Fixing device and image forming apparatus

Abstract

To solve the problem that, in a fixing device having a cleaning member capable of cleaning a rotating body, when printing on a medium having a specific width is continued, a developer adheres to a specific region of the cleaning member and cleaning is not sufficiently performed in some cases.SOLUTION: The cleaning device includes a fixing belt 110, a first cleaning roller 140 having a shaft 140a and an elastic layer 140b and cleaning the fixing belt 110, a second cleaning roller 150 having a shaft 150a and an elastic layer 150b and cleaning the fixing belt 110, and an urging mechanism for urging these cleaning rollers to the fixing belt 110. In the longitudinal direction of the fixing belt 110, the second contact area where the elastic layer 150b is present and the first contact area where the elastic layer 140b is present have an overlapping area Sw, the overlapping area Sw includes a width-directional end of a recording sheet to be subjected to fixing processing, and the biasing mechanism has a pressure member 145 for biasing the shaft 140a in an area excluding the overlapping area Sw.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus, and more particularly to a fixing device having a cleaning function. [Background technology]

[0002] 2. Description of the Related Art Conventionally, fixing devices have been known that have a cleaning member capable of cleaning a rotating body (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 2-51369 (page 5, Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a problem that, for example, when printing on a medium having a specific width is continued, developer may adhere to a specific area of ​​the cleaning member in the axial direction of the rotating body, and cleaning may not be performed sufficiently. An object of the present invention is to provide a fixing device that can reduce the occurrence of cleaning failures. [Means for solving the problem]

[0005] A fixing device according to the present invention comprises a first rotating body extending in a first direction, a plurality of cleaning members arranged in the circumferential direction of the first rotating body and each having an elastic body that contacts and cleans the first rotating body, and a biasing mechanism that biases the plurality of cleaning members toward the first rotating body, wherein the plurality of cleaning members comprise a first cleaning member having a first support and a first elastic body supported by the first support, and a second cleaning member having a second support and a second elastic body supported by the second support, wherein in the first direction, a second contact area where the second elastic body contacts the first rotating body has an overlapping area where the first elastic body contacts the first rotating body, and the overlapping area includes a position corresponding to the widthwise end of a medium of a predetermined standard size to be fixed, and the biasing mechanism comprises a biasing member that applies a biasing force to the first support in an area different from the overlapping area. [Effects of the Invention]

[0006] According to the present invention, it is possible to perform cleaning evenly in the predetermined area of ​​the first rotating body in the first direction. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram illustrating a main configuration of an image forming apparatus according to a first embodiment of the present invention, which is provided with a fixing device; [Figure 2] 1 is a perspective view of the appearance of a fixing belt unit and a pressure roller that constitute the main part of a fixing device according to the present invention; [Figure 3] 3 is an enlarged perspective view of the exterior of the fixing belt unit and the vicinity of the right end of the pressure roller, as viewed from an angle different from that of FIG. 2. FIG. [Figure 4] 3A is a cross-sectional view of the main part of the fixing device shown in FIG. 2, taken at the center of its width, as viewed from the left side, and FIG. 3B is an enlarged view of the nip portion in FIG. 3A. [Figure 5]1 is a schematic plan view illustrating the positional relationship in the longitudinal direction (Y direction) of a first cleaning roller, a second cleaning roller, and the maximum paper width Aw that can be printed in specifications. FIG. [Figure 6] FIG. 10 is an explanatory diagram illustrating a case where continuous printing is performed in the specific area Pw1 using recording paper and a print pattern having this width. [Figure 7] 10 is an explanatory diagram illustrating a case where continuous printing is performed in a specific area Pw2 that is narrower than the specific area Pw1 using recording paper and a print pattern of this width. [Figure 8] FIG. 10 is a schematic plan view illustrating the positional relationship in the longitudinal direction (Y direction) of a first cleaning roller, a third cleaning roller, a fourth cleaning roller, and a fifth cleaning roller in a second embodiment according to the present invention. [Figure 9] FIG. 10(a) is a schematic plan view illustrating the positional relationship between the sixth cleaning roller and the seventh cleaning roller in the third embodiment of the present invention, and FIG. 10(b) is a diagram illustrating the pressure distribution of each elastic layer at the maximum paper width Aw in the specifications. [Figure 10] 10 is a schematic plan view illustrating the positional relationship in the width direction (arrow Y direction) of a first cleaning roller, a second cleaning roller, a main heater, two sub-heaters A, and two sub-heaters B in a fourth embodiment according to the present invention. FIG. 10 is a schematic plan view illustrating the positional relationship in the width direction (arrow Y direction) of the first cleaning roller, the second cleaning roller, the main heater, and two sub-heaters. [Figure 11] FIG. 10 is a schematic plan view illustrating the positional relationship in the width direction (direction of arrow Y) of a first cleaning roller, a second cleaning roller, a main heater, and two sub-heaters A in a fifth embodiment according to the present invention. [Figure 12] FIG. 10 is a schematic diagram of a cleaning roller shown as a reference example. DETAILED DESCRIPTION OF THE INVENTION

[0008] Embodiment 1 FIG. 1 is a schematic diagram illustrating the main configuration of an image forming apparatus 1000 according to a first embodiment, which is equipped with a fixing device 100 according to the present invention.

[0009] The image forming apparatus 1000 shown in the figure has a configuration as, for example, a color electrophotographic printer, and inside the apparatus is installed a paper feed cassette 1004 that stores recording paper 1001 as a recording medium, a paper feed roller 1005 that removes the recording paper 1001 from the paper feed cassette 1004, and a pair of registration rollers 1006 that feed the recording paper 1001 to the image forming section at a predetermined timing.

[0010] Furthermore, within image forming apparatus 1000, as image forming sections, developing device 1010K that forms a black (K) toner image, developing device 1010Y that forms a yellow (Y) toner image, developing device 1010M that forms a magenta (M) toner image, and developing device 1010C that forms a cyan (C) toner image (these developing devices may be simply referred to as 1010 when there is no need to particularly distinguish between them) are arranged in this order from the upstream side along the transport path of recording paper 1001. These developing devices 1010 have the same configuration except that they use toner of a predetermined color.

[0011] For example, as shown in developing device 1010K that uses black (K) toner, each developing device 1010 includes a photosensitive drum 1011, a charging device 1012 that supplies electric charge to the surface of the photosensitive drum 1011 and charges it, arranged around the photosensitive drum 1011 in order from the upstream side in the rotation direction (arrow direction), an exposure device 1013 that selectively irradiates the surface of the charged photosensitive drum 1011 with light based on image data to form an electrostatic latent image, a developer supply device 1014 that develops the electrostatic latent image formed on the photosensitive drum 1011 with the toner to form a toner image, and a cleaning device 1015 that is arranged in contact with the photosensitive drum 1011 to remove toner remaining on the surface of the photosensitive drum 1011.

[0012] The image forming apparatus 1000 also includes a belt-type transfer device 1020, which includes an endless transfer belt 1021 that transports recording paper 1001 and sequentially transfers toner images formed by each developing device onto the transported recording paper 1001, a drive roller 1022 that is rotated by a drive unit (not shown) to drive the endless transfer belt 1021 in the direction of arrow A, and a tension roller 1023 that pairs with the drive roller 1022 and tensions the endless transfer belt 1021.

[0013] A fixing device 100 is provided on the discharge side of the recording paper 1001 from the endless transfer belt 1021. The fixing device 100 has a fixing belt unit 101 and a pressure roller 102, and fixes the toner transferred onto the recording paper 1001 by applying heat and pressure. Conveyor rollers 1030 and 1031 are provided on the discharge side of the fixing device 100, and the printed recording paper 1001 discharged from the fixing device 100 is discharged onto a paper discharge stacker 1032. The fixing device 100 will be described in detail later.

[0014] In FIG. 1, the X, Y, and Z directions are defined as the conveyance direction (direction of arrow A) of recording paper 1001 as it passes through developing devices 1010K, 1010Y, 1010M, and 1010C, the Y direction is the direction of the rotation axis of each photosensitive drum 1011, and the Z direction is the direction perpendicular to both of these directions. Furthermore, when the X, Y, and Z directions are shown in other figures described later, these directions refer to the same directions. That is, the X, Y, and Z directions in each figure indicate the arrangement direction when the depicted parts of each figure constitute the image forming apparatus 1000 shown in FIG. 1. Here, the Z direction is assumed to be approximately vertical.

[0015] In the above configuration, the printing operation of the image forming apparatus 1000 will be outlined with reference to Fig. 1. Note that the dotted arrow in Fig. 1 indicates the conveyance direction of the recording paper 1001 being conveyed.

[0016] When the image forming apparatus 1000 is turned on and an operator performs a well-known operation to start image formation, the recording paper 1001 stored in the paper feed cassette 1004 is removed from the paper feed cassette 1004 by the paper feed roller 1005, and after correcting any skew by a pair of registration rollers 1006, the recording paper is transported to an image forming section consisting of four developing devices 1010 and a transfer device 1020 at a predetermined timing.

[0017] At this time, as the photosensitive drum 1011 rotates in the direction of the arrow, the surface of the photosensitive drum 1011 of each developing device 1010 is charged by the charging device 1012 to which a voltage is applied by a power supply device (not shown). Next, when the charged surface of the photosensitive drum 1011 reaches the vicinity of the exposure device 1013, it is exposed by the exposure device 1013, and an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 1011. This electrostatic latent image is developed by the developer supply device 1014, and a toner image corresponding to each color is formed on the surface of the photosensitive drum 1011.

[0018] The recording paper 1001 transported to the image forming section is attracted to the endless transfer belt 1021 and transported in the direction of arrow A, and in the process of being sequentially nipped between the photosensitive drums 1011 of each developing device 1010 rotating in the direction of the arrow and the endless transfer belt 1021, toner images of each color of black (K), yellow (Y), magenta (M), and cyan (C) formed at a predetermined timing are sequentially transferred and superimposed, forming a color image with toner of each color on the recording paper 1001. After transfer, the photosensitive drum 1011 is cleaned by scraping off any remaining toner on the photosensitive drum 1011 with a cleaning device 1015, and then is prepared for the next charging.

[0019] Next, the recording paper 1001, on whose surface a color image has been formed using toner of each color, is transported to the fixing device 100. The toner image on the recording paper 1001 is melted by pressure and heat applied by the fixing device 100 and fixed to the recording paper 1001. Thereafter, the recording paper 1001 is discharged to a paper discharge stacking section 1032 by conveying rollers 1030 and 1031, and the printing operation is completed.

[0020] Fig. 2 is an external perspective view of the fixing belt unit 101 and pressure roller 102 that constitute the main parts of the fixing device 100 according to the present invention. Fig. 3 is an enlarged external perspective view of the vicinity of the right end of the fixing belt unit 101 and pressure roller 102, viewed from a different angle than in Fig. 2. Fig. 4(a) is a cross-sectional view of the main parts of the fixing device 100 shown in Fig. 2, taken at the center of its width, viewed from the left side, and Fig. 4(b) is an enlarged partial view of the vicinity of the nip portion in Fig. 4(a). Note that when viewed from the direction of arrow A (X direction) shown in Fig. 2, the top (positive direction of the Z axis), bottom, left, right, front, and rear may be specified.

[0021] As shown in these figures, inside the fixing device 100, a pressure roller 102 and a fixing belt unit 101 equipped with an endless fixing belt 110 positioned above the pressure roller 102 are arranged so that they both extend in the Y direction. The fixing belt 110 has a metal or resin layer serving as a base material on its inner surface, an elastic layer of silicone rubber on the outer layer of the base material, and a PFA tube on the surface. The pressure roller 102 is configured by laminating, from the center, a hollow metal core, an elastic layer, and a PFA tube layer on the surface.

[0022] 4, a heater unit 107 is disposed inside a fixing belt 110 serving as a first rotating body extending in the Y direction in the fixing belt unit 101, the heater unit 107 extending in the same direction and heating the fixing belt 110 from the inside. In addition, sliding grease is applied to the inner surface of the fixing belt 110. The Y direction as the first direction in which the fixing belt 110 extends may also be referred to as the longitudinal direction or the width direction of the recording paper 1001.

[0023] The pressure roller 102 has both ends of its rotation shaft 102a rotatably supported by a frame (not shown) of the fixing device 100, and receives an external rotational driving force to be rotated in the direction of the arrow (counterclockwise direction) in Fig. 4. The frame holds components such as the pressure roller 102 and the fixing belt unit 101 in place by left and right side plates (not shown).

[0024] The metal stay 111 constituting the heater unit 107 arranged inside the fixing belt 110 has a U-shaped cross section as shown in FIG. 4, extends beyond both ends of the fixing belt 110 in the Y direction, and is fixedly held by a metal right support lever 103R at a position beyond the right end of the fixing belt 110, and is fixedly held by a metal left support lever 103L (FIG. 2) at a position beyond the left end of the fixing belt 110.

[0025] The right support lever 103R holds a right guide member 106R made of heat-resistant sliding resin and having a right inner guide portion 104R that guides the upper part of the right end portion of the fixing belt 110 from the inside and a right regulating portion 105R that regulates the rightward movement of the fixing belt 110.Similarly, the left support lever 103L holds a left guide member (not shown) that has a left inner guide portion (not shown) that guides the upper part of the right end portion of the fixing belt 110 from the inside and a left regulating portion (not shown) that regulates the leftward movement of the fixing belt 110.

[0026] The right support lever 103R, right guide member 106R, heater unit 107, and opposing member 162 (described later) are configured in the same manner at the right end of the fixing belt unit 101, including a right side plate (not shown) of the frame. That is, these are formed approximately symmetrically with respect to an imaginary center plane that intersects perpendicularly at the center of the fixing belt unit 101 in the longitudinal direction (Y direction).

[0027] Therefore, to distinguish between left and right, the reference numerals of components arranged symmetrically at the left and right ends are suffixed with (L) and (R), for example, left support lever 103L and right support lever 103R, but when no particular distinction is necessary, these suffixes may be omitted and the components may be referred to as support lever 103. Furthermore, for the components arranged symmetrically at the left and right ends of the fixing belt unit 101, the configuration of the right end will mainly be described, and the left end will also be mentioned as necessary.

[0028] As shown in Fig. 4(b), the stay 111 holds a heater holder 112 that holds a thin plate-shaped heater 113 extending in the width direction, and both left and right ends of the heater holder 112 are fixedly held by the left and right support levers 103. As shown in Fig. 4(b), for example, the heater 113 is disposed on the bottom of the heater holder 112 via a thermistor that detects excessive temperature rise of the heater and a thermistor protection plate that protects the thermistor (not shown), and the underside of the heater holder 112 is further covered by a heat diffusion plate 114 attached to the heater holder 112. Therefore, the right support lever 103R, the right guide member 106R, and the right end of the heater unit 107 are integrally formed.

[0029] The fixing belt unit 101 has a right rotation shaft hole 115R formed at the lower end of the right support lever 103R, into which a right rotation fulcrum 131R of a frame (not shown) is fitted. As a result, the fixing belt unit 101 is held by the frame (not shown) of the fixing device 100 so as to be rotatable around the rotation fulcrum 131.

[0030] The fixing belt unit 101 configured as described above is biased in the direction of arrow C by a compression spring (not shown) that is suspended between a frame (not shown) and the right spring receiving portion 116R. The fixing belt unit 101 is further equipped with a first cleaning roller 140 and a second cleaning roller 150 according to the present invention, which will be described in detail later.

[0031] 4(b), this biasing causes the lower flat portion of the heat diffusion plate 114, which transfers heat to the fixing belt 110, to come into pressure contact with the elastic peripheral surface of the pressure roller 102 via the fixing belt 110, forming a nip portion 120. In this state, the fixing belt 110 rotates together with the pressure roller 102 as it rotates in the direction of the arrow.

[0032] At this time, the left and right ends and inner surface of the fixing belt 110 are guided by the left and right guide members 106, and the fixing belt 110 rotates clockwise following the rotation of the pressure roller 102. Note that the movement of the fixing belt 110 rotating on its own axis while moving at this time may be referred to as rotational movement.

[0033] As described above, the recording paper 1001 on which transfer has been completed passes through the nip portion 120 in the direction of the arrow B shown by the dotted line (FIG. 4(a)), and the transferred toner image is fixed by the heat and pressure treatment that the recording paper receives while passing through this nip portion 120, and the recording paper is then discharged from the fixing device 100. On the other hand, when the fixing belt 110 is to be separated from the pressure roller 102, the right contact flat surface 117R is pressed by a cam or the like (not shown), causing the fixing belt unit 101 to rotate clockwise and separate them.

[0034] In addition to the above-mentioned members, the fixing belt unit 101 further includes a first cleaning roller 140, a second cleaning roller 150, etc. These components will be described in detail below. The first cleaning roller 140 and the second cleaning roller 150 correspond to cleaning members.

[0035] The first cleaning roller 140, which serves as a first cleaning member, has a metallic shaft 140a, which serves as a first support extending in the longitudinal direction (the direction of the arrow Y), and is covered with an elastic layer 140b, which serves as a first elastic body and is formed into a roller shape using silicone rubber or heat-resistant felt. This elastic layer 140b does not cover the entire axial direction, and there is a portion of the shaft 140a that is exposed within the maximum paper width Aw (see FIG. 5) that can be printed in the specifications (hereinafter referred to as the maximum paper width in the specifications) (see FIG. 2).

[0036] 3, both ends of the metal shaft 140a are rotatably held by a rotary shaft holder 141R, for example, on the right side, as shown in Fig. 3, and this rotary shaft holder 141R is slidably held by a right support lever 103R so that the first cleaning roller 140 can approach and separate from the fixing belt 110. Furthermore, the rotary shaft holder 141R is biased by a compression spring 142R suspended between the right support lever 103R and the rotary shaft holder 141R.

[0037] Similarly, second cleaning roller 150, which serves as a second cleaning member, has a metallic shaft 150a (FIG. 4(a)) that serves as a second support extending in the longitudinal direction (arrow Y direction) and is covered with an elastic layer 150b that serves as a second elastic body and is made of silicone rubber or heat-resistant felt and formed into a roller shape. This elastic layer 150b does not cover the entire axial direction, and there is a portion of shaft 150a that is exposed within the specified maximum paper width Aw (see FIG. 5) (see FIG. 2).

[0038] 3, both ends of the metal shaft 150a are rotatably held by a rotary shaft holder 151R, for example, on the right side, as shown in Fig. 3, and this rotary shaft holder 151R is slidably held by a right support lever 103R so that the second cleaning roller 150 can approach and separate from the fixing belt 110. Furthermore, the rotary shaft holder 151R is biased by a compression spring 152R suspended between it and the right support lever 103R.

[0039] 2, the first cleaning roller 140 is provided with pressure members 145 at positions (four positions in this example) corresponding to the shaft 140a on which the elastic layer 140b is not formed and facing both ends of each elastic layer 140b. As shown in FIG. 4(a), each pressure member 145 is made up of an axial pressure part 145a that rotatably holds the penetrating shaft 140a, and a pair of arm parts 145b that are formed integrally with the axial pressure part 145a and are held by an upper frame 161 (described later) so as to be vertically movable.

[0040] Similarly, the second cleaning roller 150 has pressure members 155 disposed at positions (four positions in this example) corresponding to the shaft 150a on which no elastic layer 150b is formed and facing both ends of each elastic layer 150b, as shown in Fig. 2. As shown in Fig. 4(a), each pressure member 155 is made up of an axial pressure part 155a that rotatably holds the penetrating shaft 150a, and a pair of arm parts 155b that are formed integrally with the axial pressure part 155a and are held by an upper frame 161 (described later) so as to be vertically movable.

[0041] An upper frame 161 that holds the pressure members 145 and 155 extends in the longitudinal direction (the direction of arrow Y) and is bridged between the left and right support levers 103R and 103L, with both ends thereof integrally held by the support levers 103R and 103L. Note that in Figures 2 and 3, this upper frame 161 is omitted in order to clearly show the configuration of each part, but a cross section thereof is shown in Figure 4(a).

[0042] As shown in the cross-sectional view of Fig. 4(a), this upper frame 161 includes first holding portions 161a that hold the pressure members 145, second holding portions 161b that hold the pressure members 155, and connecting portions that connect these. The first holding portions 161a hold the four corresponding pressure members 145 as shown in Fig. 2, and since all of these are held by the same configuration and holding method, the holding method will be explained here using the pressure members 145 shown in Fig. 4(a) as an example.

[0043] The first holding portion 161a has guide holes (not shown) that pass through at positions where the pair of arm portions 145b of the pressure member 145 face each other, and slidably holds the pressure member 145 so that the elastic layer 140b of the first cleaning roller 140, which is rotatably held by the pressure member 145, can come into contact with and separate from the fixing belt 110. Furthermore, a compression spring 146 is hung between the first holding portion 161a and the axial pressure portion 145a of the pressure member 145. Therefore, the elastic layer 140b of the first cleaning roller 140 is pressed against the surface of the fixing belt 110 with a predetermined pressure due to the biasing force of the compression springs 142 and 146.

[0044] Similarly, the second holding portion 161b holds four corresponding pressure members 155 as shown in FIG. 2, but since all of these are held by the same configuration and holding method, the holding method will be explained here using the pressure member 155 shown in FIG. 4(a) as an example.

[0045] The second holding portion 161b has guide holes (not shown) that pass through at positions where the pair of arm portions 155b of the pressure member 155 face each other, and slidably holds the pressure member 155 so that the elastic layer 150b of the second cleaning roller 150, which is rotatably held by the pressure member 155, can come into contact with and separate from the fixing belt 110. Furthermore, a compression spring 156 is hung between the second holding portion 161b and the axial pressure portion 155a of the pressure member 155. Therefore, the elastic layer 150b of the second cleaning roller 150 is pressed against the surface of the fixing belt 110 with a predetermined pressure due to the biasing force of the compression springs 152 and 156.

[0046] An opposing member 162 (FIG. 4(a)) is provided inside the fixing belt 110 to support the fixing belt 110 from the inside against the pressure exerted on the fixing belt 110 by the first cleaning roller 140 and the second cleaning roller 150.

[0047] This opposing member 162 is fixedly disposed on the stay 111, extends in the same direction (Y direction) over a range exceeding at least the specified maximum paper width Aw (see FIG. 5), and supports the rotational movement of the fixing belt 110 from the inside, including the positions facing the first cleaning roller 140 and the second cleaning roller 150. Therefore, referring to FIG. 4(a), when the fixing belt 110 rotates in the clockwise direction, the first cleaning roller 140 and the second cleaning roller 150 each rotate in the counterclockwise direction in response to this rotational movement.

[0048] FIG. 5 is a schematic plan view illustrating the positional relationship in the longitudinal direction (Y direction) between the first cleaning roller 140, the second cleaning roller 150, and the maximum paper width Aw in the specifications, as shown in FIG. 2, for example.

[0049] In the figure, in the direction of arrow D in which fixing belt 110 rotates, the row in which first cleaning roller 140 is arranged may be referred to as the first row, and the row in which second cleaning roller 150 is arranged may be referred to as the second row.

[0050] The first cleaning roller 140 has two elastic layers 140b arranged on a shaft 140a at a predetermined interval in the longitudinal direction (Y direction) and centered within the maximum paper width Aw specified in the image forming apparatus 1000. Both ends of the shaft 140a are held by the left and right support levers 103 via rotation shaft biasing members 149R and 149L. Pressure members 145, which serve as biasing members and are held by the upper frame 161, are provided at positions facing both ends of each elastic layer 140b, rotatably holding the corresponding portions of the shaft 140a. Therefore, the rotation shaft biasing members 149 here correspond to the rotation shaft holder 141 and compression spring 142 in FIG. 3. It is assumed here that the pressures of the rotation shaft biasing members 149R and 149L and the pressure member 145 are set to be approximately the same.

[0051] In the region of the second cleaning roller 150 that exceeds the maximum paper width Aw specified in the longitudinal direction (Y direction), the shaft 150a is provided with an elastic layer 150c as a third elastic body located in the center to fill in the region where the elastic layer 140b of the first cleaning roller 140 is not present, and two elastic layers 150b located on either side of the elastic layer 150c. Furthermore, each elastic layer 150b, 150c has a width that overlaps with the end of the elastic layer 140b of the first cleaning roller 140 in an overlap region Sw. Therefore, the pressure member 145 is located in the region where the elastic layer 150b is present in the longitudinal direction, excluding the overlap region Sw.

[0052] In the longitudinal direction (Y direction), the region where the elastic layer 140b exists corresponds to the first contact region, and the region where the elastic layer 150b exists corresponds to the second contact region.

[0053] Both ends of shaft 150a are held by left and right support levers 103 via rotary shaft biasing portions 159R and 159L, and pressure members 155 held by upper frame 161 are provided at positions facing both ends of each elastic layer 150b to rotatably hold the corresponding portions of shaft 150a. Therefore, rotary shaft biasing portion 159 here corresponds to rotary shaft holder 151 and compression spring 152 in Figure 3. It is also assumed here that the pressures of rotary shaft biasing portions 159R and 159L and pressure member 155 are set to be approximately the same.

[0054] The rotary shaft biasing portions 149 and 159, the pressure members 145 and 155, and the upper frame 161 correspond to a biasing mechanism.

[0055] That is, the elastic layers 150b and 150c of the second cleaning roller 150 and the elastic layer 140b of the first cleaning roller 140 are arranged in a staggered pattern in the longitudinal direction (Y direction) so as to create an overlapping region Sw. In this way, the elastic layer 140b of the first cleaning roller 140 and the elastic layers 150b, 150c of the second cleaning roller 150 do not individually cover the entire maximum paper width Aw in the specifications, and are arranged so that there is one or more elastic layers 140b and 150b, 150c, respectively.

[0056] Here, we will consider the general process that occurs when an unfixed recording paper 1001 onto which a toner image has been transferred is heated and pressed, for example, in the nip portion 120 (Figure 4(a)), with reference to the image forming apparatus 1000.

[0057] When the recording paper 1001 carrying the unfixed toner image after the toner image transfer process in the image forming device 1000 passes through, for example, the nip portion 120 of the fixing device 100 to be fixed, some of the unfixed toner adheres to the fixing belt 110, and if there is no cleaning roller, when the next recording paper 1001 comes into contact with the recording paper, it adheres to the recording paper and becomes a stain.

[0058] On the other hand, if a cleaning roller is provided, unfixed toner adheres to the cleaning roller when passing through the nip of the cleaning roller, and can be removed from the fixing belt (cleaning action).

[0059] 12 is a schematic diagram of a cleaning roller 500 shown as a reference example, which is arranged so that its elastic layer 500b is in pressure contact with the outer peripheral surface of the fixing belt 110, instead of the first cleaning roller 140 and second cleaning roller 150 shown in FIG. 5. Furthermore, in this example, only one cleaning roller 500 is configured to cover the entire maximum paper width.

[0060] In this case, the cleaning action described above is limited to areas where a certain level of nip pressure is applied between the elastic layer 500b of the cleaning roller 500 and the fixing belt 110. If pressure loss occurs for various reasons, such as unevenness in the axial shape or bending of the shaft 500a, the cleaning action does not work in those areas, and dirt will occur.

[0061] In particular, in the case of a small-diameter cleaning roller 500, applying pressure only to both ends can cause the shaft 500a to bend, making it easy for pressure loss to occur in the center of the axial direction. To prevent this, a convex crown can be provided in the center, but this poses problems such as difficulty in manufacturing the crown itself due to the small diameter, and large variations in mass production due to the large ratio of the crown to the diameter, resulting in a lack of stability.

[0062] To address the above-mentioned issues, the fixing device 100 of this embodiment is configured so that the first cleaning roller 140 and the second cleaning roller 150 are pressurized at multiple locations where the shafts 140a, 150a are exposed, thereby forming a uniform nip pressure in the axial direction at the locations where the elastic layers 140b, 150b, 150c are located.

[0063] As described above, the first cleaning roller 140 and the second cleaning roller 150 have exposed shaft portions in addition to their ends, so pressure can be applied in the axial direction at multiple points, allowing uniform nip pressure to be formed even with small diameter rollers.

[0064] Furthermore, by arranging multiple cleaning rollers with similar structures (here, first cleaning roller 140 and second cleaning roller 150) for one fixing belt 110 (cleaned member), it is possible to arrange them so that one or more elastic layers (here, 140b, 150b, 150c) are present across the entire maximum paper width in the axial direction.

[0065] Since the elastic layers 140b, 150b, and 150c are separated in this manner, even if the sliding grease inside the fixing belt 110 leaks and gets around, the grease can be prevented from spreading to other elastic layers, thereby preventing the occurrence of co-rotation problems. This characteristic is particularly useful when an encoder is installed on the shaft of the first cleaning roller 140 or the second cleaning roller 150 to detect the rotation of the fixing belt 110.

[0066] Furthermore, as shown in FIG. 12, in a configuration in which only one cleaning roller 500 covers the entire maximum paper width, when continuous printing is performed in a specific region Pw using recording paper and a printing pattern having this width, toner may accumulate in a specific location on the cleaning roller 500, forming a toner layer 503.

[0067] In this case, the diameter of the area where the toner layer 503 is formed increases by the thickness of the toner layer 503, resulting in a pressure loss area 502 in the area adjacent to the toner layer 503, causing an insufficient cleaning area Ow. However, the area with the toner layer 503 has cleaning ability because it attracts toner well.

[0068] The operation of the fixing device 100 of the first embodiment to address the above-mentioned issues will be described below. Fig. 6 is an explanatory diagram illustrating a case where, for example, specific area Pw1 is continuously printed using recording paper 1001 and a print pattern having this width, and Fig. 7 is an explanatory diagram illustrating a case where, for example, specific area Pw2 is continuously printed using recording paper 1001 and a print pattern having this width.

[0069] As shown in these explanatory drawings, the first cleaning roller 140 and the second cleaning roller 150 have a plurality of elastic layers 140b, 150b, 150c arranged in a staggered pattern and arranged one behind the other in the direction of arrow D, which is the rotational movement direction (circumferential direction) of the fixing belt 110. In this case, in a specific area where the recording paper and the print pattern are continuously printed, the toner layer is formed on the elastic layer that first comes into contact with the outer circumferential surface of the fixing belt 110 that has passed through the nip portion 120, but is not formed in the overlapping portion (overlap area Sw) of the rear elastic layer.

[0070] Therefore, as shown in Figure 6, when the end of the specific region Pw1 is located within the overlap region Sw between the elastic layer 140b and the elastic layer 150b in the axial direction (Y direction), a toner layer 147 is generated in the portion of the two elastic layers 140b of the first cleaning roller 140 within the specific region Pw1, and a toner layer 157 is generated in the portion of the elastic layer 150c located in the center of the second cleaning roller 150 that does not overlap with the two elastic layers 140b.

[0071] In this way, when the end of the toner layer 147 is within the overlap region Sw, the toner layer 147 and pressure-released portions 148 are formed on the elastic layer 140b of the first cleaning roller 140 in the first row, but neither the toner layer 157 nor pressure-released portions are formed on the elastic layer 150b at both ends of the second cleaning roller 150 in the second row, so no poorly cleaned areas are formed in the entire axial direction.

[0072] For example, when borderless printing is performed continuously on A4-sized recording paper having the width of the specific region Pw1, the toner adhering to each elastic layer 140b of the first cleaning roller 140 arranged in the first row on the upstream side in the direction of arrow D becomes noticeable, causing the toner layer 147 to thicken and making it more likely that a pressure-release portion 148 will occur, but the toner adhering to the fixing belt 110 that slips through this pressure-release portion 148 will be removed by the second cleaning roller 150 arranged in the second row on the downstream side.

[0073] On the other hand, when the end of the specific region Pw2 is located closer to the center in the axial direction (Y direction) than the overlap region Sw between the elastic layers 140b and 150b, as shown in Figure 7, a toner layer 147 is generated in the portion of the two elastic layers 140b of the first cleaning roller 140 within the specific region Pw2, and a toner layer 157 is generated in the portion of the elastic layer 150c located in the center of the second cleaning roller 150 that does not overlap with the two elastic layers 140b.

[0074] In this way, when the end of the toner layer 147 is closer to the center than the overlap region Sw, a pressure-depleted portion 148 occurs in the portion of the elastic layer 140b of the first cleaning roller 140 in the first row adjacent to the toner layer 147. However, because the portion behind which the elastic layer 150b of the second cleaning roller 150 is located is cleaned, the poorly cleaned region Bw may be smaller than the pressure-depleted portion 148 depending on the positions of the toner layer 147 and the elastic layer 150b.

[0075] Furthermore, compared to the case of one cleaning roller 500 as shown in FIG. 12, there are many pressure points applied by the pressure member 145, and pressure can be applied near the edge of the toner layer 147, so the range of the pressure-depleted area that occurs is smaller.

[0076] In this embodiment, the fixing device 100 includes the fixing belt 110 and the pressure roller 102, and the first cleaning roller 140 and the second cleaning roller 150 are provided on the fixing belt 110. However, the present invention may also provide these cleaning rollers 140, 150 on the pressure roller 102 side. Furthermore, although the belt-type fixing belt unit 101 is used as the heating means, the present invention can also be applied to a roller-type fixing device. In this case, the opposing member 162 is not necessary.

[0077] In addition, in this embodiment, compression springs 146, 156 are used as the biasing means for the first cleaning roller 140 and the second cleaning roller 150, but the present invention is not limited to this, and any biasing method may be used, such as a torsion spring or a leaf spring, or even a weight attached to the shafts 140a, 150a and biased by the load of the weight.

[0078] In this embodiment, pressure members with different spring strengths, such as pressure member 145 and pressure member 155, are assumed to be provided for the corresponding first cleaning roller 140 and second cleaning roller 150, but the present invention is not limited to this, and any pressure means may be used, such as providing pressure members with the same characteristics in common. For example, if it is expected that a large number of media of a specific width will be printed, it is also possible to adjust the pressure on the first row of cleaning rollers to be higher only in the vicinity of that media width.

[0079] Furthermore, in this embodiment, the elastic layer 140b of the first cleaning roller 140 and the elastic layers 150b, 150c of the second cleaning roller 150 are arranged symmetrically on the left and right sides of the rollers 140, 150, respectively, but they may also be arranged asymmetrically, such as by arranging each elastic layer 140b, 150b only on the left side or only on the right side, or by arranging the same number of elastic layers 140b, 150b alternately.

[0080] As described above, according to the fixing device 100 of this embodiment 1, multiple cleaning rollers (140, 150) are provided on one member to be cleaned (fixing belt 110). Therefore, when a toner layer is formed by continuous printing using recording paper of a specific width and a printing pattern, if the end of the toner layer is in the overlapping portion (overlapping area Sw) of the elastic layer, no toner layer is formed on the rear elastic layer, and therefore it is possible to prevent the occurrence of poorly cleaned areas along the entire axial direction.

[0081] Furthermore, according to the fixing device 100 of the first embodiment, even if the edge of the toner layer is located outside the overlapping portion (overlapping region Sw), if an elastic layer is present behind the pressure-release portion, the poorly cleaned region can be narrowed accordingly. Furthermore, because pressure can be applied by the exposed portion of the shaft at locations other than both ends of the cleaning roller, pressure can be applied near the toner layer compared to a configuration in which a single cleaning roller covers the entire maximum paper width, and the area of ​​the pressure-release portion caused by the toner layer can be kept small.

[0082] Embodiment 2 FIG. 8 is a schematic plan view illustrating the positional relationship in the longitudinal direction (Y direction) of first cleaning roller 140, third cleaning roller 201, fourth cleaning roller 202, and fifth cleaning roller 203 in the second embodiment according to the present invention.

[0083] The main difference between the cleaning rollers of this embodiment shown in Figure 8 and the cleaning rollers of embodiment 1 shown in Figure 5 is that a third cleaning roller 201, a fourth cleaning roller 202, and a fifth cleaning roller 203 are provided instead of the second cleaning roller 150 (Figure 5).

[0084] Therefore, the same reference numerals are used for the parts of the fixing device employing these cleaning rollers 201, 202, 203 that are common to the fixing device 100 employing the second cleaning roller 150 of the first embodiment, or the drawings are omitted to omit the explanation, and the explanation will focus on the differences. Also, since the essential configuration of the image forming device of this embodiment is common to the essential configuration of the image forming device 1000 of the first embodiment shown in Figure 1 except for the fixing device, Figure 1 will be referenced as necessary.

[0085] In this embodiment, as shown in FIG. 8, the first cleaning roller 140 is arranged in the first row, the third cleaning roller 201 and the fourth cleaning roller 202 are arranged coaxially with the sensor area 220 in between in the second row, and the fifth cleaning roller 203 is arranged in the third row.

[0086] The third cleaning roller 201 in the second row includes a shaft 201a having a length approximately one-third that of the shaft 140a of the first cleaning roller 140 in the first row, one elastic layer 201b, and a pair of pressure holding units 211 equipped with biasing means that rotatably hold both ends of the shaft 201a while restricting axial movement of the shaft 201a and press the elastic layer 201b against the fixing belt 110 (see FIG. 2) with a predetermined pressure. The pressure holding unit 211 is held by an upper frame 161 (see FIG. 4(a)), not shown here, similarly to the pressure member 145 (see FIG. 4(a)), for example.

[0087] Here, the fourth cleaning roller 202 in the same row as the third cleaning roller 201 and the fifth cleaning roller 203 in the third row also have the same configuration as the third cleaning roller 201.

[0088] Furthermore, in the direction of arrow D, which is the rotational movement direction of the fixing belt 110, the two ends of the elastic layer 201b and the elastic layer 202b in the second row that are closer to each other have an overlap area Sw1 with the two ends of the two elastic layers 140b of the first cleaning roller 140 that are farther from each other, and both ends of the elastic layer 203b in the third row are configured to form an overlap area Sw2 with the two ends of the two elastic layers 140b of the first cleaning roller 140 that are closer to each other.

[0089] In the above configuration, when continuous printing is performed using recording paper and a print pattern having this width in specific region Pw1 whose both ends are within a pair of overlapping regions Sw1, toner layer 147 (see FIG. 6) and pressure relief portion 148 (see FIG. 6) are formed on the first row of first cleaning roller 140, but no poorly cleaned region occurs in the entire axial direction. The reason why no poorly cleaned region occurs is the same as that explained with reference to FIG. 6 in the first embodiment, and therefore will not be explained here.

[0090] Similarly, when continuous printing is performed using recording paper and a printing pattern having this width in a specific area Pw2 whose both ends are located closer to the center than the pair of overlapping areas Sw1, a toner layer 147 (see Figure 7) and a pressure-relieved portion 148 (see Figure 7) are formed on the first cleaning roller 140 in the first row, but the portion in the second row at the rear where the elastic layer 201b of the third cleaning roller 201 and the elastic layer 202b of the fourth cleaning roller 202 are located is cleaned.

[0091] Therefore, depending on the positions of toner layer 147 (see FIG. 7) and elastic layers 201b and 202b, poorly cleaned area Bw (see FIG. 7) may be smaller than pressure-relieved portion 148 (see FIG. 7). The reason for this is the same as that explained with reference to FIG. 7 in the first embodiment, and therefore will not be explained here.

[0092] In this embodiment, in addition to being able to obtain the same effects as in the first embodiment, the sensor area 220 is provided in the center of the width direction of the fixing belt 110, which increases the degree of freedom in layout within the fixing device, for example, by allowing a temperature sensor for the fixing belt 110 to be placed in this area. Furthermore, the cleaning rollers from the second row onwards are configured to be divided into smaller units, which also increases the degree of freedom in layout of these rollers.

[0093] Embodiment 3 FIG. 9(a) is a schematic plan view illustrating the positional relationship between the sixth cleaning roller 301 and the seventh cleaning roller 302 in the third embodiment according to the present invention.

[0094] The main difference between the cleaning rollers of this embodiment shown in Figure 9(a) and the cleaning rollers of embodiment 1 shown in Figure 5 is that the sixth cleaning roller 301 and the seventh cleaning roller 302 each include one elastic layer. Therefore, parts of the fixing device employing the sixth cleaning roller 301 and the seventh cleaning roller 302 that are common to the fixing device 100 of embodiment 1 described above will be denoted by the same reference numerals or will not be shown in the drawings, and the description will focus on the differences. Furthermore, since the essential configuration of the image forming apparatus of this embodiment is common to the essential configuration of the image forming apparatus 1000 of embodiment 1 shown in Figure 1 except for the fixing device, Figure 1 will be referenced as necessary.

[0095] In this embodiment, as shown in FIG. 9(a), the sixth cleaning roller 301 in the first row has a shaft 301a that extends beyond the specified maximum paper width Aw in the width direction (arrow Y direction) of the fixing belt 110, and a roller-shaped elastic layer 301b that extends centrally within the specified maximum paper width Aw and is formed to cover the shaft 301a, and the seventh cleaning roller 302 in the second row has a shaft 302a and elastic layer 302b that also extend beyond the specified maximum paper width Aw.

[0096] The right end of the shaft 301a is held by the right support lever 103R (see FIG. 3) via a rotary shaft biasing part 311R including the rotary shaft holding part 141R and the compression spring 142R described with reference to FIG. 3 in the first embodiment, and the left end is similarly supported by the left support lever 103L. Furthermore, pressure members 345 are provided in positions corresponding to the shaft 301a on which the elastic layer 301b is not formed and facing both ends of the elastic layer 301b.

[0097] Similarly, the right end of shaft 302a is held by right support lever 103R (see Figure 3) via a rotary shaft biasing portion 312R equipped with rotary shaft holding portion 151R and compression spring 152R as described with reference to Figure 3 in embodiment 1, and the left end is similarly supported by left support lever 103L via rotary shaft biasing portion 312L.

[0098] 9(b), the horizontal axis represents the axial position (direction of arrow Y) of the sixth cleaning roller 301 and the seventh cleaning roller 302, and the vertical axis represents the pressure applied to the fixing belt 110 by the elastic layer 301b of the sixth cleaning roller 301 and the elastic layer 302b of the seventh cleaning roller 302. In FIG. 9(b), the dashed-dotted line represents the distribution of pressure Pa by the elastic layer 301b, and the dotted line represents the distribution of pressure Pb by the elastic layer 302b.

[0099] As shown in Figure 9(b), at the maximum specified paper width Aw, the pressure Pa from the elastic layer 301b has the characteristic that no pressure is generated at the ends and the pressure peaks in the center due to the limited area of ​​action of the elastic layer 301b and the action of the pressure member 345, and the pressure Pb from the elastic layer 302b has the characteristic that it is strong at both ends and weak in the center because the shaft 302a is held and pressurized only at both ends by the pair of rotary shaft biasing members 312R, 312L.

[0100] Therefore, the total pressure Pt, which is the sum of the pressures Pa and Pb, is a pressure that complements the pressures Pa and Pb at both ends and the center of the maximum paper width Aw in the specifications. Ideally, it is desirable to adjust the pressure distribution of the pressures Pa and Pb by adjusting the shape (position and length of the elastic layer, etc.) and characteristics (bias force of the pressure member 345, etc.) of each member so that the total pressure Pt is approximately constant across the maximum paper width Aw in the specifications.

[0101] As described above, according to the fixing device of this embodiment, even when the device width is small and there is no space to install multiple elastic layers and pressure members, pressure loss can be prevented in the entire axial direction, and cleaning capability can be provided over the entire maximum paper width in the axial direction.

[0102] Embodiment 4 FIG. 10 is a schematic plan view illustrating the positional relationship in the width direction (arrow Y direction) of the first cleaning roller 140, the second cleaning roller 150, the main heater 171, the two sub-heaters A 172, and the two sub-heaters B 173 in the fourth embodiment of the present invention.

[0103] The fixing device of this embodiment shown in FIG. 10 differs from, for example, fixing device 100 of embodiment 1 shown in FIG. 5 in that heater 113 shown in FIG. 4(b) is separated into a main heater 171, two sub-heaters A172 arranged on either side of main heater 171, and two sub-heaters B173 arranged on either side of main heater 171. Therefore, parts common to fixing device 100 of embodiment 1 described above in the fixing device employing main heater 171, two sub-heaters A172, and two sub-heaters B173 are denoted by the same reference numerals or omitted from the drawings, and the following description focuses on the differences. Furthermore, the essential configuration of the image forming apparatus of this embodiment is common to the essential configuration of image forming apparatus 1000 of embodiment 1 shown in FIG. 1, except for the fixing device, and therefore FIG. 1 will be referenced as necessary.

[0104] As shown in Figure 10, here, the main heater 171 as the first heating element is arranged in an area corresponding to the first heating area in the center of the maximum paper width Aw in the specifications, two sub-heaters A172 as the second heating element are arranged in areas corresponding to the second heating areas continuous with both side ends thereof, and two further sub-heaters B173 are arranged in areas continuous with both side ends thereof.

[0105] The overlapping region Sw is located outside the boundary where the main heater 171 and the sub-heater A 172 meet, and is set to include at least the boundary where the sub-heater A 172 and the sub-heater B 173 meet in the longitudinal direction. Here, the boundary position coincides with the outer edge of the overlapping region Sw. The main heater 171, the two sub-heaters A 172, and the two sub-heaters B 173 are arranged in the same positions as the heater 113 shown in FIG. 4.

[0106] In the above configuration, when recording paper having this width is printed in the specific region Pw as shown in Fig. 10, the edge of the paper is within the region of the sub-heater A172, so the adjacent main heater 171 and sub-heater A172 are individually temperature controlled. In this case, because the heaters are controlled to heat according to the paper passing portion, the temperature rises excessively in the non-paper passing portion within the heating width of the sub-heater A172 because there is no heat absorption by the passing recording paper, and the temperature rises outside the paper width (corresponding to the specific region Pw) within the heating width. Therefore, in this embodiment, as shown in Fig. 10, the non-paper passing portion of the sub-heater A172 is configured to be included in the overlap region Sw in the width direction.

[0107] As described above, by configuring the non-sheet-passing area of ​​the sub-heater A172, which is prone to temperature rise, to overlap with the overlapping area Sw, this overlapping area suppresses the temperature rise in the non-sheet-passing area, and prevents the fixing belt 110 from reaching a temperature that exceeds its heat resistance. This reduces damage to the fixing belt 110 and deterioration of throughput due to control performed to protect the fixing belt when the temperature rises excessively, such as during idling operation or slowing down the conveying speed.

[0108] Embodiment 5. FIG. 11 is a schematic plan view illustrating the positional relationship in the width direction (direction of arrow Y) of first cleaning roller 240, second cleaning roller 150, main heater 171, and two sub-heaters A 172 in the fifth embodiment according to the present invention.

[0109] The fixing device of this embodiment shown in FIG. 11 differs from, for example, fixing device 100 of Embodiment 1 shown in FIG. 5 in that heater 113 shown in FIG. 4(b) is separated into main heater 171 and two sub-heaters A172 arranged on either side of it, and the configuration of first cleaning roller 240 is different from that of first cleaning roller 140 shown in FIG. 5. Therefore, parts common to fixing device 100 of Embodiment 1 described above in the fixing device employing main heater 171, two sub-heaters A172, and first cleaning roller 240 are denoted by the same reference numerals or omitted from the drawings, and the description will focus on the differences. Furthermore, since the essential configuration of the image forming apparatus of this embodiment is common to the essential configuration of image forming apparatus 1000 of Embodiment 1 shown in FIG. 1 except for the fixing device, reference will be made to FIG. 1 as necessary.

[0110] As shown in Figure 11, here, the main heater 171 as the first heating element is arranged in an area corresponding to the first heating area in the center of the maximum paper width Aw specified in the specifications, and two sub-heaters A172 as the second heating elements are arranged in areas corresponding to the second heating areas continuing from both side ends thereof.

[0111] The boundary where the main heater 171 and the sub-heater A 172 meet is located within the overlapping region Sw, and the outer ends of the elastic layers 240b of the first cleaning roller 240 and the elastic layers 150b of the second cleaning roller 150 that form the overlapping region Sw extend beyond at least the outer ends of the sub-heaters A 172. Here, the outer ends are aligned.

[0112] For this reason, the pair of pressure members 145 arranged to face the outer end portions of each elastic layer 140b shown in Fig. 5 of the first embodiment are omitted here. The main heater 171 and two sub-heaters A 172 are arranged in the same positions as the heater 113 shown in Fig. 4, instead of the heater 113.

[0113] 11, when recording paper having this width is printed in the specific region Pw, the edge of the paper is within the region of the sub-heater A172, so the adjacent main heater 171 and sub-heater A172 are individually temperature controlled. In this case, because the heaters are controlled to heat in accordance with the paper passing area, the temperature rises excessively in the non-paper passing areas within the heating width of the sub-heater A172 because there is no heat absorption by the passing recording paper, and the temperature rises outside the paper width (corresponding to the specific region Pw) within the heating width.

[0114] Therefore, in this embodiment, the non-sheet passing portion of the sub-heater A172 is configured to be included in the overlapping region Sw in the width direction, as shown in Fig. 11. Furthermore, in each overlapping region Sw, the length d1 of the sub-heater A172 portion is configured to be longer than the length d2 of the main heater 171 portion.

[0115] As described above, by configuring the non-sheet-passing area of ​​the sub-heater A172, which is prone to temperature rise, to overlap with the overlapping area Sw, this overlapping area suppresses the temperature rise in the non-sheet-passing area, and prevents the fixing belt 110 from reaching a temperature that exceeds its heat resistance. This reduces damage to the fixing belt 110 and deterioration of throughput due to control performed to protect the fixing belt when the temperature rises excessively, such as during idling operation or slowing down the conveying speed.

[0116] In the above claims and explanation of the embodiments, terms such as "upper," "lower," "left," "right," "front," and "rear" are used for convenience and do not limit the absolute positional relationship when the fixing device is arranged. [Industrial Applicability]

[0117] In the above embodiment, an example was shown in which the present invention is applied to an image forming apparatus as a color printer, but the present invention is not limited to this and can also be applied to image processing apparatuses such as copiers, facsimiles, MFPs, etc. Also, although a color printer has been described, a monochrome printer may also be used. [Explanation of symbols]

[0118] 100 fixing device, 101 fixing belt unit, 102 pressure roller, 102a rotating shaft, 103R right support lever, 103L left support lever, 104R right inner guide portion, 105R right regulating portion, 106R right guide member, 107 heater unit, 110 fixing belt, 111 stay, 112 heater holder, 113 heater, 114 heat diffusion plate, 115R right rotating shaft hole, 116R right spring receiving portion, 117R right abutment flat portion, 120 nip portion, 131R right rotating fulcrum, 140 first cleaning roller, 140a shaft, 140b elastic layer, 141R rotating shaft holding portion, 142R compression spring, 145 pressure member, 145a Axis pressure portion, 145b Arm portion, 146 Compression spring, 147 Toner layer, 148 Pressure release portion, 149 Rotation shaft biasing portion, 150 Second cleaning roller, 150a Shaft, 150b Elastic layer, 150c Elastic layer, 151R Rotation shaft holding portion, 152R Compression spring, 155 Pressure member, 155a Axis pressure portion, 155b Arm portion, 156 Compression spring, 157 Toner layer, 159 Rotation shaft biasing portion, 161 Upper frame, 161a First holding portion, 161b Second holding portion, 162 Opposing member, 201 Third cleaning roller, 201a Shaft, 201b Elastic layer, 171 Main heater, 172 Sub heater A, 173 Sub-heater B, 202 Fourth cleaning roller, 202b Elastic layer, 203 Fifth cleaning roller, 203b Elastic layer, 240 First cleaning roller, 240b Elastic layer, 211 Pressure holding portion, 301 Sixth cleaning roller, 301a Shaft, 301b Elastic layer, 302 Seventh cleaning roller, 302a Shaft, 302b Elastic layer, 311R Rotary shaft biasing portion, 312R Rotary shaft biasing portion, 345 Pressure member, 500 Cleaning roller, 500a Shaft, 500b Elastic layer, 502 Pressure release portion, 503 Toner layer, 1000 Image forming apparatus, 1001 Recording paper, 1004 Paper feed cassette, 1005 Paper feed roller, 1006 Registration roller pair, 1010 developing device, 1011 photosensitive drum, 1012Charging device, 1013 exposure device, 1014 developer supply device, 1015 cleaning device, 1020 transfer device, 1021 endless transfer belt, 1022 drive roller, 1023 tension roller, 1030 transport roller, 1031 transport roller, 1032 paper discharge stacking section.

Claims

1. a first rotor extending in a first direction; a plurality of cleaning members arranged in a circumferential direction of the first rotating body, the cleaning members including elastic bodies that come into contact with the first rotating body to clean it; a biasing mechanism that biases the plurality of cleaning members toward the first rotating body; Equipped with The plurality of cleaning members include: a first cleaning member including a first support and a first elastic body supported by the first support; a second cleaning member including a second support and a second elastic body supported by the second support; and a second contact area where the second elastic body contacts the first rotating body in the first direction has an overlap area where the second elastic body contacts the first rotating body and the first contact area where the first elastic body contacts the first rotating body, the overlapping area includes a position corresponding to an end in the width direction of a medium of a predetermined standard size to be subjected to fixing processing, The biasing mechanism has a biasing member that applies a biasing force to the first support body in a region different from the overlap region. A fixing device characterized by:

2. a first heating member that heats a first heating region of the first rotating body in the first direction; a second heating member that heats a second heating region of the first rotating body in the first direction, the second heating region being continuous with an end of the first heating region; and In the first direction, the overlapping region is provided outside a position corresponding to a boundary between the first heating region and the second heating region, and includes a range of the second heating member.

2. The fixing device according to claim 1, wherein the fixing device is a fixing device for fixing a toner image on the toner image.

3. a first heating member that heats a first heating region of the first rotating body in the first direction; a second heating member that heats a second heating region of the first rotating body in the first direction, the second heating region being continuous with an end of the first heating region; and 2. The fixing device according to claim 1, wherein the overlapping region includes a position corresponding to a boundary between the first heating region and the second heating region in the first direction.

4. 4. The fixing device according to claim 3, wherein the overlapping region includes a range of the second heating member in the first direction.

5. 4. The fixing device according to claim 3, wherein the length of the overlapping region on the side of the second heating region is longer than the length of the overlapping region on the side of the first heating region.

6. 2. The fixing device according to claim 1, wherein the biasing force applied to the first support by the biasing mechanism is stronger at the center side than at the end sides in the first direction.

7. the second cleaning member has a third elastic body supported by the second support body with a gap between the third elastic body and the second elastic body; the first contact region includes a region corresponding to the gap in the first direction; 2. The fixing device according to claim 1, wherein the biasing mechanism further comprises a biasing member that applies a biasing force to the second support member in the gap.

8. 3. An image forming apparatus comprising the fixing device according to claim 1.

Images