JPH01293375A - Image forming device - Google Patents

Abstract

PURPOSE:To facilitate and ensure safe detaching work by arranging a fixing device so as to be attachable and detachable from the main body of an image forming device and preventing the fixing device from being detached when temperature inside it is higher than a prescribed value. CONSTITUTION:The fixing device 18 is arranged so that its entire body or a part is attachable and detachable from the main body 30 of the image forming device, while it is equipped with a detaching preventing mechanism to prevent the entire body or a part of the fixing device 18 from being detached. In addition, a detaching preventing mechanism driving means 19 is arranged so as to drive the detaching preventing mechanism and prevent the fixing device from being detached from the main body 30 of the image forming device when the temperature inside fixing device 18 is higher than the prescribed value. As a result, manhour in the manufacturing process of the image forming device can be restrained from increasing. Work to detach the fixing device from the main body of the image forming device is facilitated, thereby ensuring the safe detaching work.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to image forming apparatuses, and particularly to image forming apparatuses such as electrophotographic copying apparatuses and laser beam printers equipped with a fixing device for fixing a visible image formed on a transfer material. The present invention relates to an image forming apparatus.

As is well known, this type of image forming apparatus is provided with a fixing device along with an image forming section, a transfer material conveyance system, etc., and a visible image formed on the transfer material by the fixing device. The image is fixed onto the transfer material. To further explain the above-mentioned fixing device, the fixing device includes charging performed in the image forming section,
When a transfer material on which a visible image corresponding to the original image information has been formed through the image exposure, development, and transfer steps is conveyed by a transfer material conveyance system, this transfer material is transported by a fixing roller and a pressure roller. The image is fixed by being heated and pressed by a pair of rollers. In addition to the above-mentioned fixing roller and pressure roller, the fixing device also includes a fixing heater installed on a rotating shaft that rotatably supports the fixing roller, and a thermistor that detects the temperature of the outer circumferential surface of the fixing roller and pressure roller. , a drive power source that supplies power to the fixing heater, and a drive power source that reads the detection signal output from the thermistor and drives the fixing heater in order to adjust the temperature of the outer circumferential surface to the temperature necessary for image fixing at all times during the image forming sequence. It has a control system etc. to control it.

By the way, in the conventional image forming apparatus having the above-mentioned configuration, the fixing device is built into the main body of the image forming apparatus along with the image forming section, the transfer material conveyance system, etc. It was not configured to be detachable from the main body of the device. Therefore, the lifespan of the fixing device itself must be manufactured to approximately match the lifespan of the image forming process. Quality control and process control must be carried out to match the lifespan, etc., which has the drawback of increasing man-hours and reducing work efficiency. Furthermore, if a situation arises in which only the fixing device breaks down while the image forming apparatus is in use, it is not easy to remove the broken fixing device from the image forming apparatus main body, and the fixing device cannot be easily removed. If the temperature is high, there is a risk that dangerous accidents such as burns to workers may occur.

Therefore, the present invention was devised to eliminate the above-mentioned drawbacks, and its purpose is to suppress the increase in man-hours in the manufacturing process of an image forming apparatus, and to eliminate the need for removing the fixing device from the main body of the image forming apparatus. It is an object of the present invention to provide an image forming apparatus which is easy to work with, and which allows a worker to perform the work safely and reliably without suffering accidents such as burns during the removal work.

1. Summary The above objects are achieved by an image forming apparatus according to the present invention. In summary, one aspect of the present invention is to receive a recording material onto which a visible image formed through a predetermined image forming process is transferred,
In an image forming apparatus having a fixing device for fixing the visible image onto a recording material, all or part of the fixing device is
The fixing device is configured to be detachable from the main body of the image forming apparatus, and is provided with a detachment prevention mechanism that prevents all or part of the fixing device from detaching from the main body of the image forming device, and the internal temperature of the fixing device is maintained at a predetermined level. The image forming apparatus is characterized in that the image forming apparatus is provided with a detachment prevention mechanism driving means that drives the detachment prevention mechanism to prevent the fixing device from detaching from the image forming apparatus main body when the fixing device is greater than a value.

1 pot An embodiment of the present invention will be described below with reference to one drawing.

FIG. 2 shows an image forming apparatus according to an embodiment of the present invention. The outline of the image forming apparatus according to an embodiment of the present invention is as described below. That is, in FIG. 2, a paper feed tray 1 is provided below the right end of an image forming apparatus main body (hereinafter simply referred to as "apparatus main body") 30 in FIG. A paper discharge tray 12 is provided directly above the paper feed tray 1 and is detachably attached to the apparatus main body 30.

A front door 13 is provided on the minus side of the portion of the apparatus main body 30 where the paper discharge tray 12 is attached, and is openable and closable. A front door opening sensor (not shown) is provided at the front 713 to output a predetermined detection signal when the front door 13 is in an open state. Device body 30
An image forming section 32 and a paper feeding mechanism 34 adjacent to the image forming section 32 are disposed in an area extending from the right end in FIG. .

In this embodiment, a fixing device 18 is disposed in an area above the paper feed mechanism 34 in the apparatus main body 30 in correspondence with the paper ejection tray 12.
All members including the frame 18a constituting the device 8 are configured to be detachable from the device main body 30 together with the frame 18a.

Note that in the fixing device 18, for example, only the fixing roller 14a and the pressure roller 14b may be configured to be detachable from the device main body 30.

The above configuration will be described in more detail as follows. That is, the image forming section 32 includes an optical unit 8 provided in the lower left area of the apparatus main body 30, and a photosensitive drum 6 provided close to the paper feeding mechanism 34 and the fixing device 18.

A charging roller 7 and a developing device 9 are provided along the outer peripheral surface of the photoreceptor drum 6 with the photoreceptor drum 6 at its center. It has a transfer roller IO and a cleaning device 36. The photosensitive drum 6 is rotatably supported in the direction of the arrow in FIG. 2 (ie, counterclockwise). The charging roller 7 is, for example,
It is rotatably supported in a clockwise direction in FIG. 2, and comes into contact with the outer peripheral surface of the photoreceptor drum 6 to charge the outer peripheral surface of the photoreceptor drum 6 substantially uniformly. optical unit 8
The image forming apparatus scans the outer peripheral surface of the photoreceptor drum 6 by scanning a laser beam modulated in accordance with the original image information through a rotating polygon mirror from a gap defined by the charging roller 7 and the developing device 9. static 'i1! on the outer peripheral surface of 6! It forms a latent image.

The developing device 9 is disposed downstream of the charging roller 7 in the rotational direction of the photosensitive drum 6 via the above-mentioned gap.

The developing device 9 has a developing roller 9a, and when a developing bias is supplied to the developing roller 9a from a developing bias power source (not shown), one layer of developer stored in the developing device 9 is generated. The electrostatic latent image formed on the photosensitive drum 6 is turned into a visible image. The transfer roller IO is disposed downstream of the developing device 9 in the rotational direction of the photoreceptor drum 6 so as to be freely rotatable, for example, clockwise in FIG. It is configured to transfer an image onto a recording material, that is, a transfer material P provided via a paper feeding mechanism 34, which will be described later. The cleaning device 36 is disposed upstream of the charging roller 7 in the rotational direction of the photoreceptor drum 6, and scrapes and collects residual toner on the outer peripheral surface of the photoreceptor drum 6. The paper feed mechanism 34 includes a paper feed roller 2 rotatably disposed clockwise in FIG. 2, a paper feed pad 3 and a paper feed sensor 5 provided along the outer peripheral surface of the paper feed roller 2. It has A roller pad 4 is partially attached to the outer peripheral surface of the paper feed roller 2. The paper feed roller 2 rotates to feed the transfer material P placed on the paper feed tray 1.
The sheets are fed one by one to a portion of the image forming section 32 where the photosensitive drum 6 and the transfer roller 10 are provided at a predetermined timing. The roller pad 4 is the paper feed roller 2
The paper feed pad 3 comes into contact with the transfer material P as it rotates.
At the same time, the transfer material P can be smoothly fed to the above-mentioned portion by the paper feed roller 2. The paper feed sensor 5 is configured to detect the transfer material P fed into the portion of the image forming section 32 by the paper feed roller 2, and output a predetermined detection signal.

To explain the above-mentioned fixing device 2218 in detail, the fixing device!
Reference numeral 118 includes a frame 18a that is attached to the apparatus main body 30 and has openings facing the image forming section 32 side and the paper discharge tray 12 side, as well as a fixing roller 14a provided inside the frame body 18a. , a pressure roller 14b provided in contact with the outer peripheral surface of the fixing roller 14a, and the fixing roller 14.
a thermoswitch provided in contact with the outer peripheral surface of a;
Paper ejection roller 1 provided at the opening on the paper ejection tray 12 side
1 and a solenoid 19 provided at a portion of the frame body 18a corresponding to a diagonally below the pressure roller 14b. The fixing roller 14a is rotatably supported for one rotation.
A fixing heater 15 is provided on the shaft supporting the fixing roller 14a. The pressure roller 14b is rotatably supported in a direction opposite to the rotational direction of the fixing roller 14a.

The fixing roller 14a and the pressure roller 14b receive the transfer material P sent out from the image forming section 32 and onto which the visible image has been transferred, and fix the visible image by heating and pressurizing the transfer material P. . The paper discharge roller 11 receives the transfer material P on which the image has been fixed by the fixing roller 14a and the pressure roller 14b, and discharges it to the paper discharge tray 12. Thermoswitch 6 and solenoid 19
This will be explained in detail later.

In the image forming apparatus configured as described above, when a driving power source (not shown) for the image forming apparatus is turned on, the apparatus starts driving. When an operator operates an operation button (not shown) and an image forming sequence execution command signal is input from the operation button, the fixing roller 14
a. A check is made to see if the temperature of the outer peripheral surface of the pressure roller 14b has reached a predetermined value. When the above check is completed, the image forming sequence is executed. The charging roller 7 charges the outer peripheral surface of the photosensitive drum 6 substantially uniformly, and the paper feed roller 2 is driven to start feeding the transfer material P on the paper feed tray 1 to the image forming section 32 . When the leading edge of the transfer material P fed from the paper feed tray 1 by the drive of the paper feed roller 2 reaches the paper feed sensor 5 and a predetermined detection signal is output from the paper feed sensor 5, the detection signal is In synchronization with the output timing, the optical unit 8 forms an electrostatic latent image on the photoreceptor drum 6 corresponding to the document image information. This electrostatic latent image is converted into a visible image by a developing device 9, and is transferred by a transfer roller 10 to a transfer material P that is sent to an image forming section 32 at a predetermined timing. Transfer material P onto which the visible image has been transferred in this way
is sent to the fixing device 18, and the fixing rollers 14a,
After the image is fixed by the pressure roller 14b, the paper is discharged onto the paper discharge tray 12 by the paper discharge roller 11.

FIG. 1 shows a control system of a fixing device included in an image forming apparatus according to an embodiment of the present invention. As is clear with reference to FIG. 1, the detachment prevention mechanism includes a coupling plate 20 that can be freely fitted into and detached from a keyhole formed in the frame 18a, and is biased in a direction to cause the coupling plate 20 to detach from the keyhole. A solenoid 19 which is connected to a spring 24 and a detachment protection mechanism driving means, that is, a connecting plate 20. Solenoid 19
A control unit 22 and a fixing roller 14 that control the
It consists of a thermistor 17 disposed near the outer peripheral surface of a, a drive power source 21, a front door switch 23, and a thermoswitch 16. The thermo switch 16 is opened when the temperature of the outer peripheral surfaces of the fixing roller 14a and the pressure roller 14b reaches a predetermined value or more, and cuts off the power supply to the fixing heater 15 from the drive power source 21. It is a normally closed contact that returns to its original position when the temperature of the outer peripheral surface falls below a predetermined position.

The front door switch 23 is mechanically connected to the front door 13, opens when the front door 13 opens, cuts off power supply to the fixing heater 15 from the drive power source 21, and closes the +m door 1.
When the door 3 is closed, the fixing heater 15 is closed and power supply from the drive power source 21 to the fixing heater 15 is continued. The thermistor 17 is connected to the fixing roller 14a and the pressure roller 14b.
The outer peripheral surface temperature of the sensor is detected and an electrical signal corresponding to the detected outer peripheral surface temperature is output. The drive power supply 21 is
Supply power to the fixing heater 15 from the drive power source 21 based on a drive command signal output from the control unit 22
The amount is controlled. Solenoid 19 is
It is excited by the drive command signal outputted from the control unit 22, and while it is in the excited state, the joint plate 20 is moved against the biasing force of the spring 24 to move the joint plate 20 to the frame 18.
It is designed to be held in a state where it is fitted into the keyhole a. The control unit 22 includes an arithmetic control section, a storage section,
It has an input/output interface. The storage section includes a control program and the like, and also stores necessary data. The data stored in the recording section is, for example, when the solenoid 19 is energized and the fixing device is activated! ! ? There is data on the outer circumferential surface temperature values (40° C. or higher) of the fixing roller 14a and the pressure roller 14b when it is necessary to prevent them from being removed from the apparatus main body 30 of No. 18. The arithmetic control section performs arithmetic operations and logical operations.The arithmetic control section checks whether or not a predetermined detection signal is output from a front door opening sensor (not shown), and determines whether or not the predetermined detection signal is output. When it recognizes that the temperature value of the outer peripheral surface of the fixing roller 14a and the pressure roller 14b outputted from the thermistor 17 is read, it is compared with the data stored in the storage section and calculated. . When the calculation control unit recognizes that the detected temperature value is equal to or larger than the data as a result of the comparison calculation, it makes it impossible to remove the fixing device 2118 from the apparatus main body 30. A drive command signal is output to the solenoid 19 to fit the joint plate 20 into the keyhole. When the calculation control unit recognizes that the detected temperature value is smaller than the data as a result of the comparison calculation, the calculation control unit demagnetizes the solenoid 19 to enable removal of the fixing device 18 from the device main body 30; Joint plate 2
0 is released from the keyhole. When the arithmetic and control unit demagnetizes the solenoid 19 and releases the joint plate 20 from fitting into the keyhole, the arithmetic and control unit displays whether the fixing device 18 is displayed on a display unit (not shown). A display command signal is output to indicate that removal from the A-mounted body 30 is now possible. The calculation control unit controls the front door 1 based on the output signal from the front door opening sensor (not shown).
3 recognizes that the door has shifted from the open state to the closed state, outputs a drive command signal to the solenoid 19 to make it impossible to remove the fixing device 18 from the device main body 30, and fits the joint plate 20 into the keyhole. It is designed to let you do so. When the arithmetic control unit recognizes that the front door 13 is in the closed state based on the output signal from the front door opening sensor (not shown), the arithmetic control unit controls the fixing roller 14a output from the thermistor 17.
When the image forming sequence is executed by reading the outer peripheral surface temperature detection signal of the pressure roller 14b, the temperature value of the outer peripheral surface of the fixing roller 14a and the pressure roller 14b is set to an appropriate temperature for image fixing. Furthermore, when the image forming sequence is not being executed, a drive command signal (on/off signal) is output to the drive power source 21 to control the fixing heater 1 so that the outer circumferential surface temperature value becomes a predetermined standby temperature.
5.

Next, the control operation of the control system configured as described above will be explained mainly with reference to the flowchart shown in FIG.

When the arithmetic control unit recognizes that the front door 13 is open due to the output of a predetermined detection signal from the front door opening sensor (not shown) (stay 2 step 101), the arithmetic control unit detects the output from the thermistor 17. The outer circumferential surface temperature detection signals of the fixing roller 14a and the pressure roller 14b are read, and the temperature detection signals and the outer circumferential surface temperature value data (40° C.) stored in the storage section are compared and calculated (step 103). ,
If it is recognized in step 103 that the temperature detection signal is equal to or larger than the data, the solenoid 19
is excited to fit the connecting plate 20 into the keyhole (step 11).
1) When it is recognized in step 103 that the temperature detection signal is smaller than the data, the solenoid 19 is held in a demagnetized state to release the joint plate 20 from the keyhole, and step 105), the display section (not shown) outputs a display command signal to display that the fixing device 1t18 can be removed from the apparatus main body 30 (step 107). When it is recognized in step 101 that the front door is closed, Proceeding to step 109, the solenoid 19 is energized as in step lil to fit the connecting plate 20 into the keyhole.

According to one embodiment according to the invention described above, the fuser, i!
118 is configured to be detachable from the main body 30 of the apparatus, and the housing of the fixing apparatus 18 cannot be removed from the main body 30 when the temperature inside the fixing apparatus 18 is higher than a certain temperature value (40° C.). Therefore, when replacing the fixing device 18 with a new one, accidents such as burns caused by the hot fixing device 18 can be prevented from occurring.

FIG. 4 shows an image forming apparatus according to another embodiment of the present invention. In this embodiment, the detachment prevention mechanism is comprised of a keyhole formed in the main body 30 of the apparatus and a connecting plate 27 that can be freely fitted and removed. A spring (not shown) biases the coupling plate 27 in a direction to separate it from the keyhole, and the separation prevention mechanism driving means has one end connected to the frame 18 of the fixing device 18.
It is attached to the protruding part provided in a, and the other end side is the connecting plate 27.
It was decided to consist of a bimetal plate 26 that is connected to. - In the configuration described above, the bimetal plate 26 begins to bend as the temperature of the outer peripheral surfaces of the fixing roller 14a and the pressure roller 14b increases, and when the outer peripheral surface temperature reaches 50°C, the fourth
As shown by the solid line in the figure, the joint plate 27 fits into the keyhole of the apparatus main body 30, and thereby the fixing device 2!18 is attached to the apparatus main body 30.
You will not be able to leave from 0. When the outer circumferential surface temperature begins to fall, the bimetal plate 26 begins to gradually extend upward in FIG. At this point, the bimetal plate 26 and the connecting plate 27 move to the position shown by the broken line in FIG.

Therefore, the fixing device 18 can be removed from the device main body 30.

According to another embodiment according to the invention described above, the ta plate 27
Since the keyhole is fitted into the keyhole only by the bimetal plate 26, it is possible to provide an image forming apparatus that is much cheaper than the apparatus according to the first embodiment.

As described above, according to the present invention, it is possible to suppress the increase in the number of T in the manufacturing process of the image forming apparatus, and it is possible to easily remove the fixing device from the image forming apparatus and the main body. It is possible to provide an image forming apparatus in which the operator can perform the removal work safely and reliably without suffering accidents such as burns.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a control system of a fixing device included in an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing the overall configuration of an image forming apparatus according to the present invention. FIG. 3 is a flowchart showing the control operation of the control system shown in FIG. 1. FIG. 4 is a partial explanatory diagram of an image forming apparatus according to another embodiment of the present invention. 17: Thermistor 18: Fixing device 18a: Frame Body 19: Solenoid 20. 27: Joint plate 22: Control unit 24 Spring 26: Bimetal plate 30: Device body P: Transfer material 7Z Shear 4Z 3Q

Claims (1)

[Claims] 1) In an image forming apparatus having a fixing device that receives a recording material onto which a visible image formed through a predetermined image forming process has been transferred and fixes the visible image onto the recording material, all or part of the fixing device The unit is configured to be detachable from the image forming apparatus main body, and is provided with a detachment prevention mechanism that prevents all or part of the fixing device from detaching from the image forming apparatus main body, and the internal temperature of the fixing device is 1. An image forming apparatus comprising: a detachment prevention mechanism driving means for driving said detachment prevention mechanism to prevent the fixing device from detaching from the image forming apparatus main body when the fixing device is greater than a predetermined value.