Methods and apparatus to align components of adjustable sensors comprising at least first and second aligners

An apparatus having a first aligner rigidly connected to a first sensor component. The apparatus having a second aligner rigidly connected to a second sensor component. The apparatus having a gap positioned to receive media, wherein the first aligner is configured to attract the second aligner across the gap to align the first sensor component with the second sensor component.

FIELD

Examples disclosed herein are related to sensors and, more particularly, to methods and apparatus to align components of adjustable sensors.

BACKGROUND

Media processing devices use transmissive sensors to sense one or more elements of media (e.g., position indicators such as black marks, notches, or edges of media units) as the media passes through the media processing device from, for example, a media roll to a printhead. When the transmissive sensor senses a position indicator, the media processing device determines the position of the media or a media unit (e.g., label) relative to, for example, the printhead.

DETAILED DESCRIPTION

Some media processing devices (e.g., thermal transfer printers, direct thermal printers, radio frequency identification (RFID) tag encoders, etc.) receive and process different types (e.g., sizes) of media. In such devices, one or more sensors are tasked with detecting position indicators on media to enable the media processing device to, for example, detect an edge of a media unit (e.g., a label). In some instances, the sensors are movable along an axis to accommodate differently positioned indicators. For example, media A has indicators in a midpoint of a width of a media feed path (i.e., along a centerline), whereas media B has indicators off center of the media feed path (e.g., at a distance away from the centerline). As such, the sensor(s) tasked with sensing the indicators are moved from, for example, a centerline position when the media processing device is loaded with media A and away from the centerline position when the media processing device is loaded with media B.

When the sensor is moved to accommodate a change in indicator position, component(s) of the sensor may become misaligned. For example, an emitter of the sensor may become misaligned with a counterpart detector of the sensor. Such sensor components need to be properly aligned with each other to ensure that the detector receives a signal generated by the emitter, such that when an indicator passes between the emitter and detector, a change in the receipt of the signal at the detector occurs, thereby triggering an indicator detection. In such instances, maintaining precise alignment between the emitter-detector pair as the sensor is moved is critical.

One known system of keeping the sensor components aligned involves a thumb wheel accessible to a user. As the user rotates the thumb wheel, a first shaft coupled to an emitter rotates to shift the emitter across a width of a media feed path. The first shaft is connected to a gear train that translates rotation from the first shaft into rotation of a second shaft coupled to a detector. The rotation of the second shaft causes the detector to move similarly to the emitter, thereby maintaining alignment between the emitter and the detector. This system involves a complicated assembly of moving parts in frictional contact causing wear and tear, thereby reducing the lifespan and durability of the system. Another complication of the known system is that the assembly is highly complex with many moving, interrelated parts. This complexity affects yield during manufacturing and issues with field repair. The known assembly has an increased cost due to its complicated design. The known assembly contains cables that must translate within the assembly and are subject to binding and fatigue. In adjusting misalignment of the known assembly, full removal, disassembly, and reassembly are required. The known assembly being a fixed, rigid system creates a difficulty for routine maintenance and clearing media jams. The media gap in the known assembly is intentionally small to aid in better media unit tracking, however, because of small media gap, the known assembly cannot be easily disassembled for cleaning. The known assembly requires a skilled or trained operator to correctly re-assemble a sensor subsystem that has been dis-assembled for removing or cleaning jammed media.

Other known systems require a user to align the emitter and the detector manually. Due to precise alignment requirements of the emitter-detector pair, if the user fails to precisely align the emitter and detector, the signal received by the detector is compromised and will not provide accurate data. That is, this known system is vulnerable to user error.

Examples disclosed herein provide contactless alignment of sensor components that, in addition to eliminating adverse effects listed above, eliminates or at least reduces user error when moving a sensor to, for example, different positions in a media feed path. As described in detail below, examples disclosed herein include aligners rigidly connected to sensor components that, via a contactless (e.g., magnetic) attraction to one another, bring the sensor components into alignment with each other when moved. Additionally, examples disclosed herein maintain the achieved alignment without relying on a user to precisely align the sensor components.

FIG. 1depicts an example of a media processing device100including a sensor102constructed in accordance with teachings of this disclosure. The example media processing device100ofFIG. 1is a printer that generates indicia on media using either direct thermal printing technology or thermal transfer printing technology. However, examples disclosed herein may be implemented in any suitable media processing device that employs one or more print technologies to generate indicia on media and/or encode information onto the media. Further, while examples are described herein in connection with media processing devices, the sensor component alignment methods and apparatus disclosed herein are applicable to any device in which two or more components are required to be aligned.

The example media processing device100ofFIG. 1includes the sensor102, a media spindle104, a plurality of guide components (e.g., rollers that guide media and/or ribbon), a ribbon supply spindle106, a ribbon take-up spindle108, a platen assembly110, and a print mechanism112. The media spindle104is configured to hold a spool of media114that is fed to the print mechanism112and out an exit. In the illustrated example, the media processing device100can be configured for either direct thermal printing or thermal transfer printing. As such, the media114is either direct thermal media or thermal transfer media.

For thermal transfer printing, the ribbon supply spindle106is configured to hold a spool of unused ribbon. The ribbon is fed from the ribbon supply spindle106to the print mechanism112, which uses the ribbon to generate indicia on the media114that is concurrently fed to the print mechanism112. The ribbon take-up spindle108is configured to hold a spool of used ribbon (e.g., ribbon that has been fed through the print mechanism112).

For direct thermal printing, the media114is fed to the print mechanism112, which heats the media114to generate indicia by causing heat-sensitive dye in the media114to change color (e.g., white to black).

The example media processing device100ofFIG. 1receives data representative of printing tasks (e.g., print jobs) from internal memory and/or an external data source (e.g., a host device, a host system, a network device, and/or a removable storage device). The media processing device100processes the received data such that the data is usable to print indicia on the media114. For example, a processor of the media processing device100utilizes a print engine to generate print data lines (e.g. directly or based on a bit map image) based on the received data and transmits the print data lines (or any other type of data usable to print indicia on media) to a logic circuit of a printhead116carried by the print mechanism112. The printhead116is configured to generate indicia on the media114in accordance with the received data. For example, the logic circuit of the printhead116selectively energizes (e.g., heats) elements (e.g., printhead dots) of the printhead116according to the received data (e.g., print lines), thereby generating the corresponding indicia on the media114being fed to the printhead116. In particular, the printhead116generates indicia on the media114at a nip formed by a roller of the platen assembly110and the printhead116.

Notably, the printhead116is carefully positioned to ensure that indicia are generated in the correct location on, for example, a media unit (e.g., a label) of the media114. As such, the position of one or more aspects of the media unit relative to the printhead116is an important data point. To determine this relative position information, the media processing device utilizes the sensor102.

The example sensor102is positioned along a media feed path (i.e., the path that the media114travels from the media spindle104to the printhead116. The media processing device100utilizes indicators on the media114to determine the position of the media114and/or a particular media unit (e.g., label) relative to, for example, the printhead116. The example sensor102is tasked with detecting such indicators. A challenge arises when the media processing device100is capable of processing different types (e.g., sizes) of media for which the indicators may be positioned at different locations on the media web. In particular, to accommodate the differently positioned indicators, the sensor102is movable across the media feed path. As described above, movement of the sensor102introduces a risk of misalignment between components of the sensor102. However, as detailed below, the example sensor102achieves and maintains alignment of the components thereof.

FIG. 2depicts an embodiment of the example sensor102ofFIG. 1in isolation from other elements of the media processing device100. The example sensor102has a first housing200and a second housing202. In this example, the first housing200and the second housing202are separated by gap204through which the media114passes. The example first housing200ofFIG. 2contains a first carrier300(FIG. 3) configured to travel within the first housing200in a direction along a longitudinal axis206. The example second housing202ofFIG. 2contains a second carrier302(FIG. 3) configured to travel within the second housing202in a direction along the longitudinal axis206. In the illustrated example, the first carrier300has a tab210protruding through a slot208. The tab210is configured to provide a user with a gripping surface such that the user can move the first carrier300within the first housing200by sliding the tab210along the longitudinal axis206. The slot208extends the length of the first housing200to allow the tab210to move the first carrier300from one end of the housing200to the other.

FIG. 3is a cross section of the view shown inFIG. 2along axis A-A. As shown inFIG. 3, the first carrier300holds a first sensor component304and a first aligner308. The first carrier300supports the first sensor component304and the first aligner308in a fixed relationship to each other such that the first carrier300maintains a distance and an orientation between the first sensor component304and the first aligner308. In the example ofFIG. 3, the distance is between a center of the first aligner308and a center of the first sensor component304. However, alternative reference points are possible. In the illustrated example, the first sensor component304is an emitted configured to emit a signal (e.g., a light pulse, sound pulse, magnetic pulse, electric pulse). The first sensor component304is positioned within the first carrier300such that the first sensor component304directs the signal through a first aperture316in the first carrier300. In another embodiment, the first sensor component304is in the second housing202and directs the signal to the second sensor component306located in the first housing200.

Similarly, in the illustrated example, the second carrier302holds a second sensor component306and a second aligner310. In the illustrated embodiment, the second carrier302supports the second sensor component306and the second aligner310in a fixed relationship to each other such that the second carrier302maintains distance between the second sensor component306and the second aligner310. In the illustrated example, the second sensor component306is a detector configured to receive a signal (e.g., a photovoltaic cell, a microphone, a hall sensor). The second sensor component306is positioned within the second carrier302such that the second sensor component306directs the signal through a second aperture318in the second carrier302.

In the illustrated example, when the first aligner308is aligned with the second aligner310(i.e., the respective centers are along a common axis), the first aperture316of the first carrier300is aligned with the second aperture318of the second carrier302. In the illustrated example, the aligned first aligner308and second aligner310allow signals emitted from the first sensor component304to be received by the second sensor component306. Through this process, signals read by the second sensor component306can be detected via a processor.

In the illustrated embodiment, the first aligner308and the second aligner310are magnetically attracted to each other such that the second carrier302is held aloft within the second housing202such that a second gap324exists between the second carrier302and a surface of the second housing202. The second gap324will be discussed in detail below.

In some examples, the first carrier300has a LED (not shown) that indicates the position of the first sensor component304within the first housing200. The LED provides a light mark that can be seen within the gap204, which enables the user to see where the first sensor component304is located. This is helpful for the user when the user is moving the first sensor component304via the tab210.

In the illustrated embodiment, the first sensor component304moves in conjunction with (e.g., simultaneously and in the same direction as) the first aligner304within the first housing200. In the illustrated example, the first aligner304is a magnet having a first polarity.

In the illustrated embodiment, a magnet having a second polarity opposite the first polarity of the first aligner304. In the illustrated embodiment, the first polarity of the first aligner304is attracted to the second polarity of the second aligner306.

In the illustrated embodiment, the first housing200has a first printed circuit board (PCB)312. The first PCB312provides power and data communication to the first sensor component304. In the illustrated embodiment, the second housing202has a second PCB314. The second PCB314provides power and data communication to the second sensor component306. In the illustrated embodiment, as will be described in further detail below, both the first PCB312and the second PCB314are in communication with the processor via a respective first electrical connector320and a second electrical connector322, respectively.

In the illustrated embodiment, the first sensor component304and the second sensor component306may be photovoltaic sensors, hall sensors, LED sensors, proximity sensors, light-based sensors, or any other type of equivalent sensor.

FIG. 4shows a cross sectional view of the first sensor102. In the illustrated embodiment, the first carrier300has a biasing device404positioned between the first carrier300and an inner wall of the first housing200. In the illustrated embodiment, the biasing device404is a leaf spring. The biasing device404can be any device capable of providing a force to between the first carrier300and the inner wall of the first housing200. The example biasing device404ofFIG. 4provides a force against the first carrier300such that the first carrier300is pressed into a housing wall opposite the inner wall such that frictional forces are created to keep the first carrier300in one position throughout normal media processing operations. In the illustrated embodiment, the biasing device404acts against the first carrier300to hold the first carrier300in place during normal activity of the media processing unit100. The media processing unit100may gently vibrate or the sensor102may vibrate due to the media passing by which can cause the first carrier300to come unaligned over time. The biasing device404maintains alignment. However, a user can still overcome the force applied by the biasing device404to move the first carrier300to a different position when necessary. That is, the force applied by the biasing device404is great enough to prevent undesirable movement due to, for example, vibrations, but not strong enough to prevent a user from moving the first carrier300using the tab210.

In the illustrated embodiment, the first PCB312and the second PCB314are designed with a space in the middle that allows the first carrier300to extend through the space in the first PCB312and for the second carrier302to extend through the space in the second PCB314. In the illustrated embodiment, the first carrier300has a first carrier PCB406secured within the first carrier300in communication with the first sensor component304. In the illustrated embodiment, the second carrier302has a second carrier PCB408secured within the second carrier302in communication with the second sensor component306. The carrier PCBs406and408are connected to their associated components within the same carrier300and302, respectively. The first PCB406is connected to the first sensor component304and the first contacts400. The second PCB408is connected to the second sensor component306and the second contacts402. In the illustrated embodiment, a pivoting screw410is shown extending through the first housing200and the second housing202. The pivoting screw410will be explained in further detail below.

In the illustrated embodiment, the first carrier PCB406is in communication with the first PCB312via first contacts400. In the illustrated embodiment, the second carrier PCB408is in communication with the second PCB314via second contacts402. In the illustrated embodiment, the first contacts400and the second contacts402are electrical contacts that enable communication between the first carrier PCB406and the first PCB312, and between the second carrier PCB408with the second PCB314, respectively. In the illustrated embodiment, the first carrier300is supported by the first PCB312such that when the first carrier300moves within the first housing200, the first contacts400maintain a connectivity to the first PCB312.

In the illustrated embodiment, the second carrier302is supported via the attraction between the first aligner308and the second aligner310such that when the second carrier302is in a supported position, the second gap324exists between the second carrier302and the second housing202. In the illustrated embodiment, a supported position is achieved when the first aligner308and the second aligner310are aligned and the attraction between the aligners308and310causes the second carrier302to be held aloft. When the second carrier302is in the supported position, the second contacts402are in contact with the second PCB314.

When the first aligner308and the second aligner310become unaligned, the second aligner310loses the attraction to the first aligner308and can no longer hold the second carrier302aloft within the second housing202. When this happens, the second carrier302is unsupported and falls within the second housing202the distance of the second gap324to rest on the surface of the second carrier302. When the second carrier302falls within the second housing202, the second carrier302falls away from the first carrier300along a center axis412. The second carrier302falling the distance of the second gap324causes the second contacts402to lose connection to the second PCB314. When the second contacts402lose connection to the second PCB314, the second sensor component306no longer communicates with the processor. The processor then recognizes that the second sensor component306is no longer in communication and the processor may generate an alert. The generated alert may be a sound, a text alert, an alarm, a noise, a light, or a notice on a user interface.

FIG. 5depicts another embodiment where the first carrier300contains a third aligner500and the second carrier302contains a fourth aligner502. In the illustrated embodiment ofFIG. 5, the third aligner500is fixedly positioned adjacent to the first sensor component304such that the first sensor component304is between the first aligner308and the third aligner500. In the illustrated embodiment ofFIG. 5, the fourth aligner502is fixedly positioned adjacent to the second sensor component306such that the second sensor component306is between the second aligner310and the fourth aligner502. In the illustrated embodiment, the third aligner500has a third polarity and the fourth aligner502has a fourth polarity where the third polarity and the fourth polarity are different and therefore attract each other. In the illustrated embodiment, the third polarity and the second polarity are the same and the first polarity and the fourth polarity are the same. In the illustrated embodiment, the different polarities cause the unaligned aligners (e.g. the first aligner308/fourth aligner502and the second aligner310/third aligner500) to repel each other. In the illustrated embodiment, the aligner arrangement maintains an alignment of the first sensor component304and the second sensor component306as the first carrier300is moved and the second carrier302moves correspondingly. Similar to the example ofFIG. 4, misalignment of the sensor components304and306causes the second carrier302to no longer be pulled toward the first carrier300causing the second carrier to drop and lose the connection between the PCBs.

FIG. 6depicts the sensor102with media600passing through the gap204. The media600follows the media feed path through the sensor102during operation of the media processing device100. In the illustrated embodiment, the media600comprises a media web602on which media units604are arranged. In the illustrated embodiment, the media units604have an indicator (not shown) which is detectable by the sensor102. The indicator will be discussed in greater detail below. In the illustrated embodiment, as the media units604pass through the gap204, the indicator on each media unit604(or elsewhere on the web602) is sensed by the passing of signal between the first sensor component304and the second sensor component306. In the illustrated embodiment, the media units604are labels on a media web602, however in other embodiments the media units604may be any medium capable of being processed within a media processing device including but not limited to cards, thermal transfer labels, direct thermal labels, laminated labels, or liner-less labels.

FIG. 7depicts an under side of the media600as shown inFIG. 6. In the illustrated embodiment, the media web602has a first media unit700and a second media unit702. The first media unit700has a first indicator704. And the second media unit702has a second indicator706. In the illustrated embodiment, the first indicator704and the second indicator706are black marks. In other embodiments, the first indicator704and the second indicator706may be a mark, a gap in the media, an object embedded in the media unit, a leading edge of the media unit, a trailing edge of the media unit, or anything that could indicate the position of the media unit with relation to, for example, the printhead116. In the illustrated embodiment, the first indicator704and the second indicator706are not positioned at the same point along a width of the media web602, where the width of the media web is the dimension that is perpendicular to the feed direction and parallel to the printhead116. If the sensor102was set up to detect indicators that are positioned similarly to the first indicator704, then the sensor would fail to detect the second indicator706as the second indicator706is not positioned the same as the first indicator704. The sensor102would have to be realigned to detect the second indicator706.

Referring toFIG. 2, the user would reposition the first carrier300(and, thus, the sensor component thereof) via the use of the tab210. As the first carrier300moved, the first sensor component304and the first aligner308would move correspondingly with the first carrier300. As the first aligner308moved, the second aligner310would move correspondingly because of the magnetic attraction between the first aligner308and the second aligner310. Therefore, as the first carrier300slides along the axis206within the first housing200, the second carrier302would slide correspondingly within the second housing202. In the illustrated embodiment, as the first aligner308moved with the second aligner310, the first sensor component304and the second sensor component306would also move correspondingly with each other due to their fixed spatial relationships with the corresponding aligners. In the illustrated embodiment, the first carrier300would be moved until the first sensor component304aligned with the second indicator706. This would allow the sensor102to adapt to the change of position of the indicator on the media and to continue to function as needed.

FIG. 8is a cross section ofFIG. 6along the line C-C. In the illustrated embodiment, the first sensor component304emits signal through the first aperture316, through the media600, through the second aperture318, and then received by the second sensor component306. In the illustrated embodiment, the first aperture316and the second aperture318act to prevent ambient light from interfering with the second sensor component306. In other embodiments, the first aperture316and the second aperture318can be various sizes based on electrical functionality required by the system. In the illustrated embodiment, the second sensor component306senses a percentage of the light signal emitted by the first sensor component304and the amount of light sensed is relevant to detecting indicators. In the illustrated embodiment, if there was ambient light reaching the second sensor component306, then the reading would be inaccurate. In the illustrated embodiment, if the first aligner308and the second aligner310were to become unaligned, this would cause the first sensor component304and the second sensor component306to become unaligned and prevent the detecting indicators.

FIG. 9depicts an example of the sensor102showing the first electrical connector320and the second electrical connector322. In this example, the first electrical connector320and the second electrical connector322are arranged behind a physical firewall (not shown) and positioned to allow the first PCB312and the second PCB314to be plugged into the first electrical connector320and the second electrical connector322, respectively. In the illustrated embodiment, the first PCB312and the second PCB314connect to the processor of the media processing device100via the connection to the first electrical connector320and the second electrical connector322, respectively. In this example, the first electrical connector320and the second electrical connector322allow for the sensor102to be plugged into the electrical connectors and removed from the connectors without undue difficulty. In this example, the sensor102is modular as it can be easily removed and installed as a separate part to the media processing device100, which helps in cleaning the sensor102.

How to Recouple when the Aligners Become Unaligned

In the illustrated embodiment inFIG. 3, when the first aligner308and the second aligner310are unaligned, the second carrier302will fall into the gap324as described above, which is sensed by the processor via the loss of connection between the second contacts402and the second PCB314. In response, the user must realign the sensor components. In the illustrated embodiment, when the first carrier300and the second carrier302are misaligned, the user moves the first carrier300within the first housing200towards the second carrier302. As the first aligner308approaches the second aligner310, the polarity difference between the first aligner308and the second aligner310causes the second aligner310to be attracted to the first aligner308. As the second aligner310approaches the first aligner308, the second aligner310is attracted to the first aligner308and the second carrier302is lifted within the second housing202and back into contact with the second PCB314, as described above.

This process is different for the embodiment shown inFIG. 5. In the illustrated embodiment ofFIG. 5, the first aligner308and the second aligner310are aligned, and the third aligner500and the fourth aligner502are also aligned. In the embodiment ofFIG. 5, when the first carrier300and the second carrier302are unaligned and the second carrier302drops within the second housing202as described above, the process to realign the carriers is slightly different than the example ofFIG. 3. In the embodiment ofFIG. 5, when the user moves the first aligner308towards the second aligner310, the first aligner308may first come near the fourth aligner502, and as stated above, the first aligner308and the fourth aligner502have the same polarity. This causes the first aligner308to repel the fourth aligner502which would result in the second carrier302to move away from the first carrier300as the user moves the first carrier300towards the second carrier302. As such, the user continues to “push” the second carrier302with the first carrier300until the second carrier302comes into contact with a side wall of the second housing202. In the illustrated embodiment, once the second carrier302is against the wall and unable to move, the user will be able to overcome the repelling of the first aligner308by the fourth aligner502and force the first aligner308back into alignment with the second aligner310. In the illustrated embodiment, once the first aligner308and the second aligner310are realigned, the attraction between the aligners will cause the realignment of the first sensor component304with the second sensor component306.

Accessibility when Cleaning

Some transmissive sensors experience a residue build-up within the gap over time. This residue may be glue, laminate, or any other substance that can be rubbed off from media. An example embodiment ofFIG. 10addresses this issue.

FIG. 10depicts an example sensor102where the first housing200and the second housing202are shown separated to show the pivoting screw410and a pivoting nut1000. The pivoting screw410and the pivoting nut1000can be any type of connecting means which can be connected and unconnected. In the illustrated embodiment, the pivoting screw410extends from the first housing200towards the second housing202. The example embodiment allows the sensor102to be easily assembled by passing the pivoting screw410through an opening in the second housing202and securing the sensor102together with the pivoting nut1000. When the first housing200and the second housing202as depicted in embodiment ofFIG. 10are separated, the residue build-up can be accessed and removed. Built-up residue between the first housing200and the second housing202may deter operation of the media processing device100by preventing media from passing through the example sensor102cleanly.

FIG. 11depicts the first housing200and the second housing202pivoting relative to each other. In the illustrated embodiment, the pivoting of the first housing200and the second housing202exposes a first face1100of the first housing200and a second face1102of the second housing202that are on either side of the gap204. In the example embodiment, the faces1100and1102of the first housing200and the second housing202are able to be cleaned.