Abstract:
An improved apparatus and method for reducing printer power consumption, thereby conserving energy and reducing heat generation. A power control circuit automatically transitions a printer from a standby mode to an OFF state when the computer it is attached to is powered down or transitions to an inactive state. In various embodiments of the invention printer power consumption is reduced with corresponding decreases in heat generation, which can extend the life of printer components and increase their reliability, reduce the need for repairs, and prolong effective printer life.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates in general to the field of information system management and more specifically, to printer power consumption management.  
         [0003]     2. Description of the Related Art  
         [0004]     As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.  
         [0005]     The number of information handling systems configured for the consumer market has continued to grow over the past several years. Many of these systems are used in conjunction with printers that are often left in a continuous ON state, needlessly consuming power even when the computer systems they are attached to are powered down. Current approaches to reducing printer power consumption consist of transitioning the printer to various standby modes after a predetermined period of inactivity. The length of time before the printer transitions to a standby mode may be contingent upon multiple factors, such as the printer&#39;s power consumption when it is in an active mode or its rated print speed (e.g., pages per minute).  
         [0006]     When a printer is in a standby mode, it is generally able to conserve energy yet transition to an active state more quickly than if it had been powered down completely. Regardless, while a printer may consume less power in a standby mode, it continues to be in a powered ON state, resulting in wasted energy. Furthermore, since the printer&#39;s components are still subjected to electrical power and resulting heat dissipation, their reliability and lifetime can be compromised, potentially shortening the effective lifetime of the printer. In view of the foregoing, there is a need for a system and method for transitioning a printer from a low-power standby mode to an OFF state when the computer it is attached to is powered down.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention provides an improved apparatus and method for printer power management. Various embodiments of the invention reduce printer power consumption, thereby conserving energy and reducing heat generation. Decreases in heat generation can extend the life of printer components and increase their reliability, which in turn can reduce the need for repairs and prolong effective printer life.  
         [0008]     The present invention allows increased power savings to be realized by automatically transitioning the printer from a low-power standby mode to an OFF state when the computer system it is attached to is powered down. In various embodiments of the invention, a power control circuit is internally implemented on a printer. In an alternate embodiment of the invention, the power control circuit is implemented on a Universal Serial Bus (USB) printer cable without changing the cable&#39;s form factor. Those of skill in the art will be aware that USB signals are transmitted on a twisted pair of data cables, labeled D+ and D−. The USB cable also provides a single +5V conductor to power connected USB devices. In an embodiment of the invention, as long as the information handling system controlling the printer is in an ON state, pin  1  of the USB connector will supply +5VDC to the printer. In the case of a dual port USB connector, pins  1  and  6  are +5VDC pins and will operate in a similar manner.  
         [0009]     When the internal power control circuit receives a logic high (i.e., +5V) signal from the USB connector, it will conduct the signal and maintain the printer&#39;s current power state. When the computer is turned OFF or transitions to an inactive state, pin  1  of the USB connector goes to a logic low (i.e., 1V) signal which causes the power control circuit to transition to an OFF state, which in turn transitions the printer to an OFF power state. In various embodiments of the invention, the manual power switch of the printer overrides the power control circuit of the invention, requiring no change in normal user operation.  
         [0010]     Those of skill in the art will understand that many such embodiments and variations of the invention are possible, including but not limited to those described hereinabove, which are by no means all inclusive. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     The present invention may be better understood, and its numerous objects, features and advantages made apparent to those skilled in the art by referencing the accompanying drawings. The use of the same reference number throughout the several figures designates a like or similar element.  
         [0012]      FIG. 1   a  is a generalized illustration of an information handling system that can be used to implement the method and apparatus of the present invention where a power control circuit is implemented on a printer;  
         [0013]      FIG. 1   b  is a generalized illustration of an information handling system that can be used to implement the method and apparatus of the present invention where a power control circuit is implemented on a USB cable without change to the form factor;  
         [0014]      FIG. 2   a  is a generalized block diagram of a USB cable as typically implemented to couple a printer and a host computer;  
         [0015]      FIG. 2   b  is a generalized block diagram of an embodiment of the invention as implemented on a printer to manage power consumption; and  
         [0016]      FIG. 2   c  is a generalized block diagram of an embodiment of the invention as implemented on a USB cable to manage power consumption of a printer; and  
         [0017]      FIG. 3  is a generalized schematic diagram of one embodiment of the present invention as implemented on a USB cable. 
     
    
     DETAILED DESCRIPTION  
       [0018]     Information handling system power control circuit automatically transitions printer from a standby mode to an OFF state when the computer it is attached to is powered down or transitions to an inactive state. For purposes of this disclosure, an information handling system may include any instrumentality or aggregate of instrumentalities operable to compute, classify, process, transmit, receive, retrieve, originate, switch, store, display, manifest, detect, record, reproduce, handle, or utilize any form of information, intelligence, or data for business, scientific, control, or other purposes. For example, an information handling system may be a personal computer, a network storage device, or any other suitable device and may vary in size, shape, performance, functionality, and price. The information handling system may include random access memory (RAM), one or more processing resources such as a central processing unit (CPU) or hardware or software control logic, ROM, and/or other types of nonvolatile memory. Additional components of the information handling system may include one or more disk drives, one or more network ports for communicating with external devices as well as various input and output (I/O) devices, such as a keyboard, a mouse, and a video display. The information handling system may also include one or more buses operable to transmit communications between the various hardware components.  
         [0019]     Printers that are typically used with information handling systems in a consumer operating environment are often left in a continuous ON state, even when the computer systems they are attached to are powered down. Even if a computer has a usage profile of 12 hours per day, the printer attached to it will often be in either an ON or low-power state for 24 hours per day. The present invention allows increased power savings to be realized by automatically transitioning the printer from a low-power standby mode to an OFF state when the computer system it is attached to is powered down. For example, by implementing the present invention, energy cost savings for a color printer that is capable of printing twenty pages per minute can be calculated as follows. Assuming a rate of $0.08 per Kilowatt hour a usage profile of 12 hours per day, and 70 watts of power consumption in standby mode, the standby mode power cost using current approaches would equate to:
 
0.070 KW×30 days×12 hours/day×$0.08 per KW hour=$2.016 per month.
 
 This would translate to approximately $24.00 in one year, $73 in 3 years, and $120 in 5 years. 
 
         [0020]     Referring now to  FIG. 1   a , a block diagram depicts an information handling system  100  that can be used to implement the method and apparatus of the present invention. The functional components of the information handling system include a processor (e.g., central processor unit or “CPU”)  102 , input/output (I/O) device interface  104 , such as a display, a keyboard, a mouse, a printer, and associated controllers, a hard drive or disk storage  106 , various other subsystems  108 , network port  110 , and system memory  112 . Data is transferred between the various system components via various data buses illustrated generally by bus  114 . Printer cable  116  couples I/O device interface  104  to printer  120 , which comprises power control circuit  118  as described in greater detail below.  
         [0021]     Referring now to  FIG. 1   b , a block diagram depicts an information handling system  100  that can be used to implement the method and apparatus of the present invention. The functional components of the information handling system include a processor (e.g., central processor unit or “CPU”)  102 , input/output (I/O) device interface  104 , such as a display, a keyboard, a mouse, a printer, and associated controllers, a hard drive or disk storage  106 , various other subsystems  108 , network port  110 , and system memory  112 . Data is transferred between the various system components via various data buses illustrated generally by bus  114 . Printer cable  116  comprises power control circuit  118 , which couples I/O device interface  104  to printer  120  as described in greater detail below.  
         [0022]      FIG. 2   a  is a generalized block diagram of a USB cable  116  as typically implemented to couple a printer  120  to host computer device interface  104 , which in turn is coupled to information handling system  100 . As will be understood by skilled practitioners of the art, USB printer cable  116  is typically comprised of conductor  202 , which carries a nominal V BUS  voltage of 5V via pin  1  of a USB cable, conductor  204 , which carries D+ data signals via pin  2  of a USB cable, conductor  206 , which carries D− data signals via pin  3  of a USB cable, and conductor  208 , which provides a ground on pin  4  of a USB cable.  
         [0023]      FIG. 2   b  is generalized block diagram of an embodiment of the invention wherein power control circuit  118  is implemented on printer  120  to manage power consumption. In various embodiments of the invention, power control circuit  118  is implemented on conductor  202  of USB printer cable  116 , which carries a nominal V BUS  voltage of 5V. Those of skill in the art will be aware that the V BUS  conductor, generally implemented on pin  1  of a USB cable, is capable of supplying power to unpowered USB peripherals. The V BUS  conductor can also be used by a host computer to manage power events such as suspend or resume, typically through the implementation of USB software on the host.  
         [0024]     However, internal power control circuit  118  of the present invention does not require implementation of software. Instead, it monitors the presence of a logic high (e.g., +5V) signal on conductor  202  of USB cable  116 . If present, it will conduct the signal and maintain the printer&#39;s current power state. When host information handling system  100  is turned OFF or transitions to an inactive state, conductor  202  of USB cable  116  goes to a logic low (e.g., 0V) signal, which causes power control circuit  118  to transition to an OFF state, which in turn transitions printer  120  to an OFF power state. In various embodiments of the invention, the manual power switch of printer  120  overrides power control circuit  118  of the invention, requiring no change in normal user operation.  
         [0025]      FIG. 2   c  is generalized block diagram of an alternate embodiment of the invention wherein power control circuit  118  is implemented on USB cable  116  to manage power consumption of printer  120 . In various embodiments of the invention, power control circuit  118  is implemented on conductor  202  of USB printer cable  116 , and monitors the presence of a logic high (e.g., +5V) signal. If present, it will conduct the signal and maintain the printer&#39;s current power state. When host information handling system  100  is turned OFF or transitions to an inactive state, conductor  202  of USB cable  116  goes to a logic low (e.g., 0V) signal, which causes power control circuit  118  to transition to an OFF state, which in turn transitions printer  120  to an OFF power state. In various embodiments of the invention the manual power switch of printer  120  overrides power control circuit  118  of the invention, requiring no change in normal user operation.  
         [0026]      FIG. 3  is a generalized schematic diagram of one embodiment of the present invention. In one embodiment of the invention, power control circuit  118  comprises resistive load  306  and transistor  308  and is implemented between incoming USB V BUS  conductor  304 , which carries a nominal voltage of 5V from I/O device interface  104  coupled to information handling system  100 , outgoing USB V BUS  conductor  304  coupled to printer  120 , and ground conductor  310  of USB cable  116 .  
         [0027]     In this embodiment, power control circuit  118  monitors the presence of a logic high (i.e., +5V) signal on incoming USB V BUS  conductor  304 . As long as information handling system  100  controlling printer  120  is in an ON state, incoming USB V BUS  conductor  304  will supply +5VDC to transistor  308  of power control circuit  118 , which will conduct the incoming V BUS  voltage and the printer will maintain its current power state. When information handling system  100  is turned OFF or transitions to an inactive state, incoming USB V BUS  conductor  304  of USB cable  116  goes to logic low state (i.e., 0V), which causes transistor  116  of power control circuit  118  to transition to an OFF state, which in turn transitions printer  120  to an OFF power state. The manual power switch of printer  120  is operable to override power control circuit  118  of the invention, requiring no change in normal user operation.  
         [0028]     Skilled practitioners in the art will recognize that many other embodiments and variations of the present invention are possible. In addition, each of the referenced components in this embodiment of the invention may be comprised of a plurality of components, each interacting with the other in a distributed environment. Furthermore, other embodiments of the invention may expand on the referenced embodiment to extend the scale and reach of the system&#39;s implementation.