Patent Publication Number: US-6982810-B2

Title: Detecting theft of print substance from a printing device

Description:
TECHNICAL FIELD 
     This invention relates generally to printing devices, and more particularly to detecting theft of print substance from a printing device. 
     BACKGROUND 
     As computer technology has advanced the number of computers being used, as well as the tasks these computers are being used to perform, has increased. One significant area of advancement has been with portable computers, resulting in increasingly powerful computers being manufactured in small, easily mobile packages. Such mobility, in turn, has led to an increase in the desire for the availability of peripheral devices, such as printers, to computer users in non-traditional locations (that is, in locations other than at work or home). An example of such a non-traditional location is a hotel room—placement of a printer in a user&#39;s hotel room makes the printer readily available to the user when staying in that hotel room. 
     Unfortunately, in order for businesses to be willing to place peripheral devices in public places such as hotel rooms, these businesses need to be able to guard against theft of not only the devices themselves but also components of the devices. For example, printers typically include print substance stored in one or more cartridges (e.g., ink cartridges or toner cartridges) or refillable reservoirs. Because the print substance is used up during the normal process of printing, it is common for the printers to be designed so that the cartridges are easily replaceable or reservoirs easily refillable. However, by making such replacement or refilling easy, the print substance is also subject to easy theft. For example, an unscrupulous user could bring his or her own depleted ink cartridge to a hotel room and swap it for a near-full cartridge in the printer of that room. 
     One solution to guard against such theft is constant surveillance of the device (e.g., by video camera). However, such surveillance is costly and in many situations would be viewed by users as an unreasonable intrusion of their privacy. Another solution is to physically restrict access to the replaceable cartridges (e.g., by using a lock to which only appropriate staff have a key). However, this too has problems as it makes replacement of cartridges (or refilling of reservoirs) more cumbersome and also increases the cost of the printer by requiring either additional mechanisms to be manufactured for the locking mechanism or a different printer housing (which means that the standard commercial printers being manufactured cannot be used for public places, and that different printers need to be manufactured for use in public places). 
     Thus, it would be beneficial to provide a way to detect theft of print substance that did not have these problems. 
     SUMMARY 
     Detecting theft of print substance from a printing device is described herein. 
     According to one aspect, an amount of print substance in a printing device as well as an amount of print substance that should be in the printing device are identified. A difference between these amounts is determined and the difference compared to a threshold value. A determination that print substance has been removed from the printing device is made if the difference exceeds the threshold amount. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an exemplary printing environment in which print substance theft detection can be used. 
         FIG. 2  illustrates an exemplary monitoring system in additional detail. 
         FIG. 3  is a flowchart illustrating an exemplary process for detecting print substance theft. 
         FIG. 4  illustrates an exemplary computer in additional detail. 
     
    
    
     DETAILED DESCRIPTION 
     Detection of print substance theft is described herein. The print substance refers to the substance that is applied to paper or other print media during the printing process, such as ink or toner. Print substance levels in a printing device are monitored and levels that are inconsistent with the usage of the printing device are detected. Such inconsistencies allow for detection of theft of print substance from the printing device, such as a user&#39;s swapping of a depleted print cartridge for a full or near-full print cartridge from the printing device. 
       FIG. 1  illustrates an exemplary printing environment in which print substance theft detection can be used. Environment  100  includes a monitoring system  102  and numerous printing devices  104 ,  106 ,  108 , and  110 . Monitoring system  102  monitors print substance usage in each of the printing devices  104 – 110  and detects when print substance levels in the devices are inconsistent with usage of the devices. Printing devices  104 – 110  represent any one or more of a wide variety of conventional printing devices. Examples of such printing devices include printers, facsimile machines, multifunction machines (e.g., including scan, print, and facsimile functionality), etc. 
     Printing devices  104 – 110  can print in different ways and using different types of print substance. For example, the print substance may be ink or toner, and may be black and/or one or more other colors (e.g., secondary colors cyan, magenta, and yellow). The print substance can be stored within printing devices  104 – 110  in a variety of different manners, such as the use of ink cartridges, toner cartridges, and so forth. The print substance theft detection described herein monitors print substance levels, and thus can detect theft of an ink or toner cartridge or, alternatively, theft of print substance from within a cartridge or other substance reservoir. 
     Each of the printing devices  104 – 110  is coupled to monitoring system  102 , allowing information to be communicated between monitoring system  102  and each of the printing devices  104 – 110 . Any of a wide variety of conventional couplings may be used, including wired (e.g., twisted pair, coax, etc.) and/or wireless (e.g., RF, infrared, etc.) networks using any of a wide variety of public and/or proprietary communications protocols. Alternatively, rather than having a centralized monitoring system  102 , print substance usage may be monitored by the individual devices  104 – 110  and inconsistencies in print substance usage detected by the individual devices  104 – 110 . 
     Environment  100  represents any of a wide variety of environments in which print substance theft detection may be used. One such exemplary environment is a hotel in which each guest room is equipped with a printer. These printers are monitored from a location remote from the rooms, such as a secure office in the hotel or alternatively off-site (e.g., coupled to the printers in the hotel via the Internet). Other exemplary environments include “hospitality” areas (such as in airports, train terminals, highway rest areas, shopping malls, etc.), offices, college or university buildings or campuses, and so forth. 
     During operation, monitoring system  102  takes multiple readings of print substance level from the printing devices  104 – 110 . The differences in print substance levels at the times of these various readings, in combination with information obtained by monitoring system  102  regarding the usage of the printing devices during the times between the readings, are used by monitoring system  102  to detect print substance theft. 
       FIG. 2  illustrates an exemplary monitoring system  102  in additional detail, including a printer monitoring module  130 , one or more heuristics  132 , a comparator module  134 , and a warning module  136 . Printer monitoring module  130  communicates with the printing devices being monitored by system  102  to obtain readings of print substance level and printing device usage from the monitored devices. Heuristics  132  relate printing device usage to print substance usage (e.g., if fifty pages or 12,000 dots are printed, heuristics  132  can be used to identify how much print substance should have been used). Comparator module  134  compares the amount of print substance that should have been used by a printing device to an amount actually used, and warning module  136  analyzes the results from comparator module  134  and takes appropriate action based on the results. 
     During operation, printer monitoring module  130  takes a first reading of print substance level and printing device usage from a printing device being monitored (e.g., one of the printing devices  104 – 110  of  FIG. 1 ). The values of the first reading (the print substance level and printing device usage) are saved by module  130  and used as a base point to determine theft of the print substance after the time of this first reading. A reading is taken from a printing device by communicating a request for the desired information to the printing device. In one implementation, both system monitor  102  and the printing device support at least one of the current or proposed SNMP (Simple Network Management Protocol) versions, allowing the system monitor to request (and receive) this information from the printing device. When the printing device receives the request for the information from system monitor  102 , the printing device operates in a conventional manner to obtain the information and return it to system monitor  102 . 
     The indication of the usage of the printing device can take a variety of different forms, such as a page count (e.g., identifying a number of pages that have been printed on the printing device), a dot count (e.g., identifying a number of drops of ink that have been printed by the printing device), and so forth. Printing devices typically keep track of at least one of these usage indications. These may be from a fixed point in time (e.g., beginning when the printing device was manufactured) or a variable point in time (e.g., can be reset by a user or administrator). In implementations where the printing device keeps track of its usage based on a variable point in time that can be reset remotely, system monitor  102  may reset this point in time to be the time of the first reading of the print substance level rather than obtaining an indication of the printing device usage up to that point in time. 
     This first reading can be taken at a variety of different times or in response to a variety of different conditions. The timing of this first reading will vary by implementation based on the particular environment as well as administrator or designer desires. For example, in a hotel room the first reading may be taken when a guest checks into the hotel room, while in a college or university environment the first reading may occur at a particular time of day or day of week. By way of another example, the first reading may be taken whenever a print cartridge is replaced by an administrator or other staff person. Printer monitoring module  130  may be notified of this print cartridge replacement by the administrator or staff person, or alternatively automatically detect the replacement (for example, printer monitoring module  130  may be automatically notified by a printing device whenever a print cartridge has been removed (or alternatively an ink reservoir opened), or printer monitoring module  130  may poll, at regular or irregular intervals, the printing devices to determine whether the print cartridge has been removed). The printing device itself may employ a particular mechanism to determine when a print cartridge has been replaced or reservoir opened (e.g., a switch that is triggered when the cartridge is removed or cover to the reservoir opened), or alternatively replacement of a print cartridge or refilling of a reservoir may be automatically detected based on the print substance level changing from a low value to a high value. 
     After an amount of time has elapsed, printer monitoring module  130  takes a second reading of print substance level and printing device usage from the printing device. Print monitoring module  130  may be programmed or configured to take the second reading at a particular time or in response to a particular event, or alternatively module  130  may take the second reading when instructed to do so by another module or by a user. Analogous to the first reading, the timing of the second reading can vary (and may vary based upon different conditions) by implementation. For example, in a hotel room the second reading may be taken when the guest checks out of the hotel room. 
     The information obtained from the first and second readings are made available to comparator module  134 . Given the usage indications from the first and second readings, comparator module  134  can readily identify the amount that the printing device has been used between the two readings (for example, by subtracting the page count at the time of the first reading from the page count at the time of the second reading). Similarly, given the print substance levels from the first and second readings, comparator module  134  can readily identify the amount of print substance that has been used between the two readings (for example, by subtracting the print substance level at the time of the first reading from the print substance level at the time of the second reading). Thus, comparator module  134  can readily determine the amount of print substance used and the printing device usage between the two readings. 
     Comparator module  134  accesses heuristics  132  to determine, for the given amount of printing device usage, the amount of print substance that should have been used. Heuristics  132  are a set of one or more models that relate printing device usage to print substance usage. Thus, for a given amount of printing device usage, heuristics  132  can be used to identify how much print substance should have been used. For example, heuristics  132  may indicate for a particular printing device that if 100 pages were printed then 2% of the print substance should have been used. 
     Each heuristic  132  corresponds to a particular printing device. Situations may also arise where two or more printing devices are similar enough that the same heuristic  132  can correspond to each of the multiple printing devices. Heuristics  132  can be generated in a variety of different manners. In one implementation, a heuristic  132  for a particular printing device is determined by testing the printing device in a controlled environment by printing a variety of different documents and maintaining a record of printing device usage and print substance usage. Print substance usage is typically tested during development of the printing device, so this information it typically readily available. The heuristic for the printing device is readily generated from this information (e.g., the amount of print substance (as a percentage of the total amount of the print substance that the printing device can hold) used for a particular number of pages printed (or dots printed)). In another implementation, a heuristic  132  for a particular printing device is determined by testing the printing device in a somewhat secure environment (e.g., in an office(s) of a company that makes the printers accessible to employees of the company but not accessible to the public as a whole). A record of the printing device usage and print substance usage can then be kept over an extended period of time, and used to create the heuristic  132  for that printing device. 
     Depending on the type of printing device involved, one or more comparisons may be made. For example, in a black and white printer there is typically only one print substance cartridge or reservoir that needs to be monitored. However, in a color printer there are typically multiple print substance cartridges or reservoirs that need to be monitored (e.g., one for black and another for color, or one for black and multiple cartridges for color (such as one cartridge per secondary color cyan, magenta, and yellow)). In situations where there are multiple print substance cartridges or reservoirs to be monitored, and the printing device tracks printing device usage for the individual cartridges or reservoirs (e.g., dot counts per print cartridge), then heuristics  132  relate the printing device usage to the print substance usage for each cartridge or reservoir. For example, heuristics  132  would identify how much print substance is used for each cartridge or reservoir in a printing device for a particular number of pages printed (or dots printed). Thus, theft of only one of multiple cartridges in a printer can be detected. 
     Given the amount of print substance that should have been used and the amount of print substance that was used, comparator module  134  can readily generate a difference between the two print substance values. This difference is then communicated to warning module  136 . Warning module  136  analyzes the difference between the two print substance values and, based on the results of the analysis, takes appropriate action. In one implementation, warning module  136  compares the difference to a threshold value. If the difference does not exceed the threshold value then warning module  136  determines that no mischief has occurred. However, if the difference exceeds the threshold value then warning module  136  detects that some sort of mischief has occurred (e.g., a print cartridge has been stolen) and operates to warn a user or administrator (e.g., a hotel clerk or manager). The exact value of this threshold will vary, based on the particular device, the accuracy of the printing process, and the accuracy of the print substance level monitoring. For example, the threshold may be 1% for some devices, but 5% for other devices. Warning module  136  may be pre-programmed with the different thresholds for different printing devices, or alternatively obtain the different threshold values from another device (or component of monitor  102 ). 
     Warning module  136  may also take into account additional factors in determining whether mischief has occurred, such as whether an ink cartridge has been removed (e.g., which printer monitoring module  130  may automatically detect, as discussed above). This can be factored in to the analysis performed by warning module  136 . For example, if the difference in print substance levels is close to the threshold value (e.g., within another threshold amount of the threshold value) and the print cartridge has been removed, then warning module  136  may detect that mischief has occurred even though the threshold level has not been exceeded. 
     The warning issued by warning module  136  can take any of a variety of forms. For example, an audible or visual alarm may be sounded or displayed at system monitor  102 , a visual warning may be presented to a user (e.g., on the hotel clerk&#39;s screen as he or she is checking a guest out of the hotel), a log entry may be made for subsequent analysis, and so forth. In addition, other automated actions may be taken by warning module  136 , such as automatically charging a customer&#39;s credit card or account for the cost of the stolen print substance (e.g., the cost of a new print cartridge), automatically adding the cost of the stolen print substance to the user&#39;s bill (e.g., to be displayed on the user&#39;s bill for the hotel), and so forth. 
       FIG. 3  is a flowchart illustrating an exemplary process  150  for detecting print substance theft. The process of  FIG. 3  is carried out by a monitoring device, such as system monitor  102  of  FIGS. 1 and 2 , and may be performed in software. 
     Initially, an amount of print substance used is determined (act  152 ) as well as an amount of print substance that should have been used (act  154 ). These two amounts are compared (act  156 ) and a determination made as to whether the two amounts differ by greater than a threshold amount (act  158 ). If the two amounts differ by greater than the threshold amount then mischief is detected and appropriate action taken (act  160 ). However, if the two amounts do not differ by greater than the threshold amount, then no mischief is detected and no additional action need be taken (act  162 ). 
     It should be noted that the acts of process  150  can be implemented in an order different than the order illustrated in  FIG. 3 . For example, act  154  could be performed concurrent with or prior to act  152 . 
     In the discussions herein, reference is made to determining an amount of print substance that should have been used based on the amount of printing device usage. Alternatively, the opposite determination may be made—the amount the printing device should have been used may be determined based on the amount of print substance used. Subsequent analyses would similarly be modified to account for this reversal (e.g., comparing the difference between the amount the printing device was actually used and the amount the printing device should have been used to a threshold value). 
       FIG. 4  illustrates an exemplary computer  200  in additional detail. Computer  200  can be, for example, a system monitor  102  of  FIG. 1  or  FIG. 2 . Computer  200  represents a wide variety of computing devices, such as desktop computers, portable computers, dedicated server computers, multi-processor computing devices, personal digital assistants (PDAs), handheld or pen-based computers, microcontroller-based electronic devices, and so forth. 
     Computer  200  includes a processor  202 , a memory  204 , a mass storage device  206 , and an input/output (I/O) interface  208 , all coupled to a bus  210 . Bus  210  represents one or more buses in computer system  200 , such as a system bus, processor bus, accelerated graphics port (AGP), peripheral component interconnect (PCI), universal serial bus (USB), and so forth. The bus architecture can vary by computing device as well as by manufacturer. I/O interface  208  is a conventional interface allowing components of computer  200  (e.g., processor  202 ) to communicate with other computing devices via a network. I/O interface  208  may be, for example, a modem, a network interface card (NIC), and so forth. 
     Memory  204  represents volatile and/or nonvolatile memory used to store instructions and data for use by processor  202 . Typically, instructions are stored on a mass storage device  206  (or nonvolatile memory) and loaded into a volatile memory  204  for execution by processor  202 . Additional memory components may also be involved, such as cache memories internal or external to processor  202 . Various embodiments of the invention may be implemented, at different times, in any of a variety of computer readable media that is part of, or readable by, computer  200 . For example, such computer readable media may be mass storage device  206 , memory  204  or a cache memory, a removable disk (not shown) that is accessible by processor  202  or another controller of computer  200  (such as a magnetic disk or optical disk), and so forth. 
     Computer  200  is exemplary only. It is to be appreciated that additional components (not shown) can be included in computer  200  and some components illustrated in computer  200  need not be included. For example, a display adapter, additional processors or storage devices, additional I/O interfaces, and so forth may be included in computer  200 , or mass storage device  206  may not be included. 
     The discussions herein refer primarily to software components and modules that can be executed by a computing device. It is to be appreciated, however, that the components and processes described herein can be implemented in software, firmware, hardware, or a combination thereof. By way of example, a programmable logic device (PLD) or application specific integrated circuit (ASIC) could be configured or designed to implement various components and/or processes discussed herein. 
     Although the description above uses language that is specific to structural features and/or methodological acts, it is to be understood that the invention defined in the appended claims is not limited to the specific features or acts described. Rather, the specific features and acts are disclosed as exemplary forms of implementing the invention.