JP3293169B2 - Belt meandering correction device for fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device of the type in which a toner image is thermally fixed on a sheet by pressing a pressure belt (endless belt) against a heating roller. The present invention relates to a belt meandering correction device for correcting the wobble.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus using a dry toner, such as an electronic copying machine or an image recording apparatus, a toner image formed on an image carrier such as a photosensitive drum is transferred onto a sheet, and the image is undecided. The sheet carrying the toner image is conveyed toward a fixing device, and in this fixing device, the toner is melted by applying heat or pressure to perform fixing.

[0003] As such a fixing device, a heating roller system is generally employed in which a sheet is nipped between a pressure roller and a heating roller to perform fixing by heat and pressure.
However, in the heating roller type fixing device, there is a problem in that when the paper is passed between both rollers and heated and pressed, the paper is wrinkled and the image is shifted.

For this reason, the same applicant as the present applicant has previously proposed a fixing device provided with a pressing mechanism for a heating roller by a pressing belt mechanism and a belt meandering correction device (filed on March 15, 1991). ).

FIG. 10 shows the structure of the fixing device. The fixing device 1 is provided in a copying machine, and includes a heating roller 2 containing a heating lamp 3 therein, a pressing belt mechanism 4 for pressing a sheet against the heating roller 2,
And a pressure plate 5 for performing a pressing action from the back surface of the pressure belt mechanism 4. A temperature sensor 9 is provided for the heating roller 2 to adjust the temperature of the heating roller 2. A transport mechanism 6 and a guide plate 7 are arranged upstream of the fixing device 1. On the other hand, on the downstream side, a peeling claw 10 and a discharge roller 8 for peeling the sheet after fixing from the heating roller 2 are arranged. The pressure belt 11 constituting the pressure belt mechanism 4 is formed as an endless belt member by coating a glass cloth with a fluororesin.

[0006] The pressure belt 11 is wound around an entrance roller 12, a driving roller 13, a tension roller 14, and a meandering correction roller 15, thereby driving the belt.
The setting of the tension and the prevention of meandering are performed. Further, upstream of the position where the paper is set on the pressure belt 11, belt end detection sensors 16 are arranged on both sides of the pressure belt 11, respectively. The belt end detection sensor 16 detects meandering of the pressure belt 11 within the normal meandering range during the fixing operation, and performs a correcting operation based on the detection signal. The tension roller 14 applies a constant tension to the pressure belt 11 by a spring 17.

The meandering correction roller 15 is a roller in which a long roller is disposed in the width direction of the pressure belt 11, and a meandering correction mechanism is disposed at each end of the roller shaft. This meandering correction mechanism includes a solenoid 18 and a link 19. The link 19 is swingable about a fulcrum 20. A solenoid 18 is connected to the base of the link 19, and a shaft 21 of the meandering correction roller 15 is connected to the other end. In this meandering correction mechanism, a solenoid 18 is driven by a detection signal output from a belt end detection sensor 16, and swings the meandering correction roller 15 in accordance with the bias of the pressure belt 11,
The position of the pressure belt 11 is corrected. In addition,
The trajectory R on which the meandering correction roller 15 swings depends on the approach roller 1
An ellipse is drawn with the center of the axis 2 and the axis of the tension roller 14 as the focal points, and the meandering correction roller 15 is swung according to the elliptical arc to constitute a guide mechanism for this roller.

[0008]

As described above, FIG.
In the fixing device shown in (1), the meandering state of the pressure belt 11 can be corrected by the meandering correction mechanism. However, since the solenoid 18 is used as the meandering correction mechanism, when the solenoid 18 is used for a long period of time, the power is reduced and the device does not operate sufficiently. As a result, there is a problem that a stable meandering correction operation cannot be performed. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to correct the belt meandering of a fixing device capable of stably correcting meandering for a long period without using a solenoid as meandering correcting means. It is to provide a device.

[0010]

According to the first aspect of the present invention,
Is (a) includes a heating roller and a pressure belt, a sheet carrying a toner image between the heating roller and the pressure belt
Performing heat and pressure to the sheet by passing the in belt meandering correction apparatus for performing snake <br/> line modification of the pressure belt of the fixing device for fixing by melting the toner, (b) pressure The belt is stretched and at least the length of each pressure belt
Is disposed so as to be freely displaceable among a plurality of rollers having a width of
At least one of which corrects the meandering of the belt by its displacement
And meandering correction roller of the present, (c) its the meandering correction roller
It is arranged corresponding to the vicinity of each end,
It is held rotatably about the fulcrum, and meandering correction
Each lower end according to the direction and amount of roller displacement
Rotation position around the corresponding fulcrum in the
First and second levers, and (d) the first lever
When the lower end moves to the first rotation position,
First meandering detection means for detecting meandering in the first direction;
(E) The lower end of the second lever moves to the second rotation position
Meandering of the pressure belt in the second direction opposite to the first direction
A second meandering detecting means for detecting the
And meandering correction according to the detection result of the second meandering detecting means.
Correct the meandering of the pressure belt by correcting the attitude of the roller.
Means for correcting the belt meandering of the fixing device.
Be prepared.

That is, according to the first aspect of the present invention,
Paper having a roller and a pressure belt and carrying a toner image
Between the heating roller and the pressure belt.
Apply heat and pressure to the paper to melt the toner
Meandering to correct meandering of pressure belt of fixing device to fix
In the correction device, a pressure belt is stretched and
Correct at least one meandering belt
Displacement near the respective ends of the rollers is first and second.
Use the lever to change the rotation to a predetermined one,
Alternatively, the second meandering detecting means detects the meander in both directions of the pressure belt.
Each row is detected individually. And these
Meandering repair according to the detection results of the first and second meandering detecting means
Correct the meandering of the pressure belt by correcting the attitude of the positive roller.
I am trying to correct.

In the belt meandering correction device of the present invention, the driving force from the driving source (motor) is applied to the driving force intermittent means (clutch).
Is transmitted intermittently to the roller of the meandering correction means via the
A stable meandering correction operation is performed over a long period of time.

[0013]

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

FIG. 1 shows a fixing device 3 according to an embodiment of the present invention.
1 shows a configuration viewed from the side, and FIGS. 2 and 3 each show a configuration viewed from the direction of arrows AA in FIG.

The fixing device 31 has a heating lamp 3 inside.
3, a pressing belt mechanism 35 for pressing the conveyed sheet 34 against the heating roller 32, and a pressing mechanism for performing a pressing action from the back surface of the pressing belt mechanism 35. It is constituted by a pressure plate 36.

A transport mechanism 37 and a guide plate 38 are arranged on the upstream side of the fixing device 31, and a discharge roller (not shown) is arranged on the downstream side. The heating roller 3
2, a temperature sensor (thermistor) 39 is provided. A temperature control circuit (not shown) adjusts the temperature of the heating roller 32 based on the temperature detected by the temperature sensor 39. In the vicinity of the heating roller 32,
A peeling claw 40 for peeling the sheet after fixing from the heating roller 32 is provided.

The pressing belt 41 constituting the pressing belt mechanism 35 is formed by coating a glass cloth with a fluororesin to form an endless belt member. The pressure belt 41 is wound around the approach roller 42, the drive roller 43, and the meandering correction roller 44, so that the driving of the pressure belt 41 and the meandering correction are performed. Further, on the upstream side of the pressure belt 41 at the position where the paper 34 enters, on both sides of the pressure belt 41, belt end detection sensors 45a and 45b are arranged at positions separated from the pressure belt 41, respectively. . The belt end detection sensors 45a and 45b detect meandering of the pressure belt 41 within the normal meandering range during the fixing operation, and perform a correcting operation based on the detection signal.

The belt end detection sensors 45a and 45b are arranged on frames 46a and 46b, respectively. On the frames 46a and 46b, there are further provided levers 47a and 4b.
7b is arranged. The levers 47a and 47b are rotatable around fulcrums 48a and 48b, respectively. Rollers 49a, 49b are attached to one ends of the levers 47a, 47b, respectively. These rollers 4
Reference numerals 9a and 49b face the end surfaces of the pressure belt 41, respectively, and one of them is in contact with the end surface of the pressure belt 41. The other end of each of the levers 47a and 47b is
They respectively face the belt end detection sensors 45a and 45b. The fulcrum 48a of each of the levers 47a and 47b,
The intermediate portion between the roller 48b and the rollers 49a, 49b and the frame 46 are connected by springs 50a, 50b, and the levers 47a, 47b are respectively pressed by the elastic force of the springs 50a, 50b.
It is biased to one side. On the other hand, the stoppers 51a,
1b is provided, which allows the levers 47a, 47
b is held at an initial position along the end surface of the pressure belt 41.

On the frame 46, the abnormality detection sensor 5 is located at a position inside the belt end detection sensors 45a and 45b.
2a and 52b are provided, respectively, and these abnormality detection sensors 52a and 52b detect deviation of the pressure belt 41 over a certain value, that is, an abnormality state in the abnormality detection range B.

The meandering correction roller 44 is formed long in the width direction of the pressure belt 41, and one end of the roller shaft 44a is
As shown in FIG. 1, it is inserted into a notch groove 60b formed in a plate 60 that can swing about a fulcrum 60a. A shaft 61a is further fixed to the plate 60, and a roller (cam follower) 61 is rotatably supported on the shaft 61a. Plate 60 is spring 6
4, the roller 61 is elastically urged in the lower right direction in the figure, whereby the roller 61 is pressed against the meandering correction cam 62. The roller 61 is driven by the rotation of the meandering correction cam 62, and thereby the plate 60
, And as a result, the meandering correction roller 44 swings.

The shaft 6 of the meandering correction cam 62 has a clutch 6
5, a timing cam 66 is attached,
A changeover switch 67 serving as a changeover signal output means is provided facing the timing cam 66. Clutch 6
5 is supplied with a driving force from a motor (not shown) (fixer driving motor), and a belt end detection sensor 42 is provided.
a, 42b. The clutch 65 is turned on in response to these detection signals,
The driving force is transmitted to the meandering correction cam 62. The timing cam 66 has a semicircular large diameter portion 66a and a semicircular small diameter portion 66b. The changeover switch 67 is turned on when the large diameter portion 66a is detected, and outputs, for example, a "1" signal as a switching end signal. On the other hand, when the small diameter portion 66b is detected, the changeover switch 67 is turned off and outputs a "0" signal as the switching end signal. It is supposed to.

FIG. 3 shows that the pressure belt 41 meanders in one direction,
The state when the belt end detection sensor 45a detects this is shown. That is, when the roller 49a is pressed by one end of the pressure belt 41, the lever 47a starts rotating clockwise in the figure around the fulcrum 48a against the elastic force of the spring 50a. When the lever 47a rotates by a predetermined amount, the other end of the lever 47a shields the belt end detection sensor 45a from light, and the belt end detection sensor 45a detects this. When the belt end detection sensor 45a detects, the clutch 65 is turned on. As a result, the rotational force of a fixing device drive motor (not shown) is transmitted to the meandering correction cam 62. As a result, the meandering correction cam 62 starts rotating, and the meandering correction roller 44 starts to swing via the plate 60. Further, when the meandering correction cam 62 continues to rotate and the changeover switch 67 detects the small diameter portion 66b and outputs a "0" signal as a changeover end signal as shown in FIG. 5, the clutch 65 is turned off. As a result, the transmission of the driving force to the meandering correction cam 62 is interrupted, and the swinging operation of the meandering correction roller 44 ends.
As a result, the pressure belt 41 starts to move to the opposite side.

In this state, when the pressure belt 41 moves to the opposite side, the other end of the pressure belt 41 is detected by the belt end detection sensor 42b. FIG. 3 shows the state at that time.

When the pressure belt 41 moves to the opposite side, the roller 49b is pushed by the other end, and the lever 47b rotates counterclockwise in the figure around the fulcrum 48b against the elastic force of the spring 50b. I do. This lever 47
The belt end detection sensor 45b is shielded from light by the other end of the pressure belt 41, and detects the other end of the pressure belt 41. As a result, the clutch 65 is turned on again, and the torque of the fixing device drive motor (not shown) is transmitted to the meandering correction cam 62. Therefore, the meandering correction cam 62 starts to rotate again, and the meandering correction roller 44 starts to swing through the plate 60 in the opposite direction. Further, when the meandering correction cam 62 continues to rotate and the changeover switch 67 detects the large-diameter portion 66a and outputs a "1" signal as a changeover end signal as shown in FIG. 4, the clutch 65 is turned off. As a result, the transmission of the driving force to the meandering correction cam 62 is interrupted, and the swinging operation of the meandering correction roller 44 is completed. As a result, the pressing belt 41 changes its moving direction and is detected by the belt end detection sensor 45a again. And the same operation is repeated thereafter.

The belt end detection sensors 45a, 45
When b does not operate due to some abnormality, the levers 47a and 47b rotate further outward than in the above-described case. As a result, the abnormality detection sensors 52a, 52b
Detects this, receives the detection signals output from these sensors 52a and 52b, and operates the abnormality detection circuit shown in FIG. 8 and the interlock circuit shown in FIG.
The whole device stops.

The abnormality detection sensors 52a and 52b are in a normally closed state, and the relay K is connected to the interlock circuit.
1, and K2 are connected in series. When the abnormality detection sensor 52a or the abnormality detection sensor 52b operates,
When it is open, the interlock line breaks,
The power supply to the relays K1 and K2 is stopped. As a result, the relay contacts K1-A, K2-
A is in an open state, the power supply to the power supply 73 for the motor 72 and the power supply to the heater 33 are stopped, and the entire apparatus is thereby stopped.

FIG. 6 shows a configuration of a control unit for performing the belt meandering correction operation. In this control unit, C
A detection signal is supplied to the PU 70 from the belt end detection sensors 45a and 45b, and a changeover signal is supplied from the changeover switch 67. When a detection signal is supplied from the belt end detection sensors 45a and 45b, the CPU 70 outputs an ON signal to the transistor 71, thereby turning on the clutch 65 and receiving a switching end signal from the changeover switch 67. , An off signal is output to the transistor 71, thereby turning off the clutch 65. That is, when the belt end detection sensor 45a detects one end of the pressure belt 41, the transistor 7
1 to output an ON signal. As a result, the clutch 65 is turned on. Then, the output signal of the changeover switch 67 becomes “0”.
Is switched to “1”, and when this “1” is supplied as the switching end signal, the CPU 70 outputs an off signal to the transistor 71. As a result, the clutch 65 is turned off, and the switching in the meandering direction is completed. On the other hand, when the belt end detection sensor 45b detects the other end of the pressure belt 41, it outputs an ON signal to the transistor 71. As a result, the clutch 65 is turned on. And the changeover switch 67
Is switched from “1” to “0”, and when this “0” is supplied as a switching end signal, the CPU 70
Outputs an off signal to the transistor 71. As a result, the clutch 65 is turned off, and the switching in the meandering direction is completed.

In this embodiment, the belt end detection sensor 45
a, 45b and the changeover switch 67 constitute an AND circuit. That is, when the belt end detection sensor 45a outputs a detection signal, the output signal of the changeover switch 67 is always "0". On the other hand, the belt end detection sensor 45
When b outputs the detection signal, the output signal of the changeover switch 67 is always "1". When these conditions are not satisfied, the CPU 70 does not output an ON signal to the clutch 65.

In the meandering correction apparatus of the present embodiment, the following initialization operation is performed prior to the meandering correction operation so that such a condition is satisfied during the meandering correction. That is, in order to always satisfy the operation of the AND circuit, when the printing operation is started, the clutch 65 is turned on by the printing operation signal, and thereafter, until the output signal of the changeover switch 67 is inverted, that is, the output signal of the changeover switch 67 is changed. The CPU 70 continues to output the ON signal to the clutch 65 until the output signal of the changeover switch 67 is inverted until “1” is set to “0” and “0” is set to “1”. An off signal is output to 65. afterwards,
The normal meandering correction operation is performed.

Next, the initialization operation will be described with reference to a flowchart shown in FIG.

After the printing operation is started, the CPU 70
Is performed after the clutch 65 is turned on (step S10).
0), when the changeover switch 65 is inverted from off (“0”) to on (“1”) (step S101),
That is, when the state shown in FIG. 5 is switched to the state shown in FIG. 4, if the belt end detection sensor 45a is on (step S102; Y), the clutch 65 is kept on (step S102; Y). Step S103), the belt end detection sensor 45a is off (Step S102; N), the belt end detection sensor 45b is on (Step S104; Y), and the belt end detection sensor 45b is off (step S1)
04; N), the clutch 65 is turned off (step S105), the initialization operation is completed, and the normal meandering control is performed.

After turning on the clutch 65 (step S100), the CPU 70 turns the changeover switch 65 from on ("1") to off ("0") (step S106). When the state shown in FIG. 5 is switched to the state shown in FIG. 5, the belt end detection sensor 45b is turned on (step S107;
In Y), the clutch 65 is kept on (step S10).
8), when the belt end detection sensor 45b is off (step S107; N), when the belt end detection sensor 45a is on (step S109; Y),
And when the belt end detection sensor 45a is off (step S109; N), the clutch 65
Is turned off (step S110), the initialization operation is completed, and the ordinary meandering control is performed.

As described above, according to the belt meandering correcting device of this embodiment, the initialization operation and the normal meandering correcting operation are performed via the clutch 65 without using a solenoid. Therefore, the meandering correction roller 44 is reliably driven, and a stable meandering correction operation can be performed for a long period of time.

[0034]

As described above, according to the first aspect of the present invention , the displacement of both ends of the meandering correction roller is controlled by
The first and second levers are used to change the rotation to a predetermined value.
Pressure bell by the first or second meandering detecting means corresponding to
To detect the meandering in both directions separately.
Output operation is stable and detection reliability can be improved.
To perform a stable meandering correction operation over a long period of time
Can be.

[Brief description of the drawings]

FIG. 1 is a side view illustrating a main configuration of a belt meandering correction device according to an embodiment of the present invention.

FIG. 2 is a plan view for describing an operation at the time of correcting meandering in one direction, as viewed from the direction of arrows AA in FIG. 1;

FIG. 3 is a plan view for explaining an operation at the time of correcting meandering in a direction opposite to FIG. 2 when viewed from the direction of arrows AA in FIG. 1;

FIG. 4 is a perspective view for explaining an operation of a meandering correction roller swinging mechanism corresponding to the operation of FIG. 3;

FIG. 5 is a perspective view for explaining the operation of the meandering correction roller swinging mechanism corresponding to the operation of FIG. 2;

FIG. 6 is a circuit configuration diagram of a control unit that performs a meandering correction operation.

FIG. 7 is a flowchart for explaining an initialization operation by a control unit in FIG. 6;

FIG. 8 is a configuration diagram of an abnormality detection circuit.

FIG. 9 is a configuration diagram of an interlock circuit.

FIG. 10 is a cross-sectional view illustrating a configuration of a belt meandering correction device proposed earlier.

[Explanation of symbols]

31: fixing device, 32: heating roller, 34: paper, 44
... meandering correction roller, 45a, 45b ... belt end detection sensor, 60 ... plate, 62 ... meandering correction cam, 65 ... clutch, 66 ... timing cam, 67 ... changeover switch,
70 ... CPU (Central Processing Unit)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-287578 (JP, A) JP-A-2-183279 (JP, A) JP-A-2-210480 (JP, A) JP-A-60-1985 178111 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G05D 3/12 305

Claims (1)

(57) [Claims] 1. A heating roller and a pressure belt having a heating roller and a pressure belt.
A heating and pressurizing operation on the sheet by passing the paper through the gap, and a meandering correction device for correcting the meandering of the pressure belt of the fixing device for melting and fixing the toner, wherein the pressure belt is tensioned. At least each pressurized bell
Of a plurality of rollers having a width of
And the displacement corrects the meandering of the belt.
At least one meandering correction roller is arranged corresponding to the vicinity of each end of the meandering correction roller.
And are rotatably held around predetermined fulcrums.
The direction and amount of displacement of the meandering correction roller
Center on the corresponding fulcrum at each lower end according to
First and second levers for changing the rotational position
And the lower end of the first lever moves to a first rotational position.
Detecting the meandering of the pressure belt in the first direction.
And the lower end of the second lever is moved to a second rotational position.
The pressure belt has a snake in a second direction opposite to the first direction.
A second meandering detecting means for detecting a row, and a detection result obtained by the first and second meandering detecting means.
Pressurizing by correcting the posture of the meandering correction roller
Belt meandering correction apparatus of the fixing device characterized by comprising a meandering correction means for correcting a meandering of the belt.