JPS62283357A - Image forming device - Google Patents

Abstract

PURPOSE:To surely prevent deterioration of an image carrier by discharging corona products such as ozone etc., remaining in a discharger to outside of the body of the device from a discharge port provided in the discharger through a exhaust fan. CONSTITUTION:A primary charging device 4 consists of a discharge line 4a placed above a photosensitive body 3 nearly parallel to it, and shielding plates 4b, 4b arranged its right and left sides opposite to each other, and upper opening between the two shielding plates 4b, 4b is covered with the upper face plate 2a of a process cartridge 2. A discharge port 17 for reading corona products such as ozone etc., remaining in the charging device 4 to an exhaust fan 16 and a shutter 18 for opening and closing the discharge port 17 is provided in the upper face plate 2a.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention A. Purpose of the Invention [Industrial Field of Application] The present invention is applicable to photocopying machines, laser beam printers, etc. The present invention relates to image forming apparatuses such as the above.

[Conventional technology]

In this type of image forming apparatus, a corona discharger is used, for example, to charge or remove electricity from an electrostatic latent image carrier. This corona discharger is widely used because it has a simple structure, can uniformly charge or remove static electricity, and is durable.

[Problem that the invention seeks to solve]

However, corona products such as ozone are generated during discharge and adhere to the electrostatic latent image carrier, lowering the surface resistance of the image carrier and causing so-called image running and blurring phenomena.

In order to prevent the above phenomenon, it is common practice to provide an exhaust fan inside each image forming bag to remove the corona products. In this case, in many image forming apparatuses, the exhaust fan also serves as a heat exhaust fan, and the air volume must be considerably increased.Also, the exhaust fan continues to rotate even during the standby time of the apparatus, causing noise problems.

Therefore, after the image forming operation line Y, the exhaust fan is stopped (y), and only the heat exhaust fan installed separately from that exhaust fan is rotated.
There is also a device, but in such a device, the corona radiation completely removes the products on the roller inside the container, and the image carrier part facing the discharger after the attached body 1) is exposed to ozone. C
There is a problem in that surface deterioration occurs and a flow phenomenon occurs in that area.

The object of the present invention is to ensure that corona products generated from a corona discharger are discharged from the image generator to the outside of the human body, and to reduce noise during standby time.

Structure of the Invention [Means for Solving the Problems] What has not yet been invented is an exhaust fan for discharging the air inside the main body of the apparatus to the outside of the main body, and a corona discharger for charging or removing electricity on the image carrier, etc. In an image forming apparatus equipped with an electric appliance, the corona products generated by the corona discharger are discharged outside the apparatus body by the exhaust fan from a discharge port provided on the opposite side of the discharger to the image carrier. When the exhaust fan is driven for a certain period of time during and after image formation, an opening/closing shutter is provided for the exhaust [1], and the shutter is closed during image formation, and the exhaust fan is driven for a certain period of time during and after image formation. It is characterized by being opened when the fan is running.

[For production]

During image formation, the discharge port of the discharger is closed by a shutter, and corona discharge is discharged or discharged.

After the image forming process is completed, the shutter opens and corona products such as ozone that remain in the discharger are discharged from the discharge port of the discharger to the outside of the image forming apparatus body through the exhaust fan.

After a certain period of time has elapsed after the end of the image forming process, the exhaust fan is stopped and the noise during the standby time is reduced.

〔Example〕

The first point is 5 (in Figure 0, which shows an example in which the invention is applied to a laser beam printer as an image forming apparatus, 1 is a device).
! A main body 1 and a process cartridge 2 are detachably attached to the main body 1, and a photosensitive drum 3 as an image carrier, a charger 4, a developing device 5, and a cleaning device 6 are housed in the cartridge 2. There is. A pre-exposure light source 7 exposes the photosensitive drum 3 through an opening 8 formed in the h-face plate 2a of the cartridge 2.

9 is laser unit 1. A scanner unit having a built-in polygon mirror lens system irradiates the photosensitive tram 3 with a laser beam 9a modulated by an image signal via a reflecting mirror 10.

- Next, a photosensitive drum 3 which is uniformly charged by the 7+2 column 4 forms a two-static latent image. The electrostatic latent image is
The toner is developed by the developer 5 and becomes IR visible, and the cassette 1
Transfer material 13 is fed from 1 to 12 by feeding roller 12'V.
Seventh, after being electrostatically transferred by the transfer charger 14, the fixing device 15
It is thermally determined at n. Reference numeral 16 denotes an exhaust fan for ventilation inside the apparatus main body 1 provided on the side of the fixing device 15, which cools the scanner unit 9, and is a suction fan for removing ozone, which will be described later. It also serves as a heat exhaust fan to remove heat from the main unit.

The illustrated example is one in which the uninvented invention is applied to the discharger (charger) 4 that applies primary charging to the photosensitive drum 3,
In this embodiment, OPC (organic photoconductor) is used as the photosensitive drum 3, and a negative corona discharger is used as the negative charger 4.

I- The primary charger 4 includes a discharge wire 4a arranged above the photosensitive drum 3 and substantially parallel to it, as shown in FIGS. 1 and 2.
and shield plates 4b arranged facing each other on the left and right sides thereof.
4b, and the upper opening between the two shield plates 4b is covered with the upper plate 2a of the process cartridge 2.

And on the L face plate 2a, obi 1! The exhaust fan 16 is provided with an exhaust port 17 for guiding corona products such as ozone remaining in the pump 4 to an exhaust fan 16, and a shutter 18 for opening and closing the exhaust port 17. 18a is an opening/closing shaft of the shutter 18.

As shown in FIG. 3, the shoe opening/closing shutter 18 is always biased by a spring 19 to rotate in the direction of closing the discharge port 17, and when the process cartridge 2 is removed from the apparatus main body, the discharge port 17 is closed and external light is blocked. 20 is a cam for opening and closing the shutter 18, and 21 is a motor for driving the cam, which does not enter the photosensitive drum.

The shutter 18 and exhaust fan 16 are controlled according to one image forming operation, and FIG. 4 is a timing chart showing an example thereof.

The print start signal drives the main motor (not shown in the diagram).
ttH, rotate the photosensitive drum 3. At the same time, the exhaust fan 16 is driven and the pre-exposure light source 7 is turned on.

After a waiting time until the rotation of the main motor stabilizes and the circumferential speed of the photosensitive drum 3 becomes constant, discharge of the negative blower 4 is started (t2), and a predetermined image forming operation is executed. At this time, the shutter 18 is closed to prevent light from the pre-exposure light source 7 from entering the primary charger 4.

When the image forming operation is completed, the power supply to the charger 4 is cut off (70), and the main motor is driven until all the primary charged parts on the photosensitive drum pass through the pre-exposure section and then stopped. At the same time, the pre-exposure light source 7 is turned off. The shutter 18 is opened with a slight delay (t4) after the primary charging is completed (t3). This is to prevent primary charging while the shutter 18 is open.

Next, after a certain period of time has elapsed since the main motor stopped, the exhaust fan 16 stops (t8), and at the same time the shutter 18 is closed. However, the shutter 18 may be left open except for the image forming operation, and the above fixed time is preferably about 5 seconds to 2 minutes, which is enough to remove ozone around the photosensitive drum, and at the same time make noise from the exhaust fan 16. I don't really care either.

Note that the present invention is not limited to the first-base belt, but can also be applied to the transfer charger 14 and other corona dischargers.

C. Effects of the Invention Since the present invention has the above-described configuration, corona products such as ozone that remain in the discharger can be discharged from the discharge port provided in the discharger to the outside of the apparatus main body through the exhaust fan. Therefore, deterioration of the image carrier due to corona products can be reliably prevented.

Further, since the above-mentioned discharge port is closed with a shutter during the formation of one image so as not to impede the discharge effect, the opening area of the discharge port can be made sufficiently large, so that the exhaust fan can be made smaller and lighter.

Furthermore, since the exhaust fan is stopped after a certain period of time has passed after the end of the image forming process, it is possible to reduce noise during the standby time.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a longitudinal sectional view of the image forming apparatus of the present invention, FIG. 2 is an enlarged sectional view of the vicinity of the primary charger, FIG. 3 is a perspective view of the upper part thereof, and FIG. FIG. 3 is a control timing chart diagram of the invention device. 1 is the main body of the apparatus, 2 is the process cartridge, 3 is the image carrier (photosensitive drum), and 4 is the corona discharger (-Naruta')
, 16 is an exhaust fan, 17 is an exhaust port, and 18 is a shutter.

Claims (1)

[Claims] (1) In an image forming apparatus equipped with an exhaust fan for discharging air inside the apparatus body to the outside of the apparatus body and a corona discharger for charging or eliminating static electricity on an image carrier, etc., the corona generated by the corona discharger is The product is configured to be discharged from the apparatus main body by the exhaust fan through a discharge port provided on the opposite side of the discharger from the image carrier, and the exhaust fan is driven for a certain period of time during and after image formation. At the same time, an opening/closing shutter is provided at the discharge port,
An image forming apparatus characterized in that the shutter is closed during image formation, and is opened at least during other times when an exhaust fan is driven.