JPS6242172A - Image forming device - Google Patents

Abstract

PURPOSE:To suppress scattering of a developer, etc., and to remove discharge products such as ozone produced in electric discharging efficiently by making the velocity of an air flow generated by a forcible ventilating means different during image formation from during image nonformation. CONSTITUTION:An electric discharging electrode 3a is surrounded with a shield member 3b which has a discharge opening and a ventilating hole 3c, a duct 3d, and air flow fan 3e are provided on the back surface of the member 3b. A control part 9 is connected to the fan 3e to make the velocity of the air flow generated by the fan 3e different when an illumination lamp 8c scans an original 6 (exposure) from when the illumination lamp 8c returns to the home position at the front end of the original (nonexposure). The blow flow velocity by the fan 3e is reduced in the exposure to prevent the discharging electrode 3e of an electrostatic charging part 3 from being stained, or increased in nonexposure to remove ozone produced in the discharging.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an image forming apparatus that suppresses the occurrence of image blur.

<Conventional technology> Conventional image forming devices have a charging section around the photoreceptor.

An exposing section, a developing section, etc. are arranged in this order, and the charging section uniformly charges the photoreceptor, the exposing section forms an electrostatic latent image, and the developing section develops the RKm image. A recorded image is obtained by transferring the image to a predetermined sheet.

In the above-mentioned devices that use an organic photosemiconductor as a photoreceptor, a functionally separated type in which a charge generation layer and a charge transport layer are provided on a conductive substrate is often used.

<Problems to be Solved by the Invention> The above-mentioned photoreceptor using a hydrazone compound as the charge transport layer has a hydrazone structure with poor ozone resistance.
There is a problem in that it deteriorates due to ozone generated during charging, resulting in blurred images.

For this reason, if a protective layer resistant to ozone deterioration is provided on the surface of the photoreceptor, the residual potential of the photoreceptor layer will increase. Further, if ozone is removed by forced ventilation from the back side of the charging section, good results can be obtained in terms of image blurring, but there are problems such as uneven discharge and scattering of developer due to forced ventilation.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to provide an image forming apparatus that reduces ozone deterioration of a photoreceptor and uneven discharge of a charging section.

Means for Solving the Problems> Means of the present invention for solving the above problems is that in an image forming apparatus using a charging device having forced ventilation means, the air flow rate due to the forced ventilation means is lower than that during image formation. The feature is that the structure is different depending on when it is formed and when it is not formed.

According to the above means, by efficiently operating the forced ventilation means, it is possible to prevent the discharge electrode from being contaminated by developer, etc. when an image is being formed, and to remove ozone generated by discharge when an image is not being formed. It is something that can be done.

<Example> Next, an example in which the above means is applied to an electrophotographic apparatus will be described.

The first part is a schematic explanatory diagram of an electrophotographic apparatus, in which a pre-exposure section 2 for neutralizing the electric charge on the photosensitive layer of the drum 1, a pre-exposure section 2 for neutralizing the charge on the photosensitive layer of the drum 1, and a surface area of the photosensitive drum 1, which forms a photosensitive member, are provided. One+
A charging unit 3 performs charging, an exposing unit 4 converts the image written on the draft into an electrostatic latent image, a developing unit 5 develops the electrostatic latent image into a visible image, and transfers the visible developed image onto a predetermined sheet. Transfer section 6,
Cleaning section 7 that cleans the tram l after transfer
are arranged in order of people.

In addition, 11;
An illumination lamp 8c is provided to scan the original 8b placed on the original platen 8a from left to right in the drawing.
It is configured to transmit the reflected light to the exposure section 4 via a plurality of mirrors 8d and lenses 8e.

Furthermore, the charging section 3 is constructed by surrounding a discharge electrode 3-1 made of a wire connected to a high-voltage power source with a shield member 3b that protects the discharge opening.
A ventilation port 3c is provided on the back side of b, and the ventilation port 3
A duct) 3d is connected to c, and an airflow fan 3e is installed in the duct 3d to constitute forced ventilation means.

...The control section 9 is connected to the roughan 3C described in j, and the control section 9 is connected to the control section 9.
While the illumination lamp 8c is scanning the original 6 (during exposure) and while the illumination lamp 8c returns to the home position at the leading edge of the original (on the left side of the original in the drawing) (during non-exposure), the fan 3e blows air. It is configured to be able to change the flow rate.

When using the apparatus configured as described above, the air velocity by the fan 3e is reduced during exposure to prevent contamination of the discharge electrode 3a of the charging section 3, and the fan 3e is reduced during non-exposure.
The ozone generated during discharge can be removed by increasing the air flow rate.

Next, the results of an experiment in which a copying process was executed using the apparatus having the above configuration will be explained.

Recommended diameter is 80mm and length is 2 as the photosensitive drum 1 which becomes the photosensitive member.
60 cranes, wall thickness 1. Aqueous ammonia solution of casein on Ol- aluminum cylinder? flc casein 11.2g,
1 g of 28% ammonia water 1 222 m of water (1) was applied by dipping and dried to form an adhesive layer with a coating amount of i and ogzm2, and then a disazo pigment 5 having the structure shown in Fig. 2 was applied.
g and 2 g of butyral resin (degree of butyralization 63 mol%)
The mixture was poured into 95 ml of ethanol and alcohol. night and -ij
(Coating on the adhesive layer to form a charge generation layer with a coating weight of 0.23/m'' after drying 1-1 P as the charge transport material 2; ethylamino 5 g of henzaldehyde α-naphthylphenylhydrazine, binder and acrylic-styrene resin (MS-200, Prayer F'l)
Iron chemistry) 5g to monochlorhenzene 150m6) Volume j
l'+u da7& was coated on the charge generation layer and dried to form a poison transport layer with a coating weight of 10 g/m2.

Experiment J When obtaining an electrostatic latent image with the photosensitive drums J and l, while the illumination lamp 8c scans the original JFi 8b, the bulb 3
From 3e, the illumination lamp 8c is blown to scan the document i? The wind speed was set at 5 m/s during the time from the end of the original to the home position at the leading edge of the original, and 30,000 copies were continuously made on A4 size sheets, but no image blurring due to ozone deterioration occurred. .

On the other hand, when copies were made continuously in the same manner as in the past without any forced ventilation, the image became blurry after about 3,000 copies, and the copied image deteriorated after about 5,000 copies. At iJ
I can no longer distinguish the characters.

Furthermore, as in the past, the above-mentioned strong:Thl ventilation is illuminated with a lamp 8C.
When the wind speed was set to be constant regardless of the left side and non-scanning (in this experiment, the wind speed was set to 5 m/s), the discharge electrode 3a of the charging section 3 was easily contaminated by the developer flying 1fk, and the air flow rate was approximately 5,000 m/s.
When the number of sheets was 0, image unevenness occurred, and staining of the inside of the ring 7 photographic device due to the developer was also noticeable.

Experiment 2 Next, the copying process was carried out in the same manner as in Experiment 1, with the fan 3c not blowing air while the illumination lamp 8c was scanning, and the control unit 9 controlling the lamp 8c to blow air when the scanning was completed. Although slight image blurring occurred after approximately 20,000 sheets, it was considerably more effective than the conventional example.

Experiment 3 If the illumination lamp 8c in Experiment 1 was not charged by the charging unit 3 between the end of scanning and the start of the next scanning, no image blurring occurred even after 50,000 sheets were printed. .

Experiment 4 When copies were made in the same manner as in Experiment I by reversing the rotation of the fan 3e and directing the ventilation direction 1iiT from the charging section 3 to the fan 3e, no image blurring occurred even after 30,000 copies. Ta.

Experiment 5 Next, while the illumination lamp 8c is scanning, the charging section 3 is
Air is blown in the direction at a speed of 1 m/s, and after the scanning is completed, the charging part 3
I so that the wind speed is 5 m/s from
When copies were made in the same manner by changing the direction of the image, no image blurring occurred even after 30,000 copies.

Similarly, no image blurring occurred even when the wind speeds were kept the same and the directions of ventilation were reversed.

<Effects of the Invention> As described above, the present invention is configured such that the ventilation air speed of the charging section is different between forming and non-forming, thereby suppressing scattering of developer, etc., and reducing the amount of air generated during discharge. It is possible to efficiently remove discharge products such as ozone, which prevents ozone deterioration of the photoreceptor, suppresses image pogging, and stabilizes image quality over a long period of time. .

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams of an embodiment of the present invention. 3 is a photosensitive drum, 3 is a charging section, 3a is a discharge electrode, 3b is a shield member, 3e is a fan, 4 is an exposure section, 5 is a developing section, 8 is a document reading section, 8b is a document, 8C is an illumination lamp, 9 is the control section.

Claims (2)

[Claims] (1) An image forming apparatus using a charging device having a forced ventilation means, characterized in that the air flow velocity by the forced ventilation means is different between when an image is formed and when it is not formed. Device. (2) The image forming apparatus according to claim 1, wherein the air flow velocity is slow when forming an image and fast when not forming an image.