JPH0324581A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the lowering of the voltage of a power source during image exposure lowering by inhibiting turning on a heater which heats a thermal fixing means during the image exposure. CONSTITUTION:During the image exposure incidence, turning on the heater 2 which heats a fixing means 1 is inhibited. That is, when the detected temperature (t) of a temperature sensor 3 mounted on a fixing roller rises above the set temperature T1 of an upper limit temperature setting means, a heater lamp 2 is turned off. When the detected temperature (t) drops below the set temperature T2 of a lower limit temperature setting means, the heater lamp 2 is directly turned on if the projecting lamp 5 of an image exposure device 4 is not lighted; otherwise, the heater lamp 2 is turned on after the projecting lamp 5 is turned off. Thus, it is prevented that the light quantity shortage of image exposure and fluctuation in the rotation of an image forming body 6 during the image exposure, etc., occur from the deterioration of a power source voltage caused by turning the heater on.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image forming apparatus such as an electrophotographic copying machine or an electrophotographic recording apparatus, that is, an image forming apparatus in which an image is formed by injecting image exposure onto the charged surface of an image forming body. The present invention relates to an image forming apparatus that develops an electrostatic image into a toner image, transfers the toner image onto a transfer material, and fuses the toner image with a heat fixing means.

[Conventional technology]

In the conventional image forming apparatus as described above, which uses a fixing roller having a heater lamp inside as a heat fixing means, the temperature of the fixing roller is controlled by turning on the heater lamp and detecting the temperature by a temperature sensor provided on the fixing roller. When the temperature exceeds the upper limit temperature, the heater lamp is turned off, and when the temperature detected by the temperature sensor falls below the lower limit temperature, the heater lamp is turned on, regardless of the incidence of image exposure on the image forming body surface. . Therefore, the heater lamp is often turned on during image exposure, and the maximum power required for the entire image forming apparatus is 1.4 to 1.4 l. The output of the heater lamp is about 850" 1100W, whereas it is about 5Kw.
When the heater lamp is turned on during image exposure, the voltage of the power supply temporarily drops, resulting in insufficient light intensity for image exposure, fluctuations in the rotation of the image forming body, etc., and the quality of the image formed and recorded deteriorates. There was a problem when it came to doing so.

[Problem to be solved by the invention]

The present invention has been made in order to solve the above-mentioned problems, and provides an image forming control device in which the power supply voltage does not drop due to turning on of the heater lamp during the image exposure incident on the image forming body. For the purpose of providing.

[Means to solve the problem]

The present invention provides an image forming device that develops an electrostatic image formed by applying imagewise exposure onto a charged surface of an image forming body into a toner image, transfers the toner image onto a transfer material, and fuses the toner image with a silent fixing means. In this case, switching on the heater for heating the fixing means is prohibited during the image exposure period! The present invention provides an image forming apparatus having the following features, and achieves the above object with this structure.

[Effect]

That is, since the image forming apparatus of the present invention prohibits the heater from being turned on during image exposure,
A drop in power supply voltage caused by switching on the heater will not cause insufficient light for image exposure or fluctuations in the rotation of the image forming body during image exposure, so images of good quality are always formed and recorded stably. be able to.

〔Example〕

The present invention will be explained below using illustrated examples.

FIG. 1 is a schematic structural diagram showing an example of an image forming apparatus of the present invention in which the fixing means is a fixing roller having a heater lamp inside;
FIG. 2 is a chart showing seven control points of the control device regarding the temperature control of the fixing roller.

In this image forming apparatus, when the power switch is turned on, that is, the power is turned on, the control device turns on the heater lamp 2 inside the fixing roller of the fixing device L, and then the temperature detected by the temperature sensor 3 installed on the fixing roller is controlled. When t becomes higher than the set temperature TI of the temperature setting means, the heater lamp 2 is turned on.
7, and when the detected temperature becomes lower than the set temperature T2 of the lower limit temperature setting means, the projection lamp 5 of the image exposure device 4 is turned off.
If the projection lamp 5 is not lit, turn on the heater lamp 2 immediately, or if the projection lamp 5 is lit, after it is turned off.
The fixing roller temperature is controlled when the power switch is turned on, and the control ends when the power switch is turned off. therefore,
It is said that the reduction in the power supply voltage due to turning on of the heater lamp 2 occurs during the incidence of image exposure onto the image forming body 6, and as a result, the quality of the toner image formed on the image forming body 6 becomes inferior. Things disappear.

To form an image in this image forming device, when the power switch is turned on and the temperature of the fixing roller of the fixing device 1 exceeds a predetermined temperature, the control device controls the image forming body 6. A pulse signal is input from the rotary encoder 7 which is rotated in the direction of the arrow, thereby rotating integrally with the image-shaped body 6, and based on the signal, the cleaning device 8. Charger9. Projection lamp 5
An image exposure device 4, a developing device 10. 1,000 stages of recording paper feed, transfer device 12. Separator 13. Transport means 14. This is done by driving the fixing device 1, the rotating means for the paper ejection roller 15, and the like. Therefore, information on whether or not the projection lamp 5 is lit can be obtained within the control device without using any particular detection means.

The image forming apparatus of the present invention is not limited to the illustrated example in which the image exposure device projects light from a document directly onto an image forming body, but the image forming device reads image information with a document reading device and uses a laser beam scanner to form an image based on the information. It may also be one in which dot image exposure is applied to the body. In that case, if the document reading and image exposure are performed in real time, the same effect as in the case of a slit exposure image forming device can be obtained; Since rotational fluctuations in the rotational speed are reduced, a considerable effect can be obtained.

Furthermore, the present invention is not limited to a fixing roller having a heater inside the fixing means.

〔Effect of the invention〕

In the image forming apparatus of the present invention, the heater is turned on during image exposure, and the power supply voltage decreases, which changes the amount of light for image exposure and the rotation of the image forming body, resulting in a change in the formed image. Since no deterioration in quality can occur, the effect of stably forming a good image can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of the image forming apparatus of the present invention, and FIG. 2 is a control flowchart of a control device for temperature control of a fixing roller. l... Fixing device 2... Heater lamp 3.
...Temperature sensor 4...Image exposure device 5...Projection lamp 6...Image-shaped body 1 Figure 2

Claims (1)

[Claims] In an image forming apparatus that develops an electrostatic image formed by applying imagewise exposure onto a charging surface of an image forming body into a toner image, transferring the toner image to a transfer material and fusing it by a heat fixing means, An image forming apparatus characterized in that switching on of a heater for heating the heat fixing means is prohibited.