JPH04338790A - Electrophotographic recorder - Google Patents

Abstract

PURPOSE:To improve the fixability with the constitution of the developing and fixing section of the electrophotographic recorder. CONSTITUTION:The temp. of the paper of a hopper 6 or near the pap is detected by a temp. sensor 10 of the electrophotographic recorder which is so constituted as to transfer the toner images formed on an image carrying member to the paper delivered from the hopper and heat-fixes the image by a heat fixing device. This temp. is regulated to the temp. suitable for fixing by a heat fixer 8 in a control circuit 15. The recorder is otherwise so constituted that a heating means for heating the paper is provided in the hopper or the waste heat of the heat fixer is introduced to the paper in the hopper to heat the paper.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a developing and fixing section of an electrophotographic recording apparatus.

0002

2. Description of the Related Art As shown in the schematic diagram of FIG. 4, an electrophotographic recording apparatus to which the present invention is applied uses an image carrier such as a photosensitive drum, which has a photosensitive layer on its surface whose conductivity changes in response to light. (hereinafter referred to as a photosensitive drum) 1, a developing device 2 that attaches toner to the drum surface by a potential difference with the surface of the photosensitive drum 1, a charger 3 that uniformly charges the surface of the photosensitive drum 1, and a scanning laser beam. an optical system 4 that changes the amount of charge on the photosensitive drum 1 to form an electrostatic latent image; a hopper 6 that stacks and stores papers 5; A transfer device 7 that transfers the image, and a heat fixing device 8 that includes a halogen lamp or the like that heats and fixes the transferred toner image onto the paper 5.
, a cleaning device 9 that removes and collects toner remaining on the surface of the photosensitive drum 1, and the like.

The heat fixing device 8 maintains a constant temperature regardless of the ambient temperature, or controls the temperature depending on the outside temperature of the apparatus.

0004

[Problem to be Solved by the Invention] The heat fixing device maintains its temperature as described above, but if the temperature is kept constant regardless of the ambient temperature, if the outside temperature is low, it will depend on the cooled paper. There was a problem in that heat was taken away and there was insufficient energy to fix the toner image, resulting in a low fixing rate.

On the other hand, in the method of controlling the temperature of the heat fixing device depending on the outside air temperature of the apparatus, the paper temperature and the outside air temperature do not necessarily match. For this reason, even if the outside temperature is low, the paper temperature may be sufficient, and in this case, energy for heating the heat fixing device is wasted.

[0006]Also, even if the outside temperature is high, paper that has been stored in a cool place may be used, and in this case there is a problem that there is insufficient energy to heat the heat fixing device, resulting in poor fixing. there were.

The object of the present invention is to improve the fixing rate.

[0008]

[Means for solving the problem] In the present invention, FIG.
As shown in the block diagram, there is a temperature sensor 10 that detects the temperature of the paper 5 in the hopper 6 or the vicinity of the paper, and a control that adjusts or reduces the temperature of the heat fixing device 8 according to the temperature detected by the temperature sensor 10. The circuit 15 has a circuit 15.

Alternatively, as shown in the schematic diagram of FIG. 2, the hopper 6 has a heating means 11 for heating the paper 5, or
As shown in the schematic diagram of FIG. 3, a means 19 is provided for guiding the waste heat of the heat fixing device 8 to the paper 5 in the hopper 6.

0010

[Operation] By measuring the temperature of the paper or the vicinity of the paper,
The temperature of paper in the hopper can be detected with high accuracy.

[0011] Therefore, the temperature of the heat fixing device can be properly controlled by the control section. Further, by heating the paper in the hopper with waste heat from the heating means or the heat fixing device, the temperature of the paper increases, and good fixing is possible even if the temperature of the heat fixing device is constant.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, as shown in the block diagram of FIG.
Alternatively, the temperature near the paper is detected by the detection circuit 12.

This value is sent to a comparator circuit 13, where it is compared with a threshold value 14 that sets the appropriate paper temperature, and is then sent to a control circuit 1.
Sent to 5. The temperature of the heat fixing device 8 is also input to the control circuit 15 through a temperature sensor 16 and a detection circuit 17.

Therefore, when the control circuit 15 determines that the temperature of the paper 5 is lower than the threshold value 14 and that the temperature of the heat fixing device 8 cannot cope with this temperature, the control circuit 15 controls the heat fixing device 8 by using the heating circuit 18. Heat further.

Further, when it is determined that the temperature of the paper 5 is higher than the threshold value 14 and the temperature of the heat fixing device 8 is also sufficient, the temperature of the heat fixing device 8 is
control the temperature so that it is lower than the set temperature. The schematic diagram of FIG. 2 shows another first embodiment, in which a heating means 11 comprising, for example, an array of incandescent bulbs or a heater is provided so as to face the paper 5 in the hopper 6, and the power is 30 to 60W.
Heat the paper 5 with.

Then, even if the temperature of the thermal fixing device 8 is not controlled and remains constant, the temperature of the paper 5 rises, making it possible to perform good fixing. The schematic diagram in FIG. 3 shows another second embodiment, in which the waste heat of the heat fixing device 8 is transferred to a duct 19 and a fan 2.
0 is used to guide the paper 5 in the hopper 6 and heat it.

[0017] Accordingly, the same effect as that shown in FIG. 2 described above can be obtained. That is, in the case of FIG. 1, the temperature of the paper 5 in the hopper can be detected with high accuracy, the temperature of the thermal fixing device 8 can be more appropriately controlled, and waste of heating power can be avoided.

In addition, in the case of FIGS. 2 and 3, the heating means 1
1, or the paper 5 in the hopper 6 is heated by the waste heat of the heat fixing device 8, and the temperature of the paper 5 rises, causing the heat fixing device 8 to heat the paper 5.
Good fixing is possible even if the temperature is constant.

[0019]

[Effects of the Invention] According to the present invention, the thermal fixation rate of toner images on paper is improved, wasteful consumption of electric power can be prevented, and the heating time of the thermal fixing device is shortened, so warming up after turning on the power is improved. It has great economic and industrial effects, such as shortening the time.

[Brief explanation of drawings]

FIG. 1: Block diagram of an electrophotographic recording device of the present invention,

FIG. 2 Another first schematic diagram of the electrophotographic recording device of the present invention,

FIG. 3 Another second schematic diagram of the electrophotographic recording device of the present invention,

FIG. 4 is a schematic diagram of an electrophotographic recording device to which the present invention is applied;

[Explanation of symbols]

5 Paper, 6 Hopper, 8　Heat fixing device, 10, 16 Temperature sensor, 12, 17 detection circuit, 13 Comparison circuit, 14 Threshold value, 15 Control circuit, 18 Heating circuit, 19 Duct, 20 Fan,

Claims (3)

[Claims] Claim 1: An electrophotographic recording device in which a toner image formed on an image carrier (1) is transferred from a hopper (6) to a sheet of paper (5) and is heated and fixed by a heat fixing device (8). In the hopper (6), a temperature sensor (
10); and a control circuit (15) for controlling the temperature of the heat fixing device (8) according to the temperature detected by the temperature sensor (10). . [Claim 2] The hopper (6) of Claim 1 is a paper (
5) An electrophotographic recording device characterized by having a heating means (11) for heating. 3. Means (19) for guiding the waste heat of the heat fixing device (8) of claim 1 to the paper (5) in the hopper (6).
) An electrophotographic recording device characterized by having: