Some printers include a cutting device which can cut a print medium before or after a printing operation. The cutting device may include a cutting blade supported on a carriage to move across a print zone. By movement of the carriage across the print zone and/or movement of the print medium along a media advance path through the print zone, the cutting blade may cut in one or two linear directions, such as the X and Y directions.
The following description references the drawings, wherein
In the illustrated example, the cutting arrangement comprises a first cutter module 10 and a second cutter module 20, which are discussed in further detail below. The first and second cutter modules 10, 20 are arranged on a shaft 30 extending in a direction perpendicular to a media advance direction of a printer which is illustrated by arrow A. The media advance direction A also is referred to as Y direction, and a carriage scanning direction, perpendicular to the Y direction, also is referred to as X direction. The direction of gravity, perpendicular to both the Y and X directions, may be designated as Z direction. The first cutter module 10 also can be designated as left-hand cutter module, and the second cutter module 20 also can be designated as right-hand cutter module, wherein left and right designates the position of the cutter module as seen from the front of the printer which, in this example, is the direction opposite to the media advance direction A.
The two cutter modules 10, 20 are arranged on the shaft 30 to be independently slidable along the length of the shaft 30, e.g., along the scanning direction, wherein sliding movement of the cutter modules 10, 20 can be caused by respective first and second pulley drives 12, 22 coupled to the first and second cutter modules 10, 20 via positioners 18, 28. This allows selectively positioning the two cutter modules 10, 20 at a right-hand edge and a left-hand edge of a cutting zone downstream of a print zone of the printer, for different cutting zones of varying width and position. In the illustrated example, a cutting zone of maximum width Pmax would extend about across the width of an output platen 50, illustrated in
In the illustrated example, pulley drive 22 associated with the second or right-hand cutter module 20 extends across about 30% of the maximum cutting zone width Pmax, at the right-hand side of the cutting zone, and pulley drive 12 associated with the first or left-hand cutter module 10 extends across about 80-90% of the maximum cutting zone width Pmax, at the left-hand side of the cutting zone. The belts 14, 24 of the first and second pulley drives 12, 22 overlap and, for example, can be designed in such a way that the first and second cutter modules 10, 20 can be positioned at any left-hand and right-hand margins of a print medium which the associate printer is able to print on in the print zone.
The first and second cutter modules 10, 20 are removably coupled to the first and second pulley belts 12, 24 by respective positioners 18, 28 to be engaged with the cutter modules 10, 20. Accordingly, movement of either one of the belts 14, 24 pulls the associated cutter module 10, 20 along the shaft 3o to position the cutter modules 10, 20 on two sides of an adjustable cutting zone, for example.
The shaft 30 is coupled to a drive motor 40 via a drive gear train 42, including a number of gears, for transmitting rotation of the drive motor 40 to the shaft 30. The drive motor 40 may be a servomotor, a BLDC motor or a stepping motor or another electric motor. The drive motor 40 may be supplied and driven via supply/drive lines 44 operatively coupled to a controller (not shown) of the printer, for example.
The cutter arrangement including the drive motor 40 may be mounted in a printer chassis (not shown) via a number of brackets and supports 32, 34, 36, 38, 44.
In the illustrated example, the drive gear train 42 comprises a number of spur gears which, in the example, provide three transmission stages to transmit rotation of a toothed output shaft 41 of the drive motor 40 to shaft 30. The drive gear train 42 allows adjusting the rotation speed of the shaft 30 and transmits rotation of output shaft 41 in both a clockwise direction and a counterclockwise direction.
In the illustrated example, the shaft 30 has a polygonal cross-section, such as a hexagonal cross-section wherein other cross-sections, including a circular or noncircular, elliptic or a non-symmetrically shaped cross-section may be provided. The cutter modules 10, 20 are coupled to the shaft 30 by respective transmission rings 102, 202. In the example, the transmission rings 102, 202 engage with the outer periphery of the shaft 30 in a formfitting manner wherein, alternatively or additionally, a press fit or engagement by additional fixing elements, such as a screw, a bracket, adhesive or the like may be provided.
In the illustrated example, each cutter module 10, 20 comprises an upper module half 104, 204 and a lower module half 106, 206 which clamp the respective transmission ring 102, 202. Handle-like extensions 108, 110, 208, 210 are provided at the upper and lower module halves 104, 204 to be grabbed and pressed against each other to pivot the upper and lower module halves 108, 110, 208, 210 relative to each other to disengage the module halves from the transmission rings and unlatch the respective cutter modules 10, 20 from the transmission rings 102, 202. Accordingly, each cutter module 10, 20 can be replaced by pressing together the-handle-like extensions 108, 110, 208, 210, unlatching the cutter modules 10, 20 from the transmission rings 102, 202 and inserting another cutter module by the reverse operation.
In the example illustrated, each of the cutter modules 10, 20 comprises an upper rotary cutting blade 112, 212 and a lower rotary cutting blade 114, 214, which may be better recognized in the following drawings. The upper rotary cutting blade 112, 212 is an example of an active cutting blade and the lower rotary cutting blade 114, 214 is an example of a passive cutting blade. The respective upper rotary cutting blades 112, 212 are movable cutting blades which are driven to rotate by rotation of the shaft 30, via a respective transmission group provided in the respective cutter module 10, 20. Each transmission group may have an adjustable transmission ratio. In the example, the lower rotary cutting blade 114, 214 may be in contact with the upper rotary cutting blade 112, 212 to be friction-driven by the upper rotary cutting blade and to cut a print medium there between. In another example, instead of providing a lower rotary cutting blade, a lower stationery blade may be provided, such as a knife like linear blade, which interacts with the upper rotary cutting blade 112, 212 to cut a print medium there between. The lower stationery blade is another example of a passive cutting blade. In another example, the upper rotary cutting blade 112, 212 may interact with a counter surface, instead of a lower cutting blade, to cut the print medium transported across the counter surface.
In the examples, each of the cutter modules 10, 20 comprises a gap 116, 216 to guide a print medium there between and towards the associated cutting blades 112, 114, 212, 214.
In the illustrated example, the lower rotary blade 114, 214 is supported by an associated rotary shaft 128, 228 supported in the lower module half 106, 206. The lower rotary blade 114, 214 may be driven by the upper rotary blade 112, 212 by friction contact between the two blades 112, 114; 212, 214. Rotary shafts 126, 128; 226, 228 as well as respective shafts of the first and second gears 120, 122; 220, 222 may be supported in the upper and lower module halves 104, 106; 204, 206 in respective bearings, not separately described.
The gear train 118, 218 is designed to rotate in one direction and to block rotation in the other direction. In the example shown, based on the perspective view of
As the arm 62, 72 is engaged with the pulley drive 12, 22, the positioner 58, 68 can be moved in the scanning direction or X direction to drag the associated cutter module 10 or 20, if engaged with the positioner 58, 68, along the shaft 30. The left hand positioner 58 can be moved across a distance spanned by the left-hand pulley drive 12, and the right and positioner 68 can be moved across a distance spanned by the right-hand pulley drive 22.
The engaging and disengaging positions of the cutter modules refer to positions in which the cutter modules are respectively lowered and raised. In the engaging position, the cutter modules generally are in a position where they would be able to perform a cutting position. Accordingly, moving the cutter module to the disengaging position comprises an upwards movement and moving the cutter module to an engaging position comprises a downwards movement. In the examples illustrated, a cutter module is engaged with the associated positioner if part of the cutter module is inserted into and held by the respective mount of the positioner. In an engaged position, a cutter module is aligned with its respective positioner and lowered so that it is inserted into the respective mount. Accordingly, an engaging position not necessarily is a position in which the cutter module and its associated positioner are engaged.
The positioner 58 of the left hand cutter module 10 is engaged with the pulley belt 14 via its arm 62, and the positioner 68 of the right hand cutter module 20 is engaged with the pulley belt 24 via its arm 72. The cutter modules 10, 20 and the positioners 58, 68 are engaged so that the positioners 58, 68 can drag the cutter modules 10, 20 in the scanning direction X, bidirectionally, along the shaft 30 to position the cutter modules at desired cutting positions.
The retractable ribs 52 are support elements to support a print medium, wherein the retractable ribs 52 cooperate to support the printable medium and are independently movable between respective protruding and retracted positions by individually engaging protruding portions of the retractable ribs by the inclined surfaces 66-1, 66-2, 76-1 of the second engaging element 66, 76 of the respective positioners 58, 68. The retractable ribs 52 may comprise elastic elements to bias the ribs 52 towards the protruding position. The print medium may be supported by the retractable ribs 52 while being cut by cutter modules 10, 20 and while being printed on.
The retractable ribs 52 of the print medium support may provide continuous guidance for the print medium through the printer. However, the retractable ribs may also obstruct the movement of the cutter modules 10, 20, which are movable in a direction perpendicular to the media advance direction, i.e. along the shaft 30, to adjust the width of the plot. To be able to move the cutter modules 10, 20, using the positioners 58, 68, and thereby adjust the width of the plot of the print medium, the inclined surfaces 66-1, 66-2, 76-1 of the positioners 58, 68 may engage with protruding portions of the ribs 52 and thereby push down and move the retractable ribs to the retracted position. When in the ribs 52 are in the retracted position, the positioners 58, 68 can move over the ribs 52. If a respective cutter module 10, 20 is engaged with its positioner 58, 68, it will be able to move over the ribs 52, together with the positioner.
In the examples shown in
For calibrating the positions of the cutter modules, the respective positioners and cutter modules can go through a homing process. At the beginning of the homing process, the system may not know the absolute and relative positions of the cutter modules 10, 20 and the positioners 58, 68, and it also may not know whether the cutter modules are engaged with the positioners or not.
The homing process is used to find the cutter modules 10, 20 at their current position along the shaft 30 and to move the cutter modules to a homing position or zero position to have a defined reference point for positioning the cutter modules at desired cutting position. This helps achieving good accuracy in positioning the cutter modules. The homing process may be run automatically after a printer is turned on, after a printer reset, after a replacement or other manipulation of a cutter module, at defined time intervals and/or after a printer cover has been opened and closed, for example. Opening and closing of a printer cover may be an indication that a user has moved or has removed and replaced a cutter module. In such a situation, the printer does not know whether the cutter modules have been moved from their previous position or even replaced. The printer also does not know whether the cutter modules are engaged or aligned with the positioners or not. The homing process may detect such external changes to the printer.
Whereas it would be possible to provide the printer with sensors for detecting that a cutter module is engaged with its associated positioner and/or for detecting the position of the cutter module along the length of the shaft, because the positioners and the cutter modules are movable along the length of the shaft, this would require sensors and flexible cabling of sensors which may be undesirable. The homing process according to the examples described herein can ensure that the cutter module is aligned and/or engaged with its associated positioner and that the position of the cutter module is known, without or essentially without the use of sensors.
The example of the homing process shown in
In the example of a homing process shown in
The positioner associated with the cutter module then can be moved away from the homing position, in examples shown in
At 1006, the printer may detect that an obstacle has been hit because, in this situation, the positioner cannot continue its movement and a torque of the drive system, such as the drive motor 40 will increase. By monitoring the motor voltage, motor current or motor torque, for example, an increase in the motor torque can be detected and used as a feedback signal indicating that the cutter module, which is dragged by its associated positioner, has hit an obstacle and hence has come to a stop. In this situation, the printer knows that the cutter module is not engaged with the positioner, because the retractable rib 52 would not be an obstacle to the positioner, as explained above. The printer further knows the relative position of the cutter module and its associated positioner because the cutter module will rest against the outer face of the mount 64 while being dragged by the positioner 58.
If the positioner travels over the entire length of the shaft 30 without hitting an obstacle, this may be an indication that a cutter module is missing. A respective message can be signaled to a user, such as on a display (not shown) of the printer.
In some examples, the cutter modules are supported on the shaft by low friction transmission rings 102, 202 so that the positioners can drag the cutter modules along the shaft 30 without or without noticeable resistance. Accordingly, when the positioner contacts and moves the cutter module, there may be no noticeable increase of torque so that this scenario cannot be detected by a respective feedback signal from the drive motor. However, if an obstacle is hit, a noticeable increase in torque of the drive motor 40 will be generated. Accordingly, the homing process can use different types of obstacles in the path of the cutter modules as reference points for detecting that the positioner has made contact with its associated cutter module.
Once the relative position of the cutter module and its associated positioner are known, the cutter module can be aligned with the positioner, at 1008, e.g. by inserting part of the lower module half into the mount 64. The funnel shape of the mount 64 allows compensating for tolerances of different cutter modules or slight offsets. The inclined interior sides of the mount 64 guide the cutter module to be centered in the mount. In a variant, engaging and disengaging the positioner 68 and the cutter module 20 can be repeated a few times, such as 3 times, to ensure that the cutter module 20 is reliably engaged with the positioner 68. Accordingly, the system now knows that the cutter module is aligned with its associated positioner and the cutter module can be engaged with the positioner to move the cutter module to a homing position, reference position or a cutting position. The cutter module also can remain at the now known position until needed for a subsequent cutting operation.
A more detailed example of a homing process is described with reference to
The homing process may begin at 1102 with placing a cutter module 20 in a disengaging position, such as shown in
At 1108, the positioner 68 is moved away from the homing position by a defined distance which, in this example, is a movement along the horizontal scanning direction to the left. If, in this situation, the cutter module 20 is engaged with the positioner 68, it will follow the movement of the positioner 68. At 1110, the cutter module is moved upwards to its disengaging position; and at 1112, the positioner is moved back, to the right, towards its homing position. This sequence of steps results in a defined relative position of the cutter module 20 and the positioner 68 in which the cutter module 20 is not engaged and not aligned with the positioner 68 but is located at least the defined distance away from the homing position and to the left of the positioner 68.
This scenario corresponds to the initial situation of the homing process described in the example of
The sequence of
At 1302, the positioner 68 and the aligned cutter module 20 are engaged by a downwards movement of the cutter module. The funnel shape of the mount 64 allows compensating for tolerances of different cutter modules or slight offsets. The inclined interior sides of the mount 64 guide the cutter module to be centered in the mount. In a variant, engaging and disengaging the positioner 68 and the cutter module 20 can be repeated a few times, such as 3 times, to ensure that the cutter module 20 is reliably engaged with the positioner 68. At this point, the position of the positioner 68 and engaged cutter module 20 is known but the positioner is not localized with high precision. The reason is that, when the cutter module hits the obstacle, due to a small deformation or variation between obstacles, the position may be known to be at the obstacle but with a tolerance of a few millimeters, such as +/−3 mm, for example.
Accordingly, at 1304, the positioner 68 and the engaged cutter module 20 are moved towards the homing position up to a defined approach position, in the drawings from left to right, at a first speed. The approach position may be defined as a position having a defined small distance to the homing position, such as a distance of about 1 cm away from the homing position. The distance may be sufficient to accommodate the positioning tolerance, addressed above. The approach position may be reached by the positioner with low precision, controlling the drive motor to drive the pulley drive and hence move the positioner across a defined distance from the previously known position at the obstacle to the defined approach position. At 1306 it is determined whether the positioner has reached the approach position. As long as the positioner has not reached the approach position, movement towards the homing position continues, at 1304.
The movement towards the approach position at the first speed may be a movement across a substantial distance along the length of the shaft 30. Therefore, selecting a higher speed may decrease the overall time of the homing procedure. However, if the positioner would not stop at the approach position but continue up to the homing position at this high speed, a relatively high deceleration may lengthen the elastic pulley belt and introduce some further inaccuracy in the positioning of the cutter module. Moreover, this could increase wear of the components of the cutter arrangement involved in the movement. Therefore, in the approach phase, the positioner is moved close to the homing position but is stopped at a distance from the homing position sufficiently large to cover the positioning tolerance. A.
At 1308, the positioner 68 and the engaged cutter module 20 are moved further towards the homing position, at a second lower speed, and it is monitored whether the positioner has reached the homing position, at 1310. As long as the positioner has not reached the homing position, movement towards the homing position continues. The fact that the positioner has reached the homing position may be detected via an increase of torque of the drive motor because the homing position may be defined by an end stop which the positioner moves against. An increase of torque, motor current or motor voltage of the drive motor, for example, may be used as a feedback signal to indicate that the homing position has been reached. The second speed may be lower than the first speed so that the low-speed movement of the positioner towards the homing position, at 1308, introduces no or no substantial bias in the transport system and increases positioning accuracy. Positioning the positioner at the second speed achieves good position accuracy and avoids high speed wear of the components involved. For example, the second speed may be about one tenth of the first speed.
At 1312, the positioner and the engaged cutter module 68 can be moved away from the homing position by a second defined distance to place the cutter module to a defined reference position. The second defined distance may be small, such as a few millimeters, but may be sufficient to overcome any backlash in the transmission group and to remove any bias in the pulley drive. In the reference position, and 1314, the cutter module may be moved upwards to its disengaging position to place the cutter module in a defined home position where it can rest until it is to be used for subsequent cutting process.
The procedures described above can be combined. For example, any one of the processes described with reference to
In a variant, when the positioner is moved first to the homing position, such as at 1104, the positioner can be moved repeatedly to the right and left, such as two or three times, to ensure that movement of the positioner is not blocked. Blocking of the positioner may be recognized from a feedback signal of the drive motor. If blocking of the positioner is detected, an alarm message can be output to a user, such as on a printer display.
A homing position may be defined by an end stop associated with a frame or chassis of the printer or by an end stop ring or protrusion located on the shaft, for example. The end stop or protrusion may be located in such a way that it blocks movement of the positioner. As explained above, the obstacle used during the homing position may be a retractable rib but also may be an end stop at the frame or chassis of the printer or an end stop ring or protrusion located on the shaft.
Drive of the print media advance system (not shown), the shaft 30 and pulley drives 12, 22 and of the cutter modules 10, 20 as well as other entities of the printer and an associated cutting equipment may be controlled by a controller (not shown). The controller can be a microcontroller, ASIC, or other control device, including control devices operating based on hardware or a combination of hardware and software. It can include an integrated memory or communicate with an external memory or both. The same controller or separate controllers may be provided for controlling carriage movement, media advance and the rotary actuator. Different parts of the controller may be located internally or externally to a printer or separate cutting device, in a concentrated or distributed environment.
Filing Document | Filing Date | Country | Kind |
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PCT/US2018/029280 | 4/25/2018 | WO | 00 |