JPH0627795A - Developing apparatus - Google Patents

Abstract

PURPOSE:To prevent the leakage of a developer from a developing apparatus provided in an image forming device. CONSTITUTION:An air exhaust port 30 is provided at a position facing to the developing sleeve 26 upper periphery of a top cover 21 which is to be fit on the upper face of a developing apparatus body 20 forming the housing of a developing apparatus 6, and further a filter member 31 is provided so as to close the air exhaust port 30. A splashing developer in the developing apparatus 6 is picked up by the filter member 31 via air exhaust port 30 where air flows. A bottle neck 32 is formed between the periphery of a photoreceptor drum 3 and the top face of a developer leakage preventive wall 21a facing to the periphery so as to prevent the leakage of the developer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer leakage preventing means of a developing device installed in an image forming apparatus such as a copying machine or a printer.

[0002]

2. Description of the Related Art Generally, an electrophotographic image forming apparatus such as a copying machine or a printer includes a platen on which a document is placed, a document irradiation lamp reciprocating below the platen, a reflection mirror, and a fixed projection lens and a reflection mirror. A configured scanning optics,
A photosensitive drum that is charged with a predetermined potential by a band electrode and rotates, a developing device that applies toner to an electrostatic latent image formed on the surface of the photosensitive drum by the scanning optical system to develop the electrostatic latent image, and the photosensitive drum. A transfer pole that transfers a toner image onto a recording sheet surface that is a transfer material that is conveyed toward the lower side of the body drum surface, a separation pole and a removing electrode, and fixes the toner image transferred onto the recording sheet surface. The fixing device is composed of a fixing device and a cleaning device for removing toner, paper dust and the like remaining on the surface of the photoconductor after transfer.

Then, desired toner images are successively recorded on the surface of the recording paper which is intermittently conveyed along a predetermined conveying path.

FIG. 4 shows a cross section of the main part of the developing device 6.
Is a main body of the developing device that forms the housing of the developing device 6, 22 is a first stirring member, 23 is a second stirring member, 24 is a supply roller, 26 is a developing sleeve, and 28 is developing applied to the peripheral surface of the developing sleeve 26. A cylindrical rod which is a developer thin film forming means having rigidity for regulating the amount of the developer, 28a is a spring plate for regulating the amount of the developer conveyed, and the cylindrical rod 28 has no developer on the developing sleeve 26. It is pressed with a constant load in the state. 27 is a scraper that cuts off the ears of the developer, 25 is a stirring partition plate,
Reference numeral 21 is an upper lid integrally attached to the upper surface of the developing device main body.

The toner replenished in the developing device 6 is sufficiently agitated and mixed with the carrier by the second stirring member 23 rotating in the direction of the arrow and the first stirring member 22 rotating so as to overlap each other in the opposite direction. The upper developer D is sent to the developing sleeve 26 via the supply roller 24.

The first stirring member 22 and the second stirring member 23 are screw-shaped members having a spiral angle of left-handed rotation in the opposite arrow directions, and are conveyed to the inner side by the thrust of the first stirring member 22. The toner and the carrier successively pass over the stirring partition plate 25 whose upper edge is slanted downward in the direction toward the back of the drawing, and the second
It moves to the side of the stirring member 23 and is conveyed to the front side of the drawing by its thrust, and becomes a homogeneous developer D that is triboelectrically charged by the mixing action of the toner and the carrier during that time, and is a sponge-like supply roller that rotates in the arrow direction The toner is adhered in a layered manner on the peripheral surface of the developing sleeve 26 which rotates clockwise by the arrow 24.

Then, the toner conveyed by the developing sleeve 26 is applied to the electrostatic latent image formed on the peripheral surface of the adjacent photosensitive drum 3 with a predetermined gap from the surface of the developing sleeve 26 to form a toner image. Is developed. The rotations of the first and second stirring members 22, 23, the supply roller 24, and the developing sleeve 26 are transmitted to each other by a drive transmission mechanism mounted on the side surface of the developing device main body 20.

The toner scattered in the image forming apparatus is sucked by a suction provided at a proper position.

[0009]

However, as shown in FIG. 4, when the spikes of the developer are cut by the scraper 27 located diagonally above and right of the developing sleeve 26, the cut developer gradually collects and the developing sleeve is collected. A developer pool D ₁ as shown in the drawing is formed in a relatively narrow space between 26, the scraper 27 and the lower surface of the upper lid 21. Then, when the developing sleeve 26 rotating at a high speed produces an air flow in the direction of the arrow, when the air flow hits the developer pool D ₁ , convection occurs in the opposite direction and the accumulated developer D and the spikes are continuously cut. The toner separated from the developer D is the upper lid 21.
20 formed by the lower surface of the developing sleeve and the peripheral surface of the developing sleeve 26.
From a, it leaks and scatters into the image forming apparatus. Then, the scanning optical system is contaminated, and the toner image to be developed and the relationship with the main body gear are adversely affected. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide a developing device in which the developer does not leak into the image forming apparatus.

[0010]

[Means for Solving the Problems]
It is achieved by either b or c.

(A) In a developing device of an image forming apparatus for applying toner to an electrostatic latent image formed on an image carrier to develop the electrostatic latent image, air is exhausted to a part of a developing device main body which forms a housing of the developing device. A developing device characterized in that a hole is formed and a filter for preventing developer leakage is provided in the air discharge hole.

(B) The developing device according to item (a), wherein the air discharge hole is provided in the developing device main body facing the upper side of the peripheral surface of the developing sleeve or the upper lid of the developing device main body.

(C) In item (a), a bottleneck is formed between the peripheral surface of the image carrier and the upper end surface of the developing device main body facing the peripheral surface, and the distance between the bottleneck is set to 3 mm or less. Characteristic developing device.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is a side sectional view showing the arrangement and configuration of an air discharge hole and a filter provided in a developing device of FIG. 1, a top view of FIG. 2 and an image forming apparatus of FIG. Description will be given with reference to a side sectional view showing the structure and a side sectional view showing the structure of the conventional developing device shown in FIG. However, the present invention is not limited to this embodiment. Each member of the developing device having the same function as the conventional one is represented by the same symbol.

Since the function and operation of the developing device 6 are exactly the same as those of the conventional device, the description thereof will be omitted and only the differences between the present invention and this invention will be described.

As shown in FIG. 3, an electrophotographic image forming apparatus 18 is provided.
A platen glass P for placing a document M is provided on the upper surface of the main body 1, and a scanning optical device 2 is provided below the platen glass P in the main body 1. The scanning optical device 2 includes a reciprocating document irradiation lamp 2a, a first mirror 2b, second and third mirrors 2c forming a V shape, a fixed lens 2d and a fourth mirror 2e. A photoconductor drum 3 is rotatably provided in the center of the inside of the main body 1 in the direction of the arrow, and in the periphery thereof, a belt electrode 4 for uniformly charging the photoconductor 3a along the rotation direction and a toner replenishing device. 5, a developing device 6 which is replenished with toner and has a developing sleeve 6a therein;
A transfer electrode 7, a separation electrode 8, a charge eliminating electrode 9, and a cleaning device 10 are sequentially arranged. Paper cassette 11,
Two types of recording papers of different sizes are housed in 11 'and set in the main body 1. 12 is a paper cassette 11
Is a first paper feed roller that feeds the recording paper stored in to a standby position before the second supply roller 13, and is a roller 12a that is rotated via a belt to prevent double feeding of the recording paper.
12a and a stop roller (also referred to as a separating roller) 12b. 13 is an appropriate timing so that the recording paper fed by the first paper feed roller 12 is temporarily stopped at the standby position, and then the leading edge of the visible image on the photoconductor 3a and the leading edge of the recording paper are aligned at the transfer position. The second paper feed roller 14 that feeds paper toward the transfer position again, and 14 is a guide plate for guiding the recording paper fed by the first paper feed roller 12 to the position of the second paper feed roller 13, It is opened and closed by operating a lever (not shown) so that the jammed paper can be taken out by inserting a hand. Reference numeral 15 is a conveying device that conveys the recording paper after transfer to a fixing position, and the fixing device 16 is a heating roller.
16a and pressure roller 16b. Reference numeral 17 denotes a paper discharge roller that discharges the recording paper after fixing to the outside of the main body.

When the copy button is operated in the above apparatus, the original M on the platen glass P is exposed and scanned by the scanning optical device 2, and an electrostatic latent image of the original M is formed on the photoconductor 3a of the photoconductor drum 3. It This electrostatic latent image is developed by the developing device 6.
Is converted into a visible image by the transfer electrode 7 and transferred to the recording paper fed from one of the paper feed cassettes 11 and 11 'of the main body 1. After the transfer, the recording sheet is separated from the photoconductor 3a by the separation electrode 8 and is fixed by the transport device 15.
The sheet is conveyed to 16, is fixed there, and is ejected by the ejection roller 17. In this way, desired toner images are successively recorded on the recording paper surface.

An air discharge hole which is a developer leakage preventing means provided in the developing device of the present invention and a filter are arranged and constituted as follows.

As shown in FIGS. 1 and 2, a large number of air discharge holes 30 are formed in a square shape having a predetermined size as shown in the figure at a position facing the peripheral surface of the developing sleeve 26 of the upper lid 21. twenty one
Are arranged at equal intervals in the longitudinal direction (the direction perpendicular to the paper surface of FIG. 1).

The filter member 31 is, for example, an elongated sheet-shaped member made of polyester fiber, and covers the air discharge hole 30 with a double-sided tape or the like on the upper surface of the air discharge hole 30 formed in the upper lid 21 without any gap. Pasted on.

Further, as shown in FIG. 1, the tip portion of the upper lid 21 facing the peripheral surface of the photosensitive drum 3 extends in the peripheral surface direction of the photosensitive drum 3 from the conventional position, and the inside is the peripheral surface of the developing sleeve 26. The developer leakage prevention wall 21a is formed in a concentric shape with a predetermined gap, and the outer side thereof is formed by a circular arc substantially concentric with the peripheral surface of the photoconductor drum 3 as shown in FIG. It is provided so as to face the peripheral surface of the body drum 3. The narrow path 32 formed by the outer surface of the leakage prevention wall 21a and the peripheral surface of the photosensitive drum 3 prevents the developer D and the toner in the developing device 6 from leaking into the image forming apparatus 18. The distance between the bottleneck 32 is set to 3 mm or less, preferably
It is set to around 1.3mm. With the air discharge hole 30, the filter member 31, and the developer leakage prevention wall 21a configured as described above, the filter member 31 completely collects the above-described air flow and the developer D scattered when the spikes are cut by the scraper 27. Then, only clean air is discharged from the developing device 6 in the direction of the arrow.

Therefore, the developer D and the toner are prevented from leaking from the developing device 6, and the inside of the image forming apparatus 18 is always kept clean. Even when the developer pool D ₁ described above does not exist, the air discharge hole 30 and the filter member 31 are extremely effective in preventing the developer D and toner from leaking, for example, against the toner scattering when the spikes are cut by the scraper 27. It is arranged not only at the above position but also at an appropriate place corresponding to the characteristics of the developing device 6. Further, the filter member 31 can be replaced at any time during predetermined maintenance or at an appropriate time.

In this way, a good toner image is always developed on the peripheral surface of the photosensitive drum 3.

[0024]

EFFECT OF THE INVENTION Due to the air discharge hole and the filter member provided in the developing device of the present invention, a developer pool generated in the developing device,
The developer scattered at the time of cutting the spikes was collected by the filter member and prevented from leaking into the image forming apparatus. Further, since the developer leakage prevention wall provided at the front end portion of the upper lid forms a narrow path with the peripheral surface of the photosensitive drum, the leakage of the developer can be further prevented.

[Brief description of drawings]

FIG. 1 is a side sectional view showing the arrangement and configuration of an air discharge hole and a filter provided in a developing device according to an embodiment of the present invention.

FIG. 2 is a top view of the above.

FIG. 3 is a side sectional view showing the configuration of the image forming apparatus.

FIG. 4 is a side sectional view showing a main configuration of a conventional developing device.

[Explanation of reference signs] 3 photoconductor drum 6 developing device 18 image forming device 20 developing device body 21 upper lid 21a developer leakage preventing wall 26 developing sleeve 27 scraper 30 air discharge hole 31 filter member 32 bottleneck D developer D ₁ developer pool

Claims (3)

[Claims] 1. In a developing device of an image forming apparatus for applying toner to an electrostatic latent image formed on an image carrier to develop the electrostatic latent image, an air discharge hole is provided in a part of a developing device body forming a housing of the developing device. And a filter for preventing developer leakage is provided in the air discharge hole. 2. The developing device according to claim 1, wherein the air discharge hole is provided in the developing device main body facing the upper side of the peripheral surface of the developing sleeve or the upper lid of the developing device main body. 3. A bottleneck according to claim 1, wherein a bottleneck is formed between the peripheral surface of the image carrier and an upper end surface of the developing device main body facing the peripheral surface, and the distance between the bottleneck is set to 3 mm or less. Characteristic developing device.