Patent Grant
7822352
The present invention relates to an article, system and method for thermally conditioning an image forming apparatus. The image forming apparatus may be an electrophotographic or ink printer, copier, fax, all-in-one device, or multipurpose device.
An image forming apparatus, such as a printer, copier, fax, all-in-one device, or multipurpose device may use developing agent such as toner, ink or other image forming substance, which may be disposed on media to form an image. The developing agent may be fixed to the media using an image forming apparatus, which may apply heat and/or pressure to the toner. The image forming apparatus may include a nip through which the media may be passed. The nip may be formed by a heating device opposing a roller, such as a pressure roller or a back-up roller. A component, such as a belt or film, may be included in the forming device, in proximity to the heating device to aid the transport of media through the fixing device nip.
In an exemplary form, the present invention relates to an apparatus, article and method for conditioning a component in an image forming apparatus that includes a lubricant. A heating device may be heated to a first selected temperature wherein the lubricant may exhibit a targeted viscosity and the heating device may be maintained at the first selected temperature for a selected period of time prior to moving the component.
The present invention relates to an article, apparatus and method for thermally conditioning an image forming apparatus. The thermal conditioning may, e.g., reduce stress in a component of the image forming apparatus. An image forming apparatus may include a printer, copier, fax, all-in-one device or a multifunctional device.
Referring now to
Covering the polymeric layer 118 may be an additional layer or sleeve 120. The additional layer 120 may incorporate low energy material such as polytetrafluoroethylene, perfluoroalkoxy, fluorinated ethylene propylene, fluoroelastomers and other fluoropolymers and combinations of fluoropolymers. The roller 112 may be driven by a motor M in communication with the roller 112.
The heating device 122 may include a number of elements. For example, the heating device may include a heater substrate 124, which may include one or more segments. The substrate may be composed of ceramic material. Furthermore the substrate may be electrically insulative, have a high thermal conductivity, a high heat resistance and/or a low thermal capacity. The heating device may also include one or more heat-generating electrical resistors 126. The resistors may extend along the length of the substrate 124. A temperature detecting element 128 may be included in the heating device 122. The temperature detecting element 128 may include a thermistor or a thermostat. The temperature detecting element 128 may be mounted in contact with the substrate member 124 and in one embodiment may be mounted on a surface of the substrate member 124 opposite an electrical resistor 126.
The heating device may communicate with a processor “C.” The processor may be a microprocessor 16 or other processor located within the printing or the fixing device 122. The heating device may be fixed to a holder 130. A thin layer of electrical insulation such as glass (not shown) may cover the electrical resistors 126. An additional component 132, such as a belt or film, may also be included that may surround the heating device 122.
The component 132 may be composed of a relatively high heat resistant and/or durable material such as a polymeric material. The polymeric material may include by way of example, but is not limited to, a polyimide, polyetherimide, polyetherketone, polyamide-imide, polyphenylene-sulfide, etc. The component 132 may also be an endless tube and may be between 40-100 microns in thickness. The component 132 may also include an outer layer (not illustrated) incorporating a relatively low surface energy material such as polytetrafluoroethylene, perfluoroalkoxy, fluorinated ethylene propylene, fluoroelastomers and other fluoropolymers and combinations of fluoropolymers and other materials.
A layer of relatively viscous lubricant or grease may also be applied to the inner surface of the component 132 that contacts the heating device 122. In that sense the lubricant or grease may be understood to be any material which engages the component and which may lubricate the component during a printing operation. The lubricant may be relatively viscous perfluoropolytrimethylene oxide (a repeating polymer of three fully fluorinated methylene moieties in a straight chain terminated by an oxygen.) The lubricant may be thickened or made more viscous by the addition of polytetrafluoroethylene spherical particles that may be between 0.1-1.0 microns in diameter. The grease may have an apparent viscosity, for example, of about 5300 milliPascal-seconds at 250 degrees C at shear rates of 300 per second. Furthermore, as the temperature of the grease increases, the viscosity of the grease may decrease.
As alluded to above, the media S may pass from a developer, where a developing agent or image forming substance may be deposited, to the heating device and roller. Prior to fixing, the toner (designated as “Ta” in
The component 132 may be subjected to a number of stresses. For example, a print job may be sent to an image forming apparatus when the image forming apparatus may be in a cold or unheated state. Abrupt acceleration of the component and/or abrupt increase in temperature of the heating device from the cold state may cause thermal and/or mechanical shock to the component. In some instances the shock may cause deformation of the component and may even render the component unusable if the shock is severe enough or reoccurring. Accordingly, the present invention in an exemplary embodiment may reduce or manage shock in the component 132.
In one embodiment, the heating device may be heated to provide a conditioning temperature Tc. The conditioning temperature Tc may be greater than ambient or room temperature. The conditioning temperature Tc may also allow for the viscosity of the lubricating grease to attain a desired flow condition which may then provide desired component lubrication. Accordingly, a conditioning temperature Tc may be identified for preheating in which the viscosity of the lubricant may reach a desired viscosity or flow value (μ) expressed in mPa-seconds. The flow value μ may be a particular flow value or a range of flow values.
It can be appreciated that the conditioning temperature Tc may vary for different types of lubricants or grease materials. It should also be appreciated that the conditioning temperature Tc may be a particular temperature range. In addition, the conditioning temperature Tc herein may be provided prior to printing (e.g. cold start mode) or whenever the image forming apparatus is in a mode of operation wherein it may be desirable to maintain the lubricant or grease at the targeted flow value μ, such as in a power saver mode.
Once it has been determined that the component 132 has been sufficiently heated at a desired temperature to where a desired viscosity may be established for the lubricant (e.g., grease), such as after a given time period, the component may then be rotated at a first speed, e.g. a warm-up speed or “SPw.” The warm-up speed may be less than the printing speed. The warm-up speed may therefore be, e.g., 1-99% of the printing speed, including all values and increments therebetween.
Additionally, another temperature adjustment or series of temperature adjustments may then occur in order to raise the temperature of the heating device up to a desired printing temperature. This may include sequencing the heating device to other higher temperatures or adjusting the heating device to a final desired printing temperature. The motor speed may also be increased to a desired printing speed “PS” prior to the start of printing.
Once a print job has been completed, one may keep the image forming apparatus in a condition wherein the heating device temperature may be set (e.g. cooled) to a desired conditioning temperature to maintain a desired flow value (μ) for the accompanying lubricant or grease, again expressed in mPa-seconds. For example, the image forming apparatus may enter into a standby mode (in which the heating device may typically be heated) and/or a power saver mode (in which the heating device typically does not have power consumption and is not heated). In either case, the heating device may be maintained at a conditioning temperature Tc wherein the lubricant viscosity μ may be controlled to a target flow value.
In connection with the control of lubricant viscosity μ as noted above, the temperature to maintain a desired lubricant viscosity μ may be a function of the grease chosen. This may also assure that desired lubrication may be present prior to the rotation of the component. One may therefore avoid the presence of a component that may be otherwise relatively weak or brittle. One may also now reduce or minimize the stress and/or wear that may develop on the component induced by motion in the absence of the thermally conditioned lubricant or grease. Thermal conditioning of the lubricant or grease may also reduce what may sometimes be referred to as component deformation and/or “component crinkling.” Furthermore, by providing a preheat time prior to rotation of the component, the component or at least the portion of the component present at, e.g. a nip, may reach a given desired temperature before motion may be induced. This may place the component in a more optimal state to allow for stress relief from the forces induced by component motion.
It may also be appreciated that by providing a first rotation speed for the component, wherein the component is rotated at, for example, a warm-up speed, a degree of acceleration shock may be avoided. A higher degree of acceleration shock may otherwise occur when the component is rotated almost instantaneously from a static state to the rotational velocities experienced in printing. This shock may also cause component deformation and/or “component crinkling.”
By switching into power saver mode it may be possible to comply with Energy Star® or Blue Angel™ requirements even though the temperature of the heating device may be maintained at all times to sustain the desired lubricant or grease viscosity μ. Energy Star® requirements are compiled by and may be available from the United States Environmental Protection Agency and the Department of Energy, Washington, D.C. Blue Angel™ requirements for printers, for example, are included in RAL-UZ 85 complied by and may be available from the Ral German Institute for Quality Assurance and Certification, Sankt Augustin Germany.
An exemplary embodiment of the present invention is illustrated in
The heating device may then be turned on at 216 in order to condition the component and the lubricant or grease. The heating device temperature Td may then be separately monitored and at 218 a determination may be made as to whether the actual heating device temperature Td is greater or equal to the targeted conditioning temperature Tc. If the heating device temperature Td is not equal to or greater than Tc the inquiry may be made again at 218. This inquiry may occur at a given time interval, such as between 1 and 50 milliseconds and any increment therebetween such as 10 ms, 11 ms, etc. Alternatively, the inquiry may occur at every clock pulse or a number of clock pulses of the processor.
If the heating device temperature Td is equal to or greater than the conditioning temperature Tc at 218, then the acclimation timer may be started and incremented at 220. An inquiry may then be made as to whether a sufficient amount of time has passed for the heating device to be acclimated at 222. If sufficient time has not passed then a new inquiry can be considered at 218 as to whether the heating device temperature Td is greater than or equal to the conditioning temperature Tc. Alternatively, an inquiry may made be made again as to whether a sufficient amount of time has passed for the heating device to acclimate at 222 without rechecking the heating device temperature Td (not illustrated.)
If sufficient time for the component to acclimate has passed at 222 wherein the lubricant or grease may achieve the desired viscosity, then the motor controlling the roller and/or the component may begin rotating at 224. The motor may begin at a first rotational speed that is less than the speed that may be necessary for printing. It should be appreciated that the first rotational speed may be less than half of the necessary speed for printing and that rotating the roller may also allow for warm-up of the roller.
It should be appreciated that if desired at 226, the heating device temperature Td may be incrementally adjusted upwards to a heating device temperature Td that may be necessary for actual printing. For example, the heating device may be ramped up to an intermediate temperature or it may be ramped up to printing temperature. At 228 an inquiry may be made as to whether the ramp-up is complete. If no, the system may continue to ramp the heating device temperature Td as necessary.
After warm up is completed at 228, a print request may then be considered at 310, referring to
Once a determination has been made that printing may be complete at 318, the image forming apparatus may turn off the motors at 322 and enter standby mode at 324 or power save mode at 336. In standby mode, the heating device temperature may be set at 326 to again provide a conditioning temperature for the lubricant or grease so that it again provides a targeted viscosity. The temperature of the heating device in standby mode may also remain at print temperature.
When in standby mode, a standby timing device may begin to determine if and/or when to enter a power save mode at 328. The standby timing device may be changed at 330. Then a determination of whether a print request has been made may occur at 332. If a print request has been made, then the image forming apparatus may turn on the motors to printing speed at 312. If a request has not been made then at a determination may then be made as to whether the standby timing device has expired at 334. If the standby timing device has not expired the count may be changed again at 330.
The image forming apparatus may enter power saver mode at 336 if the standby timing device has expired or alternatively, in place of entering standby mode at 324. In the context of the present invention, a power saver mode may be understood as any mode wherein the system may draw reduced power and in which the fuser assembly may be maintained at a given temperature. Accordingly, once in power saver mode the temperature of the heating device Td may again be set at 338 to provide a conditioning temperature or temperature range for the lubricant or grease so that it again provides target viscosity or viscosity range. It can be appreciated that when in power saver mode a continuous low heat may be applied by the heating device, which may provide the conditioning temperature for the lubricant or grease.
Accordingly, it should be clear that the conditioning temperature in power saver mode may again be sufficient to keep the lubricant at the desired viscosity μ. Once in power saver mode, a determination may be made as to whether a print request has been generated for the image forming apparatus at 340. If a printing request has not been made, then the heating device may remain or continue to adjust to maintain the conditioning temperature at 338. If a print request is issued at 340, then the heating device may be brought up to printing temperature at 342.
A determination may then be made as to whether the actual temperature of the heating device Td is equal to or greater than the printing temperature at 344. If the temperature is not greater than or equal to the printing temperature, then the inquiry may be made again at 344 after a desired time period such as between 1 millisecond and 50 milliseconds and any increment therebetween including 10 milliseconds, 16 milliseconds, etc. or after a desired number of clock pulses. The component motor may then be turned on to printing speed at 346. Once the motors are turned on, printing may begin at 314.
It may also be appreciated that the functionality described herein for the embodiments of the present invention may be implemented by using hardware, software, or a combination of hardware and software, either within the image forming apparatus or outside the image forming apparatus, as desired. If implemented by software, a processor and a machine readable medium are required. The processor may be of any type of processor capable of providing the speed and functionality required by the embodiments of the invention. Machine-readable memory includes any media capable of storing instructions adapted to be executed by a processor. Some examples of such memory include, but are not limited to, read-only memory (ROM), random-access memory (RAM), programmable ROM (PROM), erasable programmable ROM (EPROM), electronically erasable programmable ROM (EEPROM), dynamic RAM (DRAM), magnetic disk (e.g., floppy disk and hard drive), optical disk (e.g. CD-ROM), and any other device that can store digital information. The instructions may be stored on medium in either a compressed and/or encrypted format.
Accordingly, in the broad context of the present invention, and with attention to
The foregoing description is provided to illustrate and explain the present invention. However, the description hereinabove should not be considered to limit the scope of the invention set forth in the claims appended here to.
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