System and method for diagnosing a printing device based on a correlation coefficient between print volume and error rate

A method to determine an operating status of an image forming device comprises: monitoring a plurality of operating parameters of the image forming device during a first time interval; calculating a correlation coefficient during a second time interval between at least two of the plurality of operating parameters; identifying the image forming device as an abnormal operating status when the correlation coefficient calculated during the second time interval is a positive correlation coefficient above a predetermined level associated with a model of the image forming device; and determining a maintenance action for the image forming device based on the abnormal operating status.

TECHNICAL FIELD

The present application in general relates to printing devices, and more specifically, to a system and method for diagnosing an image forming device based on a correlation coefficient between print volume and error rate.

BACKGROUND

In order to properly maintain image forming devices such as printers, copiers, facsimile, and multi-function peripherals, remote management systems have been designed to collect various items of management information, such as maintenance management information, working state and failure information of the image forming devices. Most remote management systems are network based. Thus, most image forming devices may be coupled to a communication network so that the connection between the image forming devices and a central management device is established via the network.

The monitoring server may collect information regarding the image forming device such as the number and kind of prints the image forming device has performed and other aspects of its current state and/or operation. This information may be stored so that historical records of incidents that occur for the image forming device may be maintained. An incident may include a hardware or software issue.

The image forming device needs to be available for normal operations, such as printing, scanning, copying and other functions, for as long as possible with a minimum number of errors. With the printing function, it is desirable for the image forming device to produce print volume as efficiently as possible. When the image forming device is in a good operating status, it produces high print volume with minimum errors. If the image forming device has one or more parts with degradation or operating problems, the number of errors correlates with print volume. For instance, if a paper feeder has a mechanical problem, then the rate of paper jams will depend on number of printed pages.

Diagnostics of problematic image forming devices may be developed based on information about the amount of errors monitored and the number of pages printed. A maximum number of accepted errors may be predetermined by manufacturer specification for each device model. For instance, a maintenance specification can determine a normal failure rate as Mean Time Between Failure (MTBF), which equals one thousand pages between paper jams as a threshold. In a simple exemplary case, if only one jam error happens every 1,000 printed pages—the image forming device may be associated with a normal operating status.

Otherwise, the maintenance service should be scheduled for this printing device if jam happened more frequently than one thousand pages:

The value of MTBF can vary for different device models and different types of maintenance (service) contracts. For instance, device model ‘Venus1’ can be associated with MTBF=3,000 pages, while model ‘Mercury1’ can have MTBF=5,000 pages.

Method of diagnosis, symptoms and criteria of diagnostics can vary for different types of errors: mechanical errors as paper jams have different criteria of diagnostics, compared to software errors. Software or firmware errors mostly relate to network problems, user settings and image quality. Software/firmware errors have little correlation with printer's print volume, while mechanical failure directly relates to printer's print volume and is caused by degradation of mechanical parts. In cases when the image forming device has hardware issues, a service technician can schedule maintenance work that includes: parts cleaning, parts replacement and/or replacing entire device with new model for customer satisfaction.

A mathematical correlation function builds a numerical coefficient that reflects similarity of two series of variables, or measures similarity in terms of increasing and decreasing values of two variables. If the similarity is high, then the two variables are dependent. For example, if both variables increase and decrease in value synchronously, the correlation and dependency between these two variables is high. A correlation coefficient between print volume and failure rate can be an indicator of a good or bad operating status of the printing device, and it can be used as an indication of necessary service or maintenance work.

Therefore, it would be desirable to provide a system and method to diagnose image forming devices based on a correlation coefficient between print volume and error rate.

SUMMARY

In accordance with one embodiment, a method to determine an operating status of an image forming device is disclosed. The method comprises: monitoring a plurality of operating parameters of the image forming device during a first time interval; calculating a correlation coefficient between at least two of the plurality of operating parameters monitored during a second time interval; identifying the image forming device as an abnormal operating status when the correlation coefficient calculated during the second time interval is a positive correlation coefficient above a predetermined level associated with a model of the image forming device; and determining a maintenance action for the image forming device based on the abnormal operating status.

In accordance with one embodiment, a method to determine an operating status of at least one image forming device is disclosed. The method comprises: monitoring a plurality of operating parameters of the at least one image forming device during a first time interval, wherein monitoring a plurality of operating parameters of at least one image forming device comprises: determining a total number of pages printed by the at least one image forming device during the first time interval; and determining a total number of errors recorded by the at least one image forming device during the first time interval; calculating a correlation coefficient of the at least one image forming device during a second time interval; identifying the at least one image forming device as an abnormal operating status when the correlation coefficient is a positive correlation coefficient above a predetermined threshold level associated with a model of the at least one image forming device; and determining a maintenance action for the desired image forming device based on the abnormal status.

In accordance with one embodiment, a system for indicating normal and abnormal operating conditions for an image forming device is disclosed. The system has a processor. A memory is coupled to the processor. The memory stores program instructions that when executed by the processor, causes the processor to: monitor a plurality of operating parameters of the image forming device during a first time interval by determining a total number of pages printed and a total number of errors recorded during the first time interval; calculate a correlation coefficient between the plurality of operating parameters during a second time interval; identify the image forming device as an abnormal operating status when the correlation coefficient calculated during the second time interval is a positive correlation coefficient above a predetermined level associated with a model of the image forming device; and determine a maintenance action for the image forming device based on the abnormal operating status.

DESCRIPTION OF THE APPLICATION

Embodiments of the exemplary system and method relates to a system and method for diagnosing image forming devices based on a correlation coefficient between print volume and error rate wherein data related to print volume and error rate are collected during a data sampling interval. The system and method may calculate a correlation coefficient at the end of each analytical time interval. Observation of a trend and/or changes in correlation coefficients during sequential analytical time intervals may be used as a basis for diagnosing an operating condition of the image forming device. If correlation coefficient increases in value and exceeds a predetermined threshold, the image forming device may be marked as having a certain level of degradation and maintenance work can be scheduled.

Referring now toFIG. 1, a system10(hereinafter system10) may be shown. The system10may have a monitoring server12. The monitoring server12may be coupled to one or more image forming devices14. The monitoring server12may be coupled directly to the image forming device14through a network16or may be coupled to the image forming device14through a print server18and the network16.

The image forming device14may be any type of device having printing capabilities. For example, the image forming device14may be a printer, a copier, a fax machine, a multi-function peripheral including a scanner and one or more of functions of a copier, a facsimile device, and a printer and/or other types of rendering devices. The image forming device14may be used for outputting a print job.

The print server18may be used to connect the image forming device14to one or more computing devices20over the network16. The network16may be a local area network (LAN), a general wide area network (WAN), wireless local area network (WLAN) and/or a public network. The print server18may accept print jobs from the computing device20and may send the print jobs to the appropriate image forming device14. The print server18may queue the jobs locally as print jobs may arrive more quickly than the image forming device14may be able to print. Alternatively, or in addition to, the computing device20may be directly coupled to the image forming device14.

Individuals22may use one or more computing devices20to send print jobs to the image forming device14via a printing application24loaded on the computing device20. The computing devices20may send the print jobs directly to the image forming device14or through the print server18. The computing devices20may be a client computer system such as a desktop computer, handheld or laptop device, tablet, mobile phone device, server computer system, multiprocessor system, microprocessor-based system, network PCs, and distributed cloud computing environments that include any of the above systems or devices, and the like. The computing device20may be described in the general context of computer system executable instructions, such as program modules, being executed by a computer system as may be described below.

The system10may have a monitoring server12. The monitoring server12may be coupled to the one or more image forming devices14. The monitoring server12may be coupled directly to the image forming devices14through the network16or may be coupled to the image forming devices14through the print server18and the network16. The monitoring server12may be used to monitor and record a plurality of different operating parameters related to the operation of the image forming devices14. The information may be error alerts, print volume, and the like. Error alerts may contain information relating to an issue being experienced by the image forming device14. The error alert may contain information such as, but not limited to: an error code relating to the type of error, location of the error, time of the error as well as other information pertaining to the error. This information may be sent directly from the image forming device14or from the print server18. The monitoring server12may calculate a correlation coefficient between the error alert and the print volume during predetermined time intervals. The correlation coefficient may be used as an indicator of the operational health of the image forming device as will be described below. If the correlation coefficient increases in value, it can trigger an indicator that the image forming device14has a certain level of degradation and the monitoring server12may signal the service computing device26to schedule maintenance work

Referring now toFIG. 2, monitoring server12may be described in more detail in terms of the machine elements that provide functionality to the systems and methods disclosed herein. The components of the monitoring server12may include, but are not limited to, one or more processors or processing units30, a system memory32, and a system bus34that couples various system components including the system memory32to the processor30. The monitoring server12may typically include a variety of computer system readable media. Such media may be chosen from any available media that is accessible by the monitoring server12, including non-transitory, volatile and non-volatile media, removable and non-removable media. The system memory32could include one or more personal computing system readable media in the form of volatile memory, such as a random access memory (RAM)36and/or a cache memory38. By way of example only, a storage system40may be provided for reading from and writing to a non-removable, non-volatile magnetic media device typically called a “hard drive”.

The system memory32may include at least one program product/utility42having a set (e.g., at least one) of program modules44that may be configured to carry out the functions of embodiments of the invention. The program modules44may include, but is not limited to, an operating system, one or more application programs, other program modules, and program data. Each of the operating systems, one or more application programs, other program modules, and program data or some combination thereof, may include an implementation of a networking environment. The program modules44generally carry out the functions and/or methodologies of embodiments of the invention as described herein. For example, a program module44in the monitoring server12may be configured to calculate a correlation coefficient between the error alert and the print volume during predetermined time intervals. The correlation coefficient may be used as an indicator of the operational health of the image forming device as will be described below.

The monitoring server12may communicate with one or more external devices46such as a keyboard, a pointing device, a display48, or any similar devices (e.g., network card, modern, etc.). The display48may be a Light Emitting Diode (LED) display, Liquid Crystal Display (LCD) display, Cathode Ray Tube (CRT) display and similar display devices. The external devices46may enable the monitoring server12to communicate with the image forming device14(FIG. 1), a service computing device26(FIG. 1) or other devices. Such communication may occur via Input/Output (I/O) interfaces50. Alternatively, the monitoring server12may communicate with one or more networks16(FIG. 1) such as a local area network (LAN), a general wide area network (WAN), and/or a public network via a network adapter52. The monitoring server12may be coupled to the one or more networks via a wired or wireless connection. As depicted, the network adapter52may communicate with the other components via the bus34.

Any combination of one or more computer readable media (for example, storage system40) may be utilized. In the context of this disclosure, a computer readable storage medium may be any tangible or non-transitory medium that can contain, or store a program (for example, the program product42) for use by or in connection with an instruction execution system, apparatus, or device. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

Referring now toFIG. 3, the image forming device14may be described in more detail in terms of the machine elements that provide functionality to the systems and methods disclosed herein. The components of the image forming device14may include, but are not limited to, one or more processors or processing units60, a system memory62, and a system bus63that may couple various system components including the system memory62to the processor60. The image forming device14may typically include a variety of computer system readable media. Such media could be chosen from any available media that is accessible by the image forming device14, including non-transitory, volatile and non-volatile media, removable and non-removable media. The system memory62could include one or more image forming device readable media in the form of volatile memory, such as a random access memory (RAM) and/or a cache memory. By way of example only, the system memory62may be provided for reading from and writing to a non-removable, non-volatile magnetic media device typically called a “hard drive”.

The system memory62may include at least one program product/utility64having a set (e.g., at least one) of program modules66that may be configured to carry out the functions of embodiments of the invention. The program modules66may include, but is not limited to, an operating system, one or more application programs, other program modules, and program data. Each of the operating systems, one or more application programs, other program modules, and program data or some combination thereof, may include an implementation of a networking environment. The program modules66may include procedures such as a page converter, rasterizer, compression code, page print scheduler, print engine manager, and similar printing applications (i.e., printer firmware). The program modules66generally carry out the functions and/or methodologies of embodiments of the invention as described herein.

The image forming device14may have one or more communication modules68. The communication modules68may allow the image forming device14to communicate with one or more networks (i.e., network16shown inFIG. 1) such as a local area network (LAN), a general wide area network (WAN), wireless local area network (WLAN) and/or a public network. In accordance with one embodiment, the communication modules68may include a network communication processing unit70A coupled to a network communication interface70B. The network communication processing unit70A and the network communication interface70B may allow the image forming device14to communicate with one or more networks16. These networks16may be a local area network (LAN), a general wide area network (WAN), a wireless local area network, a public network, a cellular network as well as other type of networks. The communication modules68may include a near field communication processing unit72A coupled to a near field communication interface72B. The near field communication processing unit72A and the near field communication interface72B may allow the image forming device14to communicate with other electronic devices located near the image forming device14using Bluetooth, infrared or similar wireless communication protocols.

The image forming device14may include an operation panel74. The operation panel may include a display unit76and an input unit78for facilitating human interaction with the image forming device14. The display unit76may be any electronic video display, such as a LCD display, LED display and similar display types. The input unit78may include any combination of devices that allow users to input information into the operation panel74, such as buttons, a keyboard, switches, and/or dials. In addition, the input unit78may include a touch-screen digitizer overlaid onto the display unit76that can sense touch and interact with the display unit76.

The image forming device14may have one or more sensors79. Each sensor79may be used to monitor certain operating conditions of the image forming device14. Sensors79may be used to indicate a location of a paper jam, document mis-feed, toner level, as well as other operating conditions. The above is given as examples and should not be read in a limiting manner. Each sensor79may be coupled to the processor60. When a sensor79detects an operational issue as may be disclosed below, the sensor79may send a signal to the processor60. The processor60may generate an error alert associated with the operational issue. The processor60may transmit the error alert to an external device as disclosed below using one of the communication modules68.

Any combination of one or more computer readable media (for example, system memory62) may be utilized. In the context of this disclosure, a computer readable storage medium may be any tangible or non-transitory medium that can contain, or store a program (for example, the program module66) for use by or in connection with an instruction execution system, apparatus, or device. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

Referring now toFIGS. 1-8, operation of the system10in accordance with one exemplary embodiment may be described. The monitoring server12may monitor the image forming devices14for a first predetermined time period. The first predetermined time period may be identified as a data sampling interval (DSI) and may be defined as a duration of time during which data is collected from the image forming device14. For example, as may be seen inFIG. 5, the monitoring server12may collect data from a plurality of image forming devices14. In the present example, the DSI is a day. However, this is just shown as an example and the DSI may be other predetermined time periods. The data collected during the DSI may be saved in a database within the monitoring server12. Each image forming device14may be associated with its own historical data collected during the DSI. As may be seen inFIG. 5, for each image forming device14being monitored (Device001, Model A and Device002, Model A), the print volume and error rate is recorded and stored in a database of the monitoring server12for each DSI interval. It should be noted that whileFIG. 5shows print volume and error rate, other operating parameters of the image forming devices may be monitored and recorded.

Graphs of the print volume and error rate for Device0001, Model A may be seen inFIG. 6. As may be seen, there is a relationship between the print volume and error rate. If the image forming device has one or more parts with degradation or operating problems, then there is a tendency for the number of errors to increase with print volume. WhileFIG. 6shows there is a relationship between the print volume and error rate, this should not be seen in a limiting manner. Relationships may be shown for other operating parameters of the image forming device14without departing from the spirit and scope of the present invention.

As disclosed above, a mathematical correlation function builds a numerical coefficient that reflects similarity of two series of variables, or measures similarity in terms of increasing and decreasing values of two variables. If the similarity is high, then the two variables are dependent. For example, if both variables increase and decrease in value synchronously, the correlation and dependency between these two variables is high. A correlation coefficient between print volume and failure rate can be an indicator of a good or bad operating status of the printing device, and it can be used as an indication of necessary service or maintenance work.

Pearson's correlation coefficient may be represented by the letter r and may be referred to as the sample correlation coefficient. So if we have one dataset {x1, . . . , xn} containing n values and another dataset {y1, . . . , yn} containing n values then that formula for r may be defined as:

r=∑i=1n⁢(xi⁢-x_)⁢(yi-y_)∑i=1n⁢(xi-x_)2⁢∑i=1n⁢(yi-y_)2
where:
n—is the sample size
xi, yi—are the single samples indexed with i
x—is the sample mean and analogously fory

Based on the above, sample correlation coefficients may be obtained based on the relationship between the number of error alerts recorded and the print volume recorded during a sampling time frame. However, as previously stated, correlation coefficients may be obtained for other operating parameters of the image forming device14without departing from the spirit and scope of the present invention.

After the monitoring server12collects the data during the DSI, each image forming device14may be monitored by the monitoring server12during a second time interval. The second time interval may be defined as an analytical time interval (ATI). The ATI may be: a week, a month, a year, or any time frame selected. The ATI may cover a series of data sampling intervals wherein data is collected and recorded each sampling interval. The number of data samples taken during the ATI may be based on usage of each image forming device14. For example, if the ATI is a week, the ATI may cover a typical 7 day week, i.e., Monday through Sunday, or a 5 day business week, i.e., Monday through Friday, based on image forming device14being monitored. Thus, if the image forming device14being monitored is used in a copy shop open 7 days a week, then the ATI may cover a typical 7 day week, wherein data samples are taken each day. Alternatively, if the image forming device14being monitored is used only during the week days, then the ATI may cover a 5 day business week, wherein data samples are taken Monday through Friday. The length of the ATI selected for the image forming device14may be based on the image forming device's performance, i.e., print volume and operating condition. For example, an image forming device14with low print volume can be associated with longer ATIs, such as every month, while image forming devices14with high print volumes can have shorter ATIs, such as every week.

At the end of each ATI, the monitoring server12may calculate and record the correlation coefficient based on the data monitored and recorded during the ATI. The correlation coefficient may be calculated as shown above based on the data obtained during the sampling intervals of the ATI. As may be seen inFIG. 7, each ATI may be associated with a device model of the image forming device14and a correlation coefficient calculated by the monitoring server12. InFIG. 8, the Device001, Model A is being monitored for three ATIs—ATI1, ATI2, and ATI3. Each ATI inFIG. 6covers 7 data sampling intervals. For each ATI, a correlation coefficient may be calculated by the monitoring server12. The correlation coefficient calculated is based on the relationship between the number of error alerts recorded and the print volume during each ATI. The correlation coefficient calculated by the monitoring server12may be used to indicate a current operating status of the image forming device14. For example, once the correlation coefficient between print volume and failure rate become positive and increases in value, the image forming device14may be indicating degradation of its mechanical parts.

In operation, the monitoring server12may monitor a plurality of image forming devices14. Referring toFIG. 8, a plot of the correlation coefficients calculated during an ATI for each image forming devices14may be seen. In the present embodiment, correlation coefficients of zero (0) or below may be considered as operating in a “Good” status, while correlation coefficients of above zero (0) may be considered as operating in “Anomalies” status. While a correlation coefficient of above zero (0) may be considered as operating in “Anomalies” status, it does not necessarily mean that the monitoring server12requires service as this may be based on whether the correlation coefficient calculated exceeds a threshold value associated with that particular make and model of the image forming devices14.

Observation of a trend and/or changes in the correlation coefficients during sequential ATIs may be used as a basis for diagnosing the operating status of the image forming device14. If the correlation coefficient increases in value, it can trigger an indicator that the image forming device14has a certain level of degradation and the monitoring server12may signal the service computing device26to schedule maintenance work. When the correlation coefficient increases in value and exceeds a predetermined threshold, the monitoring server12may mark the image forming device14with an anomalous operating status, and the monitoring server12may signal the service computing device26to schedule immediate maintenance work. It should be noted that the monitoring server12may be configured to send notifications such as emails, text messages and the like with a list of image forming devices14that recently had a positive and high value of correlation coefficients for one or more recent analytical time intervals to the operators of the image forming devices14in addition to or instead of signal the service computing device26to schedule maintenance work. Thus, in the embodiment shown inFIG. 8, Device003and099may be listed as requiring maintenance work if the correlation coefficient calculated exceeds their respective predetermined threshold values.

The predetermined threshold level may be provided by the manufacturer and/or be customized depending on the group of users using a particular set of image forming devices14given the image forming devices14are of the same model (i.e., an office may have 10 of the same model and the users may typically be low users of the printers. The threshold may be adjusted according to the type of user/office.).

It should be noted that different ATIs can have different threshold levels. The threshold levels may be adjusted based on usage or other operating factors. For example, if the ATI includes a holiday, the threshold level may be reduced due to the period of non and/or reduced use during the holiday period.