JPH06214437A - Image forming device - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose is to power on / off the image forming apparatus in synchronization with power on / off of the host apparatus. A first power cord 10 connected to an outlet 68 supplies electric power to a fixing device of a page printer 70. The second power cord 22 connected to the outlet 66 of the host device 62 supplies electric power to the control unit and drive unit other than the fixing device of the page printer 70. Host device 62
When the power switch 64 is turned on, power is supplied to the control unit and the drive unit other than the fixing device of the page printer 70 via the second power cord 22. When power is supplied to the control unit, power supply from the first power cord 10 to the fixing device starts.

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 for forming a toner image on a recording medium and heating and fixing the toner image by a heat fixing means.

[0002]

2. Description of the Related Art Conventionally, the power of an image forming apparatus is supplied from a power supply path independent of other apparatuses, and it is necessary to turn on / off the power of each apparatus separately.

[0003]

However, if the image forming apparatus is connected to a host device such as a computer or a word processor, and the electric power of the image forming device is supplied from the outlet of the connected host device, the power supply is turned on by one switch. Although it can be turned on and off, the image forming apparatus generally consumes a large amount of power, which may exceed the maximum power rating of the host device.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to turn on / off the power of the image forming apparatus in synchronization with turning on / off the power of the host apparatus.

[0005]

In order to achieve this object, the present invention provides a first power supply means connected to an external power source for supplying electric power to the heat fixing means, and a device control other than the heat fixing means. Second part for supplying electric power to the control section and the device driving section
And a control means for stopping the power supply from the first power supply means to the heat fixing means when the power supply by the second power supply means is stopped.

[0006]

The first power supply means is connected to an external power source and supplies power to the heating and fixing means. The second power supply unit is connected to an external power source and supplies power to the device control unit and the device drive unit other than the heat fixing unit. When the power supply by the second power supply means is stopped, the power supply from the first power supply means to the heat fixing means is stopped by the control means.

[0007]

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

FIG. 2 is a schematic cross-sectional view of a page printer 70 embodying the present invention. The apparatus is covered with a frame 39, and a paper feed cassette 44 is attached to the opening thereof.
The paper feed cassette 44 is filled with printing paper as a recording material. Inside the frame 39, an exposure unit 40, an image forming unit 42, a fixing unit 54, a mechanism for conveying a print sheet,
A mechanism for driving and controlling them is contained. The image forming unit 42 includes a photosensitive drum 46 and a charger 48.
The developing cylinder 50 and the transfer roller 52. The fixing device 54 includes a fixing roller 56 and a pressure roller 58.
The fixing heater 20 is installed inside the fixing roller 56. The printing paper is conveyed along the conveyance path 60.

FIG. 1 is an electrical schematic diagram of the page printer 70. The first power cord 10 connected to the commercial power source supplies electric power to the fixing heater 20 via the switch 14, the relay 16 and the thyristor 18 via the first inlet 12. Second power cord 2 connected to commercial power
2 supplies power to the power supply circuit 28 via the second inlet 24, the switch 14, and the filter 26. The power supply circuit 28 converts a commercial AC power supply into a low voltage DC power supply and supplies power to the control circuit 30, the drive circuit 32, and the high voltage circuit 34.

The drive circuit 32 operates a drive unit 36 composed of a motor, a solenoid and the like in response to a command from the control circuit 30 to convey a sheet of recording material. The high-voltage circuit 34 supplies a high voltage to the image forming unit 42 according to a command from the control circuit 30 to form an image on the surface of the recording material. The control circuit 30 issues a command to the drive circuit 32, the high voltage circuit 34, and the exposure section 40, and also monitors the temperature of the fixing roller 56 by the thermistor 38 attached to the fixing roller 56 heated by the fixing heater 20 to drive the thyristor 18. And fixing heater 2
Control 0. Further, the control circuit 30 disconnects the relay 16 to stop the operation of the fixing heater 20 when it is not necessary to control the temperature of the fixing roller 56.

A sheet of recording material conveyed from the sheet feeding cassette 44 is sent to the image forming section 42. Image forming unit 42
Then, after the surface of the photosensitive drum 46 is charged by the charger 48, an electrostatic latent image which is an electric image is formed by the exposure unit 40, and then a corresponding portion of the electrostatic latent image is black by the developing cylinder 50. Attach toner. This toner image is transferred onto the paper conveyed from the paper feed cassette 44 by the transfer roller 5
The high voltage applied to the transfer roller 52 by being pressed by 2 is transferred to the sheet. In this state, the toner only adheres to the paper, is not fixed, and is unfixed. This sheet is conveyed to the fixing device 54. The fixing device 54 sandwiches the conveyed sheet with a fixing roller 56 and a pressure roller 58 to apply pressure. The fixing roller 56 is the fixing heater 2
The toner which is heated by 0 and adheres to the paper as an unfixed image is fixed on the paper by heat and pressure and fixed as a print image. The sheet on which the fixing has been completed is discharged to the outside of the apparatus through a path indicated by a conveyance path 60.

An example of installation of the page printer 70 is shown in FIG.
FIG. 3B shows the power supply path at that time. The first power cord 10 is connected to an outlet 68 to which commercial power is supplied, and the second power cord 22 is the outlet 6 of the personal computer which is the host device 62.
6 is connected. In this form, the switch 14 of the page printer 70 is used in a normally closed state.

When the power switch 64 of the host device 62 is off, power is supplied to the first power cord 10 and power is not supplied to the second power cord 22. Then, since power is not supplied to the power supply circuit 28, the power supply circuit 28 does not supply DC power to the control circuit 30. Therefore, the relay 16 and the thyristor 18 are not driven, and the electric power is not supplied from the power cord 10 to the fixing heater 20, so that the power of the entire page printer 70 is cut off. When the power switch 64 of the host device 62 is turned on from this state, power is supplied to the power supply circuit 28 via the second power supply cord 22, and the power supply circuit 28 operates to supply DC power to the control circuit 30.

The control circuit 30 operates the relay 16 and drives the thyristor 18 in order to control the fixing roller 56 to a temperature at which it can be fixed. As a result, electric power is supplied to the fixing heater 20 and the entire page printer 70 starts operating. Further, when the power switch 64 of the host device 62 is turned off from this state, the power supply to the second power cord 22 is stopped. As a result, power is not supplied to the power supply circuit 28, and the power supply circuit 28 does not supply DC power to the control circuit 30. Therefore, the drive of the relay 16 and the thyristor 18 is stopped, and the power to the fixing heater 20 is stopped.
The power of the entire page printer 70 is cut off.

When the power switch 64 of the host device 62 is turned on while the first power cord 10 is disconnected from the outlet 68, the control circuit 30 of the page printer 70 monitors the temperature of the fixing roller 56 by the thermistor 38 and detects the temperature. Try to control. However, since the power is not supplied to the power cord 10, even if the relay 16 and the thyristor 18 are driven, the power is not supplied to the fixing heater 20, and therefore the fixing heater 20 does not generate heat. Therefore, the first temperature is detected by the thermistor 38. It is possible to know that the power supplied to the power cord 10 has stopped. The same applies when the first power cord 10 is disconnected during operation and the supply of electric power is stopped.

[0016]

As is apparent from the above description,
According to the present invention, by operating the power switch of the host device, the power of the image forming device and the host device connected thereto can be operated in conjunction.

[Brief description of drawings]

FIG. 1 is an electrical schematic diagram of the page printer.

FIG. 2 is a schematic view of a cross section of the page printer.

FIG. 3A is a diagram showing an installation example of the page printer. (B) is a diagram showing a power supply path at that time.

[Explanation of symbols]

 10 First Power Cord 22 Second Power Cord 28 Power Circuit 30 Control Circuit 32 Drive Circuit 36 Drive Unit 54 Fixer

Claims (1)

[Claims] 1. An image forming apparatus in which a toner image is formed on a recording medium and the toner image is heated and fixed by a heating and fixing means, the first power supply being connected to an external power source and supplying electric power to the heating and fixing means And a second power supply unit that supplies power to the device control unit and the device drive unit other than the heat fixing unit, and when the power supply by the second power supply unit is stopped,
An image forming apparatus comprising: a control unit that stops the supply of power from the first power supply unit to the heat fixing unit.