ball bearings. However, it will be appreciated that a different type of bearing couldbe used instead. For example, roller bearings may be used. The fourth roller 52 comprises a shaft 75 and a roller sleeve 77. The shaft 75 is secured to the housing 58 by virtue of a screw 79. The shaft 75 is secured to the cover 78 by virtue of a dowel 81. The dowel 81 is received by the shaft 75 and by the cover 78 by an interference fit. However, it will be appreciated that any other suitable type of fasteners or fastening means may be used to secure the shaft 75 to the housing 54 and to the cover 78. Since the fourth roller 52 is secured to the cover 78, the movable member 50 is better supported in use. This is because the fourth roller 52 supports thesecond end 70 of the shaft 54 of the movable member 50 via the cover 78 in use.Fifth and sixth bearings 76e, 76f are provided between the shaft 75 of the fourth roller52 and the roller sleeve 77. The fifth and sixth bearings 76e, 76f facilitate rotation of theroller sleeve 77 with respect to the shaft 75. The fifth bearing 76e is disposed adjacentthe housing 58 and the sixth bearing 76f is disposed adjacent the cover 78. The innerrace of each bearing 76e, 76f is secured to the shaft 75 via an interference fit. The outerrace of each bearing 76e, 76f is secured to the roller sleeve 77 via an interference fit.Figure 6a shows the movable member 50 in the first position and Figure 6b shows themovable member 50 in the second position. A distance between the movable member50 and the third roller 26 in the first position is less than a distance between the movablemember 50 and the third roller 26 in the second position. Similarly, a distance betweenthe movable member 50 and the fourth roller 52 in the first position is less than a distancebetween the movable member 50 and the fourth roller 52 in the second position. Themovable member 50 is pivotable between the first position and the second position. Thepivoting movement of the movable member changes the path length of the web path 20. Adjusting (i.e., increasing or decreasing) the path length of the web path 20 may adjustan acceleration of the label stock 18 at the labelling peel beak 30, and may adjust aspeed of the label stock 18 passing the labelling peel beak (not shown in Figures 6a and69775951-1 6b), as will be discussed in more detail Figure 7 shows the portion of the labellingmachine 300 with the movable member 50 in both the first position 50a and in the secondposition 50b. Although only two configurations are shown in Figures 6a, 6b, and 7, the position of the movable member 50 is variable in a continuous manner. Therefore, as will be discussed in more detail below, in use, the movable member 50 may be positionedin any suitable position to change the motion of the label stock 18 as appropriate.Figure 8 shows an alternative embodiment of the movable member 150. In thisembodiment, the first shaft portion 160 and the second shaft portion 162 are connected via a linkage 165. The central axis 164 of the first shaft portion 160 does not extend through the second shaft portion 162. Therefore, in this embodiment, the offset, or distance, between the central axis 164 of the first shaft portion 160 and the central axis 166 of the second shaft portion 162 is greater than that of the previous embodiment. As with the previous embodiment, the first shaft portion 160 is coupled to a motor (not shown). Figure 9 shows a further embodiment of the movable member 250. In this embodiment, the movable member 250 is secured to a track 251. The track 251 is a linear track. The position of the movable member 250 along the track 251 is controlled via a drive system253. The drive system 253 comprises a drive roller 255 and a free roller 257. A belt 259extends around the drive roller 255 and the free roller 257. A linkage 261 is secured to the belt 259 and is secured to the movable member 250. The linkage 261 is a rigid linkage. The drive roller 255 is driven by a motor. As depicted, the drive roller 255 is shown as being the right hand roller. However, the functions of the rollers 255, 257 maybe reversed such that the drive roller 255 is the left hand roller. Rotation of the driveroller 255 moves the belt 259, which moves the movable member 250 along the track251. This varies the path length of the web (not shown in Figure 9). Figure 10 shows a further embodiment of a movable member 350. This embodiment also comprises a drive system 353. In this embodiment, the drive system 353 comprises a rack 363 and a pinion 365. The pinion 365 is driven by a motor (not shown in Figure 10). Driving the pinion 365 using the motor translates the rack 363 along the pinion 365 therefore changing the position of the movable member 350. The movable member 350 is secured to the rack 363. 69775951-1 Figure 11 shows a further embodiment movable member 450. The structure of the movable member 450 is similar to that depicted in Figure 4. This embodiment also comprises a drive system 453 that comprises a rack 463 and a pinion 465. In this embodiment, the pinion 465 is secured to the movable member 450 such that a central axis 467 of the pinion 465 is coaxial with the central axis 464 of the first shaft portion 460 of the movable member 450. A linear actuator 470 is coupled to the rack 463. Movementof the linear actuator 470 moves the rack 463 such that the first shaft portion 460 rotatesabout the central axis 464 of the first shaft portion 460, and the second shaft portion 462 pivots about the central axis 464 of the first shaft portion 460.It will be appreciated that while the movable members 50, 150, 250, 350, 450, illustratedwith reference to Figures 4 and 8 to 11 are simply examples of a movable member.Alternative configurations are possible. In each configuration the movable member maybe driven by motor (e.g. motor 55), or other suitable actuator.Figure 12 illustrates a motor controller 88 which is arranged to control the motor 55, soas to control the position of the movable member (not shown in Figure 11) during labellingoperations. Labelling operations will be discussed in more detail below. The motor controller 88 is in communication with, or forms a part of, the controller of the labelling machine. The motor controller 88 comprises a position controller 92.The motor controller 88 generates a control signal which is provided to a stepper motordriver 96. The stepper motor driver 96 in turn generates control signals which areprovided to transistors (not shown) which control the current flowing in the windings ofthe motor 55. An encoder 98 is configured to generate a signal indicative of the angularposition of the output shaft of the motor 55.The position controller 92 generates a control signal 99 configured to set the coil currentsin each of the motor windings so as to cause the field to advance to a desired motorposition (e.g. a micro-step position). The control signal 99 may comprise a plurality ofsignal components (e.g. one for each winding). The control signal 99 may be updated frequently to provide a sequence of movement instructions to the motor. The control signal may be referred to as a plurality of control signals. 69775951-1A motor position signal 100 is received position controller 92 from the encoder 98.When setting the control signal 99, the position controller 92 may ensure that the desired motor position does not exceed a full step position from the actual motor position (asindicated by the motor position signal 100), so as to reduce the risk of motor stall.In this way, the motor controller 88 generates control signals that are passed to thestepper motor driver 96 to control the currents supplied to the windings of the motor 55so as to cause the motor to move to a target motor position. The control signal 99 controlsthe motor to move from an initial position and a final position in a stepwise manner. Thisallows the position of the motor, and therefore of the movable member, to follow a desiredmotion profile during application of a label on to a target item. The desired motion profile may include one or more acceleration phases, and one or more deceleration phases. The desired motion profile may be based on the target motor position. However, rather than being a conventional open loop control system, a field angle can be monitored. Such an arrangement allows a greater degree of control to be provided over the position, speed and acceleration of the motor, with reduced risk of motor stall, and lower powerconsumption than would be exhibited for an open loop position controlled stepper motor.The motor driver 96 generates electrical signals which are provided to the stepper motor55 which in turn cause the windings of the stepper motor to be energised so as to causethe stator field to rotate to a position which will cause the motor’s rotor to move in thedesired way. In this way, the torque generated by the stepper motor 55 can be controlledand optimised. The controller may be generally similar to that described in WO2017 / 216573 or inWO2020 / 200823 when configured as a printhead motor controller. For example, thestepper motor driver 96 may be configured substantially as illustrated in Figure 6 of WO2020 / 200823.As described above, it has been realised that the use of an encoder in combination witha stepper motor, allows a form of stall-prevention to be implemented, without full closedloop position control. The torque generated by a stepper motor depends upon an angleformed between the magnetic field of the rotor and the magnetic field generated by theenergised motor windings. By controlling the field angle (that is, an angular offsetbetween a stator field position and a rotor position) the torque generated by the motor 69775951-1 can be maximised for a particular of current supplied to the motor windings.For example, it may be known that a stepper motor produces maximum torque when afield angle of 90 (electrical) degrees is used. Thus, the use of such a field angle allowsthe stepper motor to generate a maximum torque for a given winding current. Moreover,by generating the control signal such that the field angle does not exceed a predetermined maximum value (e.g. a full step), it is possible to avoid a possible stall condition. By providing accurate positional information, and controlling the stator field based upon this information, there is no risk that a stepper motor will stall if the load is greater thanthe maximum torque capacity. Rather than the motor stalling, the stator field will simplybe controlled so as to rotate to an angle which allows the maximum torque to be provided. Of course, it will be appreciated that the use of a stepper motor also allows the use of conventional open-loop stepper motor control (which may be referred to as steppingmode, or micro-stepping mode) when beneficial. Indeed, the stall-prevention systemdescribed above may allow the motor to be controlled as for a conventionally controlledstepper motor at most times, with the stall-prevention behaviour only being activated inexceptional circumstances (e.g. if a high resistance was encountered). Further, in someembodiments a stepper motor may be operated in a closed loop position controlled manner (as opposed to a closed-loop torque controlled manner, or an open-loop position controlled manner). Such control may be effected by use of the position controller 92. In some label machines, such as the ones depicted in Figures 1 and 2, the speed of the label stock 18 is controlled by the motor that is coupled to the take up spool. In use, the speed of the web of the label stock 18 varies. Each time a target item passes the labelling machine, the web speed increases (following a delay, discussed in more detail below) to match the target item speed and a label is applied to the target item. The web speed then decreases to prevent a subsequent label passing the label peeling beak. This requires repeated acceleration and deceleration of the web. The inventors have foundthat, in some cases, it may be beneficial to supplement the acceleration and decelerationof the web that is provided by the motor of the take-up spool support 12 by providing themovable member 50. 69775951-1As mentioned above, movement of the member 50 adjusts the path length ofthe label stock 18. Where the take-up spool support 12 is stationary, or is rotating in a direction such that the web of the label stock accumulates on the take-up spool support12, an increase in the path length will accelerate the label stock 18 at the peel beak 30(while the path length is being increased). Acceleration of the label stock at the peel beakmay be understood to mean that a speed of the label stock at the peel beak is increased. Where the take-up spool support is rotating in a direction such that the web of the label stock accumulates on the take-up spool support 12, a decrease in the path length willdecelerate the label stock 18 at the peel beak (while the path length is being decreased).Preferably, the rate at which the length of the web is reduced is less than the speed ofthe take-up spool support. This advantageously reduces the likelihood of a reduction in the tension of the web occurring in use. Deceleration of the label stock may be understood to mean that a speed of the label stock at the peel beak is decreased. The phrase “accelerating the movable member” may be understood to refer to an increase inthe speed of the movable member in either direction (i.e., towards the first position of themovable member or towards the second position of the movable member). The phrase “decelerating the movable member” may be understood to refer to a decrease in the speed of the movable member in either direction. It will be appreciated that acceleration of the movable member may cause acceleration or deceleration of the label stock 18 at the peel beak. Whether the acceleration of the movable member causes acceleration or deceleration of the label stock at the peel beak may depend upon whether the movable member is moving towards the second position or towards the first position. As mentioned above, the first position of the movable member corresponds to the minimumweb path length that is achievable and the second position corresponds to the maximumweb path length that is achievable. Acceleration of the movable member in a directionthat is away from the first position accelerates the label stock at the peel beak (wherethe take-up spool support 12 is stationary, or is rotating in a direction such that the web of the label stock accumulates on the take-up spool support 12). Acceleration of the movable member in a direction that is towards the first position decelerates the label stock at the peel beak (where the take-up spool support is rotating in a direction such that the web of the label stock accumulates on the take-up spool support 12).In operation, the motion, in particular the acceleration, of the label stock 18 at thelabelling peel beak 30 is equal to that which is as a result of the motor that is coupled to the take up spool support and that which is as a result of movement of the movable 69775951-1member 50. By supplementing the of the label stock 18 at the labelling peelbeak 30, the acceleration of the label stock 18 that can be achieved is greater thanwithout supplementation provided by the movable member 50. Furthermore, theacceleration of the motor of the take up spool support 12 can be reduced. Thisadvantageously improves the accuracy of label placement and machine reliability, and reduces the required capacity of the motor. Application of a label onto a target item will now be discussed with reference to Figures13a-c. Figure 13a shows a graph 103 that includes a take-up spool displacement plot105, a movable member displacement plot 107, and a label stock displacement plot 109. Figure 13b shows a graph 111 that includes a take-up spool speed plot 113, a movable member speed plot 115, and a label stock speed plot 117. Figure 13c shows a graph 119 that includes a take-up spool acceleration plot 121, a movable member accelerationplot 123, and a label stock acceleration plot 125. The graphs 103, 111, 119 relate toapplication of a label to a single target item. The plots 105, 111, 119 show a motion profile for the take-up spool support. The plots 107, 115, 123 show a motion profile for the movable member. The plots 109, 117, 125 show a motion profile for the label stock (or web). Each motion profile includes an acceleration phase 129, a label application phase 131, and a deceleration phase 133. The label stock plots 109, 117, 125 relate to the motion of the label stock at the labelling peel beak. On a production line, the target item passes a trigger sensor, the trigger sensor then sends a signal to the controller of the labelling machine. To account for the distance between the trigger sensor and the labelling peel beak, an amount of time is allowed to elapse before the controller initiates operation of the motor that is coupled to the take-up spool support and before the controller initiates operation of the motor that controls the position of the movable member. Accelerating or decelerating the motor that is coupled to the take-up spool support may be referred to as accelerating or decelerating the take- up spool support. Accelerating or decelerating the motor that controls the position of the movable member to increase or decrease (i.e., adjust) a path length of the label stock may be referred to as accelerating or decelerating the movable member. The controller then determines an acceleration of the movable member required toachieve a first target speed 127 within a predetermined displacement of the label stock.The predetermined displacement of the label stock may be 3mm. The acceleration of 69775951-1 the movable member may be based on indicative of a speed of the target item and an acceleration of the take-up spool. The acceleration of the take up spool may be predetermined. Acceleration of the movable member may be away from the first positionof the movable member (or towards the second position of the movable member). Oncethe required acceleration is determined, the motor controller generates control signals corresponding to the required acceleration. When executed, the control signals cause the movable member to accelerate at the required acceleration. As discussed above, the control signals move the movable member from an initial position to a final (or target) position in a stepwise manner. The initial position may be 30 degrees from the firstposition of the movable member, or any other position between the first position and thesecond position. The initial position may be 45 degrees from the first position of the movable member. The initial position may be the first position. The final position maybe 150 degrees from the first position of the movable member, or any other positionbetween the first position and the second position. The final position may be 135 degreesfrom the first position of the movable member. The final position may be the secondposition. The acceleration of the movable member may be such that, upon completionof the acceleration phase, the speed of the label stock at the label peeling beak is within1% of the speed of the target item. However, in some embodiments, the acceleration ofthe labelling peel beak may be such that, upon completion of the acceleration phase, the speed of the label stock at the labelling peel beak generally matches, is within 0.1% of, or is within 10% of the speed of the first target item. The controller then initiates operation of the motor that is coupled to the take-up spool support and sends the control signalsfrom the motor controller to the motor that controls the position of the movable membervia the motor stepper motor driver. In particular, the controller accelerates the take-upspool support and accelerates the movable member during the acceleration phase 129until the label stock reaches the first target speed 127. The movable member deceleratesprior to the take-up spool support reaching the first target speed 127.Once the label stock reaches the first target speed 127, the label application phase 131begins and the label is applied to the target item. When the label stock reaches the firsttarget speed 127, the movable member decelerates, whilst continuing to move towardsthe second position, and the take-up spool support continues to accelerate. The movable member decelerates at the same rate at which the take-up spool support accelerates.The net effect of this is that the speed of the web at the label peeling beak is maintainedat the first target speed 127. However, the rate of deceleration of the movable member69775951-1 may be different to the rate of the take-up spool support. As can be seen from the take-up spool speed plot 113 and the movable member speed plot 115, once the speed of the take-up spool support is at the first target speed 127, the speed of themovable member is zero. The first target speed 127 may be a predetermined speed.The label stock may be held at the first target speed 127 for a predetermined period of time. The first target speed 127 may be indicative of a speed of the target item. The firsttarget speed 127 may be 1m / s. However, in some embodiments, the first target speed127 may be greater than or less than 1m / s. As can be seen from the label stock displacement plot 110, the first target speed 127 is achieved over a label stock displacement of 3mm, or 6 milliseconds. This amounts to a label stock acceleration of 167m / s2. In other embodiments, the acceleration of the label stock may be any other suitable value. The acceleration of the label stock can also be seen from the label stock acceleration plot 125. Following application of the label to the target item, thedeceleration phase 133 begins.In the deceleration phase 133, the controller controls the motor that is coupled to the take-up spool support and the motor that controls the movable member to decelerate the label stock to a second target speed 137. In the present embodiment, the second targetspeed 137 is zero. However, in some embodiments, the second target speed 137 maybe non-zero. During the deceleration phase 133, the take-up spool support decelerates. During the deceleration phase 133, the moveable member initially accelerates towards the first position. That is to say, the direction of the acceleration of the movable member in the deceleration phase 133 is opposite to the direction of the acceleration of the movable member in the acceleration phase 129. Since the movable member accelerates towards the first position, the length of the web path is reduced, which decreases the speed of the label stock at the labelling peel beak. The magnitude of the deceleration of the label stock is the sum of that caused by the movable member and that caused by the take-up spool support. This allows the label stock to reach the second target speed sooner than if the movable member were not provided. This can be seen from the graph 111, where the label stock speed plot 117reaches the second target speed 137 sooner than the take-up spool speed plot 113.Following the deceleration phase, the speed of the label stock is zero. 69775951-1 Once the speed of the label stock at the peeling beak is at the second target speed 137, the movable member decelerates, whilst continuing to move towards the first position, at a rate that is equal to the deceleration of the take-up spool support. This allows the speed of the label stock at the labelling peel beak to be held at the second target speed 137. It will be appreciated that the direction of the speed and acceleration of the movable member in the deceleration phase 133 are opposite to that in the acceleration phase 129. The label application shown in Figures 13a-c is just one example of a label application using one example motion profile for each of the movable member, the take-up spool support, and the label stock. Control of the take-up spool support and movable member will change depending upon the parameters for application of labels to target items. Parameters that will influence the control include, but are not limited to, the distancebetween target items, the speed at which the target items are travelling, the length (inthe direction of travel along the production line) of the label, and the rates of acceleration of the take-up spool support and of the movable member. Examples in which these parameters are different to that of the label application shown in Figures 13a-c are discussed below. Application of a label onto a target item will now be discussed with reference to Figures 14a-c. The application of Figures 14a-c differs from that of Figures 13a-c in that the label length is shorter in Figures 14a-c. Figure 14a shows a graph 104 that includes a take- up spool displacement plot 106, a movable member displacement plot 108, and a label stock displacement plot 110. Figure 14b shows a graph 112 that includes a take-up spool speed plot 114, a movable member speed plot 116, and a label stock speed plot 118. Figure 14c shows a graph 120 that includes a take-up spool acceleration plot 122, a movable member acceleration plot 124, and a label stock acceleration plot 126. The graphs 104, 112, 120 relate to application of a label to a single target item. The plots 106, 114, 122 show a motion profile for the take-up spool support. The plots 108, 116, 124 show a motion profile for the movable member. The plots 110, 118, 126 show a motion profile for the label stock (or web). The label stock plots 110, 118, 126 relate to the motion of the label stock at the labelling peel beak. Each motion profile includes an acceleration phase 128, a label application phase 132, a deceleration phase 134, and a reset phase 139. 69775951-1On a production line, the target item a trigger sensor, the trigger sensor thensends a signal to the controller of the labelling machine. To account for the distancebetween the trigger sensor and the labelling peel beak, an amount of time is allowed to elapse before the controller initiates operation of the motor that is coupled to the take-up spool support and before the controller initiates operation of the motor that controls the position of the movable member.The controller then determines an acceleration of the movable member required toachieve a first target speed 130 within a predetermined displacement of the label stock. The acceleration of the movable member may be based on data indicative of a speed of the target item and an acceleration of the take-up spool. The acceleration of the take up spool may be predetermined. Once the required acceleration is determined, the motor controller generates control signals corresponding to the required acceleration. When executed, the control signals cause the motor to accelerate at the required acceleration. As discussed above, the control signals move the motor from an initial position to a final position in a stepwise manner. The acceleration of the movable member may be such that, upon completion of the acceleration phase, the speed of the label stock at the labelpeeling beak is within 1% of the speed of the target item. However, in someembodiments, the acceleration of the labelling peel beak may be such that, upon completion of the acceleration phase, the speed of the label stock at the labelling peel beak generally matches, is within 0.1% of, or is within 10% of the speed of the first targetitem. The controller then initiates operation of the motor that is coupled to the take-upspool support and sends the control signals from the motor controller to the motor thatcontrols the position of the movable member. In particular, the controller accelerates thetake-up spool support and accelerates the movable member during the accelerationphase 128 until the label stock reaches the first target speed 130. The movable memberdecelerates prior to the take-up spool support reaching the first target speed 130.Once the label stock reaches the first target speed 130, the label application phase 132begins and the label is applied to the target item. When the label stock reaches the firsttarget speed 130, the movable member decelerates, whilst continuing to move towards the second position, and the take-up spool support continues to accelerate. The movable member decelerates at the same rate at which the take-up spool support accelerates. The net effect of this is that the speed of the web at the label peeling beak is maintained at the first target speed 130. However, the rate of deceleration of the 69775951-1 movable member may be different to rate of acceleration of the take-up spool support. In some embodiments, when the label stock reaches the first target speed 130, the movable member may be stationary. As can be seen from the take-up spool speed plot 114, the take-up spool support does not reach the first target speed 130 during the label application. The label stock therefore reaches the first target speed 130 by virtueof the motion that is provided by the movable member The first target speed 130 may bea predetermined speed. The label stock may be held at the first target speed 130 for apredetermined period of time. The first target speed 130 may be indicative of a speedof the target item. The first target speed 130 may be 1m / s. However, in some embodiments, the first target speed 130 may be greater than or less than 1m / s. As can be seen from the label stock displacement plot 110, the first target speed 130 is achieved over a label stock displacement of 3mm, or 6 milliseconds. This amounts to a label stock acceleration of 167m / s2. In other embodiments, the acceleration of the label stock may be any other suitable value. The acceleration of the label stock can also be seen from the label stock acceleration plot 126. Following application of the label to the target item, the deceleration phase 134 begins. In the deceleration phase 134, the controller controls the motor that is coupled to the take-up spool support and the motor that controls the movable member to decelerate thelabel stock to a second target speed 135. In the present embodiment, the second targetspeed 135 is zero. However, in some embodiments, the second target speed 135 maybe non-zero. During the deceleration phase 134, the take-up spool support continues toaccelerate. During the deceleration phase, the movable member initially continues to decelerate whilst moving towards the second position before accelerating towards the first position. The rate of deceleration of the movable member whilst moving towards the second position is equal to the rate of acceleration of the movable member towardsthe first position. However, this need not be the case. The rate of deceleration andacceleration of the movable member during the deceleration phase 134 is greater than the rate of acceleration of the take-up spool support, such that the net effect is that the label stock decelerates. Since the movable member accelerates towards the first position, the length of the web path is reduced, which decreases the speed of the label stock at the labelling peel beak. Following the deceleration phase, the speed of the label stock is equal to the second target speed 135. 69775951-1Following the deceleration phase 134, phase 139 begins. The reset phase 139begins once the label stock reaches the second target speed 135. In the depicted label application, upon commencement of the reset phase 139, the take-up spool support is accelerating. However, in some embodiments, the take-up spool support may begin todecelerate upon commencement of the deceleration phase or upon commencement ofthe reset phase 139. Upon commencement of the reset phase 139, the movable member continues to accelerate towards the first position, but at a rate that is less thanthat in the deceleration phase 134. This maintains the label stock speed at the labellingpeel beak at the second target speed. However, in some embodiments, upon commencement of the reset phase 139, the movable member may continue to accelerate at the same rate as in the deceleration phase 134. During the reset phase 139, the motion of the movable member need only account for the acceleration of thetake-up spool support, and not of the web, to maintain the web at the second targetspeed 135. When the take-up spool support begins to decelerate, the movable member also begins to decelerate, while continuing to move towards the first position. The rate of deceleration of the movable member is equal to that of the take-up spool support. Upon completion of the reset phase 139, the speed of the take-up spool support, the movable member, and the label stock is zero. Application of a first label and a second label onto a first target item and a second target item respectively will now be discussed with reference to Figures 15a-c. Figure 15a shows a graph 136 that includes a take-up spool displacement plot 138, a movable member displacement plot 140, and a label stock displacement plot 142. Figure 15b shows a graph 144 that includes a take-up spool speed plot 146, a movable member speed plot 148, and a label stock speed plot 150. Figure 15c shows a graph 152 that includes a take-up spool acceleration plot 154, a movable member acceleration plot 156,and a label stock acceleration plot 158. The plots 138, 146, 154 show a motion profilefor the take-up spool support. The plots 140, 148, 156 show a motion profile for the movable member. The plots 142, 150, 158 show a motion profile for the label stock (or web). The label stock plots 142, 150, 158 relate to the motion of the label stock at the labelling peel beak. The motion profiles each include a first acceleration phase 156, a first label application phase 158, a first deceleration phase 160, a second acceleration phase 162, a second label application phase 164, a second deceleration phase 166, and a reset phase 172. 69775951-1On a production line, the first target item a trigger sensor, the trigger sensor thensends a signal to the controller of the labelling machine. To account for the distance between the trigger sensor and the labelling peel beak, an amount of time is allowed to elapse before the controller initiates operation of the motor that is coupled to the take-up spool support and initiates operation of the motor that controls the position of the movable member.The controller then determines an acceleration of the movable member to achieve a firsttarget speed 168 within a predetermined displacement of the label stock. The acceleration of the movable member may be based on data indicative of a speed of the target item and an acceleration of the take-up spool. The acceleration of the take up spool may be predetermined. Once the required acceleration is determined, the motor controller generates control signals corresponding to the required acceleration. When executed, the control signals cause the motor to accelerate at the required acceleration. As discussed above, the control signals move the motor from an initial position to a final position in a stepwise manner. The acceleration of the movable member may be such that, upon completion of the acceleration phase, the speed of the label stock at the label peeling beak is within 1% of the speed of the first target item. However, in some embodiments, the acceleration of the labelling peel beak may be such that, upon completion of the acceleration phase, the speed of the label stock at the labelling peel beak generally matches, is within 0.1% of, or is within 10% of the speed of the first target item. The controller then initiates operation of the motor that is coupled to the take-up spool support and sends the control signals from the motor controller to the motor that controls the position of the movable member. In particular, the controller accelerates the take-up spool support and accelerates the movable member during the first accelerationphase 158 until the label stock reaches the first target speed 168. The movable memberdecelerates prior to the take-up spool support reaching the first target speed 168.Once the label stock reaches the first target speed 168, the first label application phase158 begins and a first label is applied to the first target item. When the label stock reaches the first target speed 168, the movable member decelerates, whilst continuing to move towards the second position, and the take-up spool support continues to accelerate. The movable member decelerates at the same rate at which the take-up spool support accelerates. The net effect of this is that the speed of the web at the label peeling beak is maintained at the first target speed 168. However, the rate of deceleration of the 69775951-1 movable member may be different to rate of acceleration of the take-up spool support. In some embodiments, when the label stock reaches the first target speed 168, the movable member may be stationary. As can be seen from the take-up spool speed plot 146, the take-up spool support does not reach the first target speed 168 during the label application. The label stock therefore reaches the first target speed 168 by virtue of the motion that is provided by the movable member. The first target speed may be a predetermined speed. The label stock may be held at the first target speed for a predetermined period of time. The first target speed 168 may be indicative of a speed of the target item. The first target speed 168 may be 1m / s. However, in some embodiments, the first target speed 168 may be greater than or less than 1m / s. As can be seen from the label stock displacement plot 142, the first target speed 168 is achieved over a label stock displacement of 3mm, or 6 milliseconds. This amounts to a label stock acceleration of 167m / s2. In other embodiments, the acceleration of the label stock may be any other suitable value. The acceleration of the label stock can also be seen from the label stock acceleration plot 158. The label stock may be held at a constant speed for a predetermined amount of time.Following application of the label to the target item, the first deceleration phase 160begins. During the first deceleration phase 160, the take-up spool support continues to accelerate. During the first deceleration phase, the movable member initially continues to decelerate whilst moving towards the second position before accelerating towards the first position. The rate of deceleration of the movable member whilst moving towards the second position is equal to the rate of acceleration of the movable member towardsthe first position. However, this need not be the case. The rate of deceleration andacceleration of the movable member during the first deceleration phase 160 is greater than the rate of acceleration of the take-up spool support, such that the net effect is thatthe label stock decelerates. Upon completion of the first deceleration phase 160, thespeed of the label stock reaches a second target speed 170. As depicted, the secondtarget speed 170 is zero. However, in other embodiments, the second target speed 170 may be non-zero. The controller then receives a signal from the trigger sensor that indicates that the second target item is approaching the label peeling beak. The controller then determinesan acceleration of the movable member in the same manner as for the first target item,discussed above. The second acceleration phase 162 then commences. The controller69775951-1continues to accelerate the take-up and decelerates the movable member,while the movable member continues to move towards the first position andsubsequently accelerates the movable member towards the second position until thelabel stock at the label peeling beak reaches the first target speed 168. The speed of the take-up spool support is greater in the second acceleration phase 162 than in thefirst acceleration phase 156. Therefore, the speed of the movable member following thesecond acceleration phase 162 is less than in the first acceleration phase 162. However, the speed of the take-up spool support need not be greater in the second acceleration phase 162 than in the first acceleration phase 156. The speed of the take-up spool support in the second acceleration phase 162 may be equal to or greater than the speed of the take-up spool support in the first acceleration phase 156. Once the first target speed 168 is again achieved, the second label application phase164 begins. During the second label application phase 164, the movable memberdecelerates whilst continuing to move towards the second position. During the label application phase, the take-up spool support continues to accelerate. The rate of deceleration of the movable member is equal to the rate of acceleration of the take-up spool support. The net effect of this is that the speed of the web at the label peeling beak is maintained at the first target speed 168. However, the rate of deceleration of the movable member may be different to the rate of acceleration of the take-up spool support. In some embodiments, when the label stock reaches the first target speed 168, the movable member may be stationary. Upon application of the second label to the second target item, the second deceleration phase 166 commences. Upon commencement of the second deceleration phase 166,the take-up spool support continues to accelerate before decelerating and the movablemember continues to decelerate while moving towards the second position beforeaccelerating towards the first position. The rate of deceleration and acceleration of the movable member in the second deceleration phase 166 is greater than the rate of deceleration of the movable member in the second label application phase 164. The final rate of acceleration of the movable member towards the first position is less than the rate of deceleration of the movable member while moving towards the second position. This is to account for the commencement of the deceleration of the take-up spool support. Once the label stock reaches the second target speed 170, the second deceleration phase 166 is complete. 69775951-1 Once the second deceleration phase 170 is complete, a reset phase 172 begins. In thereset phase 172, the take-up spool support continues to decelerate, and the movablemember decelerates while continuing to move towards the first position. In some embodiments, the take-up spool support may begin to decelerate upon commencement of the second deceleration phase 166 or the reset phase 172. Upon completion of the reset phase 172, the speed of the take-up spool support, the movable member, and the label stock is zero. As can be seen from Figure 15b, the speed of the label stock oscillates between the first target speed 168 and the second target speed 170. As can be seen from the take-up spool speed plot 146, the take-up spool does not reach the first target speed 168. The label stock is able to accelerate to the first target speed by virtue of the additional acceleration that is provided by the movable member. During use, the amount of web held on the take-up spool support 12 increases. This increases the diameter of the web held on the take-up spool support 12. Therefore, as the amount of web held on the take-up spool support 12 increases, a speed of the webdownstream of the take-up spool support 12 increases for a given angular speed of thetake-up spool support. The diameter of the web is calculated by measuring the linearmotion of the web using data received from the third roller 26, which is provided with anencoder, and comparing this to the angular motion of the take-up spool support 12. Thisallows an angular speed of the take-up spool support 12 for a given web speed to bedetermined. It will be understood that where the motor 14 is controlled to cause the webto advance, position control signals for the motor 14 should be generated based upon the diameter of the take-up spool. It will be appreciated that the above label applications described with reference to Figures 13a to 15c represent three example label applications. In other label applications, the motion profiles of the movable member, the take-up spool support, and the label stock may take forms other than those shown in Figures 13a to 15c. Indeed, in label applicators which do not include a movable member, the entire label application may be driven by the take-up spool support. It will be understood that a label applicator having a higher peak labelling speed (and associated label acceleration 69775951-1 requirement) may include a movable whereas a label applicator having a lower peak labelling speed (and associated label acceleration requirement) may omit a movable member, in order to reduce overall cost. As described above, the motor 14 configured to drive the take up spool support 12 may be a stepper motor. A motor controller 88 for the motor 55 is described above. The motor14 may also be controlled using stall-prevention techniques. The motor 14 is controlledin such a way by a motor control system 500, as illustrated in Figure 17. The motor control system 500 may be referred to as a stall-prevention system. The motor control system 500 comprises a motion controller 502. The motion controller 502 receives a product detection signal 503 from a product detector or other trigger (not shown) and generates (after a predetermined delay) a plurality of position control signals 504. The plurality of position control signals 504 are provided to a motor controller 506. The motor controller 506 is configured to generate a plurality of motor control signals 508 which are provided to a motor driver 510. The motor control signals 508 cause a magnetic field to be generated by windings of the stepper motor, the magnetic field having an orientation. As described in more detail below, the motor control signals 508 thus determine an angle to which the shaft of the motor should be rotated. The motor driver 510 converts the motor control signals 508 into suitable control signals for transistors which control the currents flowing in windings of the motor 14. An encoder 512 is connected to an output shaft of the motor 14, and is configured to generate an output signal 516 which is indicative of the angular position of the output shaft of the motor 14. The encoder output signal 516 is provided to the motor controller 506. The angular position of the output shaft of motor 14 may be measured relative to stator windings of the motor, or some other fixed position of a housing of the stepper motor. The encoder 512 may, for example, be arranged to generate 16384 output events during a full revolution of the output shaft of the motor 14. The encoder 512 may suitably be an absolute position encoder. While a particular form of encoder is described, it will be appreciated that any sensor configured to generate a signal indicative of an angular position of an output shaft of the stepper motor may be used. The motor controller 506 generates control signals 508 configured to set the coil currents in each of the motor windings so as to cause a magnetic field generated by the windings 69775951-1 of the motor to advance to a desired corresponding to a desired motor position (e.g. a micro-step position). The motor driver 510 may be controlled via a serial bus that allows the coil currents of the motor to be set directly, rather than simply receiving “step” signals. The motor control signals 508 may comprise a plurality of signal components (e.g. one for each winding of the motor). The motor control signals 508 may be updated frequently to provide a sequence of movement instructions to the motor, each movement instruction being based on a corresponding one of the plurality of position control signals 504 provided to the motor controller. In this way, the motor 14 can be caused to move from an initial position to a final position, via multiple intermediate positions, in a stepwise manner. Controlling the motor in this way allows the position of the motor, and therefore of the take up spool support, to follow a desired motion profile during application of a label on to a target item. The desired motion profile may include one or more acceleration phases, and one or more deceleration phases. The desired motion profile may be based on the target motor position. The operation of the motor controller 506 is described in more detail below with reference to Figure 20.Figure 18 illustrates the stepper motor driver 510 which is arranged to drive the steppermotor 14. The stepper motor 14 is (in this embodiment) a two-phase bipolar stepper motor having two phases 14A, 14B, shown schematically at 90 degrees to one another. Each of the phases 14A, 14B may comprise multiple windings. The stepper motor driver 510 comprises a stepper motor controller 520, which receives as inputs the motor control signals 508, and generates as outputs transistor control signals 521a-521h. The stepper motor driver 510 further comprises four power transistors 522a to 522d arranged in series pairs (522a and 522b, 522c and 522d), each pair having an intermediate node 524a, 524b between the two transistors of that pair. The two pairs of transistors are arranged in parallel between a DC power supply 526 and a ground connection 528. Each pair of transistors comprises an upper transistor 522a, 522c and a lower transistor 522b, 522d which are arranged to provide two parallel connections between the DC power supply 526 and the ground connection 528. As is common-place in PWM motor drives, free-wheel diodes may be associated with each of the transistors 522a-522d, allowing current to continue flowing in the windings when the transistors 69775951-1 522a-522d are switched off. It will be that there are many modes of operation of a full bridge current controller (e.g. ‘fast’, ‘slow’, and ‘mixed’ current decay modes) known in the art in which the transistors are switched in various sequences to achieve a desired motor current response under the control of a controller. The intermediate nodes 524a, 524b are each connected to a respective end of the windings of the first phase 14A of the motor 14. In operation each of the transistors 522a to 522d is controlled by a respective one of the output signals 521a to 521d so as to cause the first phase 14A of the motor 14 to be energised in accordance with the desired winding current level. It will be appreciated that the first phase 14A can be energised in two directions. It will further be appreciated that the first phase 14A may comprise several windings, some of which may be arranged in opposing directions. The current flowing through the windings of the first phase 14A returns through one ofthe lower transistors 522b, 522d, via a low value shunt resistor 530 to the groundconnection 528. The use of a low value shunt resistor allows several amps of motor winding current to flow without causing significant losses in the resistor. The value of the shunt resistor determines the level of current which will be caused to flow in the motor windings for each value of the motor control signal 508 specified to the stepper motorcontroller 520. The low value shunt resistor 530 may, for example be, a resistor havinga resistance of around 0.04 ohm. The voltage developed across the resistor 530 isproportional to the current flowing through the windings of the first phase 14A, accordingto Ohm’s law. The voltage developed across the resistor 530 is monitored by the steppermotor controller 520, for example by being provided to a comparator within the controller 520 (not shown) where it is compared with a desired current level. The stepper motor controller 520 may be configured to compare a voltage developed across the resistor530 with different reference voltages based upon a sensitivity setting. Thus, for a givensensitivity setting, the choice of resistor 530 may determine the maximum current level(Ipk), and thus level of current which will be caused to flow in the motor windings for each value of the motor control signal 508 specified to the stepper motor controller 520. The second phase 14B is driven by a similar arrangement of transistors (not shown) to that described as driving the first phase 14A, controlled by output signals 521e to 521h. 69775951-1The stepper motor 14 may suitably be a two-phase stepper motor having 200 fullsteps per revolution, each full step corresponding to an angular movement of the output shaft of the motor of 1.8 degrees. It will be understood that in conventional arrangements, a stepper motor controller may be provided with step and direction control signals, and be arranged to internally determine the current magnitude and field orientation required to effect stepper motor movements as required. However, in order to mitigate the risk of stalling, the stepper motor controller 520 is arranged to control the commutation and switching of the transistors 522 which are connected to the motor windings, so as to effect current magnitude and field angle values in accordance with motor control signals 508 specified by the motor controller 506. As illustrated in Figure 19, a torque 540 generated by a stepper motor depends upon a field angle 542 formed between the magnetic field of the rotor and the magnetic field generated by the energised motor windings. In Figure 19, the x-axis shows field angle 542, and the y-axis 544 shows a torque coefficient. The torque coefficient illustrated at each point indicates the torque that is generated as a proportion of the maximum available torque (for a given winding current) at the particular field angle. Where a stepper motor having a full step angle of 1.8 degrees is used (i.e. having 200 full steps per revolution), as in this example, an electrical angle of 90 degrees corresponds to a physical angle of 1.8 degrees. The generated torque is, therefore, at a maximum 546 when a physical angle of 1.8 degrees is formed between the magnetic field vector and the rotor field position. It is noted that where the angular position of the rotor field, and the direction of the stator field are discussed, what is meant is that there is a nominal position of the rotor and a nominal position of the stator field, and that the relative position between these two positions varies according to some relationship. The angular offset between the nominal position of the rotor and the nominal position of the stator field may be referred to as the field angle (or torque angle). It will further be appreciated that in a stepper motor the rotor is generally configured such that there are many effectively identical angular positions in terms of magnetic and electrical performance, which may correspond to a plurality of different actual angular positions of the rotor shaft with respect to the stator (and therefore with respect to the 69775951-1 motor housing). As such, depending on initial position of a rotor, when a stepper motor is energised, the rotor may move to the closest one of several (e.g.50) distinct angular positions. Similarly, the stator windings of the motor are typically arranged so as to have a number of windings which have different fixed angular positions. The magnetic field generated at any point in time can be represented by a vector which is based upon the relative field strengths generated by a number of windings (e.g. by each of two adjacent windings). For example, if two adjacent windings are energized to the same level, the field vector will be midway between the two windings. However, if one winding is fully energized and the adjacent winding is not energized, the field vector will be aligned with the energized winding. Again, it will be appreciated that there may be repeated windings within a motor and as such, when referring to a field vector position, it is meant to refer to the position of that field vector with reference to each set of windings. As illustrated in Figure 19, the generated torque 540 for a stepper motor is at a maximum 546 when a physical angle of 1.8 degrees is formed between the magnetic field vector and the rotor field position. After this point, the torque generated decreases for every angular increase (until the next cycle begins). It can be understood, therefore, that for any given current angular position of a stepper motor (i.e.0 degrees on the x-axis), a motor control signal 508 will cause a torque to be generated, the magnitude of which depends on the field angle. It will further be understood that if the motor control signal 508 results in a field angle of greater than 1.8 degrees (physical), then a negative torque gradient will be experienced. It has been realised that it is desirable to control the motor to operate only in a field angle region 148 which has an angle of 0 to 1.8 degrees (physical), or alternatively 0 to 90 degrees (electrical). It will be appreciated, of course, that while only positive angles are shown on the plot of Figure 19, the torque-angle characteristic is periodic (period 360 degrees (electrical), and that operation in a negative direction is also possible. As such, it is alsodesirable to limit operation of the motor to a field angle region of -1.8 to +1.8 degrees(physical), or alternatively -90 to +90 degrees (electrical).Operating beyond this region (e.g. with a physical field angle of greater than ±1.8 degrees) can result in a stall condition becoming likely, and loss of rotational control. This is because, if operating beyond the maximum torque point 546, the further the motor 69775951-1 rotates, the less the torque exerted on becomes, which can result in instabilitywhich is likely to then lead to a stall.In order to control the motor in this way, as shown in Figure 17, the motor controller 506 is arranged to receive, as an input, a signal 516 indicative of an angular position of an output shaft of the stepper motor from the encoder 512. The motor controller 506 then generates motor control signals 508 which are provided to the stepper motor controller 520 which in turn causes the windings of the stepper motor to be energised so as to cause the stator field to rotate to a position which will cause the rotor to move in the desired way. However, rather than simply generating motor control signals 508 based on the position control signal 504, the motor controller also considers the encoder signal 516, and generates the motor control signals 508 such that the magnetic field generated by windings of the stepper motor has a field angle that does not exceed a predetermined maximum value. The predetermined maximum value may be determined based on a characteristic of the stepper motor, and may, for example may correspond to ± one full step (e.g. ±1.8 degrees, for a device having 200 steps / revolution) at a native resolution of the stepper motor, which value would correspond to the maximum torque point 546 illustrated inFigure 19. During an acceleration, the field will typically lead the actual rotor position,resulting in a positive field angle. During a deceleration, the field will typically trail the actual rotor position, resulting in a negative field angle. During oscillations, either a positive or negative field angle is possible. By controlling the stepper motor 14 in this way, i.e. by providing accurate information relating to the angular position of the output shaft (and thus the rotor) of the stepper motor 14, it is possible to achieve many of the benefits conventionally associated with stepper motors (e.g. high torque output, low-cost, and high-speed operation). Moreover, by providing accurate positional information, and controlling the stator field based upon this information, there is no risk that a stepper motor will stall if the experienced load is greater than the maximum torque capacity. Rather than the motor stalling, the stator field can simply be controlled so as to rotate to an angle which allows the maximum torque to be provided. Indeed, by controlling the motor to operate with a field angle that is equal to the predetermined maximum value, when the motor is required to work the hardest, the maximum possible torque is generated. 69775951-1Figure 20 is a flow chart which processing carried out by the motor controlsystem 500. The process begins at step S0, when a detection signal is received from a trigger sensor (not shown). Processing then passes to step S1 where the motion controller 502 generates a position control signal 504. The position control signal defines a target position for the motor shaft to which the motor should be rotated at a corresponding time to cause a label to be moved. The position control signal is passed to the motor controller 506. At step S2, which can be carried out parallel with step S1, the motor controller 506 also receives the encoder signal 516 from the encoder 512. The encoder signal 516 comprises a signal (or data) indicative of an angular position of the output shaft of the stepper motor 14. At step S3 the motor controller compares the target position specified by the position control signal 504 with the data indicative of an angular position of the output shaft of the stepper motor 14 (e.g. the encoder signal 516), and determines if an angular difference between the target position (or an orientation of a magnetic field of the motor corresponding to the target position) with the encoder signal 516 (i.e. the data indicative of an angular position of an output shaft of the stepper motor) is greater than the predetermined maximum value. If this angular difference between the target position and the encoder signal 516 is less than or equal to the predetermined maximum value, processing passes to step S4, where the motor controller 506 generates a motor controlsignal 508 corresponding to the target position specified by the position control signal504. On the other hand, if the angular difference between the target position and the encoder signal 516 is greater than the predetermined maximum value, processing passes to step S5. A position control signal that would result in a field angle that is greater than the predetermined maximum value may be referred to as an excess field angle request. At step S5 the motor controller 506 modifies the position control signal 508 so as to generate a modified position control signal. The modified position control signal may specify a modified target position that corresponds to an angular position that is the predetermined maximum value from the current motor position, as represented by the encoder signal 516. 69775951-1 Once such a modified target position been generated, processing passes to step S4, where the motor controller 506 generates a motor control signal 508 based on the position control signal 504, or the modified position control signal, corresponding to the target position, or the modified target position, respectively.Processing then returns to step S1, where a new position control signal is generated. Ifa motion profile is complete, a new target position may be the same as a previous target position, and no further movement may be required, with the motor becoming stationary.The process described above with reference to Figure 20 may be repeated at apredetermined frequency, e.g. 20 kHz. That is, an updated target position may be generated by the motion controller (step S1) every 50 μs, with updated encoder signals obtained (step S2), a comparison made (step S3) and suitable control signals provided to the motor (steps S4 / S5) at the same rate. The motion controller 502 can generate a motion profile in this way so as to cause a label web to be accelerated from rest to a target labelling speed. A label can then be dispensed, and the web decelerated back to rest. Alternatively, multiple labels may be dispensed in succession, without the web coming to a complete stop. In either case, the motion controller 502 is configured to generate a series of position control signals specifying a corresponding series of target position values. The motor controller 106 processes these signals, and causes the motor 14 to execute the motion profile as closely as possible, but without stalling. A motion profile of this sort may typically comprise many 1000s (i.e. a plurality) of position control signals, each being generatedat a respective time, and defining a respective target position for the motor shaft. It willbe understood that the number of position control signals required to dispense a single label will vary depending upon label speed, label length, and system gearing characteristics. During design of a particular labelling machine, a theoretical maximum acceleration capacity will be determined. That is, for a particular mechanical arrangement, and targetspecification (e.g. product speed of 1000 mm / s, and acceleration distance of 3 mm) amotor may be selected that has sufficient torque capacity to deliver the required acceleration. However, in practice, it will be understood that during label movements the actual label speed at any moment may fluctuate due to various factors (e.g. non- linearities in the torque profile generated by the motor, compliance of various system 69775951-1 components leading to resonance). may result in some temporary deviation between the desired motion profile (as generated by the motion controller 502) and the actual motion of the label web (as indicated by the encoder 512). If such deviation results in the desired motor position extending too far ahead of the action position at any moment, then there is a risk of a stall. The stall-prevention system described above avoids this occurring, since no demanded position will be provided to the motor driver that extends beyond the capability of the motor. It will be understood that it may be possible to reduce the risk of stalls in an alternative way by increasing the motor size (e.g. by providing 50 % additional torque capacity). However, such an arrangement will be inefficient, and unnecessarily costly. The stall-prevention behaviour described herein “limits” or “clips” the instantaneous position demanded by the motor controller 506. As described above, this tends to be a short term response to transient fluctuations in movement. The nature of such transient effects is that a momentary shortfall in position will likely be corrected in a subsequent step. It will be understood, however, that if a demanded motion profile is consistently in excess of the capabilities of a motor, then the motor will never “catch-up”. Such behaviour can result in system underperformance. In order to monitor system behaviour an indication of any excess field angle requests leading to clipping or target position limiting behaviour may be provided by the motor controller 506 to the motion controller 502 (or another system controller). A feedback signal may be provided that indicates that an excess field angle was detected (i.e. that a desired position signal could not be achieved), and that a modified position signal was generated (i.e. each time step S5 is triggered). The motion controller 502 may monitor such a feedback signal, and take one or more actions depending on the scale of any deviations from expected behaviour. That is, the motion controller may monitor data indicative of the generation of the modified position control signal. The motion controller 502 may for example count any deviations throughout a label feed. It will be understood that a label feed operation will comprise many passes through the control loop (i.e. S1-S6). It will of course be understood that if a discrepancy is generated in a first control loop iteration, but no discrepancy is generated in a following loop iteration, then the system will be understood to have substantially achieved the desired movement, and the discrepancy was simply a result of a transient event. On the other 69775951-1 hand, if successive movement be achieved, it will be understood that a systematic problem may exist. The motion controller 502 may be configured to generate a warning in such circumstances. The motion controller 502 may generate a variety of different warnings depending on the severity of any detected discrepancy. For example, where a predetermined number of position control signals cannot be fully executed during a label movement (e.g. 1% of demanded movements), and / or where the magnitude of a discrepancy exceeds a predetermined magnitude threshold (e.g. initial position demand is >200 degrees (electrical) from an actual motor position) a warning signal or fault condition may be generated. That is, where data indicative of the modified position control signal exceeds a predetermined threshold a fault condition may be generated. The warning signal may be intended to alert the user to a possible system issue. Data indicative of the generation of the modified position control signal may comprise data indicative of a proportion of position control signals that are modified in some way, a duration for which torque limiting behaviour is active, and / or a magnitude of excess field angle requests (e.g. a physical difference between the target position and the actual position). On the other hand, where a label motion cannot be executed at all (e.g. the motor cannot catch-up with the demanded motion profile), a system fault may be raised, and the motion profile paused. Such a fault may, for example, cause a production line to stop, and will require attention from an operator. Such a fault may be caused by an obstruction of some sort (e.g. machine malfunction, label web jam), and may be identified by a persistent and / or increasing magnitude of excess field angle requests. In this way, it is possible for the motion controller 502 to distinguish between a transient event, or series of temporary fluctuations, which may themselves be indicative of some underlying fault, and a more serious problem which requires immediate attention. The motion controller may thus be configured to generate a first fault condition (e.g. user warning) if the data indicative of the modified position control signal satisfies a first condition (e.g. minor and / or temporary excess field angle requests), and generate a second fault condition (e.g. halt labelling operations) if the data indicative of the modified position control signal satisfies a second condition (e.g. major and / or sustained excess field angle requests). 69775951-1 In some circumstances excess field data may be used to identify or diagnose certain operational situations or anomalies. Such data could be used in combination with other system data to raise an appropriate fault condition or warning. For example, web movement data generated by a web encoder could be compared with take-up spool rotation data, and excess field angle events, to indicate that a motor was overloaded and not able to deliver a target acceleration profile. For example, an angular error between the target (angular) position and the actual (angular) position reported by the encoder of greater than 5 degrees may be used to trigger a warning or identify an anomaly. Alternatively, or additionally, a linear error between the target (linear) position and the actual (linear) position reported by the encoder of greater than 5 mm may be used to trigger a warning or identify an anomaly. It will be understood that a relationship between angular and linear position may vary during the course of labelling machine operation where the diameter of the used web wound onto the take-up spool support increases. It has been described above that a motion profile can be accomplished by providing a series of position control signals that are regularly spaced in time (e.g. every 50 μs). In alternative embodiments a similar effect can be achieved by providing position control signals that are regularly spaced in terms or angular rotation (or even linear motion of a label), with the timing varied in order to control acceleration. In such an arrangement, the process described above with reference to Figure 6 may be modified such that a targettime associated with a position control signal is modified at step S5, rather than a targetposition. For example, a time at which a next position control signal is delivered can bealtered (e.g. delayed) in order to allow the motor to catch-up. Further, in some cases itmay be useful to reverse a direction of a step signal, or to include additional intermediatestep positions. In such an arrangement, an expected difference between an orientationof a magnetic field of the motor corresponding to the modified position control signal and the data indicative of an angular position of an output shaft of the stepper motor would not exceed the predetermined maximum value. It would be understood that this modification would require that an incremental step size is less than or equal to a fullstep (e.g. 1 / 32nd step increments), since otherwise a static motor could never beaccelerated from rest. It has been described above that the signal 516 is received from the encoder 512 at regular intervals. It will be understood, however, that during motion, the processing of 69775951-1 the encoder signal 516 may take a amount of time. Moreover, the processing required to compare the encoder signal 516 with a position control signal 504 (i.e. target position), and to generate an appropriate motor control signal 508 may also take a finite amount of time. During this processing time the motor shaft, if it is already in motion, will have covered some distance. As such, compensation may be used to compensate for motor rotation when receiving encoder signals 516. Processing step S2 may therefore include a further compensation process. The compensation may be performed by a compensator 517 (shown as an optional component in Figure 3). The compensator 517 may, for example, receive data indicative of a rotational speed of the output shaft of the stepper motor, e.g. via a motor speed signal 518 received from the motion controller 502. Alternatively, the compensator 517 may derive the data indicative of a rotational speedof the output shaft of the stepper motor from signals received from the encoder 512. Forexample, the compensator 517 may generate speed signal 518 from a plurality of successive signals received from the encoder 512. It will be understood that such processing may itself add a further delay, which may in turn benefit from further compensation. The compensator 517 may interpret the encoder signal 516 in view of the motor speed signal 518, and a known time delay associated with the required processing. In this way, compensator 517 may generate a compensated position signal 519 that is derived from the encoder signal 516, and motor speed signal 518. By using an actual position signal (i.e. the compensated encoder signal 519) generated in this way, it is possible to mitigate or allow for latency that could otherwise be present in the system due to processing delays. It will further be understood that references herein to an encoder signal 516 may refer to a suitable compensated encoder signal 519. It will be understood that the motor speed may be observed or estimated in any convenient way. For example, the speed may be estimated based on the last two position control signals that were provided to the motor controller 504. Alternatively, the speed may be estimated based on an immediately preceding motor control signal 508 and a next motor control signal (i.e. a motor control signal that has not yet been executed). Alternatively, the motor speed signal may be derived from previous encoder signals 516. The compensator 517 may be implemented as a separate component (e.g. software sub- routine), or as part of the motion controller 502, or motor controller 504. 69775951-1It has been described above that stall- may be used where the motor cannoteffectively keep up with a desired motion profile. It will of course be understood that deviations in actual and desired position can occur both under acceleration and under deceleration as well as during substantially constant speed motion. The processing described herein may be applied in any of the circumstances. As such the comparison at step S3 between a target position and an actual (or encoder) position may be based on a magnitude of difference rather than a directional difference. It will be understood of course that any compensation of the encoder signal 116 should take into account the direction of travel.Figure 21 shows a small part of a motion profile 550 executed by the motor controlsystem 500 during a label dispensing operation. The x-axis 552 shows time in steps t0-t8. At each of the indicated times, a new target position P0 – P8, as illustrated on the lefthand y-axis 554, is specified by the motion controller 502 to the motor controller 506.Each of the target positions P0 – P8 defines a position control signal 504. At each of thetimes t0-t8 a respective encoder position E0 – E8, as illustrated on the right-hand axes556, is received by the motor controller 506 from the encoder 512. Each of the encoderpositions E0 – E8 defines an encoder signal 516 (which may be compensated asappropriate). At each time t0-t8 a new target position is specified. At each time t0-t8, the distance between the target position P0-P8 and the corresponding encoder position E0-E8 is assessed (as described with the reference to step S3). Where the difference is less than or equal to the maximum permitted field angle 558, the respective position control signal is executed by the motor controller 506, and a corresponding motor control signal 508 is generated. On the other hand, where the difference in position exceeds the maximum permitted field angle 558 (i.e. an excess field angle request), a modified target position is generated, as described above with reference to step S5 of Figure 20. In the illustration of Figure 21, the target position can be seen to exceed the maximum field angle at times t2, t4, t5, t6, and t7. At each of these times, a modified position control signal 104’ is generated, resulting in modified target positions P2’, P4’, P5’, P6’, and P7’ being generated. It can be seen that while approximately half of the requested target positions in the motion profile segment illustrated exceed the maximum permitted field angle 158, the 69775951-1 motion profile is substantially executed That is, at both times t0 and t8 (i.e. at both the start and end of the motion profile segment) the required movement has beenexecuted. As such the motor can be seen to have caught-up during the period of themotion profile.It will of course be appreciated that the illustration of Figure 21 is a simplified exampleintended to illustrate the control process, and does not correspond precisely to a real motion profile. Moreover, it will be understood that the distances shown in the y-axis are somewhat exaggerated with an offset being introduced between the encoder and target position signals so as to aid understanding. In practice a motion profile may be generated upon receipt of a product detection signal, or other trigger signal, received by a controller of the labelling machine. The motion profile may cause the take-up spool support 12, driven by the motor 14, to accelerate from rest to a labelling speed, which may be determined based upon the speed of a product moving past a labelling machine. The labelling machine may dispense the label while the web is moving at a substantially constant speed, and then decelerate once the label has been applied to the product. The labelling machine may then await a further trigger signal. A particular geometry and configuration of stepper motor has been described above. It will of course be appreciated that alternative stepper motor geometries and configurations may be used. In such circumstances a different maximum field angle, either in terms of physical angle or electrical angle, may be required. However in each case, where a stepper motor is used having a periodic electrical characteristic, a maximum angle will exist beyond which a generated torque will begin to decrease (e.g. as illustrated in Figure 5). As such, while the value of the maximum field angle may vary, the existence of the maximum field angle may be relevant to a number of different stepper motor geometries and configurations.It will also be appreciated that the torque characteristics shown in Figure 19 is anidealised example of a torque characteristics for a particular form of motor. A real torque profile may deviate from this example in a number of ways. Of course, it will be appreciated that the use of a stepper motor also allows the use of conventional open-loop stepper motor control (which may be referred to as stepping mode, or micro-stepping mode) when beneficial. Indeed, the stall-prevention system 69775951-1 described above may allow the motor to controlled as for a conventionally controlled stepper motor at most times, with the stall-prevention behaviour only being activated in exceptional circumstances (e.g. if a high resistance was encountered). In labelling machines, such as the ones depicted in Figures 1 and 2, the speed of the label stock 18 is primarily controlled by the motor that is coupled to the take up spool. In use, the speed of the web of the label stock 18 varies. Each time a target item passes the labelling machine, the web speed increases (following a delay, discussed in more detail below) to match the target item speed and a label is applied to the target item. The web speed then decreases to prevent a subsequent label passing the label peeling beak. This requires repeated acceleration and deceleration of the web. In some embodiments it has been discovered that it may be beneficial to supplement the acceleration and deceleration of the web that is provided by the motor of the take-up spool support 12 by providing a movable member 50. The motor 55 may be controlled to move the movable member 50 by a motor control system that is substantially similar to the motor control system 500 described above withreference to Figure 17 in connection with the motor 14. That is, the motor 55 may be astepper motor, and may be controlled by a stall-prevention system. The movable member is thus another example of a component of the labelling machine that causes movement of a portion of the web extending between the supply spool support and the take up spool support. A motion profile may be provided to the motor controller 506 which generates and modifies motor control signals for the motor 55 in a similar way to that described above. That is, the motor controller 88 described with reference to Figure 12 may be implemented as described with reference to Figure 17. In some configurations only one of the motors 14, 55 may be controlled by a stall- prevention system of the sort described above. That is, in some circumstances one of the motors 14, 55 may be controlled in a conventional open-loop manner, or alternatively in a closed loop position-controlled manner. Further still, in some circumstances one of the motors may be an alternative type of motor, such as, for example, a DC servo motor. It will be appreciated, however, that the operation of a stall-prevention system may be advantageous when applied to one or more of the motors 14, 55. 69775951-1 It will be understood that when motors are controlled in this way, a motion profile may be generated by the motion controller 502 which in turn generates a respective motion profile for each of the motors 14, 55. A respective position control signal 504 may be generated by the motion controller 502 for each of the motors 14, 55. The motion controller 502 may determine relative accelerations and decelerations of the two motors 14, 55, so as to achieve an overall desired label motion profile, which is within the acceleration capabilities of each of the component parts of the system. It will further be appreciated that the labelling machine may comprise one or more further components that cause movement of a portion of the web extending between the supply spool support and the take up spool support and which can be controlled by a stall- prevention system of the sort described herein. The labelling machines described above generally rely upon the accurate control of a take-up spool support by a motor 14 to advance the label web. In an alternative configuration, a nip-drive may be used. Such an arrangement is shown schematically inFigure 22. In particular, Figure 22 shows a labelling machine 400. The labelling machine400 is generally similar to the labelling machine shown in Figures 1 and 3 in that it doesnot comprise a printer. However, a printer may be provided. The labelling machine 400 differs from the labelling machine shown in Figures 1 and 3 in that the labelling machine 400 comprises a roller 490, a drive roller 492 and a nip roller 494. In the embodiment of Figure 22, a motor (not shown) controls the drive roller 492. The nip roller 494 is configured to press against the drive roller 492, trapping the label stock 18 therebetween. Accurate control of the position of the label stock 18, including the advance of the web, is achieved by rotating the drive roller 492, by the associated motor. It will be understood that since the drive roller 492 has a fixed diameter, there is no need for motor control signals to be modified based upon the diameter of the take-up spool. The take up spool support may also be driven to rotate, so as to accumulate the used web. The take-up spool support may be driven by the same motor that is used to control the drive roller (e.g. via a slipping clutch), or via a dedicated motor. It will be understood that where accurate positional control of the web is achieved by the drive roller 492, rather than the take-up spool support, the control requirements for the take- up spool support are relaxed. While not shown, a moveable element similar to the dancing arm 28 may be provided in the web path 20 between the nip roller 492 and take 69775951-1 up spool support 12 to accommodate in web tension. The roller 490 is a simple idle roller, although could also incorporate an encoder to measure web motion. The motor connected to the drive roller 492 may be controlled by a stall-prevention system of the sort described above, by a control system 500 as illustrated in Figure 17. That is, the motor may be operated in a position controller manner, based on a position control signal generated by a motion controller, with an encoder signal used to modify the requested position, if an excess field angle request is encountered. The stall prevention system described herein has been described as being performed by a control system 500. It will be understood that the various “controllers”, or other processing components, described in the context of this control system (e.g. motion controller 502, motor controller 504, compensator 517) may, in fact, comprise parts of a common controller and / or may be configured as software sub-routines operating on a controller. Such a controller may also be configured to control other aspects of the labelling machine (e.g. a supply spool brake). On the other hand, one or more separate function specific controllers may be provided. A controller may comprise a processor, configured to process data and to generate control signals.It will be appreciated that embodiments disclosed herein can be implemented in anyconvenient form. For example, embodiments disclosed herein may be implemented byappropriate computer programs which may be carried on appropriate carrier media which may be tangible carrier media (e.g. disks) or intangible carrier media (e.g.communications signals). Embodiments disclosed herein may also be implementedusing suitable apparatus which may take the form of programmable computers running computer programs arranged to implement the embodiments disclosed herein. Embodiments of the subject matter and the operations described in this specification can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware. Embodiments of the subject matter described in this specification can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions, encoded on computer storage medium for execution by, or to control the operation of, data processing apparatus. Alternatively or in addition, the program instructions can be encoded on an artificially-generated propagated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal, that is generated to 69775951-1 encode information for transmission to receiver apparatus for execution by a data processing apparatus. A computer storage medium can be, or be included in, a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination of one or more of them. Moreover, while a computer storage medium is not a propagated signal, a computer storage medium can be a source or destination of computer program instructions encoded in an artificially-generated propagated signal. The computer storage medium can also be, or be included in, one or more separate physical components or media (e.g., multiple CDs, disks, or other storage devices).The operations described in this specification and being performed by a controller canbe implemented as operations performed by a processor on data stored on one or more computer-readable storage devices or received from other sources. The term “processor” encompasses all kinds of apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, a system on a chip, or multiple ones, or combinations, of the foregoing. The apparatus can include special purpose reprogrammable logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit). The apparatus can also include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, a cross-platform runtime environment, a virtual machine, or a combination of one or more of them. The apparatus and execution environment can realize various different computing model infrastructures, such as web services, distributed computing and grid computing infrastructures. Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. Devices suitable for storing computer program instructions and data include all forms of computer-readable media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD- 69775951-1 ROM disks. The processor and the can be supplemented by, or incorporatedin, special purpose logic circuitry and fiber-optic platform for faster data transfer remotely.To provide for interaction with a user, embodiments of the subject matter described in this specification can be implemented on a computer having a display device, e.g., aCRT (cathode ray tube) or LCD (liquid crystal display) monitor including audio, fordisplaying information (e.g. an indication and / or alert) to the user. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback. Although the disclosure has been described in terms of preferred embodiments as set forth above, it should be understood that these embodiments are illustrative only andthat the claims are not limited to those embodiments. The skilled person will be able tomake modifications and alternatives in view of the disclosure which are contemplated as falling within the scope of the appended claims. Each feature disclosed or illustrated in the present specification may be incorporated in the disclosure, whether alone or in any appropriate combination with any other feature disclosed or illustrated herein. 69775951-1

Claims

CLAIMS:

1. A labelling machine comprising: a supply spool support for supporting a supply spool comprising label stock, the label stock comprising a web and a plurality of labels attached to the web; atake-up spool support configured to take up a portion of the web;a motor configured to advance the web along a web path from the supply spool support towards the take up spool support; a labelling peel beak located along the web path and configured to peel the labels from the web as the web passes the labelling peel beak; a movable member, the movable member configured to contact a portion of theweb and define a portion of the web path between the labelling peel beak and the take-up spool support, wherein movement of the moveable member changes a length of theweb path, and wherein a position of the movable member is controllable via an actuator; and a controller configured to: control the actuator to adjust the position of the movable member; andcontrol a position of the motor.

2. The labelling machine according to claim 1, wherein the controller beingconfigured to control the position of movable member and the position of the motorcomprises the controller being configured to: control the motor and the movable member to adjust a speed of the web passing the labelling peel beak.

3. The labelling machine of claim 2, wherein the controller being configured tocontrol the motor and the movable member to adjust a speed of the web passing the labelling peel beak comprises the controller being configured to: control the motor and the movable member to accelerate or decelerate the webpassing the labelling peel beak to a first target speed or to a second target speed.

4. The labelling machine of claim 3, wherein the first target speed and the secondtarget speed are predetermined. 69775951-15. The labelling machine of claim 3 4, wherein the first target speed is basedon a signal indicative of a speed of a target item to which a label is to be applied, and wherein the second target speed is zero.

6. The labelling machine according to any of claims 3 to 5, wherein the controllerbeing configured to control the motor and movable member to accelerate or deceleratethe web passing the labelling peel beak comprises the controller being configured to:accelerate or decelerate the motor, andaccelerate the movable member to increase or decrease the length of the webpath.

7. The labelling machine of claim 6, wherein the controller being configured toaccelerate or decelerate the motor and accelerate the movable member to increase or decrease the length of the web path comprises the controller being configured to: accelerate or decelerate the motor, and accelerate the movable member to increase or decrease the length of the web path such that the speed of the web passing the labelling peel beak oscillates between the first target speed and the second target speed.

8. The labelling machine of any of claim 3 to 7, wherein the controller is configuredto accelerate the motor and accelerate the movable member in a direction that decreasesthe length of the web path such that the speed of the web passing the labelling peel beakis maintained at the first target speed for a predetermined amount of time.

9. The labelling machine according to any of claims 6 to 8, wherein the controllerbeing configured to accelerate the motor and accelerate the movable member toincrease the length of the web path comprises the controller being configured to: determine a movable member acceleration based on data indicative of a speed of a target item and a predetermined acceleration of the motor such that the speed ofthe web at the labelling peel beak is within 1% of the speed of the target item; andaccelerate the motor at the predetermined acceleration and accelerate the movable member at the determined movable member acceleration.

10. The labelling machine according to claim 9, wherein the controller is configuredto accelerate the motor and the movable member simultaneously. 69775951-111. The labelling machine according to any preceding claim, wherein the movablemember is pivotable to increase or decrease the length of the web path.

12. The labelling machine of claim 11, wherein the movable member is pivotablebetween a first position that corresponds to a minimum length of the web path, and asecond position that corresponds to a maximum length of the web path, and wherein themovable member is operated in a range of 30 degrees and 150 degrees from the firstposition.

13. The labelling machine according to any preceding claim, wherein the movablemember comprises a roller that comprises a first axis and a second axis, the movablemember being rotatable about the first axis to support the web and being pivotable about the second axis to change the length of the web path.

14. The labelling machine according to claim 13, wherein the second axis is disposedwithin an external periphery of the roller.

15. The labelling machine of any preceding claim, further comprising a cover that iscoupled to a distal end of the movable member and to a distal end of a roller that is disposed adjacent the movable member.

16. The labelling machine according to any preceding claim, wherein the actuator isa motor.

17. The labelling machine according to claim 16, wherein the motor is a steppermotor having an output shaft coupled to the movable member, the stepper motor being arranged to vary the position of the movable member, the labelling machine further comprising: a sensor configured to generate a signal indicative of an angular position of the output shaft of the stepper motor; and wherein: the controller is configured to generate control signals for the stepper motor so as to cause a magnetic field to be generated by windings of the stepper motor, a field angle being defined between an angular position of the output shaft of the stepper motor, 69775951-1and an orientation of the generated field, the control signals being configured to cause the field angle to not exceed a predetermined maximum value.

18. The labelling machine according to claim 16 or 17, wherein the controller isconfigured to generate a target motor position based on a desired motion profile, and control the motor to rotate to the target motor position.

19. A method of operating a labelling machine, the labelling machine comprising:a supply spool support for supporting a supply spool comprising label stock, the label stock comprising a web and a plurality of labels attached to the web; a take-up spool support configured to take up a portion of the web; a motor configured to advance the web along a web path from the supply spool support towards the take up spool support; a labelling peel beak located along the web path and configured to peel the labels from the web as the web passes the labelling peel beak;a movable member, the movable member configured to contact a portion of the web anddefine a portion of the web path between the labelling peel beak and the take-up spool,wherein movement of the moveable member changes a length of the web path, and wherein a position of the movable member is controllable via an actuator; the method comprising: controlling the actuator to adjust the position of the movable member; and controlling the position of the motor.

20. The method of claim 19, wherein the method comprises adjusting a speed of theweb passing the labelling peel beak by controlling the motor and the movable member.

21. The method of claim 20, wherein the method comprises accelerating ordecelerating the web passing the labelling peel beak to a first target speed or to a second target speed by controlling the movable member and the motor.

22. The method of claim 21, wherein the first target speed and the second targetspeed are predetermined. 69775951-123. The method of claim 22, the first target speed is based on a signalindicative of a speed of a target item to which a label is to be applied, and wherein the second target speed is zero.

24. The method of any of claims 21 to 23, wherein, to accelerate or decelerate theweb passing the labelling peel beak to the first target speed or to the second target speed, the motor is accelerated or decelerated and the movable member is accelerated to increase or decrease the length of the web path.

25. The method of claim 24, wherein the motor is accelerated or decelerated and themovable member is accelerated to increase or decrease the length of the web path such that the speed of the web passing the labelling peel beak oscillates between the first target speed and the second target speed.

26. The method of any of claims 21 to 25, wherein the motor is accelerated and themovable member is accelerated in a direction that decreases the length of the web path such that the speed of the web passing the labelling peel beak is maintained at the first target speed for a predetermined amount of time.

27. The method of any of claims 24 to 26, further comprising:determining a movable member acceleration based on data indicative of a speed of a target item and a predetermined acceleration of the motor such that the speed of the web at the labelling peel beak is within 1% of the speed of the target item; accelerating the motor at the predetermined acceleration; andaccelerating the movable member at the determined movable member acceleration.

28. A labelling machine comprising: a supply spool support for supporting a supply spool comprising label stock, the label stock comprising a web and a plurality of labels attached to the web; a take-up spool support configured to take up a portion of the web; the labelling machine being configured to advance the web along a web path from the supply spool support towards the take up spool support; a labelling peel beak located along the web path and configured to peel the labels from the web as the web passes the labelling peel beak; 69775951-1a stepper motor configured to a position of a component of the labelling machine that causes movement of a portion of the web extending between the supply spool support and the take up spool support; a sensor configured to generate a signal indicative of an angular position of an output shaft of the stepper motor; and a controller configured to control the control the angular position of the stepper motor, wherein: the controller is configured to generate motor control signals for the stepper motor so as to cause a magnetic field to be generated by windings of the stepper motor, a field angle being defined between an angular position of the output shaft of the stepper motor and an orientation of the generated magnetic field, the motor control signals being configured to cause the field angle to not exceed a predetermined maximum value.

29. The labelling machine according to claim 28, wherein the controller is configured to generate a plurality of position control signals at a corresponding plurality of times, each of the position control signals defining a respective target position for the motor shaft at the corresponding time.

30. The labelling machine according to claim 29, wherein, for each of the generated position control signals, the controller is configured to compare the target position with data indicative of an angular position of an output shaft of the stepper motor, and to generate the motor control signals for the stepper motor based upon the output of the comparison.

31. The labelling machine according to claim 30, wherein the data indicative of an angular position of an output shaft of the stepper motor is generated based on: the signal indicative of an angular position of an output shaft of the stepper motor; and data indicative of a rotational speed of the output shaft of the stepper motor.

32. The labelling machine according to claim 30 or 31, wherein the controller isconfigured to: determine whether a difference between an orientation of a magnetic field of the motor corresponding to the target position and the data indicative of an angular position of an output shaft of the stepper motor exceeds the predetermined maximum value; and, 69775951-1if the difference exceeds the maximum value, generate a modified position control signal.

33. The labelling machine according to claim 32, wherein the modified position control signal corresponds to a modified target position, wherein a difference between an orientation of a magnetic field of the motor corresponding to the modified target position and the data indicative of an angular position of an output shaft of the stepper motor does not exceed the predetermined maximum value.

34. The labelling machine according to any one of claims 32 or 33, wherein the controlleris configured to generate motor control signals for the stepper motor corresponding to the target position or the modified target position.

35. The labelling machine according to claim 32, wherein if the difference is less than or equal to the predetermined maximum value, the controller is configured to generate motor control signals for the stepper motor corresponding to the target position.

36. The labelling machine according to any one of claims 32 or 33, wherein if thedifference is greater than the predetermined maximum value, the controller is configured to generate motor control signals for the stepper motor corresponding to the modified target position.

37. The labelling machine according to claim 32, wherein the modified position control signal corresponds to a delayed target position, wherein an expected difference between an orientation of a magnetic field of the motor corresponding to the delayed target position and the data indicative of an angular position of an output shaft of the stepper motor does not exceed the predetermined maximum value.

38. The labelling machine according to any one of claims 32 to 37, wherein the controlleris configured to monitor data indicative of the generation of the modified position control signal.

39. The labelling machine according to claims 38, wherein the controller is configured to generate a fault condition if the data indicative of the modified position control signal exceeds a predetermined threshold. 69775951-140. The labelling machine according to any one of claims 28 to 39, wherein the component of the labelling machine that causes movement of the portion of the web extending between the supply spool support and the take up spool support comprises the take up spool support.

41. The labelling machine according to claim 40, wherein the labelling machine is configured to advance the web along a web path from the supply spool support towards the take up spool support by causing the stepper motor to rotate, thereby causing the take up spool support to rotate.

42. The labelling machine according to claim 41, as dependent upon claim 29, or any preceding claim dependent thereon, wherein each of the plurality of position control signals corresponds to an angular position of the take up spool support, and wherein the controller is configured to cause the web to advance by providing motor control signals corresponding to the plurality of position control signals to the motor.

43. The labelling machine according to claim 42, further comprising a motion controller configured to generate the plurality of position control signals based upon a label motion profile.

44. The labelling machine according to any one of claims 28 to 39, wherein:the labelling machine further comprises a movable member; the movable member is configured to contact a portion of the web and define a portion of the web path between the labelling peel beak and the take-up spool support, movement of the moveable member changes a length of the web path; and the position of the movable member is controlled by the stepper motor.

45. The labelling machine according to claim 44, wherein the labelling machinecomprises a further motor configured to advance the web along a web path from the supply spool support towards the take up spool support.

46. The labelling machine according to claim 45, wherein the controller is configuredto control the position of movable member and the position of the motor to adjust a speed of the web passing the labelling peel beak. 69775951-147. The labelling machine according to claim 46, wherein the controller is configuredto control the further motor and the movable member to accelerate or decelerate the web passing the labelling peel beak to a first target speed or to a second target speed.

48. The labelling machine according to claim 40 and any one of claims 44 to 47,comprising: a first stepper motor configured to cause the take up spool support to rotate to advance the web along a web path from the supply spool support towards the take up spool support, and a second stepper motor configured to control the position of the movable member; wherein the controller is configured to generate a target motor position for each of the first stepper motor and the second stepper motor based on a desired motion profile, and to control the first stepper motor and the second stepper motor to rotate to the respective target motor position.

49. The labelling machine according to any one of claims 28 to 39, wherein thecomponent of the labelling machine that causes movement of the portion of the web extending between the supply spool support and the take up spool support comprises a drive roller, and wherein the motor is configured to cause the drive roller to rotate to advance the web along the web path from the supply spool support towards the take up spool support.

50. A method of operating a labelling machine, the method comprising:advancing a web along a web path, the web supporting a plurality of labels; peeling labels from the web as the web passes a labelling peel beak of thelabelling machine; controlling, by a stepper motor, a position of a component of the labelling machineto cause movement of a portion of the web along the web path, wherein the controllingcomprises: generating motor control signals for the stepper motor so as to cause a magnetic field to be generated by windings of the stepper motor, a field angle being defined between an angular position of the output shaft of the stepper motor and an orientation of the generated magnetic field, the motor control 69775951-1signals being configured to field angle to not exceed a predetermined maximum value.

51. The method of claim 50, further comprising generating a plurality of positioncontrol signals at a corresponding plurality of times, each of the position control signals defining a respective target position for the motor shaft at the corresponding time.

52. The method of claim 51, further comprising for each of the generated positioncontrol signals, comparing the target position with data indicative of an angular positionof an output shaft of the stepper motor, and generating the motor control signals for thestepper motor based upon the output of the comparison.

53. The method of claim 52, further comprising:receiving a signal indicative of an angular position of an output shaft of thestepper motor from a sensor; andgenerating the data indicative of an angular position of an output shaft of thestepper motor based on the signal indicative of an angular position of an output shaft ofthe stepper motor.

54. The method of claim 53, wherein generating the data indicative of an angularposition of an output shaft of the stepper motor is further based on data indicative of arotational speed of the output shaft of the stepper motor. 69775951-1

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