JP7567248B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming device.

As disclosed in Patent Document 1, there is a known image forming device that includes a discharge path that guides transported paper to a paper discharge tray, a re-transport path that branches off from the discharge path, and a switching member that can move between a first position that guides the paper to the discharge path and a second position that guides the paper to the re-transport path. The switching member is supported, for example, by a holding member that forms part of the discharge path.

In such an image forming device, the holding member is provided on the housing of the image forming device so that it can rotate between a closed position that forms part of the paper discharge path and an open position that opens the paper discharge path. When paper becomes jammed in the paper discharge path, the holding member can be rotated to the open position, making it easy to remove the jammed paper.

JP 2016-71224 A

However, in the above-mentioned configuration, for example, if the holding member rotates to the open position while the switching member is in the first position, if the holding member rotates while the position of the switching member relative to the holding member is maintained, the switching member may interfere with the paper in the paper discharge path, making it difficult to remove the paper.

The present invention has been made to solve the above problems, and provides an image forming device that can prevent the switching member from interfering with the paper in the paper discharge path when the holding member is rotated to the open position.

The image forming device that solves the above problems has the following features:

That is, the image forming device includes a housing having a paper discharge tray to which paper transported from an image forming unit is discharged, a first transport unit having a paper discharge path that guides paper transported from the image forming unit to the paper discharge tray, a second transport unit having a re-transport path branching off from the paper discharge path, a holding member supported by the housing so as to be rotatable between a closed position that forms at least a part of the paper discharge path and an open position that opens the paper discharge path, and a first posture that is rotatably held by the holding member and guides paper to the paper discharge path when the holding member is in the closed position. , a second position that guides the paper to the re-conveyance path, and a switching member whose relative position with respect to the holding member is changeable to a third position as the holding member rotates from the closed position to the open position, the rotation tip of the switching member in the third position is farther away from the rotation tip of the switching member in the second position than the rotation tip of the switching member in the first position, and the switching member in the third position does not interfere with the paper in the paper discharge path.

This prevents the switching member from interfering with paper in the paper discharge path when the holding member is rotated to the open position.

The device further includes an abutting member that abuts against the switching member when the holding member is in the closed position, thereby changing the switching member between the first position and the second position, and when the holding member rotates to the open position, the switching member moves away from the abutting member and changes to the third position by its own weight.

In this way, when the holding member is rotated to the open position, the switching member moves away from the abutting member, allowing the switching member to change to the third position regardless of the state of the abutting member.

The first conveying section also has a guide member that faces the switching member, and the center of rotation of the switching member moves in a direction away from the guide member as the holding member rotates from the closed position to the open position.

In this way, the center of rotation of the switching member moves away from the guide member as the holding member rotates from the closed position to the open position, making it easier for the switching member to change to the third position in which it does not interfere with the paper in the paper discharge path.

In addition, the rotation tip and the rotation center of the switching member are located on opposite sides of the rotation center of the holding member.

In this way, even if the pivot tip and pivot center of the switching member are located on opposite sides of the pivot center of the holding member, the switching member changes to the third position, preventing the switching member from interfering with paper in the paper discharge path when the holding member is rotated to the open position.

The device also includes a control unit that controls the operation of the abutment member, and the abutment member is displaceable between a first operating position that changes the switching member to the first position and a second operating position that changes the switching member from the first position to the second position by pressing the switching member, and the control unit displaces the abutment member to the first operating position when it determines that it is necessary to rotate the holding member to the open position.

As a result, when the holding member rotates to the open position and returns to the closed position, the amount of pressure applied to the switching member by the abutting member is reduced, making it easier for the switching member to be positioned in an appropriate position.

The contact member is supported by the housing.

This allows the switching member and the abutment member to be easily separated when the holding member is rotated to the open position.

The device further includes a regulating member that is provided between the housing and the holding member and that applies a sliding resistance to the holding member to regulate the rotational movement of the holding member when the holding member rotates between the closed position and the open position, the regulating member being located at one end or the other end of the holding member in a width direction perpendicular to the paper transport direction, and the abutment member being located at the other end or the other end of the holding member in the width direction.

In this way, since the contact member and the restricting member are disposed on opposite sides of the holding member in the width direction, the overlap between the contact member and the switching member in the width direction is large, making it easier for the contact member to transmit the force pressing the switching member to the switching member. This allows the contact member to more smoothly change the switching member between the first position and the second position.

The device also includes a switchback roller supported on the holding member for forward and reverse rotation, a roller gear supported integrally and rotatably on the switchback roller, and a drive gear rotatably supported on the housing and meshing with the roller gear to transmit a driving force in a forward direction and a driving force in a reverse direction to the roller gear, the center of rotation of the drive gear being located on a second line perpendicular to a first line connecting the rotation center of the holding member and the rotation center of the roller gear.

This makes it easy to apply a force to the roller gear that rotates the retaining member toward the closed position both when the drive gear transmits a driving force in the forward direction to the roller gear and when it transmits a driving force in the reverse direction.

According to the present invention, when the holding member is rotated to the open position, it is possible to prevent the switching member from interfering with the paper in the paper discharge path.

FIG. 2 is a central cross-sectional view showing the image forming apparatus. 11 is a side cross-sectional view showing the conveying section with the holding member in a closed position. FIG. 11 is a side cross-sectional view showing the conveying section when the holding member is in an open position. FIG. FIG. 13 is a side cross-sectional view showing the conveying section when the holding member is in the open position, illustrating the contact member and the electromagnetic solenoid provided on the right end side of the holding member. 13 is a perspective view of a holding member having a contact member and an electromagnetic solenoid provided on a right end side thereof, as viewed from the right rear side. FIG. FIG. FIG. 4 is a side cross-sectional view showing the switching member in a first position. FIG. 11 is a side cross-sectional view showing the switching member in a second position. FIG. 11 is a side cross-sectional view showing the switching member in a third position. 2 is a block diagram showing an electromagnetic solenoid, a seat sensor, and a drive motor connected to a control unit. FIG. 13 is a perspective view of a holding member having a restricting member provided on its left end side, as viewed from the left rear side. FIG. FIG. 4 is a side view showing a holding member and a restricting member. FIG. 4 is a side view showing a drive mechanism of the switchback roller. 4 is a side view showing a drive gear and a roller gear in a drive mechanism of the switchback roller. FIG. 1A is a side view showing a load F1 from the drive gear acting on the roller gear when the drive gear transmits a driving force in a forward direction to the roller gear, and FIG. 1B is a side view showing a load F2 from the drive gear acting on the roller gear when the drive gear transmits a driving force in a reverse direction to the roller gear. FIG. 13 is a plan view showing a stopper for holding the holding member in a closed position.

Next, the embodiment of the present invention will be described with reference to the attached drawings.

[Overall configuration of image forming device]
The image forming apparatus 1 shown in Fig. 1 is one embodiment of the image forming apparatus according to the present invention, and is configured as a color laser printer that forms an image on paper S by superimposing developer images of multiple colors using an electrophotographic method. However, the image forming apparatus 1 can also be configured as a monochrome laser printer that forms an image on paper using a single-color developer image. In this embodiment, the image forming apparatus 1 is configured as a laser-type image forming apparatus, but is not limited to this. In other words, the image forming apparatus 1 may be applied to other image forming methods, such as LED printers, inkjet printers, and thermal printers.

In the following description, the "left side," "right side," "rear side of the page," and "near side of the page" in FIG. 1 are defined as the "front side," "rear side," "left side," and "right side," respectively, of the image forming device 1. Additionally, the "upper side" and "lower side" in FIG. 1 are defined as the "upper side" and "lower side," respectively, of the image forming device 1.

The image forming device 1 comprises a housing 2, a paper feed unit 3 that supplies paper S, an image forming unit 5 that forms an image on the transported paper S, and a transport unit 7 that transports the paper S transported from the image forming unit 5. The housing 2 is a box formed in a substantially rectangular parallelepiped shape, and houses the paper feed unit 3, the image forming unit 5, and the transport unit 7. The housing 2 comprises a first opening 2A that opens to the rear surface, and a rear cover 21 that can be opened and closed relative to the first opening 2A.

The rear cover 21 has a pivot axis 21a extending in the left-right direction at its lower end, and is configured to be openable and closable by rotating relative to the housing 2 around the pivot axis 21a. The left-right direction in this embodiment is an example of a width direction perpendicular to the paper transport direction. The first opening 2A is open when the rear cover 21 is open, and is closed when the rear cover 21 is closed.

The upper part of the housing 2 is covered by a top cover 23. The top cover 23 is formed with a paper output tray 23a that is recessed so as to slope downward from the front side to the rear side. Paper S transported from the image forming unit 5 is output to the paper output tray 23a.

The paper feed unit 3 includes a sheet cassette 31, a first paper feed roller 32, a separation roller 33, a separation pad 33a, a first conveying roller pair 34, and a registration roller pair 35. Within the housing 2, a main body conveying path P1 for paper S is configured, which passes from the sheet cassette 31 through the image forming unit 5.

The sheet cassette 31 supports multiple sheets of paper S in a stacked state. The sheets S supported by the sheet cassette 31 are sent one by one to the transport path P1 by the first paper feed roller 32, the separation roller 33, and the separation pad 33a. The sheets S sent to the transport path P1 are transported toward the image forming unit 5 by the transport roller pair 34 and the registration roller pair 35.

The housing 2 also has a second opening 2B that opens to the front, and a front cover 29 that can be opened and closed relative to the second opening 2B. The front cover 29 has a rotation axis 29a that extends in the left-right direction at its lower end, and is configured to be openable and closable by rotating relative to the housing 2 around the rotation axis 29a. The second opening 2B is open when the front cover 29 is open, and is closed when the front cover 29 is closed.

The paper feed unit 3 includes a second paper feed roller 38 and a second conveying roller pair 39. When the front cover 29 is open, the paper S placed on the front cover 29 is sent out by the second paper feed roller 38 moving downward, conveyed by the second conveying roller pair 39, and merged with the conveying path P1. The paper S that has merged with the conveying path P1 is conveyed toward the image forming unit 5 by the registration rollers 35.

The image forming unit 5 is disposed above the paper feed unit 3 and includes four drum units 51 arranged side by side in the front-to-rear direction. Each drum unit 51 corresponds to one of the colors: black, yellow, magenta, and cyan. Each drum unit 51 includes a photosensitive drum 51a, a charger 51b, and a developing roller 51c.

The image forming section 5 also includes a scanner unit 52 and a fixing unit 60. The scanner unit 52 is provided at the top of the housing 2, and laser light based on image data is irradiated at high speed onto the surface of the photosensitive drum 51 corresponding to each color through a polygon mirror, a lens, a reflecting mirror, etc. The fixing unit 60 is disposed further downstream than the photosensitive drum 51a on the most downstream side in the transport direction of the paper S.

A transfer belt 40 is disposed below the image forming unit 5 across the transport path P1. The transfer belt 40 is stretched between a drive roller 41a and a driven roller 41b disposed in front of the drive roller 41a. A transfer roller 42 is disposed at a position facing each of the photosensitive drums 51a across the transfer belt 40.

In the image forming unit 5, the photosensitive drums 51a, which are uniformly charged by the chargers 51b, are selectively exposed to light by the scanner units 52. This exposure selectively removes charge from the surfaces of the photosensitive drums 51a, and an electrostatic latent image is formed on the surfaces of the photosensitive drums 51a.

A developing bias is applied to the developing roller 51c, and when the electrostatic latent image formed on the photosensitive drum 51a faces the developing roller 51c, the potential difference between the electrostatic latent image and the developing roller 51c causes toner to be supplied from the developing roller 51c to the electrostatic latent image. This forms a toner image on the surface of the photosensitive drum 51a.

When the paper S is conveyed toward the image forming unit 5 and is conveyed onto the transfer belt 40, it is conveyed by the transfer belt 40 and passes between the transfer belt 40 and each photosensitive drum 51a in sequence. Then, when the toner image on the surface of the photosensitive drum 51a faces the paper S, it is transferred onto the paper S by the transfer bias applied to the transfer roller 42.

The paper S onto which the toner image has been transferred is transported to the fixing unit 60. The fixing unit 60 is equipped with a heating roller 61 that heats the paper S, and a pressure roller 62 that is arranged opposite the heating roller 61. The paper S transported to the fixing unit 60 passes between the heating roller 61 and the pressure roller 62, which are pressed against each other, thereby thermally fixing the toner image.

The paper S with the toner image thermally fixed thereon is transported downstream of the image forming unit 5 by the transport unit 7. The transport unit 7 has a first transport unit 71 and a second transport unit 72. The first transport unit 71 has a paper discharge function that discharges the paper S transported from the image forming unit 5 to the paper discharge tray 23a. The second transport unit 72 has a re-transport function that transports the paper S transported from the image forming unit 5 back to the image forming unit 5.

In this embodiment, the second transport unit 72 has a re-transport function, but is not limited thereto. The second transport unit 72 may also have a function of transporting the paper S transported from the image forming unit 5 toward an optional device mounted on the top of the image forming device 1. An example of an optional device that can be mounted on the image forming device 1 is a mailbox with multiple sheet trays.

In the image forming device 1, when an image is formed on both sides of the paper S, the paper S, which has an image formed on one side by the image forming section 5 and is discharged from the fixing unit 60, is inverted by the second conveying section 72 and conveyed again to the image forming section 5, and an image is formed on the other side by the image forming section 5, and then discharged to the paper output tray 23a by the first conveying section 71. In this case, since the image forming device 1 has a second conveying section 72 dedicated to inverting the paper S and conveying it again to the image forming section 5, it is possible to increase the number of sheets of paper conveyed per unit time during double-sided printing compared to an image forming device that inverts the paper S only by the first conveying section 71. Note that, depending on the printing mode, the paper S can also be inverted only by the first conveying section 71, in which case the paper S is inverted without using the second conveying section 72 and conveyed again to the image forming section 5.

[Transport section]
As shown in FIGS. 1 to 4, the conveying unit 7 includes a first conveying unit 71, a second conveying unit 72, a switching member 73, a holding member 25, and a sheet sensor 92.

The first transport section 71 has an intermediate discharge roller pair 711 that is disposed downstream of the fixing unit 60 in the paper transport direction and transports the paper S, and a discharge roller pair 712 that is disposed downstream of the intermediate discharge roller pair 711 and transports the paper S and discharges it to the discharge tray 23a. The intermediate discharge roller pair 711 and the discharge roller pair 712 are supported by the housing 2.

The first transport section 71 has a discharge path P2 along which the paper S is guided from the fixing unit 60 to the discharge tray 23a. The discharge path P2 is a path that guides the paper S transported from the image forming section 5 to the discharge tray 23a.

The discharge path P2 extends from the fixing unit 60 diagonally upward toward the rear, then extends upward to reach the intermediate discharge roller pair 711, and then extends diagonally upward toward the front toward the discharge tray 23a. The intermediate discharge roller pair 711 is disposed midway along the discharge path P2, and the discharge roller pair 712 is disposed at the downstream end of the discharge path P2.

In the image forming device 1, when the paper S transported from the image forming section 5 is discharged to the discharge tray 23a, the paper S on which the toner image has been thermally fixed by the fixing unit 60 is transported along the discharge path P2 by the intermediate discharge roller pair 711, and then discharged to the discharge tray 23a by the discharge roller pair 712.

The second transport section 72 has a re-transport path P3 that branches off from the first transport path P2 and transports the paper S transported from the image forming section 5 back to the image forming section 5. The re-transport path P3 branches off from the paper discharge path P2 at a branching position Ps. The branching position Ps is located downstream of the fixing unit 60 and upstream of the paper discharge roller pair 712 in the paper transport direction.

The re-conveying path P3 extends diagonally upward and rearward from the branching position Ps, and has a first path P31 for transporting the paper S transported from the image forming unit 5, and a second path P32 that branches off from the first path P31 and extends downward to transport the inverted paper again toward the image forming unit 5. The first path P31 extends to the upper end of the housing 2. The second path P32 branches off from the first path P31 and extends downward, and then extends forward to reach the first transport roller 34.

The second conveying section 72 has a switchback roller 721 and a pinch roller 722 arranged on the first path P31 of the re-conveying path P3. The switchback roller 721 is configured to be drivable in the forward and reverse rotation directions, and the pinch roller 722 is configured to abut against the switchback roller 721 and rotate in response to the rotation.

When the switchback roller 721 rotates in the forward direction, the paper S sandwiched between the pinch roller 722 and the switchback roller 721 is transported in a direction in which the paper S is discharged from the housing 2. When the switchback roller 721 rotates in the reverse direction, the paper S sandwiched between the pinch roller 722 and the switchback roller 721 is transported in a direction in which the paper S is pulled into the housing 2. Therefore, below the switchback roller 721, the second path P32 branches off from the first path P31.

The holding member 25 is disposed in front of the rear cover 21. The holding member 25 has a rotation axis 25a at its lower end that is parallel to the rotation axis 21a, and is supported by the housing 2 so as to be rotatable about the rotation axis 25a.

The holding member 25 is configured to be rotatable between a closed position (position shown in FIG. 2) that forms at least a part of the paper discharge path P2, and an open position (position shown in FIG. 3) that opens the paper discharge path P2. The holding member 25 can be rotated to the open position when the rear cover 21 is in an open state. The holding member 25 supports a switchback roller 721 and a pinch roller 722. The switchback roller 721 is supported by the holding member 25 so that it can rotate forward and backward.

The pivot axis 25a of the holding member 25 is disposed above the pivot axis 21a of the rear cover 21, and is configured so that when the rear cover 21 and the holding member 25 are opened, the holding member 25 is positioned above the rear cover 21.

The switching member 73 is arranged so as to be located near the branching position Ps between the discharge path P2 and the re-conveying path P3 when the rear cover 21 is closed. The switching member 73 has a rotation axis 73a parallel to the rotation axis 21a at its upper end in a side view, and a tip portion 73b at its lower end, which is the end opposite the rotation axis 73a. The tip portion 73b is an example of the rotation tip of the switching member.

The switching member 73 is held by the holding member 25 so as to be rotatable around a rotation axis 73a. The rotation axis 73a is an example of a rotation center of the switching member. The rotation axis 73a is located above the branch position Ps. The rotation axis 73a is also located above and rearward of the rotation axis 25a of the holding member 25. The tip 73b of the switching member 73 and the rotation axis 73a are located on opposite sides of the rotation axis 25a of the holding member 25. The switching member 73 has a front guide surface 73A and a rear guide surface 73B.

When the holding member 25 is in the closed position, the switching member 73 rotates about the rotation axis 73a, so that its relative position with respect to the holding member 25 can be changed between a first position (the position of the switching member 73-1 shown by the solid line in FIG. 2) in which the paper S that has passed between the heating roller 61 and the pressure roller 62 of the fixing unit 60 of the image forming unit 5 is guided to the paper discharge path P2, and a second position (the position of the switching member 73-2 shown by the two-dot chain line in FIG. 2) in which the paper S transported from the image forming unit 5 is guided to the first path P31 of the re-transport path P3.

When the switching member 73 is in the first position, it opens the paper discharge path P2 and blocks the first path P31 of the re-conveyance path P3. When the switching member 73 is in the second position, it blocks the paper discharge path P2 and opens the first path P31 of the re-conveyance path P3. The tip 73b when the switching member 73 moves to the second position is located higher than the tip 73b when the switching member 73 moves to the first position.

When the holding member 25 is in the open position, the switching member 73 changes its relative position with respect to the holding member 25 to a third position (the position of the switching member 73-3 shown in FIG. 3) that is different from the first and second positions. Here, the third position is a position in which the switching member 73 does not interfere with the paper S in the paper discharge path P2. Also, as the holding member 25 rotates from the closed position to the open position, the switching member 73 changes its relative position with respect to the holding member 25 from the first or second position to the third position.

The first transport section 71 includes a guide member 27 supported by the housing 2. The guide member 27 has a first guide surface 271 that constitutes part of the paper discharge path P2. The holding member 25 and the switching member 73 are located behind the guide member 27 and face the first guide surface 271 of the guide member 27.

The holding member 25 has a second guide surface 251 and a third guide surface 252. The second guide surface 251 constitutes a part of the paper discharge path P2. The third guide surface 252 is located rearward of the second guide surface 251 and constitutes a part of the re-conveying path P3 in the second conveying section 72. The rear cover 21 has a fourth guide surface 211 located rearward of the third guide surface 252 and constitutes a part of the re-conveying path P3. When the switching member 73 is in the first position, the first guide surface 271, the second guide surface 251, and the front guide surface 73A guide the paper S passing through the paper discharge path P2, and when the switching member 73 is in the second position, the third guide surface 252, the fourth guide surface 211, and the rear guide surface 73B guide the paper S passing through the re-conveying path P3.

The holding member 25 is configured to form part of the discharge path P2 in the first transport section 71 when rotated to the closed position, and to open the discharge path P2 when rotated to the open position. The holding member 25 can be rotated from the closed position to the open position when the rear cover 21 is open, and if a jam of paper S occurs in the discharge path P2, the holding member 25 can be rotated to the open position to open the discharge path P2 and easily clear the jam of paper S.

The rotation axis 73a of the switching member 73 moves along the rotation direction of the holding member 25 as the holding member 25 rotates around the rotation axis 25a. For example, when the holding member 25 rotates from the closed position toward the open position, the rotation axis 73a moves in a direction away from the guide member 27, and when the holding member 25 rotates from the open position toward the closed position, the rotation axis 73a moves in a direction toward the guide member 27.

The sheet sensor 92 is a sensor that detects the paper S transported along the paper discharge path P2, and is positioned between the fixing unit 60 and the branch point Ps in the paper transport direction.

[Switching member drive unit]
As shown in FIGS. 4 to 6, the switching member 73 has an operating lever 73c at the right end in the left-right direction, which extends from the rotation axis 73a to the side opposite to the tip end 73b.

The switching member 73 has a first flapper portion 731 arranged in the center in the width direction perpendicular to the transport direction of the paper S, and a second flapper portion 732 arranged closer to the end in the width direction than the first flapper portion 731. A plurality of second flapper portions 732 are arranged side by side on both the left and right sides of the first flapper portion 731. The first flapper portion 731 and the second flapper portion 732, and the second flapper portion 732 and the second flapper portion 732, which are adjacent in the width direction, are each connected by a connection portion 733.

When viewed in the axial direction of the pivot axis 73a, the length from the pivot axis 73a to the tip 732b of the second flapper portion 732 is shorter than the length from the pivot axis 73a to the tip 731b of the first flapper portion 731.

The image forming device 1 includes an abutment member 75 that abuts against the switching member 73 when the holding member 25 is in the closed position, thereby changing the switching member 73 between the first position and the second position, and an electromagnetic solenoid 74 that drives the abutment member 75. The electromagnetic solenoid 74 and the abutment member 75 are located on the right end side of the holding member 25 in the width direction perpendicular to the paper transport direction, and are supported by the housing 2.

The abutment member 75 can swing around a swing shaft 75a at its lower end, and has an abutment portion 75b at its upper end that can abut against the operating lever 73c of the switching member 73. The abutment portion 75b of the abutment member 75 and the operating lever 73c of the switching member 73 overlap in the width direction and are configured to be able to abut against each other. The abutment member 75 can be displaced between a first operating position that changes the switching member 73 to a first position as shown in FIG. 6(a) and a second operating position that changes the switching member 73 to a second position as shown in FIG. 6(b).

The electromagnetic solenoid 74 has an expandable plunger 74a, which is connected to an abutment member 75. The electromagnetic solenoid 74 can be switched between an excited state and a non-excited state, and is configured so that the plunger 74a expands when in the non-excited state and contracts when in the excited state. The abutment member 75 is displaced to a first operating position when the plunger 74a of the electromagnetic solenoid 74 expands, and is displaced to a second operating position when the plunger 74a contracts.

As shown in FIG. 7, when the holding member 25 is in the closed position, the electromagnetic solenoid 74 is in a non-excited state, and the abutting member 75 is displaced to the first operating position, the abutting portion 75b of the abutting member 75 abuts against the operating lever 73c of the switching member 73, and the switching member 73 changes to the first posture. In this case, the first straight line L1 connecting the rotation axis 25a of the holding member 25 and the rotation center 721a of the switchback roller 721 and the third straight line L3 connecting the rotation axis 73a of the switching member 73 and the tip 73b form a first angle θ1. The first angle θ1 is the angle formed by the first straight line L1 and the third straight line L3 on the rear side of the first straight line L1 and the third straight line L3.

On the other hand, as shown in FIG. 8, when the holding member 25 is in the closed position and the electromagnetic solenoid 74 is in an excited state and the abutting member 75 is displaced to the second operating position, the abutting portion 75b of the abutting member 75 abuts against the operating lever 73c of the switching member 73, and the switching member 73 changes to the second posture. In this case, the first line L1 and the third line L3 form a second angle θ2 that is larger than the first angle θ1. The second angle θ2 is the angle formed by the first line L1 and the third line L3 on the same side as the first angle θ1.

In addition, when the electromagnetic solenoid 74 is switched from a state in which the electromagnetic solenoid 74 is in a non-excited state and the switching member 73 is changed to the first position to an excited state, the abutment member 75, which has been displaced to the first operating position, displaces to the second operating position, and presses the operating lever 73c of the switching member 73, which is in the first position, thereby changing it to the second position.

Conversely, when the electromagnetic solenoid 74 is switched from an excited state with the switching member 73 changed to the second position to a non-excited state, the abutment member 75, which had been displaced to the second operating position, displaces to the first operating position, and the abutment portion 75b of the abutment member 75 moves in a direction away from the operating lever 73c of the switching member 73, so that the switching member 73 changes from the second position to the first position due to its own weight.

As shown in FIG. 9, when the holding member 25 is in the open position, the rotation axis 73a of the switching member 73 moves in a direction away from the guide member 27 compared to when the holding member 25 is in the closed position, and the switching member 73 is spaced apart from the abutment member 75. In this way, when the holding member 25 is in the open position and the switching member 73 is spaced apart from the abutment member 75, the switching member 73 changes to the third position due to its own weight.

When the switching member 73 is in the third position, the first line L1 and the third line L3 form a third angle θ3 smaller than the first angle θ1 and the second angle θ2. The third angle θ3 is an angle formed by the first line L1 and the third line L3 on the same side as the first angle θ1 and the second angle θ2. When the switching member 73 is in the third position, the first line L1 and the third line L3 form the third angle θ3, so that the tip 73b of the switching member 73 is lowered downward compared to when the angle is larger than the third angle θ3, and it is possible to suppress interference of the switching member 73 with the paper S in the paper discharge path P2. In other words, when the holding member 25 is in the open position, the switching member 73 can move away from the first guide surface 271 and away from the paper discharge path P2 by taking the third position, rather than when the switching member 73 remains in the first position or the second position. At this time, the tip 73b of the switching member 73 in the third position is located farther away from the tip 73b of the switching member 73 in the second position than the tip 73b of the switching member 73 in the first position.

Furthermore, when the holding member 25 rotates from the closed position to the open position, the switching member 73 moves away from the abutting member 75, and the pressing force from the abutting member 75 no longer acts on the switching member 73, so that the switching member 73 in the first or second position rotates under its own weight in a direction that reduces the angle between the first line L1 and the third line L3, changing to the third position. In this way, as the holding member 25 rotates from the closed position to the open position, the relative position of the switching member 73 with respect to the holding member 25 changes to the third position, making it possible to prevent the switching member 73 from interfering with the paper S in the paper discharge path P2 when the holding member 25 rotates to the open position.

In addition, when the holding member 25 is rotated to the open position, the switching member 73 moves away from the abutting member 75, and the switching member 73 can change to the third position by its own weight regardless of the state of the abutting member 75, such as whether the abutting member 75 is in the first operating position or the second operating position. Furthermore, once the switching member 73 has changed to the third position, it can maintain the third position regardless of the state of the abutting member 75.

In addition, the rotation axis 73a of the switching member 73 moves in a direction away from the guide member 27 as the holding member 25 rotates from the closed position to the open position, so that when the holding member 25 rotates to the open position, the switching member 73 moves as a whole in a direction away from the guide member 27. This makes it easy for the switching member 73 to change to the third position in which it does not interfere with the paper S in the paper discharge path P2.

The tip 73b of the switching member 73 and the pivot axis 73a are located on opposite sides of the pivot axis 25a of the holding member 25. Even in this case, by changing the switching member 73 to the third position, it is possible to prevent the switching member 73 from interfering with the paper in the paper discharge path P2 when the holding member 25 is rotated to the open position.

Furthermore, since the abutment member 75 is supported by the housing 2 and does not move even when the holding member 25 rotates, it is possible to easily separate the switching member 73 and the abutment member 75 when the holding member 25 rotates to the open position.

[Control unit]
10, the image forming apparatus 1 includes a control unit 9 that controls switching between an excited state and a non-excited state of the electromagnetic solenoid 74. The control unit 9 can control the operation of the contact member 75 by controlling the switching between an excited state and a non-excited state of the electromagnetic solenoid 74. In other words, the control unit 9 can control the displacement of the contact member 75 to a first operating position and a second operating position. The electromagnetic solenoid 74 and a sheet sensor 92 are connected to the control unit 9.

The control unit 9 is configured to displace the contact member 75 to the first operating position when it is determined that the holding member 25 needs to be rotated to the open position. Here, the case where the holding member 25 needs to be rotated to the open position is, for example, when a jam occurs in the paper S transported along the paper discharge path P2, and it is necessary to rotate the holding member 25 to the open position to open the paper discharge path P2 and remove the jammed paper from the paper discharge path P2. Note that the control unit 9 can determine that a jam has occurred in the paper discharge path P2 when, for example, the detection of the paper S by the sheet sensor 92 downstream of the fixing unit 60 continues for a predetermined period of time or more.

When the holding member 25 is rotated to the open position to open the paper discharge path P2, the switching member 73 and the abutting member 75 are separated, but when the holding member 25 is returned from the open position to the closed position, the switching member 73 and the abutting member 75 abut. In this case, the degree of pressure applied to the switching member 73 by the abutting member 75 is smaller when the abutting member 75 is displaced to the first operating position than when the abutting member 75 is displaced to the second operating position.

Therefore, when the control unit 9 determines that it is necessary to rotate the holding member 25 to the open position, the contact member 75 is displaced to the first operating position, so that when the holding member 25, which has been rotated to the open position, returns to the closed position, the amount of pressure applied to the switching member 73 by the contact member 75 is reduced, making it easier for the switching member 73 to be positioned in an appropriate position.

[Regulation member]
11 and 12, the image forming apparatus 1 includes a regulating member 26 that applies a sliding resistance to the holding member 25 to regulate the rotational movement of the holding member 25 when the holding member 25 rotates between the closed position and the open position. The regulating member 26 is provided between the housing 2 and the holding member 25, and is located on the left end side of the holding member 25 in the width direction perpendicular to the paper transport direction.

The holding member 25 has an engagement protrusion 253 that protrudes leftward from the left end surface of the holding member 25. The restricting member 26 has a rotation support portion 261 and an engagement hole portion 262. The housing 2 has a support shaft 28 that extends in the left-right direction, and the rotation support portion 261 is supported by the support shaft 28 so as to be rotatable. The engagement hole portion 262 has a first end portion 262a, a second end portion 262b, and a pair of long side portions 262c.

The first end 262a and the second end 262b are formed in an arc shape. The first end 262a and the second end 262b are arranged apart from each other, and the first end 262a is located closer to the rotation support part 261 than the second end 262b. The first end 262a is connected to the rotation support part 261.

The pair of long sides 262c connect the first end 262a and the second end 262b, and the first end 262a, the second end 262b, and the pair of long sides 262c form a long hole that is long in the direction of separation between the first end 262a and the second end 262b. The engagement protrusion 253 is slidably engaged with the engagement hole 262, and when the holding member 25 is in the closed position, the engagement protrusion 253 is located on the first end 262a side of the engagement hole 262.

The pair of long side portions 262c extend in the direction separating the first end portion 262a and the second end portion 262b, and the intermediate portions in the extending direction are curved in a direction approaching each other more than the two end portions. The long side portions 262c are elastic, and the intermediate portions in the extending direction of the pair of long side portions 262c are spaced apart from each other by a distance smaller than the outer diameter of the engagement protrusion 253.

When the holding member 25 in the closed position rotates toward the open position, the engagement protrusion 253 slides within the engagement hole 262 toward the second end 262b. In this case, the engagement protrusion 253 moves while sliding against the inner surface of the long side portion 262c, so a sliding resistance is applied to the engagement protrusion 253. In this way, when the holding member 25 rotates toward the open position, a sliding resistance is applied to the engagement protrusion 253 of the holding member 25 by the regulating member 26, so the rotational movement of the holding member 25 is regulated, and it is possible to prevent the holding member 25 from rotating suddenly toward the open position.

Here, when the restricting member 26 is provided between the left end of the holding member 25 and the housing 2, a force acts on the holding member 25 to move the holding member 25 in the width direction toward the side where the holding member 25 and the housing 2 move apart. In this case, when the restricting member 26 and the abutting member 75 are arranged on the same side in the width direction, the force acting on the holding member 25 acts in a direction that reduces the overlap in the width direction between the abutting portion 75b of the abutting member 75 and the operating lever 73c of the switching member 73. Conversely, when the restricting member 26 and the abutting member 75 are arranged on opposite sides in the width direction, the force acts in a direction that increases the overlap in the width direction between the abutting portion 75b of the abutting member 75 and the operating lever 73c of the switching member.

In the image forming device 1, the abutment member 75 is disposed on the right end side of the holding member 25, and the regulating member 26 is disposed on the left end side of the holding member 25, so that the abutment member 75 and the regulating member 26 are disposed on opposite sides of the holding member 25 in the width direction.

As a result, the overlap in the width direction between the abutment portion 75b of the abutment member 75 and the operating lever 73c of the switching member 73 becomes larger, making it easier for the abutment portion 75b to transmit the force pressing the operating lever 73c to the operating lever 73c. This makes it possible for the abutment member 75 to more smoothly change the switching member 73 between the first position and the second position.

In this embodiment, the abutment member 75 is disposed on the right end side in the width direction of the holding member 25, and the regulating member 26 is disposed on the left end side in the width direction of the holding member 25, but the abutment member 75 can also be disposed on the left end side in the width direction of the holding member 25, and the regulating member 26 can be disposed on the right end side in the width direction of the holding member 25.

[Switchback roller drive mechanism]
13 and 14 , the image forming apparatus 1 includes a drive mechanism 10 for driving the switchback roller 721. The drive mechanism 10 for the switchback roller 721 includes a roller gear 127, a drive gear 126, a drive motor 95, and a drive force transmission path 11.

The roller gear 127 is supported rotatably integrally with the switchback roller 721. The roller gear 127 and the switchback roller 721 are arranged coaxially, and the center of rotation 127a of the roller gear 127 coincides with the center of rotation 721a of the switchback roller 721. The drive gear 126 is supported rotatably on the housing 2, and meshes with the roller gear 127 to transmit driving forces in the forward and reverse directions to the roller gear 127.

The drive motor 95 is a drive source capable of outputting drive force in the forward and reverse rotation directions. As shown in FIG. 10, the drive motor 95 is connected to the control unit 9, and the control unit 9 can control the operation of the drive motor 95. The drive force transmission path 11 is configured to be capable of transmitting the drive force from the drive motor 95 to the drive gear 126.

The driving force transmission path 11 has a pulley 111 attached to the driving motor 95, a pulley 112 arranged above the pulley 111, and a belt 113 stretched around the pulleys 111 and 112. The driving force transmission path 11 also has a pulley 121 fixed to the pulley 112 so as to be integrally rotatable, a pulley 122 arranged above the pulley 121 and fixed to the driving gear 126 so as to be integrally rotatable, a pulley 123 arranged between the pulleys 121 and 122, and a belt 124 stretched around the pulleys 121, 122, and 123.

The driving force from the drive motor 95 is transmitted to the drive gear 126 via the belts 113 and 124. When the driving force is transmitted to the drive gear 126, the drive gear 126 rotates in the forward or reverse direction. When the drive gear 126 rotates, the driving force in the forward or reverse direction is transmitted to the roller gear 127 that meshes with the drive gear 126. This causes the switchback roller 721 to rotate in the forward or reverse direction.

As shown in FIG. 14, the drive gear 126 is arranged so that the rotation center 126a of the drive gear 126 is located on a second straight line L2 that is perpendicular to a first straight line L1 that connects the rotation axis 25a of the holding member 25 and the rotation center 127a of the roller gear 127. Note that since the rotation center 127a of the roller gear 127 and the rotation center 721a of the switchback roller 721 coincide with each other, the straight line that connects the rotation axis 25a of the holding member 25 and the rotation center 127a of the roller gear 127, and the straight line that connects the rotation axis 25a of the holding member 25 and the rotation center 721a of the switchback roller 721 are both the first straight line L1.

As shown in FIG. 15(a), when the drive gear 126 transmits a driving force in the forward direction to the roller gear 127, that is, when the switchback roller 721 is driven in a direction in which it rotates in the forward direction, a load F1 from the drive gear 126 acts on the roller gear 127. The load F1 is a force directed diagonally downward and rearward.

The load F1 can be broken down into an X-direction component F1x and a Y-direction component F1y. In this case, the X-direction is the direction along the meshing surface of the teeth of the roller gear 127 with the drive gear 126, and the Y-direction is the direction perpendicular to the meshing surface of the teeth of the roller gear 127 with the drive gear 126. The angle θf1 between the Y-direction component F1y of the load F1 and the second straight line L2 is less than 90°. In other words, the Y-direction component F1y is inclined toward the side approaching the drive gear 126 in the direction along the second straight line L2, and acts as a force that draws the holding member 25 from the open position side toward the closed position side.

On the other hand, as shown in FIG. 15(b), when the drive gear 126 transmits a driving force in the reverse direction to the roller gear 127, that is, when the switchback roller 721 is driven in a direction that rotates in the reverse direction, a load F2 from the drive gear 126 acts on the roller gear 127. The load F2 is a force that acts diagonally upward and rearward.

The load F2 can be broken down into an X-direction component F2x and a Y-direction component F2y. The X-direction and Y-direction in this case are the same as those in the case of the load F1. The angle θf2 between the Y-direction component F2y of the load F2 and the second line L2 is less than 90°. In other words, the Y-direction component F2y is inclined toward the drive gear 126 in the direction along the second line L2, and acts as a force that draws the holding member 25 from the open position side toward the closed position side.

As shown in FIG. 16, the portions of the housing 2 facing the left and right ends of the holding member 25 have inclined surfaces 24 that incline outwardly to the left and right as they move from the rear to the front. Note that FIG. 16 only shows the portion on the left end side of the holding member 25.

As shown in Figures 14 to 16, stoppers 254 are provided on the left, right and top ends of the holding member 25. The stoppers 254 have a support portion 254a that is rotatably supported on the holding member 25, and an engagement portion 254b that can engage with the inclined surface 24. A spring 255 is provided between the holding member 25 and the stoppers 254, and the stoppers 254 are biased by the spring 255 in a direction in which the engagement portion 254b is pressed against the inclined surface 24.

When the engagement portion 254 is pressed against the inclined surface 24 by the spring 255, a force acts on the holding member 25 in a direction that moves the upper end of the holding member 25 forward. In other words, when the stopper 254 engages with the inclined surface 24 of the housing 2, a force acts on the holding member 25 in a direction that pulls it from the open position side toward the closed position side, and this force holds the holding member 25 in the closed position.

Here, when the drive gear 126 is driven, if the angles θf1, θf2 between the Y-direction components F1y, F2y of the loads F1, F2 acting on the roller gear 127 and the second straight line L2 exceed 90°, a force acts on the holding member 25 via the roller gear 127 in a direction pushing the holding member 25 from the closed position side toward the open position side.

In this way, when a force acts on the holding member 25 in a direction pushing it towards the open position, the holding member 25 may rotate towards the open position against the force of the stopper 254 towards the closed position. When the holding member 25 rotates towards the open position, the meshing between the drive gear 126 and the roller gear 127 becomes shallow, which may result in the drive force not being transmitted smoothly from the drive gear 126 to the roller gear 127, which is undesirable.

However, in this embodiment, the Y-direction components F1y and F2y of the loads F1 and F2 are both less than 90°, and a force acts on the holding member 25 in a direction pulling it toward the closed position both when the drive gear 126 is driven in the forward direction and when it is driven in the reverse direction. As a result, when the drive gear 126 is driven, the meshing between the drive gear 126 and the roller gear 127 becomes deeper, and the drive force is transmitted smoothly from the drive gear 126 to the roller gear 127.

In addition, in the image forming device 1, the rotation center 126a of the drive gear 126 is on the second line L2 that is perpendicular to the first line L1, so the direction in which the load F1 acts and the direction in which the load F2 acts are symmetrical across the second line L2.

Therefore, the force acting on the roller gear 127 in the rotation direction of the holding member 25 can be made uniform when the drive gear 126 transmits a driving force in the forward direction to the roller gear 127 and when it transmits a driving force in the reverse direction. In addition, the angle θf1 at the Y-direction component F1y of the load F1 and the angle θf2 at the Y-direction component F2y of the load F2 are not larger than each other, and the angles θf1 and θf2 can be made the same.

As a result, when the drive gear 126 transmits a driving force in the forward direction to the roller gear 127 and when it transmits a driving force in the reverse direction, the angles θf1 and θf2 are less than 90°, making it easy to apply a force to the roller gear 127 in a direction that rotates the holding member 25 toward the closed position.

In this embodiment, the posture of the switching member 73 is specified by the angle formed by the first straight line L1 connecting the rotation axis 25a of the holding member 25 and the rotation center 721a of the switchback roller 721 and the third straight line L3 connecting the rotation axis 73a of the switching member 73 and the tip 73b, but this is not limited to this. For example, the first posture, the second posture, and the second posture may be specified by the angle formed by the third guide surface 252 of the holding member 25 and the front guide surface 73A of the switching member 73. In addition, the first posture, the second posture, and the second posture may be specified by the distance between the tip 73b of the switching member 73 and the third guide surface 252 of the holding member 25, rather than the front guide surface 73A. In other words, the relative posture of the switching member 73 with respect to the holding member 25 can be specified based on the positional relationship such as the angle and distance between the specific position of the holding member 25 and the specific position of the switching member 73.

In addition, in this embodiment, the switching member 73 is configured to change to the third position by its own weight, but this is not limited to this. For example, the switching member 73 may be configured to change to the third position by changing the position of the switching member 73 using another driving member or the like. Furthermore, the abutment member 75 may not be supported by the housing 2, but may be supported by the holding member 25.

REFERENCE SIGNS LIST 1 Image forming apparatus 2 Housing 5 Image forming section 7 Conveying section 9 Control section 23a Paper discharge tray 25 Holding member 25a Rotation axis 26 Regulating member 27 Guide member 71 First conveying section 72 Second conveying section 73 Switching member 73a Rotation axis 73b Tip 75 Contact member 126 Drive gear 126a Rotation center 127 Roller gear 127a Rotation center 721 Switchback roller L1 First straight line L2 Second straight line P2 Paper discharge path P3 Re-conveying path S Paper

Claims (5)

a housing having a paper output tray to which paper conveyed from an image forming unit is output;
a first conveying section having a paper discharge path that guides the paper conveyed from the image forming section to the paper discharge tray;
a second conveying section having a re-conveying path branching off from the paper discharge path;
a holding member supported by the housing so as to be rotatable between a closed position that forms at least a part of the paper discharge path and an open position that opens the paper discharge path;
a switching member that is rotatably held by the holding member, and whose posture relative to the holding member can be changed between a first posture for guiding the paper to the paper discharge path when the holding member is in the closed position and a second posture for guiding the paper to the re-conveying path;
a contact member that contacts the switching member when the holding member is in the closed position, thereby changing the switching member between the first position and the second position;
A control unit for controlling the operation of the contact member;
Equipped with
the holding member has a second guide surface that constitutes a part of the paper discharge path and a third guide surface that constitutes a part of the re-conveyance path,
the first transport section forms a part of the paper discharge path and has a first guide surface facing the second guide surface;
the third guide surface is located on the opposite side of the first guide surface across the second guide surface,
a rotation tip of the switching member in the first posture is farther from the first guide surface than a rotation tip of the switching member in the second posture,
When the holding member moves from the closed position to the open position, the second guide surface moves away from the first guide surface,
the abutment member is displaceable between a first operational position at which the switching member is changed to the first posture and a second operational position at which the switching member is pressed from the first posture to change to the second posture,
When the control unit determines that it is necessary to rotate the holding member to an open position, the control unit displaces the contact member to the first operating position,
the switching member changes its relative posture with respect to the holding member to a third posture as the holding member rotates from the closed position to the open position, and when the holding member rotates to the open position, the switching member moves away from the abutment member and changes to the third posture by its own weight;
an image forming apparatus characterized in that a rotational tip of the switching member in the third position is farther away from the rotational tip of the switching member in the second position than the rotational tip of the switching member in the first position, and the switching member in the third position does not interfere with paper in the paper discharge path. the first conveying portion has the first guide surface and a guide member facing the switching member,
The image forming apparatus according to claim 1 , wherein the rotation center of the switching member moves in a direction away from the guide member as the holding member rotates from the closed position to the open position. 3. The image forming apparatus according to claim 2 , wherein the rotation tip and the rotation center of the switching member are located on opposite sides of the rotation center of the holding member. The image forming apparatus according to any one of claims 1 to 3 , wherein the contact member is supported by the housing. a restricting member provided between the housing and the holding member, the restricting member applying a sliding resistance to the holding member to restrict a rotational movement of the holding member when the holding member rotates between the closed position and the open position,
the regulating member is located at one of one end side and the other end side in a width direction perpendicular to a paper conveying direction of the holding member,
The image forming apparatus according to claim 1 , wherein the contact member is located at the other of one end side and the other end side in the width direction of the holding member.

Images