JPS6151165A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To dehumidify a photosensitive body and prevent an image from becoming unsharp owing to moisture absorption by driving an air supply fan on the basis of the signal of a humidity detector provided nearly the surface of the photosensitive body and guiding heated air nearby a fixing device to the surface of the photosensitive body. CONSTITUTION:The humidity detector 31 is provided nearby the surface of the photosensitive body 1 and the air supply fan 32 is arranged in an air duct 30 at the upper part of a fixing roller 13. Decomposed products, ozone, etc., stick on the surface of the photosensitive body during image formation and moisture is easy to absorb. When the detected humidity of said humidity detecting means 31 attains to a specific value, the air supply fan 32 is driven with its detection signal to blow heated air nearby the fixing device to the surface of the photosensitive body, which is dehumidified. Thus, the formation of an unsharp image due to the moisture absorption of the photosensitive body is prevented.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to an electrophotographic apparatus.

[Technical blue application of the invention and its problems] Electrophotographic devices such as electronic copiers and laser printers have built-in electrophotographic photoreceptors, and this electrophotographic photoreceptor retains the charge caused by corona discharge for a predetermined period of time. ．． Either electrons or hole pairs generated by imagewise exposure have the function of neutralizing surface charges.

Due to this function, the surface of the electrophotographic photoreceptor is charged with butter.
A pattern is formed, which is visualized by attaching a developer charged with the opposite polarity to the charge pattern, and then by transferring the developer that makes up the visible image onto a recording medium such as paper. Image formation is performed.

The above-mentioned electrophotographic photoreceptor is SC type, Sc-Te
Materials such as 3C series, ZNO series, and OPC are used, but 3C series and 5e-Te series have low hardness, short lifespan, and are harmful to the human body and have a low softening point.
What problems are there? ZnO-based materials have problems with printing durability, and OPC has poor printing durability. There is a problem that P-life is unknown.

For this reason, amorphous silicon has recently been used for electrophotographic photoreceptors. Electrophotographic photoreceptors using this amorphous silicon have a wide absorption wavelength range, full color alignment, and high sensitivity. Moreover, it has advantages such as high hardness, a lifespan ten times longer than conventional ones, and a high glass transition point of 300° C. or higher and excellent heat resistance.

By the way, an electrophotographic photoreceptor using amorphous silicon itself has the property of not easily absorbing moisture, but during corona charging, organic matter decomposed in the atmosphere and ozone easily adhere to its surface. Foreign matter that has adhered to the electrophotographic photoreceptor absorbs moisture in a humid atmosphere, causing a change in the resistance value of the surface of the electrophotographic photoreceptor.As a result, the electric potential on the surface flows toward the surface, resulting in a problem that the formed image becomes unclear. Incidentally, the same problem in a humid atmosphere occurs even when an electrophotographic photoreceptor using a photoconductive material other than amorphous silicon is used.

[Object of the Invention] The present invention has been made in view of the above-mentioned circumstances, and its object is to prevent defects in formed images due to moisture absorption of an electrophotographic photoreceptor. ! 1. Electrons that can be prevented from becoming bright
J't° (There is a need to provide equipment.

1. Main points of the invention] In order to make a target, the electrophotographic apparatus according to the present invention forms an electric charge pattern on the surface of an electrophotographic photoreceptor, and applies this electric charge pattern to a developing agent. At the same time as visualizing the image (((), an electrophotographic apparatus is installed in an electrophotographic apparatus that transfers an agent to a recording medium and fixes it with a heating type fixing means to form an image, and the electrophotographic photosensitive material is An air supply duct passing near the surface of the body, a temperature detection means for detecting the humidity on the surface of the electrophotographic photoreceptor, and heated air near the heating type fixing means based on a detection signal from the humidity detection means. By providing an air supply means in the air supply duct, when the humidity of the body surface reaches a predetermined value, heated air near the heating type 11 means is supplied to the surface of the electrophotographic photoreceptor. It is designed to dehumidify by spraying it on.

[Embodiments of the invention] Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention. The apparatus of this embodiment has an electrophotographic photoreceptor (hereinafter also simply referred to as photoreceptor) 1 in a housing 15, on which a charge pattern is formed. For example, this is made by depositing a photoconductive material such as amorphous silicon on the surface of a conductive drum. A charger 2 is arranged above the photoreceptor 1 to charge the surface of the photoreceptor. In order to imagewise expose the surface of the photoreceptor 1 charged by 2 with this charger, arrow A1. A document platen glass 3 that reciprocates in the Δ2 direction, an exposure lamp 5 such as a halogen lamp that irradiates light onto the document 4 thereon, and a lens 6 that images reflected light from the document onto the surface of the photoreceptor 1 are provided. It is being A charge pattern is formed on the imagewise exposed surface of the photoreceptor 1, and a developing device 7 is disposed at the front along the rotational direction of the photoreceptor 1 to apply a developer to the charge pattern and visualize it. On the other hand, a paper feed cassette 9 containing a recording medium such as paper 8 is provided below the developing device 7, and the top layer of paper 8 can be taken out via a paper feed roller 10. The removed t418 is
The photoreceptor 1 is aligned by the registration rollers 11, and is transported forward in time with the rotation of the photoreceptor 1 in the direction of the arrow. When the paper 8 has been conveyed to a position where it contacts the surface of the photoreceptor 1, the visible image has been conveyed to a position opposite to the paper 8 by the rotation of the photoreceptor 1, and a visible image is formed. The developer is transferred onto the paper 8 via a transfer device 12. A fixing roller 13 having a built-in heater in one roller is provided as a heating type fixing means for fixing the transferred developer onto the paper 8, and a discharge paper 1-ray 14 that receives and takes the paper P after fixing is provided at the other end of the fixing roller 13. It is located in

On the other hand, in addition to the transfer by the transfer device 12, a static eliminating charger 16 is disposed to eliminate static electricity from the surface of the photoreceptor 1, and the surface of the photoreceptor 1 is further cleaned by removing developer remaining on the surface of the photoreceptor 1. A cleaner 20 and a static elimination lamp 21 are provided to scrape off residual developer from the surface by touching the surface.

In order to dehumidify the surface of the photoreceptor 1, an air supply duct 30 communicating from the vicinity of the fixing roller 3 to the vicinity of the surface of the photoreceptor 1; and a humidity detection means 31 for detecting the humidity on the surface of the photoreceptor 1; Based on the detection signal from the humidity detection means 31, the heated air near the fixing roller 3 is transferred to the air supply duct 1.
An air supply fan 32 is provided as an air supply means for supplying air to the photoreceptor 1, and when the humidity on the surface of the photoreceptor 1 reaches a predetermined value, the heated air near the fixing roller 3 is blown onto the surface of the photoreceptor 1. It is attached to dehumidify. In addition, since this device directly blows heated air onto the surface of the photoreceptor 1, it is difficult to use materials such as amorphous silicon, which has a high glass transition point of 300°C or higher and does not undergo irreversible changes at temperatures below that temperature. It is desirable to use it as a photoconductive material. Further, the position at which the heated air is blown by the air supply tact 30 must be between after cleaning and before the phenomenon occurs in the rotational direction of the photoreceptor 1. During this time;□
This is because the developer is not attached to the surface of the photoreceptor 1 and the developer is not melted and attached to the surface of the photoreceptor 1 by the heated air. Furthermore, a January air vent 33 is provided on the side of the housing 15.

Next, the operation of the above embodiment device θ will be explained.

The surface of the front photoreceptor 1 is charged by a charger 2, and the charged surface t is imagewise exposed to light reflected from the original document 4 to form a charge pattern. This charge pattern is conveyed as the photoreceptor 1 rotates in the direction of the arrow, and during the conveyance, a developer is attached to it by a developing device 7 and visualized. On the other hand, the paper 8 is taken out from the paper feed cassette 9 and is timed with the conveyance of the visible image via the register 1-roller 11.

When the paper 8 reaches the top of the transfer device 12, the developer constituting the above-mentioned image is transferred onto the paper 8.

The developer that has been transferred is fixed on the paper 8 by the fixing roller 13, and the paper 8 is discharged to the paper discharge tray 14. On the other hand, during the transfer process, the surface of the photoreceptor 1 is neutralized by the static elimination cooler 16, and some remains on the surface]L! The 4% agent is removed by a cleaner 20, and the entire surface of the photosensitive body 1 is exposed to light by a static elimination lamp 21, and the photosensitive body 1 is returned to the starting position of the image forming operation to wait for the next instruction to start the operation. On the other hand, since corona discharge occurs in the charger 2 and transfer device 12 during the image forming operation, there may be tobacco tar, bacteria, etc. floating in the air around them (genuine products decompose due to the corona discharge, and this decomposition occurs). Although products such as ozone and the like adhere to the surface of the photoreceptor 1 and are likely to absorb moisture, the humidity on the surface of the photoreceptor 1 is always detected by the humidity detection means 31, so the humidity on the surface of the photoreceptor 1 is When it reaches a predetermined value, the air supply fan 32 is driven based on the detection signal.As a result, the heated air near the fixing roller 13 is blown onto the surface of the photoreceptor 1 through the air supply duct 30. The surface is dehumidified.Moreover, as shown in Figure 2, the heated air is
Since the heated air is guided and blown near the surface of the photoreceptor 1 through the photoreceptor 30, the heated air can reliably dehumidify the entire circumferential surface of the photoreceptor without stagnation near the photoreceptor.

Therefore, even in a humid atmosphere, the resistance value of the surface of the photoreceptor 1 does not change, and the potential on the surface does not flow toward the surface, making it possible to form a clear image.

It should be noted that the above-mentioned embodiment is merely an example, and it is obvious that various modifications can be made within the scope of the gist of the present invention. For example, the air supply duct 1- is limited to a grooved type with its outlet located in the center of the photoreceptor, but may have any suitable shape such as a shape that allows air to be emitted from the entire surface along the axial direction of the photoreceptor. can.

[Effects of the invention] As is clear from the above 1.
, T, the device can prevent the formed image from becoming unclear due to moisture absorption of the electrophotographic photoreceptor.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an apparatus according to an embodiment of the present invention, and FIG. 2 is a top view for explaining the operation of the apparatus according to the embodiment. 1... Electrophotographic photoreceptor, 8... Recording medium, 13... Heating constant volume means, ~ 30... Air supply duct [..., 31 ... Humidity detection means, 32 ... Air supply means.

Claims (1)

[Claims] In an electrophotographic device that forms an electric charge pattern on the surface of an electrophotographic photoreceptor, visualizes this electric charge pattern with a developer, transfers the developer to a recording medium, and fixes it with a heating type fixing means to form an image. , an air supply duct passing from the vicinity of the heating type fixing means to the vicinity of the surface of the electrophotographic photoreceptor, a humidity detection means for detecting the humidity on the surface of the electrophotography photoreceptor, and a detection signal from the humidity detection means. An electrophotographic apparatus further comprising an air supply means for supplying heated air near the heating type fixing means to the air supply duct.