JPH03237471A - Image forming device and process cartridge attachable/ detachable to/from the image forming device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a defective image due to ozone by arranging a barrier between an electric charger and the succeeding image forming process means part arranged on the downstream side of the charger in an image carrier moving direction. CONSTITUTION:The plate-like barrier 25 is unitedly fixed to the edge part of an aperture on the primary charger (2) side of an image exposing window 8 to be an image exposing aperture formed on the upper plate 10a of a process cartridge 10 so as to be directed to a photosensitive body 1 and respective gaps (a), (b) are formed between the barrier 25 and the body 1 and between the barrier 25 and the charger 2. Since the barrier 25 is arranged between the charger 2 and the succeeding image forming process part arranged on the downs-stream side of the charger 2 in the image carrier moving direction, the air pressure of the process part can be increased higher than air pressure in the charger 2 on the periphery of the image carrier. Thereby, the outflow of ozone or the like from the charger 2 to the process part can be prevented and air flows from the process part into the charger 2 through the gap between the charger 2 and the image carrier 1, so that the stay of ozone or the like in the vicinity of the periphery of the image carrier 1 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention f relates to an image forming apparatus. More specifically, image forming process means including a charger are sequentially disposed in the direction of surface movement of an image bearing member such as a photoreceptor or dielectric which is driven by surface movement, and air is allowed to flow through the charger. The present invention relates to an image forming apparatus.

[Conventional technology]

A corona charger is generally used as a charger for use in the image forming apparatus as described above. However, corona chargers generate ozone, and when the concentration of ozone is high, ozone products (NOx) adhere to the surface of the image carrier, and the charge on the image carrier is diffused, resulting in image blurring called image blur. Cause. In order to prevent this, conventional methods used to pump air into the charger.
ft to prevent ozone and the like from accumulating in the charger.

Figure 1g9 is a cross-sectional view of the main parts of a conventional image type fs device. Developing device 4, transfer charger 16, cleaning device 5, pre-exposure device 6
An imaging process means such as, for example, is disposed and a known imaging process is carried out.

The charger 2 includes a discharge wire 2a, and a first shield plate 2b and a second shield plate 2C, which are arranged facing each other on both the left and right sides of the discharge wire 2a. loa is the light shielding plate of the main body of the device or the top plate of the cartridge incorporating the above process equipment, and 7 is the above plate 1.
A pre-exposure window is formed at 0a, and 8 is an image exposure window.

Then, the air outside the plate 10a is sucked into the plate 10 from the image exposure window 8 by the air suction force of the fan 20 as shown in FIG. 9.
a, and most of the air ft is between the plate 10a and the second
It enters the charger 2 through the gap S1 between the shield plate 2C and the upper edge, flows out of the charger 2 through the gap S2 between the first shield plate 2b and the photoreceptor 1, and then passes through the pre-exposure window 7 to the plate 10a. Exit to the outside of. Due to this air circulation, the band M stays inside the charger, but the actual air circulation inside the charger 2 flows through the upper part of the charger 2 and along the inner surface of the first shield plate 2b, and flows through the gap S2. This causes the flow path passing through the air to become uneven, and air stagnation occurs near the inner surface of the second shield plate 2C. Therefore, an air region with high ozone concentration is created in that area.

On the other hand, a part of the air f2 that has entered the inside of the plate 10a that covers the image exposure window 8 flows from the outside of the second shield plate 2C along the circumferential surface of the photoreceptor and forms an image between the charger 2 and the developer 4. A vortex is generated in the exposure section 3. This flow f2 does not significantly increase the air pressure on the circumferential surface of the photoreceptor in the image exposure section 3, but rather the air pressure inside the charger 2 is higher due to the pressure of the corona wind. Therefore, air with a high ozone concentration flows out from the gap S3 between the second shield plate 2C and the photoreceptor t to the image exposure section 3 on the downstream side of the charger 2 in the rotational direction of the photoreceptor fl.
There is a problem in that the charge on the photoreceptor is diffused and causes image blurring.

The invention of the invention is to remove the image carrier (photoreceptor) from within the charger.
The purpose of this invention is to prevent the ozone and the like from flowing out to the image forming process section on the downstream side in the direction of surface movement, and to smooth the flow of air into the charger to reduce image defects.

The invention and its structure [Means for solving the problem] The invention consists of sequentially arranging image forming process means including a charger in the direction of plane movement of an image bearing member driven by plane movement. In an image forming apparatus in which air is allowed to flow through the charger, the charger is placed in an open position between the charger and a next image forming process means downstream of the charger in the direction of movement of the image carrier surface. The feature is that a barrier is provided to restrict the flow path of air to the air.

[For production]

By providing a barrier between the charger and the next image forming process section on the downstream side in the direction of movement of the image carrier surface,
It is possible to make the air pressure in the next image forming process section higher than the air pressure in the charger on the circumferential surface of the image carrier. Therefore, ozone etc. are prevented from flowing out from inside the charger to the next process section, and air flows into the charger from the above-mentioned next process section through the gap between the charger and the image carrier. This prevents ozone and the like from remaining near the circumferential surface of the image carrier in the charger.

In FIG. 0, which is a vertical cross-sectional view of a laser beam printer, reference numeral 10 denotes a process cartridge detachably attached to the main body A of the apparatus. A developing device 4 and a cleaning device 5 are housed.

In the figure, reference numeral 11 denotes a scanner unit that includes a laser unit, a polygon mirror, and a correction lens system, and a laser beam 11a modulated by 9 image signals is transmitted from the image exposure window 8 of the cartridge top plate 10a through the image exposure window 8 of the cartridge top plate 10a to the photoreceptor 1. irradiate. A known organic photoreceptor is formed on the photoreceptor 1, and uniform charging is performed by the charger 2.
An electrostatic latent image is formed by dissipating the charge in the area irradiated with the laser beam. The electrostatic latent image is developed with charged particles (hereinafter referred to as toner) T in the developing device 4, and the transfer material 15 is fed from the paper feed cassette 13 by the feed roller 14AJ.
The transfer material 15 transferred by the transfer charger 16 is then thermally fixed by the fixing device 17, and then discharged onto the tray 19 via the paper discharge roller 18. - The toner remaining on the force photoconductor 1 is removed by the cleaning device M5,
The charging history of the photoreceptor 1 is erased by the pre-exposure device 6, and the same process is repeated again.

Fig. 2 shows a plan view of the interior of the apparatus schematically showing the airflow inside the apparatus main body by the exhaust fan 20. Fi! , and the air suction force of the exhaust fan causes air to flow as shown by the arrow in the figure. Reference numeral 21 denotes a photoreceptor drive motor, and a plate-shaped barrier 25 is integrally provided at the edge of the opening on the two-component charger 2 side toward the photoreceptor 1. Gaps a-b are formed between the barrier 25, the photoreceptor 1, and the charger 2, respectively.

The image exposure window 8 is opened by the air suction force of the exhaust fan 20.
Air entering the cartridge 10 from the cartridge 10 flows along the barrier 25 and hits the photoreceptor l. Therefore, the air pressure on the circumferential surface of the photoreceptor increases. A part of the air that hits the photoreceptor 1 flows toward the developing device 4 on the circumferential surface of the photoreceptor, but most of the molecules 1 flow through the barrier 25 from the gap a between the lower end of the barrier 25 and the circumferential surface of the photoreceptor. and the second shield plate 2C, and the gap S between the upper end of the shield plate 2c and the cartridge top plate 10a.
1 and flows into the i-electric appliance 2. At this time, on the circumferential surface of the photoreceptor 1, the air pressure on the image exposure □3 side is higher than in the charger 2.

Contrary to the conventional case described in FIG. 9, air flows f3 into the charger 2 from the image exposure section 3 side through the gap S3 between the second shield plate 2c and the photoreceptor 1.

Therefore, the dense ozone in the charger z does not flow to the image exposure section 3, and moreover, the second shield plate 2c in the charger z,
! = New air flows into the corner of the surface around the photoreceptor, so
Ozone retention is prevented and ozone concentration is reduced.

Note that if the gap a-b between the barrier 25, the photoreceptor 1, and the charger 2 is too small, the amount of air to the charger 2 will be reduced, and if it is too large, the gap around the photoreceptor under the second shield plate 2C will be reduced. Since the pressure on the image exposure section 3 side on the surface is low, the design should be made appropriately.In this embodiment, a is 10 m+*,
There were 4 questions for b.

Furthermore, the above-mentioned gap a-b does not necessarily need to be constant in the axial direction of the photoreceptor, but may be changed as appropriate depending on the state of air flow within the device in order to equalize the amount of air flowing into the charger. Good too.

4 and 5 show examples in which the gap a between the barrier 25 and the photoreceptor 1 is changed in the axial direction of the photoreceptor 6 For example, an exhaust fan 20
When the photoreceptor 1 is disposed at one end in the axial direction as shown in FIG. 2, more air flows toward the side closer to the exhaust fan 20. Therefore, in FIG. 4, the lower end surface 25a of the barrier 25 is formed into an inclined surface to create a gap at the side closer to the exhaust fan 20 (on the right side in the figure).
is made to gradually become smaller than the gap a2 on the opposite side, and the air it flowing through the band W container 2 is approximately equal over its entire length in the longitudinal direction. FIG. 5 shows that when exhaust fans are provided on both sides in the axial direction of the photoreceptor, the lower end surface of the barrier is arranged at the lower end 25a of the concave wall 25 so that the gap a3 at both ends near the exhaust fan is smaller than the gap va4 in the center. are brought close to the photoreceptor l, and the upper end 25b of the barrier 25, ! : A gap C for air inflow is formed between the opening edge of the image exposure window 8.

@The air that entered from the exposure 18 flows into the flow fl that is sucked into the charging 'B2 from the gap C through the gap S1 between the shield plate 2C of the charger 2 and the cartridge top plate 10a, and the flow fl between the shield plate 2c and the barrier 25. The flow is divided into a flow f2 toward the photoreceptor 1 through the space between the two and the two. The pressure of the air toward the photoreceptor 1 is higher than the pressure inside the charger 2 because it is surrounded by the shield plate 2C and the barrier 25, and as in the example in FIG. flows f3 into the charger 2 from the gap S3 between the shield plate 2C and the photoreceptor l.

7 and 8 show an example in which a plurality of rectifier plates 26 are provided on the side of the barrier 25 facing the charger 2 in the examples of FIGS. 3 and 6, respectively.

For example, as shown in FIG. 2, if the exhaust fan 20 is arranged to one side due to the space inside the main body A of the apparatus, the air flowing between the VX wall 25 and the charger 2 will flow in the horizontal direction, i.e. It tends to flow obliquely in the axial direction of the photoreceptor.

As a result, the efficiency of air intake and exhaust to the charger 2 deteriorates, and the ozone concentration in the charger on the side opposite to the location where the exhaust fan 20 is disposed increases. Therefore, in order to prevent the above-mentioned lateral flow, a rectifying plate 26 is provided as shown in FIGS. 5 and 6, and the above-mentioned lateral flow is prevented by the rectifying action of the rectifying plate 26.

Note that the water n formed by integrating the rectifying plate 26 with the barrier 25 forms the barrier 2 between the 1Trt device 2 and the next image forming process section downstream of it in the direction of movement of the image carrier surface.
The charger 2 can be connected to the charger 2 by simply installing the
It is possible to prevent ozone from flowing out to the next process section, and the air flowing into the charger 2 from the next process section with the charger through the gap with the image carrier l causes the inside of the charger 2 to be reduced. It is possible to efficiently reduce the ozone concentration in the image, and has the effect of reliably preventing the occurrence of image defects due to ozone.

[Brief explanation of drawings]

Figure 1 is a longitudinal cross-sectional view of an image forming apparatus to which a wooden gate is applied, Figure 2 is a plan view of the interior of the apparatus schematically showing the air flow inside the apparatus body by an exhaust fan, and Figure 3 is a wooden one. A cross-sectional view of main parts showing one embodiment, 1st is a developing device, 25 is a barrier, and 26 is a rectifying plate.

Claims (2)

[Claims] (1) It has a movable photoreceptor, a charger that charges the photoreceptor, and an exposure means that image-wise exposes the photoreceptor charged by the charger, and air is circulated through the charger. The image forming apparatus is characterized in that a barrier is provided at a position between the charger and the image exposure section of the photoreceptor to form an air flow path between the charger and the charger. Forming device. (2) A process that includes a movable photoreceptor, a charger for charging the photoreceptor, and an opening for imagewise exposure of the photoreceptor charged by the charger, and is detachable from the image forming apparatus. The process cartridge is configured to allow air to flow through the charger when the process cartridge is installed in the image forming apparatus, and the process cartridge is provided at a position between the charger and the opening. A process cartridge characterized in that a barrier is provided to form an air flow path between the cartridge and the charger when the cartridge is installed in the image forming apparatus.