阅读说明：本技术 图像形成装置 (Image forming apparatus with a toner supply device ) 是由 佐藤健大 于 2020-11-27 设计创作，主要内容包括：本发明提供一种图像形成装置。定影单元使承载有调色剂像的片材通过使旋转定影部件和旋转加压部件相互压接而形成的夹持部,从而使调色剂像热定影在该片材上。图像形成装置包括：图像形成装置主体,具有插拔自如地收纳定影单元的定影单元收纳部；以及加热部,设置于图像形成装置主体,从径向外侧对安装于定影单元收纳部的定影单元的旋转定影部件进行加热。定影单元相对于定影单元收纳部的插拔方向与旋转加压部件的轴向一致。(The invention provides an image forming apparatus. The fixing unit thermally fixes the toner image to the sheet by passing the sheet bearing the toner image through a nip formed by pressing a rotary fixing member and a rotary pressing member against each other. The image forming apparatus includes: an image forming apparatus main body having a fixing unit housing section for housing a fixing unit therein in a freely removable manner; and a heating section provided in the image forming apparatus main body and heating a rotary fixing member of a fixing unit attached to the fixing unit housing section from a radially outer side. The fixing unit is inserted into and removed from the fixing unit housing section in the same direction as the axial direction of the rotary pressing member.)

1. An image forming apparatus, comprising:

a fixing unit that thermally fixes a toner image on a sheet bearing the toner image by passing the sheet through a nip formed by pressing a rotary fixing member and a rotary pressing member against each other;

an image forming apparatus main body having a fixing unit housing section configured to removably house the fixing unit; and

a heating section provided in the image forming apparatus main body and configured to heat a rotary fixing member of the fixing unit attached to the fixing unit housing section from a side opposite to the nip section,

the fixing unit is inserted into and removed from the fixing unit housing section in a direction corresponding to an axial direction of the rotary pressing member.

2. The image forming apparatus according to claim 1,

the image forming apparatus includes:

a driving unit configured to move the heating unit between a preset heating position at which a rotary fixing member of the fixing unit attached to the fixing unit housing unit can be heated and a retracted position at which the heating unit is moved outward in a radial direction of the rotary fixing member from the heating position and is retracted outward in an insertion/extraction path of the fixing unit; and

an operation unit which can be operated by a user,

the driving unit is configured to be capable of selectively switching the position of the heating unit between the heating position and the retracted position in conjunction with an operation of the operation unit.

3. The image forming apparatus according to claim 2,

an insertion/extraction opening for inserting and extracting the fixing unit is formed at one end of the fixing unit housing section in an insertion/extraction direction of the fixing unit,

the image forming apparatus further includes an opening/closing door openably/closably closing the insertion/extraction opening,

the operating part is composed of the opening and closing door,

the driving unit is configured to position the heating unit at the heating position in a state where the openable and closable door is fully closed as the operating unit, and to position the heating unit at the retracted position in a state where the openable and closable door is positioned at a predetermined open position where the fixing unit can be inserted and removed through the insertion and removal opening.

4. The image forming apparatus according to claim 1,

the image forming apparatus further includes:

a drum unit including a photosensitive drum for bearing a toner image; and

a developing unit including a developing roller for forming a toner image on the photosensitive drum,

the image forming apparatus main body includes: a drum unit housing unit that houses the drum unit so as to be freely inserted and removed in the same direction as the insertion and removal direction of the fixing unit; and a developing unit housing section configured to house the developing unit so as to be freely inserted and removed in the same direction as the insertion and removal direction of the fixing unit,

the fixing unit receiving portion includes a fixing unit receiving portion, a drum unit receiving portion, and a developing unit receiving portion, and the developing unit receiving portion includes a developing unit receiving portion, a fixing unit receiving portion, and a developing unit receiving portion.

5. The image forming apparatus according to any one of claims 1 to 4,

the heating portion is an IH heating portion having: a holder having a recess that receives a side of an outer peripheral surface of the rotary fixing member opposite to the nip portion side; a plurality of IH coils supported by the support; and an arch core covering the IH coil.

Technical Field

The present invention relates to an image forming apparatus.

Background

Generally, an electrophotographic image forming apparatus includes a fixing unit that fixes a toner image to a sheet by a fixing roller and a pressure roller that rotate in a state of being pressed against each other.

In the fixing unit, when a sheet passes through a nip formed between a fixing roller and a pressure roller, a toner image on the sheet is heated and pressed to be fixed on the sheet.

The image forming apparatus main body is provided with a heating section that heats a fixing roller of a fixing unit. An IH heating unit, which is an example of the heating unit, includes a holder and a plurality of IH coils supported by the holder. The holder has a cylindrical recess into which a surface portion of the fixing roller on the side opposite to the nip portion enters. The IH heating section heats the circumferential surface of the fixing roller from the radially outer side via the concave portion.

The fixing unit is configured separately from the IH heating section and is removably attached to a fixing unit housing section in the image forming apparatus main body. The insertion and extraction direction of the fixing unit is set to a direction facing the inner surface of the recess of the holder (a direction orthogonal to the axial direction of the fixing roller).

In the conventional image forming apparatus, since the fixing unit is inserted and removed in a direction facing the inner surface of the recess of the holder of the IH heating unit (heating unit), only other devices (for example, a drive gear or the like) can be disposed on the heating unit side, and the degree of freedom of the disposition of the devices is significantly limited.

Disclosure of Invention

The present invention has been made in view of the above, and an object thereof is to improve the degree of freedom in arrangement of other devices around the fixing unit.

An image forming apparatus according to the present invention includes: a fixing unit that thermally fixes a toner image on a sheet bearing the toner image by passing the sheet through a nip formed by pressing a rotary fixing member and a rotary pressing member against each other; an image forming apparatus main body having a fixing unit housing section configured to removably house the fixing unit; and a heating section provided in the image forming apparatus main body and configured to heat a rotary fixing member of the fixing unit attached to the fixing unit housing section from a side opposite to the nip section side, wherein a direction of insertion and removal of the fixing unit into and from the fixing unit housing section coincides with an axial direction of the rotary pressing member.

According to the present invention, the degree of freedom in the arrangement of other devices around the fixing unit can be increased.

Drawings

Fig. 1 is a schematic diagram illustrating an image forming apparatus according to an embodiment.

Fig. 2 is a perspective view showing a right end portion of the main body frame viewed from a front oblique right side, and shows a state in which the fixing unit is attached to the fixing unit housing portion and the second maintenance door is fully closed.

Fig. 3 is a perspective view showing a right end portion of the main body frame viewed obliquely from the front and right, and shows a state in the middle of insertion and removal of the fixing unit.

Fig. 4 corresponds to fig. 2, showing a state in which the fixing unit is removed from the fixing unit housing section.

Fig. 5 is a front view showing the discharge unit as viewed from the front side.

Fig. 6 is a sectional view taken along line VI-VI of fig. 2.

Fig. 7 is a sectional view taken along line VII-VII of fig. 2.

Fig. 8 is a schematic side view of the fixing unit as viewed from the opening portion side.

Fig. 9 is a plan view showing a state in which the fixing unit is attached to the fixing unit housing section and the second maintenance door is fully closed.

Fig. 10 corresponds to fig. 9, which shows a state where the second maintenance door is fully opened.

Fig. 11 is a cross-sectional view taken along line XI-XI of fig. 10.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments.

Detailed description of the preferred embodiments

Fig. 1 is a schematic configuration diagram showing an image forming apparatus 1 according to an embodiment. In the following description, front and rear means front and rear sides of the image forming apparatus 1 (front and rear sides in a direction perpendicular to the paper surface of fig. 1), and left and right means left and right sides when the image forming apparatus 1 is viewed from the front side.

[ Overall Structure of image Forming apparatus 1 ]

The image forming apparatus 1 is an in-body paper-discharge type copier, and includes an image forming apparatus main body 2 and an image reading device 3 provided above the image forming apparatus main body 2. The image reading apparatus 3 optically reads a document image and generates image data thereof.

An image forming unit 4 is provided in the image forming apparatus main body 2, and the image forming unit 4 forms an image on a sheet P (an example of a sheet) by transferring based on image data of a document read by the image reading device 3. A transfer unit 6 is disposed above the image forming unit 4. The transfer unit 6 includes an endless intermediate transfer belt 6a extending in the left-right direction, 4 primary transfer rollers 6b arranged inside the intermediate transfer belt 6a in the left-right direction, a drive roller 6c that rotationally drives the intermediate transfer belt, and the like.

An exposure device 5 for irradiating laser light is disposed below the image forming unit 4. A paper feed portion 7 for storing the paper P is disposed below the exposure device 5. A fixing unit 8 for performing a fixing process on the image transferred and formed on the paper P is disposed above and to the right of the transfer unit 6. An internal paper discharge space S is provided between the image forming apparatus main body 2 and the image reading apparatus 3, and the paper P subjected to the fixing process by the fixing unit 8 is discharged into the internal paper discharge space S.

A paper discharge tray part 9 for receiving the paper P discharged to the internal paper discharge space S is formed on the upper surface of the image forming apparatus main body 2. A sheet conveyance path T extending from the sheet feeding unit 7 toward the sheet discharge tray unit 9 is provided in the image forming apparatus main body 2. A secondary transfer roller 10 facing the driving roller 6c is provided below the fixing unit 8 in the paper conveyance path T via the intermediate transfer belt 6 a. A pair of discharge rollers 11 for discharging the sheet P substantially horizontally toward the discharge tray portion 9 is provided above the fixing unit 8 in the sheet conveyance path T.

A rectangular opening 2a is formed in the right side surface of the image forming apparatus main body 2 adjacent to the paper conveyance path T. The opening 2a can be opened and closed by an opening and closing cover 2 b. The opening/closing cover 2b is supported rotatably with respect to a support shaft 2f extending along the lower edge of the opening 2 a. The opening/closing cover 2b is opened by being rotated rightward about the support shaft 2f as a fulcrum from the closed state. By opening the opening/closing cover 2b, the sheet jammed in the sheet transport path T can be removed.

The image forming unit 4 includes a drum unit 20 and a developing unit 30 provided for each of yellow, magenta, cyan, and black colors. The drum unit 20 has a rotatable photosensitive drum 21. An electrostatic latent image is formed by irradiating the surface of the photosensitive drum 21 with laser light based on predetermined image data from the exposure device 5.

The developing unit 30 includes a developing container 31 and a developing roller 32. Each developing container 31 receives toner as a developer supplied from a corresponding toner container (not shown) of each color. The developing roller 32 is exposed from the right side wall of the upper portion of the developing container 31 and is rotatably supported. A potential difference is generated between the developing roller 32 and the surface of the photosensitive drum 21, and the toner is moved from the developing roller 32 to the surface of the photosensitive drum 21. The electrostatic latent image on the surface of the photosensitive drum 21 is visualized by the toner moving from the developing roller 32.

The toner images of the respective colors of the photosensitive drums 21 visualized by the developing units 30 are sequentially transferred and superimposed on the intermediate transfer belt 6a by being biased by the primary transfer rollers 6b disposed above the photosensitive drums 21. The superimposed toner image is transferred to the sheet P fed from the sheet feeding portion 7 when the sheet P passes between the intermediate transfer belt 6a and the secondary transfer roller 10. The sheet P with the toner image transferred thereon is sent to the fixing unit 8.

The fixing unit 8 includes a fixing roller 81 and a pressure roller 82 that face each other in the left-right direction with the paper conveyance path T therebetween. The fixing unit 8 nips and conveys the paper P on which the toner image is formed by the fixing roller 81 and the pressure roller 82. The toner image on the paper P is heated and pressed when passing between the fixing roller 81 and the pressing roller 82, and is thermally fixed to the paper P. The paper P on which the toner image is thermally fixed is discharged to the paper discharge tray portion 9 by the paper discharge roller pair 11 disposed above the fixing unit 8.

[ storage structure of each unit in image forming apparatus main body 2 ]

Next, the structure of housing the drum unit 20, the developing unit 30, and the fixing unit 8 in the image forming apparatus main body 2 will be described.

The image forming apparatus main body 2 includes a main body frame 12 (see fig. 2 and the like) in which a plurality of metal pillars and beams are combined, and an exterior cover (not shown) that covers each side surface of the main body frame 12.

The front exterior cover includes a first maintenance door 13 (see fig. 1) and a second maintenance door 14 (corresponding to an opening/closing door). The first maintenance door 13 extends in a rectangular shape in the left-right direction, and covers the entire front side of the image forming unit 4. The first maintenance door 13 is a split door divided into left and right sides with a center position in the left-right direction as a boundary. The second maintenance door 14 is a square door covering the entire front side of the fixing unit 8. The second maintenance door 14 is a single-opening door that rotates with its left end portion as a fulcrum.

At a portion of the image forming apparatus main body 2 facing the inner side surface of the first maintenance door 13, 4 sets of the drum unit housing portions 2c housing the drum units 20 and the developing unit housing portions 2d housing the developing units 30 are provided in pairs so as to be adjacent to each other in the left-right direction of the image forming apparatus main body 2.

The drum unit housing portion 2c is formed of a hollow space portion extending in the front-rear direction, and an insertion/removal opening for inserting/removing the drum unit 20 is provided at a front end portion thereof. The drum unit 20 is accommodated in the drum unit accommodating portion 2c through the insertion/removal opening so as to be insertable/removable in the front-rear direction.

The developing unit housing portion 2d is formed of a hollow space portion extending in the front-rear direction, and an insertion/removal opening for inserting/removing the developing unit 30 is provided at a front end portion thereof. The developing unit 30 is accommodated in the developing unit accommodating portion 2d through the insertion/removal opening so as to be insertable/removable in the front-rear direction.

A fixing unit housing section 2e for housing the fixing unit 8 is provided in a portion of the image forming apparatus main body 2 facing the inner surface of the second maintenance door 14. The fixing unit housing portion 2e is formed of a hollow space portion extending in the front-rear direction, and an insertion/removal opening for inserting/removing the fixing unit 8 is provided at a front end portion (one side end portion) thereof. A guide member (not shown) for guiding the fixing unit 8 in the front-rear direction is provided in the fixing unit housing 2 e. In the mounting-completed state of the fixing unit 8, the fixing unit 8 is positioned by the guide member so as not to be movable in the left-right direction.

[ detailed Structure of fixing Unit housing section 2e ]

The fixing unit housing section 2e will be described in detail with reference to fig. 2 to 4. Fig. 2 shows a state in which the fixing unit 8 is attached to the fixing unit housing portion 2e and the second maintenance door 14 is fully closed, and fig. 3 shows a state in which the fixing unit 8 is inserted and removed in the middle. Fig. 4 corresponds to fig. 2, showing a state where the fixing unit 8 is removed from the fixing unit housing section 2 e.

The fixing unit housing portion 2e is provided in a lower portion of the inner space K of the protruding frame portion 120 provided in the main body frame 12. The protruding frame portion 120 is provided over the entire front-rear direction of the main body frame 12 adjacent to the right side of the internal sheet discharge space S. The protruding frame portion 120 is configured in a rectangular parallelepiped shape by combining frame members.

The discharge unit 40 including the discharge roller pair 11 is housed in the inner space K of the protruding frame portion 120, and the fixing unit housing portion 2e is configured by a lower space below the discharge roller pair 11 in the inner space K. The insertion/removal opening of the fixing unit 8 is formed between the pair of right and left posts 121 at the front end of the protruding frame portion 120.

[ Structure of the discharge unit 40 ]

Fig. 5 is a schematic configuration diagram of the discharge unit 40. The discharge unit 40 has a pair of discharge rollers 11 and a support frame 41 that supports the pair of discharge rollers 11. The support frame 41 includes a pair of opposing plates 41a that support both end portions of the discharge roller pair 11 in the axial direction, a vertical plate 41b that connects left end portions of the pair of opposing plates 41a and extends in the vertical direction, and a horizontally projecting plate 41c that horizontally projects rightward from a lower end portion of the vertical plate 41 b.

An IH heating unit 50 that heats the fixing roller 81 is supported on the upper surface of the horizontal projecting plate 41c so as to be movable in the left-right direction. The vertical plate 41b is formed with an opening 41d through which the IH heating unit 50 can pass.

The IH heating unit 50 is driven between a heating position and a retracted position by a driving mechanism (driving unit) 60 described later. The heating position is a position at which the surface of the fixing roller 81 can be heated with a prescribed heating performance by the IH heating unit 50. The retracted position is a position at which the IH heating unit 50 is moved leftward from the heating position and retracted to the outside of the movement path of the fixing unit 8.

The fixing unit 8 and the IH heating unit 50 are described in detail with reference to fig. 6. Fig. 6 is a cross-sectional view of the VIVI line of fig. 2, showing a state in which the IH heating unit 50 is located at a heating position.

As described above, the fixing unit 8 has the fixing roller 81, the pressure roller 82, and the fixing housing 83.

The fixing roller 81 and the pressure roller 82 are formed in a substantially cylindrical shape that is long in the front-rear direction. The fixing roller 81 includes an elastic layer 81b laminated on the outer peripheral surface of a metal core rod 81a, and a fixing belt 81c covering the outer peripheral surface of the elastic layer 81 b. The pressure roller 82 includes an elastic layer 82b laminated on the outer peripheral surface of the core rod 82a and a release layer 82c covering the outer peripheral surface of the elastic layer 82 b.

The fixing housing 83 is formed in a substantially rectangular parallelepiped shape long in the front-rear direction. A recessed grip portion 83a (see fig. 3 and the like) is formed on the front surface of the fixing housing 83. The left end of the lower surface of the fixing housing 83 is supported by the right end of a horizontal projection plate 41c (see fig. 5) of the discharge unit 40. The front end and the rear end of the fixing housing 83 are supported by a beam 122 protruding from the front side plate of the main body frame 12 and a beam 123 (see fig. 2) protruding from the rear side plate, respectively.

A paper receiving port 83c for receiving the paper P conveyed from the upstream side of the paper conveying path T is formed in the lower surface of the fixing housing 83. A paper ejection port 83d for ejecting the paper P that has passed through the fixing roller 81 and the pressure roller 82 is formed in the upper surface of the fixing housing 83. A rectangular opening 83b extending in the left-right direction is formed in the left side wall of the fixing housing 83, and the left side half of the fixing roller 81 is exposed to the outside of the fixing housing 83 through the opening 83 b.

The IH heating unit 50 is provided on the opposite side (left side) of the nip portion N via the fixing roller 81. The IH heating unit 50 includes a semi-cylindrical holder 50a opened to the fixing roller 81 side, a plurality of IH coils 50b supported by the holder 50a, and a dome core 50c formed of a ferromagnetic material such as ferrite and covering the IH coils 50 b. The inner surface of the holder 50a forms a semi-cylindrical recess 50g, and the surface of the fixing roller 81 on the side opposite to the nip portion N enters the recess 50g in a state where the IH heating unit 50 is located at the heating position. The holder 50a and the arch core 50c are both provided so as to face the fixing roller 81 and extend over the entire front-rear direction thereof. The bracket 50a and the arch core 50c are connected at both ends in the front-rear direction to a positioning block 50d (see fig. 4) described later.

In the fixing process, the pressure roller 82 is connected to a motor or the like (not shown) via a gear train or the like, and is rotated around an axis by a driving force of the motor. The fixing roller 81 is rotated around its axis by the pressure roller 82. Each IH coil 50b receives power supply from a power supply (not shown), generates a high-frequency magnetic field, and heats the fixing belt 81 c. The fixing roller 81 heats the toner image on the paper P passing through the nip portion N while rotating. The pressure roller 82 presses the paper P passing through the nip N while rotating. Thereby, the toner image is fixed on the paper P. Alternatively, the fixing roller 81 may be driven to rotate and the pressure roller 82 may be driven to rotate.

[ positioning Structure of IH heating Unit 50 ]

As described above, the IH heating unit 50 is configured to be movable between the heating position and the retracted position. The IH heating unit 50 is positioned at the heating position such that the gap between the inner surface of the recess 50g of the holder 50a and the outer circumferential surface of the fixing roller 81 becomes a predetermined distance.

The structure for positioning the IH heating unit 50 is explained with reference to fig. 4, 7, and 8.

Referring first to fig. 4 and 7, positioning block portions 50d (only the rear block portion is shown in fig. 4) are provided at both ends of the IH heating unit 50 in the front-rear direction. A cylindrical surface continuously connected to the inner surface of the recess 50g of the holder 50a is formed on the right side surface of each positioning block 50 d. An upper engaging groove 50e and a lower engaging groove 50f are formed in the upper and lower sides of each positioning block 50d across the cylindrical surface. The upper engagement groove 50e and the lower engagement groove 50f are formed by semi-cylindrical grooves extending in the front-rear direction.

As shown in fig. 7 and 8, the fixing unit 8 includes an upper engaging pin 85 that engages with the upper engaging groove 50e of each positioning block 50d, and a lower engaging pin 86 that engages with the lower engaging groove 50f of each positioning block 50 d.

The upper engagement pin 85 and the lower engagement pin 86 are attached to the support member 84 that supports the fixing roller 81 and the pressure roller 82. The support member 84 is made of, for example, a metal sheet metal member. The support member 84 includes a pair of vertical support plates 84a that face each other in the front-rear direction and support the fixing roller 81 and the pressure roller 82 at both ends thereof, and a connecting plate 84b that connects lower end portions of the pair of vertical support plates 84 a. The upper engagement pin 85 protrudes inward in the front-rear direction from the upper left corner of each vertical support plate 84 a. The lower engagement pin 86 protrudes inward in the front-rear direction from the lower left corner of each vertical support plate 84 a.

As shown in fig. 7, the IH heating unit 50 is positioned at the heating position by engaging the upper engaging groove 50e and the lower engaging groove 50f of the positioning block 50d with the upper engaging pin 85 and the lower engaging pin 86 of the fixing unit 8, respectively.

When the IH heating unit 50 is at the heating position, a part of the positioning block 50d overlaps a part of the support member 84 of the fixing unit 8 as viewed from the front-rear direction. Therefore, the IH heating unit 50 cannot be inserted and removed in the front-rear direction. Therefore, in the present embodiment, when the user opens the second maintenance door 14 (an example of an operation portion) to perform the insertion and extraction work of the fixing unit 8, the IH heating unit 50 is moved from the heating position to the retracted position by the driving mechanism 60.

[ drive mechanism 60 of IH heating Unit 50 ]

An example of the drive mechanism 60 will be described with reference to fig. 9. Fig. 9 shows a state in which the IH heating unit 50 is driven to the heating position by the driving mechanism 60. In the description of the respective components of the driving mechanism 60, the IH heating unit 50 is described as being located at the heating position unless otherwise specified.

The drive mechanism 60 is constituted by a link mechanism interlocked with the opening and closing operation of the second maintenance door 14. Specifically, the drive mechanism 60 includes a door-side link 62 coupled to the second maintenance door 14, a pair of parallel links 63 coupled to the upper surface of the cooling duct 51 of the IH heating unit 50, and an intermediate link 64 coupling the door-side link 62 and the pair of parallel links 63.

The door side link 62 is a plate-like member bent into a "dogleg" shape in plan view, and extends from the front side to the rear side and then extends obliquely to the left side to the rear side.

The intermediate portion of the door-side link 62 is supported rotatably about a door-side fixed shaft 61 provided diagonally to the left and rearward of the second maintenance door 14. The door-side fixed shaft 61 is provided so as to protrude from a front cross member 122 (see fig. 4) constituting a lower side of the front end portion of the protruding frame portion 120.

The front end portion of the door-side link 62 is coupled to the left end portion of the second maintenance door 14 via a coupling pin 66. The door-side link 62 is coupled to the second maintenance door 14 so as to be rotatable about a coupling pin 66.

The rear end portion of the door-side link 62 is coupled to the front end portion of the intermediate link 64 via a coupling pin 67. The intermediate link 64 is coupled to the door-side link 62 so as to be rotatable about a coupling pin 67.

The intermediate link 64 is formed of a plate-like member that extends straight toward the rear side, then bends in a step-like manner, and extends straight toward the rear side. The pair of parallel links 63 are connected to rear end portions of the intermediate links 64 via connecting pins 68, respectively. The intermediate link 64 is coupled to the pair of parallel links 63 to be rotatable about each coupling pin 68.

The pair of parallel links 63 is formed of a plate-like member extending in the left-right direction. Each parallel link 63 has an oblong hole 63a extending from its right end portion to the vicinity of the central portion. A fixing pin 69 is inserted into each of the elongated holes 63 a. The fixing pin 69 is protrudingly provided on the upper surface of the cooling pipe 51 of the IH heating unit 50. The cooling duct 51 supplies air taken into the image forming apparatus main body 2 by a blower fan not shown between the arch core 50c of the IH heating unit 50 and the holder 50 a. The IH coil 50b is cooled by the supply air. In fig. 9, reference numeral 50f denotes a vent hole formed through the upper wall portion of the arch core 50 c.

[ description of operation of the drive mechanism 60]

Next, the operation of the drive mechanism 60 accompanying the opening and closing operation of the second maintenance door 14 will be described with reference to fig. 9 and 10. Fig. 9 shows a state in which the second maintenance door 14 is closed (hereinafter referred to as a fully closed state), and fig. 10 shows a state in which the second maintenance door 14 is rotated 90 degrees to the front side from the fully closed state with the fixing pin 15 as a fulcrum (hereinafter referred to as a fully opened state).

When the second maintenance door 14 is rotated clockwise (D1 direction) about the fixing pin 15 from the fully closed state (the state of fig. 9) of the second maintenance door 14, the front end portion of the door-side link 62 moves diagonally rearward and rightward along the circular track about the fixing pin 15 together with the connecting pin 66. Accordingly, the door-side link 62 rotates counterclockwise (D2 direction) about the door-side fixed shaft 61, and the intermediate link 64 is pulled forward (D3 direction) by the door-side link 62. As a result, the pair of parallel links 63 connected to the rear end portions of the intermediate links 64 are each pivoted counterclockwise (in the direction D4) about the connecting pin 68 as a fulcrum. When the pair of parallel links 63 rotate, the fixing pin 69 inserted into the long hole 63a is pressed leftward by the inner surface of the long hole 63a while relatively moving in the longitudinal direction of the long hole 63 a. As a result, the IH heating unit 50 moves to the left side together with the fixing pin 69. When the second maintenance door 14 is rotated to the fully opened state, the IH heating unit 50 moves to the retracted position outside the insertion and extraction path of the fixing unit 8 as shown in fig. 10.

When the IH heating unit 50 moves to the retracted position, as shown in fig. 11, the entire positioning block portion 50d of the IH heating unit 50 is retracted to the left side of the support member 84 of the fixing unit 8, and the engagement between the engagement pins 85, 86 and the engagement grooves 50e, 50f is released.

Therefore, by moving the IH heating unit 50 to the retracted position, the fixing unit 8 can be inserted and removed in the front-rear direction without interfering with the IH heating unit 50.

[ Effect ]

As described above, in the present embodiment, the insertion/removal direction (front-rear direction) of the fixing unit 8 into/from the fixing unit housing 2e coincides with the axial direction of the pressure roller 82.

According to this configuration, the degree of freedom in the arrangement of other components can be increased as compared with the case where the insertion/removal direction of the fixing unit 8 is set to the direction (left-right direction) orthogonal to the axial direction of the pressure roller 82. As an example of the other components, a drive gear for driving the pressure roller 82 may be mentioned. The drive gear transmits the power of the motor to a roller gear fixed to the core shaft 82a of the pressure roller 82. In the conventional image forming apparatus, since the fixing unit 8 needs to be taken out to the right from the fixing unit housing portion 2e, the drive gear cannot be disposed on the right side of the roller gear. Therefore, depending on the position where the drive gear is disposed, a load (a component force in a direction in which the pressure roller 82 is separated from the fixing roller 81) that reduces the nip pressure may act on the roller gear.

In contrast, in the present embodiment, the drive gear can be disposed on either the front, rear, left, and right sides of the roller gear, and therefore the drive gear can be disposed at an appropriate position where the nip pressure is not reduced.

In the present embodiment, the image forming apparatus 1 includes the driving mechanism 60 for moving the IH heating unit 50, and the driving mechanism 60 is configured to be able to drive the IH heating unit 50 between a preset heating position at which the fixing roller 81 of the fixing unit 8 attached to the fixing unit housing portion 2e can be heated and a retracted position moved to the left side of the heating position (radially outward of the fixing roller 81) and retracted to the outer side of the insertion and extraction path of the fixing unit 8.

The driving mechanism 60 is configured to be capable of selectively switching the position of the IH heating unit 50 between the heating position and the retracted position in conjunction with the opening/closing operation of the second maintenance door 14 as an operation unit operable by the user.

According to this configuration, when the fixing unit 8 needs to be inserted and removed, the IH heating unit 50 can be moved to the retracted position by operating the operation portion, and when the fixing process by the fixing unit 8 is executed, the IH heating unit 50 can be moved to the heating position by operating the operation portion. Therefore, even if the insertion/removal direction of the fixing unit 8 is set to the front-rear direction, the fixing unit 8 and the IH heating unit 50 do not interfere with each other when the fixing unit 8 is inserted/removed.

In the present embodiment, the driving mechanism 60 is configured to position the IH heating unit 50 at the heating position in a state where the second maintenance door 14 as the operating portion is fully closed, and to position the IH heating unit 50 at the retracted position in a state where the second maintenance door 14 is at a predetermined open position where the fixing unit 8 can be inserted from and removed from the insertion and removal opening (in the example of the present embodiment, a state rotated by 90 ° from the fully closed state).

According to this configuration, the user can move the IH heating unit 50 to an appropriate position in accordance with the opening and closing operation of the second maintenance door 14 without performing an operation of positioning the IH heating unit 50 at any one of the heating position and the retracted position. That is, when the user opens the second maintenance door 14 to perform the insertion and extraction work of the fixing unit 8, the IH heating unit 50 is moved to the retracted position by the driving mechanism 60, and therefore, the user does not need to perform the work of moving the IH heating unit 50 to the retracted position separately from the work of opening the second maintenance door 14. When the user attaches the fixing unit 8 to the fixing unit housing 2e and completely closes the second maintenance door 14, the IH heating unit 50 is moved to the heating position by the driving mechanism 60. Therefore, the user does not need to perform the operation of moving the IH heating unit 50 to the heating position separately from the operation of closing the second maintenance door 14. Therefore, the work load at the time of inserting and removing the fixing unit 8 can be reduced.

In the present embodiment, the IH heating unit 50 is used as a heating section for heating the fixing roller 81. The IH heating unit 50 has: a holder 50a having a recess 50g, the recess 50g receiving a surface portion of the fixing roller 81 on a side opposite to the nip portion N side; a plurality of IH coils 50b supported by the holder 50 a; and an arch core 50c covering the IH coil 50 b.

In this way, when the IH heating unit 50 is used, the outer peripheral surface of the fixing roller 81 on the side opposite to the nip portion N enters the recess 50g of the holder 50 a. Therefore, when the fixing unit 8 is inserted and removed in the axial direction, the fixing unit 8 and the IH heating unit 50 easily interfere with each other. In such a configuration, it is particularly effective to employ the driving mechanism 60 capable of moving the IH heating unit 50 to the retracted position in order to avoid interference.

In the present embodiment, the image forming apparatus main body 2 includes: a drum unit housing section 2c that houses the drum unit 20 so as to be freely inserted and removed in the same direction as the insertion and removal direction of the fixing unit 8; and a developing unit housing portion 2d configured to house the developing unit 30 (see fig. 1) so as to be insertable and removable in the same direction as the insertion and removal direction of the fixing unit 8. The opening for inserting and removing the fixing unit 8 in the fixing unit housing 2e, the opening for inserting and removing the drum unit 20 in the drum unit housing 2c, and the opening for inserting and removing the developing unit 30 in the developing unit housing 2d are opened on the same side (front side) of the image forming apparatus main body 2.

With this configuration, the user can perform maintenance work on the drum unit 20, the developing unit 30, and the fixing unit 8 from the front side of the image forming apparatus main body 2. Therefore, it is not necessary to perform complicated operations such as maintenance operations of the drum unit 20 and the developing unit 30 from the front side of the image forming apparatus main body 2 and maintenance operations of the fixing unit 8 from the right side of the image forming apparatus main body 2 as in the conventional art. Therefore, the maintenance operation of the image forming apparatus 1 can be facilitated.

Other embodiments

In the above embodiment, the link mechanism (the driving mechanism 60) is adopted as the driving portion for driving the IH heating unit 50 to the heating position and the retracted position, but the present invention is not limited thereto. The driving unit may have a motor as a driving source. In this case, the second maintenance door 14 may be interlocked with a drive switch of the motor. Further, a command for driving the motor may be issued from an operation panel of the image forming apparatus main body 2.

In the above embodiment, the upper engaging groove 50e and the lower engaging groove 50f are formed in the positioning block portion 50d of the IH heating unit 50, and the respective engaging grooves 50e and 50f are engaged with the upper engaging pin 85 and the lower engaging pin 86 of the fixing unit 8, respectively, but the present invention is not limited thereto, and for example, the lower engaging groove 50f and the lower engaging pin 86 may be eliminated, and the positioning may be performed only by the upper engaging groove 50e and the upper engaging pin 85. That is, the positioning structure may be any structure as long as the distance between the inner surface of the recess 50g of the holder 50a and the outer peripheral surface of the fixing roller 81 can be limited to a predetermined distance.

In the above embodiment, the fixing roller 81 has been described as an example of the rotary fixing member, but the rotary fixing member is not limited to this, and may be an endless fixing belt. In the above embodiment, the pressure roller 82 is described as an example of the rotary pressing member, but the rotary pressing member is not limited to this, and the rotary pressing member may be an endless pressure belt.

Industrial applicability of the invention

As described above, the present invention is useful for an image forming apparatus, and is particularly useful when applied to a printer, a facsimile machine, a copying machine, a complex Machine (MFP), or the like.