JPS5858575A - Fixing device - Google Patents

Abstract

PURPOSE:To relax the shock for press-fixing or stop and extend the life of an electromagnetic brake, by controlling the speed of the contacting and separating operations between two rollers to an optimum value in accordance with the moving position of the second roller in an electrophotographic device or the like. CONSTITUTION:When an electromagnetic brake 16 is released to rotated a motor 13. A spring unit 7 is moved in the direction of an arrow A through a belt 14 in accordance with the rotation of a pole screw shaft 9, and a pressure roller 6 presses upward one end of an arm 4, and a back-up roller 3 is brought into contact with a fixing roller 1. The condition and the state of the contact and separation between the rollers 3 and 1 are detected by a poentiometer 11 fixed to one end of the pole screw shaft 9. The number of revolution of the motor is controlled by an encoder 18 fixed to the shaft of the motor 13, and the motor is decelerated just before the contact of the roller 3 to the fixing roller 1 to relax the shock for press-fixing or stop, and thus, the occurrence of ruck and deviation of a form which may be generated for press-fixing is prevented, and the slip of the electromagnetic brake 16 is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fixing device used in a toner image forming device such as an electrophotographic device. 1#!
7 y 7'' A method has been used in which a cam is brought into contact with an arm that supports the row 2 axially, and the cam is rotated to press the knock-up row 2 against a heated fixing roller.

However, in such conventional devices, in some cases such as a power outage, most of the devices have a mechanism that stops in the state where the two nitrogen pairs are pressed together, and in this case, the heated fixing roller Damage to the toner image carrier (hereinafter referred to simply as paper) due to 2 (No. 10-2), or permanent deformation of the elastic body formed on the P, C, F rollers (No. 20-2). This may lead to other inconveniences. In order to avoid such a situation, attempts have been made to add a means to forcibly release the low 2 to O pressure contact in the event of an emergency at 0 tuJ, but this means has a complicated mechanism and is prone to failure.
It is also a factor in increasing costs, and no effective method has yet been found.

One purpose of the present invention is to solve the above-mentioned drawbacks of the conventional device, and by using a relatively simple configuration, it is possible to prevent two One of the other purposes is to make it possible to reliably separate the rollers, and one of the other purposes is to press or separate the two rows 2 during normal operation according to the movement position of the 20th roller. By controlling the pressure to the optimum value, the crimping machine softens the pressure when stopping, and at the same time prevents paper wrinkles and misalignment that may occur during crimping.
The present invention provides a fixing device that can reduce wear on an electromagnetic brake and extend its life. The gist of the present invention is as follows: two pairs of rows that sandwich an enlarged toner image support and fix the toner image on the support; a driving means for moving the pair of rollers toward and away from each other; and rotation of the driving means. and a means for detecting the position of the row 2.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows the overall configuration of an embodiment of the present invention, in which 1 is a fixing roller rotatably attached to and supported by a fixed side plate (not shown), and also rotated by a motor (not shown). While being moved, there is a heater 2t-A inside that serves as a heat source.
It is equipped.

The member shown as being in contact with the fixing roller l by forming the latch f portion according to the broken line in the figure is the backup row 23)
, this row 23 is rotatably supported by the arm 4. The arm 4 is rotatably supported at one end by a support shaft 5 provided on a fixed side plate (not shown), and the rotation of the arm 4 with respect to the support shaft 5 is The fixing roller 1 is provided so as to press the above-mentioned roller glow 23 against the fixing roller 1 and to separate it from the fixing roller 1.

When the row 23 is pressed by the row 1, it rotates along with the row 1 due to frictional force.

It should be noted that the arm 4 and the coil spring units described later are arranged in pairs to support the inner ends of the shafts of the packa and f-row 23, respectively, but for convenience of explanation, they will also be used in the following description. It is not stated that each pair is provided unless it is particularly necessary.

6 is a pressure roller), which engages with the cough arm at the other end (the left end of rA) opposite to the center of rotation of the arm 40 at one end as shown in the figure, and is connected to the cough arm from the coil sgering unit described later. Under force (elastic force), pack aglow A/31
``Direction of pressing against fixing roll 1 (clockwise direction in the figure)
The arm 4 is configured to apply a rotational force to the arm 4. 7 is a coil spring unit with a built-in compression spring. It is something that gives power. The pair of coil steering units 't, t, respectively disposed corresponding to the inner ends of the shaft of the 8-company backup row 23, are held together by pressurizing rods supported at both ends, and a mail nut is mounted in the middle. is fixed non-rotationally. 9 screwed into the I-lu nut? - Renezo shaft, 10 is a support member fixed to a fixed side plate (not shown); - The threaded shaft 9 is supported so as to be rotatable around the axis but not movable in the axial direction. And this? - the male nut screwed onto the threaded shaft 9;
Therefore, the pressure rod 8 and the coil spring unit, which are integral with this, and the door are l
Since the rotation of the -Lunezo shaft 9-pO is regulated, the I-Lunezo shaft 9 moves in the axial direction on the shaft 9 in a non-rotational manner as the I-Lune screw shaft 9 rotates.

What about 11? - arranged and fixed on one end side of the threaded shaft 9; /Detect the rotation angle of the multiple screw shaft 9 with a high tension meter. 12 is a timing belt assembled on the same end side of the L-Runezo shaft 9, and 13 is a motor for driving a timing pel (141), which is attached to the support member 10. 15 is a timing pulley fixed to the output shaft of the motor 13; 16 is an electromagnetic brake disposed and fixed coaxially with the timing belt 15 and the axis of the motor 13; 14 is a timing belt that is connected between the timing belt 12 and the timing gear 9150; It is stretched.

A rotary encoder 18 is fixed to a shaft in the opposite direction to the output shaft of the motor 13, and detects the same rotation speed of the motor 13.

FIG. 2 shows details of the pressurizing mechanism. Coils/
A compressed ring 62 is compressed to a preset compression amount and housed in the ring 5-2 door O cylindrical frame 61. One end of this spring 62 is a coil!
The ring is in contact with the 7-run no. 64 of the door, and the other end is in contact with the 72-in 5771 of the pressure shaft 20 that supports the pressure Q-26 on the top.

In addition, the lower part of the pressure shaft 20 is Sgeling Uni, and the lower part of the door is
1,1 is fitted and supported in a slidable relationship in the axial direction with respect to the 1,1 groove 64, and on the other hand, the 7 gear 71 provided on the upper part of the pressure shaft 20 allows the packer and grooves 8 to contact the fixing roller l. It is stored in contact with the 7-tension surface 63 of the coil spring unit 7 until then. 2
Reference numeral 1 denotes a bottle that slides in contact with the side surface of the support member 10, and when the pressure rod 8, which supports the coil steering unit 7 at both ends, moves in the axial direction of the male screw shaft 9, the bottle (8 ) Acts to prevent rollover. This bottle 21 is the pressure rod 8
Provide one or more. Note that the support member 10 is fixed to a not-shown strap plate.

Next, the operation will be explained. If the electromagnetic brake 16 is released by a control circuit (not shown) that controls the rotational drive of the motor 13, and the motor 13 starts to rotate at the same time, then...
The synchronous driving force of the rotor 13 is transmitted to the main screw shaft 9 via the tie-setting roller 15, the timing belt 14, and the tie-setting roller 12, causing the male screw shaft 9 to rotate in a predetermined direction. The male nut 19 engaged with the male screw shaft 9 moves linearly in the direction of the arrow M along the male screw shaft 9. Therefore, the pressure rod 8 to which the ball nut 19 is fixed and the nine coil spring units 7 provided at both ends of the pressure rod 8 also move in the A direction together with the ball hole 19. With this movement, the pressure roller 6 supported by the unit 7 pushes up one end of the arm 4, and the back roller 3 supported by the arm 4 pushes up the fixing roller l.
move upward to come into contact with.

on the other hand? - The input shaft of the potentiometer 11 fixed to one end of the threaded shaft 9 rotates during the above operation.

Note that the potentiometer used here is preferably a multi-rotation type that can accurately detect the rotation angle when the input shaft rotates several times at a tension of 1.

Therefore, the output signal of the potentiometer and m-luna, t19
Since the positions on the screw shaft 9 have a certain correlation, the rotation angle of the arm 40, that is, Pa, Kua, Glow 2
3 is in a position where it is in contact with the fixing roller l, or is apart and at what distance is 4
The tension can be accurately determined from the output of the meter 11.

From the above, by inputting the output signal of the 94-tary encoder 18 fixed to the shaft of the motor 13 to the control circuit, and simultaneously inputting the output signal from the potentiometer 11 to the control circuit, the Quack! low 23
It becomes possible to control the rotation speed of the motor 13 so that the optimum motor rotation speed can be obtained in accordance with the position of the press and the state of the crimping or releasing operation.

The rotation speed control of the motor 13 will be explained in detail below.

When the fixing device is in a standby state without performing a fixing operation (hereinafter referred to as state 1), - Blue, Kur,! The roller 23 is sufficiently separated from the fixing roller 1 and is in the next position, and the paper on which the toner image has been formed is moved away from the fixing roller 4 while keeping the printing press m in contact with the back roller 3. In this case, the coil sgelling unit 7 is a built-in compression coil sgelling 6.
In order to prevent the elastic force from being transmitted to the back roller 3 via the arm 4, the bevel of the screw shaft 9 shown in FIG. Pressure shaft 2007 against which one end of the shilling 62 abuts
The run/71 is in contact with the end face 63 of the coil steering unit.

Next, when a toner image is formed on the paper and should be fixed, a signal to start fixing is input to the control circuit, and in response to this, signal 1fi output from the control circuit causes the motor 1 to be fixed.
3 is activated, the electromagnetic brake 16 is released at the same time, the I-L screw shaft 9 rotates and the pressure rod 8 moves in the direction of the arrow from the standby state together with the I-L screw shaft 9. ), where the pressure row 26t - 72 of the provided shaft 20
The force of the spring 62 that biased the arm 71 upward is applied to the arm 4 through the Karo pressure rod 76 as the pressure rod 8 moves.
, one end of the arm 4 is pushed up and the /4 pull-up row 23 approaches the fixing roller l, but the coil sedge ring 62 is still in the 10-shaped embroidery until the compression wire row 23 touches the fixing roller IK. It is in the same state as. And Mo / 13 OIg1 rotation number Fi pa.

Immediately before the Quaglow-y3 contacts the fixing row 21, it is decelerated and controlled 511 so that it comes into contact with the fixing row 21 at a slow speed.

That is, until just before the glow 23 contacts the fixing roller 1, the pressurizing roller 6 is raised by the rotation of the male screw shaft 9, the arm 4 is moved simultaneously, and the pack-a-lag glow t 3 O is generated. Fixing o -yl (D) Approaching is not required to be done particularly slowly except at the initial movement, so the motor 13 that rotationally drives this male screw shaft 9 may be rotated at a certain high speed, but it is also possible to Glow: 5
'342) 7. Contact and pressure bonding to fixing 0-11. As mentioned above, it is desirable to soften the Tsuku as much as possible, so 4.
Tenshi.

By detecting the amount of rotation of the 1t-screw shaft 90 using the meter 11, the position of the coil steering unit 7 was measured by the detection stand, and it was detected that the back arrow roller 23 had reached 9 just before it came into contact with the fixed roller 21. , the rotation of the motor 130 is decelerated to slow the movement of the backplane roller 23. Coil spring unit 7 in this H state
Considering the above condition, it is necessary to prepare in advance so that the O722 shifter 1 is separated from the 72mm surface 63 of the coil spring unit O cylinder frame 61 when the fixing roller f a -53 is in contact with the fixing row 21. Therefore, if the pressure rod 8 moves further in the entry direction, the pressure rod 26 will pressurize one end of the arm 4 by the paneka of the compression coil serge ring 62.

The amount of deflection of the coil steering ring 62 is a predetermined value, that is, the back aluminum row 23 with respect to the fixing row 21.
The control circuit detects an output signal of the potentiometer (IIC) that causes the pressing force to reach a predetermined value, the motor 13 stops operating, and the electromagnetic brake 16 operates to move the pressure rod 8. is controlled to stop. (Hereafter referred to as the state of ■).

In this way, the fixing roller 21 and the pack-a-glow 23 pinch the paper, and when a predetermined pressure contact force is achieved, the fixing roller 21 is rotated by a mechanism (not shown), thereby feeding the paper and toner image on its surface. to become established.

Next, the operation at the time of completion of fixing will be explained. When the predetermined fixed toner fixing operation is completed, the control circuit stops the operation of the sheet conveying device and the rotation of the fixing roller 21, and then starts the electromagnetic delay? 16 is released and the motor 13 rotates the male screw shaft in the opposite direction to the rotation direction tM.
start

Therefore, the male screw shaft 9 is also oriented in the opposite direction i! It is rotated and driven to 7'? , &-Luna) 19, the pressure rod 8 moves linearly in the opposite direction of the arrow M, and
And the backup row 230 suppression relationship is lifted. Then, the position just before the standby position is detected from the potentiometer 11O output 1d, and the rotor 13 is decelerated, slowly moves toward the standby position, and stops at the standby position. That is, the coil/ring door, which is moved in the vertical direction in FIG. 2 due to the relationship between the male screw shaft 9 and the ball nut 19, moves from 1 to 1 before and after the operation of the fixing device, and then from melon to ■ →Move to the state I, and in the state I, which is in the middle of the movement, rotate the luneno shaft 9 so that there is a gentle acceleration at the initial movement and a gentle deceleration at the stop. Since the rotation of the motor 13 is controlled, as described above, by controlling the rotation speed of the motor 13 to the optimum condition depending on the position of the pack-ag roller, the amount of slug in the electromagnetic brake 16 is reduced, and accurate There are advantages in that positioning is possible and the life of the electromagnetic lug 16 can be extended.

31ii1 schematically shows the rotation control of the motor 130 by the above control circuit. For example, to control the rotation speed of a DC motor, the input current of the motor can be controlled by the input signal fed to the control circuit according to the figure.
- Even if the screw shaft is in a freely rotatable state and the pack-a-glalow 23 is pressed against the fixing roller l, the reaction force of the In response, the coil grip unit 7 automatically descends to the lower part of the figure 2, and the pressing force is released.

In this example, the movement position of the nut is detected by a co-rotating type I tensioner attached to the male screw shaft, and a meter is used to detect the rotation angle. It goes without saying that it may be detected as Furthermore, the movement position of the nut can be known by counting the number of pulses output from the rotary encoder in front of the potentiometer.In addition, a photoelectric switch, microswitch, or other wire switch is installed before the stop position, and the operation of this switch is It is also possible to detect the motor rotation speed and switch the motor rotation speed.

Furthermore, before &l! Although the embodiments have been described using a heat fixing device, it is obvious that the present invention can also be applied to a pressure fixing device.

[Brief explanation of the drawing]

The drawings are for the purpose of illustrating embodiments of the invention.
Figure 1 is a diagram showing the outline of the configuration of the ri device, Figure 2 is a detailed diagram of the coil/ring unit y) and its surrounding configuration, and Figure 3 is a diagram showing an example of rotation control of a single threaded shaft. be. , 1... Fixing--2, 2... Heater, 3... Pa,
Kur, Glow 2.4...Arm, 5...Support shaft,
6... Pressure row 2.7... Coil screw part 2, 8... Pressure rod, 9... Gale screw shaft, 1
0--Support member, ll--Potentiometer, 12--Timing belt, 13--Motor, 1
4...Timing belt, l 5...Tie/grip/-re, 16--electromagnetic/rake, l8...Rotary encoder 19-&-lu nut, 20-...pressure shaft, 21... bottle,
61 = 11! , 62...φ coil sgering, 63...
...7 lunge surface, 64...72 angle, 71...
7 Lunges

Claims (1)

[Scope of Claims] Two pairs of rows that sandwich a toner image support and fix the toner image on the support; a driving means for moving the pair of rows toward and away from each other; and # detecting rotation of the driving means. and a means for detecting the position of the roller.