JPS63144380A - Fixing device - Google Patents

Abstract

PURPOSE:To give an exact fixing property in accordance with the kind of paper, and also, to prevent a trouble in an operation, by switching a set temperature control state to a second temperature control mode from a first temperature control mode, and resetting the state to the first temperature control mode after a prescribed time has elapsed. CONSTITUTION:A control means 16 for controlling a heater 13 consists of, for instance, a microcomputer, and controls the heater 13 so that the temperature controlled state of a fixing roller 9 becomes the first temperature control mode being suitable for the fixation of cardboard. When a switching signal for informing that the kind of paper is changed to thin paper is inputted from a push-button switch 18, the heater 13 is controlled so as to switch the fixing roller 9 to the second temperature control mode. In this case, a timer 17 starts counting, and when an image forming start signal is not inputted, the second temperature control mode is released and reset to the first temperature control mode, at the time point when counting is executed for a prescribed time.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a fixing device applied to electrophotographic copying machines, laser beam printers, etc. The present invention relates to a fixing device that fixes a toner image to a material.

(Prior Art) For example, a fixing device configured as shown in FIG. 6 is known as a fixing device installed in an electrophotographic copying machine, a laser beam printer, or the like. In the same figure, 10
7 is a fixing means, which includes fixing rollers 1 that rotate while being pressed against each other;
09 and a pressure roller 110, and an entrance guide 11 is provided on the entrance side (right side in the drawing) of this fixing means 107.
1 is arranged, and a separation claw 11 is arranged on the exit side (left side in the drawing).
2 is placed.

A heater 113 is provided inside the fixing roller 109.
Further, a temperature sensing element 114 made of a thermistor or the like is provided on the peripheral surface, and energization to the heater 113 is controlled by the output level of the temperature sensing element 114. Note that 115 is a cleaner.

According to the fixing device, the transfer material 106 to which the toner image 110 has been transferred is guided by the entrance guide 115 and introduced between the fixing roller 109 and the pressure roller 110. The toner image 110 is transferred to the exit side by the rotation of the llO, and is heated and pressurized during this transfer to fix the toner image 110. After that, the toner image 110 is shunted from the fixing roller 109 by a separation claw 112, and placed on a tray by a discharge roller (not shown). be discharged.

By the way, there are a wide variety of transfer materials used in copiers, laser beam printers, etc., ranging from thin paper such as second original drawing paper to thick paper such as Bakaki. Therefore, the above-mentioned fixing device also uses a wide variety of transfer materials. It is necessary to provide each with reliable fixing properties.

(Problem to be Solved by the Invention) However, the temperature control set for the fixing roller 109 is usually one, and therefore it is difficult to provide reliable fixing performance to a wide variety of transfer materials. 0 For example, if the temperature control temperature of the fixing roller 109 is set to a relatively high temperature of about 190° C., the fixing properties for thick paper such as postcards will be good, but for 11 paper it will be overripe. hand,
Hot off cents may occur and the image may become dirty, or the Cleaner 1
Problems such as increased toner accumulation in the toner 15 shorten the life of the cleaner and increase paper curl occur. On the other hand, when the temperature control temperature of the fixing roller 109 is set to a relatively low temperature of about 170° C., the fixing performance for thin paper is good, but the amount of heat is insufficient for thick paper, resulting in poor fixing and low temperature. Problems such as offset arise.

In order to solve this problem, a fixing device was proposed that changed the temperature control according to the paper type, but it was necessary to change the temperature control every time the paper type was changed, which was troublesome for the operator. There was a problem with this.

Therefore, the present invention has been made in order to solve the above-mentioned problems of the prior art.The purpose of the present invention is to provide reliable fixing properties depending on the paper type, and to provide a fixing method that does not require much effort to operate. The purpose is to provide equipment.

(Means for Solving the Problems) In the present invention that achieves the above object, in a fixing device that fixes a toner image on a transfer material by a fixing unit heated by a heat source, a temperature set in the fixing unit is set. The heating source is equipped with a control means for controlling the heating source so as to switch the temperature control mode from the first temperature control mode to the second temperature control mode in response to a switching signal, and to return to the first temperature control mode after a predetermined period of time has elapsed. It is characterized by

(Function) In the present invention having the above configuration, when a switching signal is input to the control means, the heating source is controlled to change the temperature control state of the fixing means from the first temperature control mode to the second temperature control mode. Switch. After the predetermined time has elapsed, the fixing means returns to the first position without any operation.
Return to temperature control mode.

(Example) The present invention will be explained below based on illustrated embodiments.

Fig. 1 shows a laser beam printer equipped with a fixing device according to the invention.6 In the same figure, l is a photosensitive drum, which rotates in the direction of arrow a, and is uniformly charged by a charger 2. After that, it is scanned and exposed with laser light from a laser scanner 3 to form an electrostatic latent image. This electrostatic latent image is developed with a developer (toner) by a developing device 4 to become a visible toner image), and is transferred onto a transfer material 6 by a transfer charger 5. The transfer material 6 onto which the toner image has been transferred is fixed by a fixing means 7 and then discharged onto a tray 8.

FIG. 2 shows an example of a fixing device according to the present invention.

The fixing means 7 is composed of a fixing roller 9 and a pressure roller lO, which rotate while being pressed against each other. On the inlet side (right side in the drawing) of the fixing means 7, the transfer material 6 on which the toner image 10 has been transferred is transferred to the fixing roller 9. A population guide 11 is arranged between the fixing roller 9 and the pressure roller 10, and a separating claw 12 is arranged on the exit side (left side in the drawing) for separating the transfer material 6 after fixing by the fixing roller 9. There is.

A heater 13 serving as a heating source is provided inside the fixing roller 9.
A temperature sensing element 14 such as a thermistor for detecting the surface temperature and a cleaner 15 for removing toner and paper powder adhering to the peripheral surface are arranged on the peripheral surface. Note that the fixing roller 9 has a metal cylinder 9a made of aluminum or the like with PTFE on the circumferential surface.
Outer coating 9b made of FE (polytetrafluoroethylene), etc.
It is configured with the following. Further, the pressure roller 10 is constructed by providing a heat-resistant elastic body 10b and a silicone rubber layer 10c on a core bar 10a made of iron or the like.

Next, the features of the present invention will be explained. The control means 16 for controlling the heater 13 is composed of, for example, a microcomputer, and is programmed with control contents as shown in FIG.

According to this control, when the power of the laser beam printer is turned on, the heater 13 is controlled so that the temperature control state of the fixing means (fixing roller 9) is in the first temperature control mode. In this first temperature control mode, as shown by the solid line A in FIG. The temperature control of the roller 9 is set at 180° C., which is suitable for fixing cardboard. Note that when image formation is not performed, the temperature control temperature of the fixing roller 9 is set at standby (17
0°C).

While the first temperature control mode is being executed, it is constantly determined whether a switching signal indicating that the paper type has been changed to thin paper has been input from the push button switch 18. When this switching signal is input, the heater 13 is controlled to switch the fixing roller 9 to the second temperature control mode. In this second temperature control mode, as shown by the dotted line B in FIG. Adjust temperature to 1
Set to 70°C. When switched to the second temperature control mode, the timer 17 provided in the control means 16 starts counting time, and the second temperature control mode is maintained while counting up to a predetermined time, for example, 60 seconds. If the image formation start signal is not input during this count, the temperature control sensitivity of the fixing roller 9 is left at standby (160°C), and when the timer 17 counts 60 seconds, the second
The temperature control mode is canceled and the temperature control mode returns to the first temperature control mode.

When the image formation start signal is input, the temperature control temperature of the fixing roller 9 is set to 170° C., and after the image formation is completed, the timer 17 is reset, and the fixing roller is maintained in the second temperature control mode for 10 seconds, for example. 9) is maintained at 160℃, which is the temperature control temperature during standby), and timer 17 is set to 10.
When the seconds are counted, the mode returns to the first temperature control mode.

Here, the reason why the second temperature control mode was maintained for a certain period of time (10 seconds) without immediately returning to the first temperature control mode after image formation was completed was that the second temperature control mode was maintained for a certain period of time (10 seconds) after the same paper type was used. This is because the frequency of image formation is high, and thereby the time required for switching control can be saved and responsiveness can be improved.

Note that the detection signal of the temperature sensing element 14 is generated during the operation of the heater 13.
The temperature is input to the control means 16, and based on this, the control means 16 controls the heater 13 so as not to deviate from the temperature control set in each temperature control mode.

The switching signal may be sent from the push button switch 18 as described above, but if the laser beam printer is connected to the host computer, it may be sent from the host computer side.

In addition, the second temperature control mode described above is the same as the one-dot chain line C in FIG.
As shown in FIG. 3, the temperature 3I of the fixing roller 9 may be set to 170° C. both during standby and during image formation (fixing).

FIG. 5 shows another example of the first temperature control mode and the second temperature control mode. In this first temperature control mode, as shown by the solid line A in FIG. 5, the fixing roller 9
Set the temperature control temperature to 160℃, and when forming an image (during fixing)
The temperature control temperature of the fixing roller 9 is set to 170°C. In addition, in the second temperature control mode, as shown by the dotted line B in the figure,
The temperature control temperature of the fixing roller 9 is set to 170 during standby.
°C, and the temperature control temperature of the fixing roller 9 is set to 180 °C during image formation.

In this way, if you set the first temperature control mode to a low temperature,
In addition to being convenient when thin paper is used frequently, there is no risk of high temperature offset etc. occurring when fusing thin paper.
Furthermore, after the second temperature control mode in which the fixing roller 9 is set to a higher temperature is finished, the first temperature control mode is set to a lower temperature, so that in the case shown in FIG. In comparison, there are advantages such as less thermal deterioration of the fixing means 8 (for example, thermal deformation of the heat-resistant elastic body 10b of the pressure roller 10, the silicone rubber surface layer 10c, etc.). In the past, this problem of thermal deterioration often occurred because users left the setting changeover switch on the high temperature side, but this problem can be solved.

(Effects of the Invention) The present invention has the above configuration and operation, and since the temperature control state set in the fixing means is set to two, the first temperature control mode and the second temperature control mode, the transfer It can provide reliable fixing properties depending on the paper type, and even if you switch from the first temperature control mode to the second temperature control mode, the first temperature control mode will automatically switch back after a predetermined period of time. Since it is configured to return to , the effect is that the operation does not require much effort.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a laser beam printer to which a fixing device according to the present invention is applied, FIG. 2 is a schematic diagram showing an embodiment of the fixing device according to the present invention, and FIG. 3 is a diagram showing control contents of a control means. flowchart. 4 and 5 are explanatory views for explaining the contents of the temperature control mode 1.2, and FIG. 6 is a schematic diagram of a conventional fixing device. Explanation of symbols 6...Transfer material 7...Fixing means 9...
Fixing roller 10...Toner image 13...I for heating (heater) 16...Control means 18...Push button switch patent applicant Canon Co., Ltd. - Agent Patent attorney Shin Kazu Sera 1\・' 1゛--- Agent Patent Attorney Back 1) Rule ', Figure 1 Figure 2 Figure 3 Figure 4 Figure 6

Claims (2)

[Claims] (1) In a fixing device that fixes a toner image on a transfer material by a fixing means heated by a heat source, the temperature control state set in the fixing means is switched from a first temperature control mode to a second temperature control mode by a switching signal. A fixing device comprising: a control means for controlling the heat source so as to switch the heat source to the first temperature control mode and return to the first temperature control mode after a predetermined period of time has elapsed. (2) When image formation is performed in the second temperature control mode, the predetermined time is a time that includes maintaining the second temperature control mode for a certain period of time after the image formation is completed. A fixing device according to claim 1.