JPH0714993Y2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image forming apparatus such as a copying machine or a printer using electrophotography.

[Prior art and its problems]

Today, image forming apparatuses such as copiers and printers are downsized,
In order to meet the demand for personalization, it is widely known that a photosensitive drum and a developing device, or a photosensitive drum, a developing device and a cleaner are integrated into an image forming unit. In these image forming unit type image forming apparatuses, it is possible to replace the entire unit and simplify the maintenance as well as the useful life of the image forming unit.

However, in consideration of the reduction in size of the apparatus originally intended, the image forming unit including the conventional combination of the photoconductor drum and the developing device or the photoconductor drum, the developing device, and the cleaner is disposed in only one casing. At present, the size is not so much reduced as compared with the case where each process element is provided separately. In particular, the internal space of the photosensitive drum exists only as a space,
No effective use was planned.

[Object of the Invention] In view of the above-mentioned conventional drawbacks, an object of the present invention is to provide an image forming apparatus in which the internal space of the photoconductor drum is effectively used and which is further downsized.

[Key points of device]

According to the present invention, the above-mentioned object is to form a developing portion along the axial direction of the photoconductor drum so as to face the outer circumferential surface with respect to the rotating photoconductor drum that carries a latent image on the outer circumferential surface. In an image forming apparatus configured to develop the latent image by using a supplied developer, a mechanism for accommodating the developer inside the photosensitive drum and transporting the developer to the outside of the photosensitive drum is provided. This is achieved by providing an image forming apparatus characterized by:

[Example of device]

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a schematic configuration diagram of an image forming apparatus using the image forming unit of the present invention. In the figure, the image forming apparatus includes a photosensitive drum 1, a charger 2, a developing belt 3
And a transfer device 4, a cleaner 5 and the like.

A photosensitive layer 1a is formed on the surface of the photosensitive drum 1, and a plurality of fins 1b for agitating the developer are erected inside the photosensitive layer 1a. The fin 1b provided inside the photoconductor drum 1 conveys the toner 6 contained therein by the rotation of the photoconductor drum 1 upward, drops the toner 6 and stirs it to frictionally charge it. The developing belt 3 is an endless belt in which a fine powder having a magnetic force is uniformly contained in a flexible synthetic resin or rubber, and the inner space of the photosensitive drum 1 is formed by a supporting pulley not shown in FIG. It is stretched between the outer circumference and the vicinity of the outer peripheral surface so as to be capable of endless movement.
The charger 2 uniformly charges the photosensitive layer 1a on the surface of the photosensitive drum 1 by corona discharge or the like. On the other hand, the uniformly charged surface of the photosensitive drum 1 is exposed to light 7 corresponding to the recording information to form an electrostatic latent image. The electrostatic latent image formed here is developed by the developing belt 3 in which the developer is adsorbed to a predetermined thickness. The image visualized by the developing belt 3 is transferred by the transfer device 4 onto the sheet 8 conveyed by a timing roller (not shown), and heated and fixed by a fixing device (not shown). On the other hand, the untransferred toner on the surface of the photosensitive drum 1 is removed by the cleaner 5.

FIG. 1 is a perspective view of an image forming unit showing an embodiment of the present invention. In the figure, the other end is omitted because it has a substantially symmetrical structure except for the drive gear. In the figure, the image forming unit includes a photosensitive drum 1 and a developing belt 3.
And the cleaner 5 and the like are integrally unitized. A rotary flange 9 on which a gear 9a is engraved is fixed to the end of the photosensitive drum 1, and the rotary flange 9 is rotatably supported by a fixed flange 10. Therefore, the photosensitive drum 1 is rotated by being driven by a driving mechanism (not shown).

Further, the casing 5a of the fixing flange 10 and the cleaner 5
Are integrally fixed by the upper stay 11 and the lower stay 12. A drive pulley 13 and a support pulley 14 are rotatably supported at an end position of the photosensitive drum 1 between the upper stay 11 and the lower stay 12, and both pulleys and the internal space of the photosensitive drum 1 are supported. An endless developing belt 3 is installed between the outer peripheral surface and the vicinity thereof. A drive gear 13a is provided at the lower end of the drive pulley 13, and the developing belt 3 is driven endlessly in the direction of arrow A by rotationally driving the drive gear 13a by a drive mechanism (not shown). Further, flange portions 13b, 14a are provided upright on the upper and lower ends of the pulleys,
It prevents the developing belt from slipping.

FIG. 3 is a sectional view of an essential part showing the image forming unit. In the figure, the photosensitive drum 1 is fixed to the rotary flange 9 on which the gear 9a is engraved,
It is rotatably supported with respect to 10. On the other hand, the upper stay
A drive pulley rotatably supported between the lower stay 11 and the lower stay 12.
13 is rotationally driven by a drive mechanism (not shown) via a drive gear 13a to move the stretched developing belt 3 endlessly.

FIG. 4 is a side view showing the relationship between the fixed flange 10 and the upper and lower stays 11 and 12. In the figure, the fixed flange 10
In this, there is formed a spike control hole 10a which is a slit for the developing belt 3 to pass through. At the upper and lower ends of the spike control hole 10a, there is a narrow portion having a width substantially the same as the thickness of the developing belt 3 so that the developer adhered to the upper and lower ends of the developing belt 3 (the portion hanging on the pulley) can be scraped off. It is configured. Also,
In the central wide portion, the height of the developing ears adhering to the developing belt 3 is regulated, and the developer on the outside of the developing belt 3 (the surface not facing the photosensitive drum) is scraped off.

FIG. 5 is a perspective view showing the developing belt 3 in a raised state. As shown in the figure, the spikes 15 of the developer are the developing belt 3
Is uniformly formed on the inner surface (surface facing the photoconductor drum 1) of the above, except for a predetermined upper and lower width. The image forming unit configured as described above is attachable to and detachable from the image forming apparatus, and performs the following operation after being attached to the image forming apparatus. The electrostatic latent image formed on the surface of the photoconductor drum 1 by a known technique is formed on the inner surface of the developing belt 3 that is endlessly movable between the inner space of the photoconductor drum 1 and the vicinity of the outer peripheral surface. It is developed by the spikes 15 of the developer thus formed. Therefore, in the image forming unit of the present invention, since the space for executing the developing process is only the thickness of the developing belt 3, the space can be remarkably reduced as compared with the conventional image forming unit.

Further, the toner 6 as a developer is provided in the internal space of the photoconductor drum 1 provided with the fins 1b for agitating, and is sequentially agitated as the photoconductor drum 1 rotates.
It is supplied to the surface of the developing belt 3. Therefore, by utilizing the internal space of the photoconductor drum 1, which has not been effectively used in the past, the unit can be dramatically reduced in size.

In the above embodiments, the case where the one-component magnetic toner is used as the developer has been described, but the present invention is not limited to this, and the same effect can be obtained even when the two-component developer using the toner and the carrier is used. You can

Further, in the above-described embodiment, an example of the image forming unit in which the photosensitive drum 1, the developing belt 3, and the cleaner 5 are integrated into a unit has been described, but the present invention is not limited to this.
Even if the photosensitive drum and the developing belt are integrated into a unit, the internal space of the photosensitive drum can be effectively used, and the unit can be downsized.

[Effect of device]

As described above, according to the image forming apparatus of the present invention,
Toner is stored in the internal space of the photosensitive drum,
Since the developing belt is provided between the inside of the photosensitive drum and the vicinity of the outer peripheral surface, the unit can be downsized and the image forming apparatus can be downsized, and the developing roll is not required unlike the conventional case. Therefore, it is possible to reduce the cost due to the reduction of the number of parts.

[Brief description of drawings]

FIG. 1 is a perspective view of an image forming unit showing an embodiment of the present invention, FIG. 2 is a schematic configuration diagram of an image forming apparatus of the present invention using the image forming unit, and FIG. FIG. 4 is a side view showing the relationship between the fixing flange and the upper and lower stays, and FIG. 5 is a perspective view showing the erected state of the developing belt. Is. 1 ... Photosensitive drum, 1a ... Photosensitive layer, 1b ... Fins, 2
…… Charger, 3 Develop belt, 4 Transfer unit, 5 ……
Cleaner, 6 ... Toner, 7 ... Exposure, 8 ... Paper, 9
...... Rotary flange, 9a …… Gear, 10 …… Fixed flange,
10a ... Brushing control hole, 11 ... Upper stay, 12 ... Lower stay, 13 ... Drive pulley, 13a ... Drive gear, 14 ... Support pulley, 13b, 14a ... Brim part, 15 ... Brush Stand.

Claims (1)

[Scope of utility model registration request] 1. A developing unit is formed along an axial direction of the photosensitive drum, the developing unit being opposed to the outer peripheral face with respect to a rotating photosensitive drum carrying a latent image on the outer peripheral surface, and the developing unit being supplied to the developing unit. An image forming apparatus configured to develop the latent image by using a developing agent, characterized in that a mechanism for storing the developing agent inside the photosensitive drum and transporting the developing agent to the outside of the photosensitive drum is provided. Image forming apparatus.