Patent Publication Number: US-11392067-B2

Title: Fixing device including plural nip pads

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 16/729,693, filed Dec. 30, 2019, which claims priority from Japanese Patent Application No. 2019-030313 and Japanese Patent Application No. 2019-030311 both of which were filed on Feb. 22, 2019, as well as Japanese Patent Application No. 2019-062290 filed on Mar. 28, 2019. The content of the aforementioned applications is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     Aspects of the disclosure relate to a fixing device including a rotator and a belt, and an image forming apparatus including the fixing device. 
     BACKGROUND 
     A known image forming apparatus includes a fixing device. The fixing device includes a heat roller, a belt, an upstream pad, a downstream pad, a pad holder, a first stay, a second stay, and springs. The upstream pad and the downstream pad press the belt against the heat roller, thus forming a nip. The pad holder holds the upstream pad and the downstream pad. The first stay and the second stay support the pad holder. The springs urge the first stay and the second stay toward the heat roller. The fixing device fixes a toner image onto a sheet passing through the nip by heating and melting toner on the sheet and applying pressure to the sheet. 
     SUMMARY 
     According to one aspect of the disclosure, a device includes a rotator, a belt, a first pad, a second pad, a stay, a holder, and an urging member. The belt faces the rotator and has an outer peripheral surface which is configured to contact the rotator to form a nip therebetween. The first pad is configured to press the belt toward the rotator to form one part of the nip. The second pad is configured to press the belt toward the rotator, to form another part of the nip. The holder holds the first pad and the second pad. The stay supports the holder. The urging member urges the stay toward the rotator in an urging direction. The second pad is located upstream of the first pad in a conveyance direction in the nip orthogonal to the urging direction. At least a portion of a contact area between the stay and the holder is located downstream of a center of the nip and upstream of a front edge of the first pad in the conveyance direction. 
     According to another aspect of the disclosure, a fixing device includes a roller, a heater, a belt, a first pad, a second pad, a holder, and a stay. The roller has a rotation axis extending in an axial direction. The heater is positioned within the roller. The belt faces the roller and has an outer peripheral surface which is configured to contact the roller to form a nip therebetween. The first pad is configured to press the belt toward the roller to form one part of the nip. The second pad is configured to press the belt toward the rotator, to form another part of the nip. The holder holds the first pad and the second pad. The stay supports the holder. The stay receives an urging force urging the stay toward the rotator in an urging direction. The second pad is located upstream of the first pad in a conveyance direction in the nip orthogonal to the urging direction and the axial direction. A contact area between the stay and the holder is located entirely downstream of the second pad and at least partially upstream of the first pad in the conveyance direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross sectional view of an image forming apparatus including a fixing device according to a first embodiment of the disclosure. 
         FIG. 2  is a cross sectional view of the fixing device illustrated in  FIG. 1 . 
         FIG. 3  is a cross sectional view of the fixing device taken along a line X 1 -X 1  of  FIG. 2 . 
         FIG. 4  is a side sectional view of the fixing device illustrated in  FIG. 1 . 
         FIG. 5A  illustrates a process of manufacturing the fixing device illustrated in  FIG. 2 , wherein upstream and downstream pads are to be attached to a holder. 
         FIG. 5B  illustrates process of measuring a dimension between an upper front edge of the downstream pad illustrated in  FIG. 5A  and a reference surface of a holder protrusion. 
         FIG. 6  is an exploded perspective view of the holder of the fixing device illustrated in  FIG. 2  to be attached to side frames. 
         FIG. 7  is a perspective view of the fixing device illustrated in  FIG. 2 . 
         FIG. 8  is a side sectional view of a fixing device according to a first variation of the first embodiment. 
         FIG. 9  is a perspective view of a side frame and a bracket in a fixing device according to a second variation of the first embodiment. 
         FIG. 10  is a cross sectional view of a fixing device according to a second embodiment of the disclosure. 
         FIG. 11  is an enlarged cross sectional view of a downstream pad and an upstream pad in the fixing device illustrated in  FIG. 10 . 
         FIG. 12  is a front view of the fixing device illustrated in  FIG. 10  from which a heat roller, a belt, and a sliding sheet are omitted. 
         FIG. 13  is a cross sectional view taken along a line X 2 -X 2  of  FIG. 12 . 
         FIG. 14  is a cross sectional view taken along a line X 3 -X 3  of  FIG. 12 . 
         FIG. 15  is a cross sectional view taken along a line X 4 -X 4  of  FIG. 12 . 
     
    
    
     DETAILED DESCRIPTION 
     1. Overview of Image Forming Apparatus 
     As illustrated in  FIG. 1 , a fixing device  1  is disposed in an image forming apparatus  100 . An overview of the image forming apparatus  100  will be described. 
     The image forming apparatus  100  includes a photosensitive drum  101 , a charger  102 , a laser scan unit  103 , a developing roller  104 , a transfer roller  105 , the fixing device  1 , a sheet feed mechanism  106 , a sheet feed tray  107 , and a sheet discharge tray  108 . 
     The charger  102  charges a surface of the photosensitive drum  101 . The laser scan unit  103  exposes the surface of the photosensitive drum  101  charged by the charger  102 . The surface of the photosensitive drum  101  thus carries an electrostatic latent image thereon. The developing roller  104  supplies toner to the surface, having the electrostatic latent image thereon, of the photosensitive drum  101 . The surface of the photosensitive drum  101  thus carries a toner image thereon. The sheet feed mechanism  106  feeds a sheet from the sheet feed tray  107  toward between the photosensitive drum  101  and the transfer roller  105 . The transfer roller  105  transfers the toner image on the surface of the photosensitive drum  101  onto the sheet. The fixing device  1  fixes the toner image onto the sheet by heating and melting toner and applying pressure to the sheet. After passing through the fixing device  1 , the sheet is discharged onto the sheet discharge tray  108 . 
     2. Detailed Description of Fixing Device 
     As illustrated in  FIGS. 1-3 , the fixing device  1  includes a heat roller  2  as an example of a rotator, a belt  3 , a downstream pad  4  as an example of a first pad, an upstream pad  5  as an example of a second pad, a holder  6 , a downstream fixing plate  66 , an upstream fixing plate  67 , a stay  68 , urging members  69 , a pair of side frames  7 L,  7 R, two bearings  11 ,  12 , a pair of brackets  9 L,  9 R, and screws  14 . 
     2.1 Heat Roller  2   
     As illustrated in  FIG. 1 , the heat roller  2  heats a sheet having a toner image thereon when the sheet passes through between the heat roller  2  and the belt  3 . The heat roller  2  contacts a surface of the sheet on which the toner image has been transferred. The heat roller  2  extends in a first direction. The heat roller  2  is rotatable about a rotation axis extending in the first direction. The heat roller  2  is driven to rotate to convey a sheet. The heat roller  2  includes a roller body  20  and a heater  21 . The roller body  20  is of cylindrical shape extending in the first direction. The heater  21  heats the roller body  20 . The heater  21  is a halogen heater. The heater  21  is located in the roller body  20 . The heater  21  extends in the first direction. 
     2.2 Belt  3   
     As illustrated in  FIG. 2 , the belt  3  faces the heat roller  2  in a second direction. The second direction is orthogonal to the first direction. The second direction is one of radial directions of the heat roller  2 . The belt  3  contacts the heat roller  2 . The second direction is orthogonal to a conveyance direction in a nip N where the heat roller  2  and the belt  3  contact each other. The second direction is a direction where the urging members  69  urge the stay  68  toward the heat roller  2 . The conveyance direction in the nip N is a direction where a sheet passes through between the heat roller  2  and the belt  3  and is similar to a rotation direction of the heat roller  2  in the nip N. The nip N will be described later. The belt  3  extends in the first direction. The belt  3  is of cylindrical shape. The belt  3  is heat resistant and flexible. The belt  3  is made of polyimide resin. 
     2.3 Downstream Pad  4   
     As illustrated in  FIG. 2 , the downstream pad  4  presses a sheet having a toner image thereon when the sheet passes through between the heat roller  2  and the belt  3 . The downstream pad  4  presses the belt  3  toward the heat roller  2 . The downstream pad  4  is disposed within an interior space of the belt  3 . The downstream pad  4  is disposed downstream of the upstream pad  5  in the conveyance direction in the nip N. The downstream pad  4  is harder than the upstream pad  5 . The downstream pad  4  is an elastic member made of rubber. The downstream pad  4  extends in the first direction. The downstream pad  4  is of rectangular shape when viewed in the first direction. The downstream pad  4  has an upper front edge  40 , an upper rear edge  41 , a lower front edge  42 , and a lower rear edge  43 . The upper front edge  40  and the upper rear edge  41  are located to the heat roller  2  in the second direction. The lower front edge  42  and the lower rear edge  43  are located opposite to the heat roller  2  relative to the upper front edge  40  and the upper rear edge  41 . 
     The upper front edge  40  and the upper rear edge  41  are spaced from each other in a third direction. The third direction is orthogonal to the first direction and the second direction. The third direction extends in the conveyance direction in the nip N. The third direction is a direction in the nip N directed from upstream toward downstream in the conveyance direction. The upper front edge  40  is located upstream of the upper rear edge  41  in the third direction. The upper front edge  40  brings the belt  3  into contact with the heat roller  2 . More specifically, the upper front edge  40  brings the belt  3  into contact with the heat roller  2 , forming a downstream nip N 1 . The upper rear edge  41  does not bring the belt  3  into contact with the heat roller  2 . The upper front edge  40  contacts the belt  3 . The upper front edge  40  and the heat roller  2  pinch a portion of the belt  3  therebetween. The upper rear edge  41  is spaced from the belt  3 . 
     The lower front edge  42  and the lower rear edge  43  are spaced from each other in the third direction. The lower front edge  42  is located upstream of the lower rear edge  43  in the third direction. 
     The downstream pad  4  has an upstream end surface  44  and a downstream end surface  45  in the third direction. The upstream end surface  44  is located upstream of the downstream end surface  45  in the third direction. The upstream end surface  44  and the downstream end surface  45  are spaced from each other in the third direction. The upstream end surface  44  is located between the upper front edge  40  and the lower front edge  42 . The downstream end surface  45  is located between the upper rear edge  41  and the lower rear edge  43 . 
     2.4 Upstream Pad  5   
     As illustrated in  FIG. 2 , the upstream pad  5  presses a sheet having a toner image thereon when the sheet passes through between the heat roller  2  and the belt  3 . The upstream pad  5  presses the belt  3  toward the heat roller  2 . More specifically, at least a portion of the downstream pad  4  and at least a portion of the upstream pad  5  press the belt  3  toward the heat roller  2 . The upstream pad  5  is disposed upstream of the downstream pad  4  in the third direction. The upstream pad  5  is softer than the downstream pad  4 . The upstream pad  5  is an elastic member made of rubber. The upstream pad  5  extends in the first direction. The upstream pad  5  is of rectangular shape when viewed in the first direction. 
     The upstream pad  5  has an upstream portion  50  and a downstream portion  51 . The upstream portion  50  is located upstream of the downstream portion  51  in the third direction. The upstream portion  50  does not bring the belt  3  into contact with the heat roller  2 . The downstream portion  51  brings the belt  3  into contact with the heat roller  2 . The upstream portion  50  is spaced from the belt  3 . The downstream portion  51  contacts the belt  3 . The downstream portion  51  and the heat roller  2  pinch a portion of the belt  3  therebetween. 
     The upstream pad  5  has an upper front edge  54 , an upper rear edge  55 , a lower front edge  56 , and a lower rear edge  57 . The upper front edge  54  and the upper rear edge  55  are located to the heat roller  2  in the second direction. The lower front edge  56  and the lower rear edge  57  are located opposite to the heat roller  2  relative to the upper front edge  54  and the upper rear edge  55 . 
     The upper front edge  54  is located upstream of the upper rear edge  55  in the third direction. The lower rear edge  57  is located downstream of the lower front edge  56  in the third direction. The upper front edge  54  does not bring the belt  3  into contact with the heat roller  2 . The upper rear edge  55  brings the belt  3  into contact with the heat roller  2 . More specifically, the upper rear edge  55  brings the belt  3  into contact with the heat roller  2 , forming an upstream nip N 2 . The upper front edge  54  is spaced from the belt  3 . The upper rear edge  55  contacts the belt  3 . The upper rear edge  55  and the heat roller  2  pinch a portion of the belt  3  therebetween. 
     In other words, the upper front edge  40  of the downstream pad  4  and the upper rear edge  55  of the upstream pad  5  press the belt  3  toward the heat roller  2 . The belt  3  thus contacts the heat roller  2  in a range from a portion of the belt  3  pinched between the upper rear edge  55  and the heat roller  2  and a portion of the belt  3  pinched between the upper front edge  40  and the heat roller  2 , thus forming the nip N. In other words, the nip N ranges in the third direction from an upstream end of the upstream nip N 2  to a downstream end of the downstream nip N 1 . The nip N is where the heat roller  2  and the belt  3  contact each other. 
     The upstream pad  5  has an upstream end surface  52  and a downstream end surface  53  in the third direction. The upstream end surface  52  is located upstream of the downstream end surface  53  in the third direction. The upstream end surface  52  and the downstream end surface  53  are spaced from each other in the third direction. The upstream portion  50  includes the upstream end surface  52 . The upstream end surface  52  is located between the upper front edge  54  and the lower front edge  56 . The downstream portion  51  includes the downstream end surface  53 . The downstream end surface  53  is located between the upper rear edge  55  and the lower rear edge  57 . 
     2.5 Holder  6   
     As illustrated in  FIGS. 2 and 3 , the holder  6  holds the downstream pad  4  via the downstream fixing plate  66 . The holder  6  holds the upstream pad  5  via the upstream fixing plate  67 . The holder  6  includes a holder body  60  and holder protrusions  61 ,  62 . 
     As illustrated in  FIG. 2 , the holder body  60  supports the downstream pad  4  and the upstream pad  5 . The holder body  60  is disposed within the interior space of the belt  3 . The holder body  60  extends in the first direction. The holder body  60  includes a first recess  63  and a second recess  64 . The first recess  63  is located downstream of the second recess  64  in the third direction. 
     The first recess  63  receives therein the downstream pad  4  and the downstream fixing plate  66 . The first recess  63  is recessed away from the heat roller  2  in the second direction. The first recess  63  extends in the first direction. The first recess  63  includes a restriction surface  63 A and an inner side surface  63 B. In other words, the holder  6  includes the restriction surface  63 A. The restriction surface  63 A restricts movement of the downstream pad  4  in the third direction. The restriction surface  63 A contacts the downstream end surface  45  of the downstream pad  4  in the third direction to restrict the downstream movement of the downstream pad  4  in the third direction. In other words, the restriction surface  63 A contacts the downstream end surface  45  from a downstream side in the third direction. The restriction surface  63 A is located opposite to the second recess  64  relative to the downstream pad  4 . The inner side surface  63 B is located between the downstream pad  4  and the second recess  64  in the third direction. 
     The second recess  64  receives therein the upstream pad  5  and the upstream fixing plate  67 . The second recess  64  is recessed away from the heat roller  2  in the second direction. The second recess  64  extends in the first direction. The second recess  64  includes a restriction surface  64 A and an inner side surface  64 B. The restriction surface  64 A restricts movement of the upstream pad  5  in the third direction. The restriction surface  64 A contacts the upstream end surface  52  of the upstream pad  5  in the third direction to restrict the upstream movement of the upstream pad  5  in the third direction. In other words, the restriction surface  64 A contacts the upstream end surface  52  from an upstream side in the third direction. The restriction surface  64 A is located opposite to the first recess  63  relative to the upstream pad  5 . The inner side surface  64 B is located between the upstream pad  5  and the first recess  63  in the third direction. 
     As illustrated in  FIG. 3 , the holder protrusions  61 ,  62  sandwich therebetween the holder body  60  in the first direction. The holder body  60  includes a first end portion  60 A and a second end portion  60 B opposite to the first end portion  60 A in the first direction. The holder protrusion  61  protrudes from the first end portion  60 A of the holder body  60  in the first direction. The holder protrusion  62  protrudes from the second end portion  60 B of the holder body  60  in the first direction. The holder protrusions  61 ,  62  are of square tubular shape. 
     2.6 Downstream Fixing Plate  66   
     As illustrated in  FIG. 2 , the downstream fixing plate  66  is disposed in the first recess  63 . The downstream fixing plate  66  extends in the first direction. The downstream fixing plate  66  may be made of a material harder than that of the downstream pad  4 , for example, metal or resin. The downstream fixing plate  66  contacts a bottom surface of the first recess  63 . The downstream fixing plate  66  is located upstream relative to the downstream pad  4  in the second direction. The downstream pad  4  is fixedly bonded to the downstream fixing plate  66 . The downstream fixing plate  66  is located upstream relative to the downstream end surface  45  of the downstream pad  4  in the third direction. The downstream fixing plate  66  includes a downstream end  661  and an upstream end  662  located upstream relative to the downstream end  661  in the third direction. The downstream end  661  faces and is spaced from the restriction surface  63 A in the third direction. The downstream end  661  is located opposite to the restriction surface  63 A relative to the downstream end surface  45  in the third direction. The upstream end  662  faces the inner side surface  63 B in the third direction. 
     2.7 Upstream Fixing Plate  67   
     The upstream fixing plate  67  is disposed in the second recess  64 . The upstream fixing plate  67  extends in the first direction. The upstream fixing plate  67  may be made of the same material as that of the downstream fixing plate  66 . The upstream fixing plate  67  contacts a bottom surface of the second recess  64 . The upstream fixing plate  67  is located upstream relative to the upstream pad  5  in the second direction. The upstream pad  5  is fixedly bonded to the upstream fixing plate  67 . The upstream fixing plate  67  is located downstream relative to the upstream end surface  52  of the downstream pad  5  in the third direction. The upstream fixing plate  67  includes a downstream end  671  and an upstream end  672  located upstream relative to the downstream end  671  in the third direction. The downstream end  671  faces the inner side surface  64 B in the third direction. The upstream end  672  faces and is spaced from the restriction surface  64 A in the third direction. The upstream end  672  is located opposite to the restriction surface  64 A relative to the upstream end surface  52  in the third direction. 
     2.8 Stay  68   
     As illustrated in  FIG. 2 , the stay  68  supports the holder  6 . The stay  68  is located opposite to the heat roller  2  relative to the holder  6  in the second direction. The stay  68  contacts the holder  6 . The stay  68  extends in the second direction. The stay  68  includes a first end surface  68 A and a second end surface  68 B opposite to the first end surface  68 A in the second direction. The first end surface  68 A extends in the first direction and the third direction. The first end surface  68 A contacts the holder  6 . A contact area A between the stay  68  and the holder  6  is located downstream of a center B of the nip N and upstream of a center C of the downstream pad  4  in the third direction. The contact area A is located between the center B of the nip N and the center C of the downstream pad  4  in the third direction. The contact area A is located closer to the downstream pad  4  than to the upstream pad  5  in the third direction. The stay  68  is disposed at a position different from the downstream pad  4  in the third direction. The contact area A is located upstream relative to the upper front edge  40  in the third direction. The contact area A is located upstream relative to and away from the upstream end surface  44  in the third direction. The contact area A is located downstream relative to and away from the center B of the nip N in the third direction. 
     As illustrated in  FIG. 3 , the stay  68  is urged toward the heat roller  2  by the urging members  69 . The downstream pad  4  and the upstream pad  5  thus press the belt  3  toward the heat roller  2 . The stay  68  may be made of metal. The stay  68  includes a stay body  681  and insertion portions  682 ,  683 . The stay body  681  is located opposite to the heat roller  2  relative to the holder body  60  in the second direction. The stay body  681  contacts the holder body  60 . The stay body  681  is located toward the downstream pad  4  relative to a midpoint between the downstream pad  4  and the upstream pad  5  in the third direction ( FIG. 2 ). The stay body  681  extends in the first direction. The insertion portion  682  protrudes from a first end of the stay body  681  in the first direction. The insertion portion  683  protrudes from a second end of the stay body  681  opposite to the first end in the first direction. The insertion portion  682  is inserted into the holder protrusion  61 . The insertion portion  683  is inserted into the holder protrusion  62 . 
     2.9 Urging Members  69   
     The two urging members  69  apply pressure to the stay  68 . The urging members  69  are spaced from each other in the first direction. Each urging member  69  includes a spring  691  and a contact portion  692 . In other words, the fixing device  1  includes two springs  691 . The springs  691  urge the downstream pad  4  and the upstream pad  5  toward the heat roller  2  via the stay  68 . The springs  691  are helical compression springs each including a plurality of turns of wire. Each contact portion  692  is located at a downstream end of the corresponding urging member  69  in the second direction. Each contact portion  692  contacts a corresponding one of the holder protrusions  61 ,  62  from opposite the heat roller  2  in the second direction. Each urging member  69  has an upstream end in the second direction supported by a corresponding one of the side frames  7 L,  7 R. The urging members  69  thus press the stay  68  toward the heat roller  2  via the stay  68 . 
     2.10 Side Frames  7 L,  7 R and Bearings  11 ,  12   
     As illustrated in  FIG. 3 , the side frames  7 L,  7 R support the heat roller  2 . The side frame  7 L is spaced from the side frame  7 R in the first direction. The side frame  7 L and the side frame  7 R are identical in structure. Hereinafter, the side frame  7 R will be mainly described and the side frame  7 L will be simply described and illustrated or omitted. 
     The side frame  7 R has a plate shape. The side frame  7 R extends orthogonally to the first direction. The side frame  7 R includes a flat surface  72 . The flat surface  72  faces away from a surface of the side frame  7 R facing the side frame  7 L. The flat surface  72  extends orthogonally to the first direction. As illustrated in  FIGS. 4 and 6 , the side frame  7 R includes a first support portion  70 , an opening  71 , a first protrusion  73 , and a second protrusion  74 . The side frame  7 R further includes a pair of screw holes. The screws  14 A are screwed into the respective screw holes. The opening  71  is located between the screw holes in the third direction. 
     The first support portion  70  supports an end portion of the heat roller  2  in the first direction. The first support portion  70  positions the heat roller  2  relative to the side frame  7 R in a radial direction of the heat roller  2 . The heat roller  2  has a first end portion  2 A and a second end portion  2 B opposite to the first end portion  2 A in the first direction. The first support portion  70  in the side frame  7 R supports the first end portion  2 A. The first support portion  70  in the side frame  7 L supports the second end portion  2 B. 
     The first support portion  70  is a hole. The first support portion  70  is circular when viewed in the first direction. The first end portion  2 A is inserted into the first support portion  70  in the side frame  7 R. The second end portion  2 B is inserted into the first support portion  70  in the side frame  7 L. The heat roller  2  thus passes through the side frames  7 R,  7 L in the first direction. The first end portion  2 A has a peripheral surface rotatably supported by the bearing  11 . The second end portion  2 B has a peripheral surface rotatably supported by the bearing  12 . In other words, the bearing  11  rotatably supports the peripheral surface of the first end portion  2 A. The bearing  12  rotatably supports the peripheral surface of the second end portion  2 B. The first support portion  70  in the side frame  7 R supports the first end portion  2 A via the bearing  11 . The first support portion  70  in the side frame  7 L supports the second end portion  2 B via the bearing  12 . 
     The opening  71  is spaced from the first support portion  70  in the second direction. The opening  71  in the side frame  7 R allows insertion of the holder protrusion  61 . The holder protrusion  61  passes through the side frame  7 R in the first direction. The opening  71  in the side frame  7 L allows insertion of the holder protrusion  62 . The holder protrusion  62  passes through the side frame  7 L in the first direction. In the second direction, the opening  71  has a greater dimension than the holder protrusion  61 ,  62 . In the third direction, the opening  71  has a greater dimension than the holder protrusion  61 ,  62 . 
     As illustrated in  FIG. 4 , the first protrusion  73  and the second protrusion  74  protrude from the flat surface  72  in the first direction. The first protrusion  73  and the second protrusion  74  are of cylindrical shape. The first protrusion  73  is located upstream of the holder protrusion  61  in the third direction. The second protrusion  74  is located downstream of the holder protrusion  61  in the third direction. The opening  71  is located between the first protrusion  73  and the second protrusion  74  in the third direction. 
     2.11 Brackets  9 L,  9 R 
     As illustrated in  FIGS. 3 and 4 , the brackets  9 L,  9 R support the holder  6 . The bracket  9 R is located opposite to the side frame  7 L relative to the side frame  7 R in the first direction. The bracket  9 R contacts the flat surface  72  of the side frame  7 R in the first direction. The bracket  9 L is located opposite to the side frame  7 R relative to the side frame  7 L in the first direction. The bracket  9 L contacts the flat surface  72  of the side frame  7 L in the first direction. The bracket  9 L and the bracket  9 R are identical in structure. Hereinafter, the bracket  9 R will be mainly described and the bracket  9 L will be simply described and illustrated or omitted. 
     The bracket  9 R is movable relative to the side frame  7 R in the third direction. More specifically, the bracket  9 R is movable in the third direction before it is secured to the side frame  7 R using the two screws  14 . The bracket  9 R has a plate shape. The bracket  9 R extends orthogonally to the first direction. As illustrated in  FIGS. 4 and 6 , the bracket  9 R includes a second support portion  90 , a first contact portion  91 , and a second contact portion  92 . The bracket  9 R further includes a pair of long holes  93 ,  94 . The screws  14 A are inserted into the respective long holes  93 ,  94 . The long holes  93 ,  94  are long in the third direction. The second support portion  90  is located between the long holes  93 ,  94  in the third direction. 
     The second support portion  90  supports the holder  6  movably in the second direction. The second support portion  90  is a long hole that is long in the second direction. As illustrated in  FIG. 6 , the second support portion  90  communicates with the opening  71  in the first direction. The holder protrusion  61  is inserted into the second support portion  90  of the bracket  9 R. The holder protrusion  62  is inserted into the second support portion  90  of the bracket  9 L. In the second direction, the second support portion  90  has a greater dimension than the holder protrusion  61 ,  62 . 
     As illustrated in  FIG. 4 , the second support portion  90  has contact surfaces  90 A,  90 B. The contact surfaces  90 A,  90 B of the bracket  9 R are contactable with the holder protrusion  61 . The contact surfaces  90 A,  90 B of the bracket  9 L are contactable with the holder protrusion  62 . The contact surfaces  90 A,  90 B face and are spaced from each other in the third direction. The contact surfaces  90 A,  90 B extend in the second direction. 
     The first contact portion  91  contacts the first protrusion  73  in the second direction. The second contact portion  92  contacts the second protrusion  74  in the second direction. The first contact portion  91  is located upstream of the second support portion  90  in the third direction. The second contact portion  92  is located downstream of the second support portion  90  in the third direction. The second support portion  90  is located between the first contact portion  91  and the second contact portion  92  in the third direction. 
     The first contact portion  91  is a long hole that is long in the third direction. The first protrusion  73  is inserted into the first contact portion  91 . The first contact portion  91  has two first guide surfaces  91 A,  91 B. The first guide surface  91 A is spaced from the first guide surface  91 B in the second direction. The first guide surfaces  91 A,  91 B are contactable with the first protrusion  73  to guide the first protrusion  73 . The first guide surfaces  91 A,  91 B extend in the third direction. 
     The second contact portion  92  is a long hole that is long in the third direction. The second protrusion  74  is inserted into the second contact portion  92 . The second contact portion  92  has two second guide surfaces  92 A,  92 B. The second guide surface  92 A is spaced from the second guide surface  92 B in the second direction. The second guide surfaces  92 A,  92 B are contactable with the second protrusion  74  to guide the second protrusion  74 . The second guide surfaces  92 A,  92 B extend in the third direction. 
     The brackets  9 R is thus movable in the third direction with the first protrusion  73  contacting the first contact portion  91 . Similarly, the brackets  9 L is movable in the third direction with the second protrusion  74  contacting the second contact portion  92 . 
     2.12 Screws  14   
     As illustrated in  FIGS. 3 and 4 , the bracket  9 R is secured to the side frame  7 R with two first screws  14 A. The bracket  9 L is secured to the side frame  7 L with two second screws  14 B. One of the first screws  14 A is screwed into a screw hole in the side frame  7 R via the long hole  93  in the bracket  9 R. The other one of the first screws  14 A is screwed into another screw hole in the side frame  7 R via the long hole  94  in the bracket  9 R. One of the second screws  14 B is screwed into a screw hole in the side frame  7 L via the long hole  93  in the bracket  9 L. The other one of the second screws  14 B is screwed into another screw hole in the side frame  7 L via the long hole  94  in the bracket  9 L. 
     3. Process of Manufacturing Fixing Device  1   
     Referring to  FIGS. 5A to 7 , a process of manufacturing the fixing device  1  will be described. 
     As illustrated in  FIG. 5A , to manufacture the fixing device  1 , the downstream pad  4  is bonded to the downstream fixing plate  66 . At that time, the downstream end surface  45  of the downstream pad  4  is located downstream of the downstream end  661  of the downstream fixing plate  66  in the third direction. The upstream end surface  44  of the downstream pad  4  is located between the downstream end  661  and the upstream end  662  of the downstream fixing plate  66  in the third direction. 
     The upstream pad  5  is bonded to the upstream fixing plate  67 . At that time, the upstream end surface  52  of the upstream pad  5  is located upstream of the upstream end  672  of the upstream fixing plate  67  in the third direction. The downstream end surface  53  of the downstream pad  5  is located between a downstream end  671  and the upstream end  672  of the upstream fixing plate  67  in the third direction. 
     The downstream pad  4  and the downstream fixing plate  66  are placed in the first recess  63 . At that time, the downstream end  661  of the downstream fixing plate  66  does not contact the restriction surface  63 A, while the downstream end surface  45  of the downstream pad  4  contacts the restriction surface  63 A. 
     The upstream pad  5  and the upstream fixing plate  67  are placed in the second recess  64 . At that time, the upstream end  672  of the upstream fixing plate  67  does not contact the restriction surface  64 A, while the upstream end surface  52  of the upstream pad  5  contacts the restriction surface  64 A. 
     The insertion portions  682 ,  683  of the stay  68  are inserted into the holder protrusions  61 ,  62 , respectively. The stay  68  is thus positioned to the holder  6 . The stay may be attached to the holder before the pads are attached to the holder. 
     As illustrated in  FIG. 5B , a measurement is made to obtain a dimension L between the upper front edge  40  and a reference surface  61 A of the holder protrusion  61 . The reference surface  61 A is, for example, an end surface of the holder protrusion  61  in the third direction and a flat surface orthogonal to the third direction. Thereafter, the holder body  60  is inserted into the interior space of the belt  3 . 
     As illustrated in  FIG. 6 , the belt  3  is sandwiched between the side frame  7 R and the side frame  7 L. At that time, the holder protrusion  61  is inserted into the opening  71  in the side frame  7 R. The holder protrusion  62  is inserted into the opening  71  in the side frame  7 L. 
     The bracket  9 R is placed on the flat surface  72  of the side frame  7 R. The bracket  9 L is placed on the flat surface  72  of the side frame  7 L. At that time, the second support portion  90  in the bracket  9 R receives the holder protrusion  61 . The second support portion  90  in the bracket  9 L receives the holder protrusion  62 . The first contact portion  91  receives the first protrusion  73 . The second contact portion  92  receives the second protrusion  74 . 
     As illustrated in  FIG. 7 , the heat roller  2  has one end attached to the side frame  7 R via the bearing  11  and the other end attached to the side frame  7 L via the bearing  12 . The side frame  7 R and the side frame  7 L are connected to each other with a connecting plate  7   x . The fixing device  1  includes the connecting plate  7   x  connecting the side frames  7 L,  7 R. The brackets  9 R,  9 L are slid in the third direction based on the dimension L and the downstream pad  4  is thus positioned to a predetermined position. 
     The bracket  9 R is secured to the side frame  7 R with the first screws  14 A. The bracket  9 L is secured to the side frame  7 L with the second screws  14 B. The fixing device  1  is manufactured in this manner. 
     4. Operational Effects of First Embodiment 
     As illustrated in  FIG. 2 , the contact area A between the stay  68  and the holder  6  is located downstream of the center B of the nip N in the third direction. Thus, the urging forces of the springs  691  efficiently act on the downstream pad  4  more than on the upstream pad  5  located upstream of the downstream pad  4  in the third direction. The contact area A between the stay  68  and the holder  6  is located upstream of the center C of the downstream pad  4  in the third direction. This prevents the holder  6  from rotating such that the upstream pad  5  is separated from the heat roller  2 . 
     Consequently, the pressure can be set greater in the downstream nip N 1  formed by the downstream pad  4  than in the upstream nip N 2  formed by the upstream pad  5 . The holder  6  is resistant to rotation, unlike a structure where the contact area A is located at a position overlapping the center C in the third direction. This structure thus prevents the pressure distribution in the nip N in the third direction from becoming unstable. 
     The upstream pad  5  is spaced from the downstream pad  4 . This enables widening of the nip N where the heat roller  2  and the belt  3  contact each other. The contact area A between the stay  68  and the holder  6  is located closer to the downstream pad  4  than to the upstream pad  5 . In the wide nip N, the urging forces from the springs  691  can be exerted on the downstream pad  4 . Consequently, a required pressure distribution can be formed in the wide nip N. 
     The stay  68  is disposed at a position different from the downstream pad  4  in the third direction. The stay  68  is disposed downstream of the center B of the nip N and upstream of the downstream pad  4  in the third direction. This reliably prevents the holder  6  from rotating such that the upstream pad  5  is separated from the heat roller  2 . Consequently, the pressure distribution in the nip N in the third direction can be prevented from becoming unstable. 
     The stay  68  is disposed at a position not overlapping the downstream pad  4  in the third direction. The stay  68  is thus insusceptible to heat from the heater  21 , unlike, for example, a stay disposed at a position overlapping the downstream pad  4  in the third direction. This reduces the stay  68  from deforming with heat and thus improves the stability of the pressure distribution in the nip N in the third direction. 
     In the downstream pad  4 , the upper front edge  40  brings the belt  3  into contact with the heat roller  2 , while the upper rear edge  41  does not bring the belt  3  into contact with the heat roller  2 . In the image fixing operation, the downstream pad  4  can impart an appropriate pressure to a sheet. The pressure distribution in the nip N in the third direction can be appropriately adjusted. 
     The contact area A between the stay  68  and the holder  6  is located upstream of the upper front edge  40  in the third direction. The contact area A is located downstream of the center B of the nip N and upstream of the upper front edge  40  in the third direction. This reliably prevents the holder  6  from rotating such that the upstream pad  5  is separated from the heat roller  2 . 
     The contact area A is located upstream of the upper front edge  40  in the third direction. This reduces the heat transfer from the heater  21 , via the downstream pad  4  and the holder  6 , to the stay  68  and thus reduces the stay  68  from deforming with heat. This improves the stability of the pressure distribution in the nip N in the third direction. 
     In the upstream pad  5 , the upper rear edge  55  brings the belt  3  into contact with the heat roller  2 , while the upper front edge  54  does not bring the belt  3  into contact with the heat roller  2 . The pressure distribution in the nip N in the third direction can be appropriately adjusted. 
     As illustrated in  FIG. 4 , the side frame  7 R that supports the heat roller  2  includes the first protrusion  73  and the bracket  9 R includes the first contact portion  91 . The first contact portion  91  contacts the first protrusion  73  in the second direction. The bracket  9 R is movable in the third direction with the first protrusion  73  contacting the first contact portion  91 . 
     When the downstream pad  4  attached to the holder  6  deviates from its expected position, the bracket  9 R can be moved in the third direction to adjust the position of the downstream pad  4  relative to the heat roller  2  in the third direction. This improves the positioning accuracy of the downstream pad  4  relative to the heat roller  2 . 
     As illustrated in  FIG. 3 , the first support portion  70  in the side frame  7 R positions the heat roller  2  relative to the side frame  7 R in a radial direction of the heat roller  2 . The bracket  9 R can be moved in the third direction to adjust the position of the downstream pad  4  relative to the heat roller  2  in the third direction. 
     The first support portion  70  in the side frame  7 R supports the bearing  11  and positions the heat roller  2  in the radial direction. The side frame  7 R can thus receive a load applied, in the second direction, to the heat roller  2  via the bearing  11 . This stabilizes the position of the heat roller  2  relative to the side frame  7 R and the position of the downstream pad  4  relative to the heat roller  2  in the second direction. 
     As illustrated in  FIG. 4 , the bracket  9 R includes the second support portion  90 . The second support portion  90  supports the holder  6  movably in the second direction. The pressure of the downstream pad  4  to be applied to the heat roller  2  is adjusted by moving the holder  6 . 
     The contact surface  90 A contacts the holder protrusion  61  in the third direction. The second support portion  90  can thus receive a load applied, in the third direction, to the holder  6 . This stabilizes the position of the downstream pad  4  relative to the heat roller  2  in the third direction. 
     After the position of the downstream pad  4  is adjusted relative to the heat roller  2  in the third direction, the first screws  14 A are tightened so that the bracket  9 R is secured to the side frame  7 R. 
     The first protrusion  73  contacts the first contact portion  91  upstream relative to the holder  6  in the third direction, and the second protrusion  74  contacts the second contact portion  92  downstream relative to the holder  6  in the third direction. This structure allows the bracket  9 R to slide relative to the side frame  7 R in the third direction and thus improves the positioning accuracy of the downstream pad  4  relative to the heat roller  2  in the third direction. 
     The restriction surface  63 A contacts the downstream pad  4  in the third direction. This improves the positioning accuracy of the downstream pad  4  relative to the holder  6  in the third direction. 
     The stay body  681  is located toward the downstream pad  4  relative to a midpoint between the downstream pad  4  and the upstream pad  5  in the third direction. The downstream pad  4  thus receives greater loads from the urging members  69  via the stay  68  than the upstream pad  5 . The bracket  9 R can be moved in the third direction to adjust the position of the downstream pad  4 , which receives relatively great loads, relative to the heat roller  2  in the third direction. 
     5. Variations of First Embodiment 
     Referring to  FIG. 8 , a first variation of the first embodiment will be described. In the following description, elements similar to or identical with those illustrated in the above embodiment are designated by similar numerals, and thus the description thereof can be omitted for the sake of brevity. 
     As illustrated in  FIG. 8 , a fixing device according to the first variation includes a contact member  15 . The contact member  15  is attached to the side frame  7 R. The contact member  15  is disposed on the flat surface  72  of the side frame  7 R. The contact member  15  contacts the bracket  9 R in the third direction. The contact member  15  includes a shaft  151 . The shaft  151  extends in the first direction. The shaft  151  is fixed to the side frame  7 R. The contact member  15  is pivotable about the shaft  151  to be fixedly positioned relative to the bracket  9 R. 
     According to the first variation, the contact member  15  contacts the bracket  9 R in the third direction. This improves the positioning accuracy of the bracket  9 R relative to the side frame  7 R in the third direction. The first variation may achieve the same operational effects as the first embodiment described above. 
     Referring to  FIG. 9 , a second variation of the first embodiment will be described. In the following description, elements similar to or identical with those illustrated in the above embodiment are designated by similar numerals, and thus the description thereof can be omitted for the sake of brevity. 
     A fixing device according to the second variation includes a pair of side frames  8 R,  8 L and a pair of brackets  9 X. As illustrated in  FIG. 9 , a side frame  8 R includes a support portion  80 , an opening  81 , a first contact portion  83 , and a second contact portion  84 . The support portion  80  and the opening  81  are identical in shape and function to the first support portion  70  and the opening  71 , respectively, which are described in the first embodiment. The bracket  9 X includes a second support portion  90 X, a pin  91 X, a pin  92 X, a long hole  93 X, and a long hole  94 X. The second support portion  90 X is identical in shape and function to the second support portion  90  described in the first embodiment. The long hole  93 X and the long hole  94 X are identical in shape and function to the long hole  93  and the long hole  94 , respectively, which are described in the first embodiment. The pins  91 X,  92 X, which are press fitted into the holes in the bracket  9 X, are formed in one piece with the bracket  9 X. The pins  91 X,  92 X are of cylindrical shape extending in the first direction and protrude toward the side frame  8 R. The pin  91 X is located upstream of the second support portion  90 X in the third direction. The pin  92 X is located downstream of the second support portion  90 X in the third direction. 
     The first contact portion  83  is located upstream of the opening  81  in the third direction. The second contact portion  84  is located downstream of the opening  81  in the third direction. The first contact portion  83  is a long hole that is long in the third direction and into which the pin  91 X is inserted. In the second direction, a width of the first contact portion  83  is nearly equal to the outside diameter of the pin  91 X. In the third direction, a width of the first contact portion  83  is greater than the outside diameter of the pin  91 X. The pin  91 X inserted into the first contact portion  83  is thus movable in the third direction. The second contact portion  84  and the pin  92 X may be taken as having similar relationship to the first contact portion  83  and the pin  91 X, and thus will be simply illustrated. 
     The second variation may achieve the same operational effects as the first embodiment described above. 
     6. Second Embodiment 
     Referring to  FIGS. 10 to 15 , a second embodiment of the disclosure will be described. In the following description, elements similar to or identical with those illustrated in the above embodiment are designated by similar numerals, and thus the description thereof can be omitted for the sake of brevity. 
     A fixing device  200  according to the second embodiment includes a heat roller  2  as an example of a roller, a belt  3 , a downstream pad  4 , an upstream pad  205 , a holder  206 , a sliding sheet  207 , a stay  201 , a sub-stay  202 , a pair of urging members  212 , a plurality of connectors  208 , a plurality of first screws  209 , an upstream guide  203 , a plurality of second screws  210 , a downstream guide  204 , and a plurality of third screws  211 . 
     6.1 Upstream Pad  205   
     The upstream pad  205  is identical in structure to the upstream pad  5  described in the first embodiment, except for dimensions in the second direction and the third direction. Hereinafter, the upstream pad  205  will be simply described and illustrated. In the second direction, the upstream pad  205  has a greater dimension than the downstream pad  4  and the upstream pad  5 . In the third direction, the upstream pad  205  has a greater dimension than the downstream pad  4  and the upstream pad  5 . 
     6.2 Holder  206   
     The holder  206  holds the downstream pad  4  and the upstream pad  205 . The holder  206  is identical in structure to the holder body  60  described in the first embodiment, except for a dimension of the second recess  64  in the third direction. Hereinafter, the holder  206  will be simply described and illustrated. In the third direction, the second recess  64  of the holder  206  has a greater dimension than the second recess  64  of the holder body  60 . In the third direction, the second recess  64  has a greater dimension than the first recess  63 . 
     6.3 Sliding Sheet  207   
     The sliding sheet  207  is used to facilitate the smooth sliding of the belt  3  on the downstream pad  4  and the upstream pad  205 . The sliding sheet  207  extends through between the belt  3 , the downstream pad  4 , and the upstream pad  205 . The sliding sheet  207  is pinched in the nip N between an inner peripheral surface of the belt  3  and the downstream pad  4  and between the inner peripheral surface of the belt  3  and the upstream pad  205 . The sliding sheet  207  has a first end and a second end apart from the first end. The first end of the sliding sheet  207  is fixed to the upstream guide  203 . The second end of the sliding sheet  207  is not fixed to any members. The second end of the sliding sheet  207  may be fixed to the downstream guide  204 . 
     6.4 Stay  201   
     The stay  201  supports the holder  206 . The stay  201  is located opposite to the heat roller  2  relative to the holder  206  in the second direction. The stay  201  contacts the holder  206 . The stay  201  may be made of a sheet of metal and is bent by hemming. The stay  201  has a first end surface  201 A and a second end surface  201 B apart from the first end surface  201 A. The first end surface  201 A and the second end surface  201 B extend in the third direction. The first end surface  201 A contacts the holder  206 . 
     As illustrated in  FIG. 11 , a contact area A between the first end surface  201 A of the stay  201  and the holder  206  is located downstream of a center B of the nip N and upstream of a center C of the downstream pad  4  in the third direction. The contact area A is located between the center B of the nip N and the center C of the downstream pad  4  in the third direction. The contact area A is located closer to the downstream pad  4  than to the upstream pad  205  in the third direction. The stay  201  is disposed at a position overlapping the downstream pad  4  in the third direction. When projected in the second direction, the contact area A overlaps the upper front edge  40 . The second end surface  201 B is located upstream of the first end surface  201 A in the third direction. The second end surface  201 B does not contact the holder  206 . The second end surface  201 B is spaced from the holder  206  in the second direction. The second end surface  201 B is located upstream of the first end surface  201 A in the second direction. 
     6.5 Sub-Stay  202   
     The sub-stay  202  is located opposite to the heat roller  2  relative to the holder  206  in the second direction. The sub-stay  202  is located upstream of and spaced from the stay  201  in the third direction. The sub-stay  202  is contactable with the holder  206 . The sub-stay  202  may be made of a sheet of metal and is bent in L-shape. As illustrated in  FIG. 10 , the sub-stay  202  has a first end surface  202 A and a second end surface  202 B apart from the first end surface  202 A. The first end surface  202 A extends in the third direction. The first end surface  202 A is located between the second end surface  201 B of the stay  201  and the holder  206  in the second direction. The second end surface  202 B extends in the second direction, and faces and is spaced from the stay  201  in the third direction. 
     The first end surface  202 A is contactable with the holder  206 . The first end surface  202 A is spaced from the holder  206 , which remain not deformed, in the second direction. The first end surface  202 A is located, in the second direction, between the first end surface  201 A and the second end surface  201 B of the stay  201 . The first end surface  202 A is contactable with the holder  206  when the holder  206  becomes deformed in response to the urging member  212  urging the stay  201  to the holder  206 . A contactable area D of the sub-stay  202  where the first end surface  202 A is contactable with the holder  206  is located upstream of the nip N in the third direction. In other words, the contactable area D of the sub-stay  202  is located, in the third direction, upstream of and spaced from an upstream end of the upstream nip N 2 . When the holder  206  becomes deformed, the sub-stay  202  contacts the holder  206  upstream of the nip N in the third direction. Unlike a structure where the area D is located at a position overlapping the nip N in the third direction, however, the contact between the sub-stay  202  and the holder  206  is less likely to exert an influence on the fluctuations of the pressure distribution in the nip N. The sub-stay  202  can lessen the force with which the holder  206  becomes deformed. 
     6.6 Urging Members  212   
     As illustrated in  FIG. 12 , the two urging members  212  press the stay  201  toward the heat roller  2 . The urging members  212  are spaced from each other in the first direction. Each urging member  212  includes a spring  212 A and a contact portion  212 B. In other words, the fixing device  200  includes the springs  212 A. The springs  212 A urge the downstream pad  4  and the upstream pad  205  toward the heat roller  2  via the stay  201 . The downstream pad  4  and the upstream pad  205  thus press the belt  3  via the sliding sheet  207  toward the heat roller  2 . The springs  212 A are helical compression springs each including a plurality of turns of wire. The contact portions  212 B are located at respective one ends of the urging members  212 . The contact portions  212 B contact respective end portions of the stay  201  in the first direction. Respective other ends of the urging members  212  are supported by the side frames. 
     6.7 Connectors  208  and First Screws  209   
     As illustrated in  FIG. 13 , the sub-stay  202  is connected to the stay  201 . More specifically, the sub-stay  202  is connected to the stay  201  with the connectors  208  and the first screws  209 . The connectors  208  are fixed to the sub-stay  202 . Each connector  208  includes a screw-fixing portion  208 A and a boss  208 B. 
     The screw-fixing portion  208 A is located downstream of the sub-stay  202  in the third direction. The screw-fixing portion  208 A extends in the third direction. The screw-fixing portion  208 A passes through a first hole  201 C and a second hole  201 D, which are in the stay  201 , in the third direction. The screw-fixing portion  208 A has a screw hole  208 C extending in the third direction. The boss  208 B protrudes from the screw-fixing portion  208 A in a direction away from the stay  201 . The boss  208 B is inserted into a first hole  202 C in the sub-stay  202 . The boss  208 B inserted into the first hole  202 C is crimped and deformed. Each connector  208  is thus fixed to the sub-stay  202 . The first screws  209  are used to fix the connectors  208  to the stay  201 . Each first screw  209  is screwed into a screw hole  208 C from an opposite side of the stay  201  to the sub-stay  202 . 
     6.8 Upstream Guide  203  and Second Screws  210   
     As illustrated in  FIGS. 14 and 15 , the upstream guide  203  includes an upstream guide body  203 A and a plurality of screw-fixing portions  203 B. The screw-fixing portions  203 B will be described in detail later. The upstream guide body  203 A is located upstream relative to the upstream pad  205  in the third direction. The upstream guide body  203 A guides rotation of the belt  3  via the sliding sheet  207 . The upstream guide  203  is fixed to the sub-stay  202 . The upstream guide body  203 A has a plurality of screw holes  203 C. The screw holes  203 C communicate with second holes  202 D in the sub-stay  202  in the third direction. The second screws  210  are used to fix the upstream guide  203  to the sub-stay  202 . Each second screw  210  is screwed into a screw hole  203 C from an opposite side of the sub-stay  202  to the upstream guide  203 . 
     6.8 Downstream Guide  204  and Third Screws  211   
     As illustrated in  FIG. 15 , the downstream guide  204  includes a downstream guide body  204 A and a fixing portion  204 B. The downstream guide body  204 A is located downstream relative to the downstream pad  4  in the third direction. The downstream guide body  204 A guides rotation of the belt  3  via the sliding sheet  207 . The fixing portion  204 B extends continuously from the downstream guide body  204 A. The fixing portion  204 B contacts the stay  201 . The fixing portion  204 B has a plurality of holes  204 C. The holes  204 C communicate with third holes  201 E in the stay  201  in the third direction. 
     The downstream guide  204  is connected to the upstream guide  203 . More specifically, the downstream guide  204  is connected to the screw-fixing portions  203 B of the upstream guide  203 . The screw-fixing portions  203 B extend from the upstream guide body  203 A in the third direction. Each screw-fixing portion  203 B passes through a third hole  202 E in the sub-stay  202  and a fourth hole  201 F in the stay  201 , in the third direction. Each screw-fixing portion  203 B has a screw hole  203 C extending in the third direction. The screw hole  203 C communicates with the third hole  201 E and the hole  204 C in the third direction. The third screws  211  are used to fix the downstream guide  204  to the upstream guide  203 . Each third screw  211  is screwed into the screw hole  203 C from an opposite side of the fixing portion  204 B to the screw-fixing portion  203 B via the hole  204 C and the third hole  201 E. 
     The downstream guide  204  may be fixed to the stay  201 . 
     7. Operational Effects of Second Embodiment 
     As illustrated in  FIG. 11 , the contact area A between the stay  201  and the holder  206  is located, in the third direction, downstream of the center B of the nip N and upstream of the center C of the downstream pad  4 . Thus, the pressure can be set greater in the downstream nip N 1  formed by the downstream pad  4  than in the upstream nip N 2  formed by the upstream pad  205 . The pressure distribution in the nip N in the third direction can be prevented from becoming unstable. The second embodiment may achieve the same operational effects as the first embodiment described above. 
     8. First Embodiment, Its Variations, and Second Embodiment 
     The first and second embodiments show but are not limited to that the heat roller  2  as an example of a rotator includes the heater  21  located in the roller body  20 . For example, the fixing device may be an externally-heating device including a heater disposed outside of the rotator for heating the outer peripheral surface of the rotator. Alternatively, the fixing device may use the induction heat (IH) process to heat the rotator with induction. Alternatively, the heater may be disposed within an interior space of the belt. In this case, a favorable relationship between the rotator and the belt may be opposite to the above-described relationship. Specifically, the rotator and the belt surrounding the heater may be disposed such that the outer peripheral surface of the belt contacts a surface of a sheet on which a toner image has been transferred and the rotator contacts an opposite surface of the sheet. The fixing device may be disposed in an image forming apparatus including a plurality of photosensitive drums.