Patent Application
20060012819
Imaging devices are generally powered by a conventional alternating current (AC) external power source (i.e., 100-120 volts or, for some countries, 200-240 volts). Recently, a data interface bus (e.g., a universal serial bus (USB)) has become a widely used medium for providing power to various types of imaging devices, thereby enabling the device to obtain power from another electronic device (e.g., a desktop or notebook computer) and alleviating a need for a separate conventional AC power source or outlet. However, because of the generally low power level available via a data interface bus (e.g., approximately 2 watts), scanning operations performed by the imaging device using power supplied by a data interface bus are generally very slow.
In accordance with one embodiment of the present invention, an imaging device power management system comprises a control circuit adapted to vary a duty cycle of a scanning module of an imaging device during a scanning operation performed by the scanning module based on a source of energy coupled to the imaging device for operating the scanning module.
In accordance with another embodiment of the present invention, an imaging device power management method comprises varying a duty cycle of a scanning module of an imaging device during a scanning operation performed by the scanning module based on the type of energy source coupled to the imaging device for performing the scanning operation.
In accordance with another embodiment of the present invention, an imaging device power management system comprises a light source adapted to illuminate an object during a scanning operation and a storage device adapted to store energy received from a data interface bus. The system also comprises a control circuit adapted to vary a duty cycle of the light source during the scanning operation corresponding to the energy stored in the storage device.
For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following descriptions taken in connection with the accompanying drawings in which:
The preferred embodiments of the present invention and the advantages thereof are best understood by referring to
Imaging device 12 may comprise any type of device for capturing or otherwise generating a scanned image of an object such as, but not limited to, a scanner, facsimile machine, or copier. Briefly, system 10 enables operation of imaging device 12 using any one of a plurality of different types of energy sources and, depending on the type of energy source providing power for operating imaging device 12, imaging device 12 is configured to variably control a duty cycle of imaging device 12 components to efficiently manage power consumption by imaging device 12 and enable operation of imaging device 12 with a reduced scanning time based on the type of power supply providing power to scanning device 12 for the scanning operation.
In the embodiment illustrated in
In operation, ASIC 22 monitors voltage levels of circuit 20, such as VI, VW, VC, and VR, to determine and control a duty cycle for operating scanning module 30 during a scanning operation. For example, if inputs to ASIC 22 indicate that energy is being received by imaging device 12 by external energy source 16, for example, based on a voltage measurement of VW, ASIC 22 is configured to operate scanning module 30 at a particular duty cycle, for example, a 100% duty cycle. However, if imaging device 12 is receiving a reduced level of power or energy, for example, from data interface bus energy source 18, ASIC 22 is configured to vary a duty cycle for operating scanning module 30 during a scanning operation. For example, in operation, when energy is received via data interface bus energy source 18, energy is stored by storage device 60 such that energy from storage device 60 is used to operate scanning module 30 during a scanning operation. If the energy level of storage device 60 is equal to or decreases to a value within a predetermined threshold or range of VR, ASIC 22 pauses the scanning operation, for example, by turning off light source 40 and suspending movement of scanning module 30, to enable or otherwise facilitate recharging of storage device 60. In response to the energy level stored in storage device 60 increasing to a predetermined value or threshold, ASIC 22 resumes the scanning operation by turning on light source 40 and resuming movement of scanning module 30. Thus, for example, when VC is equal to or greater than VR plus a predetermined voltage measurement or threshold, ASIC 22 is configured to resume operation of scanning module 30. Additionally, as described above, if power or energy is available via external energy source 16, VC will be greater than VR, thereby enabling operation of scanning module 30 at a 100% duty cycle. Logic rules for operating scanning module 30 at a variable duty cycle may be expressed by the following: when VC=VR (or VR+C), where C represents a predetermined or threshold voltage level, ASIC 22 is configured to turn off light source 40 and pause or suspend movement of scanning module 30; and when VC=VI+C, ASIC 22 is configured to turn on light source 40 and resume the scanning operation. Thus, ASIC 22 is configured to automatically vary a duty cycle of scanning module 30 (e.g., by varying a duty cycle of light source 40) based the type of energy source providing energy to imaging device 12 and/or stored energy level within storage device 60.
At block 112, ASIC 22 monitors a stored energy level of storage device 60. At decisional block 114, a determination is made whether the energy storage level within storage device 60 has decreased or fallen below a predetermined threshold. If the stored energy level within the storage device 60 has not decreased or fallen below a predetermined threshold, the method proceeds to decisional block 116, where a determination is made whether the scanning operation is complete. If the scanning operation is not yet complete, the method proceeds to block 108, where the scanning operation continues. If the scanning operation is complete, the method ends.
If at decisional block 114 it is determined that the energy level stored within storage device 60 has decreased or fallen below a predetermined threshold, the method proceeds to block 118, where ASIC 22 suspends movement of scanning module 30 and turns off light source 40. At block 120, ASIC 22 pauses the scanning operation to enable recharging of storage device 60. The method then proceeds to block 102, where ASIC 22 monitors or otherwise determines the energy level stored by storage device 60.
Thus, embodiments of the present invention enable operation of imaging device 12 at a variable duty cycle based on a source of energy supplying power to the imaging device. Thus, for example, when energy is being supplied to imaging device via a data interface bus, the duty cycle of scanning module 30 is variably controlled to facilitate efficient operation of imaging device 12 and, if power is available from another energy source capable of providing a greater energy level than the data interface bus, the duty cycle is variably controlled to reduce the time necessary for completing the scanning operation.
