JPH0132052Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image recording apparatus having a fixing device that fixes a toner image by holding and conveying an image support material between a pair of rollers.

For example, a heated fixing roller whose circumferential surface is coated with a release material and a pressure roller having an elastically deformable surface layer such as rubber are brought into pressure contact with each other, and an image support material is passed between the two rollers to form a toner image. Fixing devices configured to heat and melt fix images are widely used, but in such fixing devices, the rollers are prone to damage due to various reasons (damage to the rollers may result in poor fixing, offset, and image support. (The material becomes frequently wrapped around the rollers.)
Therefore, the rollers must be easy to repair or replace, and since rollers are easily soiled with toner and paper dust (in this case, the same inconvenience as above occurs frequently), the rollers must be easy to clean. It is desired that the jammed image support material be easily removed. For this reason, it is desirable to have a configuration in which the fixing device can be pulled out from the set position within the image recording apparatus, but in this case, if the image support material discharging means on the rear side of the roller pair is also pulled out integrally, it is difficult to take the above measures. For this reason, it is desirable to be able to pull out only the main body of the fixing device, which has a pair of rollers, in addition to the ejection means, but the present invention prevents damage to the rollers when the main body of the fixing device is pulled out from the set position in such a device. Our main objective is to provide a fixing device with a simple structure, which prevents the fixing device from attaching to the fixing device and prevents the ejecting means from forming an ejecting path unless the main body is returned to the set position, thereby preventing erroneous operation. purpose.

To achieve the above object, the present invention includes a pair of rollers that sandwich and convey a toner image support material, and integrally includes a fixing unit that can be pulled out from the apparatus main body and a separation member that separates the support material from the roller. The image recording apparatus has an apparatus main body and an openable/closable discharge unit, and when the discharge unit is in an open state, the fixing unit can be pulled out, and when the discharge unit is in a closed state, the fixing unit can be pulled out. The feature is that the unit is prevented from being withdrawn.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an electrophotographic copying apparatus to which the fixing device of the present invention can be applied.

In the figure, reference numeral 1 denotes a photosensitive drum that has an electrophotographic photosensitive member on its circumferential surface and rotates in the direction of the arrow. As the drum 1 rotates, it is first uniformly charged by a corona discharger 2, and then the original to be copied O is charged through a slit 9.
As a result, an electrostatic latent image corresponding to the document O is formed on the drum 1.

The original O is placed on the original table glass O' and is scanned by scanning mirrors 3 and 4 that move in the direction of the arrow at a speed ratio of 1:1/2. At this time, the original is illuminated by an illuminator 5 that moves integrally with the mirror 3. The document O scanned in this manner is imaged by the lens 6, and the imaged light beam is directed to the fixed mirrors 7 and 8.
and enters the drum 1 through the slit 9.

The latent image is developed by a developing device 10 to form a toner image. This toner image is transferred to the transfer charger 1
1 is transferred to paper P under the action of 1. The paper P is sent out one by one from the supply cassette 12 by a delivery roller 13, guided by a guide plate 14, and sent to a timing roller 15. The roller 15 advances the paper in time with the scanning of the original, and the paper is guided by the guide plate 16 and sent to the transfer position, where the toner image is transferred as described above. After the transfer, the paper P is separated from the drum 1 and sent to the fixing device by the belt 17. The fixing device includes a fixing roller 18 having an internal heat source and a pressure roller 19 in pressure contact with the fixing roller, each of which rotates in the direction of the arrow to nip and convey the paper. At this time, the toner image supporting surface of the paper P is pressed against the roller 18, and the toner image is melted by the heat of the roller 18, thereby fixing the image to the paper P. The paper P that has passed through the pressure contact portions of the rollers 18 and 19 is separated from the roller 18 by a separation claw 20 whose tip is brought into contact with the roller 18, and a separating claw 20, which faces the separation claw 20, separates the paper P from the roller 18. The paper is guided to discharge rollers 22 and 23 by a guide plate 21' forming a passage. The rollers 22 and 23 rotate in the directions of the arrows, respectively, and pinch and convey the paper P coming out from the rollers 18 and 19, and discharge it onto the storage tray 29.

Note that the toner remaining on the drum 1 after the transfer is cleaned by a cleaner 25, and the drum 1 is used again for the image forming process.

The above-mentioned means are arranged in the outer box B of the copying apparatus main body, which has the document table O' fixed to the upper surface.The rollers 18 and 19 open the front door (not shown) of the box B. After that, it can be taken out of the box and installed at a predetermined position inside the box.

That is, the roller 18 is rotatably supported by the upper plates 24a and 24b, while the roller 19 is rotatably supported by the lower plates 25a and 25b.
As will be described later, the upper plates 24a and 24b are pivotally attached to the lower plate 25 so as to be rotatable. Lower plate 25
a and 25b are fixed to a seat 26 as described later, and this seat 26 is slidably supported by a guide member 27 fixed at an immovable position within the exterior box B of the main body of the copying apparatus. This guide member 27 guides the seat 26 in a direction perpendicular to the drawing. When the support plate 28, which will be described later, is tilted from the normal position to the temporary position, the base 26, side plates 24a, 24b, 25a, 2
5b, the rollers 18 and 19 are moved toward the front of the page in FIG. 1 under the guidance of the guide member 27.
It can be pulled out from the set position in the box B where it performs the fixing action. For simplicity, the side plates 24a, 24
b, 25a, 25b and members and means attached thereto (e.g. rollers 18, 19, seat 26)
The part consisting of these parts will be referred to as the main body part of the fixing device.

The fixing device will be described in more detail below.

In each of the following figures, the fixing roller 18 is made of a metal cylindrical roll with a thin coating 18' of a release material such as tetrafluoroethylene resin on the circumferential surface, and a heater 18'' is placed in the hollow of this roller. The heater 18'' heats the roller 18 and melts the toner image on the paper P pressed against the roller 18. The pressure roller 19 is formed by covering a core metal roll 19' with a layer 19'' of a thick elastic material having mold releasability such as silicone rubber.
As a result, the elastic layer 19'' is elastically deformed at the pressure contact portion of both rollers, and the paper P
The rollers 18 and 19 are configured to sandwich and press the paper for a time required for fixing with respect to the rotational speed of the rollers 18 and 19. Note that the rotational driving force from the motor is applied to the roller 18.
is transmitted to a gear 18 fixed to the shaft of the roller 18, thereby rotating the roller 18 in the direction of the arrow.
On the other hand, the roller 19 rotates as a result of the roller 18 due to frictional force. Note that the paper fed by the belt 17 is guided by a guide plate 21 and fed between rollers 18 and 19.

Now, the roller 18 is rotatably supported by upper plates 24a and 24b provided at both ends, respectively. To be more specific, both ends of the roller 18 are provided with bearings 31, respectively.
It is rotatably supported by a and 31b. on the other hand,
The upper plates 24a and 24b are provided with U-shaped bearing support cutouts 30a and 30b, respectively, which are open at the bottom. The bearings 31a, 31b are pushed into the cutout portions 30a, 30b somewhat tightly, and the roller 18 is thereby moved between the side plates 24a, 24b.
4b. The bearings 31a, 31b cannot be removed from the side plates 24a, 24b by rotational movement of the side plates 24a, 24b, which will be described later, but when the side plates 24a, 24b are rotated from the normal position shown in FIG. 2 to the temporary position shown in FIG. By applying a light blow to the bearings 31a, 31b, the bearings can be easily removed from the U-shaped cutout of the side plate. That is, the roller 18 can be removed from the side plates 24a, 24b.

Further, the lower plates 25a and 25b are similarly provided with U-shaped cut-out portions 32a and 32b, respectively, which are open at the top. And in these cutout parts 32a, 32b,
Bearings 33a and 33b, which rotatably supported both ends of the roller 19, are slightly loosely inserted into the bearings 33a and 33b.
5b. and upper plates 24a, 24b
When the rollers 19 are rotated to the temporary position, the rollers 19 can be removed integrally with their bearings 33a, 33b from the side plates 25a, 25b without the use of tools. Further, the guide plate 21 is fixed to the lower plates 25a and 25b.

The upper plates 24a and 24b are connected by a stay 34 and fixed to each other. On the other hand, lower plate 2
5a and 25b are connected by the pedestal 26 and fixed to each other. Therefore, the upper side plates 24a, 24b
are the pins 3 implanted in the lower plates 25a and 25b, respectively.
It is rotatably supported by 5a and 35b.

Further, pins 36a and 36b are implanted in the lower plates 25a and 25b at positions opposite to the pins 35a and 35b with respect to the roller 19, respectively. Hook members 37 are attached to the pins 36a and 36b, respectively.
a and 37b are rotatably supported. on the other hand,
A rod 38 is suspended between the upper plates 24a and 24b. To be more specific, long holes 39a and 39b are formed in the side plates 24a and 24b, respectively, and both ends of the rod 38 are fitted into the long holes so as to be movable in the longitudinal direction of the holes. On the other hand, Rod 3
8 is provided with a horizontal hole, and the bolt 4 is inserted into this horizontal hole.
0 is inserted. The threaded portion of this bolt 40 is inserted into a hole provided in the stay 34, and a nut 41 is screwed into the portion protruding from the hole of the stay. The rod 38 is thus supported by the head of the bolt 40, and the bolt 40 is supported by the nut 41.
It is supported by the stay 34 by. Therefore, by adjusting the rotation of the nut 41, the position of the rod 38 can be adjusted in the longitudinal direction of the elongated hole. As a result, the rotation shaft 36a of the hook members 37a, 37b,
The distance between 36b and this rod 38 can be adjusted.
And the hook portions 3 of the hook members 37a, 37b
7'a and 37'b are hooked onto the rod 38 and locked thereto.

In this way, the roller 18 is pressed against the roller 19, and as described above, the elastic layer 19'' of the roller 19 is
The image supporting paper P is compressed and deformed to convey the image supporting paper P under pressure, thereby forming a nip portion in which the toner image is fixed. When the hook portions 37'a and 37'b of the hook member are hooked and locked onto the rod 38 in this manner, the roller 18 and its supporting side plates 24a and 24b are said to be in their normal positions. (See FIGS. 2 and 3) The pressing force of the roller 18 against the roller 19 in the normal position can be adjusted by adjusting the nut 41. One set of adjusting means consisting of a bolt 40 and a nut 41 is provided at each end of the roller, and can be adjusted independently of each other.

Furthermore, regardless of whether the main switch of the copying device is ON or OFF, whether the copying device is copying or not, or whether there is paper P between the rollers 18 and 19,
The operator manually rotates the hook members 37a, 37b clockwise around the shafts 36a, 36b to remove the hooks from the rod 38 (see FIG. 4), or further manually rotates the upper plates 24a, 24b to the shaft 35a. ，
The roller 18 is rotated counterclockwise around 35b.
Unless the roller 18 is retracted from the roller 19 (see FIG. 5), the roller 18 is always in pressure contact with the roller 19. However, the performance of recent silicone rubber used as layer 19'' has improved to such an extent that it hardly causes permanent deformation even if it is constantly compressed.
There is no problem even if the roller 18 is always pressed against the
When the heater 18'' is deenergized, the roller 1
8 and 19 are not thermally expanded, so the pressing force between them is small.

Next, the aforementioned separation claw 20, guide plate 21',
The discharge rollers 22, 23 and the tray 29 are connected to the support plate 2.
It is attached to 8. This support plate 28 is rotatably supported by a shaft 42 which is supported at an immovable position on the side of the main body of the copying apparatus. The support plate 28 can be manually rotated about 90 degrees counterclockwise about the shaft 42 from the position shown in FIG. 2 by the operator. Therefore, the roller 2 is integrated with this support plate 28.
2, 23, guide plate 21', claw 20, roller 1
Make a big retreat from behind 8 and 19. For the sake of simplicity, the portion consisting of the support plate 28, means attached thereto, members 20, 21', 22, 23, etc. will be referred to as the fixing device paper ejection system portion.

A pin 43 is implanted in the support plate 28 as shown in the second figure, and a hook 44 is swingably supported around the pin 43. The other end of a torsion spring 45 whose one end is pressed against the rear wall of the support plate 28 is locked to the hook 44, thereby giving the hook 44 the ability to rotate counterclockwise. There is. However, the range of rotation in the clockwise direction is limited by the protrusion 28' of the support plate 28. The hook 44 is provided with a notch 44', which is cut out when the support plate 28 is in the normal position shown in FIG. The notch 44' engages with a fixing rod 46 fixed in an immovable position within the copying machine body box B, thereby holding the support plate 28 in its normal position. To lower the support plate 28 to the temporary position in which the rear of the rollers 18, 19 is opened and the paper ejection path is eliminated, the operator presses the bent plate portion 44'' of the hook 44, and the hook 44 is pressed against the spring 45. The notch 44' rotates counterclockwise against the biasing force of the fixing rod 4.
6, the support plate 28 can be manually rotated counterclockwise. To return the support plate 28 from the temporary position to the normal position, the operator manually pushes the support plate 28.
Just rotate it clockwise. A cam surface 44 is formed at the tip of the hook 44, and as the hook 44 rotates, the cam surface 44 comes into contact with the lower surface of the rod 46, whereby the hook 44 is rotated clockwise to open the notch 44. ' fits into the rod 46.

Note that when the support plate 28 is in the position shown in FIG.
0 is in contact with the roller 18.

Now, as mentioned above, reference numeral 27 is a guide rail fixed in an immovable position on the main body of the copying machine, and has a 90° bent portion 27' with respect to the bottom surface on both sides and a 90° bent portion 27' with respect to the bottom surface.
On the other hand, the side plates 25a,
The fixed seat 26 of 25b also has a 90° bend 26' with respect to the bottom surface on both sides thereof. The pedestal 26 is slidably fitted to the guide rail 27 as shown in the figure, so that the main body of the fixing device can be manually pulled out from the fixed position in the main body box B by the operator, and can also be pulled out from the front. It is designed to be inserted deep inside. As shown in FIG. 6, an opening 47 is provided on the front side of the seat 26. A stopper 48 is provided on the near side of the rail 27 and is biased to rotate upward by a spring 49. This stopper 48 is constructed from the end of an operating member 51 that is rotatably supported on a shaft attached to the rail 27, but in any case, the main body of the fixing device is located at a set position within the main body of the copying machine. At this time, the stopper 47 is held in the opening 48 of the pedestal by the urging force of the spring 49, thereby preventing the main body of the fixing device from being inadvertently pulled out from the main body of the copying apparatus. To pull out the main body of the fixing device as described above, the support plate 28 is brought down to the temporary position as described later, and then the member 51 is manually pushed upward to retract the stopper 48 below the seat 26. . An opening 52 is also provided at the back of the seat 26 as shown in FIG. 48 fits into this opening 52 by the biasing force of the spring 49,
Further withdrawals are now blocked. Of course, in this state, if the operator pushes the presser foot 51 upward to retract the stopper 48 from the opening 52 and then pulls out the fixing device main body, the fixing device can be completely removed from the copying device main body. In the state shown in FIG. 7, the bent portion 26' of the seat 26 will not interfere with the bent portion 27'' of the guide rail, and the main body of the fixing device will not fall.

Now, at the lower part of the support plate 28, a protrusion 53 is provided as shown in the second and sixth figures, and on the other hand, the base 28
6 and the guide rail 27 have notches 54 and 55, respectively.
is provided. Therefore, when the rollers 18 and 19 are located at the set position where they perform the fixing action, in other words, when the main body portion of the fixing device is located at the set position within the copying apparatus main body box B, the seat 26 is The notch 54 and the upper notch 55 of the rail 27 coincide as shown in FIGS. The protrusion 53 is fitted. Therefore, when the support plate 28 is in the normal position, the side surface of the notch 54 of the seat base 26 comes into contact with the protrusion 53, and in this state, the main body of the fixing device cannot be pulled out from the set position. And claw 20, guide plate 2
1. In order to retract the ejection rollers 22 and 23 from the rear of the rollers 18 and 19 and release the paper ejection path behind the rollers 18 and 19, the support plate 28 is tilted around the shaft 42 as described above. The protrusion 53 of the support plate 28 escapes from the cutouts 54, 55, thereby making it possible to pull out the fixing device body part from the set position. On the other hand, when the main body of the fixing device is subsequently pushed into the set position, if it does not return to the set position, the two notches 54,
55 do not match, in that case, the protrusion 53 will only hit the upper end of the bent portion 26' and will not fall into the notch 54 of the seat 26, and the support plate 28 will be moved from the temporary position to 20, 21, 22, 23. Each member cannot be returned to its normal position constituting the paper ejection path. In other words, the means 53, 54, and 55 cannot pull out the fixing device main body from the set position while the separating claw 20 remains in contact with the roller 18 (if it is pulled out, the roller 18 will be damaged by the claw 20, In addition, it is ensured that the entire fixing device cannot be set to an operable state unless the fixing device main body is returned to the set position, and erroneous operation can be prevented.
Incidentally, contrary to the illustrated example, it is also possible to provide a protrusion on the base 26 and provide a recess in the support plate 28 to fit the protrusion, instead of the means 53 and 54 in the figure.

Next, the roller drive mechanism will be explained. 8th
9 are views of the roller drive mechanism viewed from the back of the paper of FIG. 1. In each figure, 18
is a gear fixed to the shaft of the fixing roller 18.
Further, 56 is a gear rotatably supported at an immovable position within the copying machine main body box B, and a sprocket 57 is integrally fixed to this gear 56. A chain 58 that transmits the rotational driving force from the main motor M is hung on the sprocket 57, and the gear 56 is thereby rotationally driven. The rotation of gear 56 is transmitted to gear 18 via idler gears 59 and 60. That is, gear 56 is gear 59
The gear 59 meshes with the gear 60,
The gear 60 is then meshed with the gear 18.

The motor M also drives the drum 1, mirrors 3 and 4, rollers 13 and 15, and belt 17 via a power transmission mechanism such as a chain, sprocket, clutch, and gear train.

Now, the gear 60 is rotatably supported by a shaft 62 implanted in an arm 63 that can swing around a shaft 61 supported at an immovable position within the copying machine body box B. Therefore, even if the fixing device main body portion is pulled out from the copying machine main body, the gears 59 and 60 remain on the copying machine main body side. A gear 59 is also rotatably supported on the shaft 61. In the state shown in FIG. 8, that is, when the support plate 28 is in the normal position, the arm 63 has the ability to rotate counterclockwise around the shaft 61 due to gravity, and this causes the gear 60 to move into the gear. meshes with 18.

On the other hand, 64 is an arm that can swing around a shaft 65 that is supported at an immovable position inside the copying machine body box B, and one end of the arm 64 is fixed at an immovable position inside the copying machine body box B. The other end of the spring 66 is locked, thereby giving the arm 64 the ability to rotate clockwise. A pin 67 is implanted in the arm 64 at a position opposite to the locking portion of the spring 66 with respect to the shaft 65, and a pin 68 is installed on the same side of the shaft 65 as the locking portion of the spring 66. has been planted. When the support plate 28 is in the normal position, the upper side surface of the support plate 28 engages with the pin 68 to hold the arm 64 in the position shown in FIG. 8 against the elastic force of the spring 66. At this time pin 6
7 is spaced apart from the arm 63), but the support plate 2
8 to the temporary position, the pin 68 is moved to this support plate 28.
The arm 64 is then rotated clockwise by the spring 66. Then, the pin 67 comes into contact with one end of the arm 63 and pushes it, causing the arm 63 to
is rotated clockwise to separate the gear 60 from the gear 18 as shown in FIG. Note that when the arm 63 rotates clockwise within a predetermined angle range, the arm 53 hits the stopper 69 and stops rotating. (See Figure 9)
When the support plate 28 is rotated back to its normal position, the upper side surface of the support plate 28 hits and pushes the pin 68 as described above, and the arm 64 is rotated counterclockwise against the elastic force of the spring 66. Because it moves, arm 63
The gear 60 also rotates counterclockwise due to gravity, so that the gear 60 meshes with the gear 18.

Note that 70 is a manual rotation knob fixed to the shaft of the roller 18 on the opposite side to that on which the gear 18 is fixed.

Now, while the copying machine is operating, the paper P is moved to the rollers 18 and 1.
9, if it becomes stuck while being held in the box B, a known detection means will detect this and cut off the input to the motor M and the heater 18''.In this case, the front door of the box B will be opened and the Support plate 2 by operation
8 to the temporary position. As a result, the claw 20, the guide 21', and the paper ejection roller 22, which were arranged on the rear side of the rollers 18 and 19 in the paper traveling direction,
23 retreats from the paper conveyance path, and the rollers 18, 1
A free space opens up behind 9. Thus, when the operator manually rotates the knob 70, the roller 19 rotates in the direction of the arrow, and thereby the roller 18
Since the roller also rotates due to friction, the paper is delivered to the rear of the roller. And the paper can be easily removed from the large open space above. At this time, roller 1
Since the roller 9 is not separated from the roller 18, the paper is brought into contact with the roller 18 by the roller 19. Therefore, the toner image receives residual heat from the roller 18 and is fused and fixed on the paper. Also, at this time, as mentioned above, the gear 60 is separated from the gear 18, and the connection between the motor and the rollers is broken, so the roller pair 18,
19 can be manually rotated by a knob 70.

In the unlikely event that the jammed paper cannot be removed even with the above operations, or the rollers 18 and 1
When replacing, repairing, cleaning, or cleaning the guide 21, the main body of the fixing device containing the rollers 18 and 19 is pulled out from the main body of the copying machine along the guide member 27. Since it is separated from the gear 18, there is nothing that will interfere with the gear 18 when reinstalling the fuser main body by pushing it into the copying machine main body along the guide member 27 after completing this drawer and the necessary work. is easy. Then, by the above operation, the main body of the fixing device is pulled out from the set position, and the hook members 37a and 37b are manually rotated clockwise as shown in FIG. 4 to be removed from the rod 38. As shown in the figure, the upper plates 24a and 24b are manually rotated counterclockwise together with the roller 18 to open the main body of the fixing device and perform the necessary treatment. When the necessary treatment is completed, the fixing device main body portion is manually returned to the set position within the copying apparatus main body in the reverse order to the above.

Although the embodiments have been described in detail above, according to the present invention, the simple structure makes it easy to remove jams on the image support material and to clean, repair, and replace the rollers, without damaging the rollers, and in addition, the fixing device body Various useful effects can be achieved, such as eliminating the possibility of accidents such as operating the device without completely returning the parts to the set positions.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of an electrophotographic copying machine in which the fixing device of the present invention can be used, Fig. 2 is a sectional view of an embodiment of the invention, and Fig. 3 is a diagram showing the roller of the embodiment in a pressurized state. Fig. 4 is a side view of the main body part in a state where the roller pressure of the same embodiment is released;
Fig. 5 is a sectional view of the main body in the same embodiment with the upper part open, Fig. 6 is a perspective view of the main part in the same embodiment with the main body pushed into the setting position, and Fig. 7
The figure is a perspective view of the main part of the same embodiment with the main body pulled out from the setting position, and FIGS. 8 and 9 are explanatory diagrams of the roller drive mechanism. 18 is a fixing roller, 19 is a pressure roller, 20 is a separation claw, 21 is a guide plate, 22, 23 are discharge rollers, 24a, 24b are upper plates, 25a, 25b are lower plates, 26 is a pedestal, 27 is a guide rail, 28
is a support plate, 35a, 35b are shafts, 36a, 36b
is a shaft, 37a and 37b are hook members, 38 is a locking rod, 40 is an adjustment bolt, 41 is an adjustment nut,
42 is a shaft, 53 is a protrusion, and 54 and 55 are notches.

Claims (1)

[Claims for Utility Model Registration] (1) A fixing unit that is equipped with a pair of rollers that nip and convey a toner image support material, and that is integrally equipped with a fixing unit that can be pulled out from the main body of the device and a separation member that separates the support material from the rollers. The image recording apparatus has an apparatus main body and an openable/closable ejection unit, and when the ejection unit is in an open state, the fixing unit can be pulled out, and when the ejection unit is in a closed state, the fixing unit can be pulled out. . An image recording device characterized in that the unit is prevented from being pulled out. (2) The image recording apparatus according to claim 1, which has a guide means for guiding the drawer of the fixing unit.