Source: http://www.google.com/patents/US7373094?dq=456322
Timestamp: 2015-05-07 05:11:46
Document Index: 307806804

Matched Legal Cases: ['Application No. 2003', 'Application No. 2002', 'Application No. 2002', 'art 4', 'art 4', 'art 4', 'Application No. 2002', 'art 112', 'art 113']

Patent US7373094 - Fixing unit having a plurality of heaters, image forming apparatus and ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA fixing unit thermally fixes a toner on a recording medium by a fixing member having a plurality of internal heaters and an outer peripheral surface, and a temperature sensor detects a surface temperature of the fixing member at a temperature detecting position. At least one first heater, of the heaters,...http://www.google.com/patents/US7373094?utm_source=gb-gplus-sharePatent US7373094 - Fixing unit having a plurality of heaters, image forming apparatus and method of determining temperature detecting position of temperature sensorAdvanced Patent SearchPublication numberUS7373094 B2Publication typeGrantApplication numberUS 11/582,991Publication dateMay 13, 2008Filing dateOct 19, 2006Priority dateApr 1, 2003Fee statusPaidAlso published asUS7130555, US20040258426, US20070036573Publication number11582991, 582991, US 7373094 B2, US 7373094B2, US-B2-7373094, US7373094 B2, US7373094B2InventorsKazuhito Kishi, Yasuhisa Kato, Akiyasu Amita, Masami Okamoto, Yasutada Tsukioka, Hiromasa TakagiOriginal AssigneeRicoh Company, Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (35), Non-Patent Citations (3), Referenced by (18), Classifications (8), Legal Events (1) External Links: USPTO, USPTO Assignment, EspacenetFixing unit having a plurality of heaters, image forming apparatus and method of determining temperature detecting position of temperature sensor
US 7373094 B2Abstract
a fixing unit configured to fix the toner image on the recording medium,
a heat roller having three or more heaters, including two or more main heaters; and
a temperature sensor configured to detect a temperature of the heat roller,
wherein the main heaters are disposed at positions closer to the temperature sensor than other heaters of the heat roller.
2. The image forming apparatus as claimed in claim 1, wherein the main heaters constantly receive power during a fixing operation.
wherein the main heaters are disposed at positions that avoid heat generated from the main heaters from being blocked by other heaters of the heat roller, with respect to the temperature sensor.
two or more main heaters configured to receive power from an external power supply;
one or more auxiliary heaters configured to receive power from a capacitor;
a heat roller configured to be heated by the main and auxiliary heaters; and
wherein the main heaters are disposed at positions closer to the temperature sensor than the one or more auxiliary heaters.
5. The image forming apparatus as claimed in claim 4, wherein the heat roller is stationary when starting the image forming apparatus.
a temperature sensor configured to detect a temperature of the heat roller, wherein the main heaters are disposed at positions that avoid heat generated from the main heaters from being blocked by the one or more auxiliary heaters, with respect to the temperature sensor.
two main heaters configured to receive power from an external power supply;
two auxiliary heaters configured to receive power from a capacitor;
wherein the main heaters and the auxiliary heaters are alternately disposed along a circumferential direction of the heat roller.
8. An image forming apparatus adapted to form an image on a recording medium by an electrophotography technique, comprising:
an image forming unit configured to form a toner image on a recording medium;
a fixing unit configured to fix the toner image on the recording medium; and
a control unit configured to control power supplied to the fixing unit,
a heat roller having a plurality of heaters; and
wherein said control unit controls the power that is supplied to the plurality of heaters depending on the temperature detected by the temperature sensor, and
said plurality of heaters comprises at least one first heater and a plurality of second heaters that are symmetrically arranged along a circumferential direction of the heat roller relative to a center of the heat roller,
said second heaters generating main heat during operation of the fixing unit, and said first heater generating auxiliary heat when abruptly raising the temperature of the heat roller.
9. The image forming apparatus as claimed in claim 8, wherein said second heaters and said at least one first heater are alternately arranged along the circumferential direction of the heat roller.
10. The image forming apparatus as claimed in claim 8, wherein said plurality of heaters receive the power originating from a power supply that is controlled by the control unit based on the temperature detected by the temperature sensor.
said first heater generates the auxiliary heat based on power originating from a first power supply; and
said second heaters generate the main heat based on power originating from a second power supply,
said first and second power supplies being mutually different and being both controlled by the control unit.
12. The image forming apparatus as claimed in claim 11, wherein the first power supply comprises a battery.
13. The image forming apparatus as claimed in claim 12, wherein the battery comprises a capacitor.
14. The image forming apparatus as claimed in claim 12, wherein the second power supply comprises a commercial A.C. power supply.
15. The image forming apparatus as claimed in claim 8, wherein the first heater closest to a temperature detecting position where the temperature sensor detects the temperature of the heat roller is arranged at a position that avoids blocking the heat generated from one or more second heaters, so that the temperature of the heat roller at the temperature detecting position is substantially the same as the temperature at other positions of the heat roller.
16. The image forming apparatus as claimed in claim 8, wherein one of the second heaters closest to a temperature detecting position where the temperature sensor detects the temperature of the heat roller is the same distance from the temperature detecting position as or is closer to the temperature detecting position than a first heater which is closest to the temperature detecting position.
17. The image forming apparatus as claimed in claim 8, wherein the control unit controls power supplied to at least one of said first heater, and said second heaters, by PID control.
18. The image forming apparatus as claimed in claim 8, wherein:
said first heater comprises a heater part that extends substantially for the entire length of the heat roller along a longitudinal direction of the heat roller; and
said second heaters comprise one second heater having a center heater part that is configured to heat a center portion of the heat roller along the longitudinal direction, and another second heater having a pair of end heater parts that are configured to heat opposite end portions of the heat roller along the longitudinal direction.
19. The image forming apparatus as claimed in claim 18, wherein said center heater part and said pair of end heater parts partially overlap in the longitudinal direction of the heat roller. Description
This application is a Continuation of U.S. patent application Ser. No. 10/814,161, filed Apr. 1, 2004, now U.S. Pat. No. 7,130,555.
This application claims the benefit of a Japanese Patent Application No. 2003-098055 filed Apr. 1, 2003, in the Japanese Patent Office, the disclosure of which is hereby incorporated by reference.
The present invention generally relates to, and more particularly to fixing units and image forming apparatuses, and more particularly to a fixing unit having a battery for supplying power to a heater, an image forming apparatus having such a fixing unit, and a method of determining a temperature detecting position of a temperature sensor.
In the fixing unit, power is supplied to a heater so that the heater heats a fixing member such as a roller and an endless belt. The toner image on the recording medium is heated when the fixing member, such as the roller and the endless belt, contacts the recording medium. Conventionally, the power to the heater is supplied from a commercial A.C. power supply. However, a Japanese Laid-Open Patent Application No. 2002-174988 proposes a fixing unit which is designed so that the power to the heaters of the fixing unit is also supplied using a battery.
In other words, in a case where the fixing unit is started from a stopped state by turning ON a main power supply, for example, it takes time for the fixing unit to reach a usable state, and the fixing unit cannot be used for a waiting time until the usable state is reached. In order to reduce this waiting time, the Japanese Laid-Open Patent Application No. 2002-174988 supplies power to the heaters of the proposed fixing unit by using both the commercial A.C. power supply and the battery, so as to rapidly heat the fixing member to a reload temperature.
Still another object of the present invention is to provide an image forming apparatus adapted to form an image on a recording medium by an electrophotography technique, comprising an image forming unit configured to form a toner image on a recording medium; and a fixing unit configured to thermally fix the toner image on the recording medium, the fixing unit comprising a fixing member having a plurality of internal heaters, and an outer peripheral surface configured to fix the toner on the recording medium; and at least one temperature sensor configured to detect a surface temperature of the fixing member at a temperature detecting position, the plurality of heaters receiving power based on the surface temperature detected by the temperature sensor so that the surface temperature becomes a predetermined temperature, at least one first heater, of the plurality of heaters, being capable of receiving power from a battery, remaining second heaters, of the plurality of heaters, being capable of receiving power from an external power supply, a temperature distribution of the surface temperature when the first heater is ON and a temperature distribution of the surface temperature when the first heater is OFF having a difference-smaller than a predetermined value at the temperature detecting position. According to the image forming apparatus of the present invention, it is possible to safely and accurately control the surface temperature of the fixing member, and stably fix the toner image on the recording medium.
Another object of the present invention is to provide a method of determining a temperature detecting position of a temperature sensor which is configured to detect a surface temperature of a fixing member having a plurality of internal heaters which receive power based on the surface temperature detected by the temperature sensor, at least one first heater, of the plurality of heaters, being capable of receiving power from a battery, remaining second heaters, of the plurality of heaters, being capable of receiving power from an external power supply, the method comprising the steps of obtaining a first temperature distribution of the surface temperature when the first heater and at least one second heater is ON; obtaining a second temperature distribution of the surface temperature when the first heater is OFF and said at least one second heater is ON; and determining the temperature detecting position of the temperature sensor to a location where a difference between the first and second temperature distributions is smaller than a predetermined value. In this case, it is possible to determine the temperature detecting position of the temperature sensor which ensures safe and accurate control of the surface temperature of the fixing member.
Still another object of the present invention is to provide a method of determining a temperature detecting position of a temperature sensor which is configured to detect a surface temperature of a fixing member having a plurality of internal heaters which receiving power based on the surface temperature detected by the temperature sensor, at least one first heater, of the plurality of heaters, being capable of receiving power from a battery, remaining second heaters, of the plurality of heaters, being capable of receiving power from an external power supply, the method comprising the steps of obtaining a first temperature distribution of the surface temperature when no first heater is provided and at least one second heater is ON; obtaining a second temperature distribution of the surface temperature when the first heater is provided and at least one second heater is ON; and determining the temperature detecting position of the temperature sensor to a location where a difference between the first and second temperature distributions is smaller than a predetermined value. In this case, it is possible to determine the temperature detecting position of the temperature sensor which ensures safe and accurate control of the surface temperature of the fixing member.
FIG. 18 is a cross sectional view of the fixing unit cut along a line A-A in FIG. 16;
FIG. 19 is a cross sectional view of the fixing unit cut along a line B-B in FIG. 16;
FIG. 22 is a diagram for explaining a first embodiment of a method of determining a temperature detecting position of temperature sensor according to the present invention; and
FIG. 23 is a diagram for explaining a second embodiment of a method of determining a temperature detecting position of temperature sensor according to the present invention.
FIG. 2 is a circuit diagram showing a circuit structure of the fixing unit 90A. In FIG. 2, the heater 91 generates heat in response to the power supplied from an external power supply (commercial A.C. power supply) 87, and the heater 92 generates heat in response to the power supplied from a capacitor 88 which forms a battery. A temperature detection signal from the temperature sensor 3, which detects the surface temperature of the fixing roller 1A, is supplied to a CPU 83 via an input circuit 82. The CPU 83 controls the supply of power to the heater 91 via a driver 84 and a thermostat 86, and supplies the supply of power to the heater 92 via a switch SW, based on the temperature detection signal, so that the surface temperature of the fixing roller 1A becomes a set temperature. The capacitor 88 may be connected to a charging unit 89 and charged, by controlling a switch 85.
FIG. 4 is a diagram showing a relationship of the temperature detected by the temperature sensor 3 and the nip temperature in a vicinity of the nip part 4. In FIG. 4, the ordinate indicates the nip temperature in arbitrary units, and the abscissa indicates the temperature detected by the temperature sensor 3 in arbitrary units. When the temperature sensor 3 detects that the surface temperature of the fixing roller 1B has reached a reload temperature T1, the nip temperature in the vicinity of the nip part 4 has also reached a reload temperature Tnip (approximately equal to T1). Thereafter, the power supply is controlled so that the surface temperature of the fixing roller 1B at the position detected by the temperature sensor 3 and the nip temperature in the vicinity of the nip part 4 are maintained to the reload temperature (T1, Tnip).
On the other hand, if the capacitor has only been charged to such an extent that the capacitor is not capable of supplying power due to insufficient charging, for example, no power is actually supplied from the capacitor to the heater 93 even though a circuit similar to that shown in FIG. 2 is provided to enable the power supply from the capacitor to the heater 93. Consequently, the fixing roller 1B in this case is only heated by the heat generated from the heaters 94 and 95 which receive power from the external power supply.
In this embodiment, an outer peripheral surface of the pressure roller 2 is made of a sufficiently elastic material such as silicon rubber. However, a pressure member is not limited to the pressure roller 2, and a pressure member having other forms, such as an endless belt, may be used in place of the pressing roller 2. The pressure roller 2 presses against the fixing roller 1 at a predetermined nip pressure by an operation of a known pressing means (not shown). The pressing roller 2 is stationary at the time of starting the fixing unit 10, and rotates counterclockwise in FIG. 5 when the recording medium is passed through the nip part between the fixing roller 1 and the pressing roller 2. A known driving mechanism (not shown) drives and rotates the fixing roller 1 and the pressing roller 2. However, it is of course possible to drive and rotate only one of the fixing roller 1 and the pressing roller 2 by the driving mechanism.
The temperature sensor 3 is arranged at a temperature detecting position where the surface temperature of the fixing roller 1 is detected. This temperature detecting position is located at a diametrically opposite position from the nip part between the fixing roller 1 and the pressing roller 2, relative to a center shaft (not shown) of the fixing roller 1. The temperature sensor 3 may be formed by any temperature detecting means capable of detecting the surface temperature of the fixing roller 1, and the temperature detecting means does not need to make direct contact with the outer peripheral surface of the fixing roller 1 as long as it is possible to detect the surface temperature of the fixing roller 1. Hence, various contact type sensors and non-contact type sensors, including a radiation thermometer and a thermocouple (or thermoelectric) thermometer, may be used for the temperature sensor 3.
The capacitor is a D.C. power supply forming the battery. It is possible to use an electric double layer capacitor or the like having an electrostatic capacitance of the farad (F) order or greater. For example, the battery may be formed by a capacitor module which is made up of a plurality of capacitor cells which are connected in series and/or in parallel. In this case, each capacitor cell may have a capacitance of approximately 300 F to 1500 F at a rated voltage of 2.5 V, so as to realize a high output voltage of approximately 30 V to 200V from the capacitor module.
Next, a description will be given of an embodiment of the image forming apparatus according to the present invention, by referring to FIG. 15. FIG. 15 is a cross sectional view showing the embodiment of an image forming apparatus according to the present invention. For the sake of convenience, it is assumed that the image forming apparatus employs the fixing unit 10 shown in FIG. 5. However, the image forming apparatus may of course employ the fixing unit of any of the embodiments and modifications described above. Only parts of the image forming apparatus directly related to the subject matter of the present invention will be described with reference to FIG. 15, since the basic structure of the image forming apparatus shown in FIG. 15 are described in detail in the Japanese Laid-Open Patent Application No. 2002-174988.
FIG. 16 is a perspective view showing a part of the third embodiment of the fixing unit. FIG. 17 is a side view showing a fixing roller shown in FIG. 16. FIG. 18 is a cross sectional view of the fixing unit cut along a line A-A in FIG. 16, and FIG. 19 is a cross sectional view of the fixing unit cut along a line B-B in FIG. 16. Further, FIG. 20 is a diagram showing amounts of heat generated by heater parts of the heaters. In FIGS. 16 through 19, those parts which are essentially the same as those corresponding parts shown in FIGS. 5 through 14 are designated by the same reference numerals, and a description thereof will be omitted.
The temperature sensor 3-1 is provided with respect to the center heater part 112 as shown in FIG. 18, and the temperature sensor 3-2 is provided with respect to the end heaters part 113-1 as shown in FIG. 19. The temperature detecting positions of the two temperature sensors 3-1 and 3-2 are mutually different along the circumferential direction of the fixing roller 1, as may be seen by comparing FIGS. 18 and 19. Furthermore, the temperature sensors 3-1 and 3-2 are provided at positions which are substantially unaffected by the blocking of heat from the heaters 12 and 13 by the heater 11.
In this embodiment of the method of determining the temperature detecting position of the temperature sensor 3 which is configured to detect the surface temperature of the fixing roller 1 having the plurality of internal heaters 11 through 13 which receive power based on the surface temperature detected by the temperature sensor 3, at least the heater 11 is capable of receiving power from the battery, and the remaining heaters 12 and 13 are capable of receiving power from the external power supply such as the commercial A.C. power supply. The method includes the following steps:
ST1: To obtain a first temperature distribution TD1 of the surface temperature of the fixing roller 1 when the heater 11 is ON and the heater 13 (that is, at least one of the heaters 12 and 13) is ON;
ST2: To obtain a second temperature distribution TD2 of the surface temperature of the fixing roller 1 when the heater 11 is OFF and the heater 13 (that is, at least the above one of the heaters 12 and 13) is ON; and
ST3: To determine the temperature detecting position of the temperature sensor 3 to a location where a difference DIFF1 between the first and second temperature distributions TD1 and TD2 is smaller than a predetermined value.
In this embodiment of the method of determining the temperature detecting position of the temperature sensor 3 which is configured to detect the surface temperature of the fixing roller 1 having the plurality of internal heaters 11 through 13 which receive power based on the surface temperature detected by the temperature sensor 3, at least the heater 11 is capable of receiving power from the battery, the remaining heaters 12 and 13 are capable of receiving power from an external power supply such as a commercial A.C. power supply. The method includes the following steps:
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS4843214May 6, 1988Jun 27, 1989Ricoh Company, Ltd.Heat roll type arrangement for electrostatic recording apparatusUS5400123Jul 28, 1993Mar 21, 1995Ricoh Company, Ltd.Image forming apparatus capable of erasing an image recorded in a sheetUS5481350Feb 2, 1994Jan 2, 1996Ricoh Company, Ltd.Heat roller fixing device divided into first and second frames and with positioning members of the first frameUS5701556 *Dec 7, 1994Dec 23, 1997Fujitsu LimitedThermal fixing device having temperature controlUS5729798Feb 20, 1997Mar 17, 1998Ricoh Company, Ltd.Heat roller fixing device having positioning membersUS5745247Jan 27, 1995Apr 28, 1998Ricoh Company, Ltd.Image forming apparatus having a controlled fixing unitUS5839032Mar 25, 1997Nov 17, 1998Ricoh Company, Ltd.Image forming apparatus having selectably controlled sheet discharge pathsUS5854465Sep 20, 1995Dec 29, 1998Ricoh Company, Ltd.Thermal fixing device for an image forming apparatusUS5862436 *Oct 23, 1997Jan 19, 1999Hitachi Koki Co., Ltd.Fixing apparatus and method for electrophotographic apparatus including temperature detecting mechanism for heat rollerUS5978618 *Jul 7, 1997Nov 2, 1999Fujitsu LimitedImage forming apparatus with controlled heat sources in fixing unitUS6112047Mar 10, 1997Aug 29, 2000Ricoh Company, Ltd.Image forming apparatus having a substantially vertical sheet transport path and a relaying mechanism that cooperate to transfer a sheet to a sheet discharge sectionUS6134418Jul 15, 1999Oct 17, 2000Ricoh Company, Ltd.Image forming apparatus having a casing mounted to the apparatus at an upper portion of a stacking deviceUS6144832Sep 1, 1998Nov 7, 2000Ricoh Company, Ltd.No wrinkling sheet feeding apparatus, a fixing apparatus and an image forming apparatusUS6239864Apr 28, 1999May 29, 2001Ricoh Co., Ltd.Image forming apparatus with a paper positioning deviceUS6263185Oct 7, 1999Jul 17, 2001Ricoh Company, Ltd.Image forming apparatus with a scanner inputUS6394446Mar 8, 2000May 28, 2002Ricoh Company, LtdReverse feeding deviceUS6411795Feb 23, 2001Jun 25, 2002Ricoh Company, Ltd.Image forming apparatus with a two-sides image forming operationUS6542705Oct 1, 2001Apr 1, 2003Ricoh Company, Ltd.Electrophotographic heating apparatus, system, and methodUS6813464Feb 28, 2003Nov 2, 2004Ricoh Company, Ltd.Fixing device with a peeler and biasing devices and image forming apparatus including the sameUS6941088Aug 6, 2003Sep 6, 2005Ricoh Company, Ltd.Fixing device, image forming apparatus, methodUS6987936Jun 4, 2004Jan 17, 2006Ricoh Company, Ltd.Image forming apparatus, image forming method, and fixing unitUS7010255May 30, 2003Mar 7, 2006Ricoh Company, Ltd.Fixing device having a heating member and image forming apparatus including the sameUS7116923 *Mar 29, 2004Oct 3, 2006Ricoh Company, Ltd.Fuser provided with auxiliary power supply device to operate with varying powerUS7130555 *Apr 1, 2004Oct 31, 2006Ricoh Company, Ltd.Fixing unit having a plurality of heaters, image forming apparatus and method of determining temperature detecting position of temperature sensorUS7164870 *Nov 15, 2004Jan 16, 2007Ricoh Co., Ltd.Method and apparatus for image forming capable of effectively performing an image fixingUS20050123315Dec 7, 2004Jun 9, 2005Kazuhito KishiHeating device, fixing device using the heating device and image forming apparatus using the fixing deviceUS20060039713Aug 23, 2005Feb 23, 2006Kazuhito KishiFixing device, image forming apparatus including the fixing device, and fixing methodUS20060051112Sep 8, 2005Mar 9, 2006Susumu MatsusakaFixing device, image forming apparatus including the fixing device, and fixing methodUS20060051113Sep 8, 2005Mar 9, 2006Kazuhito KishiFixing device, image forming apparatus including the fixing device, and fixing methodUS20060051120Sep 9, 2005Mar 9, 2006Kazuhito KishiFixing device, image forming apparatus including the fixing device, and fixing methodUS20060051121Sep 8, 2005Mar 9, 2006Susumu MatsusakaFixing device, image forming apparatus including the fixing device, and fixing methodUS20060127118Aug 23, 2005Jun 15, 2006Kazuhito KishiImage forming apparatus and method to supply power to a fixing deviceUS20060133846Nov 22, 2005Jun 22, 2006Masami OkamotoHeating device, fuser device, and image forming apparatusUS20060237446Apr 18, 2006Oct 26, 2006Kazuhito KishiElectric power supply control device, heating device and fixing deviceJP2002174988A Title not available* Cited by examinerNon-Patent CitationsReference1U.S. Appl. No. 07/592,522, filed Oct. 4, 1990, Kato et al.2U.S. Appl. No. 08/487,641, filed Jun. 7, 1995, Yasui et al.3U.S. Appl. No. 09/409,587, filed Sep. 30, 1999, Kato et al.Referenced byCiting PatentFiling datePublication dateApplicantTitleUS7483664 *Oct 4, 2006Jan 27, 2009Xerox CorporationFusing apparatus having a segmented external heaterUS8213819 *May 5, 2009Jul 3, 2012Sharp Kabushiki KaishaFixing apparatus and image forming apparatusUS8331839Jan 14, 2011Dec 11, 2012Ricoh Company, Ltd.Gloss applicator and image forming apparatusUS8406648Sep 23, 2010Mar 26, 2013Ricoh Company, Ltd.Heating device, fixing device, and image forming apparatusUS8503898Feb 23, 2011Aug 6, 2013Ricoh Company, Ltd.Fixing device and image forming apparatusUS8655253May 25, 2012Feb 18, 2014Ricoh Company, Ltd.Glossing device and image forming apparatus incorporating sameUS8676104Dec 9, 2011Mar 18, 2014Ricoh Company, Ltd.Fixing device and image forming apparatusUS8682218Dec 9, 2011Mar 25, 2014Ricoh Company, Ltd.Fixing device and image forming apparatus incorporating sameUS8688021May 15, 2012Apr 1, 2014Ricoh Company, Ltd.Glossing device, fixing device, and image forming apparatus incorporating sameUS8693933Jul 13, 2011Apr 8, 2014Ricoh Company, Ltd.Endless belt assembly, fixing device, and image forming apparatus including a belt tracking mechanismUS8712264Mar 15, 2012Apr 29, 2014Ricoh Company, Ltd.Fixing device, fixing device control method, and image forming apparatusUS8755730Jun 20, 2012Jun 17, 2014Ricoh Company, Ltd.Glossing device and image forming apparatus incorporating sameUS8774692Jun 29, 2012Jul 8, 2014Ricoh Company, Ltd.Fixing device and image forming apparatus incorporating sameUS8792797Mar 2, 2012Jul 29, 2014Ricoh Company, Ltd.Fixing device, image forming apparatus, and heater control methodUS8849172Apr 24, 2012Sep 30, 2014Ricoh Company, Ltd.Glossing device, fixing device, and image forming apparatus incorporating sameUS8892015Feb 1, 2012Nov 18, 2014Ricoh Company, Ltd.Fixing device and image forming apparatus incorporating sameUS8918038Apr 7, 2011Dec 23, 2014Ricoh Company, Ltd.Fixing device and image forming apparatus incorporating sameUS8929789Mar 6, 2012Jan 6, 2015Ricoh Company, Ltd.Fixing device with resistance heating element capable of accurately generating heat and image forming apparatus with fixing device* Cited by examinerClassifications U.S. Classification399/69, 399/88, 399/330, 399/328, 399/334International ClassificationG03G15/20Cooperative ClassificationG03G15/2039European ClassificationG03G15/20H2P3Legal EventsDateCodeEventDescriptionSep 22, 2011FPAYFee paymentYear of fee payment: 4RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services