JP7432108B2 - image forming device - Google Patents

Description

The present invention relates to an image forming apparatus equipped with a fixing device.

2. Description of the Related Art Conventionally, image forming apparatuses that include a flapper used in double-sided printing are known (see Patent Document 1). The flapper is rotatable between a position where it guides the sheet discharged from the nip section of the fixing device out of the main body casing and a position where it restricts the sheet drawn into the main body casing from moving toward the nip section. ing. The flapper is rotatably supported by a plate of the fixing device.

JP2009-286583A

Incidentally, for the purpose of removing sheets that are jammed in the fixing device, it is conceivable to provide a plurality of movable guides that can rotate like flappers on the downstream side of the nip portion in the sheet conveyance direction. In this case, if the plurality of movable guides are supported by separate members, the positional accuracy of each movable guide may deteriorate.

Therefore, an object of the present invention is to improve the positional accuracy of a plurality of movable guides provided on the downstream side of the nip portion in the sheet conveyance direction.

In order to solve the above problems, an image forming apparatus according to the present invention includes a first fixing member, a second fixing member that forms a nip portion between the first fixing member, and a second fixing member that forms a nip portion between the first fixing member and the first fixing member. a first movable guide that is disposed downstream of the sheet and guides the sheet; and a second movable guide that guides the sheet downstream of the nip portion and upstream of the first movable guide in the conveyance direction. , a support member in which a first shaft support rotatably supports the first movable guide and a second shaft support rotatably supports the second movable guide are integrally formed.

According to this configuration, since the plurality of movable guides are supported by one support member, the positional accuracy of the plurality of movable guides can be improved, for example, compared to a structure in which each of the plurality of movable guides is supported by a separate member.

The image forming apparatus further includes a spring that biases one of the first fixing member and the second fixing member toward the other member, and an arm that supports the one member, the arm supporting the one member. An arm having a spring engagement part that engages with a spring, and a support shaft rotatably supporting the arm, and the support member is configured to connect the support shaft and the spring engagement part of the arm. It may have a 1st clamping part which clamps the part between in the axial direction of the support shaft.

According to this, since the arm is held between the first holding parts of the support member in the axial direction, it is possible to suppress the arm from tilting in the axial direction.

Further, the image forming apparatus may include a bush disposed between the support shaft and the arm, and the bush may have a second holding part that holds the arm in the axial direction.

According to this, since the second clamping portion of the bush also clamps the arm in the axial direction, tilting of the arm in the axial direction can be further suppressed.

Further, the image forming apparatus includes a main body housing and a first switchback roller capable of forward and reverse rotation, which conveys the sheet toward the outside of the main body housing when rotated in the forward direction, and conveys the sheet toward the outside of the main body housing when rotated in the reverse direction. a first switchback roller that pulls the sheet into the housing; a first position that guides the sheet discharged from the nip toward the first switchback roller; a first flapper that is rotatable between a second position and a second position that restricts the sheet drawn into the nip portion from moving toward the nip portion, and the first movable guide has the first flapper. Good too.

Further, the second movable guide may guide the sheet from the nip portion toward the first flapper.

Further, the image forming apparatus includes a second switchback roller capable of forward and reverse rotation, which transports the sheet toward the outside of the main body casing during forward rotation, and transports the sheet within the main body casing during reverse rotation. a second switchback roller that pulls in the sheet, a third position that guides the sheet discharged from the nip toward the first switchback roller, and a third position that guides the sheet discharged from the nip toward the second switchback roller. a second flapper rotatable between a second flapper and a fourth position for guiding the first movable guide toward the base member; , the first flapper is supported by the base member so as to be rotatable about a second axis different from the first axis, and the first flapper is rotatably supported by the base member, and the first flapper is pivotable about the first axis of the first movable guide. The rotation trajectory and the rotation trajectory of the second flapper overlap, the first flapper has a plurality of first ribs that guide the sheet, and the second flapper has a plurality of first ribs that guide the sheet. The plurality of second ribs include a small rib having a predetermined length from the center of rotation to the tip of the second flapper, and a small rib having a predetermined length from the center of rotation to the tip of the second flapper. a large rib having a length greater than the predetermined length, and when the first movable guide rotates about the first axis, the tip of the large rib is located between the two first ribs. It may be configured such that it is inserted between the two.

According to this, since the first flapper and the second flapper can be arranged close to each other, it is possible to downsize the image forming apparatus.

Further, the image forming apparatus includes a rear guide that guides the sheet discharged from the nip portion between the sheet and the first flapper and then toward the second flapper, and the rear guide is configured to It has a plurality of third ribs that guide the sheet, and when the second flapper is located at the fourth position, the tip of the second rib is configured to fit between the two third ribs. You can leave it there.

According to this, the rear guide and the second flapper can be arranged close to each other, so that the image forming apparatus can be downsized. Further, it is possible to prevent the sheet discharged from the nip portion from getting stuck between the rear guide and the second flapper.

Further, when the first flapper is located at the second position, the tip of the first rib may be configured to fit between the two third ribs.

According to this, the rear guide and the first flapper can be arranged close to each other, so it is possible to downsize the image forming apparatus. Furthermore, it is possible to prevent the sheet drawn into the main body casing by the first switchback roller from getting stuck between the first flapper and the rear guide.

According to the present invention, it is possible to improve the positional accuracy of the plurality of movable guides provided on the downstream side of the nip portion in the sheet conveyance direction.

1 is a diagram showing a color printer according to an embodiment of the present invention. It is an enlarged view showing the structure around the first flapper and the second flapper. They are a diagram (a) showing a state in which the first movable guide is located at a sixth position, and a diagram (b) showing an enlarged view of the structure around the nip portion. FIG. 2 is a perspective view showing the structure of the fixing device on the downstream side in the sheet conveyance direction. It is an exploded perspective view showing a first movable guide, a second movable guide, a rear guide, and a support member. FIG. 3 is an exploded perspective view showing a fixing frame, an arm, and the like. It is a figure showing the relationship between an arm, a support member, etc. It is a sectional view showing a support member and a holding part of a bush. FIG. 3 is a perspective view showing the relationship between a second flapper, a rear guide, and the like. FIG. 6 is a rear view showing the relationship between the second flapper, the rear guide, and the like. It is a perspective view showing an outer chute lower. It is a perspective view showing a 1st movable guide. It is a figure which shows the sponge arrange|positioned between a front chute and a storage box.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings as appropriate.
As shown in FIG. 1, a color printer 1 as an example of an image forming apparatus is configured to be able to form images on both sides of a sheet S, and includes a main body casing 2 and a main body casing 2 disposed inside the main body casing 2. The image forming apparatus includes a supply section 3, an image forming section 4, a fixing device 8, and a conveyance section 9.

The main body case 2 has a discharge tray 21 on the upper surface. The main body case 2 has a manual feed tray 2A on the front side. The main body case 2 has a rear cover 2B on the back side. The manual feed tray 2A is rotatable between a first closed position shown in FIG. 1 and a first open position in which a sheet S can be placed. The sheet S placed on the manual feed tray 2A is conveyed to the image forming section 4 by the manual feed section 2C.

The rear cover 2B is rotatable between a second closed position shown in FIG. 1 and a second open position for opening an opening provided on the back surface of the main body housing 2. Thereby, the sheet S can be conveyed straight in the front-rear direction from the manual feed tray 2A located at the first open position, and discharged onto the rear cover 2B located at the second open position. In the following description, conveying the sheet S straight in the front-rear direction from the manual feed tray 2A is also referred to as "straight conveyance." Note that the manual tray 2A and the rear cover 2B are positioned at each position by the manual tray 2A and the rear cover 2B coming into contact with a part of the main body casing 2.

The supply section 3 is provided in the lower part of the main body housing 2 and includes a supply tray 31 that accommodates sheets S, and a supply mechanism 32 that supplies the sheets S in the supply tray 31 to the image forming section 4.

The image forming section 4 has a function of transferring a toner image onto a sheet S to form an image, and includes an exposure device 5, four process cartridges 6, and a transfer unit 7.

The exposure device 5 is disposed in the upper part of the main body casing 2, and includes a light source, a polygon mirror, etc. (not shown). The exposure device 5 exposes the surface of the photoreceptor drum 61 by scanning the surface of the photoreceptor drum 61 at high speed with a light beam based on image data, which is shown by a dashed line.

The process cartridge 6 includes a photosensitive drum 61, a charger 62, and a developing roller 63. The four process cartridges 6 contain toner of each color: yellow, magenta, cyan, and black.

The transfer unit 7 includes a drive roller 71, a driven roller 72, a conveyor belt 73, and four transfer rollers 74. The conveyor belt 73 is an endless belt, and is stretched between the drive roller 71 and the driven roller 72. A transfer roller 74 is arranged inside the conveyor belt 73 so as to sandwich the conveyor belt 73 between it and the corresponding photoreceptor drum 61 .

The charger 62 charges the surface of the photoreceptor drum 61. After that, the exposure device 5 exposes the surface of the photoreceptor drum 61 to form an electrostatic latent image on the surface of the photoreceptor drum 61 based on the image data.

The developing roller 63 supplies toner to the electrostatic latent image formed on the photoreceptor drum 61. As a result, a toner image is formed on the photoreceptor drum 61. Thereafter, when the sheet S is conveyed between the photoreceptor drum 61 and the transfer roller 74 by the conveyor belt 73, the toner image on the photoreceptor drum 61 is transferred to the sheet S.

The fixing device 8 is a device that thermally fixes the toner image on the sheet S. Details of the fixing device 8 will be described later.

The conveying section 9 is configured to convey the sheet S discharged from the fixing device 8 to the outside of the main body housing 2 or toward the image forming section 4 again. The conveyance section 9 includes a first conveyance path 91, a second conveyance path 92, a reconveyance path 93, a first conveyance roller 94, a second conveyance roller 95, a first switchback roller SR1, and a second switch. It includes a back roller SR2, a plurality of re-conveyance rollers 96, a first flapper FL1, and a second flapper FL2.

The first conveyance path 91 is a path that guides the sheet ejected from the fixing device 8 toward the ejection tray 21 . The second conveyance path 92 is a path that guides the sheet discharged from the fixing device 8 toward the discharge tray 21 via a route different from the first conveyance path 91 . The re-conveyance path 93 is a path that guides the sheet S drawn into the main body casing 2 by a first switchback roller SR1, etc., which will be described later, to the supply mechanism 32 on the upstream side of the image forming section 4. The re-conveyance roller 96 is a roller that conveys the sheet S in the re-conveyance path 93 toward the supply mechanism 32 , and is provided in the re-conveyance path 93 .

The first conveyance roller 94 is provided in the fixing device 8 . The first conveyance roller 94 conveys the sheet S on which the toner image is thermally fixed toward the second flapper FL2.

The second conveyance roller 95, the first switchback roller SR1, and the second switchback roller SR2 are rollers that can rotate in forward and reverse directions. The second conveyance roller 95, the first switchback roller SR1, and the second switchback roller SR2 convey the sheet S to the outside of the main body casing 2, specifically toward the discharge tray 21, when rotating in the forward direction, and transport the sheet S toward the main body casing 2 when rotating in the reverse direction. Pull the sheet S into the body 2.

The second conveyance roller 95 and the first switchback roller SR1 are provided on the first conveyance path 91. The first switchback roller SR1 is arranged closer to the discharge tray 21 than the second conveyance roller 95. The second switchback roller SR2 is provided on the second conveyance path 92.

As shown in FIG. 2, the first flapper FL1 is rotatable between a first position shown by a solid line and a second position shown by a two-dot chain line. When the first flapper FL1 is located at the first position, the first flapper FL1 guides the sheet S discharged from the nip portion NP of the fixing device 8, which will be described later, toward the first switchback roller SR1. When the first flapper FL1 is located at the second position, the first flapper FL1 restricts the sheet S drawn into the main body casing 2 by the first switchback roller SR1 or the second switchback roller SR2 from moving toward the nip portion NP. .

The second flapper FL2 is rotatable between a third position shown by a solid line and a fourth position shown by a two-dot chain line. When the second flapper FL2 is located at the third position, the second flapper FL2 guides the sheet S discharged from the nip portion NP toward the first switchback roller SR1. When the second flapper FL2 is located at the fourth position, the second flapper FL2 guides the sheet S discharged from the nip portion NP toward the second switchback roller SR2.

The first flapper FL1 is urged from the first position to the second position by a spring (not shown). The first flapper FL1 is positioned at the second position by contacting a rear guide 300, which will be described later. Then, the sheet S discharged from the nip portion NP pushes the first flapper FL1 against the urging force of the spring, so that the first flapper FL1 rotates from the second position to the first position, and the sheet S When the end comes off the first flapper FL1, the first flapper FL1 is configured to rotate from the first position to the second position by the urging force of the spring. The second flapper FL2 can be switched between a third position and a fourth position by a control section (not shown).

When performing single-sided printing or double-sided printing at a predetermined printing speed, the second flapper FL2 is arranged at the third position. Here, the unit of printing speed is PPM, that is, sheets per minute. Further, when double-sided printing is performed at a printing speed higher than a predetermined printing speed, the second flapper FL2 is switched between the third position and the fourth position for each sheet S by the control unit. In the following description, double-sided printing performed at a printing speed higher than a predetermined printing speed is also referred to as "high-speed double-sided printing."

In high-speed double-sided printing, for example, after guiding the first sheet S printed on one side to the first conveyance path 91 by the second flapper FL2 located at the third position, the second flapper FL2 is moved to the fourth position. , and the second sheet S with one side printed is guided to the second conveyance path 92 by the second flapper FL2 located at the fourth position. Thereafter, when the first switchback roller SR1 and the second conveyance roller 95 are reversely rotated to draw the first sheet S into the main body housing 2, the second flapper FL2 is switched to the third position, and the second flapper FL2 is switched to the third position. The sheet S is guided to the re-conveyance path 93.

After that, when the second switchback roller SR2 is reversely rotated to draw the second sheet S into the main body casing 2, the second flapper FL2 is maintained at the third position, so that two sheets The second sheet S is guided to the re-conveyance path 93. Note that when drawing the second sheet S into the main body casing 2, the second flapper FL2 may be switched to the fourth position.

As shown in FIG. 3A, the fixing device 8 includes two heaters H, a first fixing member 81, a second fixing member 82, a first movable guide 100, a second movable guide 200, and a rear It includes a guide 300 and a support member 400. The first movable guide 100, the second movable guide 200, the rear guide 300, and the support member 400 are made of resin or the like.

The first fixing member 81 has a rotatable roller. The two heaters H are heaters that heat the first fixing member 81 and are arranged inside the first fixing member 81. The relationship among the circumferential speed V1 of the conveyance belt 73, the circumferential speed V2 of the first fixing member 81, the circumferential speed V3 of the first conveyance roller 94, and the circumferential speed V4 of the second conveyance roller 95 is as follows.
V3>V1>V4>V2
Note that the relationship between the circumferential speeds is not limited to this. For example, the peripheral speed of the second conveyance roller 95 may be greater than or equal to the peripheral speed of the conveyance belt 73.

As shown in FIG. 3B, the second fixing member 82 is a member that forms a nip portion NP with the first fixing member 81. As shown in FIG. The second fixing member 82 includes an endless belt 82A and two pads 82B that sandwich the belt 82A between the first fixing member 81 and the first fixing member 81. Further, the second fixing member 82 includes a resin holder 82C that holds the two pads 82B, and a metal stay 82D that supports the holder 82C.

The first movable guide 100 is a guide that guides the sheet S, and is disposed downstream of the nip portion NP in the conveyance direction of the sheet S. The first movable guide 100 includes the first flapper FL1 described above and a base member 110 that rotatably supports the first flapper FL1.

The base member 110 is supported by the support member 400 so as to be rotatable about the first axis X1. The first flapper FL1 is supported by the base member 110 so as to be rotatable about a second axis X2 different from the first axis X1.

The base member 110 is rotatable between a fifth position shown in FIG. 2 and a sixth position shown in FIG. 3(a). When discharging the sheet S to the discharging tray 21 shown in FIG. 2, the base member 110 is arranged at the fifth position. When performing straight conveyance in which the sheet S is discharged from the back side of the color printer 1, the base member 110 is arranged at the sixth position.

The base member 110 is urged against the rear cover 2B by a spring (not shown). Thereby, the base member 110 rotates in conjunction with opening and closing of the rear cover 2B. Then, when the rear cover 2B is located at the second closed position, the base member 110 is positioned at the fifth position by contacting the rear cover 2B. Specifically, the base member 110 is positioned at the fifth position by being supported by the main body casing 2 via the rear cover 2B.

Moreover, when the rear cover 2B is located at the second open position shown in FIG. 3(a), the base member 110 is positioned at the sixth position by contacting the rear cover 2B. Specifically, the base member 110 is positioned at the sixth position by being supported by the main body casing 2 via the rear cover 2B.

More specifically, the rear cover 2B has a rear cover chute RS that guides the seat S. The base member 110 contacts the rear cover chute RS regardless of whether it is located at the fifth position or the sixth position.

When the base member 110 is located at the fifth position, the first flapper FL1 contacts the rear guide 300 and is positioned at the second position described above. During printing, the first flapper FL1 rotates from the second position to the first position about the second axis X2 every time it is pushed by the sheet S discharged from the nip portion NP.

The rotation trajectory T1 of the first movable guide 100 about the first axis X1 and the rotation trajectory T2 of the second flapper FL2 overlap. Specifically, the rotation locus T1 of the first movable guide 100 overlaps with the second flapper FL2 located at the third position. As a result, if the first movable guide 100 is rotated from the fifth position to the sixth position when the second flapper FL2 is located at the third position, there is a risk that the first movable guide 100 will interfere with the second flapper FL2. However, in this embodiment, interference is suppressed by the structure described later.

The second movable guide 200 has a guide surface F1 that guides the sheet S downstream of the nip portion NP and upstream of the first movable guide 100 in the conveyance direction of the sheet S. The guide surface F1 is arranged between the nip portion NP and the first flapper FL1 in the conveyance direction of the sheet S, and guides the sheet S from the nip portion NP toward the first flapper FL1. The second movable guide 200 rotatably supports the second roller 94B, which is disposed on the lower side of the first roller 94A and the second roller 94B that constitute the first conveyance roller 94 described above.

Here, the driving force of a fixing motor (not shown) for applying driving force to the first fixing member 81 is transmitted to the second roller 94B. Specifically, the driving force of the fixing motor is applied to a first idle gear, a gear fixed to the end of the first fixing member 81, a second idle gear, a third idle gear G1 shown in FIG. 4, and an end of the second roller 94B. It is transmitted to the second roller 94B via a roller gear G2 fixed to the section.

The second movable guide 200 is supported by the support member 400 so as to be rotatable about a third axis X3 different from the first axis X1. The second movable guide 200 has two positions: a seventh position shown in FIG. 3A, where the second roller 94B contacts the first roller 94A, and an eighth position, not shown, where the second roller 94B separates from the first roller 94A. It is possible to rotate between.

The second movable guide 200 is arranged at the eighth position when the sheet S is jammed between the first roller 94A and the second roller 94B. Thereby, the distance between the first roller 94A and the second roller 94B is widened, and the sheet S stuck between the first roller 94A and the second roller 94B can be easily taken out.

The second movable guide 200 is positioned at the seventh position by contacting the rear guide 300. The second movable guide 200 is located at the eighth position by contacting the first movable guide 100 and the like located at the sixth position.

The rear guide 300 is a guide that guides the sheet S discharged from the nip portion NP between it and the first flapper FL1, and then guides it toward the second flapper FL2. The rear guide 300 rotatably supports the first roller 94A.

As shown in FIGS. 4 and 5, the rear guide 300 has a plurality of third ribs R3 that guide the seat S. The plurality of third ribs R3 are arranged at intervals in the width direction of the sheet S. Note that in the following description, the width direction of the sheet S is also simply referred to as the "width direction." The rear guide 300 is fixed to a fixing frame 500, which will be described later, and more specifically, to an upper frame 520 shown in FIG. 6.

The first flapper FL1 has a plurality of first ribs R1 that guide the sheet S. The plurality of first ribs R1 are arranged at intervals in the width direction. The first rib R1 extends in a predetermined direction from the second axis X2, specifically in a direction away from the base member 110. When the first flapper FL1 is located at the second position, the tip R11 of the first rib R1 is between the two third ribs R3. Specifically, when the first flapper FL1 is located at the second position, the tips R11 of the majority of the first ribs R1 are respectively located between any two of the third ribs R3. There is. In other words, the first rib R1 of the first flapper FL1 located at the second position overlaps with the third rib R3 when projected in the width direction.

The first flapper FL1 has a connecting portion FL11 that connects two first ribs R1 located at the center in the width direction. The connecting portion FL11 is arranged away from the tip R11 of the first rib R1 in the direction from the base end to the tip R11 of the first rib R1. Here, the base end of the first rib R1 indicates the end of the first rib R1 on the second axis X2 side. As a result, a recess CV that is recessed from the distal end toward the proximal end is formed at the center of the first flapper FL1 in the width direction.

As shown in FIG. 5, one support member 400 is arranged at one end and the other end of the first movable guide 100 and the second movable guide 200 in the width direction. A first shaft support 410 that rotatably supports the first movable guide 100 and a second shaft support 420 that rotatably supports the second movable guide 200 are integrally formed in the support member 400. . In other words, the support member 400 is not a member in which a member having a first pivot support and a member having a second pivot support are assembled together with screws, etc., but a member in which the first pivot support 410 and the second pivot support 420 are integrally assembled. It is a single piece formed.

The first shaft support 410 is a cylindrical projection. The base member 110 has a hole 111 at one end and the other end in the width direction, into which the first shaft support 410 is inserted.

The second shaft support 420 is formed into a semi-cylindrical shape. The second movable guide 200 has a boss 210 rotatably supported on the inner peripheral surface of the second shaft support 420 at one end and the other end in the width direction. The support member 400 is fixed to a fixing frame 500 (described later), more specifically, to a side frame 510.

As shown in FIG. 6, the fixing device 8 includes a fixing frame 500, two arms 620 rotatably supported by the fixing frame 500, and two springs 630 provided between the arms 620 and the fixing frame 500. It also has: Fixing frame 500, arm 620, and spring 630 are made of metal or the like.

Fixing frame 500 includes two side frames 510, an upper frame 520, a lower frame 530, and a support shaft 540. One side frame 510 is arranged at one end and the other end of the first fixing member 81 in the width direction.

The side frame 510 has a support hole 511 that supports the first fixing member 81 via a bearing (not shown), and the second fixing member 82 can be moved in opposing directions in which the first fixing member 81 and the second fixing member 82 face each other. It has a support groove 512 that supports the spring 630, and an engaging portion 513 that engages with the spring 630.

Each axial end of the upper frame 520, lower frame 530, and support shaft 540 is fixed to the side frame 510, respectively. Lower frame 530 and support shaft 540 are arranged below upper frame 520. Support shaft 540 rotatably supports arm 620.

As shown in FIG. 7, the arm 620 has a support hole 621 that supports the second fixing member 82 and a spring engaging portion 622 that engages with the spring 630. Specifically, the inner peripheral edge forming the support hole 621 supports the stay 82D via the resin buffer member BF. Thereby, the biasing force of the spring 630 is applied to each pad 82B via the arm 620, the buffer member BF, the stay 82D, and the holder 82C shown in FIG. 3(a). The arm 620 is formed into a substantially L shape and has the above-mentioned spring engaging portion 622 at one end. A resin bush 640 is provided at the other end of the arm 620. The arm 620 is rotatably supported by the support shaft 540 via a bush 640.

The bush 640 is a member that prevents the metal support shaft 540 and the arm 620 from rubbing against each other, and is disposed between the support shaft 540 and the arm 620. The support hole 621 is arranged between the spring engaging portion 622 and the bush 640 of the arm 620.

The spring 630 is a spring that urges the second fixing member 82 toward the first fixing member 81 . Specifically, the spring 630 biases the second fixing member 82 toward the first fixing member 81 via the arm 620.

As shown in FIGS. 7 and 8, the support member 400 extends the portion of the arm 620 between the support shaft 540 and the spring engaging portion 622, specifically, the portion around the support hole 621 in the axial direction of the support shaft 540. It has a first holding part 430 that is held between the two sides. More specifically, the first clamping portion 430 axially clamps a portion of the arm 620 located opposite to the bush 640 with the support hole 621 interposed therebetween. The bush 640 has a second clamping portion 641 that clamps the arm 620 in the axial direction.

As shown in FIGS. 9 and 10, the color printer 1 further includes a main body guide 22 for forming the second transport path 92 shown in FIG. 2 described above. The main body guide 22 rotatably supports the second switchback roller SR2 described above, and also supports the second flapper FL2 so as to be rotatable about the fourth axis X4.

The second flapper FL2 has a plurality of second ribs R2 that guide the sheet S. The plurality of second ribs R2 are arranged at intervals in the width direction. The second rib R2 extends downward from the fourth axis X4, which is the center of rotation of the second flapper FL2. The tips of the second ribs R2, specifically, the tips R211 of the small ribs R21 and the tips R221 of the large ribs R22, which will be described later, are connected to the two third ribs when the second flapper FL2 is located at the fourth position shown in FIG. It is between R3. Specifically, when the second flapper FL2 is located at the fourth position, the tips of the majority of the second ribs R2 are located between any two of the third ribs R3. . In other words, the second rib R2 of the second flapper FL2 located at the fourth position overlaps the third rib R3 when projected in the width direction.

The plurality of second ribs R2 include small ribs R21 and large ribs R22. The small rib R21 has a predetermined length L1 from the fourth axis X4, which is the center of rotation of the second flapper FL2, to the tip. The large rib R22 has a length L2 from the fourth axis X4 to the tip, which is larger than the predetermined length L1.

Two large ribs R22 are arranged at the center of the second flapper FL2 in the width direction. A plurality of small ribs R21 are arranged on one side and the other side in the width direction of the two large ribs R22. By making the second rib R2 at the center in the width direction the large rib R22, for example, when conveying the sheet S straight in the front-rear direction, the second rib R2 at the center in the width direction can be conveyed straight in the front-rear direction. By rotating the second flapper FL2 from the fourth position to the third position, the sheet S can be sent out toward the back of the color printer 1 by the second flapper FL2.

When the first movable guide 100 rotates around the first axis X1 when the second flapper FL2 is located at the third position, the tip of the large rib R22 is connected to the two first ribs of the first flapper FL1. It is designed to fit between R1. That is, as shown in FIG. 3(a), when the first movable guide 100 rotates around the first axis X1 when the second flapper FL2 is located at the third position, the large rib R22 of the second flapper FL2 passes relatively within the recess CV shown in FIG. 4 formed at the tip of the first flapper FL1, that is, between the two first ribs R1 located at the center in the width direction. It is possible to suppress interference with flapper FL2.

As shown in FIG. 2, the fixing device 8 further includes a front chute 83 and an outer chute lower 84. The front chute 83 is a member that guides the sheet S to the nip portion NP. The front chute 83 is arranged upstream of the nip portion NP in the conveyance direction.

The outer chute lower 84 is arranged between the second fixing member 82 and the base member 110. The outer chute lower 84 is fixed to a lower frame 530 shown in FIG. 6.

As shown in FIG. 11, the outer chute lower 84 has a positioning groove 84A for positioning the base member 110 in the axial direction. As shown in FIG. 12, the base member 110 has a positioning rib 112 that fits into the positioning groove 84A of the outer chute lower 84. When the base member 110 is located at the fifth position, the positioning rib 112 enters the positioning groove 84A, so that the base member 110 is positioned in the axial direction.

As shown in FIG. 13, the color printer 1 further includes a fan FN, a patch sensor PS, a board BD, a storage box BX, and a sponge SP. The fan FN is a fan that discharges air inside the main body casing 2 to the outside. Fan FN is arranged above fixing device 8 .

The patch sensor PS is a sensor for detecting a test toner image formed on the conveyor belt 73, a so-called patch. Patch sensor PS is arranged at the downstream end of conveyor belt 73 in the conveyance direction. Furthermore, the patch sensor PS is arranged below the front chute 83.

The substrate BD is provided with a power supply circuit including an AC/DC converter that converts an AC voltage input from a commercial power source into a DC voltage. The power supply circuit supplies power to various devices and units within the color printer 1, such as the fixing device 8. The substrate BD is housed in the housing box BX.

The storage box BX is arranged below the conveyor belt 73 and the fixing device 8. The sponge SP is arranged between the front chute 83 and the storage box BX, and is sandwiched between the front chute 83 and the storage box BX.

Here, in a configuration in which the sponge SP is not provided, the air heated in the fixing device 8 passes through the route shown by the broken line arrow in the figure, specifically, between the front chute 83 and the storage box BX, and then passes through the patch sensor PS. It may pass nearby and be sucked into the fan FN. In this case, there is a possibility that dew condensation may occur on the sensor substrate within the patch sensor PS. Furthermore, there is a possibility that water droplets condensed on the outer surface of the accommodation box BX may flow into the interior through the gaps in the accommodation box BX and adhere to the substrate BD within the accommodation box BX.

On the other hand, in this embodiment, since the space between the front chute 83 and the storage box BX is closed with the sponge SP, the air heated in the fixing device 8 is routed along the route shown by the solid arrow in the figure. passes between the front chute 83 and the second fixing member 82 and rises, passes over the front chute 83, and is sucked into the fan FN. Therefore, in this embodiment, it is possible to suppress the occurrence of dew condensation on the sensor substrate in the patch sensor PS and the outer surface of the storage box BX. Note that, instead of the sponge SP, other elastic members such as a film or rubber may be provided.

According to the above, the following effects can be obtained in this embodiment.
Since one end side in the width direction of the first movable guide 100 and the second movable guide 200 is supported by one support member 400, compared to, for example, a configuration in which one end side in the width direction of the two movable guides is supported by separate members, The positional accuracy of the first movable guide 100 and the second movable guide 200 can be improved.

Since the arm 620 is held between the first holding part 430 of the support member 400 and the second holding part 641 of the bush 640 in the axial direction, it is possible to suppress the arm 620 from tilting in the axial direction.

When the first movable guide 100 rotates around the first axis Since the flapper FL2 can be placed close to each other, the color printer 1 can be made smaller.

When the second flapper FL2 is located at the fourth position, the tip of the second rib R2 is configured to fit between the two third ribs R3, thereby bringing the rear guide 300 and the second flapper FL2 closer together. Therefore, the color printer 1 can be made smaller. Further, it is possible to prevent the sheet S discharged from the nip portion NP from entering between the rear guide 300 and the second flapper FL2 and becoming jammed.

When the first flapper FL1 is located at the second position, the tip R11 of the first rib R1 is configured to fit between the two third ribs R3, thereby bringing the rear guide 300 and the first flapper FL1 closer together. Since the color printer 1 can be arranged in a similar manner, the size of the color printer 1 can be reduced. Further, it is possible to prevent the sheet S drawn into the main body casing 2 by the first switchback roller SR1 from entering between the first flapper FL1 and the rear guide 300 and becoming jammed.

Since the second movable guide 200 is fixed to the metal side frame 510 via the support member 400 and the first fixing member 81 is fixed via a bearing, the second movable guide 200 is fixed to the side frame 510 made of metal. 200 and the number of parts up to the first fixing member 81 can be reduced, and the second movable guide 200 and the first fixing member 81 can be arranged with high accuracy with respect to the side frame 510. Therefore, the positional accuracy of the guide surface F1 of the second movable guide 200 with respect to the nip portion NP can be increased.

Since the rear guide 300 is fixed to the metal side frame 510 via the upper frame 520 and the first movable guide 100 is fixed via the support member 400, the rear guide 300 or The number of parts up to the first movable guide 100 can be reduced, and the rear guide 300 and the first movable guide 100 can be arranged with high accuracy with respect to the side frame 510. Therefore, the accuracy of the angle of the first movable guide 100 whose angle is determined by contacting the rear guide 300 can be increased. Similarly, the accuracy of the angle of the second movable guide 200 whose angle is determined by contacting the rear guide 300 can also be increased.

Note that the present invention is not limited to the embodiments described above, and can be utilized in various forms as exemplified below.
In the embodiment, the two movable guides (100, 200) are pivotally supported by the support member 400, but the present invention is not limited to this, and three or more movable guides may be pivotally supported by the support member. .

Although in the embodiment described above, the fixing device 8 includes the support member 400, the present invention is not limited thereto, and for example, the main body case may include the support member.

In the embodiment described above, a cylindrical roller with a built-in heater was used as an example of the first fixing member, but the present invention is not limited thereto. The first fixing member may be, for example, a pressure roller having a shaft and a rubber layer formed around the shaft, or an endless belt whose inner peripheral surface is heated by a heater. Good too. Alternatively, an external heating method or an IH (induction heating) method may be used in which a heater is disposed outside the first fixing member to heat the outer circumferential surface of the first fixing member. Alternatively, the second fixing member may be provided with a heater to indirectly heat the first fixing member that contacts the outer peripheral surface of the second fixing member. Further, the first fixing member and the second fixing member may each include a built-in heater. The second fixing member may be a pressure roller having a shaft and a rubber layer formed around the shaft.

The elements described in the embodiments and modifications described above may be implemented in any combination.

1 Color printer 81 First fixing member 82 Second fixing member 100 First movable guide 200 Second movable guide 400 Support member 410 First shaft support 420 Second shaft support NP Nip portion S Sheet

Claims (11)

The main body casing;
a fixing device disposed inside the main body housing;
The fixing device includes:
a first fixing member;
a second fixing member forming a nip portion with the first fixing member;
a first movable guide that is disposed downstream of the nip portion in the sheet conveyance direction and guides the sheet;
a second movable guide that guides the sheet downstream of the nip portion and upstream of the first movable guide in the conveyance direction;
a support member in which a first shaft support that rotatably supports the first movable guide and a second shaft support that rotatably supports the second movable guide are integrally formed;
a fixing frame ;
The fixing frame has a side frame that supports an end of the first fixing member in the width direction of the sheet,
The image forming apparatus is characterized in that the support member is made of resin and is fixed inside the side frame in the width direction . The fixing device includes:
a spring that biases the second fixing member toward the first fixing member ;
an arm that supports the second fixing member and has a spring engaging portion that engages with the spring;
a support shaft rotatably supporting the arm , the support shaft being fixed to the side frame ;
The side frame has an engaging portion that engages with the spring,
The image according to claim 1, wherein the support member has a first clamping part that clamps a portion of the arm between the support shaft and the spring engaging part in the axial direction of the support shaft. Forming device. The fixing device includes a bush disposed between the support shaft and the arm,
3. The image forming apparatus according to claim 2, wherein the bush has a second clamping part that clamps the arm in the axial direction. a first switchback roller capable of forward and reverse rotation, the first switchback roller conveying the sheet toward the outside of the main body casing when rotating in the forward direction, and drawing the sheet into the main body casing when rotating in the reverse direction; ,
a first position for guiding the sheet discharged from the nip portion toward the first switchback roller; and regulating the sheet drawn into the main body housing by the first switchback roller from heading toward the nip portion. a first flapper rotatable between a second position and a second position;
The image forming apparatus according to any one of claims 1 to 3, wherein the first movable guide includes the first flapper. The first movable guide has a base member that is supported by the first shaft support and rotates about the first shaft,
The image forming apparatus according to claim 4, wherein the first flapper is rotatably supported by the base member and is rotatable about a second shaft that is separate from the first shaft support. . The second movable guide guides the sheet from the nip portion toward the first movable guide , and is rotatable about a third axis by being supported by the second shaft support. The image forming apparatus according to any one of claims 1 to 5, further comprising a roller located at a position apart from three axes . a fixed guide fixed to the fixing frame and guiding the sheet downstream from the nip portion;
The fixed guide has a roller that sandwiches the sheet between it and the roller of the second movable guide,
The second movable guide is located between a position where the roller of the second movable guide and the roller of the fixed guide are in contact with each other and a position where the roller of the second movable guide is separated from the roller of the fixed guide. The image forming apparatus according to claim 6, wherein the image forming apparatus is rotatable. 8. The image forming apparatus according to claim 6, wherein the second movable guide includes a gear that transmits a driving force to the roller of the second movable guide. a second switchback roller capable of forward and reverse rotation, the second switchback roller conveying the sheet toward the outside of the main body casing when rotating in the forward direction and pulling the sheet into the main body casing when rotating in the reverse direction; ,
a third position in which the sheet discharged from the nip portion is guided toward the first switchback roller; and a fourth position in which the sheet discharged from the nip portion is guided toward the second switchback roller. a second flapper rotatable between;
The first movable guide is
a base member rotatably supported by the support member about a first axis;
the first flapper being rotatably supported by the base member around a second axis different from the first axis;
The rotation locus of the first movable guide about the first axis and the rotation locus of the second flapper overlap,
The first flapper has a plurality of first ribs that guide the sheet,
The second flapper has a plurality of second ribs that guide the sheet,
The plurality of second ribs are
a small rib having a predetermined length from the center of rotation to the tip of the second flapper;
a large rib whose length from the center of rotation to the tip of the second flapper is greater than the predetermined length;
According to claim 4 or 5, when the first movable guide rotates around the first axis, the tip of the large rib fits between two of the first ribs. image forming device. a fixed guide that guides the sheet discharged from the nip portion between the sheet and the first flapper and then toward the second flapper;
The fixed guide has a plurality of third ribs that guide the sheet,
The image forming apparatus according to claim 9 , wherein when the second flapper is located at the fourth position, a tip of the second rib is between two of the third ribs. 11. The image forming apparatus according to claim 10 , wherein when the first flapper is located at the second position, a tip of the first rib is between two of the third ribs.

Images