JPH07107626B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

[Prior Art] Conventionally, as for an electronic copying machine using a heat fixing device using a halogen heater as a heat source, as shown in FIG.
The temperature inside the machine due to the above or the temperature rise from the light source for exposure, for example, the halogen lamp 3 is exhausted to the outside of the machine by the single fan 2. However, conventionally, the heat fixing device 1 was constantly controlled to a predetermined temperature, for example, 160 ° C. even when not copying, that is, during standby, so that it was necessary to rotate the fan 2 even during standby to perform heat exhaustion. . For this reason, the fan driving motor 2'is constantly rotating while the main switch 4 is connected, and there are complaints from the user that the wind noise is particularly noisy during standby, and the fan motor 2'is also costly. It is in a situation where it is treated as an expensive part in the configuration.

[Object] It is an object of the present invention to provide an image forming apparatus that achieves noise reduction and cost reduction when image formation is not performed, and prevents internal temperature rise when image formation is not performed. A fixing means for heating and fixing the unfixed toner image on the recording material, and an energization control means for starting energization of the fixing means at the same time as turning on the power to the apparatus main body to maintain the fixing means at a predetermined set temperature. A main motor that rotates only while an image formation start signal is input and an image is formed on a recording material, and an exhaust fan that exhausts the fixing portion by the driving force of the main motor are provided. Provided is an image forming apparatus, characterized in that when the image forming start signal is not input for a predetermined time after being turned on and when the image forming start signal is not input for a predetermined time after the image formation is finished, the energization to the fixing unit is cut off. To do.

Embodiments Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective perspective view showing an embodiment of the present invention.

FIG. 1 shows an electronic copying machine, and a light source and means for performing each step except fixing and cooling in the electrophotographic step are not shown.

Reference numeral 1 is a heat fixing device in which a heat roller 1a having a heat source inside and a pressure roller 1b are in contact with each other and rotate, and a transfer material passes between them. The thermal fixing device 1 may be of any other type as long as it heats the developer on the transfer material with a heat source and fixes the developer on the transfer material.

A temperature sensor 10 for detecting the surface temperature of the heat roller 1a is provided so as to approach or approach the surface of the heat roller 1a.
The signal for controlling the energization of the heat source of the heat roller 1a during standby for the copy operation is timed so that the temperature inside the device is kept within the allowable temperature range due to the connection of a substantially constant temperature after the heat roller 1a is heated. A control device 11 is provided which includes the controlling operations.

The cooling device for cooling the inside of the device is as follows.

The self-cooling fan 6 is fixed to the output end of the main motor 5, and the self-cooling fan 6 and the pulley 6a are integrally formed. A belt 9 is wound around the pulley 6a and a pulley 6b fixed to the end of a fan shaft 2a, which is rotatably supported by a bearing (not shown) and includes a fan 2. Therefore, the fan 2 rotates the pulley 6a only while the main motor 5 is rotating, that is, during the copying operation, and the pulley 6b is driven to rotate via the belt 9 to rotate the fan shaft.
2a will be rotated and will rotate. Then, the fan 2 discharges the air inside the machine. The fan 2 also serves to absorb ozone generated during copying. Reference numeral 7 is a copy switch for starting copying, and 8 is a weight lamp.

Reference numeral 4 denotes a main switch, which is energized to the heat fixing device 1 by turning on the main switch 4, and the temperature sensor 10 and the control device are connected.
According to 11, the temperature is adjusted at the fixing temperature or lower. In the control device 11, there is further provided a means for continuously turning off the temperature until the device rises to a constant allowable temperature, that is, an allowable maximum temperature, and then turning off the power, that is, for example, a time-interruption relay. . Alternatively, a temperature detecting means (not shown) is provided near the developing device which is most affected by the temperature rise in the device.
Thus, the power supply from the power source to the thermal fixing device 1 is cut off.

As shown in FIG. 3, after the power is turned on at time T0, the temperature of the heat fixing device 1 is adjusted for a predetermined period of time t1 and thereafter the power supply to the thermal fixing device 1 is cut off.
As a result, the temperature inside the device is kept within the temperature rise limit. When the copy switch 7 is pressed at time T1, the heat source of the heat fixing device 1 is energized, and then the normal copy sequence is executed at time T2 when the surface temperature of the heat roller 1a reaches a predetermined temperature. The surface temperature of the heat roller 1a is adjusted to the fixing temperature of 160 ° C. during the copying operation. At the same time T1, the rotation starts and the main motor 5 continues to rotate, which has the effect of clearly informing the user that the copying operation has been accepted. The weight lamp 8 also starts blinking at the same time when the copy switch 7 is turned on, and changes to a lighting state when the heat roller 1a reaches a predetermined temperature. After that, when the copying is completed at time T3, the lighting lamp 8 again shifts to a non-lighting state. After completion of copying, the temperature is adjusted at a predetermined temperature for a predetermined time t2, and thereafter, the power supply to the heat source of the heat roll 1a is cut off.

In the present invention, it is not necessary to match the temperature control temperature during copying with the temperature control temperature during standby. The temperature control during the predetermined time during standby is set within the maximum allowable range of the temperature rise in the machine in consideration of the time required for the user to prepare and replace the document. Therefore, the document preparation and replacement time normally ends within the time t1, but this does not always happen, so the heat source of the heat roller 1a is cut off.

[Effect] As described above, according to the present invention, there is a sound deadening effect when the image formation is not performed, and further, a motor only for driving the exhaust fan is not necessary. Furthermore, even in a low-cost device in which the exhaust fan is driven by the main motor with low noise, it is possible to prevent damage to internal equipment due to temperature rise inside the machine.

[Brief description of drawings]

1 is a perspective view of an embodiment of the present invention, FIG. 2 is a view showing a main motor in which a pulley is integrally formed with a main motor self-cooling fan of the present invention, and FIG. 3 is a timing chart of the present invention,
FIG. 4 is a perspective view of a conventional example. 1 ... Thermal fuser, 2 ... Juan, 5 ... Main motor,
10 ... Temperature sensor, 11 ... Control device.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsukinori Kuroda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-55-113058 (JP, A) -92954 (JP, U)

Claims (1)

[Claims] 1. A fixing means for heating and fixing an unfixed toner image on a recording material, and an energization control means for starting energization of the fixing means at the same time when the main body of the apparatus is turned on to maintain the fixing means at a predetermined set temperature. And a main motor that rotates only while an image formation start signal is input and image formation is performed on the recording material, and an exhaust fan that exhausts the fixing portion by the driving force of the main motor. The image forming apparatus is characterized in that when the image forming start signal is not inputted for a predetermined time after the power is turned on to the main body of the apparatus and the image forming start signal is not inputted for a predetermined time after the image formation is finished, the energization to the fixing means is cut off. .