JPH0310518Y2 - - Google Patents

Description

[Detailed description of the invention] (Technical field) The present invention relates to an image forming apparatus, and more specifically,
The present invention relates to an image forming apparatus that can be applied to an electrophotographic copying machine equipped with a dry developing device.

(Prior Art) Conventionally, an image device configured by mounting various members inside a casing is known.

FIG. 1 shows a cross section of a main part of an electrophotographic copying machine having a dry developing means, which is an example of such an electrophotographic copying machine.

In the figure, reference numeral 1 indicates a casing, and inside the casing 1 various members of an electrophotographic copying machine are assembled. Reference numeral 2 indicates a photosensitive drum, which is rotated in the direction of the arrow during copying. As is well known, the photosensitive drum 2 is surrounded by a charger 3, an eraser 4, a developing device 5, a paper feed guide 6, a transfer charger 7, a separation charger 8, and an antistatic charger 9. , a cleaning brush 10, a cleaning blade 11, a static elimination lamp 12, and the like are arranged.

Among these members, a light transmitting member 13 made of transparent glass for dustproofing is supported by support members 14a and 14b in a space above the circumferential surface of the photoreceptor drum and at an intermediate position between the charger 3 and the developing device 5. It has been fitted.

In such an apparatus, during copying, as is well known, while the photoreceptor drum 2 is rotating, a charger 3 uniformly applies an electric charge to the photoreceptor from which the electric charge has been previously removed by the static eliminating brush 12. It will be done. Then, a part of this charge is removed by an eraser 4 from an unnecessary portion. Next, exposure light from a document (not shown) is sequentially imaged onto the photoreceptor drum 2 via the mirror _M1 and the light transmitting member 13, and exposed.

In this way, the photosensitive drum 2 carrying the electrostatic latent image is transferred to the developing sleeve 5 while passing through the developing device 5.
It is developed with dry toner in contact with the magnetic brush on a. Then, the toner image on the photosensitive drum is transferred to a transfer paper fed out from a paper feed guide 6 at the appropriate timing by the action of a transfer charger 7. The transfer paper to which the toner image has been transferred is transferred to a separate charger 8.
While being separated from the photoreceptor drum 2 by the action of , it is sent in the direction of arrow A and subjected to a fixing operation. On the other hand, after the toner image has been transferred to the transfer paper, the photoreceptor drum 2 continues to rotate, and after being neutralized by the charger 9, the remaining toner is removed by the cleaning brush 10 and the cleaning blade 11, which completes the copying process. End the cycle.

In devices that form images in this manner, wind is often blown around the photosensitive drum 2 for purposes such as cooling.

Furthermore, in order to prevent the charge wire 3a of the charger 3 from deteriorating, it is often done to blow air toward the photosensitive drum 2 through the slit 3b at the back of the charger 3.

The means for generating these winds is the casing 1
This is carried out by a fan 15 located inside the camera and at an appropriate position on the left side in the figure.

For this reason, wind flows often occur around the photoreceptor drum 2, and this wind flow causes the apparatus to become unstable.

To explain with reference to FIG. 1, the developing sleeve 5a
At the portion facing the photoreceptor drum 2, the magnetic brush formed on the circumferential surface of the developing sleeve 5a is in contact with the circumferential surface of the photoreceptor drum, so the flow of air in this portion is blocked. Therefore, the flow of air sent out by the fan 15 is directed obliquely to the upper right along the upper casing 5b of the developing device 5, as shown by arrow B, and is discharged to the atmosphere from an exhaust port (not shown).

However, at that time, this wind flow is caused by the developing device 5.
It functions to blow out fine toner powder generated by the rotation of the paddle wheel 5d, etc., from the gap between the bristle brushes 5c. Then, this toner fine powder rides on the flow of the wind and adheres to the surface of the light transmitting member 13 near the air passage, preventing the exposure light from passing through and causing background stains on the copied image as the light intensity decreases. cause

Alternatively, it may adhere to the eraser 4 and stain it.

(Objective) Therefore, the object of the present invention is to provide an image forming apparatus which is equipped with means for suppressing the blowing out of fine toner powder from the developing device 5 due to the above-mentioned wind flow and for preventing toner staining on required members. .

(Structure) The structure of the present invention will be described below based on one embodiment.

In the conventional technology, the air passage is constituted by the space between the developing device 5 and the light transmitting member 13. Focusing on the fact that when the wind passes through this space, the fine powder inside the developing device is blown out, this example was developed. Now, as shown in FIG. 2, the supporting members 14a, 14 of the light transmitting member 13 are
A connecting member 16 was interposed between the developing device 5 and the developing device 5 to connect the gap between the two in a hermetically sealed manner. Furthermore, the connecting member 16 is cylindrical and is configured to surround the surface of the light transmitting member 13 facing the photosensitive drum.

Here, as a means for bringing the connecting member 16 and the casing 5b of the developing device 5 into close contact, for example, a suitable sealing material 17 is interposed.

With this configuration, since the conventional path of air directed in the direction of arrow B is cut off, the blowing out of toner particles from the developing device will no longer occur.

Note that the air flow from the charger 3 flows in the axial direction of the photoreceptor drum 2, that is, in the illustrated example, in the direction penetrating the page, and then passes through the gap with the side plate of the casing before exiting the discharge port. It will come out. This wind flow is shown by arrow C in FIG.

In this example, a case has been described in which wind is actively sent to the charger 3, but even when such wind is not sent, wind is generated around the photoreceptor drum 2 as it rotates. Since the flow of air is generated, an airflow substantially directed in the direction of arrow B is generated, so that this example has the effect of preventing toner staining. Furthermore, since the passage of air in the direction of arrow B is blocked, the eraser 4 located along the way is no longer contaminated.

(Effects) According to the present invention, since the passage through which the air flows is located away from the location where the developing device and the member where it is desired to prevent toner contamination are disposed, fine toner powder is not blown out from the developing device, and therefore, the toner is not blown onto the specified member. It is advantageous to avoid stains.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of an electrophotographic copying machine illustrating a prior art, and FIG. 2 is a schematic sectional view of a main part of an electrophotographic copying machine illustrating an embodiment of the present invention. 2...Photosensitive drum, 5...Developing device, 13...
...Light transmitting member, 14a, 14b...Supporting member, 1
6...Connection member.

Claims (1)

[Claims for Utility Model Registration] An image forming device incorporated in a casing, comprising a charger disposed close to a photoreceptor drum;
It has a developing device that uses dry toner, and a dust-proof light transmitting member that is placed in the space above the circumferential surface of the photosensitive drum at an intermediate position between the charging device and the developing device. In an image forming apparatus that generates an airflow toward
An image forming apparatus characterized in that the image forming apparatus is connected in a sealed manner by a connecting member, and a part of the connecting member is formed so as to surround a surface of the light transmitting member facing the photoreceptor drum.