JPH02158785A - Image forming device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an image forming apparatus in which a sheet to be fixed after fixing is separated from a fixing roller by a separating claw.

[Conventional technology]

In image forming devices such as copying machines, facsimiles, and printers, which form a toner image on a sheet to be fixed such as transfer paper and fix it, the transfer paper is passed between a pair of rollers. The toner image is heated and fixed by a roller having a heat source.

During such heat fixing, the transfer paper surface on the side with the toner image tends to stick to the roller with the heat source due to the adhesiveness of the toner image, so the separating claw should not be brought into contact with the roller. Then, the leading edge of the transfer paper is scooped up and separated from the surface of the paper. However, even if the separation claws are brought into contact in this way, there are cases where the transfer paper wraps around the circumference of the roller due to poor separation, or the leading edge of the transfer paper gets caught at the separation part, causing a jam in the transfer paper. There is.

Conventionally, the separation claw is a separation claw unit, and this is removed from the fixing unit to remove the jammed transfer paper from the fixing roller.

[Problem to be solved by the invention]

In the past, the separation claw unit had to be removed.

After removing the jammed paper, it is very troublesome to install it, and there is a problem that sometimes the tip of the separating claw damages the surface of the fixing roller when removing and installing it. Therefore, efforts have been made to improve the life cycle of the roller by applying carbon treatment to the surface of the fixing roller to form a hardened layer and making the surface less likely to be damaged, but this increases the cost of the roller. Ancillary problems have also arisen.

An object of the present invention is to provide a separating claw in a discharge unit that can be opened and closed, and to move the separating claw toward and away from the fixing roller by opening and closing the unit. An object of the present invention is to provide an image forming apparatus in which maintenance and inspection of parts, etc. can be easily performed.

[Means to solve the problem]

In order to achieve the above object, the present invention provides an image forming apparatus according to the present invention, and a fixing roller for fixing a toner image on a fixing sheet.

a separation claw for separating the sheet to be fixed after fixing from the fixing roller while in contact with the fixing roller;

A discharge unit is provided with a swingable separation claw and is displaceable between a closed position for discharging and conveying separated sheets to be fixed and an open position for opening a discharge and conveyance path for the sheet to be fixed; and an opening of the discharge unit. At this initial stage, the separation claw is rotated in a direction to separate from the fixing roller in conjunction with the opening, and when the ejection unit is closed, from just before closing until the end of closing, the separation claw is and an interlocking means for rotating the separating claw in a direction to bring it into contact with the fixing roller in conjunction with the fixing roller.

〔Example〕

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

In FIG. 1, an upper unit 3 is attached to a main body frame 1 of the image forming apparatus via a pivot 2 so as to be rotatably openable and closable. The upper unit 3 is provided with a photosensitive drum (not shown) and copying process devices such as a charging device, an exposure device, a developing device, and a cleaning device arranged around the photosensitive drum. The fixing unit 5 is capable of sliding on the main body frame 1 in a direction perpendicular to the paper plane of FIG. 1, and is locked at the position shown in the figure.

When the upper unit 3 is rotated clockwise in the figure around the pivot 2, the lower part of the photosensitive drum and the transfer paper conveyance path from the paper feed section (not shown) to the fixing unit 5 are opened. At this time, the fixing unit 5 is left on the side of the apparatus main body.In the image forming apparatus of this example, the upper unit is opened upward, making it a so-called clamshell image forming apparatus.

The fixing unit 5 includes a fixing roller 6 having an internal heat source,
It is equipped with a pressure roller 7 that comes into pressure contact with this.

After the transfer paper 8, which is an example of the sheet to be fixed, has been transferred, it is sent between the rollers 6, 7. When the toner image T passes between the two rollers, the toner image T on the transfer paper is heated and fixed.

As shown in FIG. 2, unit side plates 11 (the other is not shown) on both sides of a discharge unit 10 are attached to the unit side plates 4 of the upper unit 3 via a pivot 9, and the discharge unit 10 is mounted around the pivot 9. It can be opened and closed by swinging. Note that FIG. 2 is a view of the discharge unit 10 of FIG. 1 viewed from above.

In FIGS. 1 and 2, a support member 14 is fixedly attached to the stem member 13 that is fixedly suspended horizontally between both unit side plates 11. Normally, a plurality of separation claws 16 are provided, to which the separation claw 16 is pivotally attached. It only shows. A support bracket 17 is also fixedly attached to the stem member 13, and a lock member 19 is pivotally attached to the support bracket 17 by a pivot shaft 18.

Pin 21 and lock member 1 implanted in support bracket 17
A tension spring 23 is inserted between the shaft 22 inserted through the
Further, a tension spring 24 is provided between the shaft 22 and the separation claw 16.
are hung on each.

A pin 4b is attached to the right side extension 4a (FIG. 3) of the unit side plate 4 of the upper unit 3 in FIG. is adapted to be locked in the closed position.

Next, to explain the operation of the embodiment of the present invention, as shown in FIG. 1, the locking member 19 has a tendency to rotate counterclockwise around the pivot shaft 18 due to the elasticity of the spring 23. However, this natural rotation is prevented by the locking member 19 itself coming into contact with a stopper pin 28 provided on the side of the support bracket 17.

In this state, the locking member 19 engages with the pin 4b, and the ejection unit 10 is locked in the illustrated closed position. In this locked position, the separation claw 16 provided on the side of the unit 10 comes into contact with the fixing roller 6 due to the action of the spring 24, and the transfer paper 8 comes out while remaining in contact with the surface of the roller 6. When done, scoop up the tip and separate.

The separated transfer paper is further moved by the separation claw 16 to a pair of ejection rollers 25 provided in the ejection unit 10,
26, and then held between two rollers, and ejected and conveyed toward, for example, an ejection tray (not shown) outside the machine.

The discharge unit 10 is normally held in a closed position that achieves such a discharge conveyance function, and in this held state,
The separation claw 16 also performs its original function by contacting the fixing roller 6.

Here, if a separation failure occurs and the transfer paper 8 wraps around the circumferential surface of the fixing roller 6, or the leading edge of the transfer paper gets caught on the separation claw 16, or the transfer paper 8 is moved from the separated position to the ejection roller. 25. In order to take out the transfer paper in the transfer paper ejection direction due to a jam occurring in the transfer paper up to point 26, the ejection unit 10 itself should be rotated around the axis 9 in the clockwise direction shown in FIG. rotationally displaced in the direction.

Then, the locking member 1 is relatively moved by the immovable pin 4b.
9 will be rotated clockwise around the pivot 18. This rotation is performed against the tensioning elasticity of the spring 23 until the pin 21, the pivot 18, and the shaft 22 are each in a colinear position. And axis 2
2 beyond its collinear position, the spring 23 becomes compressed and reaches the position shown in FIG. 3, where it is stopped by the stopper pin 28, preventing further rotation. While the locking member 19 rotates to such a position,
The locking member 19 is removed from the pin 4b.

In this way, when the spring 23 is at the right position in FIG.
9 is given the habit of rotating counterclockwise, and when in the left position, the locking member 19 is given the habit of rotating clockwise. Such a spring is also called a central thought spring.

FIG. 4 shows the movement of the locking member 19, and shows the arcuate trajectory A1 and the spring 2 caused by the rocking of the locking member 19 itself.
The spring is elongated by a difference d from the arcuate trajectory A2 due to the swinging of the position 3, and as a result, the direction of the rotational moment is switched at the central consideration position.

When the locking member 19 rotates around the pivot 18 from the position shown in FIG. 1 to the position shown in FIG. The separation claw 16 is rotated counterclockwise around the pivot shaft 15 via the spring 24 .

This is done at the beginning of the opening of the discharge unit 10, and eventually the separation claw 16 is linked to the opening of the discharge unit 10.
is rotated in the direction away from the fixing roller 6.

By opening the discharge unit 10 while rotating the separation claw 16 in the direction of gradually separating it from the fixing roller 6 in this manner, there is no possibility that the separation claw 16 will damage the fixing roller 6.

Normally, in this type of technology, the separating claw is kept in contact with the fixing roller when some unit is initially opened, and once the unit has been opened to a certain extent, the separating claw is completely separated from the fixing roller. However, if you do this, at the beginning of opening.

The fixing roller is easily damaged by the separation claw. In this example, it is possible to deal with such a point.

Further, if the ejection unit 10 is manually locked, it is necessary to release the lock, but in this example, simply rotating the ejection unit 10 automatically releases the locked state. That will happen.

From the initial open state shown in FIG. 3, the discharge unit 1o
It is further opened and stopped in a substantially horizontal position by suitable stop means.

In this state, the transfer paper ejection conveyance path on the downstream side of the fixing section is opened, making it easier to remove jammed transfer paper and perform maintenance and inspection of the fixing section and the like. In this way, the discharge unit 10 is movable between a closed position where the separated transfer paper is discharged and conveyed, and an open position where the discharge and conveyance path is opened.

Note that even when the fixing unit 5 is slid in the direction perpendicular to the paper surface of FIG. It is best to prevent this.

Here, when the opened discharge unit 10 is rotated counterclockwise to close it, the locking member 19 is in a position where it can engage with the pin 4b, as shown in FIG. 3, just before closing. placed in

Furthermore, when the ejection unit 10 is closed, the locking member 19
is engaged with the pin 4b, and when the ejection unit is further closed in this state, the locking member 19 is relatively locked by the pin 4b.
is pushed counterclockwise around pivot 18 and, after passing the central thinking position, is stopped by stop pin 28, as shown in FIG. In this state, the discharge unit 10 is locked in the closed position via the locking member 19 under the action of the tensioning force of the spring 23. In this way, the ejection unit 10 can be removed by simply rotating it into the closed position.
It is set to lock automatically.

On the other hand, when the locking member 19 rotates counterclockwise, the spring 24 shown in FIG. 3 stretches and draws the separation claw 16.
Rotate the separation claw 16 clockwise around the pivot 15.

That is, the separation claw 16 approaches the fixing roller 6 while rotating clockwise, and when the discharge unit 10 is closed, the separation claw 16 touches the circumferential surface of the fixing roller 6 as shown in FIG. come into contact with

Now, if the separation claw 16 were to come into contact with the fixing roller 6 without changing its position when the discharge unit 10 is closed, the shock caused by the closure and the shock caused by the locking action of the locking member 19, etc. Although the separation claw 16 easily damages the surface of the fixing roller 6, in this example,
This can be prevented or reduced. Further, instead of the tip 16a of the separating claw 16 biting into the fixing roller 6 as shown in FIG. Since they are in contact with each other, it is possible to prevent the surface of the fixing roller from being damaged.

Now, move the circumferential surface of the fixing roller 6 to the first position as shown in FIG.
When the spring 24 is in a contracted state, the separation claw 16 does not move blindly, so it is brought into proper contact with the circumferential surface of the fixing roller located in the second quadrant. be able to.

If the position of the separating claw 16 is not determined and the separating claw comes into contact with the circumferential surface of the fixing roller located in the 1st quadrant, for example, when the fixing roller 6 rotates, the leading end 1 of the separating claw
Since the fixing roller 6a has a tendency to bite into the fixing roller, chattering may occur at the tip thereof, which may seriously damage the fixing roller. In this example, such a situation is prevented.

The pin 4b, the locking member 192, the springs 23 and 24, etc. rotate the separating claw in the direction of separating the fixing roller from the fixing roller in conjunction with the opening of the discharge unit at this initial stage. .

This is an example of an interlocking means that rotates the separation claw in a direction to bring it into contact with the fixing roller in conjunction with the closing of the discharge unit, from just before the closing until the end of the closing. In this example.

The separation claws 16 are brought into contact and separated in conjunction with the movement of the locking member 19.

In FIG. 1, when the upper unit 3 is rotated clockwise around the pivot shaft 2 with the discharge unit 10 closed, the separation claw 16 is displaced in the direction of arrow a, and the fixing roller 6 It will be m distance from This makes it possible to take out the transfer paper from the paper feed side when the transfer paper wraps around the fixing roller 6 or gets caught by the separation claw.

FIG. 5 shows another embodiment of the invention; in this description, the same reference numerals are used for parts that perform similar functions as in the previous embodiment.

A description of this function will be omitted.

In the figure, a separation claw 16' is swingably supported on a pivot shaft 15 attached to a support member 14, and a torsion coil spring 30 is wound around the pivot shaft 15, one end of which is attached to the support member 14.
3, and the other end is in contact with a stopper plate 31 fixed to the fixing unit 5 when the discharge unit 10' is closed.

On the other hand, the upper base end of a spring 32, which is a wire bent into the shape shown in FIG. Facing the notch 31a of the stopper plate 31, the separation claw 16
' is pushed in and brought into contact with the fixing roller 6.

Here, in FIG. 5, the ejection unit 10' is placed in the closed position to achieve the function of ejecting and transporting the transfer paper after fixing.
When rotated in the direction of opening, the pin 4b relatively pushes the locking member 19 clockwise around the pivot 18, as in the previous embodiment.

Finally, the locking member 19 is placed in the position shown in FIG.
That is, it rotates to a position where it is stopped by the stopper pin 28, and during this period the locking member 19 is removed from the pin 4b.

FIG. 6 shows a state in which the discharge unit 10' is in the middle of being opened;
At this earlier opening stage, the separation pawl 16', hitherto under the action of the spring 32, is now turned counterclockwise about the pivot 15 under the action of the torsion coil spring 30. As a result, the separation claw 16' rotates in the direction away from the fixing roller 6, and the discharge unit 10' rotates in the opening direction. Therefore, during this opening, damage to the surface of the fixing roller 6 by the claw 16' can be prevented or reduced.

On the other hand, when the ejection unit l-10' opened in a substantially horizontal state is rotated in the closing direction, the locking member 19 shown in FIG. 6 engages with the pin 4b when it is about to close. 4b relative to each other around the pivot 18 in a counterclockwise direction.

Then, with the locking member 19 being stopped by the stopper pin 28, as shown in FIG.
0' is locked in the fully closed position. On the other hand, until this closing is completed, the upright part 16'a of the separating claw 16' shown in FIG. The pawl 16' is rotated clockwise around the pivot 15, and the ejection unit 1
It comes into contact with the fixing roller 6 in the closed state of 0'. On the other hand, the spring 30 comes into contact with the stopper plate 31, and this spring 3
0 has no effect on the separating claw 16'.

The spring 30 rotates the separating claw 16' in a direction away from the fixing roller, and the spring 32 rotates it in a direction to bring it into contact with the fixing roller, and each spring has a role to play. .

Also in this embodiment, the separating claw 16' gradually rotates in the direction approaching the fixing roller 6 in conjunction with the closing of the discharge unit 10', and when the closing is completed, the separating claw 16' moves toward the fixing roller 6.
, so there is no risk of the separation claw damaging the surface of the fixing roller. Also, the discharge unit 10
Similarly, there is no risk of damaging the fixing roller when opening . In this embodiment as well, the upper unit 3 can be rotated and opened around the pivot shaft 2 (Fig. 1), and even when this is opened, the separation claw 16' is moved in the direction of the arrow a (Fig. 1). The fixing roller 6 moves away from the fixing roller 6. Therefore, when the transfer paper becomes wrapped around the fixing roller 6, the transfer paper can be taken out in the paper feeding direction without resistance.

In the present invention, in addition to the heat fixing method, the roller 6.
The present invention can also be applied to an image forming apparatus using a pressure fixing method in which the elements 7 and 7 are simply pressed together.

〔Effect of the invention〕

According to the configuration of the present invention, when the ejection unit is opened, the separation claw gradually rotates in a direction away from the fixing roller, and when the discharge unit is closed, the separation claw gradually rotates in a direction in which it comes into contact with the fixing roller. Therefore, the separating claw does not impact the fixing roller, and there is no possibility that the separating claw will damage the surface of the fixing roller. Then, jam removal, maintenance inspection of the fixing section and the ejection unit section, etc. can be easily performed without worrying about such points.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of an embodiment of the present invention, Figure 2 is a top view of the discharge unit of the same embodiment, Figure 3 is a diagram showing the initial open state of the discharge unit, and Figure 4 is a lock. Diagrams for explaining the movement of members, Figure 5 is a configuration diagram of another embodiment, and Figure 6 is a diagram for explaining the movement of members.
This figure shows the initial open state of the ejection unit in another embodiment of the same as the above, and FIG. 7 is a diagram showing the separation claw rotation biasing component of the other embodiment of the same. 6... Fixing roller 10.10'... Discharge unit 16.16'... Separation claw agent Patent attorney Nori Hoshino Fumitsu? Mouth/6' Crow

Claims (1)

[Scope of Claims] A fixing roller for fixing a toner image on a sheet to be fixed; a separation claw for separating the sheet to be fixed from the fixing roller after fixing while in contact with the fixing roller; A discharge unit is provided with a swingable claw and is movable between a closed position for discharging and transporting separated sheets to be fixed and an open position for opening a discharge and conveyance path for the sheets to be fixed; At this initial stage, the separation claw is rotated in a direction to separate from the fixing roller in conjunction with the opening, and when the ejection unit is closed, from just before closing until the end of closing, An image forming apparatus comprising an interlocking means for interlockingly rotating a separation claw in a direction to bring the separation claw into contact with a fixing roller.