JP2002148992A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device characterized by that although the opening/closing operation of an opening/closing cover is associated with the pressing and releasing between two rollers of a fixing device, the opening/ closing cover is less loaded by the association, made low-cost and placed in simple opening/closing operation with a small force. SOLUTION: The load of the energizing force of a spring 37 transmitted to a link member 39 which moves a pressure roller 27 to a press-contacting/ release position by pushing a direct-acting rod 38 through an operation rod 46 and swinging a roller support member 36 against the energizing force of the spring 37 is received by a support plate 40 engaged with the link member 39 and not transmitted to a connecting rod 41 which has one end coupled with a top cover 31 and the other end coupled with the support plate 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus having a mechanism for releasing the pressure contact between a heating roller and a pressure roller in a fixing device in conjunction with opening and closing of an opening and closing cover. .

[0002]

2. Description of the Related Art Generally, an image forming apparatus such as a laser printer is provided with a fixing device for fixing toner transferred to a sheet when passing between a photosensitive drum and a transfer roller.

[0003] Such a fixing device is usually provided downstream of the process cartridge in the paper transport direction, and includes a heating roller and a pressure roller for pressing the heating roller. And a pressure roller are arranged to face each other while being pressed against each other, and are configured to thermally fix the toner transferred onto the paper while the paper passes between the heating roller and the pressure roller. I have.

However, when a paper jam occurs between the heating roller and the pressure roller, the heating roller and the pressure roller are in pressure contact with each other. It is necessary to remove the paper, for example, for example, a mechanism having a mechanism for releasing the pressure contact between the heating roller and the pressure roller in conjunction with the opening operation of the opening and closing cover that is opened and closed with respect to the apparatus body, Various proposals have been made.

[0005]

However, a mechanism for linking the opening operation of the opening / closing cover and the release of the pressure contact between the heating roller and the pressing roller usually employs a cam member or a link member. However, in any case, the load generated at the time of pressing or releasing between the heating roller and the pressing roller,
It is configured to be transmitted to the opening / closing cover. for that reason,
It is necessary to increase the strength of the opening / closing cover, which leads to unnecessary cost increase, and the opening / closing cover requires a force corresponding to such a load, so that the opening / closing operation cannot be easily performed. Occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and an object of the present invention is to make it possible to interlock the opening and closing operation of the opening and closing cover and the pressing and releasing between two rollers of the fixing device. In addition, an image forming apparatus is provided in which the load generated by the interlock is less transmitted to the opening / closing cover, the cost of the opening / closing cover can be reduced, and a simple opening / closing operation can be achieved with a small force. It is in.

[0007]

In order to achieve the above object, the present invention is directed to a fixing device having an opening / closing cover which is opened / closed with respect to an apparatus main body, and a fixing device having two rollers arranged to face each other. An image forming apparatus comprising: an interlocking mechanism that interlocks with the opening and closing of the open / close cover to press and release one of the rollers against the other of the rollers, wherein the interlocking mechanism always includes one of the rollers. A biasing unit that biases the roller so as to be pressed against the other roller, and a pressing position in which one roller is pressed against the other roller by the biasing force of the biasing unit.
Movement for selectively moving one of the rollers to a pressure release position where one of the rollers is moved in a direction away from the other of the rollers and the pressure is released against the urging force of the urging means. A member, a support member that engages with the moving member to move the moving member, and receives a load transmitted to the moving member by the urging force of the urging means; and a member between the opening / closing cover and the supporting member. And a connecting member that moves the support member in conjunction with opening and closing of the open / close cover.

According to this structure, when the opening / closing cover is opened, the supporting member is moved via the connecting member in conjunction with the opening operation, and the moving member is moved by the movement of the supporting member. Thus, one roller is moved to the pressure-releasing position where the roller is moved away from the other roller against the urging force of the urging means. Therefore, the pressure contact between one roller and the other roller can be easily and reliably released in conjunction with the opening operation of the opening / closing cover,
If a recording medium jam occurs between these rollers, the recording medium having the jam can be easily and reliably removed.

When the opening / closing cover is closed, the supporting member is moved in the opposite direction via the connecting member in conjunction with the closing operation, and the moving member is moved in the opposite direction by the movement of the supporting member in the opposite direction. , Whereby the one roller is moved to a pressure contact position where the roller is pressed against the other roller by the urging force of the urging means. Therefore, one roller can be easily and reliably pressed into contact with the other roller in conjunction with the closing operation of the opening / closing cover, and a satisfactory fixing operation can be achieved.

At the time of the opening operation, the moving member moves one roller to the pressure releasing position against the urging force of the urging means, but the load transmitted to the moving member by the urging force of the urging means. Since the support member receives the load, this load is rarely transmitted to the opening / closing cover connected via the connecting member, and the moving member does not resist the urging force of the urging means during the closing operation. Since the moving member is moved, no urging force of the urging means is transmitted to the moving member, and no load is transmitted to the opening / closing cover.

Therefore, while the opening / closing operation of the opening / closing cover and the pressing and releasing between the two rollers of the fixing device can be linked, the load generated by the link is rarely transmitted to the opening / closing cover. Can be configured simply and lightly to reduce costs and to achieve a simple opening and closing operation with a small force.

The invention described in claim 2 is the first invention.
In the invention described in the above, the moving member is swingably supported by the apparatus main body, and one end of the supporting member is engaged with an engaging portion of the moving member, and the other end is Is swingably supported by the device body,
By the opening operation of the opening / closing cover, the support member is rocked via the connecting member, and one of the rollers is opposed to the urging force of the urging means by the moving member engaging with the support member. The other end of the support member is disposed in a direction in which the moving member swings and moves the engagement portion when the support member is moved to the pressure release position. It is characterized by being arranged so as to extend in a direction intersecting with the moving direction of the joint.

According to such a configuration, when the opening / closing cover is opened, the moving member swings to move the engaging portion.
Since the other end of the supporting member whose one end is engaged with the engaging portion is arranged, the load acting on the moving member can be reliably received by this supporting member. In addition, since the connecting member connected to the opening / closing cover is arranged so as to extend in a direction intersecting with the direction in which the engagement portion moves, the load transmitted to the moving member is opened and closed via the connecting member. The transmission to the cover is very little, and the opening and closing cover is further simplified and lightweight,
The cost can be reduced, and a simple opening / closing operation can be achieved with less force.

[0014] The invention according to claim 3 provides the invention according to claim 2.
In the invention described in (1), an engagement protrusion engaged with an engagement part of the moving member is formed at one end of the support member, and the engagement part of the movement member is provided with the engagement member. A guide groove for swinging the moving member by receiving the joint portion and allowing the engagement protrusion to move along the swinging direction of the support member is formed.

According to such a configuration, when the opening / closing cover is opened / closed, the support member is swung via the connecting member in conjunction with the opening / closing operation, and the engaging projection formed at one end thereof moves. The moving member swings by moving within the guide groove of the member. Therefore, the supporting member and the moving member are more reliably swung to prevent the load generated by the interlocking movement from being transmitted to the opening / closing cover, and the opening / closing operation of the opening / closing cover and the gap between the two rollers of the fixing device. A reliable interlocking operation with the pressure contact and release can be ensured.

Further, the invention according to claim 4 is the same as the invention according to claim 3.
Wherein the other end of the support member is disposed in a direction substantially perpendicular to a direction in which the guide groove of the moving member extends when the cover is closed. And

According to such a configuration, the support member is disposed in a direction substantially perpendicular to the direction in which the guide groove of the movable member extends, so that the movable member swings when the opening / closing cover is opened, and the guide member swings. The support member can be reliably arranged in the direction in which the groove moves. Therefore, the load transmitted to the moving member can be more reliably received by the support member, and the load transmitted to the opening / closing cover via the connecting member can be further reduced.

The invention described in claim 5 is the same as the invention described in claim 3.
In the invention described in (4), the guide groove is formed so as to be bent in a direction in which a force for swinging the moving member is reduced with respect to the movable groove portion in which the engagement protrusion can move. And a lock groove for receiving the engagement projection and restricting the movement of the engagement projection when the cover is open.

With this configuration, during the opening operation of the opening / closing cover, the engaging projection moves favorably in the moving groove of the guide groove, and when the opening / closing cover is opened, the engaging projection locks. The movement is restricted by being received in the groove. Since the lock groove is formed to be bent in a direction in which a force for swinging the link member with respect to the moving groove is reduced, in the open state of the opening / closing cover, the lock groove is formed within the lock groove of the engagement protrusion. Movement is reliably regulated. Therefore, when the opening / closing cover is in the open state, one of the rollers can be reliably held at the pressure release position against the urging force of the urging means.

Further, at the time of the closing operation, if only a force for moving the engaging protrusion restricted in the lock groove from the lock groove into the moving groove is applied, the engaging protrusion becomes the guide groove. The opening and closing cover can be closed by moving satisfactorily in the moving groove portion in the opposite direction. Therefore, simple and reliable opening and closing operation of the opening and closing cover can be ensured with less force.

The invention described in claim 6 is the third invention.
The invention according to any one of the first to fifth aspects, characterized in that the engagement protrusion is provided with a roller member for reducing sliding resistance between the engagement protrusion and the guide groove.

According to such a configuration, the engagement protrusion can move in the guide groove in a state where the sliding resistance is reduced by the roller member. Therefore, the opening and closing of the opening and closing cover can be performed with even less force, and a further simple and reliable opening and closing operation of the opening and closing cover can be ensured.

The invention described in claim 7 is the first invention.
In the invention described in any one of (1) to (6), the moving member includes a roller supporting member that movably supports one of the rollers at the press-contact position and the press-release position with respect to the other roller; An operating lever for moving the roller supporting member to the pressure release position is provided independently of the pressing member. .

According to such a configuration, the roller support member can be moved to the pressure release position by operating the operation lever provided independently of the pressing member. If a recording medium jam occurs, the jammed recording medium can be removed only by operating the operation lever without opening the opening / closing cover. That is, according to this configuration, when a jam of the recording medium occurs between the rollers of the fixing device, the user selects whether to open the opening / closing cover or operate the operation lever to cause the jam. Since the recording medium can be removed, operability more suitable for the situation can be improved.

The invention described in claim 8 is the same as the invention described in claim 7.
In the invention described in the above, the pushing member includes an advancing / retracting member that abuts on the roller supporting member so as to be able to advance and retreat, and a link member that pushes the advancing / retreating member, and the operation lever is provided with It is characterized in that it is provided so as to be swingable between a pushing portion and the advancing / retreating member.

According to such a configuration, if the advance / retreat member is pushed by operating the operation lever, the roller support member can be moved to the pressure release position. Therefore, the operation lever can be provided with a simple configuration, and when the recording medium jams between the rollers of the fixing device, it is possible to select whether to open the opening / closing cover or operate the operation lever. Thus, a configuration for removing the jammed recording medium can be realized at low cost.

The invention according to claim 9 is the first invention.
In the invention according to any one of the first to eighth aspects, the open / close cover is an open cover that is opened / closed for attaching / detaching a process cartridge having a photoconductor.

According to such a configuration, by opening and closing the openable cover, the process cartridge can be easily replaced, and the process cartridge can be removed to perform the jam clearance of the recording medium. Therefore, simpler jam processing can be realized.

According to a tenth aspect of the present invention, in the invention according to any one of the seventh to ninth aspects, a cover member that can be opened and closed with respect to the apparatus main body is provided separately from the opening and closing cover. The operation lever can be operated by opening the cover member.

According to such a configuration, when the cover member is opened, the operation lever can be operated from the outside, so that the operability of the operation lever can be further improved.

[0031]

FIG. 1 is a side sectional view showing a main part of an embodiment of a laser printer as an image forming apparatus according to the present invention. In FIG. 1, a laser printer 1 forms a predetermined image on a fed paper 3 or a feeder unit 4 for feeding a paper 3 as a recording medium in a main body casing 2 constituting an apparatus main body. And an image forming unit 5 for the image forming apparatus.

The feeder unit 4 includes a paper feed tray 6 detachably mounted on the bottom of the main body casing 2, a paper pressing plate 7 provided in the paper feed tray 6, and one end of the paper feed tray 6. , A paper feed roller 8 and a paper feed pad 9, and a paper feed roller 8 with respect to the downstream side in the conveyance direction of the paper 3 (hereinafter, the upstream side or the downstream side in the conveyance direction of the paper 3; Transport rollers 10 and 11 provided on the downstream side, and a registration roller 12 provided downstream of the transport rollers 10 and 11 in the transport direction of the sheet 3.

The paper pressing plate 7 is capable of stacking the paper 3 in a stacked manner, and is supported so as to be swingable at an end remote from the paper feed roller 8 so that the near end can be vertically moved. And is urged upward by a spring (not shown) from the back side. for that reason,
The sheet pressing plate 7 is swung downward against the urging force of the spring with the end farther from the sheet feeding roller 8 as a fulcrum as the stacking amount of the sheet 3 increases. The paper feed roller 8 and the paper feed pad 9 are arranged to face each other, and the paper feed pad 9 is pressed toward the paper feed roller 8 by a spring 13 provided on the back side of the paper feed pad 9. . The uppermost sheet 3 on the sheet pressing plate 7 is pressed from the back side of the sheet pressing plate 7 toward the sheet feeding roller 8 by a spring (not shown), and the sheet feeding roller 8 is rotated by the rotation of the sheet feeding roller 8. After being sandwiched between the pats 9, the sheet is fed one by one. The fed sheet 3 is sent to registration rollers 12 by transport rollers 10 and 11. Registration roller 12
Is composed of a pair of rollers, and is configured to send the sheet 3 to the image forming unit 5 after a predetermined registration.

The feeder unit 4 further includes a multi-purpose tray 14, a multi-purpose side paper feed roller 15 for feeding the paper 3 stacked on the multi-purpose tray 14, and a multi-purpose side paper feed pad. Fifteen
a, the multi-purpose side paper feed roller 15 and the multi-purpose side paper feed pad 15a are arranged to face each other, and are provided by a spring (not shown) arranged on the back side of the multi-purpose side paper feed pad 15a. , The multipurpose side paper feed pad 15a is the multipurpose side paper feed roller 1
5. Multipurpose tray 1
The paper 3 stacked on the multi-purpose paper feed roller 15 is rotated by the rotation of the multi-purpose paper feed roller 15.
And the multi-purpose side paper feed pad 15a,
Paper is fed one by one.

The image forming section 5 includes a scanner unit 16,
It includes a process cartridge 17, a transfer roller 24, a fixing device 18, and the like.

The scanner unit 16 is provided at an upper portion in the main body casing 2 and has a laser emitting unit (not shown),
It includes a polygon mirror 19, lenses 20 and 21, and a reflection mirror 22 that are driven to rotate.
As indicated by the dashed line, the polygon mirror 19, the lens 20,
The photosensitive drum 2 of the process cartridge 17 to be described later is passed or reflected in the order of the reflecting mirror 22 and the lens 21.
The surface of No. 3 is irradiated by high-speed scanning.

The process cartridge 17 is disposed below the scanner unit 16 and is configured to be detachably mounted on the main casing 2. The process cartridge 17 includes a photosensitive drum 23 and a scorotron-type charger, a developing roller, and a toner container (not shown).

The toner accommodating portion is filled with a positively charged non-magnetic one-component polymerized toner as a developer, and the toner is carried on a developing roller as a thin layer having a constant thickness. On the other hand, the photosensitive drum 23 is rotatably disposed so as to face the developing roller. The drum main body is grounded, and the surface thereof is formed of a positively charged photosensitive layer made of polycarbonate or the like. .

Then, the surface of the photosensitive drum 23 is uniformly positively charged by a scorotron-type charger with the rotation of the photosensitive drum 23, and is exposed by high-speed scanning of a laser beam from the scanner unit 16, An electrostatic latent image based on predetermined image data is formed, and thereafter, when the electrostatic latent image is opposed to the developing roller, the toner carried on the developing roller and charged positively forms an electrostatic image formed on the surface of the photosensitive drum 23. The latent image, that is, the surface of the photosensitive drum 23 that is uniformly positively charged, is supplied to a portion where the potential is lowered by being exposed by the laser beam, and is visualized by being selectively carried, Thereby, reversal development is achieved.

The transfer roller 24 is disposed below the photosensitive drum 23 so as to face the photosensitive drum 23 while being rotatably supported on the main body casing 2 side. The transfer roller 24 has a metal roller shaft covered with a roller made of a conductive rubber material, and a predetermined transfer bias is applied to the photosensitive drum 23. Therefore, the visible image composed of the toner carried on the photosensitive drum 23 is transferred to the sheet 3 while the sheet 3 passes between the photosensitive drum 23 and the transfer roller 24. The paper 3 onto which the visible image has been transferred is transported via the transport belt 25.
The sheet is conveyed to the fixing device 18.

The fixing device 18 includes the process cartridge 1
7, a heating roller 26, and a pressure roller 2 opposed to the heating roller 26 with the paper 3 interposed therebetween.
7 is provided. The heating roller 26 is made of metal and includes a halogen lamp for heating.
It is supported by a roller shaft 34 which is rotatably supported and fixed inside. The pressure roller 27 is supported by a roller shaft 35 rotatably supported by a roller support member 36 (see FIG. 2) described later.
7 (see FIG. 2) is pressed against the heating roller 26 by the urging force. In the fixing device 18, the toner transferred onto the paper 3 in the process cartridge 17 is thermally fixed while the paper 3 passes between the heating roller 26 and the pressure roller 27.

Paper 3 fixed in fixing device 18
Thereafter, the sheet 3 conveyed to the paper discharge roller 30 by the conveyance rollers 28 and 29 provided on the downstream side of the fixing device 18 and sent to the paper discharge roller 30 is discharged by the paper discharge tray 31 by the paper discharge roller 30. The paper is ejected on top.

The main body casing 2 is provided with an openable / closable cover for opening and closing the process cartridge 17 and a top cover 59 as an open cover. The top cover 59 has a rear end above the process cartridge 17 in the main body casing 2 (hereinafter, the main casing 2 has a front side where the multi-purpose tray 14 is provided, and a rear side where the rear cover 58 described later is provided). ) Is rotatably supported, is disposed in a substantially horizontal direction, and closes the main body casing 2 (the state shown in FIG. 1).
And an open position (a fully open state shown in FIG. 3) in which a front end portion thereof is arranged upward and opens the inside of the main body casing 2. Such a top cover 5
By providing the cover 9 and opening and closing the top cover 59, the process cartridge 17 can be easily replaced, and the process cartridge 17 can be removed to easily perform the jam clearance of the sheet 3. At the rear end side of the top cover 59, a mounting plate 32 for rotatably supporting a connecting rod 41 of the interlocking mechanism 33 described below is formed to protrude downward.

Also, at the rear of the main body casing 2,
The rear cover 58 as a cover member is used for the main body casing 2.
It is provided so that it can be opened and closed freely. This rear cover 5
8 is formed separately from the top cover 59 along the rear wall of the main body casing 2 and is swingably supported at its lower end. By opening the rear cover 58 (in the state shown by the imaginary line), the operation of the operation lever 46 described later can be performed from the outside, and the operability of the operation lever 46 is further improved.

The laser printer 1 is provided with a pressure roller 27 in conjunction with opening and closing of the top cover 59.
Is provided with an interlocking mechanism 33 for pressing and releasing the heating roller 26 with respect to the heating roller 26. FIGS. 2 to 6 are side sectional views showing the configuration of the main part of the interlocking mechanism 33. With reference to FIGS. 2 to 6, the interlocking mechanism 33 will be described in detail below.

As shown in FIGS. 2 to 6, the interlocking mechanism 33 includes a roller support member 36, a spring 37 as an urging means, a linear motion rod 38 as an advance / retreat member, and an operation lever 4
6, a link member 39, a support plate 40 as a support member, and a connection rod 41 as a connection member. In each of the members of the interlocking mechanism 33, the linear motion rod 38 and the link member 39 constitute a pushing member, and the pushing member and the roller supporting member 36 constitute a moving member. Further, in the present embodiment, these members of the interlocking mechanism 33 are provided on both sides of the fixing device 18 of the main body casing 2, however, in the following description, only one side shown in FIGS. State.

4 to 6, the roller support member 36 has a plate shape, and its front end is located below the heating roller 26 and on the side in the width direction of the pressure roller 27 via a support shaft 42. The bearing 43 is swingably supported by the main casing 2 and is provided behind the support shaft 42.
And a rod-shaped contact rod 44 protruding further rearward from the bearing portion 43 are integrally formed. The roller shaft 35 of the pressure roller 27 is rotatably supported by the bearing 43.

The spring 37 has one end connected to the contact rod 4.
4, and the other end of the main casing 2 is positioned almost directly above the base end 45.
And urges the base end 45 of the contact rod 44 upward.

Therefore, as shown in FIG. 4, the roller support member 36 is always swung upward by the biasing force of the spring 37 about the support shaft 42 as a fulcrum, and is rotatably supported by the bearing portion 43. The pressing roller 27 is pressed against the heating roller 26.

The linear motion rod 38 has a rod shape, and is disposed substantially vertically above the contact rod 44 of the roller support member 36. The linear motion rod 38 is vertically slidably supported in the main body casing 2 so as to be able to contact the contact rod 44 of the roller support member 36 so as to be able to advance and retreat.

Therefore, as shown in FIG. 4, when the linear motion rod 38 is retracted upward and the lower end portion of the linear motion rod 38 does not press the contact rod 44 of the roller support member 36, the above-described operation is performed. Thus, by the urging force of the spring 37,
While the pressing roller 27 is located at a pressing position where the pressing roller 27 is pressed against the heating roller 26, as shown in FIG. 5, the linear motion rod 38 is advanced downward, and the lower end of the linear motion rod 38 is a roller supporting member. When pressing the contact rod 44 of the roller support member 3, the contact rod 44 is pushed downward.
6 is swung downward about the support shaft 42 as a fulcrum against the urging force of the spring 37, and the pressure roller 27 is
6 is located at the pressure release position which is moved in the direction away from 6. That is, the pressure roller 27 can be selectively moved to the pressure contact position and the pressure contact release position with respect to the heating roller 26 by the swing of the roller support member 36 due to the advance and retreat of the linear motion rod 38.

The operation lever 46 has a plate shape and is disposed above the upper end of the linear motion rod 38.
The front end of the support shaft 4
The main unit 2 is swingably supported by the main body casing 2 through a rear end 7, and a rear end portion thereof is an operation unit 48 for a user to manually operate. The support shaft 47 and the operation unit 4
8, a linear motion rod 38
A contact protrusion 49 for making contact with the upper end portion of the first member is formed to protrude downward.

Then, as shown in FIG.
8 is always in a retracted state in which the abutment rod 44 of the roller support member 36 is not pressed, but as shown in FIG. 5, the operation lever 46 is pivoted downward about the support shaft 47 as a fulcrum. For example, the contact protrusion 49 can push the upper end of the linear motion rod 38 to cause the linear motion rod 38 to advance downward, thereby causing the roller support member 36 to swing, The pressure roller 27 can be moved from the pressure contact position to the pressure release position. Therefore, for example, if the user presses the operation portion 48 of the operation lever 46 downward with a finger, the pressure roller 27 can be moved to the pressure release position.

The link member 39 has a plate shape, and is arranged opposite to the roller support member 36 at a predetermined interval in the vertical direction.
It is swingably supported by the main body casing 2 via the support shaft 51. The link member 39 is in contact with the lower surface of the rear end portion and the upper surface of the operation lever 46.
A pushing protrusion 50 is provided as a pushing portion for pushing the linear motion rod 38 downward through the support plate, and a support plate 40 described below is provided between the middle of the longitudinal direction and the front end thereof. A guide groove 52 is formed as an engaging portion with which the engaging protrusion 55 is engaged.

The guide groove 52 is formed as a substantially L-shaped elongated hole for receiving the engagement protrusion 55 and allowing the movement of the engagement protrusion 55 along the swinging direction of the support plate 40. The movable groove 53 in which the engagement protrusion 55 can move, and the lock groove 54 that receives the engagement protrusion 55 and regulates the movement thereof in the open state of the top cover 59 are continuously formed. I have. More specifically, the moving groove 53 is
The engagement protrusion 55 is formed as a long hole along the longitudinal direction so as to be movable, and the lock groove 54 swings the link member 39 relative to the movement groove 53 when the top cover 59 described later is opened. Direction in which the force to reduce the force (the direction in which the engagement protrusion 55 that moves the guide groove 52 along the swinging direction of the support plate 40 exceeds the fulcrum, more specifically,
The moving groove 53 is formed to be bent in an obliquely upward direction with respect to the longitudinal direction of the long hole.

The support plate 40 has a substantially rectangular flat plate shape and is disposed substantially vertically, and has an engagement protrusion 55 inserted into the guide groove 52 of the link member 39 at one end thereof.
The link member 39 is formed so as to protrude so as to be movably engaged in the guide groove 52, and the other end thereof is located above the guide groove 52 of the link member 39 when the top cover 59, which will be described later, is opened. The guide groove 52 is swingably supported by the main body casing 2 via a support shaft 56 arranged in a direction in which the guide groove 52 moves by swinging the guide 39. As a result, when the top cover 59 is closed, the support plate 40
Is arranged so as to extend in a direction substantially orthogonal to the direction in which the link 37 extends, and is configured to be able to receive a load transmitted to the link member 39 by the urging force of the spring 37 during an opening operation described later. .

The engaging projection 55 has a guide groove 5
A roller member 57 is provided rotatably to reduce sliding resistance between the roller member 2 and the roller member 57.

As shown in FIGS. 2 and 3, the connecting rod 41 has a rod shape, one end of which is rotatably mounted on the mounting plate 32 of the top cover 59 and the other end of which is supported. It is rotatably attached to one end of the plate 40 where the engagement protrusion 55 is provided. As a result, the connecting rod 41 intersects with the direction in which the guide groove 52 moves when the link member 39 swings during the opening operation of the top cover 59, which will be described later, and moves outward in the swing locus of the link member 39. It is arranged to extend.

Next, the interlocking mechanism 33 constructed as described above.
Will be described.

First, in the closed state of the top cover 59, as shown in FIGS.
9, the end of the connecting rod 41 on the support plate 40 side
Since the support plate 40 has been moved further back,
The engagement protrusion 55 is located at the rear end of the movement groove 53 in the guide groove 52 of the link member 39 at a position pivoted rearward (clockwise) with the fulcrum 6 as a fulcrum. In this state, the link member 39 is in a state where the guide groove 52 side is pivoted downward and the pushing protrusion 50 side is pivoted upward (clockwise) with the support shaft 51 as a fulcrum.
Since the pushing protrusion 50 of the link member 39 is separated from the upper surface of the operation lever 46, the operation lever 46
Is in a free state in which the linear motion rod 38 is not pushed. Therefore, the linear motion rod 38 is
As described above, the roller support member 36 is swung (clockwise) by the urging force of the spring 37 so as to move the pressure roller 27 to the pressure contact position. It has been moved. Therefore, when the top cover 59 is closed, the pressure roller 27 is pressed against the heating roller 26.

On the other hand, when the top cover 59 is opened from this closed state, as shown in FIG. 6, the connecting rod 41 interlocked with the top cover 59 causes the top cover 5 to move.
9, the end of the connecting rod 41 on the support plate 40 side is moved further forward, so that the support plate 40 is
It is swung forward (counterclockwise) around 6. Then, the engaging projection 55 is moved to the moving groove 53 of the guide groove 52.
Is moved forward in the longitudinal direction of the support plate 40 along the swinging direction of the support plate 40. Therefore, the link member 39 has the support shaft 51 as a fulcrum and the guide groove 52 side is upward, that is, the support shaft of the support plate 40. In the direction toward 56, the pushing projection 50
The side is swung downward (counterclockwise).

Then, the pushing protrusion 5 of the link member 39 is formed.
0 presses the upper surface of the operation lever 46, so that the operation lever 46 swings downward (counterclockwise) with the support shaft 47 as a fulcrum. The linear motion rod 38 is abutted on the upper end portion and is advanced downward. When the linear motion rod 38 is advanced downward, the lower end of the linear motion rod 38 presses the contact rod 44 of the roller support member 36, so that the urging force of the spring 37 is applied as described above. In contrast, the roller support member 36
Is swung (counterclockwise) to move the pressure roller 27 to the pressure release position.

When the top cover 59 is in the open state (full open state) as shown in FIG. 3, the engaging protrusion 55 of the support plate 40 is moved to the lock groove 54 of the guide groove 52 as shown in FIG. And its movement is reliably regulated. Therefore, when the top cover 59 is in the open state, the pressure roller 27 is reliably held at the pressure release position against the urging force of the spring 37.

When the top cover 59 is closed from this open state, the connection rod 41 interlocked with the top cover 59 is pushed by the top cover 59, and the top cover 59 is closed. Is moved further rearward, whereby the support plate 40 swings rearward (clockwise) about the support shaft 56. Then, the engagement protrusion 55 comes out of the lock groove 54 in the guide groove 52 of the link member 39, and moves the movement groove 53 to the support plate 4.
0, the link member 39 moves downward with the support shaft 51 as a fulcrum, the guide groove 52 side with the support shaft 51 as a fulcrum, and the push projection 50 side with the support shaft 51 as a fulcrum. Rocked (clockwise). Then, the pressing of the pushing protrusion 50 of the link member 39 against the upper surface of the operation lever 46 is released, so that the pressure roller 27 is moved relative to the heating roller 26 in the closed state of the top cover 59 as described above. To be pressed.

According to such an interlocking mechanism 33, the pressing of the pressure roller 27 against the heating roller 26 can be released in conjunction with the opening operation of the top cover 59.
If the paper 3 is jammed between the pressure roller 27 and the heating roller 26, the top cover 59 is opened, so that the jammed paper 3 can be easily and reliably removed. it can. After the jammed paper 3 is removed, the top cover 5 is removed again.
When the shutter 9 is closed, the pressure roller 27 can be pressed against the heating roller 26 in conjunction with the closing operation, so that a satisfactory fixing operation can be achieved simply and reliably.

In this interlocking mechanism 33, at the time of the opening operation, the link member 39 pushes the linear motion rod 38 via the operation lever 46 against the urging force of the spring 37.
The load transmitted to the link member 39 by the urging force of the spring 37 is in the swing direction of the link member 39, that is, the support plate 4 in which the guide groove 52 of the link member 39 moves.
Since the load is transmitted in the direction toward the zero support shaft 56, the load is reliably received by the support plate 40. On the other hand, the connecting rod 41 connected to the top cover 59 is
The support plate 4 on which the guide groove 52 of the link member 39 moves.
Link member 3 that intersects the direction toward the support shaft 56
9, the load transmitted to the link member 39 is very rarely transmitted to the top cover 59 via the connecting rod 41. . Also, the top cover 59
Of the linear motion rod 3 of the link member 39 during the closing operation of
8 is released, so that no load is transmitted to the link member 39, and therefore no load is transmitted to the top cover 59.

Therefore, the opening / closing operation of the top cover 59 and the pressing roller 27 and the heating roller 2 of the fixing device 18 are performed.
While the pressure contact and release of 6 can be linked,
Since the load generated by the interlock is rarely transmitted to the top cover 59, the strength is not so much required. Therefore, the top cover 59 can be configured to be simple and lightweight, and the cost can be reduced. Further, a force corresponding to such a load is not required for opening and closing the top cover 59, and the opening and closing operation can be easily performed with a small force.

In addition, in the interlocking mechanism 33, when the top cover 59 is opened and closed, the support plate 40 is swung in conjunction with the opening and closing operations, and the engaging projection 55 moves within the guide groove 52 of the link member 39. By doing so, since the link member 39 is more reliably swung, the top cover 59
The transmission of the load generated by the interlock is more reliably prevented.

Further, in this interlocking mechanism 33, when the top cover 59 is opened, the engaging projection 55 is
Of the top cover 59
Is in the open state, the engagement protrusion 55 is
And the locking groove 54 of the engaging projection 55
Since the movement in the inside is surely restricted, the top cover 59
In the open state, the pressure roller 27 can be securely held at the pressure release position.

The lock groove 54 is provided in the movable groove 5
In contrast to the third embodiment, when the top cover 59 is closed from the open state, the locking groove 54 is formed in a direction in which the force for swinging the link member 39 during the opening operation of the top cover 59 is reduced. As long as a force for moving the inner engagement protrusion 55 from the lock groove 54 into the movement groove 53 (that is, a force to move over the fulcrum in the state shown in FIG. 6) is given, the engagement protrusion 55 is guided. It can be moved into the moving groove 53 of the groove 52,
Further, the opening / closing operation of the top cover 59 is realized with less force.

Further, the guide groove 52 is formed in the engagement protrusion 55.
Roller member 5 for reducing sliding resistance between
7 is rotatably provided, so that the engagement protrusion 55
The guide member 52 is moved in the guide groove 52 in a state where the sliding resistance is reduced by the roller members 57. Therefore, the opening / closing operation of the top cover 59 can be realized with less force.

Further, in the interlocking mechanism 33, since the operation lever 46 is provided as a member independent of the link member 39, the paper 3 is jammed between the pressure roller 27 and the heating roller 26. In this case, even if the top cover 59 is not opened, the user opens the rear cover 58 as shown in FIG.
Is pressed down with a finger, the pressure contact of the pressure roller 27 with the heating roller 26 is released, and the jammed sheet 3 can be removed. That is, in the interlocking mechanism 33, when the paper 3 is jammed between the pressure roller 27 and the heating roller 26 of the fixing device 18, the top cover 59 is opened or the operation lever 46 is moved. Since the jammed sheet 3 can be removed by selecting whether to operate or not, the operability more suitable for the situation is improved.

Further, since the operation lever 46 is swingably provided between the pushing protrusion 50 of the link member 39 and the linear motion rod 38, the arrangement of the operation lever 46 can be simplified. With a simple configuration, it is realized at low cost.

In this embodiment, the operation lever 46
Of the link member 39 and the linear motion rod 38
The operation lever 46 is not provided, but the pushing protrusion 5 of the link member 39 is provided.
0 may directly push the linear motion rod 38.

In such a case, for example, the link member 39 and the linear rod 38 are formed integrally,
The link member 39 and the linear motion rod 38 may be configured as one pushing member.
9 and a linear motion rod 38, and a roller support member 36 are integrally formed, and the link member 39, the linear motion rod 38, and the roller
It may be configured as one moving member.

[0076]

As described above, according to the first aspect of the present invention, the opening / closing operation of the opening / closing cover and the pressing and releasing of the two rollers of the fixing device can be linked with each other while opening and closing. The load generated by interlocking is less likely to be applied to the cover, and the open / close cover is configured to be simple and lightweight,
The cost can be reduced, and a simple opening and closing operation can be achieved.

According to the second aspect of the present invention, the load transmitted to the moving member can be reliably received by the support member, and the load transmitted to the opening / closing cover via the connecting member is extremely small. can do. Therefore, the opening / closing cover can be further simplified and lightened to reduce the cost, and a simple opening / closing operation can be achieved with less force.

According to the third aspect of the present invention, the supporting member and the moving member are more reliably swung to prevent the load generated by the interlocking operation from being transmitted to the opening / closing cover, and the cover member is moved. A reliable interlocking operation between the opening and closing operation of the fixing device and the pressing and releasing of the two rollers of the fixing device can be ensured.

According to the fourth aspect of the present invention, the load transmitted to the moving member can be more reliably received by the support member, and the load transmitted to the opening / closing cover via the connecting member can be reduced. It can be even less.

According to the fifth aspect of the present invention, when the opening / closing cover is in the open state, one of the rollers can be reliably held at the pressure release position against the urging force of the urging means, and In addition, it is possible to easily and reliably open and close the opening and closing operation with less force.

According to the sixth aspect of the present invention, the opening / closing cover can be opened and closed with even less force.
Further, a simple and reliable opening and closing operation of the opening and closing cover can be ensured.

According to the seventh aspect of the invention, when a recording medium jam occurs between the rollers of the fixing device, it is selected whether to open the opening / closing cover or operate the operation lever. Then, the jammed recording medium can be removed, so that the operability more suitable for the situation can be improved.

According to the eighth aspect of the present invention, the operation lever can be provided with a simple configuration, and when the recording medium is jammed between the rollers of the fixing device, the opening / closing cover is opened. A configuration for removing the jammed recording medium by selecting whether to operate the operation lever or the operation lever can be realized at low cost.

According to the ninth aspect of the present invention, it is possible to realize a further simple jam processing.

According to the tenth aspect, the operability of the operation lever can be further improved.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a main part of an embodiment of a laser printer as an image forming apparatus of the present invention.

FIG. 2 is a side sectional view showing a configuration of a main part of the interlocking mechanism (a closed state of a top cover) in the laser printer shown in FIG. 1;

FIG. 3 is a side sectional view showing a configuration of a main part of the interlocking mechanism (opening state of a top cover) in the laser printer shown in FIG. 1;

FIG. 4 is an enlarged sectional side view of a main part configuration (top cover closed state) of the interlocking mechanism in FIG. 2;

FIG. 5 is an enlarged side sectional view of a main part configuration (open state of a top cover) of an interlocking mechanism in FIG. 3;

FIG. 6 is an enlarged side sectional view of a configuration of a main part of the interlocking mechanism in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser printer 2 Main body casing 17 Process cartridge 18 Fixing device 23 Photosensitive drum 26 Heating roller 27 Pressure roller 33 Interlocking mechanism 36 Roller support member 37 Spring 38 Linear motion rod 39 Link member 40 Support plate 41 Connecting rod 46 Operating lever 50 Pushing Projection 52 Guide groove 55 Engagement projection 53 Moving groove 54 Lock groove 57 Roller member 58 Rear cover 59 Top cover

Claims (10)

[Claims] An opening / closing cover which is opened and closed with respect to an apparatus main body, and a fixing device having two rollers arranged to face each other, wherein one of the rollers is driven in response to opening and closing of the opening / closing cover. An image forming apparatus including an interlocking mechanism that presses and releases the roller, wherein the interlocking mechanism always includes an urging unit that urges one of the rollers so as to be pressed against the other of the rollers. A pressing position at which one of the rollers is pressed against the other roller by the urging force of the urging means, and one of the rollers is separated from the other roller against the urging force of the urging means. A moving member that selectively moves one of the rollers to a pressure-releasing position where the pressure contact is released by being moved in the direction, and engaging with the moving member to move the moving member; A support member for receiving a load transmitted to the moving member by the urging force of the urging means, a connection between the open / close cover and the support member, and movement of the support member in conjunction with opening / closing of the open / close cover An image forming apparatus, comprising: a connecting member. 2. The moving member is swingably supported by the apparatus main body. One end of the supporting member is engaged with an engaging portion of the moving member, and the other end of the supporting member is engaged with the engaging portion of the moving member. The support member is swingably supported by the apparatus main body, and the opening and closing cover is opened to swing the support member via the connecting member, and the one of the moving members is engaged with the support member. When the roller is moved to the pressure release position against the urging force of the urging means, the other end of the support member moves in a direction in which the moving member swings and the engaging portion moves. And the connecting member is arranged so as to extend in a direction intersecting with a moving direction of the engaging portion.
An image forming apparatus according to claim 1. 3. An engaging projection that is engaged with an engaging portion of the moving member is formed at one end of the support member, and the engaging portion of the moving member is provided with the engaging protrusion. A guide groove for receiving the protrusion, allowing the movement of the engagement protrusion along the swing direction of the support member, and swinging the moving member is formed. Item 3. The image forming apparatus according to Item 2. 4. In the closed state of the opening / closing cover, the other end of the support member is disposed in a direction substantially orthogonal to a direction in which the guide groove of the moving member extends. The image forming apparatus according to claim 3, wherein: 5. The guide groove, wherein the guide groove is formed to be movable in a direction in which a force for swinging the movable member is reduced with respect to the movable groove in which the engagement protrusion is movable. A lock groove for receiving the engagement protrusion in the open state of the open / close cover and restricting the movement thereof.
The image forming apparatus according to claim 3. 6. The engaging projection is provided with a roller member for reducing a sliding resistance between the engaging projection and the guide groove. An image forming apparatus according to claim 1. 7. The moving member includes one of the rollers,
A roller support member that movably supports the other roller at the pressure contact position and the pressure contact release position; and a pushing member that pushes the roller support member, wherein the roller support member releases the pressure contact. The image forming apparatus according to any one of claims 1 to 6, wherein an operation lever for moving the operation member to a position is provided independently of the pushing member. 8. The pushing member includes an advancing and retreating member that abuts on the roller support member so as to be able to advance and retreat, and a link member that pushes the advancing and retreating member. The image forming apparatus according to claim 7, wherein the image forming apparatus is swingably provided between a moving unit and the advance / retreat member. 9. The image forming apparatus according to claim 1, wherein the open / close cover is an open cover that is opened / closed for attaching / detaching a process cartridge having a photosensitive member. 10. A cover member that can be opened and closed with respect to the apparatus main body is provided separately from the opening and closing cover, and the opening of the cover member allows the operation lever to be operated. The image forming apparatus according to claim 7, wherein: