Heater structure with recesses

Abstract

A heater structure includes a pair of first heat generation elements including one or more first recess portions and a pair of second heat generation elements including one or more second recess portions. Each of the pair of first heat generation elements has a first main heating area in a middle portion along a longitudinal direction. Each of the pair of second heat generation elements has second main heating areas on a first side and a second side. The one or more first recess portions are located on the middle portion of the pair of first heat generation elements. The one or more second recess portions are located on the first side and the second side of the pair of second heat generation elements. The one or more of the first recess portions and corresponding of the one or more second recess portions are oriented in opposite directions.

Description

Atty. Dkt. No.: 86344674HEATER STRUCTURE WITH RECESSESBACKGROUND

[0001] In general, an image forming apparatus refers to a device that may generate, print, receive, and transmit image data. For example, an image forming apparatus may refer to a printer, a scanner, a copier, a fax machine, or a multi -function peripheral implemented by integrating a plurality of functions of such devices. An image forming apparatus may output data to a printing medium using printing material in a cartridge. The image forming apparatus may include a heater structure to heat the printing medium to fuse the printing material on the printing medium.BRIEF DESCRIPTION OF THE DRAWINGS

[0002] FIG. 1 depicts a cross section view of an example fixing apparatus of an image forming apparatus.

[0003] FIG. 2 depicts an enlarged sectional view for a part B of the fixing apparatus of FIG. 1.

[0004] FIG. 3 depicts a cross-sectional view according to a line A-A’ of an example heater structure.

[0005] FIG. 4 depicts a cross-sectional view according to a line A-A’ of another example heater structure.

[0006] FIG. 5 depicts a cross-sectional view according to a line A-A’ of yet another example heater structure.

[0007] FIG. 6 depicts a cross-sectional view according to a line A-A’ of yet another example heater structure.

[0008] FIG. 7A depicts a table depicting setting values for heat generation amounts of the heater structure of FIG. 3 and FIG. 7B depicts a graph showing variations in temperature of an example belt of a fixing apparatus resulting from heat received from the heater structure of FIG. 3.

[0009] FIG. 8 depicts a first graph depicting fusing temperatures of printing materials on printing mediums resulting from heat received from the heater structure of FIG. 3 and a4894-9433-2367.1Atty. Dkt. No.: 86344674 comparative heater structure and a second graph depicting energy consumed by the heater structure of FIG. 3 and the comparative heater structure to cause the fusing temperatures of the first graph.

[0010] FIG. 9A depicts a graph depicting maximum temperatures of an example belt resulting from heat received from the heater structure of FIG. 4 and FIG. 9B depicts a table comparing fusing performance to heating lengths of the heater structure of FIG. 4.

[0011] FIG. 10 depicts a graph depicting temperature distributions of an example belt of an example fixing apparatus and an example printing material over an example nip width of the example fixing apparatus resulting from heat received from the heater structure of FIG. 3 and a comparative heater structure.

[0012] FIG. 11 depicts an example graph depicting variations in temperatures of an example belt of an example fixing apparatus over an example printing time resulting from heat received from the heater structure of FIG. 3 and a comparative heater structure.DETAILED DESCRIPTION

[0013] Reference is now made to the figures. Although the figures and aspects of the disclosure can show or describe structures herein as having a particular shape, it should be understood that such shapes are merely illustrative and should not be considered limiting to the scope of the techniques described herein. For example, the examples described herein can be implemented in any shape or geometry for any material or layer to achieve desired results. It should be understood that like reference numerals may refer to like elements throughout, repetitive descriptions of which may be omitted. It should be also noted that in the drawings, the dimensions of the features are not intended to be to true scale and may be exaggerated for the sake of allowing greater understanding.

[0014] An image forming apparatus (IF A) may be used to form a printing image on a printing medium (e.g., paper) using printing material in cartridges mounted in the IF A. The IFA may use the printing material in the cartridges to form the printing image on the printing medium. The IFA may include a fixing apparatus with a heater structure to apply heat onto the printing medium to fix the printing image on the printing medium. Such fixing apparatuses may include belts positioned between the heater structure and the printing medium to transfer the heat from the heater structure to the printing medium and to drive the printing medium4894-9433-2367.1Atty. Dkt. No.: 86344674 through the fixing apparatuses. However, when the printing medium is a narrow printing medium (e.g., a printing medium with a width that is smaller than a longitudinal length of the heater structure, etc.), the heat transferred from the heater structure to the belt may not be transferred to the narrow printing medium at sides (e.g., peripheral sides, etc.) of the belt. As a result, a large temperature differential may develop between a center of the belt that transfers the heat to the narrow printing medium and the sides of the belt that do not transfer the heat to the narrow printing medium, which may cause deterioration in a durability of the belt. It should be appreciated, therefore, that implementing heater structures in fixing apparatuses of IF As that reduce a temperature differential between the center of the belt and the sides of the belt may be of interest. Additionally, when printing on a printing medium, printing material on sides of the printing medium may become overheated (e.g., a temperature of the printing material on the sides of the printing medium may be above a temperature threshold, etc.), which may cause issues with the printing material being fixed to the sides of the printing medium. It should be appreciated, therefore, that implementing heater structures in fixing apparatuses of IF As that do not overheat printing material on the sides of various sizes of printing mediums (e.g., narrow printing mediums, wide printing mediums, etc.) may be of interest.

[0015] Examples disclosed herein provide a heater structure for a fixing apparatus of an image forming devices that may include a pair of first heat generation elements and a pair of second heat generation elements. The first heat generation elements may include one or more first recessed portions and the second heat generation elements may include one or more second recessed portions. The first heat generation elements may have a first main heating area in a middle portion along a longitudinal direction of the first heat generation elements. The second heat generation elements may have second main heating areas on a first side and a second side respectively of the second heat generation elements. The one or more first recessed portions may be located on the middle portion of the first heat generation elements being between a first side and a second side of the first heat generation elements. The one or more second recess portions may be located on the first side and the second side of the second heat generation elements. The first recess portions of the first heat generation elements and the second recess portions of the adjacent of the second heat generation elements may be oriented in opposite directions. The opposite orientation of the first recess portions of the first heat generation elements and the second recess portions of the adjacent of the second heat generation elements may reduce a temperature differential across a width of a belt of the4894-9433-2367.1Atty. Dkt. No.: 86344674 fixing apparatus in the longitudinal direction of the heater structure to reduce a deterioration of a durability of the belt. Additionally, the opposite orientation of the first recess portions of the first heat generation elements and the second recess portions of the adjacent of the second heat generation elements may reduce temperatures at sides of printing mediums to prevent overheating of printing material located at the sides of the printing mediums. In some examples, the opposite orientation of the one or more first recessed portions of the first heat generation elements and the one or more second recessed portions of the second heat generation elements may reduce an amount of energy consumed by the heater structure such that an energy efficiency of the image forming device utilizing the heater structure is high.

[0016] According to the example shown in FIG. 1, an example heater assembly 220 is shown. The heater assembly 220 may be included in an image forming apparatus (e.g., a printer, etc.). The image forming apparatus may be used to form a printing image on a printing medium P. The print medium P may be paper, cardstock, fabric, plastic, and / or any other material where the image forming apparatus may form the printing image. The fixing apparatus 200 may apply heat and / or pressure onto the print medium P after the print medium P such that a printing material image transferred to the print medium P by the image forming apparatus is fixed on the print medium P as a print image. As shown in FIG. 1, the fixing apparatus 200 includes a pressure roller 210 and a heater assembly 220 that face each other and rotate. The heater assembly 220 may increase a temperature of the print medium P in order to fix the printing material image on the print medium P. The pressure roller 210 may apply a pressure on the printing medium P positioned between the pressure roller 210 and the heater assembly 220 against the heater assembly 220 in order to fix the printing material image on the print medium P.

[0017] In some examples, the heater assembly 220 may include a heater structure 300 (e.g., a heater, a heater assembly, etc.) that may generate and provide heat to the print medium P positioned between the heater assembly 220 and the pressure roller 210 to increase the temperature of the print medium P in order to fix the printing material image on the print medium P. By way of example, when the printing material image on the print medium P is formed out of toner, the heat generated by the heater structure 300 and provided to the print medium P may melt the toner and cause the toner to fuse (e.g., bond, etc.) with fibers in the print medium P. As a result, the toner may solidify into the print medium P such that the printing material image is solidly fixed to the paper and cannot be easily rubbed off. The4894-9433-2367.1Atty. Dkt. No.: 86344674 heater structure 300 may be operated by the image forming apparatus (e.g., a controller of the image forming apparatus, etc.) to provide the heat to the print medium P in order to fix the printing material image on the print medium P. In some examples, the image forming apparatus may operate the heater structure 300 based on a size of the print medium P.

[0018] In some examples, the image forming apparatus may include sensors that generate sensor data associated with the heater structure 300. By way of example, the image forming apparatus may include a first sensor to generate first sensor data associated with a first heat generated by a first portion of the heater structure 300 and provided to the print material P and a second sensor to generate sensor data associated with a second heat generated by a second portion of the heater structure 300 and provided to the print material P. In some examples, the image forming apparatus (e.g., a controller of the image forming apparatus, etc.) receives the sensor data and operates the heater structure 300 based on the sensor data.

[0019] According to the example shown in FIG. 2, the heater assembly 220 may include a belt assembly 222 that contacts the print medium P to drive the print medium P through the fixing apparatus 200 and the heater structure 300 that generates and provides heat to the print medium P via the belt assembly 222 to increase the temperature of the print medium P in order to fix the printing material image on the print medium P. In some examples, the belt assembly 222 is driven by a motor (e.g., an electric motor, etc.) to drive the print medium P through the fixing apparatus 200. A width of the portion of the printing medium P that is contacted by the pressure roller 210 and the belt assembly 222 may be a nip width of the fixing apparatus 200 where the pressure roller 210 applies pressure on the printing material P and / or the heater assembly 220 provides heat to the printing material P. In some examples, the fixing apparatus 200 may include a variable nip width. For example, the fixing apparatus 200 may be alternated between a normal pressure configuration with a first nip width and a reduced pressure configuration with a second nip width smaller than the first nip width where the pressure roller 210 may apply less pressure on the printing medium P.

[0020] According to the example shown in FIG. 2, the belt assembly 222 may include a housing 224 (e.g., a casing, a tracked housing, etc.) and a belt 226 (e.g., a heating belt, etc.) wrapped around at least a portion of the housing 224. The belt 226 may contact the print medium P to drive the print medium P through the fixing apparatus 200. The housing 224 may define a heater opening 228 that receives the heater structure 300 such that the heater structure 300 is positioned between the housing 224 and the belt 226. In some examples, the4894-9433-2367.1Atty. Dkt. No.: 86344674 heater structure 300 may be coupled to the housing 224 when the heater structure 300 is received by the heater opening 228. As the heater structure 300 generates heat, the heater structure 300 may provide the heat to the print medium P through the belt 226. By way of example, the belt 226 may be driven (e.g., by a motor, etc.) to rotate around the housing 224 while contacting the heater structure 300. Portions of the belt 226 in contact may receive the heat generated by the heater structure 300 and transfer the heat to portions of the print medium P positioned between the belt 226 and the pressure roller 210. In some examples, the pressure roller 210 may apply pressure on the printing medium P positioned between the pressure roller 210 and the heater structure 300 against the heater structure 300 through the belt 226 in order to fix the printing material image on the print medium P. In other examples, the belt assembly 222 may not include the belt 226 and the heater structure 300 may directly contacts the printing medium P to transfer the heat generated by the heater structure 300 to the printing medium P.

[0021] In the example shown in FIG. 3, an example heater structure 300 (e.g., a heater assembly, a heater system, etc.) for an image forming apparatus (e.g., a printer, etc.) may generate and provide heat to a print medium (e.g., paper, cardstock, etc.) to fix a printing image formed by the image forming apparatus onto the print medium. As shown in FIG. 3, the heater structure 300 includes at least two first heat generation elements 310, shown as a first heat generation element 310a and an opposite first heat generation element 310b, to generate a first portion of the heat generated by the heater structure 300 and at least two second heat generation elements 340, shown as a second heat generation element 340a and an opposite second heat generation element 340b, to generate a second portion of the heat generated by the heater structure 300. According to the example shown in FIG. 3, the heater structure 300 includes a pair of the first heat generation elements 310 and a pair of the second heat generation elements 340. In other examples, the heater structure 300 may include a greater number of the first heat generation elements 310 and / or the second heat generation elements 340. In still other examples, the heater structure 300 may include a single of the first heat generation elements 310 and / or the second heat generation elements 340.

[0022] The heater structure 300 may have a heating length extending from a first side (e.g., a first lateral side, etc.) of the first heat generation elements 310 and / or the second heat generation elements 340 to a second side (e.g., a second opposing side, a second lateral side, etc.) of the first heat generation elements 310 and / or the second heat generation elements 3404894-9433-2367.1Atty. Dkt. No.: 86344674 in a longitudinal direction of the first heat generation elements 310 and / or the second heat generation elements 340. The heating length of the first heat generation elements 310 and / or the second heat generation elements 340 may correspond to a maximum width of wide printing mediums handled by the image forming apparatus (e.g., that the image forming apparatus forms printing images on, etc.). By way of example, the heating length of the first heat generation elements 310 and / or the second heat generation elements 340 may correspond to a width of A3 paper. The heating length of the first heat generation elements 310 and / or the second heat generation elements 340 may extend approximately 7.0 mm on each sides of the wide printing medium. When the heating length of the first heat generation elements 310 and / or the second heat generation elements 340 extends beyond the maximum width of the wide printing mediums, a risk of poor fusing of the printing images onto the wide printing mediums may be reduced. In some examples, the heating length of the first heat generation elements 310 and / or the second heat generation elements 340 may be between 305 mm to 316 mm, inclusive. In other examples, the heating length of the first heat generation elements 310 and / or the second heat generation elements 340 may be greater than 315 mm or less than 305 mm.

[0023] The heater structure 300 may have a heater width extending from a first side of the heater structure 300 to a second side of the heater structure 300 in a lateral direction of the heater structure 300. The heater width of the heater structure 300 may be greater than the nip width of the fixing apparatus 200 to prevent damage to the belt 226. For example, when the heater width of the heater structure 300 is greater than the nip width, scratching of the belt 226 at ends of the heater structure 300 may be prevented. In some examples, the heater width of the heater structure 300 may be between 8 mm to 10 mm, inclusive. In other examples, the heater width of the heater structure 300 may be greater than 10 mm or less than 8 mm.

[0024] The heater structure 300 may have a heating width extending from a first outer side (e.g., a first outer longitudinal side, etc.) of a first of an outermost of the first heat generation elements 310 or the second heat generation elements 340 to a second outer side (e.g., a second outer longitudinal side, etc.) of a second of the outermost of the first heat generation elements 310 or the second heat generation elements 340. By way of example, when the second heat generation elements 340 are arranged between the first heat generation elements 310, the heating width may extend from a first outer side of a first of the first heat generation elements 310 to a second outer side of a second of the first heat generation elements 310. By way of4894-9433-2367.1Atty. Dkt. No.: 86344674 another example, when the first heat generation elements 310 are arranged between the second heat generation elements 340, the heating width may extend from a first outer side of a first of the second heat generation elements 340 to a second outer side of a second of the second heat generation elements 340. The heating width may be smaller than the nip width of the fixing apparatus 200 to allow for the heat generated by the first heat generation elements 310 and / or the second heat generation elements 340 to be transferred to the belt 226. In some examples, the heating width of the heater structure 300 may be between 6.4 mm to 7.0 mm, inclusive. In other examples, the heating width is less than 6.4 mm or greater than 7.0 mm.

[0025] According to the example shown in FIG. 3, the second heat generation elements 340 are arranged between the first heat generation elements 310. By way of example, the first heat generation element 310a may be positioned at a first longitudinal side of the heater structure 300, the opposite first heat generation element 310b may be positioned at a second longitudinal side of the heater structure 300, the second longitudinal side opposing the first longitudinal side, the second heat generation element 340a may be positioned adjacent to the first heat generation element 310a and between the first heat generation element 310a and the opposite first heat generation element 310b, and the opposite second heat generation element 340b may be positioned adjacent to the opposite first heat generation element 310b and between the first heat generation element 310a and the opposite first heat generation element 310b.

[0026] The heater structure 300 may include a plurality of wires 380 (e.g., electrical conduits, etc.) electrically coupled to each of the first heat generation elements 310 and the second heat generation elements 340. The wires 380 may be electrically coupled to an electrical power source (e.g., a battery, an electrical inlet, etc.) of the image forming apparatus such that the wires 380 may supply electrical power (e.g., electricity, etc.) to the first heat generation elements 310 and the second heat generation elements 340. The first heat generation elements 310 and the second heat generation elements 340 may receive the electrical power from the electrical power source via the wires 380 and generate heat using the electrical power received from the electrical power source. By way of example, the first heat generation elements 310 and the second heat generation elements 340 may receive the electrical power from the wires 380. The electrical power may pass through components of the first heat generation elements 310 and the second heat generation elements 340 with a high electrical resistance, which causes the components to impede the flow of the electrical power through the first heat4894-9433-2367.1Atty. Dkt. No.: 86344674 generation elements 310 and the second heat generation elements 340, which results in the components of the first heat generation elements 310 and the second heat generation elements 340 generating and emitting heat. In other examples, the heater structure 300 may not include the wires 380 (e.g., when the heater structure 300 is not an electrical heater structure, when the second heat generation elements 340 and / or the first heat generation elements 310 do not utilize electrical power to generate heat, etc.).

[0027] According to the example shown in FIG. 3, the wires 380 include a first wire 382 electrically coupled to a first end of the first heat generation element 310a, a second wire 384 electrically coupled to a first end of the second heat generation element 340a, a third wire 386 electrically coupled to a second end of the first heat generation element 310a and a second end of the opposite first heat generation element 310b, a fourth wire 388 electrically coupled to a second end of the second heat generation element 340a and a first end of the opposite second heat generation element 340b, and a fifth wire 390 electrically coupled to a first end of the opposite first heat generation element 310b. The first wire 382, the second wire 384, and the fifth wire 390 may be electrically coupled the electrical power source of the image forming apparatus. When the electrical power source provides the electrical power to the first heat generation elements 310, the electrical power may pass through the first wire 382, through the first heat generation element 310a, through the third wire 386, through the opposite first heat generation element 310b, and through the fifth wire 390 to return to the electrical power source. When the electrical power source provides the electrical power to the second heat generation elements 340, the electrical power may pass through the second wire 384, through the second heat generation element 340a, through the fourth wire 388, through the opposite second heat generation element 340b, and through the fifth wire 390 to return to the electrical power source. Since the first wire 382 and the second wire 384 may be supplied with electrical power separately, the electrical power may be separately supplied to the first heat generation elements 310 and the second heat generation elements 340, allowing for the second heat generation elements 340 to generate heat separately from the first heat generation elements 310 and for the first heat generation elements 310 to generate heat separately from the second heat generation elements 340.

[0028] The first heat generation elements 310 and the second heat generation elements 340 may define gaps 302 (e.g., spaces, etc.) positioned between the first heat generation elements 310 and the second heat generation elements 340. The gaps 302 may block any current that4894-9433-2367.1Atty. Dkt. No.: 86344674 may occur between the first heat generation elements 310 and the second heat generation elements 340. By way of example, the first heat generation element 310a and the second heat generation element 340a may define a first gaps 302a positioned between the first heat generation element 310a and the second heat generation element 340a, the second heat generation element 340a and the opposite second heat generation element 340b may define a second gaps 302b positioned between the second heat generation element 340a and the opposite second heat generation element 340b, and the opposite first heat generation element 310b and the opposite second heat generation element 340b may define a third gaps 302c positioned between the opposite first heat generation element 310b and the opposite second heat generation element 340b. In some examples, the gaps 302 can be filled with a material that does not allow current to flow, blocking the current flowing across the gaps 302. By way of example, when the first heat generation element 310a generates heat and the second heat generation element 340a does not generate heat, the material of the gaps 302 prevents the current flowing from the first heat generation element 310a from flowing to the second heat generation element 340a, thereby preventing heat from being generated in 340a.

[0029] According to the example shown in FIG. 3, the wires 380 further define the gaps 302 positioned between the wires 380. By way of example, the first wire 382 and the second wire 384 may define a fourth gap 302d positioned between the first wire 382 and the second wire 384, the third wire 386 and the fourth wire 388 may define fifth gap 302e positioned between the third wire 386 and the fourth wire 388, and the second wire 384 and the fifth wire 390 may define a sixth gap 302f positioned between the second wire 384 and the fifth wire 390. In some examples, the gaps 302 defined by the wires 380 may be extensions of the gaps 302 defined by the first heat generation elements 310 and the second heat generation elements 340. For example, the sixth gap 302f may be an extension of the second gap 302b, the fifth gap 302e may be an extension of the first gap 302a and the third gap 302c, and the fourth gap 302d may be an extension of the first gap 302a. In other examples, the gaps 302 defined by the wires 380 may be separate from the gaps 302 defined by the first heat generation elements 310 and the second heat generation elements 340. In some examples, the gaps 302 may be filled with a material with a low conductivity (e.g., a lower conductivity than the wires 380, a lower conductivity than the second heat generation elements 340 and / or the first heat generation elements 310, etc.) to limit an amount of electrical power that is transferred across the gaps 302. By way of example, when the first wire 382 is supplying electrical power to the first heat generation element 310a and the second wire 384 is not supplying electrical power4894-9433-2367.1Atty. Dkt. No.: 86344674 to the second heat generation element 340a, the material in the gaps 302 positioned between the first wire 382 and the second wire 384 may limit an amount of the electrical power in the first wire 382 that is transferred to the first wire 382.

[0030] The first heat generation elements 310 may include first main heating areas 312 (e.g., first heating portions, middle heating portions, etc.) in a middle portion of the first heat generation elements 310 along a longitudinal direction of the first heat generation elements 310. For example, the first heat generation element 310a may include a first main heating area 312a and the opposite first heat generation element 310b may include an opposite first main heating area 312b. By way of example, the first main heating areas 312 may be positioned between a first end of the first heat generation elements 310 at a first side of the first heat generation elements 310 and a second end portion of the first heat generation elements 310 at a second side of the first heat generation elements 310, the second side opposing the first side. By way of another example, the first main heating area 312a may be positioned between a first portion of the first heat generation element 310a coupled to the first wire 382 and a second portion of the first heat generation element 310a coupled to the third wire 386.

[0031] The first main heating areas 312 may have a length LMHAI along the longitudinal direction of the first heat generation elements 310. The length LMHAI may correspond to a maximum width of printing images to be formed on narrow printing mediums handled by the image forming apparatus (e.g., that the image forming apparatus forms printing images on, etc.). By way of example, the length LMHAI may correspond to a width of A4 / Letter Short Edge Feeding (SEF) paper. The length LMHAI may extend approximately 1.0 mm beyond the maximum width of the printing images to be formed on the narrow printing mediums to reflect a margin of 1.0 mm on each of the sides of the printing image. When the length LMHAI extends beyond the maximum width of the printing images to be formed on the narrow printing mediums, a risk of poor fusing of the printing images onto the narrow printing mediums may be reduced. In some examples, the length LMHAI of the first main heating areas 312 may be between 200 mm to 210 mm, inclusive. In other examples, the length LMHAI of the first main heating areas 312 may be greater than 210 mm or less than 210 mm. The first main heating areas 312 may have a width WMHAI along a lateral direction (e.g., perpendicular to the longitudinal direction, etc.) of the first heat generation elements 310. In some examples, the width WMHAI of the first main heating areas 312 may be between 0.7 mm to 1.3 mm,4894-9433-2367.1Atty. Dkt. No.: 86344674 inclusive. In other examples, the width WMHAI of the first main heating areas 312 may be greater than 1.3 mm or less than 0.7 mm. There may be a distance DMHAI between the first main heating area 312a of the first heat generation element 310a and the opposite first main heating area 312b of the opposite first heat generation element 310b (e.g., the distance DMHAI between the first main heating areas 312, etc.). In some examples, the distance DMHAI may be between 2.5 mm and 3.5 mm. In other examples, the distance DMHAI may be less than 2.5 mm or greater than 3.5 mm. When the second heat generation elements 340 are arranged between the first heat generation elements 310, there may be a distance Doi between the first main heating areas 312 and the sides of the heater structure 300 (e.g., the longitudinal sides of the heater structure 300.

[0032] The first heat generation elements 310 may include one or more first auxiliary heating areas 314 (e.g., first peripheral heating areas heating portion, etc.). For example, the first heat generation element 310a may include one or more first auxiliary heating areas 314a and the opposite first heat generation element 310b may include one or more opposite first auxiliary heating areas 314b. The first auxiliary heating areas 314 may be operated at a different temperature than the first main heating areas 312. According to the example shown in FIG. 3, the first auxiliary heating areas 314 are located in side portions of the first heat generation elements 310 along the longitudinal direction of the first heat generation elements 310 such the first main heating areas 312 are positioned between the first auxiliary heating areas 314. The first auxiliary heating areas 314a may be on the first side and the second side of the first heat generation element 310a and the opposite first auxiliary heating areas 314b may be on the first side and the second side of the opposite first heat generation element 310b. By way of example, a first of the first auxiliary heating areas 314a may be positioned at a first end of the first auxiliary heating areas 314a at a first side of the first auxiliary heating areas 314a and a second of the first auxiliary heating areas 314a’ may be positioned at a second end portion of the first heat generation element 310a at a second side of the first heat generation element 310a, the second side opposing the first side, such that the first main heating area 312a is positioned between the first auxiliary heating areas 314a. By way of another example, a first of the opposite first auxiliary heating areas 314b may be coupled to the third wire 386, a second of the opposite first auxiliary heating areas 314b’ may be coupled to the fifth wire 390, and the opposite first main heating area 312b may be positioned between the first of the opposite first auxiliary heating areas 314b and the second of the opposite first auxiliary heating areas 314b’.4894-9433-2367.1Atty. Dkt. No.: 86344674

[0033] The first auxiliary heating areas 314 may have a length LAHAI along the longitudinal direction of the first heat generation elements 310. The length LAHAI of the first auxiliary heating areas 314 may be less than the length LMHAI of the first main heating areas 312. In some examples, the length LAHAI of the first auxiliary heating areas 314 may be between 40 mm to 60 mm, inclusive. In other examples, the length LAHAI of the first auxiliary heating areas 314 may be greater than 60 mm or less than 40 mm. In some examples, the first auxiliary heating areas 314 may have a width WAHAI along the lateral direction of the first heat generation elements 310. The width WAHAI of the first auxiliary heating areas 314 may be greater than the width WMHAI of the first main heating areas 312. The width WAHAI of the first auxiliary heating areas 314 being greater than the width WMHAI of the first main heating areas 312 may cause the temperature of first auxiliary heating areas 314 to be lower than the temperature of the first main heating areas 312. For example, if a first current is passed through the first heat generation elements 310, the first main heating areas 312 may have a higher resistance and thus generate more heat than the first auxiliary heating areas 314 due to the width WAHAI of the first auxiliary heating areas 314 being greater than the width WMHAI of the first main heating areas 312. In some examples, the width WAHAI of the first auxiliary heating areas 314 may be between 1.6 mm to 2.2 mm, inclusive. In other examples, the width WAHAI of the first auxiliary heating areas 314 may be greater than 2.2 mm or less than 1.6 mm. In some examples, a first difference between the width WAHAI of the first auxiliary heating areas 314 and the width WMHAI may be between 0.5 mm and 0.9 mm, inclusive. In other examples, the first difference between the width WAHAI of the first auxiliary heating areas 314 and the width WMHAI may be greater than 0.5 mm or less than 0.9 mm. In some examples, a first ratio between the width WAHAI of the first auxiliary heating areas 314 and the width WMHAI may be greater than 1.3. For example, when the first ratio between the width WAHAI of the first auxiliary heating areas 314 and the width WMHAI is greater than 1.3, there may be a reduction in risk of overheating along the sides of the belt 226 compared to when the first ratio between the width WAHAI of the first auxiliary heating areas 314 and the width WMHAI is less than 1.3.

[0034] According to the example shown in FIG. 3, the first main heating areas 312 are first recessed portions of the first heat generation elements 310 that define first recesses 316 of the first heat generation elements 310. By way of example, the first recesses 316 may extend into the first heat generation elements 310 proximate the first main heating areas 312. The first main heating area 312a and the first auxiliary heating areas 314a cooperatively define first4894-9433-2367.1Atty. Dkt. No.: 86344674 recess 316a and the opposite first main heating area 312b and the opposite first auxiliary heating areas 314b cooperatively define opposite first recess 316b. The first recesses 316 extend from the first main heating areas 312 to an edge (e.g., a peripheral edge, etc.) of the first auxiliary heating areas 314. According to the example shown in FIG. 3, the first recesses 316 are oriented in opposite directions away from each other based on the first main heating areas 312 being oriented in opposite directions towards each other. The first main heating areas 312 may be located toward an outside of the heater structure 300. By way of example, the first recess 316a may extend outward from the first main heating area 312a to an outer edge of the first auxiliary heating areas 314a away from the center of the heater structure 300 and the opposite first recess 316b may extend outward from the opposite first main heating area 312b to an outer edge of the opposite first auxiliary heating areas 314b away from the center of the heater structure 300. In other examples, the first recesses 316 may be oriented in opposite directions towards each other based on the first main heating areas 312 being oriented in opposite directions away from each other. In still other examples, the first recesses 316 may be oriented in the same direction based on the first main heating areas 312 being oriented in the same direction.

[0035] The first heat generation elements 310 may include first transition areas 318 positioned between the first auxiliary heating areas 314 and the first main heating areas 312. For example, the first heat generation element 310a may include first transition areas 318a positioned between the first auxiliary heating areas 314a and the first main heating area 312a and the opposite first heat generation element 310b may include opposite first transition areas 318b positioned between the opposite first auxiliary heating areas 314b and the opposite first main heating area 312b. The first transition areas 318 may transition widths of the first heat generation elements 310 between the WMHAI of the first main heating areas 312 and the width WAHAI of the first auxiliary heating areas 314. The first transition areas 318 may increase in width from first sides of the first transition areas 318 adjacent to the first main heating areas 312 to second sides of the first transition areas 318 adjacent to the first auxiliary heating areas 314. By way of example, a first of the first transition areas 318a may be positioned between the first main heating area 312a and the first of the first auxiliary heating areas 314a, a second of the first transition areas 318a’ may be positioned between the first main heating area 312a and the second of the first auxiliary heating areas 314a’, a first of the opposite first transition areas 318b may be positioned between the opposite first main heating area 312b and the first of the opposite first auxiliary heating areas 314b, and a second of the opposite first transition4894-9433-2367.1Atty. Dkt. No.: 86344674 areas 318b’ may be positioned between the opposite first main heating area 312b and the second of the opposite first auxiliary heating areas 314b’. By way of another example, the first transition areas 318 may cause a width of the first heat generation elements 310 to be increasing at ends (e.g., outer ends, etc.) of the first main heating areas 312 and / or decreasing at an end (e.g., a first end, an inner end, etc.) of the first auxiliary heating areas 314. The first transition areas 318a may have first widths substantially equal to the width WAHAI of the first auxiliary heating areas 314a at first sides of the first transition areas 318a adjacent to the first auxiliary heating areas 314a and second widths substantially equal to the width WMHAI of the first main heating area 312a at second sides of the first transition areas 318a adjacent to the first main heating area 312a. In some examples, the distance between the first auxiliary heating areas 314a of the first heat generation element 310a and the opposite first auxiliary heating areas 314b of the opposite first heat generation element 310b may be equal to the distance DMHAI between the first main heating area 312a of the first heat generation element 310a and the opposite first main heating area 312b of the opposite first heat generation element 310b. In some examples, the first transition areas 318 may linearly increase the width of the first heat generation elements 310 from the first main heating areas 312 to the first auxiliary heating areas 314.

[0036] The first transition areas 318 may have a length LTAI along the longitudinal direction of the first heat generation elements 310. The length LTAI of the first transition areas 318 may reduce thermal stresses in the first heat generation elements 310 that could result from the difference between the WMHAI of the first main heating areas 312 and the width WAHAI of the first auxiliary heating areas 314. In some examples, the length LTAI may be between 4 mm and 6 mm, inclusive. In other examples, the length LTAI may be greater than 6 mm or less than 4 mm. As shown in FIG. 3, the heating length of the first heat generation elements 310 may be equal to a sum of the length LMHAI of the first main heating areas 312, two of the length LTAI of the first transition areas 318, and two of the length LAHAI of the extended portions 354.

[0037] The first heat generation elements 310 may include first edges 320 on first longitudinal sides of the first heat generation elements 310. For example, the first heat generation element 310a may include a first edge 320a (e.g., a first line, a third line, etc.) on a first longitudinal side of the first heat generation element 310a and the opposite first heat generation element 310b may include an opposite first edge 320b on an opposite first4894-9433-2367.1Atty. Dkt. No.: 86344674 longitudinal side of the opposite first heat generation element 310b. The first edge 320 may extend along the first main heating areas 312 and the first auxiliary heating areas 314. According to the example shown in FIG. 3, the first edges 320 are on an inner longitudinal side (e.g., an inside, an inside longitudinal side, etc.) of the first heat generation elements 310. The first edges 320 may be a first straight edge that extends straight from a first end of the first heat generation elements 310 to a second end of the first heat generation elements 310.

[0038] The first heat generation elements 310 may include first deviated edges 322 on second longitudinal sides of the first heat generation elements 310 opposing the first longitudinal sides of the first heat generation elements 310. For example, the first heat generation element 310a may include a first deviated edge 322a (e.g., a second line, etc.) on a second longitudinal side of the first heat generation element 310a opposing the first longitudinal side of the first heat generation element 310a and the opposite first heat generation element 310b may include an opposite first deviated edge 322b on an opposite second longitudinal side of the opposite first heat generation element 310b opposing the opposite first longitudinal side of the opposite first heat generation element 310b. The first deviated edges 322 may extend along the first main heating areas 312 and the first auxiliary heating areas 314 and may define the first recesses 316. A length of the first deviated edges 322 may be greater than a length of the first edges 320. According to the example shown in FIG. 3, the first deviated edges 322 are on an outer longitudinal side (e.g., an outside, an outside longitudinal side, etc.) of the first heat generation elements 310. The first deviated edges 322 may not extend straight from the first end of the first heat generation elements 310 to the second end of the first heat generation elements 310.

[0039] The second heat generation elements 340 may include second main heating areas 342 on first sides and second sides respectively of the second heat generation elements 340 along a longitudinal direction of the second heat generation elements 340. For example, the second heat generation element 340a may include second main heating areas 342a (e.g., a first heating portion, a middle heating portion, etc.) on first sides and second sides respectively of the second heat generation element 340a and the opposite second heat generation element 340b may include opposite second main heating areas 342b on first sides and second sides respectively of the opposite second heat generation element 340b. According to the example shown in FIG. 3, the second heat generation element 340a includes a first of the second main heating areas 342a on the first side of the second heat generation element 340a, a second of4894-9433-2367.1Atty. Dkt. No.: 86344674 the second main heating areas 342a’ on the second side of the second heat generation element 340a, a first of the opposite second main heating areas 342b on the first side of the opposite second heat generation element 340b, and a second of the opposite second main heating areas 342b’ on the second side of the opposite second heat generation element 340b. By way of example, the second main heating areas 342 may be positioned at a first end of the second heat generation elements 340 at a first side of the second heat generation elements 340 and at a second end of the second heat generation elements 340 at a second side of the second heat generation elements 340, the second side opposing the first side. By way of another example, a first of the second main heating areas 342a of the second heat generation element 340a may be coupled to the second wire 384 and a second of the second main heating areas 342a of the second heat generation element 340a may be coupled to the fourth wire 388.

[0040] The second main heating areas 342 may have a length LMHA2 along the longitudinal direction of the second heat generation elements 340. A sum of the lengths LMHA2 of the second main heating areas 342 may correspond to or become longer than a difference between a maximum width of narrow printing medium handled by the image forming apparatus and a maximum width of wide printing mediums handled by the image forming apparatus. By way of example, the sum of the lengths LMHA2 of the second main heating areas 342 may correspond to or be longer than a difference between a first width of A4 / Letter SEF paper and a second width of A4 LEF paper. In some examples, the length LMHA2 of the second main heating areas 342 may be between 50 mm to 60 mm, inclusive. In various examples, the length LMHA2 of the second main heating areas 342 may be equal to the length LAHAI of the first auxiliary heating areas 314. In other examples, the length LMHA2 of the second main heating areas 342 may be greater than 60 mm or less than 50 mm. The second main heating areas 342 may have a width WMHA2 along a lateral direction (e.g., perpendicular to the longitudinal direction, etc.) of the second heat generation elements 340. In some examples, the width WMHA2 of the second main heating areas 342 may be between 0.4 mm to 0.8 mm, inclusive. In other examples, the width WMHA2 of the second main heating areas 342 may be greater than 0.8 mm or less than 0.4 mm. There may be a distance DMHA2 between the second main heating areas 342a of the second heat generation element 340a and the opposite second main heating areas 342b of the opposite second heat generation element 340b (e.g., the distance DMHA2 between the second main heating areas 342, etc.). In some examples, the distance DMHA2 may be between 0.8 mm and 1.2 mm, inclusive. In other examples, the distance DMHA2 is less than 0.8 mm or greater than 1.2 mm.4894-9433-2367.1Atty. Dkt. No.: 86344674

[0041] In some examples, there may be a distance DMHAS between the first heat generation elements 310 and corresponding of the second heat generation elements 340 adjacent to the first heat generation elements 310. By way of example, there may be the distance DMHAS between the first heat generation element 310a and the second heat generation element 340a and the opposite first heat generation element 310b and the opposite second heat generation element 340b. The gaps 302 extending along the distance DMHAS may be filled with an insulation to insulate the first heat generation elements 310 from the second heat generation elements 340. The distance DMHA3 may be greater than a minimum distance 0.1 mm to prevent a risk of insulation breakdown between the first heat generation elements 310 and the corresponding of the second heat generation elements 340. The distance DMHAS may be less than a minimum distance 1.0 mm to reduce a temperature deviation across the heater width of the heater structure 300. In some examples, the distance DMHAS may be between 0.1 mm to 2.0 mm, inclusive. In some examples, the distance DMHA3 may be between 0.2 mm to 0.8 mm, inclusive. In other example, the distance DMHA3 may be less than 0.2 mm or greater than 0.6 mm.

[0042] The second heat generation elements 340 may include second auxiliary heating areas 344. For example, the second heat generation element 340a may include a second auxiliary heating area 344a (e.g., a middle heating portion, etc.) and the opposite second heat generation element 340b may include an opposite second auxiliary heating area 344b. According to the example shown in FIG. 3, the second auxiliary heating areas 344 are located in a middle portion of the second heat generation elements 340 along the longitudinal direction of the second heat generation elements 340 such that the second auxiliary heating areas 344 are positioned between the second main heating areas 342. By way of example, a first of the second main heating areas 342a may be positioned at a first end of the second heat generation element 340a at a first side of the second heat generation element 340a, a second of the second main heating areas 342a may be positioned at a second end of the second heat generation element 340a at a second side of the second heat generation element 340a, and the second auxiliary heating area 344a may be positioned between the first of the second main heating areas 342a and the second of the second main heating areas 342a. By way of another example, a first of the second main heating areas 342 at the first end may be coupled to the second wire 384 or the fifth wire 390 , a second of the opposite second main heating areas 342b at the second end may be coupled the fourth wire 388, and the opposite second auxiliary heating4894-9433-2367.1Atty. Dkt. No.: 86344674 area 344b may be positioned between the first of the opposite second main heating areas 342b and the second of the opposite second main heating areas 342b.

[0043] In some examples, the second auxiliary heating areas 344 may have a length LAHA2 along the longitudinal direction of the second heat generation elements 340. The length LAHA2 of the second auxiliary heating areas 344 may be greater than the LMHA2 of the second main heating areas 342. In some examples, the length LAHA2 of the second auxiliary heating areas 344 may be between 190 mm to 220 mm, inclusive. In other examples, the length LAHA2 of the second auxiliary heating areas 344 may be greater than 220 mm or less than 190 mm. In various examples, the length LAHA2 of the second auxiliary heating areas 344 may be equal to the length LMHAI of the first main heating areas 312. The second auxiliary heating areas 344 may have a width WAHA2 along the lateral direction of the second heat generation elements 340. The width WAHA2 of the second auxiliary heating areas 344 may be greater than the width WMHA2 of the second main heating areas 342 such that a width of the second heat generation elements 340 at each side of the second heat generation elements 340 may be less than the width WAHA2 of the second auxiliary heating areas 344. The width WAHA2 of the second auxiliary heating areas 344 being greater than the width WMHA2 of the second main heating areas 342 may cause the temperature of second auxiliary heating areas 344 to be lower than the temperature of the second main heating areas 342. For example, if a second current is passed through the second heat generation elements 340, the second main heating areas 342 may have a higher resistance and thus generate more heat than the second auxiliary heating areas 344 due to the width WAHA2 of the second auxiliary heating areas 344 being greater than the width WMHA2 of the second main heating areas 342. In some examples, the width WAHA2 of the second auxiliary heating areas 344 may be between 0.7 mm to 1.2 mm, inclusive. In other examples, the width WAHA2 of the second auxiliary heating areas 344 may be greater than 1.2 mm or less than 0.7 mm. There may be a distance DAHA2 between the second auxiliary heating area 344a of the second heat generation element 340a and the opposite second auxiliary heating area 344b of the opposite second heat generation element 340b (e.g., the distance DAHA2 between the second auxiliary heating areas 344, etc.). In some examples, the distance DAHA2 between the second auxiliary heating area 344a of the second heat generation element 340a and the opposite second auxiliary heating area 344b of the opposite second heat generation element 340b may be less than the distance DMHA2 between the second main heating areas 342. The gaps 302 extending along the distance DAHA2 may be filled with an insulation to insulate the second heat generation element 340a from the opposite second heat4894-9433-2367.1Atty. Dkt. No.: 86344674 generation element 340b. The distance DAHA2 may be greater than a minimum distance 0.1 mm to prevent a risk of insulation breakdown between the second heat generation element 340a and the opposite second heat generation element 340b. The distance DAHA2 may be less than a minimum distance 1.0 mm to reduce a temperature deviation across the heater width of the heater structure 300. In some examples, the distance DAHA2 may be between 0.2 mm and 0.6 mm, inclusive. In other example, the distance DAHA2 may be less than 0.2 mm or greater than 0.6 mm.

[0044] According to the example shown in FIG. 3, the second main heating areas 342 are second recessed portions of the second heat generation elements 340 that define second recesses 346 of the second heat generation elements 340. By way of example, the second recesses 346 may extend into the second heat generation elements 340 proximate the second main heating areas 342. For example, the second main heating areas 342a and the second auxiliary heating area 344a may cooperatively define a first of the second recesses 346a at the first end of the second heat generation element 340a and a second of the second recesses 346a’ at the second end of the second heat generation element 340a. The opposite second main heating areas 342b and the opposite second auxiliary heating area 344b may cooperatively define a first of the opposite second recesses 346b at the first end of the opposite second heat generation element 340b and a second of the opposite second recesses 346b’ at the second end of the opposite second heat generation element 340b. The second recesses 346 may extend from the second main heating areas 342 to an edge (e.g., a peripheral edge, etc.) of the second auxiliary heating areas 344. According to the example shown in FIG. 3, the second recesses 346 are oriented in opposite directions towards each other (e.g., facing each other, etc.) based on the second main heating areas 342 being oriented in opposite directions away from each other. The second main heating areas 342 may be located to face each other (e.g., located toward a center of the heater structure 300, etc.). By way of example, the second recesses 346a may extend inward from the second main heating areas 342a to an inner edge of the second auxiliary heating area 344a toward a center of the heater structure 300 and the opposite second recesses 346b may extend inward from the opposite second main heating areas 342b to an inner edge of the opposite second auxiliary heating area 344b toward the center of the heater structure 300. In other examples, the second recesses 346 may be oriented in opposite directions toward each other based on the second main heating areas 342 being oriented in opposite directions away from each other. In still other examples, the second4894-9433-2367.1Atty. Dkt. No.: 86344674 recesses 346 may be oriented in the same direction based on the second main heating areas 342 being oriented in the same direction.

[0045] According to the example shown in FIG. 3, the first recesses 316 of the first heat generation elements 310 and corresponding of the second recesses 346 of the second heat generation elements 340 adjacent to the first heat generation elements 310 are oriented in opposite directions away from each other based on the first auxiliary heating areas 314 of the first heat generation elements 310 and corresponding of the second auxiliary heating areas 344 of the second heat generation elements 340 adjacent to the first heat generation elements 310 being oriented in opposite directions towards each other. By way of example, the first auxiliary heating areas 314a of the first heat generation element 310a may correspond to the second auxiliary heating area 344a of the second heat generation element 340a based on the first heat generation element 310a being positioned adjacent to the second heat generation element 340a. The first recess 316a may extend outward from the first main heating area 312a to an outer edge of the first auxiliary heating areas 314a away from the center of the heater structure 300 and second recesses 346a corresponding to the first recess 316a may extend inward from the second main heating areas 342a to an inner edge of the second auxiliary heating area 344a toward the center of the heater structure 300. By way of another example, the opposite first main heating area 312b of the opposite first heat generation element 310b may correspond to the opposite second main heating areas 342b of the opposite second heat generation element 340b based on the opposite first heat generation element 310b being positioned adjacent to the opposite second heat generation element 340b. The first main heating area 312a and the corresponding second main heating areas 342a may be oriented in opposite directions based on the first recess 316a defined by the first main heating area 312a extending outward from the first main heating area 312a away from a center of the heater structure 300 and the opposite second recesses 346a defined by the second main heating areas 342a extending inward from the second main heating areas 342a toward the center of the heater structure 300.

[0046] The second heat generation elements 340 may include second transition areas 348 positioned between the second auxiliary heating areas 344 and the second main heating areas 342. For example, the second heat generation element 340a may include second transition areas 348a positioned between the second auxiliary heating area 344a and the second main heating areas 342a and the opposite second heat generation element 340b may include4894-9433-2367.1Atty. Dkt. No.: 86344674 opposite second transition areas 348b positioned between the opposite second auxiliary heating area 344b and the second main heating areas 342a. The second transition areas 348 may transition widths of the second heat generation elements 340 between the WMHA2 of the second main heating areas 342 and the width WAHA2 of the second auxiliary heating areas 344. The second transition areas 348 may decrease in width from first sides of the second transition areas 348 adjacent to the second auxiliary heating areas 344 to second sides of the second transition areas 348 adjacent to the second main heating areas 342. By way of example, a first of the second transition areas 348a may be positioned between the first of the second main heating areas 342a and the second auxiliary heating area 344a, a second of the second transition areas 348a’ may be positioned between the second of the second main heating areas 342a’ and the second auxiliary heating area 344a, a first of the opposite second transition areas 348b may be positioned between the first of the opposite second main heating areas 342b and the opposite second auxiliary heating area 344b, and a second of the opposite second transition areas 348b’ may be positioned between the second of the opposite second main heating areas 342b’ and the opposite second auxiliary heating area 344b. The second transition areas 348a may have first widths substantially equal to the width WAHA2 of the second auxiliary heating area 344a at first sides of the second transition areas 348a adjacent to the second auxiliary heating area 344a and second widths substantially equal to the width WMHA2 of the second main heating areas 342a at second sides of the second transition areas 348a adjacent to the second main heating areas 342a. By way of another example, the second transition areas 348 may cause a width of the second heat generation elements 340 to be decreasing at ends (e.g., outer ends, etc.) of the second auxiliary heating areas 344 and / or increasing at an end (e.g., a first end, an inner end, etc.) of the second main heating areas 342. In some examples, the second transition areas 348 may linearly increase the width of the second heat generation elements 340 from the second main heating areas 342 to the second auxiliary heating areas 344.

[0047] The second transition areas 348 may have a length LTA2 along the longitudinal direction of the second heat generation elements 340. The length LTA2 of the second transition areas 348 may reduce thermal stresses in the second heat generation elements 340 that could result from the difference between the WMHA2 of the second main heating areas 342 and the width WAHA2 of the second auxiliary heating areas 344. In some examples, the length LTA2 may be between 5 mm and 6 mm, inclusive. In other examples, the length LTA2 may be greater than 6 mm or less than 5 mm. In some examples, the heating length of the second heat4894-9433-2367.1Atty. Dkt. No.: 86344674 generation elements 340 may be equal to a sum of the length LAHA2 of the second auxiliary heating areas 344, two of the length LTA2 of the second transition areas 348, and two of the length LMHA2 of the second main heating areas 342.

[0048] The second heat generation elements 340 may include a second edge 350 on first longitudinal sides of the second heat generation elements 340. For example, the second heat generation element 340a may include a second edge 350a (e.g., a second line, a third line etc.) on a first longitudinal side of the second heat generation element 340a and the opposite second heat generation element 340b may include an opposite second edge 350b on an opposite first longitudinal side of the opposite second heat generation element 340b. The second edges 350 may extend along the second main heating areas 342 and the second auxiliary heating areas 344. According to the example shown in FIG. 3, the second edges 350 are on an outer longitudinal side (e.g., an outside, an outside longitudinal side, etc.) of the second heat generation elements 340. The second edges 350 may be a second straight edge that extends straight from a first end of the second heat generation elements 340 to a second end of the second heat generation elements 340.

[0049] According to the example shown in FIG. 3, the first edges 320 of the first heat generation elements 310 are positioned to face the second edges 350 of adjacent of the second heat generation elements 340. By way of example, when the second heat generation element 340a is positioned adjacent to the first heat generation element 310a and the opposite second heat generation element 340b is positioned adjacent to the opposite first heat generation element 310b, the second edge 350a of the second heat generation element 340a is positioned to face the first edge 320a of the first heat generation element 310a, and the opposite second edge 350b of the opposite second heat generation element 340b is positioned to face the opposite first edge 320b of the opposite first heat generation element 310b. The second edges 350 may be positioned to face the first edges 320 when the second edges 350 are the closest portion of the second heat generation elements 340 to the first heat generation elements 310 and the first edges 320 are the closest portion of the first heat generation elements 310 to the second heat generation elements 340.

[0050] The second heat generation elements 340 may include second deviated edges 352 on second longitudinal sides of the second heat generation elements 340 opposing the first longitudinal sides of the second heat generation elements 340. For example, the second heat generation element 340a may include a second deviated edge 352a (e.g., a second line, a4894-9433-2367.1Atty. Dkt. No.: 86344674 fourth line, etc.) on a second longitudinal side of the second heat generation element 340a opposing the first longitudinal side of the second heat generation element 340a and the opposite second heat generation element 340b includes an opposite second deviated edge 352b on an opposite second longitudinal side of the opposite second heat generation element 340b opposing the opposite first longitudinal side of the opposite second heat generation element 340b. The second deviated edges 352 may extend along the second main heating areas 342 and the second auxiliary heating areas 344 and define the second recesses 346. A length of the second deviated edges 352 may be greater than a length of the second edge 350. According to the example shown in FIG. 3, the second deviated edges 352 are on an inner longitudinal side (e.g., an inside, an inside longitudinal side, etc.) of the second heat generation elements 340. The second deviated edges 352 may not extend straight from the first end of the second heat generation elements 340 to the second end of the second heat generation elements 340.

[0051] According to the example shown in FIG. 4, the heater structure 300 may include the first heat generation element 310a, the opposite first heat generation element 310b, the second heat generation element 340a, the opposite second heat generation element 340b, and the wires 380 coupled to each of the first heat generation elements 310 and the second heat generation elements 340. According to the example shown in FIG. 4, the second heat generation elements 340 are arranged between the first heat generation elements 310. As shown in FIG. 4, the first heat generation elements 310 and the second heat generation elements 340 define the gaps 302 positioned between the first heat generation elements 310 and the second heat generation elements 340.

[0052] The wires 380 may include the first wire 382 electrically coupled to a first end of the first heat generation element 310a, the second wire 384 electrically coupled to a first end of the second heat generation element 340a, the third wire 386 electrically coupled to a second end of the first heat generation element 310a and a second end (opposite to the first end) of the opposite first heat generation element 310b, the fourth wire 388 electrically coupled to a second end of the second heat generation element 340a and a second end of the opposite second heat generation element 340b, and the fifth wire 390 electrically coupled to a first end of the opposite first heat generation element 310b and a first end of the opposite second heat generation element 340b. According to the example shown in FIG. 4, the wires 380 further define the gaps 302 positioned between the wires 380.4894-9433-2367.1Atty. Dkt. No.: 86344674

[0053] The first heat generation elements 310 may include the first main heating areas 312, the first auxiliary heating areas 314, the first transition areas 318, the first edges 320, and the first deviated edges 322. The first main heating areas 312 and the first auxiliary heating areas 314 may cooperatively define the first recesses 316. According to the example shown in FIG. 4, the first recesses 316 are oriented in opposite directions away from each other based on the first main heating areas 312 being oriented in opposite directions towards each other. The first main heating areas 312 may have the length LMHAI along the longitudinal direction of the first heat generation elements 310, the width WMHAI along the lateral direction of the first heat generation elements 310, and there may be the distance DMHAI between the first main heating area 312a of the first heat generation element 310a and the opposite first main heating area 312b of the opposite first heat generation element 310b. The first auxiliary heating areas 314 may have the length LAHAI along the longitudinal direction of the first heat generation elements 310 and the width WAHAI along the lateral direction of the first heat generation elements 310. The first transition areas 318 may have the length LTAI along the longitudinal direction of the first heat generation elements 310. When the second heat generation elements 340 are arranged between the first heat generation elements 310, there may be the distance Doi between the first main heating areas 312 and the sides of the heater structure 300 (e.g., the longitudinal sides of the heater structure 300.

[0054] The second heat generation elements 340 may include the second main heating areas 342, the second auxiliary heating areas 344, the second transition areas 348, the second edge 350, and the second deviated edges 352. The second main heating areas 342 may have the length LMHA2 along the longitudinal direction of the second heat generation elements 340, the width WMHA2 along the lateral direction of the second heat generation elements 340, and there may be the distance DMHA2 between the second main heating areas 342a of the second heat generation element 340a and the opposite second main heating areas 342b of the opposite second heat generation element 340b. The second auxiliary heating areas 344 may have the length LAHA2 along the longitudinal direction of the second heat generation elements 340 and the width WAHA2 along the lateral direction of the second heat generation elements 340. The second transition areas 348 may have the length LTA2 along the longitudinal direction of the second heat generation elements 340. There may be the distance DMHAS between the first heat generation elements 310 and corresponding of the second heat generation elements 340 adjacent to the first heat generation elements 310.4894-9433-2367.1Atty. Dkt. No.: 86344674

[0055] The second heat generation elements 340 include one or more extended portions 354. For example, the second heat generation element 340a may include one or more extended portions 354a and the opposite second heat generation element 340b may include one or more opposite extended portions 354b. The extended portions 354 may be located in extended side portions of the second heat generation elements 340 along the longitudinal direction of the second heat generation elements 340 such that the second main heating areas 342 and the second auxiliary heating areas 344 are positioned between the extended portions 354. The extended portions 354a may be at a first end of the first side and a second end of the second side of the second heat generation element 340a and the opposite extended portions 354b may be at a first end of the first side and a second end of the second side of the opposite second heat generation element 340b. By way of example referring to FIG. 4, a first of the extended portions 354a may be positioned at the first end of the second heat generation element 340a and a second of the extended portions 354a’ may be positioned at the second end of the second heat generation element 340a, such that the second main heating areas 342a and the second auxiliary heating area 344a are positioned between the first of the extended portions 354a and the second of the extended portions 354a’. By way of an example, a first of the opposite extended portions 354b354a may be coupled to the second wire 384 at the first end, a second of the opposite extended portions 354b354a’ may be coupled to the fourth wire 388, and the second main heating areas 342a and the second auxiliary heating area 344a may be positioned between the first of the opposite extended portions 354b354a and the second of the extended portions 354a’. Similarly, the opposite second main heating areas 342b and the opposite second auxiliary heating area 344b of the opposite second heat generation element 340b may be positioned between a first of the opposite extended portions 354b and a second of the opposite extended portions 354b'.

[0056] The extended portions 354 may have a length LEP2 along the longitudinal direction of the second heat generation elements 340. The length LEP2 of the extended portions 354 may be less than the length LMHA2 of the second main heating areas 342 and is less than the length LAHA2 of the second auxiliary heating areas 344. In some examples, the length LEP2 of the extended portions 354 may be between 6 mm and 7 mm, inclusive. In other examples, the length LEP2 may be greater than 7 mm or less than 6 mm. In some examples, the extended portions 354 may have a width WEP2 along the lateral direction of the second heat generation elements 340. The width WEP2 of the extended portions 354 may be equal to the width WAHA2 of the second auxiliary heating areas 344. The width WEP2 may be greater than the width4894-9433-2367.1Atty. Dkt. No.: 86344674WMHA2 of the second main heating areas 342. In some examples, the width WEP2 of the extended portions 354 may be between 0.5 mm to 1.0 mm, inclusive. In other examples, the width WEP2 of the extended portions 354 may be greater than 1.0 mm or less than 0.5 mm.

[0057] The second heat generation elements 340 may include extension transition areas 356 positioned between the second main heating areas 342 and the extended portions 354. For example, the second heat generation element 340a may include extension transition areas 356a positioned between the second main heating areas 342a and the extended portions 354a and the opposite second heat generation element 340b may include opposite transition areas 356b positioned between the opposite second main heating areas 342b and the opposite extended portions 354b. The extension transition areas 356 may transition widths of the second heat generation elements 340 between the width WMHA2 of the second main heating areas 342 and the width WEP2 of the extended portions 354. The extension transition areas 356 may increase in width from first sides of the extension transition areas 356 adjacent to the second main heating areas 342 to second sides of the extension transition areas 356 adjacent to the extended portions 354. By way of example, a first of the extension transition areas 356a may be positioned between the first of the second main heating areas 342a and the first of the extended portions 354a, a second of the extension transition areas 356a’ may be positioned between the second of the second main heating areas 342a’ and the second of the extended portions 354a’, a first of the opposite transition areas 356b may be positioned between the first of the opposite second main heating areas 342b and the first of the opposite extended portions 354b, and a second of the opposite transition areas 356b’ may be positioned between the second of the opposite second main heating areas 342b’ and the second of the opposite extended portions 354b’. By way of another example, the extension transition areas 356 may cause a width of the second heat generation elements 340 to be increasing at an end (e.g., a second end, an outer end, etc.) of the second main heating areas 342 and / or decreasing at an end (e.g., a first end, an inner end, etc.) of the extended portions 354. The extension transition areas 356a may have first widths substantially equal to the width WMHA2 of the second main heating areas 342a at first sides of the second transition areas 348a adjacent to the second auxiliary heating area 344a and second widths substantially equal to the width WEP2 of the extended portions 354a at second sides of the extension transition areas 356a adjacent to the extended portions 354a. In some examples, the extended portions 354 may linearly increase the width of the second heat generation elements 340 from the second main heating areas 342 to the extended portions 354.4894-9433-2367.1Atty. Dkt. No.: 86344674

[0058] The extension transition areas 356 may have a length LETA2 along the longitudinal direction of the second heat generation elements 340. In some examples, the length LETA2may be between 5 mm and 6 mm, inclusive. In other examples, the length LETA2 may be greater than 6 mm or less than 5 mm. The heating length of the second heat generation elements 340 may be equal to a sum of the length LAHA2 of the second auxiliary heating areas 344, two of the length LTA2 of the second transition areas 348, two of the length LMHA2 of the second main heating areas 342, and two of the length LEP2 of the extended portions 354. The extension transition areas 356, the second main heating areas 342, the second transition areas 348, and the second auxiliary heating areas 344 may have a combined length LRPS along the longitudinal direction of the second heat generation elements 340. The combined length LRPS may correspond to a maximum width of the printing mediums handled by the image forming apparatus (e.g., the maximum width of the wide printing mediums handled by the image forming apparatus, etc.). For example, the combined length LRP3 may extend approximately 5.0 mm beyond the maximum width of the printing mediums handled by the image forming apparatus such that the extended portions 354 may be positioned outside of the maximum width of the printing mediums. When the combined length LRP3 extends beyond the maximum width of the printing mediums, a risk of poor fusing of the printing images onto the printing mediums may be reduced. In some examples, the combined length LRP3 may be between 300 mm and 310 mm, inclusive. In other examples, the combined length LRP3 may be greater than 310 mm or less than 300 mm.

[0059] According to the example shown in FIG. 4, the second main heating areas 342, the second auxiliary heating areas 344, and the extended portions 354 cooperatively define the second recesses 346 and the second recesses 346 are oriented in opposite directions towards each other based on the second main heating areas 342 being oriented in opposite directions away from each other. According to the example shown in FIG. 4, the second recesses 346 of the second heat generation elements 340 and corresponding of the first recesses 316 of the first heat generation elements 310 adjacent to the second heat generation elements 340 are oriented in opposite directions away from each other based on the second main heating areas 342 of the second heat generation elements 340 and corresponding of the first main heating areas 312 of the first heat generation elements 310 adjacent to the second heat generation elements 340 being oriented in opposite directions towards each other.4894-9433-2367.1Atty. Dkt. No.: 86344674

[0060] In the example shown in FIG. 5, the heater structure 300 includes the first heat generation element 310a, the opposite first heat generation element 310b, the second heat generation element 340a, and the opposite second heat generation element 340b. According to the example shown in FIG. 5, the first heat generation elements 310 are arranged between the second heat generation elements 340. The first heat generation elements 310 and the second heat generation elements 340 may define the gaps 302 positioned between the first heat generation elements 310 and the second heat generation elements 340.

[0061] The heater structure 300 may include the wires 380 coupled to each of the first heat generation elements 310 and the second heat generation elements 340. According to the example shown in FIG. 5, the wires 380 include the first wire 382 electrically coupled to a first end of the second heat generation element 340a, the second wire 384 electrically coupled to a first end of the first heat generation element 310a, the third wire 386 electrically coupled to a second end of the second heat generation element 340a and a first end of the opposite second heat generation element 340b, the fourth wire 388 electrically coupled to a second end of the first heat generation element 310a and a first end of the opposite first heat generation element 310b, and the fifth wire 390 electrically coupled to a second end of the opposite second heat generation element 340b and a second end of the opposite first heat generation element 310b. According to the example shown in FIG. 5, the wires 380 further define the gaps 302 positioned between the wires 380.

[0062] The first heat generation elements 310 may include the first main heating areas 312, the first auxiliary heating areas 314, the first transition areas 318, the first edges 320, and the first deviated edges 322. The first main heating areas 312 and the first auxiliary heating areas 314 may cooperatively define the first recesses 316. According to the example shown in FIG. 5, the first recesses 316 are oriented in opposite directions towards each other based on the first main heating areas 312 being oriented in opposite directions away from each other. The first main heating areas 312 may have the length LMHAI along the longitudinal direction of the first heat generation elements 310 and the width WMHAI along the lateral direction of the first heat generation elements 310. The first auxiliary heating areas 314 may have the length LAHAI along the longitudinal direction of the first heat generation elements 310 and the width WAHAI along the lateral direction of the first heat generation elements 310. There may be a distance DAHAI between the first auxiliary heating areas 314a of the first heat generation element 310a and the opposite first auxiliary heating areas 314b of the opposite first heat4894-9433-2367.1Atty. Dkt. No.: 86344674 generation element 310b (e.g., the distance DAHAI between the first auxiliary heating areas 314, etc.). In some examples, the distance DAHAI may be between 0.2 mm and 0.4 mm. In other examples, the distance DAHAI may be less than 0.2 mm or greater than 0.4 mm. The first transition areas 318 may have the length LTAI along the longitudinal direction of the first heat generation elements 310.

[0063] The second heat generation elements 340 may include the second main heating areas 342, the second auxiliary heating areas 344, the second transition areas 348, the second edge 350, and the second deviated edges 352. According to the example shown in FIG. 5, the second main heating areas 342 and the second auxiliary heating areas 344 cooperatively define the second recesses 346 and the second recesses 346 are oriented in opposite directions away from each other based on the second main heating areas 342 being oriented in opposite directions towards from each other. The second main heating areas 342 may have the length LMHA2 along the longitudinal direction of the second heat generation elements 340, the width WMHA2 along the lateral direction of the second heat generation elements 340, and there may be the distance DMHA2 between the second main heating areas 342a of the second heat generation element 340a and the opposite second main heating areas 342b of the opposite second heat generation element 340b. In some examples, the distance DMHA2 may be between 6.0 mm and 7.7 mm, inclusive. In other examples, the distance DMHA2 may be less than 6.0 mm or greater than 7.7 mm. The second auxiliary heating areas 344 may have the length LAHA2 along the longitudinal direction of the second heat generation elements 340 and the width WAHA2 along the lateral direction of the second heat generation elements 340. The second transition areas 348 may have the length LTA2 along the longitudinal direction of the second heat generation elements 340. There may be the distance DMHAS between the first heat generation elements 310 and corresponding of the second heat generation elements 340 adjacent to the first heat generation elements 310. When the first heat generation elements 310 are arranged between the second heat generation elements 340, there may be a distance D02 between the second main heating areas 342 and the sides of the heater structure 300 (e.g., the longitudinal sides of the heater structure 300.

[0064] According to the example shown in FIG. 5, the second recesses 346 of the second heat generation elements 340 and corresponding of the first recesses 316 of the first heat generation elements 310 adjacent to the second heat generation elements 340 are oriented in opposite directions away from each other based on the second main heating areas 342 of the4894-9433-2367.1Atty. Dkt. No.: 86344674 second heat generation elements 340 and corresponding of the first main heating areas 312 of the first heat generation elements 310 adjacent to the second heat generation elements 340 being oriented in opposite directions towards each other.

[0065] In the example shown in FIG. 6, the heater structure 300 includes the first heat generation element 310a, the opposite first heat generation element 310b, the second heat generation element 340a, and the opposite second heat generation element 340b. According to the example shown in FIG. 6, the first heat generation elements 310 are arranged between the second heat generation elements 340. The first heat generation elements 310 and the second heat generation elements 340 may define the gaps 302 positioned between the first heat generation elements 310 and the second heat generation elements 340.

[0066] As shown in FIG. 6, the heater structure 300 includes the wires 380 coupled to each of the first heat generation elements 310 and the second heat generation elements 340. According to the example shown in FIG. 6, the wires 380 include the first wire 382 electrically coupled to a first end of the second heat generation element 340a, the second wire 384 electrically coupled to a first end of the first heat generation element 310a, the third wire 386 electrically coupled to a second end of the second heat generation element 340a and a first end of the opposite second heat generation element 340b, the fourth wire 388 electrically coupled to a second end of the first heat generation element 310a and a first end of the opposite first heat generation element 310b, and the fifth wire 390 electrically coupled to a second end of the opposite second heat generation element 340b and a second end of the opposite first heat generation element 310b. According to the example shown in FIG. 6, the wires 380 further define the gaps 302 positioned between the wires 380.

[0067] The first heat generation elements 310 may include the first main heating areas 312, the first auxiliary heating areas 314, the first transition areas 318, the first edges 320, and the first deviated edges 322. The first main heating areas 312 and the first auxiliary heating areas 314 may cooperatively define the first recesses 316. According to the example shown in FIG. 6, the first recesses 316 are oriented in opposite directions towards each other based on the first main heating areas 312 being oriented in opposite directions away from each other. The first main heating areas 312 may have the length LMHAI along the longitudinal direction of the first heat generation elements 310 and the width WMHAI along the lateral direction of the first heat generation elements 310. The first auxiliary heating areas 314 may have the length LAHAI along the longitudinal direction of the first heat generation elements 310, the width4894-9433-2367.1Atty. Dkt. No.: 86344674WAHAI along the lateral direction of the first heat generation elements 310, and there may be the distance DAHAI between the first auxiliary heating areas 314a of the first heat generation element 310a and the opposite first auxiliary heating areas 314b of the opposite first heat generation element 310b. The first transition areas 318 may have the length LTAI along the longitudinal direction of the first heat generation elements 310.

[0068] The second heat generation elements 340 may include the second main heating areas 342, the second auxiliary heating areas 344, the second transition areas 348, the second edge 350, the second deviated edges 352, the extended portions 354, and the extension transition areas 356. According to the example shown in FIG. 6, the second main heating areas 342, the second auxiliary heating areas 344, and the extended portions 354 cooperatively define the second recesses 346 and the second recesses 346 are oriented in opposite directions away from each other based on the second main heating areas 342 being oriented in opposite directions towards from each other. The second main heating areas 342 may have the length LMHA2 along the longitudinal direction of the second heat generation elements 340, the width WMHA2 along the lateral direction of the second heat generation elements 340, and there may be the distance DMHA2 between the second main heating areas 342a of the second heat generation element 340a and the opposite second main heating areas 342b of the opposite second heat generation element 340b. The second auxiliary heating areas 344 may have the length LAHA2 along the longitudinal direction of the second heat generation elements 340 and the width WAHA2 along the lateral direction of the second heat generation elements 340. The second transition areas 348 may have the length LTA2 along the longitudinal direction of the second heat generation elements 340. The extended portions 354 may have the length LEP2 along the longitudinal direction of the second heat generation elements 340 and the width WEP2 along the lateral direction of the second heat generation elements 340. The extension transition areas 356 may have the length LETA2 along the longitudinal direction of the second heat generation elements 340. There may be the distance DMHAS between the first heat generation elements 310 and corresponding of the second heat generation elements 340 adjacent to the first heat generation elements 310. The extension transition areas 356, the second main heating areas 342, the second transition areas 348, and the second auxiliary heating areas 344 may have the combined length LRP3 along the longitudinal direction of the second heat generation elements 340. When the first heat generation elements 310 are arranged between the second heat generation elements 340, there may be the distance D024894-9433-2367.1Atty. Dkt. No.: 86344674 between the second main heating areas 342 and the sides of the heater structure 300 (e.g., the longitudinal sides of the heater structure 300.

[0069] According to the example shown in FIG. 6, the second recesses 346 of the second heat generation elements 340 and corresponding of the first recesses 316 of the first heat generation elements 310 adjacent to the second heat generation elements 340 are oriented in opposite directions away from each other based on the second main heating areas 342 of the second heat generation elements 340 and corresponding of the first main heating areas 312 of the first heat generation elements 310 adjacent to the second heat generation elements 340 being oriented in opposite directions towards each other.

[0070] As shown in FIG. 7A, a first table depicts setting values for the heat generation amount for the first heat generation elements 310 and the second heat generation elements 340 across different sections of the heater structure 300 in Watts. In some examples, the first section may correspond to a first portion of the heater structure 300 extending longitudinally across the heater structure 300 from an outer end of a first of the first auxiliary heating areas 314 to a first end of the first main heating areas 312, the second section may correspond to a second portion of the heater structure 300 extending longitudinally across the heater structure 300 from the first section across a first portion of the first main heating areas 312, the third section may correspond to a third portion of the heater structure 300 extending longitudinally across the heater structure 300 from the second section across a second portion of the first main heating areas 312, the fourth section may correspond to a fourth portion of the heater structure 300 extending longitudinally across the heater structure 300 from the third section across a third portion of the first main heating areas 312, the fifth section may correspond to a fifth portion of the heater structure 300 extending longitudinally across the heater structure 300 from the fourth section to a second end of the first main heating areas 312, and the sixth section may correspond to a sixth portion of the heater structure 300 extending longitudinally across the heater structure 300 from the fifth section to an outer end of a second of the first auxiliary heating areas 314.

[0071] In some examples, the setting value for the heat generation amount foreach of the first section and the second section of the heater structure 300 may substantially close to the setting value for the heat generation amount for each of the second section, the third section, the fourth section, and the fifth section of the heater structure 300 such that variations in temperatures across the belt 226 may be substantially low. For example, an example4894-9433-2367.1Atty. Dkt. No.: 86344674 comparative heater structure may include comparative first heat generation elements including one or more comparative first recess portions located on a middle portion of the comparative first heat generation elements and comparative second heat generation elements including one or more comparative second recess portions located on side portions of the comparative second heat generation elements, where the one or more comparative first recess portions and corresponding of the one or more comparative second recess portions are oriented towards each other. A first difference between the setting value of the heat generation amount for each of the first section and the sixth section of the heater structure 300 and the setting value of the heat generation amount for each of the second section, the third section, the fourth section, and the fifth section of the heater structure 300 may be lower than a second difference between the setting value of the heat generation amount for each of a first section and a sixth section of the comparative heater structure and the setting value of the heat generation amount for each of a second section, a third section, a fourth section, and a fifth section of the comparative heater structure. As a result of the first difference being lower than the second difference, the heater structure 300 may cause a lower variation in temperatures across the belt 226 than the comparative heater structure, which may increase an operational lifespan of the belt 226.

[0072] As shown in FIG. 7B, a first graph depicts variations in temperatures of the belt 226 across the nip width of the fixing apparatus 200 based on the heat generated by the heater structure 300 and provided to the belt 226 to provide to the printing medium P. The first graph 450 includes center temperatures 452 corresponding to first temperatures along a center of the belt 226 across the nip width of the fixing apparatus 200 and side temperatures 454 corresponding to second temperatures along a side of the belt 226 across the nip width of the fixing apparatus 200. As shown in the first graph, variations between the center temperatures 452 and the side temperatures 454 are substantially low across the nip width of the fixing apparatus 200. For example, an example comparative heater structure may include comparative first heat generation elements including one or more comparative first recess portions located on a middle portion of the comparative first heat generation elements and comparative second heat generation elements including one or more comparative second recess portions located on side portions of the comparative second heat generation elements, where the one or more comparative first recess portions and corresponding of the one or more comparative second recess portions are oriented towards each other. First variations between the center temperatures 452 and the side temperatures 454 of the belt 226 at points across the4894-9433-2367.1Atty. Dkt. No.: 86344674 nip width of the fixing apparatus 200 when the fixing apparatus 200 includes the heater structure 300 may be lower than second variations between center temperatures and side temperatures of the belt 226 at points across the nip width of the fixing apparatus 200 when the fixing apparatus 200 incudes the comparative heater structure. For example, a first maximum of the first variations between the center temperatures 452 and the side temperatures 454 of the belt 226 from the heat provided to the belt 226 from the heater structure 300 may be lower than a second maximum of the second variations between the center temperatures and the side temperatures of the belt 226 from the heat provided to the belt 226 from the comparative heater structure.

[0073] As shown in FIG. 8, a second graph 500 depicts fusing temperatures of printing materials on printing mediums for the heater structure 300 and an example comparative heater structure. The comparative heater structure may include comparative first heat generation elements including one or more comparative first recess portions located on a middle portion of the comparative first heat generation elements and comparative second heat generation elements including one or more comparative second recess portions located on side portions of the comparative second heat generation elements, where the one or more comparative first recess portions and corresponding of the one or more comparative second recess portions are oriented towards each other. When the comparative second heat generation elements are arranged between the comparative first heat generation elements, a first distance between the one or more comparative first recess portions and longitudinal sides of the comparative heater structure may be less than the distance Doi between the first main heating areas 312 and the longitudinal sides of the heater structure 300 when the second heat generation elements 340 are arranged between the first heat generation elements 310. When the comparative first heat generation elements are arranged between the comparative second heat generation elements, a second distance between the one or more comparative second recess portions and longitudinal sides of the comparative heater structure may be less than the distance D02 between the second main heating areas 342 and the longitudinal sides of the heater structure 300 when the first heat generation elements 310 are arranged between the second heat generation elements 340.

[0074] As shown in FIG. 8, since the first main heating areas 312 or the second main heating areas 342 are positioned closer to the longitudinal sides of the heater structure 300 than the one or more comparative first recess portions or the one or more comparative second recess4894-9433-2367.1Atty. Dkt. No.: 86344674 portions are to the longitudinal sides of the comparative heater structure, the heater structure 300 may be able to fuse printing material to the printing mediums with lower fusing temperatures than the comparative heater structure. For example, as shown in the second graph 500, in a high coverage printing scenario (e.g., a scenario where the printing material covers a high percentage of the printing medium, a scenario where the printing medium is a wide printing medium, etc.), the heater structure 300 may fuse the print material to the printing medium with a lower fusing temperature than the comparative heater structure. As another example, as shown in the second graph 500, in a low coverage printing scenario (e.g., a scenario where the printing material covers a lower percentage of the printing medium, a scenario where the printing medium is a narrow printing medium, etc.), the heater structure 300 may fuse the print material to the printing medium with a lower fusing temperature than the comparative heater structure.

[0075] As shown in FIG. 8, a third graph 550 depicts energy consumption of the heater structure 300 and the comparative heater structure in Watt-hours that correspond to the fusing temperatures depicted in the second graph 500. As a result of the heater structure 300 being able to fuse the printing material to the printing mediums with the lower fusing temperatures than the comparative heater structure, the heater structure 300 may consume less energy than the comparative heater structure. For example, as shown in the third graph 550, since the heater structure 300 may fuse the print material to the printing material with the lower fusing temperature than the comparative heater structure in the high coverage printing scenario, the heater structure 300 may consume less energy in the high coverage printing scenario than the comparative heater structure. As another example, as shown in the third graph 550, since the heater structure 300 may fuse the print material to the printing material with the lower fusing temperature than the comparative heater structure in the low coverage printing scenario, the heater structure 300 may consume less energy in the low coverage printing scenario than the comparative heater structure. As a result, an image forming apparatus utilizing the heater structure 300 may be more energy efficient than an image forming apparatus utilizing the comparative heater structure.

[0076] As shown in FIG. 9A, a fourth graph depicts a maximum temperature of the belt 226 at an edge of the printing material for different heating lengths of the first heat generation elements 310 and the second heat generation elements 340 of the heater structure 300 when the second heat generation elements 340 are arranged between the first heat generation4894-9433-2367.1Atty. Dkt. No.: 86344674 elements 310 and the second heat generation elements 340 include the extended portions 354. The fourth graph may depict a maximum temperature 602 of the belt 226 at an edge of ledger sized printing material after printing 200 pages of the ledger sized printing material at a 46 print per minute printing speed. For example, the fourth graph may depict the maximum temperature 602 of the belt 226 when the first heat generation elements 310 and the second heat generation elements 340 have a heating length of 305 mm, a heating length of 307 mm, a heating length of 309 mm, and a heating length of 311mm. As shown in FIG. 9A, the maximum temperature 602 of the belt 226 is below a temperature threshold 604 of the belt 226. The temperature threshold 604 may be a temperature of the belt 226 where an operational lifespan of the belt 226 begins to decrease at an increasing rate. For example, the temperature threshold 604 of the belt 226 may be determined by failure testing the belt 226 at different temperatures.

[0077] As shown in FIG. 9B, a second table compares fusing performances of the belt 226 that correspond to the maximum temperature 602 depicted in the fourth graph of FIG. 9 A for the heater structure 300 when the second heat generation elements 340 are arranged between the first heat generation elements 310 and the second heat generation elements 340 include the extended portions 354. As shown in the second table, when the heating length of the first heat generation elements 310 and the second heat generation elements 340 is 305 mm, the maximum temperature 602 of the belt 226 at the edge of the printing medium is 205 °C, which is below the temperature threshold 604. However, the heating length of the first heat generation elements 310 and the second heat generation elements 340 being 305 mm results in a fusing performance of “Not Good”. For example, the heating length of the first heat generation elements 310 and the second heat generation elements 340 being 305 mm may result in printing material not being fixed along the edges of the printing mediums. As shown in the second table, when the heating length of the first heat generation elements 310 and the second heat generation elements 340 is 311 mm, the maximum temperature 602 of the belt 226 at the edge of the printing medium is 223 °C, which is below the temperature threshold 604. Additionally, the heating length of the first heat generation elements 310 and the second heat generation elements 340 being 311 mm results in a fusing performance of “OK”. For example, the heating length of the first heat generation elements 310 and the second heat generation elements 340 being 311 mm may result in printing material being fixed along the edges of the printing mediums.4894-9433-2367.1Atty. Dkt. No.: 86344674

[0078] As shown in FIG. 10 an example fifth graph 700 depicts temperature distributions of the belt 226 and printing material (e.g., toner, etc.) on a printing medium over the nip width of the fixing apparatus 200. The fifth graph 700 depicts the temperature distributions of the belt 226 and the printing material on the printing medium over the nip width of the fixing apparatus 200 when the fixing apparatus 200 includes the heater structure 300 and when the fixing apparatus 200 includes an example comparative heater structure. The comparative heater structure may include comparative first heat generation elements including one or more comparative first recess portions located on a middle portion of the comparative first heat generation elements and comparative second heat generation elements including one or more comparative second recess portions located on side portions of the comparative second heat generation elements, where the one or more comparative first recess portions and corresponding of the one or more comparative second recess portions are oriented towards each other. As shown in the fifth graph 700, first belt temperatures 702 corresponding to the fixing apparatus 200 including the heater structure 300 are different from second belt temperatures 704 corresponding to the fixing apparatus 200 including the comparative heating structure. For example, peaks and valleys of the first belt temperature 702 may be positioned at different points along the nip width of the fixing apparatus 200 than peaks and valleys of the second belt temperatures 704. As shown in the fifth graph 700, the first belt temperatures 702 result in first toner temperatures 706 of the printing material on the printing mediums and the second belt temperatures 704 result in second toner temperatures 708 of the printing material on the printing mediums. At an end of the nip width of the fixing apparatus 200, the first toner temperatures 706 may be higher than the second toner temperatures 708. The printing material brought to the first toner temperatures 706 by the fixing apparatus 200 including the heater structure 300 may be better fixed to the printing medium than the printing material brought to the second toner temperatures 708 by the fixing apparatus 200 including the comparative heater structure.

[0079] As shown in FIG. 11, an example sixth graph 800 depicts variations in temperature of the belt 226 over a printing time. The sixth graph 800 depicts temperatures of a center of the belt 226 and a side of the belt 226 over a printing time when the fixing apparatus 200 includes the heater structure 300 and when the fixing apparatus 200 includes an example comparative heater structure. The comparative heater structure may include comparative first heat generation elements including one or more comparative first recess portions located on a middle portion of the comparative first heat generation elements and comparative second4894-9433-2367.1Atty. Dkt. No.: 86344674 heat generation elements including one or more comparative second recess portions located on side portions of the comparative second heat generation elements, where the one or more comparative first recess portions and corresponding of the one or more comparative second recess portions are oriented towards each other. The sixth graph 800 depicts a first center temperature 802 of the belt 226 and a first side temperature 804 of the belt 226 when the fixing apparatus 200 includes the heater structure 300 and a second center temperature 806 of the belt 226 and a second side temperature 808 of the belt 226 when the fixing apparatus 200 includes the comparative heater assembly. As shown in FIG. 11, a first difference between the first center temperature 802 and the first side temperature 804 is smaller than a second difference between the second center temperature 806 and the second side temperature 808 over a majority of the printing time. As a result, variations in the temperature of the belt 226 are smaller over the majority of the printing time when the fixing apparatus 200 includes the heater structure 300 than when the fixing apparatus 200 includes the comparative heater structure, which may cause the belt 226 to have a longer operational lifespan when the fixing apparatus 200 includes the heater structure 300 than when the fixing apparatus 200 includes the comparative heater structure. Additionally, the first side temperature 804 is lower than the second side temperature 808 across the printing time, which may result in the temperature at the sides of the belt 226 remaining below a temperature threshold associated with the belt 226.

[0080] In an aspect of the present disclosure, a heater structure is disclosed. The heater structure includes a pair of first heat generation elements including one or more first recess portions and a pair of second heat generation elements including one or more second recess portions. Each of the pair of first heat generation elements has a first main heating area in a middle portion along a longitudinal direction of the pair of first heat generation elements. Each of the pair of second heat generation elements has second main heating areas on a first side and a second side respectively of the pair of second heat generation elements. The one or more first recess portions are located on the middle portion of the pair of first heat generation elements being between a first side and a second side of the pair of first heat generation elements. The one or more second recess portions are located on the first side and the second side of the pair of second heat generation elements. The one or more of the first recess portions and corresponding of the one or more second recess portions are oriented in opposite directions.4894-9433-2367.1Atty. Dkt. No.: 86344674

[0081] In some examples, a width of the second heat generation elements at each side is greater than a width of the one or more second recess portions. In some examples, a width of the second heat generation elements is increasing at an end of the one or more second recess portions. In some examples, the pair of second heat generation elements are arranged between the pair of first heat generation elements. In some examples, the pair of first heat generation elements are arranged between the pair of the second heat generation elements. In some examples, the one or more first recess portions and corresponding of the one or more second recess portions are oriented away from each other.

[0082] In another aspect of the present disclosure, a heater structure includes a pair of first heat generation elements including one or more first recess portions and a pair of second heat generation elements includes one or more second recess portions. Each of pair of first heat generation elements has a first main heating area in a middle portion along a longitudinal direction of the heater structure. Each of the pair of second heat generation elements has second main heating areas at both sides of the pair of second heat generation elements. The one or more first recess portions are located towards an outside of the heater structure. The one or more second recess portions are located to face each other.

[0083] In some examples, each of the pair of first heat generation elements has first auxiliary heating areas at both sides of the pair of first heat generation elements and a ratio between a first width of the first main heating areas and a second width of the auxiliary heating areas is greater than 1.3. In some examples, a distance between each of the pair of first heat generation elements and a corresponding one of the pair of second heat generation elements is between 0.1 mm and 1.0 mm, inclusive. In some examples, a width of the second heat generation elements at each side is greater than a width of the one or more second recess portions. In some examples, a width of the second heat generation elements is increasing at an end of the one or more second recess portions. In some examples, each of the pair of first heat generation elements has first auxiliary heating areas at both sides of the pair of first heat generation elements and a ratio between a first width of the first main heating areas and a second width of the auxiliary heating areas is greater than 1.3. In some examples, the heater structure is to be received by an image forming apparatus and a heating length of the pair of second heat generation elements is greater than a maximum width of a printing medium handled by the image forming apparatus.4894-9433-2367.1Atty. Dkt. No.: 86344674

[0084] In yet another aspect of the present disclosure, a heater includes a pair of first heat generation elements including a first straight edge on one longitudinal side and a pair of second heat generation elements including a second straight edge on one longitudinal side. Each of the pair of first heat generation elements has a first main heating area in a middle portion along a longitudinal direction of the pair of first heat generation elements. Each of the pair of second heat generation elements has second main heating areas on a first side and a second side respectively of the pair of second heat generation elements. The first straight edge of the first heat generation elements and the second straight edge of adjacent of the second heat generation elements are positioned to face each other. In some examples, a width of the pair of second heat generation elements is greater than a width of the pair of first heat generation elements.

[0085] It should be understood that examples described herein should be considered in a descriptive sense and not for purposes of limitation. Descriptions of features or aspects within each example should be considered as available for other similar features or aspects in other examples. While examples have been described with reference to the figures, it should be understood that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.

[0086] The disclosure has been described above with reference to the various examples. However, it is to be understood by those of ordinary skill in the art that various modifications may be made in form and detail without departing from the scope of the disclosure as defined by the appended claims and their equivalents.

[0087] Conditional language used herein, such as, among others, "can," "could," "might," "may," “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain examples include, while other examples do not include, certain features, elements. Thus, such conditional language is not generally intended to imply that features, elements are in any way required for examples or those examples include logic for deciding, with or without other input or prompting, whether these features, elements are included or are to be performed in any particular example. The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its4894-9433-2367.1Atty. Dkt. No.: 86344674 inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list.

[0088] While the above detailed description has shown, described, and pointed out novel features as applied to various examples, it can be understood that various omissions, substitutions, and changes in the form and details of the devices illustrated can be made without departing from the spirit of the disclosure. As can be recognized, certain examples described herein can be embodied within a form that does not provide all of the features and benefits set forth herein, as some features can be used or practiced separately from others.

[0089] The herein described subject matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely examples, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as "associated with" each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being "operably connected," or "operably coupled," to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being "operably couplable," to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and / or physically interacting components and / or wirelessly interactable and / or wirelessly interacting components and / or logically interacting and / or logically interactable components.

[0090] With respect to the use of substantially any plural and / or singular terms herein, those having skill in the art can translate from the plural to the singular and / or from the singular to the plural as is appropriate to the context and / or application. The various singular / plural permutations may be expressly set forth herein for sake of clarity.

[0091] It should be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should4894-9433-2367.1Atty. Dkt. No.: 86344674 be interpreted as "includes but is not limited to," etc.). It should be understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent should be explicitly recited in the claim, and in the absence of such recitation no such intent is present. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art should recognize that such recitation should typically be interpreted to mean at least the recited number. It should be understood by those within the art that virtually any disjunctive word and / or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" should be understood to include the possibilities of "A" or "B" or "A and B." Furthermore, unless otherwise noted, the use of the words “approximate,” “about,” “around,” “substantially,” etc., mean plus or minus ten percent.

[0092] The foregoing description of illustrative examples has been presented for purposes of illustration and of description. It is not intended to be exhaustive or limiting with respect to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the disclosed examples.4894-9433-2367.1

Claims

Atty. Dkt. No.: 86344674WHAT IS CLAIMED IS:

1. A heater structure comprising: a pair of first heat generation elements comprising one or more first recess portions; and a pair of second heat generation elements comprising one or more second recess portions; wherein each of the pair of first heat generation elements has a first main heating area in a middle portion along a longitudinal direction of the pair of first heat generation elements; wherein each of the pair of second heat generation elements has second main heating areas on a first side and a second side respectively of the pair of second heat generation elements; wherein the one or more first recess portions are located on the middle portion of the pair of first heat generation elements being between a first side and a second side of the pair of first heat generation elements; wherein the one or more second recess portions are located on the first side and the second side of the pair of second heat generation elements; and wherein the one or more first recess portions and corresponding of the one or more second recess portions are oriented in opposite directions.

2. The heater structure of claim 1, wherein a width of the second heat generation elements at each side is greater than a width of the one or more second recess portions.

3. The heater structure of claim 2, wherein a width of the second heat generation elements is increasing at an end of the one or more second recess portions.

4. The heater structure of claim 1, wherein the pair of second heat generation elements are arranged between the pair of first heat generation elements.

5. The heater structure of claim 1, wherein the pair of first heat generation elements are arranged between the pair of the second heat generation elements.

6. The heater structure of claim 1, wherein the one or more first recess portions and corresponding of the one or more second recess portions are oriented away from each other.

7. A heater structure comprising: -9433-2367.1Atty. Dkt. No.: 86344674 a pair of first heat generation elements comprising one or more first recess portions; and a pair of second heat generation elements comprising one or more second recess portions; wherein each of the pair of first heat generation elements has a first main heating area in a middle portion along a longitudinal direction of the heater structure; wherein each of the pair of second heat generation elements has second main heating areas at both sides of the pair of second heat generation elements; wherein the one or more first recess portions are located towards an outside of the heater structure; and wherein the one or more second recess portions are located to face each other.

8. The heater structure of claim 7, wherein: each of the pair of first heat generation elements has first auxiliary heating areas at both sides of the pair of first heat generation elements; and a ratio between a first width of the first main heating areas and a second width of the auxiliary heating areas is greater than 1.3.

9. The heater structure of claim 7, wherein a distance between each of the pair of first heat generation elements and a corresponding one of the pair of second heat generation elements is between 0.1 mm and 1.0 mm, inclusive.

10. The heater structure of claim 7, wherein a width of the second heat generation elements at each side is greater than a width of the one or more second recess portions.

11. The heater structure of claim 7, wherein a width of the second heat generation elements is increasing at an end of the one or more second recess portions.

12. The heater structure of claim 10, wherein: each of the pair of first heat generation elements has first auxiliary heating areas at both sides of the pair of first heat generation elements; and a ratio between a first width of the first main heating areas and a second width of the auxiliary heating areas is greater than 1.3.

13. The heater structure of claim 10, wherein: the heater structure is to be received by an image forming apparatus; and -9433-2367.1Atty. Dkt. No.: 86344674 a heating length of the pair of second heat generation elements is greater than a maximum width of a printing medium handled by the image forming apparatus.

14. A heater compri sing : a pair of first heat generation elements comprising a first straight edge on one longitudinal side; and a pair of second heat generation elements comprising a second straight edge on one longitudinal side; wherein each of the pair of first heat generation elements has a first main heating area in a middle portion along a longitudinal direction of the pair of first heat generation elements; wherein each of the pair of second heat generation elements has second main heating areas on a first side and a second side respectively of the pair of second heat generation elements; and wherein the first straight edge of the first heat generation elements and the second straight edge of an adjacent of the second heat generation elements are positioned to face each other.

15. The heater of claim 14, wherein a width of the pair of second heat generation elements at each side is greater than a width of the pair of first heat generation elements second main heating areas. -9433-2367.1

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