Measuring system for measuring toner level in cartridge of laser printer

Abstract

The disclosure relates to a measurement system for measuring toner levels in a cartridge of a laser printer. An apparatus includes an acceleration sensor, a charge change sensor, and processing circuitry. The acceleration sensor in operation generates an acceleration signal indicative of vibrations associated with the cartridge of the laser printer. The charge change sensor in operation generates a charge change signal indicative of an electrostatic charge change associated with a cartridge of the laser printer. Processing circuitry is coupled to the acceleration sensor and the charge change sensor. The processing circuitry, in operation, generates a characteristic parameter based on the acceleration signal and the charge change signal, and generates a level signal indicative of a level of toner in the cartridge based on the generated characteristic parameter. The generated characteristic parameters include a peak-to-peak distance of the acceleration signal and a maximum value of the charge change signal.

Description

Technical Field

[0001] The present disclosure relates to a measuring system for measuring the toner level in a cartridge of a laser printer. Furthermore, the present invention relates to a cartridge comprising the measuring system, a laser printer comprising the cartridge, a measuring method implemented by the measuring system and a corresponding computer program product. Background Art

[0002] Laser printers are a known and now common technology for printing on paper.

[0003] In particular, laser printing uses toner as a pigment, and the toner is contained in a powder state in a cartridge present in a laser printer.

[0004] The image to be reproduced from paper or an electronic carrier is impressed by a laser onto a photosensitive selenium drum, called an "OPC drum", which is charged by light radiation so that the image is captured in a negative manner and the toner is transferred to the paper, which is then fixed by melting.

[0005] Accurately detecting the amount of toner present in the cartridge is therefore a key action to ensure the correct operation of the laser printer. In fact, this allows the user to always be informed of the actual level of toner available for printing, allowing the cartridge to be replaced in the most appropriate way (i.e. only when the toner is almost exhausted, in order to minimize waste and costs, while at the same time not risking that a spare part will not be available when necessary).

[0006] There are several known solutions for measuring the level of toner in a cartridge. For example, it is known to use an inductive sensor to detect the level of toner powder.

[0007] However, known solutions do not ensure accurate and reliable measurements (in particular, several critical issues are known in their production, which may cause problems in the final product) and generally do not allow precise detection of the toner level (usually, the measured level is indicated to the user as "full", "medium" or "low"). Summary of the Invention

[0008] In one embodiment, a device includes an acceleration sensor that generates an acceleration signal indicative of vibration associated with a cartridge of a laser printer; a charge change sensor that generates a charge change signal indicative of electrostatic charge changes associated with the cartridge of the laser printer; and processing circuitry coupled to the acceleration sensor and the charge change sensor. The processing circuitry generates characteristic parameters based on the acceleration signal and the charge change signal, and generates a level signal indicative of a toner level in the cartridge based on the generated characteristic parameters. The generated characteristic parameters include a peak-to-peak distance of the acceleration signal and a maximum value of the charge change signal.

[0009] In one embodiment, a system includes a laser printer cartridge having an external body; and a toner level measurement circuit device coupled to the external body, wherein the toner level measurement circuit device, in operation, generates an acceleration signal indicative of vibration associated with the laser printer cartridge; generates a charge change signal indicative of electrostatic charge changes associated with the laser printer cartridge; generates characteristic parameters based on the acceleration signal and the charge change signal; and generates a level signal indicative of a toner level in the laser printer cartridge based on the generated characteristic parameters. The generated characteristic parameters include a peak-to-peak distance of the acceleration signal and a maximum value of the charge change signal.

[0010] In an embodiment, a method includes generating an acceleration signal indicative of vibration associated with a laser printer cartridge; generating a charge variation signal indicative of electrostatic charge variation associated with the laser printer cartridge; generating characteristic parameters based on the acceleration signal and the charge variation signal; and generating a level signal indicative of a toner level in the laser printer cartridge based on the generated characteristic parameters. The generated characteristic parameters include a peak-to-peak distance of the acceleration signal and a maximum value of the charge variation signal.

[0011] In one embodiment, the contents of a non-transitory computer-readable medium configure a processing circuit device to perform a method comprising: generating an acceleration signal indicative of vibration associated with a laser printer cartridge; generating a charge change signal indicative of a change in electrostatic charge associated with the laser printer cartridge; generating characteristic parameters based on the acceleration signal and the charge change signal; and generating a level signal indicative of a level of toner in the laser printer cartridge based on the generated characteristic parameters. The generated characteristic parameters include a peak-to-peak distance of the acceleration signal and a maximum value of the charge change signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] For a better understanding of the present disclosure, embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which:

[0013] Figure 1 is a schematic cross-sectional view of an assembly of a cartridge for a laser printer according to one embodiment;

[0014] Figure 2 According to one embodiment, Figure 1 A perspective schematic diagram of a cartridge for a laser printer in dotted form;

[0015] Figure 3 is a schematic diagram showing a method for measuring Figure 1 A block diagram of details of a system for measuring the toner level of a cartridge;

[0016] Figure 4 is a schematic diagram showing a method for measuring Figure 1 A block diagram of the classification criteria for the toner levels of the cartridges;

[0017] Figure 5 Shown by Figure 4 An example of a confusion matrix obtained with the classification criteria ; and

[0018] Figure 6 is a schematic diagram showing a method of Figure 3 Block diagram of the measurement method performed by the measurement system.

[0019] In the following description, elements common to different embodiments are denoted by the same reference numerals. DETAILED DESCRIPTION

[0020] Figure 1 A cartridge 10 is shown for a laser printer. Figure 2 It is shown with reference numeral 40 in FIG.

[0021] The cartridge 10 is configured to contain toner 12 , in particular, powder of the toner 12 , for use in printing on paper.

[0022] The general construction of the cassette 10 is of a known type.

[0023] In particular, the cartridge 10 includes an outer body 14 (eg, a container) that houses components such as a toner reservoir 16 , a stir bar 18 , a developer roller 20 , an OPC drum 22 , a primary charge roller (PCR) 24 , a wiper blade 26 , and a waste bin 28 .

[0024] The toner tank 16 contains toner 12 to be used for printing. Specifically, powder of the toner 12 is kept moving within the toner tank 16 by a stirring rod 18 , which is also present inside the toner tank 16 and is configured to rotate so as to continuously move the toner 12 .

[0025] The developer roller 20 is disposed in the opening of the toner sump 16 and is interposed between the toner sump 16 and the OPC drum 22. The developer roller 20 allows the toner 12 to be selectively transferred onto the OPC drum 22 by rotating axially in a controlled manner.

[0026] The PCR 24 is in contact with the OPC drum 22 and is configured to negatively charge an outer photosensitive surface of the OPC drum 22 , to which the toner 12 is then transferred by the developer roller 20 .

[0027] Through the laser opening 30 present in the outer body 14, the laser beam 32 can enter the outer body 14 and be incident on the OPC drum 22, so that an image that is a negative image of the image to be printed is imprinted on the outer photosensitive surface of the OPC drum 22. In particular, this prevents the toner 12 from adhering to the outer photosensitive surface of the OPC drum 22 at the hidden image.

[0028] Furthermore, the wiping blade 26 is in contact with the OPC drum 22 so as to remove any residues of toner 12 that may have erroneously adhered to the OPC drum 22 after the OPC drum came into contact with the paper to be printed and therefore not been transferred to the paper. These residues of toner 12 that have been detached by the wiping blade 26 end up in the waste bin 28, with the wiping blade 26 facing the waste bin.

[0029] In use and in a manner known per se, laser printing comprises the following steps which succeed one another.

[0030] The step of electrostatically charging the OPC drum 22 is performed by the PCR 24. In detail, the continuous flow of electric current from the PCR 24 produces a negative charge state on the photosensitive surface of the OPC drum 22.

[0031] In the exposure step, the laser beam 32 scans the surface of the OPC drum 22, thereby removing the negative charge in the area that does not need to be printed, that is, in the subsequent development step, the toner 12 will not need to adhere to this area. Therefore, at this time, there is a latent image on the surface of the OPC drum 22, which is the same as the negative reproduction of the image to be printed on the paper.

[0032] In the development step, deposition of powder of toner 12 is performed on the latent image of the OPC drum 22. Powder of toner 12 from the toner reservoir 16 is electrically attracted to the OPC drum 22 and sticks to areas that remain sensitive to negative charges.

[0033] In the transfer step, the OPC drum 22 slides on the paper charged in a positive manner by the transfer roller of the laser printer 40 so that the toner 12 is attracted to the paper and transferred thereto, thereby forming an image to be printed.

[0034] In the fusing step, the toner 12 particles placed on the paper are melted on the paper. Specifically, the paper passes through a portion of the laser printer 40 called a "fusing unit," which includes an upper fusing roller and a lower fusing roller. A lower pressure roller presses the paper against the upper fusing roller, which is heated to melt the toner 12, thereby adhering the toner to the paper.

[0035] In a subsequent cleaning step, the toner 12 remaining on the OPC drum 22 after the paper has passed is cleaned off, allowing the machine to repeat the printing process.

[0036] Finally, in an erasing step, the cartridge 10 erases any traces of negative charge still present on the developer roller 20 .

[0037] Figure 2 A laser printer 40 is shown which includes a cartridge 10 and further elements which are known and therefore not described in detail, such as: a drive roller 42 which brings the paper to be printed (indicated here by reference numeral 41) to the cartridge 10; a transfer roller 44 which charges the paper 41 in a positive manner where it contacts the OPC roller 22; a fusing unit 46 having an upper fusing roller 46a and a lower pressure roller 46b for fusing the toner 12 to the paper 41; and a laser assembly 48 which includes a laser emitter 48a for emitting a laser beam 32 and a rotating mirror 48b for directing the laser beam 32 into the laser opening 30 of the cartridge 10.

[0038] As previously described, the cartridge 10 has several rotating elements (e.g., OPC drum 22, developer roller 20, PCR 24, etc.) that, during use, rotate, for example, axially about respective axes of rotation. Thus, the cartridge 10 is configured to generate vibrations during its use that are measurable.

[0039] Furthermore, due to its rotation, the stirring rod 18, in use, generates movement of the particles of the toner 12 in order to prevent them from being compacted against one another and thereby making it difficult for them to be transferred toward the OPC drum 22. However, since the toner 12 contains approximately 5-6% ferromagnetic material (e.g., iron oxide), it has been demonstrated that the movement of the toner 12 by the stirring rod 18 generates electrostatic charge changes that are also measurable.

[0040] In particular, and as better described below, applicants have determined that the vibrations and electrostatic charge changes generated by cartridge 10 correlate with the amount of toner 12 present in toner sump 16. Thus, the level of toner 12 in cartridge 10 can be measured by analyzing measurements of the vibrations and / or electrostatic charge changes generated by cartridge 10.

[0041] For this purpose, and as Figure 3 As better shown in FIG, the cartridge 10 includes a measurement system 50 for measuring the level of toner 12 in the cartridge 10.

[0042] The measurement system includes an acceleration sensor 52 , a charge change sensor 54 , or both the acceleration sensor 52 and the charge change sensor 54 .

[0043] The acceleration sensor 52 comprises an accelerometer (eg, a three-axis accelerometer) configured to measure acceleration corresponding to vibrations generated by rotating elements of the cartridge 10 during use.

[0044] In particular, the acceleration sensor 52 generates, in use, an acceleration signal indicative of vibrations produced by the cartridge 10. For example, the acceleration signal comprises, at each instant in time, a respective acceleration value for each acceleration component measured by the acceleration sensor 52, e.g., a respective acceleration value for each of the measurement axes of the accelerometer.

[0045] For purposes of illustration and not limitation, the acceleration sensor 52 may comprise the applicant's accelerometer LIS2DUXS12 having, for example, an "output data rate" (ODR) equal to approximately 200 Hz.

[0046] Specifically, the acceleration sensor 52 is carried by the outer body 14 of the case 10 and is fixed to the outer body. For example, the acceleration sensor 52 is arranged outside the outer body 14 and is fixed to the outer surface of the outer body 14.

[0047] In more detail, the acceleration sensor 52 is fixed to a region of the outer body 14 of the cartridge 10 that is positioned at a rotating element of the cartridge 10 (e.g., at the OPC drum 22). For example, the region of the outer body 14 to which the acceleration sensor 52 is fixed may be a portion of the outer body 14 that is closest to the rotating element of the cartridge 10. Figure 1 As shown in FIG.

[0048] The charge change sensor 54 is configured to measure a change in charge (in detail, electrostatic charge) generated by the toner 12 due to the movement made by the stirring bar 18 .

[0049] In particular, the charge change sensor 54 generates a charge change signal indicative of a change in electrostatic charge generated by the cartridge 10 during use.

[0050] For purposes of illustration and not limitation, the charge change sensor 54 may comprise the applicant's LIS2DUXS12, for example, having an "output data rate" (ODR) equal to approximately 200 Hz.

[0051] In detail, the charge change sensor 54 is carried by the outer body 14 of the cartridge 10 and is fixed to the outer body. For example, the charge change sensor 54 is arranged outside the outer body 14 and is fixed to the outer surface of the outer body 14.

[0052] In more detail, the charge change sensor 54 is fixed to an area of ​​the outer body 14 of the cartridge 10 that is located at the toner reservoir 16 and, in more detail, at the stirring rod 18. For example, the area of ​​the outer body 14 to which the charge change sensor 54 is fixed may be a portion of the outer body 14 that is closest to the stirring rod 18 of the cartridge 10. Figure 1 As shown in FIG.

[0053] Specifically, the charge change sensor 54 includes one or more electrodes (not shown).

[0054] As previously described, the electrode of the charge change sensor 54 is disposed within the cartridge 10. In detail, the electrode is arranged to face the toner reservoir 16 and may be electrically shielded toward the exterior of the cartridge 10 (e.g., a metal portion of the electrode extends between the outer body 14 and an insulating layer that electrically insulates the electrode from the environment surrounding the cartridge 10, thereby making it exclusively or in any case primarily sensitive to electrostatic charge changes generated by the cartridge 10).

[0055] In use, the electrodes detect electrostatic charge changes and generate corresponding charge change signals indicative of the measured electrostatic charge changes.

[0056] In addition, the measurement system 50 includes a control unit or circuit 56, which is configured to receive an acceleration signal from the acceleration sensor 52 and / or a charge change signal from the charge change sensor 54, and based on the acceleration signal and / or the charge change signal, generate a level signal indicating the level of the colorant 12 in the box 10 (in detail, indicating the amount of colorant 12 present in the colorant storage tank 16 and available for printing).

[0057] Hereinafter, a case is exemplarily considered in which the control unit or circuit 56 is outside the acceleration sensor 52 and the charge change sensor 54 and is operatively coupled (in detail, electrically coupled) to the acceleration sensor 52 and the charge change sensor 54. Figure 3 Shown in.

[0058] However, according to various embodiments, the control unit 56 may be a control unit integrated into the acceleration sensor 52 and / or the charge change sensor 54. For example, the control unit 56 may be internal to the acceleration sensor 52 and operatively coupled to the charge change sensor 54 to obtain a charge change signal from the charge change sensor. This allows for full utilization of the electronic circuitry included in modern sensors without requiring the use of a control unit external to the sensor.

[0059] The control unit 56 is an electronic unit or circuit (such as a CPU, a microprocessor, a microcontroller or a dedicated computing unit), which may include units of known types and not shown coupled to each other, such as: an interface unit or circuit (for example, including an amplification stage and / or an analog-to-digital converter ADC stage) for connecting the acceleration sensor 52 and the charge change sensor 54 to the control unit 56; a processing unit or circuit for processing signals from the acceleration sensor 52 and the charge change sensor 54; and a data storage unit or memory (such as a memory, for example a non-volatile memory) for storing the acquired data.

[0060] In detail, the control unit 56 is carried by the outer body 14 of the box 10, for example, the control unit is fixed to the outer body. For example, the control unit 56 is arranged outside the outer body 14, and the control unit is fixed to the outer surface of the outer body 14. Figure 1 Furthermore, and in a manner not shown, the control unit 56 may be coupled to the acceleration sensor 52 and the charge change sensor 54 via electrical connections (eg, cables).

[0061] like Figure 3 As shown in , the control unit 56 (e.g., the processing unit of the control unit 56) includes: a pre-processing module or circuit 60 (optional), a filtering module or circuit 62 (optional), a feature extraction module or circuit 64 and a classification module or circuit 66.

[0062] The pre-processing module 60 is coupled to the acceleration sensor 52 to receive the acceleration signal from the acceleration sensor. The pre-processing module 60 is configured to pre-process the acceleration signal, specifically calculating the corresponding norm of the acceleration value considered on the measurement axis of the accelerometer at each acquisition moment of the acceleration signal, so as to obtain a (pre-processed) acceleration signal that is independent of the position and spatial orientation of the acceleration sensor 52.

[0063] A filtering module (also referred to as a charge change filtering module) 62 is coupled to the charge change sensor 54 to receive a charge change signal from the charge change sensor. The filtering module 62 is configured to filter the charge change signal, for example, by filtering it through a bandpass filter having a lower cutoff frequency (inclusive between about 0.1 Hz and about 1 Hz, and for example, equal to about 0.5 Hz) and an upper cutoff frequency (inclusive between about 5 Hz and about 20 Hz, and for example, equal to about 5 Hz). In this manner, the (filtered) charge change signal is not dependent on factors such as charge changes caused by the 50 Hz or 60 Hz power supply present in a closed environment (such as the interior of a building) or used to power the printer 40.

[0064] The feature extraction module 64 is coupled to the pre-processing module 60 and / or the filtering module 62 to receive the acceleration signal (pre-processed) and / or the charge change signal (filtered) from the pre-processing module and the filtering module, respectively. The feature extraction module 64 is configured to generate feature parameters indicating features of the acceleration signal and / or the charge change signal.

[0065] For purposes of illustration and non-limiting purposes, the features considered are one or more of the following: mean, variance, energy, zero crossing, peak detector, peak-to-peak distance, minimum, and maximum. For example, variance, zero crossing, peak detector, and peak-to-peak distance may be used; mean, peak detector, peak-to-peak distance, minimum, and maximum may be used. For example, in the case of considering the use of both an acceleration signal and a charge change signal, peak-to-peak distance may be used for the acceleration signal and maximum value may be used for the charge change signal, and possibly other features previously mentioned for both signals may also be used.

[0066] Therefore, the feature extraction module 64 is configured to calculate features of the selected acceleration signal and / or charge variation signal and generate feature parameters accordingly.

[0067] For example, considering that the ODR of the acceleration sensor 52 and the charge change sensor 54 is equal to about 200 Hz, the calculation of the characteristics can be completed based on the acquisition of several hundred samples (for example, about 255) of the acceleration signal and the charge change signal.

[0068] The classification module 66 is coupled to the feature extraction module 64 to receive the feature parameters of the acceleration signal and / or the charge change signal from the feature extraction module. The classification module 66 is configured to generate a level signal based on the feature parameters of the acceleration signal and / or the charge change signal, and is therefore configured to determine the level of the toner 12 in the cartridge 10 based on the feature parameters.

[0069] In detail, the level signal can have values ​​between a plurality of defined values ​​or thresholds corresponding to a plurality of defined levels of toner 12 in the cartridge 10 (specifically, in the toner sump 16). For example, the value of the level signal can vary between five possible defined values ​​or thresholds, such as 0%, 25%, 50%, 75%, and 100%. Each of these values ​​identifies a corresponding level to which the amount of toner 12 detected by the acceleration signal and / or the charge change signal may belong. For example, if the acceleration signal and / or the charge variation signal indicates a percentage amount (e.g., x) of the toner 12 in the toner storage tank 16 included in a first variation range (e.g., 0% ≤ x < 12.5%), the horizontal signal assumes a first value (e.g., 0%) indicating a first horizontal level; if the percentage amount is included in a second variation range (e.g., 12.5% ​​≤ x < 37.5%), the horizontal signal assumes a second value (e.g., 25%) indicating a second horizontal level; if the percentage amount is included in a third variation range (e.g., 12.5% ​​≤ x < 37.5%), the horizontal signal assumes a second value (e.g., 25%) indicating a second horizontal level. if the percentage amount is included in a fourth variation range (for example, 62.5%≤x<87.5%), the horizontal signal presents a fourth value (for example, 75%) indicating a fourth horizontal level; and if the percentage amount is included in a fifth variation range (for example, 87.5%≤x≤100%), the horizontal signal presents a fifth value (for example, 100%) indicating a fifth horizontal level.

[0070] Specifically, the classification module 66 generates a level signal based on the characteristic parameters using machine learning or artificial intelligence techniques. Specifically, the classification module 66 implements a classification algorithm, such as a "random forest" (RF) classifier, a "decision tree" (DT) classifier, or a "support vector machine" (SVM) classifier. Hereinafter, the case where the classification module 66 implements a DT classifier is exemplified.

[0071] The classifier is trained in a supervised manner and according to techniques known per se in order to recognize, given characteristic parameters received at input, to which predefined level class the performed measurement belongs, in order to select the value of the level signal accordingly.

[0072] For example, when only the acceleration signal is used, the DT classifier can have a number of leaves equal to approximately 6 and a tree size equal to approximately 11; when only the charge change signal is used, the DT classifier can have a number of leaves equal to approximately 11 and a tree size equal to approximately 21; and when both the acceleration signal and the charge change signal are used, the DT classifier can have a number of leaves equal to approximately 6 and a tree size equal to approximately 11.

[0073] Generally, three different embodiments of the previously described measurement system 50 are described.

[0074] In the first embodiment, the measurement system 50 includes the acceleration sensor 52 but does not include the charge change sensor 54. In this case, the control unit 56 does not include the filtering module 62, so the feature extraction module 64 and the classification module 66 operate only based on the acceleration signal and the resulting feature parameters.

[0075] In the second embodiment, the measurement system 50 includes a charge change sensor 54, but no acceleration sensor 52. In this case, the control unit 56 does not include the pre-processing module 60, so the feature extraction module 64 and the classification module 66 operate only based on the charge change signal and the resulting feature parameters.

[0076] In a third embodiment, the measurement system 50 includes both an acceleration sensor 52 and a charge change sensor 54. In this case, the control unit 56 may include both a filtering module 62 and a pre-processing module 60, and typically, a feature extraction module 64 and a classification module 66 operate based on both the acceleration signal and the charge change signal (thus in a "data fusion" mode) and the resulting feature parameters.

[0077] In particular, in the third embodiment, the feature extraction module 64 may calculate the peak-to-peak distance of the acceleration signal (e.g., after preprocessing by the preprocessing module 60) and the maximum value of the charge change signal (e.g., the filtered charge change signal output by the filtering module 62). In addition, the classification module 66 may use a DT classifier as a classification algorithm (e.g., with the number of leaves equal to approximately 6 and the tree size equal to approximately 11).

[0078] In this case, the DT classifier is based on Figure 4 The classification criteria are shown in .

[0079] Specifically, in step D1, the DT classifier examines the peak-to-peak distance of the acceleration signal (also referred to below as distance A for simplicity) pp ) satisfies the first condition, for example, A pp Is it less than or equal to the first threshold distance A1. For example, the first threshold distance A1 may be equal to approximately 0.306 mg, or equal to approximately 0.306396 mg.

[0080] If the first condition is met (exit from D1 with “Yes”, e.g., distance A pp is less than or equal to the first threshold distance A1), then in step D2, the DT classifier checks the distance A pp Whether the second condition is met, for example, A ppIs it less than or equal to the second threshold distance A2. For example, the second threshold distance A2 may be equal to approximately 0.141 mg, or equal to approximately 0.141358 mg.

[0081] If the second condition is met (exit from D2 with “Yes”, e.g., distance A pp is less than or equal to a second threshold distance A2), then in step D3, the DT classifier determines (estimates) that the level of toner 12 in cartridge 10 corresponds to a first toner level T1, eg, equal to approximately 100%.

[0082] If the second condition is not met (exit from D2 with "No", for example, distance A pp is greater than the second threshold distance A2), then in step D4, the DT classifier checks the maximum value of the (filtered) charge change signal (also referred to as maximum value C in the following for simplicity) m ) whether the third condition is met, for example, C m Is it less than or equal to the first threshold maximum value C1. For example, the first threshold maximum value C1 may be equal to approximately 1.463LSB, or equal to approximately 1.463375LSB.

[0083] If the third condition is not met (exit from D4 with "No", for example, the maximum value C m is greater than the first threshold maximum value C1), then in step D6 the DT classifier determines that the level of toner 12 in the cartridge 10 corresponds to a third toner level T3, for example, equal to about 50%.

[0084] If the third condition is met (exit from D4 with “Yes”, e.g., the maximum value C m is less than or equal to the first threshold maximum value C1), then in step D5, the DT classifier checks the distance A pp Whether the fourth condition is met, for example, A pp Is it less than or equal to the third threshold distance A3. For example, the third threshold distance A3 may be equal to approximately 0.193 mg, or equal to approximately 0.193359 mg.

[0085] If the fourth condition is met (exit from D5 "Yes", i.e. distance A pp is less than or equal to a third threshold distance A3), then in step D7, the DT classifier determines that the level of toner 12 in the cartridge 10 corresponds to a third toner level T3, specifically, equal to about 50%.

[0086] If the fourth condition is not met (exit from D5 "No", i.e., distance A pp is greater than a third threshold maximum value A3), then in step D8 the DT classifier determines that the level of toner 12 in the cartridge 10 corresponds to a second toner level T2, in particular, equal to about 75%.

[0087] If the first condition is not met (exit from D1 with “No”, i.e., distance A pp is greater than the first threshold distance A1), then in step D9, the DT classifier checks the distance A pp Whether the fifth condition is satisfied, specifically, whether the distance is less than or equal to the fourth threshold distance A4. In particular, the fourth threshold distance A4 is equal to approximately 0.460 mg, in particular, equal to approximately 0.46045 mg.

[0088] If the fifth condition is met (exit from D9 "Yes", i.e. distance A pp is less than or equal to a fourth threshold distance A4), then in step D10, the DT classifier determines that the level of toner 12 in the cartridge 10 corresponds to a fourth toner level T4, specifically, equal to about 25%.

[0089] If the fifth condition is not met (exit from D9 "No", i.e., distance A pp is greater than a fourth threshold maximum value A4), then in step D11 the DT classifier determines that the level of toner 12 in the cartridge 10 corresponds to a fifth toner level T5, in particular, equal to about 0%.

[0090] therefore, Figure 4 The classification criteria allow the level of toner 12 in the cartridge 10 to be classified according to five predefined values, namely T1 to T5.

[0091] Specifically, the following relationship exists between predefined toner values ​​T1 to T5: T1 > T2 > T3 > T4 > T5.

[0092] Furthermore, the following relationship exists between the threshold distances A1 to A4: A2 <A3<A1<A4。

[0093] Figure 5 It shows that the third embodiment can be used Figure 4 An example of a confusion matrix obtained for the classification criteria of . In particular, indices a to e correspond to toner levels T5 to T1.

[0094] Because you can Figure 5 Extrapolating this, the use of data from both acceleration sensor 52 and charge change sensor 54 significantly and surprisingly improves classification accuracy to approximately 94.191%. In fact, it was demonstrated that while acceleration sensor 52 alone has low accuracy and sensitivity when evaluating the difference between toner levels of 50% and 75%, charge change sensor 54 provides additional information that allows this distinction to be made with high accuracy and sensitivity. Thus, the combined use of these two sensors significantly increases measurement reliability.

[0095] Figure 6A measurement method 80 is shown that is performed by the control unit 56 to detect the level of toner 12 in the cartridge 10 .

[0096] At step S10 of the measurement method 80 , the control unit 56 acquires an acceleration signal from the acceleration sensor 52 .

[0097] At step S12 of measurement method 80 , control unit 56 acquires a charge variation signal from charge variation sensor 54 .

[0098] Steps S10 and S12 may be performed independently or in combination with each other, similar to what was previously described with reference to the measurement system 50. Hereinafter, a case where the measurement method 80 performs detection of the level of the toner 12 using both the acceleration signal and the charge variation signal is exemplarily described.

[0099] At step S14 (optional) of the measurement method 80 , the control unit 56 pre-processes the acceleration signal in detail by means of the pre-processing module 60 described previously, thereby calculating the norms of the components of the acceleration signal.

[0100] At step S16 (optional) of the measurement method 80 , the control unit 56 filters the charge variation signal via the previously described filtering module 62 .

[0101] At step S18 of the measuring method 80 , the control unit 56 determines characteristic parameters based on the acceleration signal (in detail, pre-processed) and the charge change signal (in detail, filtered), in detail by means of the previously described feature extraction module 64 .

[0102] At step S20 of the measuring method 80 , the control unit 56 generates a level signal based on the characteristic parameters, in detail through the classification module 66 described previously.

[0103] The level signal may be provided to a user, for example, by a visual or auditory message generated by a user interface (not shown) that is coupled to and controlled by the control unit 56, or the level signal may be used by the control unit 56 to control one or more functions of the box 10 or printer 40 (or possibly other electronic devices coupled to the control unit 56).

[0104] Furthermore, the measuring method 80 is executed by the control unit 56 by means of a suitable computer program product which is stored in the control unit 56 and is designed such that, when executed in the control unit 56 , the control unit becomes configured to perform the measuring method 80 .

[0105] From an examination of the features of the present disclosure made in accordance with the present disclosure, the advantages it offers are apparent.

[0106] In detail, the measurement system 50 and the measurement method 80 allow for accurate and precise detection of the level of toner 12 present in the cartridge 10 of the laser printer 40 , such that a user is provided with a reliable indication of the amount of toner 12 still available for printing.

[0107] The measurement system 50 comprises elements with high measurement reliability and low cost (from both a financial and an energy point of view), thus it allows the level of the toner 12 to be measured in a reliable, economical manner and with reduced energy consumption.

[0108] In particular, both measurement channels (acceleration sensor 52 and charge change sensor 54 ) are used in order to minimize the computational, energy and economic costs of the measurement system 50 , or both measurement channels may be used in order to maximize measurement accuracy.

[0109] In fact, considering the number of leaves and branches of the classification tree previously indicated as the size of the DT classifier for exemplary purposes, it has been demonstrated that an embodiment of the measurement system 50 including only the acceleration sensor 52 allows for an accuracy of approximately 84%, while an embodiment of the measurement system 50 including only the charge change sensor 54 allows for an accuracy of approximately 86%. On the other hand, an embodiment of the measurement system 50 including both the acceleration sensor 52 and the charge change sensor 54 allows for an accuracy of approximately 94% (approximately 8% to 10% greater than the accuracy achieved when using only one of the sensors 52 and 54). Furthermore, it has been demonstrated that when using two measurement channels, the computational complexity (e.g., the complexity of the DT classifier, e.g., in terms of the features used and the tree size) is reduced relative to the case of using only the charge change sensor 54 and is fully comparable to the case of using only the acceleration sensor 52, thereby reducing overfitting of the classifier. This demonstrates the correlation between the acceleration signal and the charge change signal, as both depend on the level of toner 12 in the cartridge 10.

[0110] Furthermore, when both sensors 52 and 54 are used, it is also possible to utilize the two previously described features (A pp and C m ) to achieve such high accuracy values; since a reduced number of features are sufficient to obtain these high accuracy values, computing resources and time / power consumption are also minimized.

[0111] Furthermore, the measurement system 50 can be easily integrated in currently known cartridges 10 and does not require significant modifications to the cartridge.

[0112] Finally, it is clear that modifications and variations may be made to the present disclosure as herein described and illustrated without departing from the scope of the present disclosure as hereby defined in the appended claims.

[0113] For example, the different described embodiments may be combined with each other to provide further solutions.

[0114] Furthermore, the pre-processing module 60 may not be present, for example, because the calculation of the norm is already performed inside the acceleration sensor 52 and therefore the acceleration signal at the output of the acceleration sensor 52 already indicates the norm of the measurement carried out on the measurement axis of the accelerometer. Furthermore, the same norm calculation may not be performed by the pre-processing module 60 or the acceleration sensor 52, for example because the accelerometer present in the acceleration sensor 52 is of the single-axis type or is positioned relative to the case 10 so as to have only one axis stimulated by the vibrations caused by the case 10. In this case, the feature extraction module 64 can operate directly on the signal measured by the accelerometer and is therefore not based on the measured norm.

[0115] Furthermore, a filtering module 62 may be present. In this case, the filtering of the charge variation signal may be performed internally to the charge variation sensor 54, or the filtering may not be performed. In this second case, the feature extraction module 64 may operate directly on the signal measured by the electrodes and therefore not be based on a filtered signal.

[0116] Furthermore, although the previously described feature extraction module 64 is coupled to both the pre-processing module 60 and the filtering module 62 and is therefore configured to determine the feature parameter based on both the acceleration signal and the charge change signal, it will be apparent that the feature extraction module 64 may be formed by a first feature extraction module (not shown) coupled only to the pre-processing module 60 and therefore configured to determine the first feature parameter based only on the acceleration signal, and a second feature extraction module (not shown) coupled only to the filtering module 62 and therefore configured to determine the second feature parameter based only on the charge change signal. In this case, both the first feature extraction module and the second feature extraction module are coupled to the classification module 66, which receives both the first feature parameter and the second feature parameter in use to generate a level signal similar to the level signal previously described.

[0117] In addition, and in a manner not shown, the pre-processing module 60 may also implement a filter configured to filter the acceleration signal in order to remove any noise or select specific frequency components of the acceleration signal. In detail, this filtering may be performed, and after filtering, the acceleration signal (filtered) may be pre-processed as previously described. For example, this filtering may be performed by another bandpass filter having a lower cutoff frequency (included between approximately 0.5 Hz and approximately 10 Hz, and for example, equal to approximately 5 Hz) and an upper cutoff frequency (included between approximately 50 Hz and approximately 100 Hz, and for example, equal to approximately 80 Hz).

[0118] Alternatively, this filtering of the acceleration signal can also be performed outside the pre-processing module 60 and therefore performed by another filtering module (also called acceleration filtering module, not shown), which is coupled to the acceleration sensor 52 to receive the acceleration signal from the acceleration sensor and is also coupled to the pre-processing module 60 to provide the pre-processing module with the acceleration signal that is filtered and can be pre-processed as previously described.

[0119] In an embodiment, a measurement system (50) for a cartridge (10) of a laser printer (40) is configured to be coupled to an outer body (14) of the cartridge (10) and includes at least one of the following: an acceleration sensor (52) configured to measure vibrations of the cartridge (10), the vibrations of the cartridge (10) being generated by rotating elements (20, 22, 24) of the cartridge (10) and being dependent on the level of toner (12) contained in the cartridge (10); and a charge change sensor (54) configured to measure electrostatic charge changes, the electrostatic charge changes being generated by the cartridge ( The measurement system is configured to measure the level of the toner (12) in the cartridge (10) and to determine a characteristic parameter based on the acceleration signal and / or the charge change signal; and to generate a level signal indicating the level of the toner (12) in the cartridge (10) based on the characteristic parameter.

[0120] In an embodiment, the control unit (56) includes: a feature extraction module (64) coupled to the acceleration sensor (52) and / or the charge change sensor (54) and configured to determine the feature parameter; and a classification module (66) coupled to the feature extraction module (64) and configured to generate the level signal.

[0121] The control unit (56) may be integrated into one of the acceleration sensor (52) and the charge change sensor (54) and may be operatively coupled to the other of the acceleration sensor (52) and the charge change sensor (54), or the control unit (56) may be external to the acceleration sensor (52) and the charge change sensor (54) and may be operatively coupled to the acceleration sensor (52) and the charge change sensor (54).

[0122] In an embodiment, a cartridge (10) for a laser printer (40) includes an outer body (14) and a measurement system (50) coupled to the outer body (14).

[0123] In an embodiment, the rotating elements (20, 22, 24) of the cartridge may include one or more of the following items housed in the outer body (14): a developer roller (20), an OPC drum (22), and a primary charging roller (24), wherein the cartridge (10) may also include a toner reservoir (16) and a stirring rod (18), the toner reservoir being configured to hold toner (12) and being housed in the outer body (14), the stirring rod extending into the toner reservoir (16) and being configured to rotate in the toner reservoir (16) such that the toner (12) moves into the toner reservoir (16), the acceleration sensor (52) may be located at the rotating elements (20, 22, 24), and the charge change sensor (54) may be located at the toner reservoir (16).

[0124] In an embodiment, a laser printer (40) includes a cartridge (10).

[0125] In an embodiment, a measurement method (80) for measuring the level of toner (12) in a cartridge (10) of a laser printer (40) is performed by a measurement system (50) configured to be coupled to an outer body (14) of the cartridge (10) and comprising at least one of the following: an acceleration sensor (52) configured to measure vibrations of the cartridge (10), the vibrations of the cartridge (10) being generated by rotating elements (20, 22, 24) of the cartridge (10) and being dependent on the level of toner (12) in the cartridge (10); and a charge change sensor (54) configured to measure electrostatic charge changes, the electrostatic charge changes being generated by the movement of the toner (12) in the cartridge (10). The vibration is generated and depends on the level of the toner (12) in the box (10), the measuring system (50) also includes a control unit (56), and the measuring method (80) includes the following steps: the control unit (56) receives (S10, S12) an acceleration signal indicating the measured vibration from the acceleration sensor (52), and / or receives a charge change signal indicating the measured electrostatic charge change from the charge change sensor (54); the control unit (56) determines (S18) a characteristic parameter based on the acceleration signal and the charge change signal; and / or the control unit (56) generates (S20) a level signal indicating the level of the toner (12) in the box (10) based on the characteristic parameter.

[0126] The step of generating (S20) the level signal may include selecting a value of the level signal among a plurality of predefined values ​​corresponding to a respective plurality of predefined levels of toner (12) in the cartridge (10).

[0127] The step of generating ( S20 ) the level signal may comprise processing the characteristic parameters by means of a classifier, in particular a classifier of the decision tree type.

[0128] The step of determining (S18) characteristic parameters may include calculating one or more of the following characteristics based on the acceleration signal and / or the charge change signal: mean, variance, energy, "zero crossing", "peak detector", peak to peak distance, minimum, maximum.

[0129] The measuring method may further comprise the step of pre-processing (S14) the acceleration signal by calculating a norm of the acceleration signal, and the step of determining (S18) the characteristic parameter may comprise determining the characteristic parameter from the pre-processed acceleration signal.

[0130] The measuring method may further comprise the step of filtering ( S16 ) the charge variation signal, and the step of determining ( S18 ) the characteristic parameter may comprise determining the characteristic parameter from the filtered charge variation signal.

[0131] The step of filtering the charge variation signal (S16) may include using a bandpass filter having a lower cutoff frequency between 0.1 Hz and 1 Hz and an upper cutoff frequency between 5 Hz and 20 Hz.

[0132] In an embodiment, a computer program product is storable in a control unit (56) and is designed such that, when executed in the control unit (56) thereof, the control unit (56) becomes configured to perform the measurement method (80).

[0133] In an embodiment, a device includes: an acceleration sensor that generates an acceleration signal indicative of vibration associated with a cartridge of a laser printer; a charge change sensor that generates a charge change signal indicative of a change in electrostatic charge associated with the cartridge of the laser printer; and a processing circuit device coupled to the acceleration sensor and the charge change sensor; wherein the processing circuit device, in operation, generates a characteristic parameter based on the acceleration signal and the charge change signal; and generates a level signal indicative of the level of toner in the cartridge based on the generated characteristic parameter.

[0134] In an embodiment, the processing circuitry comprises: a feature extraction module, in operation, to generate feature parameters; and a classification module, coupled to the feature extraction module, wherein, in operation, the classification module generates a level signal.

[0135] In an embodiment, the apparatus comprises an integrated circuit comprising: processing circuitry; processing circuitry and an acceleration sensor; processing circuitry and a charge change sensor; or processing circuitry, an acceleration sensor, and a charge change sensor.

[0136] In an embodiment, the processing circuitry is operable to determine a norm of the acceleration signal, thereby generating a normalized acceleration signal, and to generate the characteristic parameter based on the normalized acceleration signal.

[0137] In an embodiment, the charge change sensor includes a filter that filters the charge change signal to generate a filtered charge change signal, and the processing circuitry is operable to generate the characteristic parameter based on the filtered charge change signal. In an embodiment, the filter is a bandpass filter.

[0138] In an embodiment, the acceleration sensor comprises a filter operable to filter the acceleration signal to generate a filtered acceleration signal, and the processing circuitry is operable to generate the characteristic parameter based on the filtered acceleration signal.

[0139] In an embodiment, a system includes: a laser printer cartridge having an external body; and a toner level measurement circuit device coupled to the external body, wherein the toner level measurement circuit device, in operation, generates an acceleration signal indicative of vibrations associated with the laser printer cartridge; generates a charge change signal indicative of changes in electrostatic charge associated with the laser printer cartridge; generates a characteristic parameter based on the acceleration signal and the charge change signal; and generates a level signal indicative of a level of toner in the laser printer cartridge based on the generated characteristic parameter.

[0140] In an embodiment, a toner level measurement circuit device includes: an acceleration sensor that generates an acceleration signal during operation; a charge change sensor that generates a charge change signal during operation; and a processing circuit device coupled to the acceleration sensor and the charge change sensor, wherein the processing circuit device, during operation: generates a characteristic parameter based on the acceleration signal and the charge change signal; and generates a level signal indicating the level of the toner in the box based on the generated characteristic parameter.

[0141] In an embodiment, a laser printer cartridge includes: a toner reservoir housed in an outer body; and a rotating element housed in the outer body, the rotating element including: a developer roller; an OPC drum; a primary charge roller; or a combination thereof.

[0142] In an embodiment, an acceleration sensor is coupled to the external body adjacent to one of the rotating elements; and a charge change sensor is coupled to the external body adjacent to the toner sump.

[0143] In an embodiment, the system includes a laser printer comprising a laser printer cartridge and toner level measurement circuitry.

[0144] In an embodiment, a method includes generating an acceleration signal indicative of vibrations associated with a laser printer cartridge; generating a charge change signal indicative of changes in electrostatic charge associated with the laser printer cartridge; generating a characteristic parameter based on the acceleration signal and the charge change signal; and generating a level signal indicative of a level of toner in the laser printer cartridge based on the generated characteristic parameter.

[0145] In an embodiment, the method includes: generating an acceleration sensor using an acceleration sensor of a laser printer cartridge; generating a charge change signal using a charge change sensor of the laser printer cartridge; generating a characteristic parameter using a processing circuit device of the laser printer cartridge, the processing circuit device being coupled to the acceleration sensor and the charge change sensor; and generating a level signal using the processing circuit device.

[0146] In an embodiment, generating the level signal comprises selecting a value from a set of values ​​corresponding to defined levels of toner in the laser printer cartridge.

[0147] In an embodiment, generating the level signal comprises processing the feature parameters using a classifier. In an embodiment, the classifier is a decision tree classifier.

[0148] In an embodiment, generating characteristic parameters includes determining: the average value of the acceleration signal, the average value of the charge change signal, the variance of the acceleration signal, the variance of the charge change signal, the energy of the acceleration signal, the energy of the charge change signal, the zero crossing value of the acceleration signal, the zero crossing value of the charge change signal, the peak detector value of the acceleration signal, the peak detector value of the charge change signal, the peak-to-peak distance of the acceleration signal, the peak-to-peak distance of the charge change signal, the minimum value of the acceleration signal, the minimum value of the charge change signal, the maximum value of the acceleration signal, the maximum value of the charge change signal, or a combination thereof.

[0149] In an embodiment, the method comprises: generating a normalized acceleration signal; and generating a characteristic parameter based on the normalized acceleration signal.

[0150] In an embodiment, the method comprises: generating a filtered charge variation signal; and generating a characteristic parameter based on the filtered charge variation signal.

[0151] In an embodiment, generating the filtered charge variation signal includes bandpass filtering the charge variation signal.

[0152] In one embodiment, the contents of a non-transitory computer-readable medium configure a processing circuit device to perform a method comprising: generating an acceleration signal indicative of vibration associated with a laser printer cartridge; generating a charge change signal indicative of a change in electrostatic charge associated with the laser printer cartridge; generating a characteristic parameter based on the acceleration signal and the charge change signal; and generating a level signal indicative of a level of toner in the laser printer cartridge based on the generated characteristic parameter. In one embodiment, the contents include instructions executable by the processing circuit device. In one embodiment, the processing circuit device includes a classifier; and the contents configure the classifier to generate the level signal based on the characteristic parameter.

[0153] Some embodiments may take the form of or include a computer program product. For example, according to one embodiment, a computer readable medium is provided, comprising a computer program suitable for performing one or more of the methods or functions described above. The medium may be a physical storage medium (such as, for example, a read-only memory (ROM) chip), or a disk (such as a digital versatile disk (DVD-ROM), a compact disk (CD-ROM)), a hard disk, a memory, a network, or a portable medium article thereof to be read by an appropriate drive or via an appropriate connection, including encoding in one or more bar codes or other related codes stored on one or more such computer readable media and readable by an appropriate reader device.

[0154] In addition, in some embodiments, some or all of the methods and / or functions may be implemented or provided in other manners (such as at least partially in firmware and / or hardware), which firmware and / or hardware include but are not limited to one or more application-specific integrated circuits (ASICs), digital signal processors, discrete circuits, logic gates, standard integrated circuits, controllers (e.g., by executing appropriate instructions, and including microcontrollers and / or embedded controllers), field programmable gate arrays (FPGAs), complex programmable logic devices (CPLDs), etc., as well as devices using RFID technology and various combinations thereof.

[0155] The various embodiments described above can be combined to provide further embodiments. Aspects of the embodiments can be modified, if necessary, to employ concepts of the various patents, applications, and publications to provide other embodiments.

[0156] These and other changes can be made to the embodiments in light of the above detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and claims, but should be construed to encompass all possible embodiments within the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by this disclosure.

Claims

1. A device comprising: an acceleration sensor operable to generate an acceleration signal indicative of vibrations associated with a cartridge of the laser printer; a charge change sensor operable to generate a charge change signal indicative of a change in electrostatic charge associated with said cartridge of said laser printer; as well as Processing circuitry coupled to the acceleration sensor and the charge change sensor; wherein the processing circuitry, in operation: generating a characteristic parameter based on the acceleration signal and the charge change signal; as well as A level signal indicating the level of toner in the cartridge is generated based on the generated characteristic parameters including the peak-to-peak distance of the acceleration signal and the maximum value of the charge variation signal.

2. The apparatus of claim 1 , wherein the processing circuitry comprises: A feature extraction module generates the feature parameters during operation; as well as A classification module is coupled to the feature extraction module, wherein in operation, the classification module generates the level signal.

3. The apparatus of claim 1 , comprising an integrated circuit, the integrated circuit comprising: the processing circuit device; the processing circuit device and the acceleration sensor; said processing circuitry and said charge change sensor; or The processing circuit device, the acceleration sensor and the charge change sensor.

4. The apparatus according to claim 1, wherein The processing circuit arrangement is in operation, determining a norm of the acceleration signal to generate a normalized acceleration signal, and The characteristic parameter is generated based on the normalized acceleration signal.

5. The apparatus according to claim 1, wherein The charge change sensor includes a filter operable to filter the charge change signal to generate a filtered charge change signal, and The processing circuit device is operable to generate the characteristic parameter based on the filtered charge change signal. The apparatus of claim 5 , wherein the filter is a bandpass filter.

7. The apparatus according to claim 1, wherein The acceleration sensor includes a filter that is operable to filter the acceleration signal to generate a filtered acceleration signal, and The processing circuitry is operable to generate the characteristic parameter based on the filtered acceleration signal.

8. A system comprising: a laser printer case having an outer body; and a toner level measurement circuit arrangement coupled to the external body, wherein the toner level measurement circuit arrangement, in operation: generating an acceleration signal indicative of vibration associated with the laser printer cartridge; generating a charge change signal indicative of a change in electrostatic charge associated with the laser printer cartridge; generating a characteristic parameter based on the acceleration signal and the charge change signal; as well as A level signal indicative of a level of toner in the laser printer cartridge is generated based on the generated characteristic parameters, the generated characteristic parameters including a peak-to-peak distance of the acceleration signal and a maximum value of the charge variation signal.

9. The system of claim 8, wherein the toner level measurement circuitry comprises: an acceleration sensor, in operation, generating said acceleration signal; a charge change sensor, operable to generate said charge change signal; as well as Processing circuitry coupled to the acceleration sensor and the charge change sensor, wherein the processing circuitry, in operation: generating the characteristic parameter based on the acceleration signal and the charge change signal; and The level signal indicating the level of toner in the cartridge is generated based on the generated characteristic parameter.

10. The system of claim 9, wherein the laser printer cartridge comprises: a toner reservoir housed in the outer body; as well as a rotating element housed in the outer body, the rotating element comprising: developer roller; OPC drum; Primary charge roller; or A combination of the above.

11. The system according to claim 10, wherein: The acceleration sensor is coupled to the outer body adjacent to a rotating element of the rotating elements; and The charge change sensor is coupled to the outer body adjacent to the toner sump.

12. The system of claim 8, comprising a laser printer including the laser printer cartridge and the toner level measurement circuitry.

13. A method comprising: generating an acceleration signal indicative of vibration associated with the laser printer cartridge; generating a charge change signal indicative of a change in electrostatic charge associated with the laser printer cartridge; generating a characteristic parameter based on the acceleration signal and the charge change signal; as well as A level signal indicative of a level of toner in the laser printer cartridge is generated based on the generated characteristic parameters, the generated characteristic parameters including a peak-to-peak distance of the acceleration signal and a maximum value of the charge variation signal.

14. The method according to claim 13, comprising: generating said acceleration sensor using an acceleration sensor of said laser printer cartridge; generating the charge change signal using a charge change sensor of the laser printer cartridge; generating the characteristic parameter using processing circuitry of the laser printer cartridge, the processing circuitry coupled to the acceleration sensor and the charge change sensor; as well as The horizontal signal is generated using the processing circuitry.

15. The method of claim 13, wherein generating the level signal comprises selecting a value from a set of values ​​corresponding to defined levels of toner in the laser printer cartridge. The method of claim 15 , wherein generating the level signal comprises processing the feature parameters using a classifier. The method of claim 16 , wherein the classifier is a decision tree classifier.

18. The method of claim 13, wherein generating the characteristic parameters comprises determining: The average value of the acceleration signal, The average value of the charge change signal, The variance of the acceleration signal, The variance of the charge change signal, The energy of the acceleration signal, The energy of the charge change signal, The zero-crossing value of the acceleration signal, the zero-crossing value of the charge change signal, the peak detector value of the acceleration signal, the peak detector value of the charge change signal, the peak-to-peak distance of the charge change signal, The minimum value of the acceleration signal, the minimum value of the charge change signal, The maximum value of the acceleration signal, or A combination of the above.

19. The method according to claim 13, comprising: generating a normalized acceleration signal; as well as A characteristic parameter is generated based on the normalized acceleration signal.

20. The method of claim 13, comprising: generating a filtered charge change signal; as well as A characteristic parameter is generated based on the filtered charge change signal.

21. The method according to claim 20, wherein Generating the filtered charge variation signal includes bandpass filtering the charge variation signal.

22. The method according to claim 17, wherein the plurality of defined levels of the toner in the cartridge include a first level to a fifth level, the first level being greater than the second level, the second level being greater than the third level, the third level being greater than the fourth level, and the fourth level being greater than the fifth level, Generating the horizontal signal includes: Checking whether the peak-to-peak distance satisfies a first condition, and if the peak-to-peak distance is less than or equal to a first threshold distance, the first condition is satisfied; If the first condition is satisfied, checking whether the peak-to-peak distance satisfies a second condition, and if the peak-to-peak distance is less than or equal to a second threshold distance, then the second condition is satisfied; If the second condition is satisfied, determining that the horizontal signal corresponds to the first level; If the second condition is not met, checking whether the maximum value meets a third condition, and if the maximum value is less than or equal to the first threshold maximum value, the third condition is met; If the third condition is not satisfied, determining that the horizontal signal corresponds to the third level; If the third condition is satisfied, checking whether the peak-to-peak distance satisfies a fourth condition, and if the peak-to-peak distance is less than or equal to a third threshold distance, then the fourth condition is satisfied; If the fourth condition is satisfied, determining that the horizontal signal corresponds to the third level; If the fourth condition is not satisfied, determining that the horizontal signal corresponds to the second level; If the first condition is not met, checking whether the peak-to-peak distance meets a fifth condition, and if the peak-to-peak distance is less than or equal to a fourth threshold distance, then the fifth condition is met; If the fifth condition is satisfied, determining that the horizontal signal corresponds to the fourth level; and If the fifth condition is not satisfied, determining that the horizontal signal corresponds to the fifth level, and The second threshold distance (A2) is smaller than the third threshold distance (A3), the third threshold distance is smaller than the first threshold distance (A1), and the first threshold distance is smaller than the fourth threshold distance (A4).

23. The method of claim 22, wherein: The first threshold distance (A1) is equal to 0.306±0.001 mg; The second threshold distance (A2) is equal to 0.141±0.001 mg; The first threshold maximum value (C1) is equal to 1.463±0.001LSB; The third threshold distance (A3) is equal to 0.193±0.001 mg; and The fourth threshold distance (A4) is equal to 0.460±0.001 mg.

24. A non-transitory computer-readable medium having content, the content configuring a processing circuit device to perform a method comprising: generating an acceleration signal indicative of vibration associated with the laser printer cartridge; generating a charge change signal indicative of a change in electrostatic charge associated with the laser printer cartridge; generating a characteristic parameter based on the acceleration signal and the charge change signal; as well as A level signal indicative of a level of toner in the laser printer cartridge is generated based on the generated characteristic parameters, the generated characteristic parameters including a peak-to-peak distance of the acceleration signal and a maximum value of the charge variation signal.

25. The non-transitory computer-readable medium of claim 24, wherein the content comprises instructions executable by the processing circuitry.

26. The non-transitory computer readable medium of claim 24, wherein: The processing circuitry includes a classifier; and The content configures the classifier to generate a level signal based on the feature parameter.

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