Printer media low sensing using motor current consumed while feeding

Abstract

Printer circuits and components for detecting a low media condition of a printer are provided. A printer circuit includes a motor coupled to a platen roller; a current sense resistor coupled in series with the motor; a current measurement circuit including an operational amplifier circuit configured to receive an input voltage and an output voltage of the current sense resistor, generate a differential voltage based at least in part on the input voltage and the output voltage, and convert the differential voltage to a current; and an analog-to-digital converter and control mechanism configured to receive the current from the current measurement circuit and control operation of the motor based at least in part on the current.

Description

Technical Field

[0001] Exemplary embodiments of this disclosure relate generally to printers, and more particularly to printers with improved media low detection. Background Technology

[0002] Printers typically include components such as a printhead, a printing platen, a paper supply, and a control mechanism. The control mechanism controls the movement of the printhead relative to the paper supply, selects the characters to be printed, and advances the printing media (e.g., paper) as needed.

[0003] Printers are generally not expected to run without paper. For example, a thermal printer running without paper may overheat because the paper is also used to absorb the heat generated by the printhead during printing. Furthermore, running a thermal printer without paper can cause excessive wear on the printhead, as the printhead will be running directly on the printing platen instead of on the printing media. Low media detection can also serve as an indication to prepare or purchase a replacement roll of printing media before it runs out.

[0004] Therefore, to avoid printers running out of paper, conventional printers are equipped with low paper sensing and warning systems. These systems provide notification that the paper supply is about to run out. However, such systems can come at the cost of additional hardware and design footprint. Therefore, a media low detection feature is needed for space-constrained desktop printers. Summary of the Invention

[0005] The various implementation schemes described herein relate to circuits, apparatus, and methods for detecting low media conditions in printer equipment.

[0006] According to various embodiments of this disclosure, a printer circuit is provided. In some embodiments, the printer circuit includes a motor coupled to a table roller; a current-sensing resistor coupled in series with the motor; a current-measuring circuit including an operational amplifier circuit configured to receive an input voltage and an output voltage of the current-sensing resistor, generate a differential voltage based at least in part on the input voltage and the output voltage, and convert the differential voltage into a current; and an analog-to-digital converter and a control mechanism configured to receive a current from the current-measuring circuit and control the operation of the motor based at least in part on the current.

[0007] In some embodiments, the current corresponds to the amount of current consumed by the motor. In some embodiments, the motor drives the platen rollers to draw printing media from the media supply source. In some embodiments, the current is proportional to the amount of torque required for the platen rollers to draw printing media from the media supply source to achieve a given printing speed. In some embodiments, the current is directly proportional to the amount of remaining printing media in the media supply source. In some embodiments, the current measurement circuit is coupled in parallel with a current sensing resistor.

[0008] According to another embodiment, a printer apparatus is provided. In some embodiments, the printer apparatus includes a media supply source including printing media; a motor coupled to a platen roller configured to draw printing media from the media supply source; a current measurement circuit; a memory device having executable instructions stored therein; and a processor, in response to the executable instructions, configured to receive a signal from the current measurement circuit, determine based on the signal the current consumed by the motor, determine that the consumed current is less than a given threshold, and generate a low media message.

[0009] In some embodiments, the signal includes a differential voltage between the input voltage and the output voltage from the current-sensing resistor. In some embodiments, the current consumed depends on the amount of printing media drawn by the motor from the media supply source and the amount of current required to operate at a predetermined operating speed. In some embodiments, a given threshold includes a current value indicating a low media supply. In some embodiments, the current value corresponds to the current consumed by the motor operating at low torque during a low media supply period. In some embodiments, the printer apparatus also includes a display screen configured to display a media low message. In some embodiments, the processor is also configured to send a media low message to a controller for toggling at least one of an indicator light and a speaker.

[0010] According to another embodiment, a method for detecting a low media condition in a printer is provided. The printer includes a media supply source including printing media; a motor coupled to a platen roller configured to draw printing media from the media supply source; and current measurement circuitry. In some embodiments, the method includes receiving a signal from the current measurement circuitry via a processor; determining, based on the signal, a current consumed by the motor; determining, via the processor, that the consumed current is less than a given threshold; and generating a low media message via the processor.

[0011] In some embodiments, the signal includes a differential voltage between the input voltage and the output voltage from the current-sensing resistor. In some embodiments, the current consumed depends on the amount of printing media drawn by the motor from the media supply source and the amount of current required to operate at a predetermined operating speed. In some embodiments, a given threshold includes a current value indicating a low media supply. In some embodiments, the current value corresponds to the current consumed by the motor operating at low torque during a low media supply period. In some embodiments, the printer device also includes a display screen configured to display a media low message. In some embodiments, the processor is also configured to send a media low message to a controller for toggling at least one of an indicator light and a speaker.

[0012] The foregoing illustrative description of the invention, as well as other exemplary objects and / or advantages of this disclosure, and the ways in which these objects and / or advantages are achieved, are further explained in the following detailed description and accompanying drawings. Attached Figure Description

[0013] The description of the exemplary embodiments can be read in conjunction with the accompanying drawings. It will be understood that, for simplicity and clarity of illustration, the elements shown in the figures are not necessarily drawn to scale unless otherwise described. For example, unless otherwise described, the dimensions of some elements may be exaggerated relative to others. Embodiments incorporating the teachings of this disclosure are shown and described with respect to the accompanying drawings presented herein, in which:

[0014] Figure 1 A cross-sectional view of an exemplary printer filled with media is shown.

[0015] Figure 2 A cross-sectional view of an exemplary printer carrying a small amount of media is shown.

[0016] Figure 3 Circuit diagrams of various embodiments according to this disclosure are shown.

[0017] Figure 4 An exemplary flowchart illustrating an exemplary method for detecting a low media state of a printer according to various embodiments of the present disclosure is shown. Detailed Implementation

[0018] Some embodiments of this disclosure will be described more fully below with reference to the accompanying drawings, which illustrate some, but not all, embodiments of this disclosure. In fact, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to enable this disclosure to meet applicable legal requirements. Throughout this document, similar reference numerals refer to similar elements.

[0019] As used herein, terms such as “front,” “rear,” “top,” etc., in the examples provided below, are used for illustrative purposes to describe the relative positions of certain parts or portions of parts. Additionally, as will be apparent to those skilled in the art based on this disclosure, the terms “substantially” and “approximately” indicate that the referenced element or associated description is accurate within applicable engineering tolerances.

[0020] As used herein, the term “comprising” means including but not limited to, and should be interpreted in the manner commonly used in the patent context. It should be understood that the use of broad terms such as “comprising,” “including,” and “having” provides support for narrower terms such as “consisting of,” “substantially composed of,” and “substantially constituted by.”

[0021] The phrases “in one embodiment”, “according to one embodiment”, etc., generally mean that the specific feature, structure or characteristic following the phrase can be included in at least one embodiment of the present disclosure, and can be included in more than one embodiment of the present disclosure (importantly, such phrases do not necessarily refer to the same embodiment).

[0022] The terms “example” or “exemplary” are used herein to mean “serving as an example, instance, or illustration.” Any specific implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other specific implementations.

[0023] If the specification states that a component or feature "may," "can," "should," "will," "preferably," "possibly," "usually," "optionally," "for example," "often," or "may" (or other such language) be included or have that characteristic, then the specific component or feature is not necessarily included or has that characteristic. Such components or features may be optionally included in some embodiments or excluded.

[0024] Various exemplary embodiments of this disclosure overcome the technical challenges and difficulties in providing low print media supply detection for printers using low footprint hardware designs. According to various examples of this disclosure, components of exemplary hardware for low print media supply sources are disclosed.

[0025] Figure 1A printer 100 is presented, which includes a media supply source 104, a thermal printhead 106, a platen roller 108, and a base 110. The media supply source 104 may include printing media, such as a roll of paper including a core and a sheet of paper of a certain length surrounding the core. During operation of the printer 100, the media supply source 104 may be reduced from a full load of media 102A as the paper supply source roller rotates, and feed through the thermal printhead 106 and the platen roller 108, such that the media supply source 104 is reduced to a smaller amount of media 102B, such as... Figure 2 As shown in the diagram. Printer 100 may be configured such that the base 110 of printer 100 is placed on a mounting surface. In some embodiments, the mounting surface may be, for example, a table or workbench, such that the orientation of printer 100 is generally horizontal.

[0026] The ink medium 112, along with the printing medium from the media supply source 104, can be fed together between the thermal printhead 106 and the platen roller 108. The thermal printhead 106 may include a plurality of resistive elements that can be selectively energized to record data in the form of hard copies. The resistive elements can receive energy from the power source in response to stored or programmed digital information associated with text, barcodes, pictures, or graphic images. As the printing medium from the media supply source 104 passes between the thermal printhead 106 and the platen roller 108, heat from each energized element can be applied to the ink medium 112 to transfer ink or dye to the printing medium from the media supply source 104.

[0027] The platen roller 108 may include a rigid shaft, typically metal, and an elastomeric layer surrounding the shaft. The platen roller 108 may be driven by a motor that draws printing media from the media supply source 104 when the thermal printhead 106 prints on printing media from the media supply source 104. When the media supply source 104 includes a full load of media 102A, the motor may require a larger drive current to draw printing media from the media supply source 104 compared to the current required when the media supply source 104 includes a smaller amount of media 102.

[0028] According to various embodiments of this disclosure, a current sensing circuit may be configured within a printer (such as printer 100) to determine the drive current of the motor driving the table roller 108. Based on the value of the drive current, the amount of remaining print media can be determined.

[0029] Figure 3Exemplary printer circuitry according to some embodiments of this disclosure is presented. Printer circuitry 300 includes a bridging circuitry 302, a current measurement circuitry 310, an analog-to-digital converter, and a control mechanism 312. Bridging circuitry 302 includes a motor 304 and a current sensing resistor 306. Bridging circuitry 302 allows measurement of an unknown current value corresponding to the current consumed by motor 304. Motor 304 may be coupled to, for example, a platen roller 108. The amount of current consumed by motor 304 is proportional to the amount of torque required for platen roller 108 to draw printing media from media supply source 104 to achieve a given printing speed. As discussed above, when media supply source 104 includes a full load of media 102A, the motor may require a larger drive current to draw printing media from media supply source 104 compared to the current required when media supply source 104 includes less media 102. Therefore, the current consumed by motor 304 is directly proportional to the amount of remaining printing media in media supply source 104. In some implementations, the motor can be configured to run the printer at different printing speeds (such as 2 ips (inches per second) to 12 ips, etc.), and for each speed setting, the torque and current required to run the motor to maintain the speed may differ.

[0030] A current-sensing resistor 306 is configured to be coupled in series with a motor 304. According to Kirchhoff's current law, the current across the current-sensing resistor 306 is equal to the current consumed by the motor 304. Therefore, the measured current of the current-sensing resistor 306 can provide the current consumed by the motor 304. A current measurement circuit 310 is coupled in parallel with the current-sensing resistor 306 and receives the input voltage and output voltage of the current-sensing resistor 306 as inputs. According to various embodiments of this disclosure, the current measurement circuit 310 may include an operational amplifier circuit. The current measurement circuit 310 can generate a differential voltage based on the input voltage and the output voltage.

[0031] The current sensing resistor 306 may include a resistor with a known resistance value. According to various embodiments of this disclosure, the current sensing resistor 306 may include a minimum resistance value that reduces the load and consumed current, which could otherwise adversely affect the current flowing to the motor 304 and the performance of the motor 304. The minimum value of the current sensing resistor 306 may produce a proportional minimum voltage value. For compensation, the current measurement circuit 310 may amplify the smaller voltage (e.g., via an operational amplifier) ​​for upstream conversion by the analog-to-digital converter (312). The current measurement circuit 310 may amplify the input and output voltages of the current sensing resistor 306 to a level usable by the analog-to-digital converter and the control mechanism 312. In some embodiments, the current measurement circuit 310 may include an optically isolated amplifier to provide electrical isolation.

[0032] In some implementations, the current measurement circuit 310 may include a differential voltage-to-current converter. Therefore, the analog-to-digital converter and control mechanism 312 may receive an analog signal from the current measurement circuit 310 and convert that analog signal into a digital signal representing the current consumed by the motor 304 during operation.

[0033] In some embodiments, receiving signals from the current measurement circuitry 310 via the analog-to-digital converter and control mechanism 312 may include reading signals via printer firmware executed by a programmable processor during operation. The printer firmware may monitor the current consumed by the motor associated with the table roller 108 and generate a low media warning or message when the current falls below a predetermined threshold. The programmable processor may be implemented as, for example, various devices, including one or more microprocessors accompanied by a digital signal processor; one or more processors without an accompanying digital signal processor; one or more coprocessors; one or more multi-core processors; one or more controllers; processing circuitry; one or more computers; and various other processing elements (including integrated circuits, such as ASICs or FPGAs, or some combination thereof). In some embodiments, the programmable processor may include one or more processors.

[0034] See now Figure 4 An exemplary flowchart is provided, illustrating an exemplary method for detecting a low media state of a printer according to some exemplary embodiments of the present disclosure. It should be noted that each block in the flowchart, and combinations of blocks in the flowchart, can be implemented by various components such as hardware, firmware, circuit systems, and / or other devices associated with the execution of software including one or more computer program instructions. For example, Figure 4 One or more steps / operations described herein may be embodied by computer program instructions, which may be stored in the non-transitory memory of an apparatus employing embodiments of the present disclosure and executed by processor components in the apparatus (such as, but not limited to, monitoring systems, client computing devices, remote computing servers, etc.). For example, these computer program instructions may instruct processor components to function in a particular manner, causing the instructions stored in computer-readable storage to produce an article of art whose execution implements the function specified in the flowchart block.

[0035] As described above and as will be understood based on this disclosure, embodiments of this disclosure may include various components, including entirely hardware or any combination of software and hardware. Furthermore, embodiments may take the form of a computer program product on at least one non-transitory computer-readable storage medium having computer-readable program instructions (e.g., computer software) embodied in the storage medium. Similarly, embodiments may take the form of computer program code stored on at least one non-transitory computer-readable storage medium. Any suitable computer-readable storage medium may be utilized, including non-transitory hard disks, CD-ROMs, flash memory, optical storage devices, or magnetic storage devices.

[0036] See now Figure 4 The illustration shows an example method 400 for detecting a low media state in a printer according to some exemplary embodiments described herein. In step 402, a programmable processor receives a signal from a current measurement circuit within the printer's circuitry. The motor may include a motor for drawing printing media from a media supply source via a platen roller. As discussed above, the signal can be converted based on the differential voltage between the input and output voltages of a current-sensing resistor in the printer's circuitry. The current-sensing resistor may include a resistor for measuring the current consumed by the motor within the printer's circuitry.

[0037] In some implementations, after step 402, the exemplary method proceeds to step 404, where the programmable processor determines the current consumed by the motor based on the signal. The current consumed by the motor may vary throughout the printer's operation. For example, as the printer's media supply decreases, the amount of current required for the motor to draw printing media (e.g., torque) from the media supply source and operate at a predetermined operating speed may decrease. Conversely, replenishing the media supply source may require the motor to draw more current to draw printing media from the media supply source and operate at a predetermined operating speed.

[0038] In some embodiments, after step 404, the exemplary method proceeds to step 406, where the programmable processor determines whether the current consumed is less than a given threshold. The given threshold may include a current value indicating a low media supply. For example, when the media supply is low, the current value may correspond to the current consumed by the motor operating at low torque. In some embodiments, the motor may be configured to operate the printer at different printing speeds (such as 2 ips (inches per second) to 12 ips, etc.), and for each speed setting, the torque required to maintain the speed may be different. Therefore, the given threshold may be determined at least in part based on the current consumed to operate the printer at a given printing speed. If the current consumed is not less than the given threshold, the exemplary method proceeds to step 402 to receive another signal.

[0039] In some embodiments, after step 406, if the current consumed is less than a given threshold, the exemplary method proceeds to step 408, in which the programmable processor generates a media low message. For example, the media low message may be displayed on the printer's screen. In some embodiments, the media low message may be sent by the programmable processor to a controller for toggling indicator lights such as lamps and / or for issuing a warning on the printer.

[0040] It should be understood that this disclosure is not limited to the specific embodiments disclosed, and modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terminology is used herein, it is used in a general and descriptive sense only, and not for purposes of limitation, unless otherwise stated.

Claims

1. A printer circuit, the printer circuit comprising: An electric motor coupled to a table roller; A current sensing resistor, which is coupled in series with the motor; A current measurement circuit, comprising an operational amplifier circuit configured to receive an input voltage and an output voltage of the current sensing resistor, generate a differential voltage based at least in part on the input voltage and the output voltage, and convert the differential voltage into a current; and An analog-to-digital converter and control mechanism are configured to receive the current from the current measurement circuit and to control the operation of the motor at least in part based on the current.

2. The printer circuit according to claim 1, wherein, The current corresponds to the amount of current consumed by the motor.

3. The printer circuit according to claim 1, wherein, The motor drives the platen roller to extract printing media from the media supply source.

4. The printer circuit according to claim 1, wherein, The current is proportional to the amount of torque required for the platen roller to draw printing media from the media supply source to achieve a given printing speed.

5. The printer circuit according to claim 1, wherein, The current is directly proportional to the amount of remaining printing media in the media supply source.

6. The printer circuit according to claim 1, wherein, The current measurement circuit is coupled in parallel with the current sensing resistor.

7. A printer apparatus, the printer apparatus comprising: A media supply source, wherein the media supply source includes printing media; A motor coupled to a platen roller configured to draw printing media from the media supply source; Current measurement circuit; A memory device having executable instructions stored therein; and The processor, in response to the executable instructions, is configured to: Receive signals from the current measurement circuit; The current consumed by the motor is determined based on the signal; Determine that the current consumed is less than a given threshold; as well as Generate low-frequency messages.

8. The printer apparatus according to claim 7, wherein, The signal includes the differential voltage between the input voltage and the output voltage from the current sensing resistor.

9. The printer apparatus according to claim 7, wherein, The current consumed depends on the amount of printing media drawn from the media supply source by the motor and the amount of current required to operate at a predetermined operating speed.

10. The printer apparatus according to claim 7, wherein, The given threshold includes a current value indicating a low dielectric supply.

11. The printer apparatus according to claim 10, wherein, The current value corresponds to the current consumed by the motor when it operates at low torque during periods of low medium supply.

12. The printer apparatus of claim 7, further comprising a display screen configured to display the media low message.

13. The printer apparatus according to claim 7, wherein, The processor is further configured to send the medium low message to the controller to switch at least one of the indicator light and the speaker.

14. A method for detecting a low media condition in a printer, the printer comprising a media supply source including printing media; a motor coupled to a platen roller configured to draw the printing media from the media supply source; And a current measurement circuit, the method includes: The processor receives signals from the current measurement circuit. The processor determines the current consumed by the motor based on the signal; The processor determines that the current consumption is less than a given threshold; and The processor generates a medium low message.

15. The method according to claim 14, wherein, The signal includes the differential voltage between the input voltage and the output voltage from the current sensing resistor.

16. The method of claim 14, wherein, The current consumption depends on the amount of printing media drawn from the media supply source by the motor and the amount of current required to operate at a predetermined operating speed.

17. The method of claim 14, wherein, The given threshold includes a current value indicating a low dielectric supply.

18. The method according to claim 17, wherein, The current value corresponds to the current consumed by the motor when it operates at low torque during periods of low medium supply.

19. The method of claim 14, wherein, The printer device also includes a display screen configured to display the media low message.

20. The method of claim 14, wherein, The processor is further configured to send the medium low message to the controller to switch at least one of the indicator light and the speaker.

Images