JP3012693B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus,
In particular, the present invention relates to an image forming apparatus in which the fixing unit is detachable from an image forming apparatus main body.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine,
Some fixing units are detachably attached to the main body. In this type of image forming apparatus, an electrical conduction path such as a heater in the fixing unit is generally connected by a drawer connector. Therefore, if the fixing unit is not properly mounted, the contact state of the heater contact of the drawer connector becomes unstable, and an accident such as melting of the contact due to the generation of an arc occurs. For this reason, for example, there is a device in which the fixing heater is turned off when the door is opened, but there is also a device in which the fixing heater is not turned off when the door is opened in order to shorten the startup time. Since the fixing unit is attached and detached even when the power of the copying machine is turned on, a connector for preventing generation of noise or the like is required as described in, for example, Japanese Patent Application Laid-Open No. S59-148288.

[0003]

However, in such a conventional image forming apparatus, when the fitting of the connector is incomplete, the heater contacts come into contact with and separate from the heater while the fixing heater is ON, and the arc is generated. In some cases, the contacts melted. On the other hand, the fitting length of the connector was increased to prevent poor contact.However, the gear of the fixing unit driving provided on the main body side and the gear of the fixing unit side were meshed well. In many cases, they did not go, and in that case, damage that deformed both gears occurred.

Further, in a conventional image forming apparatus in which a heater is turned off when a door is opened, arcing is performed when, for example, a serviceman attaches / detaches a fixing unit without opening the heater with the door open. Occurred.

In any case, melting by arcing has a danger of ignition in the case of a heater having a high power of several hundred watts, such as a fixing heater, and it is an important subject to surely prevent this. .

[0006]

According to an aspect of the present invention, there is provided an image forming apparatus in which a fixing unit accommodating a heater is detachably attached to the image forming apparatus main body. Supplies power to the heater
Contact for the heater on the main body side, and the fixing unit
Contour for body set detection to detect the attachment / detachment of the unit
And the main body side heater contact and the main body side
Main body connector housing to store set detection contacts
And the fixing unit is provided with
Fixing unit heater heater contact with the heater contact
Contact with the main body side set detection contact
The fixing unit side setting detection contact
Contact unit side heater contact and fixing unit
The side set detection contact is stored and the main body side connector is
Fixing side connector housing which fits with the housing,
The main body side set detection contact and the fixing
When the unit side detection contact
Only, the main body side heater contact and the fixing unit
The image forming apparatus main body through a side heater contact
Power control so that power is supplied to the heater data from
Supply control means, the main body side connector housing and
When the fixing side connector housing is fitted,
The body side heater contact and the fixing unit side heater
After the contact with the
The detection contact and the fixing detection side
Contact with the main body side connector housing.
When the fixing side connector housing separates,
The body side heater contact and the fixing unit side heater
Before the data contact comes off,
The detection contact and the fixing detection side
The contact is separated from the contact .

According to a second aspect of the present invention, the operation of the heater is performed.
After stopping, the contacts of the electromagnetic switch connected in series to the heater
It is characterized by being open .

According to a third aspect of the present invention, there is provided a fixing unit.
At the time of wearing, a fixing temperature detecting member provided in the fixing unit
After the connector of
Contact and contact for detecting the fixing unit side set
Are in contact with each other.

According to a fourth aspect of the present invention, the main body side set is provided.
The detection contact and the fixing detection side
After contact with the contact, depending on the resistance value of the thermistor
It is characterized by controlling the heater .

According to a fifth aspect of the present invention, the main body side set is provided.
The detection contact and the fixing detection side
An image forming state is set after contact with a contact .

[0011]

According to the first aspect of the present invention, the main body side set detection is performed.
Contact and fixing unit side set detection contact
The contact timing, when mounting the fixing unit slower than the connection of the heater for conductive paths, faster than the cut-off of the heater conduction path during disengagement of the fixing unit. Therefore, it is possible to prevent the fixing unit from being attached and detached while the heater is energized. Further, the connection timing of the heater connector and the connection timing of the attachment / detachment detection signal can be easily mechanically defined. Also, the heater connector is completely
The heater can be controlled while connected, and
Is reliably prevented from occurring.

According to the second aspect of the invention, the life of the contact can be increased by opening and closing the electromagnetic switch under a low load condition.

According to the third aspect of the invention, the main body side set detection is performed.
Contact for intelligent contact and fixing unit side set detection
After the contact with the connector, the connection of the connector of the fixing temperature detecting member has been securely completed, and there is no connection failure due to incomplete fitting of the connector, and accurate abnormality detection can be performed.

According to the fourth aspect of the invention, the main body side set detection is performed.
Contact for intelligent contact and fixing unit side set detection
After contact with the heater, the heater is
Since controlling the can precise heater control based on a stable pure thermistor information.

According to a fifth aspect of the present invention, the main body side set detection is performed.
Contacts and contacts for fixing unit side set detection
Is brought into a state where the image can be formed after the contact with the fixing unit, so that troubles such as engagement of the fixing unit driving gear can be prevented beforehand.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIGS. 1 to 6 show one embodiment of the present invention.

First, the configuration will be described.

1 to 5, reference numeral 10 denotes a fixing unit detachably mounted on a copying machine main body (not shown in detail). The fixing unit 10 is a known fixing roller.
11, pressure roller 12, infrared heater 13, thermistor 14, fixing claw 15, coating felt 16, pressing cam 17, fixing detection sensor
18, a thermal fuse 19 and the like. The fixing unit 10 presses the transfer paper P passed between the rollers 11 and 12 with the pressing force of the pressure roller 12 while heating the transfer paper P with the heater 13 in the fixing roller 11 to form the transfer paper P on the transfer paper P. After fixing the toner image on the transfer paper P, the transfer paper P on which the image is fixed
Is separated from the fixing roller 11 by the fixing claw 15, and the sheet is discharged. Here, the thermistor 14 is a fixing temperature detecting member that detects a heating temperature of the heater 13, that is, a fixing temperature. The coating felt 16 is impregnated with silicone oil,
Sliding contact with the outer peripheral surface of the fixing roller 11 improves the releasability of the transfer roller P from the fixing roller. The fixing detection sensor 18 is a sensor for detecting the transfer sheet P that has reached a predetermined position, and is for determining whether the transfer sheet P passes through the predetermined position at regular timing. The thermal fuse 19 is blown to prevent excessive heating of the fixing roller 11 and can cut off the power supply to the heater 13.

The fixing device 10 is guided by the left and right guide rails 21 and 22 so as to be movable back and forth, and can be pulled out to the front side of the copying machine main body. The connecting gear 23 is separated from the fixing drive gear 24 on the copying machine main body side, and is connected again when re-installed. A connector support bracket 25 is provided at the rear of the fixing unit 10, and a connector member 51m is fixed to the bracket 25. Further, a connector support bracket 28 is provided at a position where the rear side plate 27 of the copying machine body faces the connector member 51m, and a connector member 51f is fixed to the bracket 28. These connector members 51m and 51f are in a relationship of male and female and constitute a drawer connector 51, and connect an electrical conduction path when the connector member 51m is inserted into the connector member 51f to a specified depth. The drawer connector 51 is a connector capable of connecting and disconnecting the electrical conduction path of the heater 13 and the electrical conduction path of the thermistor 14 housed in the fixing unit 10, respectively.

Meanwhile, as shown in FIGS. 1 and 2, the fixing of the male connector member 51m mounted on the fixing unit 10 side
A fixing unit side heater contact in which a fixing wire 53a is swaged to a part 52a of a unit side connector housing 52.
53 is attached and the fixing unit side connector
The set detection input line 54 is connected to the other part 52b of the
Fixing unit side set detection contact 54 with caulked a
Is attached. A part 56a of the body side connector housing 56 of the female side connector member 51f mounted on the body side is provided with a body side heater caulking a fixing heater supply line 57a.
Data contact 57 is mounted, the main body side connector
The other part 56b of the housing 56 has a set detection input line.
A body-side set detection contact 58 having a caulked 58a is attached. Here, the fixing unit heater heater
The tact 53 is a contact length L behind the reference contact position.
1 is longer than the similar contact length L2 of the fixing unit side set detection contact 54 (L1> L2), and thereby protrudes rearward by a predetermined dimension (L1-L2). On the other hand, the contact for heater on the body side
The front end of 57 is lined up horizontally. Accordingly, when the connector member 51m is inserted into the connector member 51f (when the fixing unit 10 is mounted), the fixing unit heater heater
The heater 53 is inserted to the specified depth and the corresponding heater
After contacting the contact 57 for the fixing, that is, after the connector for the heater is connected,
The tact 54 contacts the corresponding main body side set detection contact 58, thereby detecting the completion of the set.

That is, the fixing unit side set detection
Contact 54 and the corresponding contact for body set detection
The connector 58 constitutes the attachment / detachment detection means 60, and the attachment / detachment detection means 60 is provided in the connector housings 52 and 56 accommodating the heater connector 51. Also, detachment detection means
Reference numeral 60 denotes a connector member 51 when the fixing unit 10 is mounted.
After the m and 51f are inserted to a predetermined depth of the total insertion amount and the connector 51 for the heater 13 is connected, a mounting detection signal is output, and when the fixing unit 10 is detached, the connector 51 for the heater 13 is detached ( The disconnection is detected before it is shut off.

FIG. 6 shows the power supply control means of this embodiment.
It is a diagram of a control circuit 59. In the figure, the SSR 100 is of a type without a built-in zero-cross ignition circuit, and a contact relay (RA) 103, which is an electromagnetic switch, is turned on by a relay ON signal from a CPU 101 with a driver. Lighting control can be performed. C
The PU 101 receives the zero cross signal from the zero cross detection circuit 104, and performs SSR driving or phase control driving based on the zero cross point of the AC voltage supplied from the commercial power supply.
L1 and C2 are LC filters for suppressing the generation of noise due to the triac firing of the SSR 100, and L2 and C1 are line filters to prevent noise from flowing out to other parts.
D is a back electromotive voltage prevention diode. Note that relay 103
Is a normally open type that opens a contact when it is OFF. If an abnormality occurs in the CPU 101, it opens and plays a role as a safety relay.

Next, a control procedure in this embodiment will be described with reference to FIG.

First, in step P11, the setting state of the fixing unit 10 is checked by the attachment / detachment detecting means 60, and if not set, the SSR 100 is turned off in step P12.
After that, in step P13, the heater safety relay 103 is turned off.
FF (heater is turned off), and then, in step P14, a fixing non-setting process is executed. The non-setting process is a process of, for example, displaying a guidance for urging the user to set the fixing unit 10 and setting a copy-prohibited state. Here, the reason why the SSR100 is turned off first is that the SSR100 is turned off.
Is a non-contact, whereas a relay 103 which is an electromagnetic contactor
This is because it is desirable to open and close the relay 103 at light load in order to improve the contact life of the relay 103. Therefore, the heater 13 is turned off first in SSR100.
Then, when no load is applied, the relay 103 is turned off so that the SSR 100 can be reliably operated as a safety relay in the event of an error such as a false call or short-circuit failure. If the fixing unit 10 is set at the time of the set detection check in step P11, the relay 103 is turned on in step P15, and then the normal temperature control of the heater 13 is performed in step P16 based on the temperature detection value of the thermistor 14. Will be

As described above, in the present embodiment, while the heater 13 is controlled to be energized after the attachment / detachment detecting means 60 detects attachment, when the detachment detection means 60 detects detachment, the heater 13 is turned off before the connector of the heater 13 is detached. The operation of the heater 13 is stopped, and the operation of the heater 13 is stopped after the operation of the heater 13 is stopped (turned off).
The contact of the relay 103 connected in series to the terminal is opened. Also,
When the attachment unit is attached, after the connector of the thermistor 14 provided in the fixing unit 10 is connected, the attachment / detachment detection means
60 detects the mounting, and further controls the heater 13 according to the resistance value of the thermistor 14 after the output of the mounting signal of the attachment / detachment detecting means 60, so that the image can be formed after the mounting signal of the attachment / detachment detecting means 60 is output. I have.

In this embodiment, when the fixing unit 10 is released from the set state and is taken out to the front side of the copying machine main body, the connector member 51m is cut off from the connector member 51f, so that the fixing unit side is removed.
Main body side set detection supported by set detection contact 54
Is released from the contact 58 for the fixing unit.
G is separated from the corresponding main body side heater contact 57. At this time, the detachment detecting means 60 detects the detachment before the electric conduction path of the heater 13 is cut off. When the fixing unit 10 is remounted, the drawer connector 51
After the connector members 51m and 51f are fitted to a predetermined depth and the electrical conduction path of the heater 13 and the electrical conduction path of the thermistor 14 are completely connected, the attachment / detachment detecting means 60 outputs a mounting detection signal. Therefore, when the setting of the fixing unit 10 is detected by the signal from the attachment / detachment detection means 60, the electrical conduction path of the heater 13 is already completely connected, and the fitting of the drawer connector 51 is incomplete. This eliminates connection failures that have occurred in the past,
Attachment / detachment of the fixing unit 10 while the heater 13 is ON can be prevented beforehand, and a situation in which contacting is caused by arcing can be avoided.

In this embodiment, the attachment / detachment detecting means is provided.
Since the heater 13 is controlled in accordance with the resistance value of the thermistor 14 after the output of the mounting signal 60, accurate heater control can be performed under a completely connected state of the connector 51, and the copyable state is output after the mounting signal of the attachment / detachment detecting means 60 is output. Therefore, troubles of meshing of the driving gear 24 and the connecting gear 23 for driving the fixing unit 10 and malfunctions due to the troubles can be prevented. Also,
By opening and closing the relay 103 under a low load condition, the service life of the contact can be extended, and when the signal of the attachment / detachment detection means 60 is output, the connection of the connector of the thermistor 14 is completely completed. Will be possible. Also,
The fitting state of the connector 51 can be accurately detected, and the cost of the attachment / detachment detection means 60 can be reduced.

[0028]

Effects of the Invention According to the first aspect of the invention, the detection timing of the attachment detection unit, when mounting the fixing unit slower than the connection of the heater for the conductive paths, from interruption of the heater conduction path during disengagement of the fixing unit Since it is quicker, the attachment / detachment of the fixing unit while the heater is turned on can be prevented beforehand, and the contact can be prevented from melting due to arcing. Further, the connection timing of the heater connector and the connection timing of the attachment / detachment detection signal can be easily mechanically defined, and the cost can be reduced. Also, make sure that the heater connector is completely connected.
The heater can be controlled. Also, when the fixing unit is removed
Kings can be reliably prevented from occurring.

According to the second aspect of the invention, the life of the contacts can be increased by opening and closing the electromagnetic switch under a low load condition.

According to the third aspect of the present invention, the main body side set
Contact for contact detection and the
After the contact with the tact, the connection of the connector of the fixing temperature detecting member is surely completed, so that a connection failure due to an incomplete connector fitting can be eliminated, and accurate fixing temperature detection can be performed.

According to the fourth aspect of the present invention, the main body side set
Contact for contact detection and the
After contact with the tact, the resistance depends on the resistance of the thermistor.
Since so as to control the over data, it is possible to perform accurate heater control based on a stable pure thermistor information.

According to the fifth aspect of the invention, the main body side set
Contact for contact detection and the
Since the image formation is enabled after the contact with the tact, the trouble of meshing of the fixing unit drive gear can be prevented beforehand.

[Brief description of the drawings]

FIG. 1 is a sectional view of a connector according to an embodiment of the present invention.

FIG. 2 is a side view showing an attached state of the connector according to the embodiment of the present invention.

FIG. 3 is a perspective view showing the vicinity of the rear part of the fixing unit according to the embodiment of the present invention.

FIG. 4 is an external perspective view of a fixing unit according to one embodiment of the present invention.

FIG. 5 is a front sectional view of the fixing unit according to one embodiment of the present invention.

FIG. 6 is a control circuit diagram of one embodiment of the present invention.

FIG. 7 is a flowchart showing a control program according to an embodiment of the present invention.

[Explanation of symbols]

10 Fixing unit 11 Fixing roller 12 Pressure roller 13 Heater 14 Thermistor (Fixing temperature detecting member) 51 Drawer connector (Connector) 52 Fixing unit side connector housing 54 Fixing unit side set detection contact (Removal detection means) 56 Main body side connector housing 58 Main body side set detection contact (removal detection means) 59 Control circuit (power supply control means)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 13/20 G03G 15/00 550 G03G 15/20 G03G 21/16-21/18

Claims (5)

(57) [Claims] 1. A image forming apparatus which detachably fixing unit that houses the heater in the image forming apparatus main body, the image forming apparatus main body, for supplying power to the heater
For the main body side heater and the fixing unit
Contact for body set detection to detect the attachment / detachment
And the main body side heater contact and the main body side set.
Connector housing that stores the contact for
Comprising grayed and, wherein the fixing unit includes a contact for the body-side heater
The contact for the fixing unit side heater and the book
The fixing unit side that comes in contact with the body side setting detection contact
A set detection contact and the fixing unit side heater
Contact and the fixing unit
Tact is stored and mated with the connector housing on the body side
A fixing side connector housing, wherein the main body side set detection contact and the fixing unit
Only when the side set detection contact comes in contact with the
Main body side heater contact and the fixing unit side heater
From the image forming apparatus main body through the contact for
Power supply control for controlling power to be supplied to the heater
Means, wherein the main body side connector housing and the fixing side connector housing are provided.
When the housing is fitted, the body heater
Contact and the fixing unit side heater contact
After contact, the main body side set detection contact
The fixing unit side set detection contact comes into contact with the fixing unit side connector housing and the fixing side connector housing.
When the housing is separated from the housing,
Contact and the fixing unit side heater contact
Before detaching, make sure that the main body side set detection contact
An image forming apparatus wherein the fixing unit-side set detection contact is detached . 2. An image forming apparatus according to claim 1, wherein opening the contacts of the series-connected electromagnetic switch in the heater after deactivation of the heater. 3. When the fixing unit is mounted, after the connector of the fixing temperature detecting member provided in the fixing unit is connected, the main body side set detecting contact and the fixing unit are connected.
The image forming apparatus according to claim 1, wherein the knit side set detection contact is in contact with the knit side set detection contact . 4. A main body side set detection contact and a front side.
The image forming apparatus according to claim 1, wherein the heater is controlled in accordance with the resistance value of the thermistor after the contact with the fixing unit side set detection contact . 5. A main body side set detection contact and a front side.
The image forming apparatus according to claim 1, wherein the image forming apparatus is set to an image-capable state after the contact with the fixing unit-side set detection contact .