JPS6150165A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the degradation of a photosensitive body due to ozone or the like generated by corona discharge and the degradation of images near a corona discharger with simple constitution by exhausting a prescribed quantity of air around the corona discharger. CONSTITUTION:Air around corona discharging means 22, 25, and 26 is exhausted through a fan motor 46. This motor 46 is controlled by a control part 56 of a displacement control means, and the displacement is increased while means 22, 25, and 26 do not contribute to image formation, and ozone generated at the discharge time and ozone products are removed. As the result, the degradation of a photosensitive body 21 due to ozone or the like and the degradation of images near corona dischargers are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in an image forming apparatus provided with a corona discharge means at least in the image forming process.

[Technical background of the invention and its problems]

2. Description of the Related Art In recent years, with the increase in information m, a wide variety of image forming apparatuses such as copy ports and electronic printers have been developed and put into practical use.

Further, in an image forming apparatus using the Carlson process, a corona discharge process is used at least in the process of charging a photoreceptor as an image carrier and transferring a developer image (toner image) to a transfer material. It may also be used to assist in separating the transfer material from the photoreceptor and cleaning residual toner from the photoreceptor.

On the other hand, one of the problems when using corona discharge means is that the photoreceptor may deteriorate due to the substances generated by the corona discharge, or they may adhere to the photoreceptor and lower the surface resistance of the photoreceptor, resulting in blurring of the copied image. may occur.

At this time, in the case of a photoreceptor using Se or 5e-Te, this problem is relatively less likely to occur because of positive charging and positive transfer.

This is because the generated substances are mainly ozone and ozone products (for example, NOx), so the generation in positive discharge is smaller than that in negative discharge.

However, this does not mean that it does not occur, and AC may cause peeling.
When corona discharge is used, roughness tends to occur. Further, in the case of a reversal phenomenon, even if a Se-based photoreceptor is used, the transfer results in a negative discharge, so this problem is more likely to occur. Furthermore, when a negatively charged photoreceptor, which is often used in OPC, etc., is used, problems are very likely to occur because both the band width and transfer are negative.

Next, referring to FIG. 3, we will explain about (3) the blur generator (shade) caused by deterioration and adhesion of the photoreceptor due to ozone and ozone products. FIG. 1 in the figure is a drum-shaped photoreceptor as an image carrier, and around this drum-shaped photoreceptor 1 are a charging charger 2, an exposure device 3, a phenomenon device 4, a transfer charger 5, and a peeling charger 6. , a cleaning device 7, and a static elimination lamp 8 are sequentially arranged along the rotation direction.

Note that 9 is a transport path for the paper P formed to pass between the photoreceptor 1 and the transfer charger 5, and 10 is an exhaust fan.

As corona discharge means, there are a charging charger 2, a transfer charger 5, and a peeling charger 6, which perform charging, transferring, and peeling movements. ), occurs.

Excessive ozone causes deterioration of the photoreceptor 1. Furthermore, when the photoreceptor 1 is stationary, ozone products will adhere to the parts A and B on the photoreceptor 1, and especially if the machine is left in a high temperature environment, moisture will adhere to these adhering substances as a nucleus. This causes a partial decrease in surface resistance, resulting in image blurring.

To deal with the latter image blur, it is sufficient to exhaust the air sufficiently when the photoreceptor 1 is stationary, and in a normal machine, the exhaust fan 10 is kept running for a certain period of time even after the copying operation is completed, as shown in FIG.

However, this is insufficient for machines that generate a large amount of ozone, such as those that use OPC photoreceptors, and as machines become smaller and there is less space inside the machine, arterial blur is more likely to occur. Become.

Next, the experimental results on which the present invention is based will be explained with reference to FIG. This shows the relationship between the air flow rate at the charger position, image blur, photoreceptor deterioration, and image quality.

First, in region a, the flow rate is too low, so
I'l ff1f of the ozone atmosphere becomes extremely high, causing deterioration of the photoreceptor 1.

Although the deterioration of the photoreceptor 1 disappears in this region, the density is still too high, and image blurring occurs due to adhesion of ozone products when the photoreceptor 1 is stationary.

The same is true in region C, but in this region, the flow of ozone becomes unstable due to air flow, causing uneven charging, and especially uneven halftones.

Further, in region d, the degree of depth is sufficiently lowered so that blurring is eliminated, but unevenness in halftones becomes more severe.

From the above results, it is quite difficult to eliminate blurring and improve image quality using conventional methods.

Based on the above, the method to avoid the two troubles is as follows: Condition 1) Use an area where there is no problem in image quality and no deterioration of the photoreceptor during copying, and use an area where no blurring occurs after copying.

Condition 2) Uniform air flow prevents unevenness.

is possible.

[Object of the Invention] The present invention was made based on the above-mentioned circumstances, and its purpose is to achieve a simple (1°11 configuration),
An image forming apparatus that prevents deterioration of the photosensitive layer due to ozone and ozone products generated by corona discharge, and prevents image blurring due to the adhesion of ozone and ozone products, and enables good and stable image formation over a long distance. This is what we are trying to provide.

[Summary of the invention]

In order to achieve the above object, the present invention provides an image forming apparatus in which a corona discharge means is provided at least in the image formation process, and in which an exhaust means for exhausting air around the corona discharge means is provided, and the corona discharge means is Picture 13! An exhaust ffi III control means is provided to raise the exhaust gas of the exhaust means during non-operation when it does not contribute to formation, and is configured to prevent ozone and ozone products generated around the corona discharge means from going to the image carrier side. be.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. First, the basic structure of an electronic copying machine as an image forming apparatus will be explained with reference to FIG. In the figure, reference numeral 20 denotes a copying machine main body, and a drum-shaped photoreceptor 21 as an image carrier is provided approximately in the center of the copying machine main body 20. The charger 22, the exposure device 23, the transfer device 24, the transfer charger 25 as a transfer device, the stripping charger 26 as a stripping device, the cleaning device 27, and the static elimination lamp 28 as an afterimage erasing device are sequentially rotated along the rotation direction. It is located.

Also, in the copy number main body 20, a sheet P is automatically taken out from the sheet feed cassette 3° via a sheet feed roller 31 and is ejected through an image transfer section 32 between the photoreceptor 21 and the transfer device 25. A paper conveyance path 34 is formed exclusively in the paper tray 33.

On the upstream side of the image transfer section 32 of the paper conveyance path 34, an aligning roller pair 35 and an m-feeding roller pair 36 are arranged.
Further, on the downstream side, a fixing device 37 and a pair of paper ejection rollers 38 are provided.
is located.

In addition, a manual paper feed D40 for feeding the paper P manually fed from the manual feed assembly table 39 is merged into the transport section located in front of the pair of aligning rollers 35 in the claw transport path 34. It has become.

Also, above dew)! 'The device 23 has a reflector 41 on the back.
It has a configuration including an exposure lamp 42 which is graded 4, a focusing light transmitter (cell pock lens) 43, and a document table 4.
The surface of the original set at No. 4 is scanned, and an image is projected onto the photoreceptor 21 for exposure.

In addition, 45 is a charger 22.2 which is a corona discharge means.
This is an exhaust fan as an exhaust means for generating air flow around the 5.2G, and is driven by a fan motor 46.

Then, by one movement of the exhaust fan 45, the copying body 2
0, there is a state in which an air flow is generated from the right to the left in the figure. The ozone and ozone products are forcibly led out in a predetermined direction, and the ozone and ozone products are removed by an ozone collection filter 47 provided in this air flow path and led out of the main body 2o of the device. It has become.

Note that 55... is a control circuit board, which constitutes a control section that controls the entire plate.

In the above configuration, the photoreceptor 21 is driven in the direction of the arrow in synchronization with the moving operation of the document table 44 by a drive (not shown) (14). After that, the exposure device 23 scans the original held on the original platen 44, and the photoreceptor 21
The latent image is formed by being imaged onto the object.

The latent image on the photoreceptor 21 then faces the developing device 24 as it rotates and is developed. Further, the thus developed developed image is sent to the transfer charger 25 side roughly as the photoreceptor 21 rotates.

On the other hand, the paper P fed automatically or manually at this time is processed by the aligning roller pair 35 so that the leading edge (skew) etc.
3. He is in a state where he is once a samurai in a corrected state. Then, this paper P is fed into a state where it is exposed to the developer image on the photoreceptor 21 in synchronization with the image forming operation, and the developer image is transferred to the paper frJ1P by the movement of the transfer charger 25.

Next, this paper P is electrostatically peeled off from the photoreceptor 21 by the peeling charger 26, conveyed through the paper conveyance path 34, and fed between the heating roller 50 and pressure roller 51 of the fixing device 37, where it is , the developer image is fused and fixed onto the paper P.

Thereafter, the paper P is ejected to the paper ejection tray 33 via the paper ejection roller pair 38.

Note that the surface of the photoreceptor 21 after the transfer using the current agent is 1+'1
After the residual agent (toner) is removed by the blade 52 by facing the lHfQ27, the static elimination lamp 2
8, the afterimage is erased and the image becomes clean, ready for the next copying operation.

On the other hand, as mentioned above, the charging charger 22, the transfer charger 25,! H! With the corona discharge of the a-charger 26, ozone and ozone products are generated around it. As explained with reference to FIG. 4, these cannot be completely removed from around the photoreceptor 21 simply by continuing to operate the exhaust fan 45 even after the copying operation is completed.

Therefore, in the present invention, as shown in FIG. 2, the voltage of the motor 46 is increased by an exhaust control signal from the control section 56 from the end of the copying operation that affects the image until the photoreceptor stops or immediately thereafter. The rotation of the exhaust fan 45 is increased. Then, by increasing the exhaust volume from the first level to the second level, the air flow m at the charger position is changed to the area shown in FIG. In other words, the above-mentioned trouble will not occur, and condition 1) will be satisfied.

Through these implementations, it was confirmed that even in a process using a photoreceptor with a drum diameter of 50 mm, it was possible to achieve a practical level of copying iooo copies.

In the above-mentioned embodiment, an explanation was given of an application applied to the number of electronic copies, but the invention is not limited to this, and may also be applied to an electrophotographic printer, for example, and in short, a device provided with a corona discharge means at least on image formation. Of course, that's a good thing.

In addition, it goes without saying that the present invention can be modified in various ways without departing from the gist of the invention.

(Effects of the Invention) As explained above, the present invention provides an image forming apparatus in which a corona discharge means is provided at least on an image forming process.
An exhaust means for exhausting the air around the corona discharge means is provided, and an exhaust amount control means is provided to raise the exhaust gas of the exhaust means to 0 when the corona discharge means does not contribute to image formation. The structure is such that ozone and ozone products do not go to the image carrier side. Therefore, although the structure is simple, the deterioration of the photoreceptor due to ozone and ozone products generated by corona discharge and its adhesion can be prevented.
The Iζ effect will be realized if an art forming apparatus can be provided which prevents the blurring caused by the art and allows good and stable image formation over a long period of time.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention,
Fig. 1 is a schematic longitudinal sectional front view of an electronic copying device as an image forming device, Fig. 2 is a timing chart showing the operation of the main parts, and Fig. 3 is an image caused by deterioration and adhesion of the photoreceptor due to ozone and ozone products. Fig. 4 is an explanatory diagram for explaining the structure of generating blur, Fig. 4 is a timing chart showing the operation of the main parts of the conventional example, and Fig. 5 is an explanatory diagram for explaining the experimental results on which the present invention is based. be. 21... Image carrier (photoreceptor), 22.25° 26... Corona discharge means (charger), 4
5... Exhaust means (exhaust fan), 46...
...Fan motor, 56...Control section (exhaust ff
i II + control means).

Claims (5)

[Claims] (1) In an image forming apparatus provided with a corona discharge means at least in the image forming process, an exhaust means for exhausting air around the corona discharge means, and an exhaust means for exhausting air around the corona discharge means when the corona discharge means does not contribute to image formation. An image forming apparatus comprising: a displacement control means for increasing the displacement of the means. (2) The exhaust amount control means is configured to control the exhaust amount so that ozone and ozone products generated around the corona discharge means do not go to the image carrier side. The image forming apparatus described above. (3) The image forming apparatus according to claim 2, wherein the image carrier is a photoreceptor. (4) The image forming apparatus according to claim 1, wherein the exhaust means comprises an exhaust fan. (5) The image forming apparatus according to claim 4, wherein the means for increasing the displacement of the exhaust means is configured to increase the voltage of a fan motor that drives an exhaust fan.