Patent Application
20060263105
Specific embodiments relate to methods of signaling user replacement of a fuser wiper within an image forming device such as a laser printer. Still more particularly, the invention relates to the storing of information within a print cartridge that is used by a print engine in order to cause a notification message to be generated informing a user that the fuser wiper should be replaced.
Inkjet and laser printers have become commonplace equipment in most workplace and home computing environments. Today, many printers are multi-functional sophisticated image forming devices capable of printing on a large array of recording media such as standard letterhead and paper envelopes as well as a host of specialized media. At the same time, printers have become more reliable and require less overall service, maintenance and repair than earlier models. Yet, the requirement for routine service and maintenance of certain essential printer components remains.
In an electrophotographic (EP) printer, unfused toner particles are electrostatically attracted to the media to form an image. In order for the image to be fixed permanently the media must be fused. A fuser combines high temperature and pressure to the toner until it is melted and forced to adhere to the media. As such, the fuser is a critical component in the overall image forming process of most EP image forming devices.
It is well known that a printer's fuser is subject to disrepair and/or failure due to lack of service. Some printer manufacturers report having to honor a relative large amount of warranty claims directly related to the fuser assembly. Most such claims can be directly traced to a lack of care on behalf of the customer who fails to take preventative measures to increase the fuser's life. Furthermore, it is known that many fuser failures can be attributed to the use of special media which can reduce the fuser's service life. In the case of special media, it may be necessary for the customer to service the fuser more often than when printing on normal media stock. Yet, in many cases the user forgets to service the fuser at recommended intervals or may not readily appreciate how the media he/she uses may be reducing fuser life.
As such, a means of extending the fuser's life and thereby also reducing warranty claims based on the disrepair or failure of a printer's fuser would be advantageous.
The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and together with the description and claims serve to explain the principles of the invention. In the drawings:
For simplicity the discussion below will use the terms “media”, “sheet” and/or “paper” to refer to a discrete unit of recording media. It should be understood, however, that this term is not limited to paper sheets, and any form of discrete recording media is intended to be encompassed therein, including without limitation, envelopes, transparencies, postcards, labels, special media and the like.
Referring now to the drawings,
Laser printer 10 also contains at least one input port, or in many cases several types of input ports, as designated by the reference numeral 18. Each of these ports would be connected to a corresponding input buffer, generally designated by the reference numeral 22 on
Once text or graphical data has been received by input buffer 22, it is commonly communicated to one or more interpreters designated by the reference numeral 28. A common interpreter is PostScript™, which is an industry standard used by many laser printers. To speed up the process of rasterization, a font pool and typically also a font cache may be stored in memory within most laser printers. Such font pools and caches supply bitmap patterns for common characters so that a graphics engine 30 can easily translate each such character into a bitmap using a minimal elapsed time.
Once the data have been rasterized, they are directed by a page queuing system 34 into a page buffer, which is a portion of RAM designated by the reference numeral 35. In a typical laser printer, an entire page of rasterized data is temporarily stored by the page queuing system 34 in the page buffer 35, although some of the more modern laser printers do not buffer an entire page's worth of data at one time, thereby managing to operate with a much smaller amount of RAM in a “partial page buffer.” The data within the page buffer 35 may be communicated in real time to a print engine designated by the reference numeral 36. Print engine 36 typically includes a laser light source (not shown) within its printhead, and its output 40 is the physical printing onto a piece of paper, which is the final print output from laser printer 10. Print engine 36 also may contain a programmable non-volatile memory device 42, in addition to registers contained within its ASIC 44 that may act as either RAM or ROM, as desired. Programmable memory device 42 could consist of a Flash type-device, or an NVRAM-type device, for example, or any other type of non-volatile memory device.
Still referring to
A portion of the RAM 15 is typically allocated for virtual memory for at least one interpreter, and on
The print cartridge, generally designated by the reference numeral 100, is used in typical printing devices available at the present time. For laser printers (or other types of electrophotographic printing devices), reference numeral 100 represents a replaceable EP print cartridge that contains toner material, as well as a photoconductive drum unit 132 (see
Laser printer 10 also includes a fuser assembly 200 which is used in an electrophotographic machine, such as laser printer 10, to fuse previously applied toner particles onto a surface of a print medium, such as paper. Typically, the fuser assembly 200 includes a fuser roll which presses the toner into the print medium. Also, the fuser roll is typically heated internally by a heating element, such as a fuser lamp, disposed therein.
Of course, certain printer-specific information as well the process logic for the print engine 36 may be stored within the programmable memory device 42. For example, according to the present invention, programmable memory device 42 may be used to store print engine code for implementing a “replace fuser wiper message” function, or similar operation, as described herein. As discussed in more detail below, printer logic within the image forming device, such as laser printer 10, may cause a notification message to be generated based on the information stored on the print cartridge 100, which is accessible by the print engine 36. Such printer logic may be contained within memory device 42 such that a notification message may be generated that indicates to a user that a fuser wiper should be replaced at some specified point in the print cartridge's life.
Some conventional EP print cartridges contain a non-volatile memory device, such as an EEPROM chip or an EPROM chip or other similar storage means. For purposes of the present invention, the cartridge 100 contains a non-volatile memory device 144 or memory chip that is programmable. Programmable memory device 144 could consist of a Flash type-device, or an NVRAM-type device, for example, or any other type of non-volatile memory device. According to one embodiment of the present invention, memory device 144 is used to store print cartridge status information which can be accessed by the print engine 36 and which is used to enable a “replace fuser wiper message” function to notify a user that it is time to replace the fuser wiper. Likewise, programmable memory device 42 may be used to store print engine code for implementing a “replace fuser wiper message” function, or similar operation, depending on what has been stored in memory device 144. Printer logic within the memory device 42 or elsewhere within printer 10 may then cause a notification message to be generated based on the information stored on the print cartridge 100. Thus, a notification message indicating to a user that a fuser wiper should be replaced at some specified point in the print cartridge's life may then be generated. It is contemplated that the print cartridge 100 would support such a function and, if not, that the printer logic and print engine 36 would still work (minus the “replace fuser wiper message” function) in printers that do not contain a cartridge supporting the “replace fuser wiper message” function.
It may be useful to be able to update some of the stored information contained in this memory device 144. One way of implementing such a “replace fuser wiper message” function may involve dedicating a portion of the memory device 144 to store status indicators about the print cartridge 100 at the time of manufacture and during use. For example, bit locations within the memory device 144 may be reserved to enable or disable the “replace fuser wiper message” function. One bit may be used to indicate the beginning of life of the print cartridge 100 such as when the cartridge 100 is first inserted into the printer 10. Additional bits may be used to indicate specified points in the cartridge's life when the fuser wiper should be replaced. Each of these bits may be programmed during cartridge manufacturing depending upon the cartridge configuration. Once the print engine 36 sends the notification, the bit for that specific point in life may be changed by the print engine to keep the notification from being sent again until the next time the fuser wiper should be replaced.
The capacity of the print cartridge 100 may also be specified in the memory device 144 and used by the print engine 36 to help determine the specified points to send the message. In this regard, it should be understood that specified time intervals for replacing the fuser wiper can depend on a variety of factors and the choice of timing may be left to the discretion of the individual cartridge manufacturer. For example, the specified interval for replacing the fuser wiper may be related to the amount of toner remaining in the print cartridge 100. If so, a sensor 145 may be used to help determine how much toner remains in the print cartridge 100 and the information may be communicated to print engine 36. Alternatively, the specified interval for replacing the fuser wiper may be related to the type of media being sent through the printer 10 which may reduce the fuser's life. (For example, it is known that labels with adhesive have a tendency to reduce fuser life.) Still other considerations may involve the number of image forming operations performed since the fuser wiper was last replaced, the type of print cartridge, the cartridge yield and the type of printer, as well as other factors. It should be understood that the invention should not be limited by any particular factor or set of factors used in determining the specified intervals for replacing the fuser wiper.
Other types of data could also be stored on the memory device 144, such as “usage” data. In many situations, such “usage” data will preferably be stored in a manner that cannot later be modified. This is a circumstance where the use of a write once-read often memory device could be used to advantage to track certain parameters relating to the usage history of this particular EP print cartridge 100. Moreover, programmable memory device 144 could be provided as a hybrid chip, such that a first portion is programmable multiple times by the printer, and that a second portion is only programmable once (thereby functioning as the write once-read often memory device described above).
Referring to
The toner/developer sub-assembly 110 depicted on
The cleaner housing sub-assembly 130 includes a cleaner reservoir 134, a PC drum 132, a cleaner wiper, and other internal components well known in the industry. The cleaner housing sub-assembly 130 extends to the right and above the toner/developer sub-assembly 110 such that a portion of the cleaner housing sub-assembly (at the reference numeral 140) will approach an internal portion of the main body of printer 10. This portion 140 that extends to the main body of the printer may include at least one memory device 144 that is arranged to make electrical contact with the circuits of the main printer body. In one embodiment, memory device 144 comprises a non-volatile memory device that, as described above, may be used to store information relating to printer 10 and print cartridge 100.
Fuser assembly 200 receives media with toner deposited thereon from the print cartridge 100 and applies heat and pressure to fuse the toner to the media and create a permanent image. In general, fuser assembly 200 uses a fuser hot roll 202 which, as shown, may be mounted directly onto a fuser frame 204. The print media (not shown) travels into a nip 206 between the fuser hot roll 202 and a pressure roll (not shown), and exits through a second nip (not shown) between a pair of exit rollers 208. Exit rollers 208 may be rotated at a somewhat greater linear velocity so as to produce a slight tension on the print media. This is also referred to as an “overdrive” configuration.
A fuser wiper 210 is provided for routine cleaning of the fuser hot roll 202 in order to remove undesired remnants from the fusing operation that could interfere with subsequent proper operation of the fuser assembly 200 and/or reduce print output quality. This problem is well known in the arts. Typically, fuser wiper 210 is an item that a user can easily remove and replace as part of normal maintenance to extend the life of the fuser assembly 200. However, it has been found that users of a printer having a print cartridge with a replaceable fuser wiper, such as fuser wiper 210, do not always replace them at recommended intervals, leading to reduced life of the fuser assembly 200. The present invention provides a means of generating a notification message to users that the fuser wiper 210 should be replaced.
To better understand the present invention, reference is made to
The RIP 150 also is in communication with a display 154, which preferably comprises a liquid crystal display that can show alphanumeric characters, as are commonly seen on laser printers. The RIP 150, using its programming located in the ROM and data located in its RAM and NVRAM, will control the information depicted on the display 154, and will also control the data flow to and from the engine controller 160.
The engine controller 160 may be part of the print engine 36 (see
Engine controller 160 is also in communication with an optically coupled toner “gas gauge sensor” 172, via an electrical conductor 174. Engine controller 160 is also in communication with the memory device 144 that is mounted to the cleaner housing sub-assembly 130 of the print cartridge 100 (see
On
In addition to counting the pulses that travel along electrical conductor 174, the engine controller 160 and the toner wheel 170 are also designed to determine how much toner material remains within the toner sump (or reservoir) 112. This feature is described in detail in U.S. Pat. No. 5,634,169. By analyzing the information provided by the toner wheel 170, it is possible to create a “gauge” of discrete steps that give a reliable indication as to the actual amount of toner material remaining within the toner reservoir 112 as the toner begins to empty from that reservoir. The gauge of discrete steps of remaining toner material is also referred to herein as a “toner gas gauge,” which uses a “gas gauge toner sensor” (“GGTS”) that indicates, after a certain amount of the toner material has been dispensed from the toner reservoir 112, the actual amount of remaining toner in the reservoir in discrete steps that are indicative as to the amount of grams of remaining toner material. Thus,
The memory device 144 may comprise a Dallas Semiconductor, Inc. integrated circuit, part number DS2432. Since the above-described memory device 144 is a secure memory device, it can be used to permanently record certain information about the status of the print cartridge and/or the usage of the printer and the print cartridge that cannot be later altered by a user, or anyone else for that matter. This feature is very useful in non-reusable cartridges since the incremental amount of toner that has been consumed by the printer using a particular print cartridge can be determined and stored in the EPROM. In this manner, fuser wiper replacement intervals may also be calculated based upon toner usage.
On the other hand, if it is desirable to be able to write data multiple times into the memory device 144, then an EEPROM-type device may be more suitable. As an alternative, memory device 144 could encompass both an EPROM chip (e.g., at reference numeral 146) and an EEPROM chip (e.g., at reference numeral 148), or a hybrid chip that includes certain memory elements of each type on a single substrate.
Having shown the various components and subsystems of image forming device according to the invention,
Memory device 144 may be configured as an integral chip on print cartridge 100 which may be utilized in order to enable a “replace fuser wiper message” function or other similar type of notification according to the invention. In one particular embodiment, memory device 144 is used to store at least two indicators as represented by bits “b0” and “b1”. Thus, one bit “b0” may be used to indicate to the print engine 36 that it should display a message at the beginning of life of print cartridge 100 and the other bit “b1” may be used to indicate that a message be generated at some specified time during the useful life of print cartridge 100. The value of these bits may be specified depending upon cartridge type and may be programmed at cartridge manufacture.
Once the print engine 36 causes a notification to be sent, the bit for that specific point in the cartridge's life may be changed by the print engine 36 to keep the message from being sent again. The capacity of the cartridge 100 may also be specified in the memory device 144 and used by the print engine 36 to help determine the specified point when to send the message.
As shown, print engine 36 has engine code 252 or “process logic” which provides the operational control portion of the print engine 36 that enables the “replace fuser wiper message” function as described herein. Thus, the engine code 252 can be adapted to first determine if a replace fuser wiper message at the beginning of cartridge life is specified for the print cartridge 100 by examining the value of bit “b0” in the memory device 144. If the “b0” bit indicates that a message should be displayed, a notification may be sent by the print engine 36 directing the RIP 150 to display a “Replace Fuser Wiper” message on operational/display panel 254. Next, the engine code 252 may re-write the value of “b0” indicating that the message has been sent.
The message at some specified later point of the print cartridge's life may be handled in a similar manner. Engine code 252 may first determine if a replace fuser wiper message at some specified point of cartridge's life is specified for the print cartridge 100 by examining the value of bit “b1” in the memory device 144. If bit “b1” indicates that a message should be displayed, engine code 252 may first determine if that specified point in cartridge life has been exceeded and, if so, a notification will be sent directing the RIP 150 to display a “Replace Fuser Wiper” message on the Display 254. The engine code 252 may then re-write the value of “b1” indicating the message has been sent. The value of “b1” after the message has been sent is the same as it would be in a memory device 144 that did not specify that this message be displayed at all.
Thus, the present invention provides a means of notifying a user that the fuser wiper should be replaced. This can be done originally when the print cartridge 100 is first inserted into the printer and/or at a later time as specified by the memory device 144. For example, using the RIP/engine interface 256, the print engine 36 may send a notification message to the RIP 150 (such as, for example, a “Replace Wiper Message Notify”) when a new print cartridge 100 is inserted into the printer 10 or when the print cartridge 100 otherwise indicates the need to post a “Replace Fuser Wiper” or similar message. When the RIP 150 receives this notify, it may set a flag in NVRAM (indicating that the printer is in a state requiring replacement of the fuser wiper) and enter an Intervention Required (IR) state (i.e., discontinue printing), posting a message to the operational/display panel 254. The message may take the form of the following notice to a user:
Replace Wiper then press GO
Pressing the GO button (not shown) on the operational/display panel 254 may cause the RIP 150 to post the following message to the operational/display panel 254 (while remaining in the IR state):
Wiper replaced? GO=yes STOP=no
If the user presses “GO” at this point, the RIP 150 may assume the user has replaced the fuser wiper 210. The RIP 150 may then clear the flag in NVRAM (indicating that the printer is no longer in a state requiring replacement of the fuser wiper) and exit out of the IR state. Alternatively, if the user presses “STOP” then the flag in NVRAM may not be cleared and the printer will exit out of the IR state so that the user can resume printing. This flag in NVRAM can then be read and used by the RIP 150 to post a “Replace Fuser Wiper” message to the display 254 at a later point in time, if appropriate (for example, if the user turns on the printer while the printer is in a state requiring replacement of the fuser wiper, as indicated by the flag set in NVRAM).
The “replace fuser wiper message” function may be further refined by using sensor 260 (in
It should be understood that modifications can be made to the invention in light of the above detailed description. The terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification and the claims. Rather, the scope of the invention is to be determined entirely by the following claims, which are to be construed in accordance with established doctrines of claim interpretation.
