JPS60159869A - Developing device - Google Patents

Abstract

PURPOSE:To enable development small in humidity variation and stable in image quality by installing a developing vessel provided with a magnet roll in the inside and a heating means for humidifying the inside of the vessel. CONSTITUTION:When a humidity detector 12 installed inside a developing vessel 5 or near its outside detects low humidity, a detection signal is compared in a signal processing unit 14, and actuates the heater of a humidifier 13. Steam produced from heater water 15 is introduced into the vessel 5 through a pipe 16 to humidify the inside. A developer 8 is humidified with the steam, and image density is enhanced. When humidity corresponding to the optimum image density is caused to be stored in the unit 14 in advance, humidificationof the humidifier 13 is stopped by detecting the optimum humidity by the detector 12, and the inside of the vessel 5 is maintained always at constant humidity. When the detector 12 detects high humidity, the detection signal is compared in the unit 14, and the heater 17 of a heating means is actuated. Accordingly, the inside of the vessel 5 and the developer 8 are dried, and the heating means is stopped when humidity reaches the optimum humidity.

Description

DETAILED DESCRIPTION OF THE INVENTION - Industrial Application Field The present invention relates to a developing device that can be used, for example, in electrophotographic copying machines and facsimile machines.

Conventional configuration and its problems Electronic copying machines require the steps of charging the photoreceptor, image exposure, and development.
The process mainly consists of a step of transferring the image onto paper, a step of separating the paper from the photoreceptor, a step of fixing the separated paper, and a step of cleaning the untransferred developer.

FIG. 1 shows a block diagram of the main parts of a conventional copying machine. In the figure, reference numeral 1 denotes a drum-shaped photoreceptor that rotates in the two directions of arrows. A charger 3 applies high voltage to give static electricity to the surface of the photoreceptor 1. Arrow 4 indicates image exposure, and an electrostatic latent image is created by this exposure. 5 is a developing container, a magnet roll 6,
It is composed of a stirring rod 7. Developer container 6 contains developer 8.
is stored. 9 is a charger for transfer, and 10 is a charger for paper separation. Reference numeral 11 denotes a cleaning means 0. The photoreceptor 1 is charged with static electricity by the charger 3, receives image exposure 4, and is developed by the developer 6. The developed image is transferred to paper by a transfer charger, the paper is separated from the photoreceptor 1 by a paper separation charger 10, and the paper is fixed by a fixing device (not shown) to make a copy. The photoreceptor 1 is cleaned by a cleaning means 11 and is reused.

The developer 8 is composed of carrier and toner. The carrier is made of iron powder or ferrite powder with a size of about 100 to 400 meshes, and the surface thereof is coated with a polymer. The toner consists of colored resin powder with an average particle size of 8 to 16 microns. The carrier and toner are stirred by a stirring rod 7 within the developer container 6, and are frictionally charged and charged with static electricity.

The electrical resistance of the developer 8 has an effect on image characteristics; if the electrical resistance decreases, the image will have a high density of black areas with little etch effect, but if the electrical resistance increases, the image will have a low density with a large edge effect. On the other hand, since the developer 8 is a fine powder, it is significantly affected by changes in the environment. In other words, under high humidity conditions, images will have high image density, but under low humidity conditions, images will have low image density. Therefore, in order to obtain a constant image regardless of environmental conditions, exposure to light is required under low humidity conditions. The surface potential of the body 1 was set high, and the mixture ratio of toner and carrier in the developer 8 was set to be large. In addition, when the humidity was high, the surface potential of the photoreceptor 1 was lowered, and the toner to carrier mixing ratio in the developer 8 was set to be lower. However, if the surface potential is changed depending on the humidity, the carrier will adhere to the image and damage the photoreceptor 1, and if the mixing ratio of toner and carrier is changed depending on the humidity, it will not be able to respond to sudden changes in humidity. .

OBJECTS OF THE INVENTION The present invention aims to eliminate the drawbacks of the above-mentioned conventional examples, and provides a developing device that is capable of developing images with stable image quality with little change in humidity.

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention comprises a developing container equipped with a magnetic roll inside and a humidifying means for the inside of the developing container, thereby reducing the humidity inside the developing container. is always kept constant.

Description of examples Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a configuration diagram of the main parts of the electronic copying machine of the present invention. In the figure, 1 is a photoreceptor, 2 is its rotation direction, 3 is a charger,
4 is image exposure, 6 is developer container, 6 is magnet roll, 7
is a stirring rod, 8 is a developer, agent, 9 is a transfer charger, 1o is a paper separation charger, and 11 is a cleaning means, which are the same as those used in the explanation of Figure 1 and have the same effect. . Reference numeral 12 denotes a humidity detector, and even if it is inside the developer container 5,
It may be in the vicinity of . Reference numeral 13 denotes a humidifier, which is connected to the developer container 6 by a hydraulic pipe 16. 17 is a heater. Reference numeral 14 denotes a signal processing section, which operates the humidifying device 13 and the fttri heater 17 in accordance with the signal from the humidity detecting means 12. 15 is water.

Next, the operation of the present invention according to the above configuration will be described. When the humidity detector 12 disposed inside or near the outside of the developer container 6 detects a low humidity state, the detection signal is compared and processed in the signal processing section 14. , the heater (not shown) of the humidifier 13 is activated. The water vapor generated from the heated water 16 is sent from the pipe 16 into the developing container 5 and humidified, causing the developer 8 to absorb moisture and increase the image density.The humidity at the optimum image density is determined by signal processing in advance. Part 1
4, the humidification by the humidifier 13 is stopped when the humidity is detected by the humidity detector 12, and a constant humidity is always maintained in the developer container.

Note that this humidification operation may be performed automatically with the above-described configuration, but may also be performed manually when the image density decreases at low humidity.

Toe 9: The humidity inside the developing device is generally lower than the environment in which the copying machine is used due to the effects of heat from the lighting of the exposure lamp, heat generated by the fixing device, and a dew prevention heater. At this time, the developer is also in a low humidity state, so even if you simply send water vapor generated from a humidifier connected to the developer container 6 with a hand pump and humidify it, the optimum humidity will not be reached. It is also possible to humidify the developer container by simply feeding water vapor into the developer container using a hand pump or the like. In this case, humidity detection means and heating means in the developing container are not required.

When the humidity detector 12 detects a high humidity state, the signal processing unit 1
4, the comparison process is performed, and the heater 17 of the heating means is activated. Therefore, when the inside of the developer container 5 and the developer 8 are dried and the humidity reaches the optimum level, the heating means is stopped.

As described above, the present invention operates a humidifying means or a heating means in response to a humidity detection signal from a humidity detector to maintain a constant humidity inside a developing device, thereby enabling development with stable image density. ing.

Although the humidifying device described above is connected to the outside of the developing device via a pipe, the humidifying device is not limited to this, and can easily be provided integrally inside the developing container.

Effects of the Invention As is clear from the above description, the present invention includes a humidity detection means, a heater, and a humidification means inside or near the developing device, and by keeping the internal humidity of the developing device constant at all times, electronic A stable image can always be obtained without being affected by the environment in which the copying machine is used.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the main parts of a conventional copying machine, and FIG. 2 is a diagram showing the main parts of a copying machine according to an embodiment of the present invention. magnet roll,
7...Stirring rod, 8...Developer, 12.
Music/humidity detector, 13...humidifier, 14/river...signal processing section, 15...water 1.17...
heater.

Claims (2)

[Claims] (1) A developing device that is completely equipped with a developing container in which a magnetic roll is arranged, and a humidifying means for humidifying the inside of the developing container. (2) A humidity detecting means, a heating means, and a humidifying means are disposed inside the developing container or in the vicinity of the developing container, and the heating means or the humidifying means are operated in accordance with a signal from the humidity detecting means. A developing device according to claim 1.