Image forming apparatus

Abstract

The present invention aims to provide an image forming apparatus that reliably positions a heating unit at a reference position when the heating unit is moved from a position away from the fixing unit toward a reference position. The heating unit has a locking portion. The fixing unit has a locking portion. The heating unit or the fixing unit has a locking guide portion. A moving mechanism holds the heating unit in a tilted position when the heating unit is moved away from the fixing unit. The locking guide portion guides the locking portion toward the locking portion and causes the heating unit to swing from the tilted position toward the reference position. The locking portion restricts the movement of the heating unit longitudinally by engaging with the locking portion. A unit force application portion maintains the engagement state between the locking portion and the locking portion.

Description

TECHNICAL FIELD

[0001] The present application relates to an image forming apparatus of an electrophotographic system, which has a heating unit and a fixing unit. BACKGROUND

[0002] An image forming apparatus of an electrophotographic system transfers a toner image from an image carrier to a sheet and fixes the toner image on the sheet by a fixing apparatus.

[0003] The fixing apparatus is sometimes divided into a heating unit having a heater and a fixing unit having a fixing member and a pressure roller. The heater heats the fixing member.

[0004] Further, it is known that the image forming apparatus has a mechanism that moves the heating unit from a heating position to a retreat position in association with an operation of an operation section. When the heating unit is retreated to the retreat position, the fixing unit can be pulled out from a main body.

[0005] However, it is important to arrange the heater at an appropriate position with respect to the fixing member in order to improve heating efficiency of the heater that heats the fixing member. In a case where a heating apparatus of an electromagnetic induction heating type is employed as the heater, the position accuracy of the heater is particularly important.

[0006] Further, in order to be able to pull out the fixing unit from the main body, a moving mechanism that moves the heating unit is required. The moving mechanism has a proximity function and a retreat function.

[0007] The proximity function is a function that positions the heating unit at a reference position that is close to the fixing unit. The retreat function is a function that moves the heating unit to a retreat position that is away from the fixing unit.

[0008] Therefore, the moving mechanism is required to reliably position the heating unit at the reference position when the heating unit is moved from the retreat position to the reference position. SUMMARY

[0009] An object of the present application is to provide an image forming apparatus that reliably positions a heating unit at a reference position when the heating unit is moved from a position away from a fixing unit to the reference position.

[0010] An image forming apparatus of one aspect of the present invention includes a heating unit having a heater arranged in a main body along a first direction; a fixing unit having a rotatable fixing member heated by the heater and a pressure member that exerts a pressure on a sheet body toward the fixing member, arranged in the main body along the first direction next to the heating unit; a moving mechanism that moves the heating unit along a second direction that is an arrangement direction of the heating unit and the fixing unit; and a unit pressure applying portion that exerts a pressure on the heating unit toward the fixing unit when the heating unit is present at a reference position in the second direction, the first direction being a direction along a center line of rotation of the fixing member, the heating unit having an engaged portion, the fixing unit having an engaging portion that engages with the engaged portion when the heating unit is present at the reference position, the heating unit or the fixing unit having an engaging guide portion that guides the engaged portion toward the engaging portion, the heating unit being linked to the moving mechanism in a manner that is able to swing between a reference posture and a tilted posture that tilts toward a lower side of the fixing unit, the moving mechanism holding the heating unit in the tilted posture when moving the heating unit to a position that is farther from the fixing unit than the reference position, the engaging guide portion guiding the engaged portion toward the engaging portion and swinging the heating unit from the tilted posture toward the reference posture when the heating unit is moved toward the reference position, the engaging portion restricting movement of the heating unit in a longitudinal direction that intersects the first direction and the second direction by engaging with the engaged portion, the unit pressure applying portion maintaining the engaged state of the engaging portion and the engaged portion by exerting a pressure on the heating unit.

[0011] According to the present invention, it is possible to provide an image forming apparatus that is able to reliably position a heating unit at a reference position when moving the heating unit from a position that is farther from a fixing unit than the reference position.

[0012] This specification suitably refers to the accompanying drawings by way of summarizing the contents of the concepts described in the following detailed description in a brief manner. The intention of this specification is not to limit the important features and the essential features of the subject matter recited in the claims, and furthermore, it is not to limit the scope of the subject matter recited in the claims. Furthermore, the subject matter recited in the claims is not limited to the embodiments that solve part or all of the disadvantages recited in any part of the present invention. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a configuration view of an image forming apparatus of an embodiment.

[0014] Figure 2 is a configuration view that represents a main part of a fixing apparatus of an image forming apparatus of an embodiment.

[0015] Figure 3 is a perspective view of a main frame of an image forming apparatus of an embodiment.

[0016] Figure 4 is a side view showing a configuration of a heating unit present at a reference position and its surrounding portion in an image forming apparatus of an embodiment.

[0017] Figure 5 is a plan view showing a configuration of a heating unit and its surrounding portion in an image forming apparatus of an embodiment.

[0018] Figure 6 is a side view showing a configuration of a heating unit present at a retreat position and its surrounding portion in an image forming apparatus of an embodiment.

[0019] Figure 7 is a perspective view of a fixing unit and a surrounding portion of a cover member of an image forming apparatus of an embodiment.

[0020] Figure 8 is a view showing a back surface of a fixing unit and a driving mechanism of an image forming apparatus of an embodiment. DETAILED DESCRIPTION

[0021] Hereinafter, an embodiment of the present application will be described with reference to the drawings. In addition, the following embodiment is an example in which the present application is embodied, and does not limit the technical scope of the present application.

[0022] [Configuration of image forming apparatus 10]

[0023] The image forming apparatus 10 of the embodiment performs a print process in an electrophotographic manner. The print process is a process of forming an image on a sheet 900.

[0024] As shown in Figure 1 , the image forming apparatus 10 is provided with a sheet storage portion 2, a sheet conveyance device 3, and a print device 4. The sheet conveyance device 3 and the print device 4 are stored in a main body 1 that is a case.

[0025] The sheet storage portion 2 is capable of storing a plurality of sheets 900. The sheet conveyance device 3 is provided with a sheet supply device 30 and a plurality of sets of conveyance roller pairs 31.

[0026] The sheet supply device 30 feeds the sheets 900 in the sheet storage portion 2 one by one to a conveyance passage 300. The conveyance passage 300 is a passage of the sheets 900.

[0027] The plurality of sets of conveyance roller pairs 31 convey the sheets 900 along the conveyance passage 300. The plurality of sets of conveyance roller pairs 31 include an ejection roller pair 31a (refer to FIG. 2) and a conveyance roller pair 31b (refer to FIG. 2). Figure 1The discharge roller pair 31a discharges the sheet body 900 with the image formed from the conveying channel 300 onto the discharge plate 1a.

[0028] The printing device 4 performs the printing process on the sheet 900 conveyed along the transport channel 300. The image formed on the sheet 900 is a toner image.

[0029] The printing apparatus 4 includes a light scanning unit 40, one or more image forming units 4x, a transfer device 45, and a fixing device 5. The image forming unit 4x includes a photosensitive element 41, a charging device 42, a developing device 43, and a drum cleaning device 44.

[0030] The charging device 42 charges the surface of the photoreceptor 41. The optical scanning unit 40 scans a light beam onto the charged surface of the photoreceptor 41. As a result, the optical scanning unit 40 forms an electrostatic latent image on the surface of the photoreceptor 41.

[0031] The developing apparatus 43 develops the electrostatic latent image into a toner image by supplying toner to the surface of the photoreceptor 41. The transfer apparatus 45 transfers the toner image formed on the surface of the photoreceptor 41 to the film body 900.

[0032] The transfer device 45 transfers the toner image to the sheet body 900 at the transfer position P1 in the transport channel 300.

[0033] In this embodiment, the printing device 4 is a serial color printing device having multiple image forming units 4x. Additionally, the transfer device 45 includes an intermediate transfer belt 450, multiple primary transfer units 451, secondary transfer units 452, and a belt cleaning device 453.

[0034] exist Figure 1 In the example shown, the printing apparatus 4 has four image forming units 4x corresponding to the four colors of toner: yellow, magenta, cyan, and black. The transfer apparatus 45 has four primary transfer units 451 corresponding to the four image forming units 4x.

[0035] The intermediate transfer belt 450 is supported by a plurality of support rollers 454 so that it can rotate. One of the plurality of support rollers 454 is driven to rotate by a belt drive device (not shown). Thus, the intermediate transfer belt 450 rotates.

[0036] Each primary transfer device 451 transfers the toner image formed on the surface of the photoreceptor 41 in each image forming unit 4x to the surface of the intermediate transfer belt 450. Thus, a composite toner image, obtained by combining the four toner images, is formed on the surface of the intermediate transfer belt 450.

[0037] The intermediate transfer belt 450 carries the synthetic toner image to rotate. The secondary transfer device 452 transfers the synthetic toner image formed on the surface of the intermediate transfer belt 450 to the sheet 900 at the transfer position PI.

[0038] The drum cleaning device 44 removes primary waste toner from the surface of the photosensitive drum 41. The primary waste toner is toner remaining on the surface of the photosensitive drum 41 after the primary transfer device 451.

[0039] The belt cleaning device 453 removes secondary waste toner from the surface of the intermediate transfer belt 450. The secondary waste toner is toner remaining on the surface of the intermediate transfer belt 450 after the secondary transfer device 452.

[0040] The fixing device 5 heats and presses the synthetic toner image on the sheet 900 at the fixing position P2 of the conveyance path 300. Thus, the fixing device 5 fixes the synthetic toner image on the sheet 900. The fixing position P2 is a position located downstream of the transfer position PI in the sheet conveyance direction.

[0041] As shown in FIG. 1, the fixing device 5 includes a heater 51, a fixing belt 52, a fixing roller 520, a pressure roller 53, and a sheet separation member 5200. Figure 2

[0042] The fixing belt 52 is a flexible cylindrical member that houses the fixing roller 520. The fixing belt 52 is heated by the heater 51.

[0043] The fixing roller 520 is a cylindrical member that supports the fixing belt 52 on the inside thereof. The fixing roller 520 includes a cylindrical core portion 521 and an elastic portion 522 formed on the outer periphery of the core portion 521.

[0044] The fixing roller 520 is rotatably supported. The fixing belt 52 is rotatable together with the fixing roller 520.

[0045] The fixing belt 52 includes an electrically conductive base material, an elastic layer formed on the outer periphery of the base material, and a release layer formed on the outer periphery of the elastic layer.

[0046] The heater 51 is disposed in opposition to the outer peripheral surface of the fixing belt 52. In the present embodiment, the heater 51 is an electromagnetic induction heating type heating device. The heater 51 mainly heats the base material of the fixing belt 52 using electromagnetic induction.

[0047] The pressure roller 53 is rotatably supported. The pressure roller 53 also includes a cylindrical core portion 531 and an elastic portion 532 formed on the outer periphery of the core portion 531, like the fixing roller 520.

[0048] ​The pressure roller 53 is rotated by a driving device not shown. The fixing belt 52 and the fixing roller 520 rotate in conjunction with the pressure roller 53.

[0049] The fixing belt 52 heats the toner image formed on the sheet 900. The pressure roller 53 presses the toner image toward the sheet 900.

[0050] Further, the fixing belt 52 is an example of a fixing member heated by the heater 51. The pressure roller 53 is an example of a pressure member that applies a force to the fixing belt 52 toward the sheet 900.

[0051] The sheet separation member 5200 peels the sheet 900 from the fixing belt 52 when the sheet 900 is attached to the fixing belt 52.

[0052] The discharge roller pair 31a is capable of discharging the sheet 900 that has passed between the fixing belt 52 and the pressure roller 53 to the discharge tray la (refer to Figure 1 ).

[0053] In the present embodiment, the fixing device 5 is divided into a heating unit 5a and a fixing unit 5b (refer to Figure 4 , 5 ). The heating unit 5a includes the heater 51. The fixing unit 5b includes the fixing roller 520, the fixing belt 52, and the pressure roller 53. The fixing unit 5b is disposed beside the heating unit 5a.

[0054] Further, the discharge unit 32 is disposed above the fixing unit 5b (refer to Figure 1 ). The discharge unit 32 includes the discharge roller pair 31a and a sheet guide member. The sheet guide member guides the sheet 900 conveyed from the fixing device 5 to the discharge roller pair 31a.

[0055] The discharge unit 32 is fixed to the main body frame lx. The discharge unit 32 is an example of a fixed unit fixed within the main body 1.

[0056] The heating unit 5a is disposed in the main body 1 along the first direction Dl. The fixing unit 5b is also disposed in the main body 1 along the first direction Dl.

[0057] In the present embodiment, the first direction Dl is a depth direction of the image forming apparatus 10. When the fixing unit 5b is mounted to the main body 1, the direction along the center line of rotation of the fixing belt 52 and the pressure roller 53 is the first direction Dl.

[0058] The heating unit 5a and the fixing unit 5b are arranged in the second direction D2. That is, the second direction D2 is an arrangement direction of the heating unit 5a and the fixing unit 5b. The second direction D2 is a direction intersecting the first direction Dl.

[0059] By moving the heating unit 5a to a position away from the fixing unit 5b, the fixing unit 5b can be pulled out of the main body 1.

[0060] The exterior member 100 has an opening portion 101 and a cover member 102 (see Figure 7 ). The opening portion 101 is a portion in which an opening is formed that opens one end of the first direction D1 of the fixing unit 5b.

[0061] The cover member 102 is supported by a support shaft 102x. Thus, the cover member 102 can rotate about the support shaft 102x. The cover member 102 can rotate between a closed position in which the opening portion 101 is closed and an open position in which the opening portion 101 is opened.

[0062] When the fixing unit 5b is pulled out of the main body 1, the fixing unit 5b can pass through the opening portion 101 of the exterior member 100.

[0063] However, it is important to arrange the heater 51 at an appropriate position with respect to the fixing belt 52 in terms of improving the heating efficiency of the heater 51 for heating the fixing belt 52. The position accuracy of the heater 51 is particularly important in the case where an electromagnetic induction heating type heating device is employed as the heater 51.

[0064] In addition, in order to be able to pull the fixing unit 5b out of the main body 1, a moving mechanism 7 (see Figures 4 to 6 ) that moves the heating unit 5a is required. The moving mechanism 7 has a proximity function and a retreat function.

[0065] The proximity function is a function of positioning the heating unit 5a at a reference position that is close to the fixing unit 5b. The retreat function is a function of moving the heating unit 5a to a retreat position that is away from the fixing unit 5b.

[0066] Therefore, in the moving mechanism 7, when the heating unit 5a is moved from the retreat position to the reference position, it is required to be able to reliably position the heating unit 5a at the reference position.

[0067] Hereinafter, the configuration of the heating unit 5a and the fixing unit 5b will be described.

[0068] [Configuration of the heating unit 5a and the fixing unit 5b]

[0069] The heating unit 5a has a heater 51 and a first support body 54 (see Figure 4 , 6 ). The first support body 54 is a member that supports the heater 51.

[0070] The fixing unit 5b includes a fixing belt 52, a fixing roller 520, a pressure roller 53, and a second support body 55 (see Figure 4 ,6 ).

[0071] The second support 55 supports the fixing roller 520 and the pressure roller 53 so that they can rotate. The fixing roller 520 supports the fixing belt 52. That is, the fixing belt 52 is supported by the second support 55 via the fixing roller 520.

[0072] [Mechanism for positioning the heating unit 5a and the fixing unit 5b]

[0073] The image forming apparatus 10 includes a main frame 1x and an external component 100 (see reference). Figure 3 , 7 The main frame 1x forms the skeleton of the main body 1. The external components 100 form the external components of the main body 1.

[0074] The main frame 1x is composed of a combination of multiple metal tubes (see reference). Figure 3 The heating unit 5a and the fixing unit 5b are supported by the main frame 1x.

[0075] External component 100 is mounted on the main frame 1x (refer to) Figure 7 The external component 100 constitutes the external casing of the image forming apparatus 10.

[0076] The multiple metal tubes constituting the main frame 1x have two support sections 11 and two beam sections 12 (see reference). Figure 3 ).

[0077] Two support sections 11 are formed along the longitudinal direction D3 and are spaced apart in the first direction D1 (see reference). Figure 3 The vertical direction D3 is the up-down direction.

[0078] Two support columns 11 are formed extending along the longitudinal direction D3 next to the fixing unit 5b (see reference). Figure 4 , 6 ).

[0079] The two support portions 11 include: a first support portion 11a, disposed on the front side of the image forming apparatus 10; and a second support portion 11b, disposed on the rear side of the image forming apparatus 10 (see reference). Figure 3 ).

[0080] Two beams 12 are formed extending laterally below the heating unit 5a and the fixing unit 5b, and are spaced apart in the first direction D1 (see reference). Figure 3 , 5 The horizontal direction is the width direction of the image forming apparatus 10.

[0081] The two beam sections 12 are respectively connected to the two support sections 11 (see reference). Figure 3 For example, the two beam sections 12 are connected to the two support sections 11 by welding.

[0082] The two beam portions 12 include a first beam portion 12a disposed on the front side of the image forming apparatus 10 and a second beam portion 12b disposed on the back side of the image forming apparatus 10 (see Figure 3 ).

[0083] The fixing unit 5b is disposed between the heating unit 5a and the two pillar portions 11 (see Figure 4 ).

[0084] The first support body 54 of the heating unit 5a is placed on the two beam portions 12 in a state of being supported on the two beam portions 12. Likewise, the second support body 55 of the fixing unit 5b is placed on the two beam portions 12 in a state of being supported on the two beam portions 12.

[0085] That is, neither the heating unit 5a nor the fixing unit 5b is fixed with respect to the main body frame lx by a fixing member such as a screw.

[0086] The heating unit 5a and the fixing unit 5b are carried in a state in which the long side direction is along the first direction Dl with respect to the two beam portions 12 (see Figure 7 、 8 ).

[0087] The image forming apparatus 10 further has a unit urging portion 6 (see Figure 4 、 6 ). The unit urging portion 6 and the moving mechanism 7 are disposed in the main body 1.

[0088] The unit urging portion 6 includes a first spring portion 61 and a second spring portion 62 (see Figure 4 、 6 ). The moving mechanism 7 includes an acting member 70 and a linkage mechanism 71 (see Figure 4 、 5 ). The acting member 70 is disposed on the opposite side of the fixing unit 5b with respect to the heating unit 5a. The acting member 70 is linked to the first support body 54.

[0089] The first support body 54 of the heating unit 5a has a plurality of first engaged portions 542 and a plurality of second engaged portions 544 (see Figure 4 、 5 ). The first support body 54 further has a plurality of unit abutting portions 543 (see Figure 4 ).

[0090] The second support body 55 of the fixing unit 5b has a plurality of first engaged portions 553 corresponding to the plurality of first engaged portions 542 (see Figure 4 ). The second support body 55 further has a plurality of engaged portions 554 corresponding to the plurality of unit abutting portions 543 (see Figure 4 ).

[0091] In the present embodiment, the first support body 54 has a pair of first engaged portions 542 formed at two portions spaced apart in the first direction D1. The first support body 54 also has a pair of unit abutting portions 543 formed at two portions spaced apart in the first direction D1.

[0092] The pair of unit abutting portions 543 are formed at positions spaced apart in the longitudinal direction D3 with respect to the first engaged portions 542.

[0093] The second support body 55 has a pair of first engaged portions 553 formed at two portions corresponding to the pair of first engaged portions 542. The second support body 55 has a pair of abutted portions 554 formed at two portions corresponding to the pair of unit abutting portions 543.

[0094] In the present embodiment, each first engaged portion 542 is concave in the second direction D2 (refer to Figure 4 ). In addition, each first engaged portion 553 is convex so as to be fitted into each first engaged portion 542.

[0095] In addition, each first engaged portion 542 can also be convex. In this case, each first engaged portion 553 is concave in the second direction D2.

[0096] In addition, the discharge unit 32 has a second engaged portion 321 corresponding to the second engaged portion 544 (refer to Figure 4 , 5 ). The discharge unit 32 is an example of a fixed unit fixed to the main body 1.

[0097] The pair of first engaged portions 553 engage with the pair of first engaged portions 542 when the heating unit 5a is present at the reference position. The pair of first engaged portions 553 restrict movement of the heating unit 5a in the longitudinal direction D3 by engaging with the pair of first engaged portions 542. The longitudinal direction D3 is an example of a third direction intersecting the first direction D1 and the second direction D2.

[0098] The second engaged portion 321 of the discharge unit 32 restricts movement of the heating unit 5a in the first direction D1 by engaging with the second engaged portion 544.

[0099] In the present embodiment, the second engaged portion 321 is convex along the second direction D2 (refer to Figure 4 , 5 ). The second engaged portion 544 is a pair of standing portions facing each other in the first direction D1 (refer to Figure 5 ). The second engaged portion 321 is inserted between the pair of standing portions of the second engaged portion 544. Thus, the second engaged portion 321 engages with the second engaged portion 544.

[0100] The unit urging portion 6 is arranged on the opposite side of the fixing unit 5b side with respect to the heating unit 5a in the main body 1 (refer to Figure 4 、 6 ). The unit urging portion 6 elastically urges the first support body 54 toward the second support body 55 by urging the first support body 54.

[0101] In the present embodiment, the first spring portion 61 includes a pair of first pressing springs arranged at intervals in the first direction D1. Similarly, the second spring portion 62 includes a pair of second pressing springs arranged at intervals in the first direction D1. The pair of first pressing springs and the pair of second pressing springs are each an example of an elastic member.

[0102] For example, the pair of first pressing springs and the pair of second pressing springs are each supported by four protruding portions 546 of the first support body 54.

[0103] The acting member 70 sandwiches the unit urging portion 6 between the heating unit 5a (refer to Figure 4 ). The unit urging portion 6 elastically urges the first support body 54 toward the second support body 55 by the elastic force (refer to Figure 4 ).

[0104] In the following description, the urging force of the first spring portion 61 on the first support body 54 is referred to as a first urging force F1 (refer to Figure 4 ). In addition, the urging force of the second spring portion 62 on the first support body 54 is referred to as a second urging force F2.

[0105] The resultant force of the first urging force F1 and the second urging force F2 is greater than the static frictional force of the heating unit 5a and the fixing unit 5b with respect to the two beam portions 12 (refer to Figure 4 ).

[0106] The first support body 54 has a rib 541 that is slidable on the upper surfaces of the two beam portions 12. Similarly, the second support body 55 has a plurality of ribs 551 that are slidable on the upper surfaces of the two beam portions 12. The rib 541 of the first support body 54 and the ribs 551 of the second support body 55 are provided to reduce the static frictional force.

[0107] A pair of unit abutting portions 543 is formed in the heating unit 5a at positions lower than the pair of first engaged portions 542 (refer to Figure 4 、 6 ).

[0108] The first spring portion 61 elastically urges the heating unit 5a toward the fixing unit 5b at a position in the longitudinal direction D3 corresponding to the position of the first engaged portion 542. The first spring portion 61 is an example of a first elastic member.

[0109] The second spring portion 62 elastically urges the heating unit 5a toward the fixing unit 5b at a position in the longitudinal direction D3 corresponding to a position of the unit abutting portion 543. The second spring portion 62 is an example of the second elastic portion.

[0110] The first support body 54 of the heating unit 5a further has a pair of engagement guide portions 5420 (refer to Figure 4 、 6 ) corresponding to the pair of first engaged portions 542. The pair of engagement guide portions 5420 guide the pair of first engaged portions 542 toward the first engagement portion 553.

[0111] In addition, in a case where each of the first engaged portions 542 is convex and each of the first engagement portions 553 is concave, each of the engagement guide portions 5420 is formed in the second support body 55 of the fixing unit 5b.

[0112] The link mechanism 71 moves the acting member 70 in the second direction D2. The heating unit 5a moves in the second direction D2 in linkage with the acting member 70. That is, the moving mechanism 7 moves the heating unit 5a in the second direction D2.

[0113] The link mechanism 71 moves the acting member 70 in the second direction D2 in accordance with an operation on a prescribed operation portion. For example, the cover member 102 functions as the operation portion.

[0114] The link mechanism 71 moves the acting member 70 from one of the first position and the second position to the other in linkage with a movement of the operation portion.

[0115] When the acting member 70 is present in the first position, the heating unit 5a is positioned at the reference position in the second direction D2 by the acting force of the unit urging portion 6. That is, the unit urging portion 6 urges the heating unit 5a toward the fixing unit 5b when the heating unit 5a is present at the reference position. The second position is a position farther from the fixing unit 5b than the first position.

[0116] The link mechanism 71 moves the acting member 70 from the first position to the second position in accordance with a first operation on the operation portion. For example, the first operation is an operation of moving the cover member 102 from the closed position to the open position.

[0117] Further, the link mechanism 71 moves the acting member 70 from the second position to the first position in accordance with a second operation on the operation portion. For example, the second operation is an operation of moving the cover member 102 from the open position to the closed position.

[0118] The first support body 54 of the heating unit 5a has a third engaged portion 545 (refer toFigure 4 ).

[0119] The acting member 70 has a third engaging portion 701 (refer to Figure 4 , 6 ) that can engage with the third engaged portion 545. The third engaging portion 701 engages with the third engaged portion 545 midway through the movement of the acting member 70 from the first position to the second position.

[0120] The heating unit 5a is moved from the reference position to a retreat position by the force received from the acting member 70 through the third engaging portion 701 when the acting member 70 is moved from the first position to the second position. The retreat position is a position further away from the fixing unit 5b than the reference position.

[0121] The fixing unit 5b can be pulled out from the main body 1 in a removal direction D11 when the heating unit 5a is positioned at the retreat position (refer to Figure 5 ). The fixing unit 5b is pulled out from the main body 1 without contacting the heating unit 5a. The removal direction D11 is a direction along the first direction D1.

[0122] The heating unit 5a is connected to the acting member 70 in a state in which it can swing between a reference posture and a tilted posture. Figure 4 The reference posture indicates a state in which the heating unit 5a is in the reference posture. Figure 6 The tilted posture indicates a state in which the heating unit 5a is in the tilted posture.

[0123] The reference posture is a posture of the heating unit 5a when the pair of first engaging portions 553 and the pair of first engaged portions 542 are engaged (refer to Figure 4 ). The tilted posture is a posture in which the fixing unit 5b is tilted downward (refer to Figure 6 ). The tilted posture is a posture in which the fixing unit 5b is tilted downward with respect to the reference posture.

[0124] The pair of first engaged portions 542 abut against the pair of first engaging portions 553 using the force of the first spring portion 61 when the heating unit 5a is present at the reference position. Specifically, the inner surfaces of the concave portions of the pair of first engaged portions 542 each abut against the pair of first engaging portions 553 (refer to Figure 4 ).

[0125] Further, the pair of unit abutment portions 543 abut against the pair of abutment portions 554 using the force of the second spring portion 62 when the heating unit 5a is present at the reference position. In the present embodiment, the pair of unit abutment portions 543 are each a curved surface. The pair of abutment portions 554 are each convex along the first direction D1.

[0126] That is, the unit urging portion 6 holds the heating unit 5a in the reference posture when the heating unit 5a is present at the reference position. In addition, the engagement of the third engagement portion 701 with the third engaged portion 545 is released when the heating unit 5a is present at the reference position.

[0127] The pair of first engaged portions 542 and the pair of unit abutting portions 543 abut against the fixing unit 5b at four portions. Thereby, the heating unit 5a is positioned at the target position in the second direction D2.

[0128] Further, the unit urging portion 6 abuts the second support body 55 against the two pillar portions 11 by urging the first support body 54. That is, the unit urging portion 6 urges the second support body 55 via the first support body 54.

[0129] In addition, the second support body 55 has a plurality of column abutting portions 552 (refer to Figures 4 to 6 ) that protrude toward the two pillar portions 11. The plurality of column abutting portions 552 abut against the side surfaces of the two pillar portions 11.

[0130] When the heating unit 5a moves to a position farther from the fixing unit 5b than the reference position, the rib 541 slides on the upper surfaces of the two beam portions 12 (refer to Figure 6 ). In the following description, the case where the heating unit 5a moves to a position farther from the fixing unit 5b than the reference position will be referred to as sliding movement.

[0131] In addition, the two beam portions 12 are an example of a lower support body that supports the heating unit 5a from below so as to be movable along the second direction D2. In addition, the rib 541 is an example of a unit sliding portion.

[0132] When the heating unit 5a slides, the third engagement portion 701 engages with the third engaged portion 545 (refer to Figure 6 ). The posture of the heating unit 5a when the third engagement portion 701 engages with the third engaged portion 545 is the tilted posture. When the heating unit 5a is in the tilted posture, the rib 541 is in contact with the upper surfaces of the two beam portions 12.

[0133] In the present embodiment, the unit urging portion 6 holds the third engagement portion 701 in engagement with the third engaged portion 545 when the heating unit 5a slides.

[0134] When the heating unit 5a slides, the unit urging portion 6 and the third engagement portion 701 hold the heating unit 5a in the tilted posture. When the heating unit 5a slides, the unit urging portion 6 constitutes a part of the moving mechanism 7.

[0135] That is, when the moving mechanism 7 moves the heating unit 5a to a position farther from the fixing unit 5b than the reference position, the moving mechanism 7 holds the heating unit 5a in the pouring posture.

[0136] When the heating unit 5a is moved from the retreat position toward the reference position by the action of the moving mechanism 7, the engagement guide portion 5420 guides the first engaged portion 542 toward the first engagement portion 553, and further, the second engaged portion 544 engages with the second engagement portion 321.

[0137] When the heating unit 5a is moved toward the fixing unit 5b, the heating unit 5a is held in the pouring posture. Thereby, the positional relationship of the first engaged portion 542 and the first engagement portion 553 when the engagement guide portion 5420 contacts the first engagement portion 553 is stabilized. As a result, the first engaged portion 542 is reliably guided toward the first engagement portion 553 by the engagement guide portion 5420.

[0138] By the engagement of the second engagement portion 321 and the second engaged portion 544, the heating unit 5a is positioned at the target position in the first direction D1.

[0139] In addition, when the heating unit 5a is moved toward the reference position, the engagement guide portion 5420 guides the first engaged portion 542 toward the first engagement portion 553. Further, the engagement guide portion 5420 guides the first engaged portion 542 toward the first engagement portion 553 and swings the heating unit 5a from the pouring posture toward the reference posture. At this time, the heating unit 5a swings with the contact point of the rib 541 and the upper surfaces of the two beam portions 12 as the center. Further, the rib 541 departs upward from the two beam portions 12 (refer to FIG. 6). Figure 4 ).

[0140] In the state where the rib 541 departs from the two beam portions 12, the first engagement portion 553 engages with the first engaged portion 542, and the unit abutting portion 543 abuts against the abutted portion 554.

[0141] The unit urging portion 6 urges the heating unit 5a present at the reference position. Thereby, the unit urging portion 6 maintains the engaged state of the first engagement portion 553 and the first engaged portion 542, and maintains the abutted state of the unit abutting portion 543 and the abutted portion 554. The heating unit 5a is held in the reference posture by the action of the unit urging portion 6.

[0142] By the engagement of the pair of first engagement portions 553 and the pair of first engaged portions 542, the heating unit 5a is positioned at the target position in the longitudinal direction D3.

[0143] In the present embodiment, the first urging force F1 is stronger than the second urging force F2. That is, the first spring portion 61 urges the heating unit 5a with a stronger force than the second spring portion 62.

[0144] The first force Fl of the first spring portion 61 functions as a force that lifts the heating unit 5a from the position of the pouring posture to the position of the reference posture. On the other hand, the second force F2 of the second spring portion 62 mainly functions as a force that maintains the abutment state of the unit abutment portion 543 and the abutted portion 554.

[0145] The heating unit 5a and the fixing unit 5b are positioned at the target position in the second direction D2 by being sandwiched between the unit urging portion 6 and the two leg portions 11.

[0146] With the image forming apparatus 10, when the moving mechanism 7 moves the heating unit 5a from the position away from the fixing unit 5b to the reference position, the heating unit 5a can be reliably positioned at the reference position.

[0147] As shown in Figure 8 , the image forming apparatus 10 is provided with a driving mechanism 9 having a driving gear 90. The driving mechanism 9 is provided with a motor, not shown. The driving mechanism 9 transmits a rotational force to the fixing unit 5b through the driving gear 90.

[0148] The fixing unit 5b is provided with a driven gear 530 that engages with the driving gear 90. The driven gear 530 transmits the rotational force received from the driving gear 90 to the fixing roller 520. Thereby, the fixing belt 52 rotates. That is, the driven gear 530 transmits the rotational force to the fixing belt 52 via the fixing roller 520.

[0149] The pressure roller 53 rotates in conjunction with the rotating fixing belt 52. In addition, the driven gear 530 is also a gear that transmits the rotational force to the pressure roller 53 via the fixing roller 520 and the fixing belt 52.

[0150] The direction of the pressure F3 received by the teeth of the driven gear 530 from the teeth of the driving gear 90 is obliquely downward of the two leg portions 11 side (refer to Figure 8 ). Therefore, the pressure F3 received by the teeth of the driven gear 530 from the teeth of the driving gear 90 functions as a force that applies to the fixing unit 5b toward the two leg portions 11 and the two beam portions 12.

[0151] The fixing unit 5b is more firmly positioned in the second direction D2 and the longitudinal direction D3 by the pressure F3 received from the driving gear 90.

[0152] In addition, the image forming apparatus 10 is further provided with a cover urging mechanism 8 installed to the inner side surface of the cover member 102 (refer to Figure 5 ). In addition, the second support body 55 of the fixing unit 5b has a beam abutment portion 555 that protrudes downward from the lower surface (refer to Figure 4 , 7 ).

[0153] The lid force applying mechanism 8 includes a third spring 80, a spring case 81, and a lid body 82 (see FIG. 6). Figure 5 ).

[0154] The spring case 81 houses the third spring 80. The lid body 82 is movably attached to the spring case 81. The third spring 80 is an example of the elastic fixing unit force applying member.

[0155] The third spring 80 is sandwiched between the lid member 102 and the second support body 55 of the fixing unit 5b when the lid member 102 is in the closed position. In the present embodiment, the third spring 80 and the lid body 82 are sandwiched between the lid member 102 and the second support body 55.

[0156] The third spring 80 exerts an elastic force on the second support body 55 in the attachment direction D12 by being sandwiched between the lid member 102 and the second support body 55 (see FIG. 6). Figure 5 ). The attachment direction D12 is a direction opposite to the detachment direction D11.

[0157] Further, the beam abutting portion 555 abuts against one side surface of the two beam portions 12 by the force received by the second support body 55 from the third spring 80 when the lid member 102 is in the closed position. In the present embodiment, the beam abutting portion 555 abuts against the side surface of the second beam portion 12b.

[0158] The fixing unit 5b is positioned in the first direction D1 by the action of the third spring 80 and the beam abutting portion 555.

[0159] Further, the lid force applying mechanism 8 can be attached to the second support body 55 of the fixing unit 5b.

[0160] The scope of the present application is not limited to the above, but is defined by the recitations of the claims, so it can be considered that the embodiments described in the present specification are only illustrative, and not limiting. Therefore, all modifications, and contents equivalent to the scope, limits of the claims are included in the scope of the claims.

Claims

1. An image forming apparatus characterized by comprising: a heating unit having a heater, disposed in a main body along a first direction; a fixing unit having a rotatable fixing member heated by the heater and a pressure member applying a force to a sheet toward the fixing member, disposed in the main body along the first direction next to the heating unit; a moving mechanism moving the heating unit along a second direction which is an arrangement direction of the heating unit and the fixing unit; and a unit force applying portion applying a force to the heating unit toward the fixing unit when the heating unit is present at a reference position in the second direction, the first direction is a direction along a center line of rotation of the fixing member, the heating unit has an engaged portion, the fixing unit has an engaging portion engaging with the engaged portion when the heating unit is present at the reference position, the heating unit or the fixing unit has an engaging guide portion guiding the engaged portion to the engaging portion, the heating unit is linked to the moving mechanism in a manner that can swing between a reference posture and a tilted posture which is tilted toward the fixing unit in a lower direction, the moving mechanism holds the heating unit in the tilted posture when moving the heating unit to a position farther from the fixing unit than the reference position, the engaging guide portion guides the engaged portion to the engaging portion and swings the heating unit from the tilted posture to the reference posture when the heating unit is moved toward the reference position, the engaging portion restricts movement of the heating unit in a longitudinal direction intersecting the first direction and the second direction by engaging with the engaged portion, the unit force applying portion maintains the engaging state of the engaging portion and the engaged portion by applying a force to the heating unit.

2. The image forming apparatus according to claim 1, characterized by further comprising a lower support body supporting the heating unit from below in a manner that the heating unit can move along the second direction, the heating unit has a unit sliding portion which slides on an upper surface of the lower support body when the heating unit is moved to a position farther from the fixing unit than the reference position, the heating unit swings with a contact point of the unit sliding portion and the upper surface of the lower support body as a center and further the unit sliding portion moves upward from the lower support body when the engaging guide portion guides the engaged portion to the engaging portion.

3. The image forming apparatus according to claim 1 or 2, characterized in that the heating unit has a unit abutting portion formed at a position spaced apart from the engaged portion in the longitudinal direction, the unit abutting portion abuts against the fixing unit by a force of the unit force applying portion when the heating unit is present at the reference position.

4. The image forming apparatus according to claim 3, characterized in that ​ ​ The unit abutting portion is formed at a position of the heating unit lower than the engaged portion, The unit urging portion includes: a first elastic portion that elastically urges the heating unit toward the fixing unit at a position in the longitudinal direction corresponding to the position of the engaged portion; and a second elastic portion that elastically urges the heating unit toward the fixing unit at a position in the longitudinal direction corresponding to the position of the unit abutting portion, The first elastic portion urges the heating unit with a force stronger than the second elastic portion.

5. The image forming apparatus according to claim 1 or 2, wherein The heater is a heating device of an electromagnetic induction heating type.

Images