阅读说明：本技术 打印材料料位感测 (Printing material level sensing ) 是由 E·C·达格 D·E·安德森 J·M·加德纳 于 2019-04-05 设计创作，主要内容包括：一种打印材料料位传感器,包括一系列打印材料料位感测设备,该系列打印材料料位感测设备间隔设置以检测容器中的连续深度区域处的打印材料的存在,其中每个打印材料料位感测设备包括用于在其深度区域处发射热量的加热器和用于感测深度区域处的热量并基于所感测的热量输出信号的传感器。传感器具有控制电路,对于待校准的每个打印材料料位感测设备,该控制电路用于在由初始热量计数设置的初始持续时间内开启加热器,并且根据经调节的热量计数迭代地调节加热器被开启的持续时间,直到来自传感器的信号输出指示在这个深度区域中已经达到目标值。(A printing material level sensor comprising a series of printing material level sensing devices spaced apart to detect the presence of printing material at successive depth zones in a container, wherein each printing material level sensing device comprises a heater for emitting heat at its depth zone and a sensor for sensing heat at the depth zone and outputting a signal based on the sensed heat. The sensor has a control circuit for, for each printing material level sensing device to be calibrated, turning on the heater for an initial duration set by an initial heat count, and iteratively adjusting the duration for which the heater is turned on in accordance with the adjusted heat count until a signal output from the sensor indicates that a target value has been reached in this depth region.)

1. A printing material level sensor comprising:

a set of spaced apart printing material level sensing devices for detecting the presence of printing material at successive depth zones in the container, wherein each printing material level sensing device comprises a heater for emitting heat at its depth zone and a sensor for sensing heat at the depth zone and outputting a signal based on the sensed heat; and

a control circuit for turning on the heater for an initial duration set by an initial heat count for each printing material level sensing device to be calibrated, and iteratively adjusting the duration for which the heater is turned on in accordance with the adjusted heat count until a signal output by the sensor indicates that a target value has been reached in that depth region.

2. The printing material level sensor of claim 1, the control circuit having a heat pulse generator for receiving the initial heat count and outputting a heat pulse to turn on the heater for the initial duration according to the initial heat count.

3. The printing material level sensor of claim 2, the heat pulse generator to receive an adjusted heat count and output a heat pulse to turn on the heater for an adjusted duration in accordance with the adjusted heat count.

4. A printing material level sensor according to claim 2 or 3, said control circuit having a register for holding said initial heat count to be input to said heat pulse generator.

5. The printing material level sensor of claim 4, wherein the register receives an adjusted heat count to be input to the heat pulse generator.

6. The printing material level sensor of any preceding claim, wherein the control circuitry first calibrates printing material level sensing devices at depth regions closer to a power supply node, and then subsequently calibrates printing material level sensing devices at depth regions further from the power supply node.

7. A printing material level sensor according to any of the preceding claims, wherein said register saves an adjusted heat count for a previously calibrated printing material level sensing device reaching said target value as said initial heat count for a next printing material level sensing device to be calibrated.

8. The printing material level sensor of any of the preceding claims, wherein the heat count has at least one of a minimum heat count value and a maximum heat count value, wherein the heat count cannot be reduced below the minimum heat count value and the heat count cannot be increased beyond the maximum heat count value.

9. The printing material level sensor of any of the preceding claims, wherein the control circuitry comprises at least one of a counter for incrementing the heat count and a counter for decrementing the heat count.

10. A printing material level sensor according to any of the preceding claims, wherein the control circuit comprises a comparator for comparing a value of a signal output by the sensor with the target value.

11. The printing material level sensor of any of the preceding claims, wherein the printing material level sensing device set is provided on an elongated strip having an aspect ratio of at least 20.

12. A printing material container comprising:

a chamber for holding a volume of printing material;

a set of spaced apart printing material level sensing devices for detecting the presence of the printing material at successive depth zones in the chamber, wherein each printing material level sensing device comprises a heater for emitting heat at its depth zone and a sensor for sensing the heat at the depth zone and outputting a signal based on the sensed heat; and

a control circuit for turning on the heater for an initial duration set by an initial heat count for each printing material level sensing device to be calibrated, and iteratively adjusting the duration for which the heater is turned on in accordance with the adjusted heat count until a signal output from the sensor indicates that a target value has been reached in that depth region.

13. A method, comprising:

calibrating a marking material level sensing device disposed at a continuous depth region in a container holding a volume of marking material; wherein the calibration comprises, for each marking material level sensing device to be calibrated,

turning on a heater of the printing material level sensing device for an initial duration to emit heat at a depth region of the printing material level sensing device;

sensing heat received by a thermal sensor at a depth region of the printing material level sensing device; and iteratively adjusting a duration for which the heater is turned on until the signal output by the thermal sensor indicates that a target value has been reached at the depth zone.

14. The method of claim 13, wherein the printing material level sensing devices are sequentially calibrated in order of depth regions from depth regions closer to a power supply node to depth regions further from the power supply node.

15. The method of claim 13 or 14, wherein each of the printing material level sensing devices is submerged below an upper surface of printing material in the container.

Background

The printing apparatus ejects a printing material to form an image or structure.

The printing material may be stored in a container from which it is taken out by the printing apparatus for ejection. Over time, the level of marking material in the container decreases. A printing material level sensor is useful for determining a current level of printing material.

Drawings

Examples will now be described, by way of non-limiting example, with reference to the accompanying drawings, in which:

FIG. 1 illustrates an example print material level sensor;

FIG. 2 shows an example printing material level sensing device set;

FIG. 3 shows measurement results of ink level sensing;

FIGS. 4A and 4B illustrate example signal attenuations after heating has ceased;

FIG. 5 illustrates an example control circuit;

FIG. 6 illustrates an example control circuit;

FIG. 7 illustrates an example control circuit;

FIG. 8 illustrates an example control circuit;

FIG. 9 illustrates an example calibration process;

FIG. 10 illustrates an example calibration process;

FIG. 11 illustrates example print material level sensing;

FIG. 12A illustrates an example printing material container;

FIG. 12B shows an example print material level sensor and example electrical connection contacts;

fig. 13A to 13C show an example series of printing material level sensing devices.

Detailed Description

Fig. 1 shows an example printing material level sensor 1. The example printing material level sensor 1 comprises a set of printing material level sensing devices 2 and control circuitry 3. The series of printing material level sensing devices 2 receives electrical power from the node 10. The node 10 receives electrical power from a power source.

Fig. 2 shows an example of a part of a set of printing material level sensing devices 2. In the example of fig. 2, a pair of heater 4 and sensor 5 forms a printing material level sensing device 6. In this way, the groups of printing material level sensing devices are spaced apart to detect the presence of printing material at successive depth regions within the volume 7. The volume 7 is shown partially filled with printing material 8. The remainder of the volume may be filled with a gas, such as air 9. As the printing material is used by the printing device for printing, the degree to which the volume is filled by the printing material will vary over time. If the printing material in the volume is replenished, the degree to which the volume is filled will also change. Example printing materials may include any of inks (e.g., dye-based inks or pigment-based inks), fixatives (e.g., for tie inks), primers (e.g., for undercoats), topcoats (e.g., for coatings), fluxing agents (e.g., for three-dimensional printing), and fine agents (e.g., for three-dimensional printing). Moreover, suitable printing materials may, for example, include materials that can be titrated for life science applications.

The heater 4 of the printing material level sensing device 6 emits heat at a depth region thereof, and the sensor 5 senses the heat at the depth region to output a signal based on the sensed heat. The sensor 5 is close enough to the heater 4 to sense heat when the heater is emitting heat. The wiring 11 enables supply of electric power from the node 10 to the heaters 4 in the group 2. The wiring 11 may be in the form of, for example, metal traces, such as thin film metal traces, that transmit power from a power source to the heater. The metal traces may be formed on the carrier by a silicon complementary CMOS fabrication process. The metal traces may, for example, comprise aluminum. As an example, the metal traces can have a width of no greater than 100 μm and a length of at least 10000 μm.

The control circuit 3 enables calibration of the printing material level sensing device to be performed. For each printing material level sensing device to be calibrated, the control circuitry may turn on the heater for an initial duration set by an initial heat count, and iteratively adjust the duration for which the heater is turned on in accordance with the adjusted heat count until the signal output from the sensor indicates that the target value has been reached in this depth region.

By performing calibration in this manner, for each printing material level sensing device, it is possible to determine a heat count at which the sensor output gives a desired target value. By determining the heat count, the associated duration for which the heater 4 of the printing material level sensing device 6 will be switched on during subsequent sensing is also determined. Thus, a heat count, and thus a duration of time the heater is turned on during printing material level sensing, may be determined for each individual printing material level sensing device. During a subsequent printing material level sensing by the printing material level sensor, the heater of each printing material level sensing device may then be turned on for a duration determined for that heater during calibration. In one example, the calibration is performed when the intended volume 7 is filled with printing material 8. In other words, when each of the printing material level sensing devices is expected to be submerged below the upper surface of the printing material in the container. This may be, for example, when a printing material container containing printing material and having a printing material level sensor therein is first connected to the printer device, a calibration is performed.

Fig. 3 shows measurements obtained from a printing material level sensor that has not been calibrated as described above. Fig. 3 shows the measurement results from sensor 0 to sensor 120 of the printing material level sensing device group. In contrast to the above description, the data of fig. 3 was obtained by heating each heater for the same predetermined amount of time. The sensors are labeled along the x-axis from sensor 0 at the top position to sensor 120 at the bottom position. In this arrangement, the sensor 0 and its associated heater (heater 0) are closest to the power supply that powers the heater. The sensor 120 and its associated heater (heater 120) are furthest from the power source that powers the heater. The y-axis shows the measured value of the signal output by each sensor. Measurements are obtained from the sensors by turning on their associated heaters for a predetermined amount of time, turning off the heaters, waiting for a fixed amount of delay to expire, and then measuring the signal.

In fig. 3, the upper line in the result is a case where air is present around all the sensors from sensor 0 at the top to sensor 120 at the bottom. In other words, the container is empty and no printing material is present. The lower line in the result is the situation where there is printing material (ink in this example) from the bottom sensor 120 up to around the sensor 50. Above the periphery of the sensor 50, i.e. from there to the sensor 0, there is air. The resulting step change in the lower line shows the transition from printed material to air. It thus shows the level of printing material present in the container and thus the amount of printing material.

It can also be seen from fig. 3 that the upper line of results has a slope from sensor 0 position at the left side of the graph to sensor 120 position at the right side of the graph. For sensor 0, a meter value in excess of 180 is measured, and for sensor 120, a measurement count value in excess of 100 is measured. Thus, as the sensor position becomes farther from the top and closer to the bottom, the measurement decreases.

The resulting lower line exhibits similar slopes in both the areas where air is present and the areas where printing material is present. The dashed line shows how the slope in the area where the printing material is present will continue if the printing material will be present all the way to the sensor 0 position. It can be seen that the difference in the measured values depending on which of the air and the printed material is present at the position of the sensor 0 is significantly higher than the difference in the measured values depending on which of the air and the printed material is present at the position of the sensor 120. Thus, it can be determined that the sensitivity to the presence of air and printing material is greater at the sensor 0 location than at the sensor 120 location.

The inventors have determined that the decrease in the measured value is due to the heater of the printing material level sensing device suffering from a parasitic voltage drop as the distance from the power supply increases. A narrow carrier with a set of printing material level sensing devices thereon may be provided and narrow wiring for transferring electrical power from the nodes to the printing material level sensing devices contributes to parasitic voltage drops. As a result of the parasitic voltage drop, heaters that are farther from the power supply receive less power at a given time than heaters that are closer to the node and therefore closer to the power supply. The reason for the parasitic voltage drop in the wiring is the narrowness of the wiring and the thickness to which it can be manufactured. In other words, the wiring has a width much smaller than its length. The length of the wiring, and therefore the parasitic voltage drop, is greater for heaters further from the power supply than for heaters closer to the power supply. As described above, the wiring may be in the form of metal traces, such as thin film metal traces, for example. As an example, the metal traces can have a width of no greater than 100 μm and a length of at least 10000 μm.

In contrast to the measurements shown in fig. 3, the above example calibration enables the heater of each printing material level sensing device to be powered for a duration determined for that printing material level sensing device during subsequent level sensing to obtain a target value in the signal output by the sensor of the printing material level sensing device. As an example, by using the same target value for each of the printing material level sensing devices during calibration, it may be enabled to perform subsequent measurements from the same or similar starting temperature at each of the printing material level sensing devices, irrespective of the depth region in which the printing material level sensing device is located. Accordingly, the same or similar sensitivity can be achieved for each printing material level sensing device, and an undesirable decrease in signal-to-noise ratio (SNR) can be avoided, thereby enabling more accurate determination of the remaining amount of printing material. In an example arrangement where the uppermost sensor is closest to the node and hence the power supply, and the lowermost sensor is furthest from the node, the remaining amount of printing material can be accurately determined as the container approaches an empty condition.

Fig. 4A and 4B show the effect of heating the heater at the depth zone to obtain a higher starting temperature before making a measurement. For example, if the measurement is taken after a fixed delay time has been reached since the heating was stopped, then for a higher starting temperature, a greater decay in the sensed signal may occur during the delay time. A greater degree of differentiation is provided compared to depth regions that decay from a lower onset temperature. Thus, the circuit has a greater dynamic range to operate. The rate of decay from the starting temperature will vary depending on the thermal capacity of the material present around the sensor, from which it can be determined which of the printing material and air is present.

Turning again to the examples of fig. 1 and 2, in one example, the control circuit 3 may have a heat pulse generator 12 as shown in fig. 5 to receive the initial heat count and output a heat pulse signal to turn on the heater 4 for an initial duration according to the initial heat count.

In an example, the heat pulse generator 12 may also receive the adjusted heat count and output a heat pulse signal to turn on the heater for an adjusted duration in accordance with the adjusted heat count. Thereafter, this process may be repeated for a new adjusted heat count until the value of the sensor output signal reaches the target value.

As a further example, the control circuit 3 may have a memory, such as a register 13, to hold an initial heat count to be input to the heat pulse generator 12. The register may then receive and hold the adjusted heat count to be input to the heat pulse generator. The register may receive a plurality of successively adjusted heat counts. When the register receives a new heat count, it may overwrite the previously saved heat count with the new heat count. The register may output the currently saved heat count to the heat pulse generator such that the heat pulse generator generates a heat pulse signal based on the heat count. An example of a control circuit with registers is shown in fig. 6.

In one example of a printing material level sensor, the control circuitry first calibrates the printing material level sensing devices at depth regions closer to the power supply node, and then sequentially calibrates the printing material level sensing devices at depth regions further from the power supply node. In one example, a memory (such as register 13) may, for example, save the adjusted heat count at which the target value was reached for a previously calibrated printing material level sensing device as the initial heat count for the next printing material level sensing device to be calibrated.

In one example, the heat count may have at least one of a minimum heat count value and a maximum heat count value, wherein the heat count cannot be decreased below the minimum heat count value and the heat count cannot be increased beyond the maximum heat count value. Thus, there may be a minimum duration for which the heater may be turned on and a maximum duration for which the heater may be turned on. This may enable to avoid that under heating occurs or that calibration or subsequent level sensing takes too long or damages the device.

In further examples, a controller 14, such as a microcontroller, CPU, processing unit, may adjust the heat count and provide the adjusted heat count to the register 13, as shown in fig. 7. As another example, the controller 14 may provide the adjusted heat count directly to the heat pulse generator 12. As an example, the controller may determine an adjusted heat count based on the heat count and the signal output by the sensor. For example, the controller may compare the value of the signal output by the sensor to a target value and adjust the heat count based on the difference.

In one example, the heat pulse signal generated by the heat pulse generator may control a switch to turn on a heater of the printing material level sensing device in the selected region. An example is shown in fig. 8. Here, the heat pulse signal generated by the heat pulse generator controls a switch to supply electric power to the heater 4 of the printing material level sensing device in the selected region through the wiring 11. For example, the switch may be a field-effect transistor (FET) that may be enabled by the heat pulse signal. In fig. 8, a single heater 4 and sensor 5 are depicted for simplicity. It will be appreciated that each heater 4 and sensor 5 is similarly connected to the control circuit.

FIG. 9 shows an example calibration process for a printing material level sensing apparatus. The initial duration is used to turn on a heater of the printing material level sensing device. The initial duration may be indicated, for example, by a heat count. The heat received by the sensor of the printing material level sensing device is sensed by the sensor. The signal value output by the sensor may be compared with a target value. The duration may be adjusted if the value of the output signal is not equal to the target value. The duration may be increased if the value of the output signal is below a target value. The duration may be reduced if the value of the output signal is higher than a target value. The adjustment may be an adjustment of the heat count indicating the duration. The heater is then turned on for the adjusted duration based on, for example, the adjusted heat count. This process may be repeated until the value of the signal output by the sensor equals the target value. In one example, a value of a signal output by a sensor may be considered equal to a target value if the value falls within a given range of the target value. As an example, a heat count with a signal value output by the sensor equal to a target value may be stored in the memory. For example, it may be stored in a non-volatile memory of a printing material container provided with a printing material level sensor. As an example, the non-volatile memory may be part of an ink level sensor.

FIG. 10 illustrates another example calibration process. In this example process, a printing material level sensing device to be calibrated is selected. This may be based on, for example, a region selection signal. The region selection signal may be received from an external device, such as a printer, or may be generated or otherwise obtained by the control circuit 3, for example. An initial heat count for the selected region may be set. The initial heat count may be received by the control circuit 3 from an external device, such as a printer, or may be generated or obtained by the controller 14, for example. The initial heat count may be input into a memory, such as register 13, or directly into heat pulse generator 12. The heater 4 of the selected printing material level sensing device 6 may be turned on for the duration indicated by the initial heat count. A sensor of the printing material level sensing device senses the received heat. The value of the signal output by the sensor may be compared to a target value. The heat count may be adjusted if the value of the signal output by the sensor is not equal to the target value. If the value of the signal output by the sensor falls within a given range of the target value, the value can be considered to be equal to the target value. To determine any adjustments to the heat count, it is determined whether the value output by the sensor is greater than or less than a target value. If greater than the target value, the heat count will be decremented. If less than the target value, the heat count will be incremented. The magnitude at which the heat count is decremented or incremented may depend on the magnitude of the difference between the value of the signal output by the sensor and the target value. The heater of the selected printing material level sensing device may then be turned on for the duration indicated by the adjusted heat count. This process may be repeated until the value of the signal output by the sensor equals the target value. If it is determined that the signal output by the sensor is equal to the target value, it may be determined whether to calibrate another one of the printing material level sensing devices. If another printing material level sensing device is to be calibrated, the calibration process is repeated for that device. As an example, the calibration process may be repeated until each of the printing material level sensing devices has been calibrated. For a calibrated printing material level sensing device, a heat count may be stored at which the signal value output by the sensor equals a target value. For example, the heat count may be output to memory or an external device (such as a printer) for storage. As an example, the heat count may be stored in a non-volatile memory provided to a printing material container provided with a printing material level sensor. As an example, the non-volatile memory may be part of an ink level sensor. By storing the calibration values in the non-volatile memory of the container, these values can be maintained even if the supply of electric power to the container is stopped. For example, if the container is attached to a printer and powered off. The calibration values can be maintained even if, for example, the container is taken out of the printer and connected to another printer.

FIG. 11 shows an example of print level sensing after calibration has been performed. In this example, a printing material level sensing device is selected and the heat count obtained during calibration for this printing material level sensing device is set. The measurement is then performed by heating the heater of this device and sensing with the sensor of the device. After the measurement has been performed, it is determined whether the measurement should be performed at another area. For example, it may be determined to perform measurements on another area until measurements have been performed on all areas. If a measurement is to be performed at another area, the sensor for this area is selected and the heat count determined during calibration for this area is set. Heating and sensing is then performed by the printing material level sensing means of this region. After the measurement of the region has been completed, in other words when it is determined that no other region is measured, the data obtained from the measurement can be used to determine the level of printing material present.

Fig. 12A shows an example printing material container 20 with a printing material level sensor therein. The printing material container 20 includes electrical connection contacts 21 for connection to electrical connectors of the printer. The electrical connection contacts 21 are also connected to a printing material level sensor provided in the container 20. An example of the printing material level sensor 1 and the electrical connection contacts 21 is shown in fig. 12B. In this example, four electrical connection contacts are provided, namely a ground connection contact G, a serial clock connection contact C, a supply voltage connection contact V, and a serial data input/output contact D. More or fewer contacts may be provided. The electrical connection contacts may form a communication bus protocol, e.g./for communicating with a printer²And C, a data interface. The electrical connection contacts may enable communication of signals and electrical power between the printer and the printing material level sensor.

Fig. 2 described above shows one example of a set of printing material level sensing devices. Further examples of a set of printing material level sensing devices are shown in fig. 13A to 13C. In the example of fig. 13A, the heater 4 and the sensor 5 are arranged in pairs, labeled 0, 1, 2, … …, N. Thus, the heaters and sensors are arranged in a side-by-side paired array. Each pair being a printing material level sensing device 6.

In the example of fig. 13B, the heaters 4 and sensors 5 are arranged in a vertically spaced, stacked array. Fig. 13C is a sectional view of fig. 13B, further showing a stacked arrangement of the heater 4 and sensor 5 pairs forming the printing material level sensing device 6.

In the above example, the heater of the printing material level sensing device may comprise a resistor. As an example, the heater may have a heating power of at least 10 mW. As a further example, the heater may have a heating power of less than 10W. The sensor may include a diode having a characteristic temperature response. For example, in one example, the sensor may include a P-N junction diode. In other examples, other diodes may be employed or other thermal sensors may be employed. For example, the sensor may include a resistor such as a metal thin film resistor. The resistor may, for example, be located between the heater and the marking material, for example by forming the resistor over the heater in the manufacturing stack.

In the above examples, the sensor of the printing material level sensing device is close enough to the associated heater to sense heat when the heater emits heat. For example, the sensor may be no more than 500 μm from the heater. In further examples, the sensor is no more than 20 μm from the heater. As one example, the sensor may be a metal thin film resistor layer formed less than 1 μm above the heater resistor layer in the fabrication stack. In such an example, the sensor resistor layer and the heater resistor layer may be separated by a dielectric layer.

In the above example, there may be at least five printing material level sensing devices in the printing material level sensor. As a further example, there may be at least ten printing material level sensing devices. As yet another example, there may be at least twenty printing material level sensing devices. For example, there may be at least one hundred printing material level sensing devices.

In the above examples, the heater and sensor may be supported on the rowbars. The strip 22 is shown in fig. 1, 2 and 13C. The strip may comprise silicon. The strip may have an aspect ratio (which is its length/width ratio) of at least 20.

In order to supply the electric power received from the power supply to each heater 4, a wiring 11 may be provided. As described above, the wiring 11 may be in the form of one or more metal traces, such as thin film metal traces, that transmit power from a power source to the heater. The metal traces may be formed on, for example, a strip by a silicon CMOS fabrication process. The metal traces may, for example, comprise aluminum. As an example, the metal traces may have a width no greater than 100 μm. The metal traces may have a length that is at least one hundred times their width. As an example, the metal traces may have a length of at least 10000 μm.

Fig. 13A to 13C additionally show examples of the pulse of the heater 4 of the printing material level sensing device 6 and the subsequent dissipation of heat by the adjacent material. In fig. 13A to 13C, the intensity of the heat decreases the further away from the heat source (i.e., the heater 4 of the printing material level sensing apparatus 6). The dissipation of heat is illustrated by the change in cross-hatching in fig. 13A to 13C.

While the apparatus, methods, and related aspects have been described with reference to certain examples, various modifications, changes, omissions, and substitutions can be made without departing from the spirit of the disclosure. Accordingly, it is intended that the apparatus, methods, and related aspects be limited only by the scope of the following claims and equivalents thereof. It should be noted that the above-mentioned examples illustrate rather than limit what is described herein, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

The word "comprising" does not exclude the presence of elements other than those listed in a claim and the word "a" or "an" does not exclude a plurality.

Features of any dependent claim may be combined with features of any of the independent or other dependent claims.