JPS63199382A - Electrostatic latent image developing device - Google Patents

Abstract

PURPOSE:To remove the cohesion of toner into fine recessed parts and to improve the supplying efficiency of toner to a developing sleeve by shaping the fine recessed parts formed on the surface of a toner feeding roller like grooves capable of escaping along the periphery of the roller. CONSTITUTION:When toner in a hopper 13 is carried to the toner feeding roller 10, the toner is entered into the fine recessed part 21 on the outer periphery of the roller 10 and the excess toner out of the carried toner is scraped by the tip contact part of a regulating blade 11. At that time, the toner filled in the recessed part 21 escapes along the groove-like recessed part 21 of the roller 10 by contact with a blade 11. On the other hand, the toner which is in contact with the surface 21a of the recessed part 21 is held by friction with the fine rugged part 20 on the surface of the roller 10 and carried in accordance with the rotation of the roller 10. The tip part of the blade 11 is pressed against the surfaces 22a of projection parts of the roller 10 and the quantity of toner passing the tip press-contact part of the blade 11 is always fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrostatic latent image developing device used in image forming apparatuses such as copying machines and printers.

(Prior Art) Conventionally, one of the above-mentioned developing devices includes a developing sleeve, a toner supply roller having minute recesses formed on its outer circumferential surface, and a regulating blade that presses against the outer circumferential surface of the toner supply roller, and the toner supply roller The toner held on the surface of the roller is conveyed based on its rotation, and is filled into the minute recesses by the pressure contact portion of the regulating blade, and is supplied to the carrier or developer held on the surface of the developing sleeve. is proposed in Japanese Patent Application Laid-Open No. 59-11.1663.111664.

(Problems to be Solved by the Invention) However, the minute recesses are simply recesses formed on a smooth surface by blasting, etching, or the like.

Therefore, as shown in FIG.
The toner (To
) receives resistance from the tip of the regulation blade (32) based on the rotation of the toner supply roller (30) in the direction of the arrow (P), the toner (TO) is transferred to the downstream end of the minute recess (31). They are pushed away and aggregate here.

However, this aggregated toner has poor dispersibility and cannot make good contact with the carrier, so even if it is supplied to the surface of the developing sleeve, it falls from there and damages surrounding equipment.
This has caused problems such as Q staining and adhesion to the photoreceptor, appearing as spots on copied images, resulting in a significant deterioration of image quality.

Further, when the minute recesses (31) are formed by blasting, the recesses (31) vary in size, so that the pressure contact state of the regulating blade (32) becomes uneven. As a result of the rotation of the toner supply roller (30), the tip of the regulation blade (32) shakes, resulting in a gap between the regulation blade (32) and the surface of the toner supply roller (30), from which the toner is regulated. The problem is that the toner flows out without being received, resulting in uneven supply of toner.

(Means for solving the problems) The present invention has been made to solve the problems mentioned above.
In the developing device, the surface micro-recess of the toner supply roller has a shape (74) in which the toner filled in the micro-recess can escape along the circumferential surface of the toner supply roller when it comes into contact with the regulation blade, and the micro-recess This prevents the toner from clumping inside.

(Example) Hereinafter, the present invention will be described with reference to the accompanying drawings showing one example.

In FIG. 1, (1) is a photoreceptor drum, and the photoreceptor drum (]) can be driven to rotate in the direction of arrow (a).

(2) is a developing device according to the present invention, (3) is a developing tank,
The developer tank (3) is composed of a casing (4) and a cover (5).

A developing sleeve (6) facing the photoreceptor drum (+) is housed in the front part of the developing tank (3), and this developing sleeve (6) is a cylindrical body made of a non-magnetic conductive material, not shown. It can be rotated in the direction of arrow (b) by a drive source.

A magnetic roller (7) is fixed inside the developing sleeve (6), and the magnetic roller (7) has a plurality of magnets with magnetic poles extending in the axial direction, and N and S poles on the outer periphery. are arranged alternately.

A height regulating member (
8), the tip of which faces the outer peripheral surface of the developing sleeve (6) with a predetermined height regulating gap, and a developer reservoir (9) on the upstream side in the rotational direction of the developing sleeve.
is formed.

A toner supply roller (10) is located behind the developing sleeve (6).
) is arranged to face the developing sleeve (6) with a predetermined supply gap therebetween.

This toner supply roller (10) is connected to the developing sleeve (6).
It is made of non-magnetic conductive material in the same way as the
A fine concavo-convex pattern (20) as shown in FIG. This allows rotational drive in the direction of arrow (c).

The minute unevenness pattern (20) is formed by the toner supply roller (I
O) has a continuous spiral groove shape along the outer peripheral surface, and the width (B, ) of the recess (21) is 2500 μm.
, the width (B2) and height I() of the convex portion (22) are 150 μm and 10 to 50 μm, respectively, and the convex portion (22)
The surface (22a) has a mirror finish, and the recess (22a) has a mirror finish.
On the surface of 1), finer unevenness of 5 to 10 μm is formed.

The above-mentioned minute unevenness pattern (20) is first created by etching the surface of the toner supply roller (10) into a depression (21).
, After forming the convex part (22), finer minute irregularities are formed by blasting from above, and then the convex part (22) is formed.
2) is formed by polishing the surface to a mirror finish.

Further, a toner regulating blade (1) attached to the casing (4) is attached to the upper outer peripheral surface of the toner supply roller (10).
1) is in pressure contact, and a toner spilling member (12), which is also attached to the casing (4), is in pressure contact with the lower outer peripheral surface.

Toner supply roller (10), regulation blade (11).

A toner hopper (13) is formed at the rear of the developer tank (3) partitioned by a toner spilling member (I2), and conveyance paths (14) and (15) formed in parallel therewith are provided with conveyance blades ( 16), (17) are arrows (d), (e)
It is arranged so that it can rotate in the direction.

The developing device (2) having the above configuration has a toner hopper (
14) is loaded with toner, and a starter in which toner and carrier are mixed at a constant ratio is loaded into the developing sleeve (6) and the developer reservoir (9). Note that only the carrier may be loaded instead of the starter.

Further, the toner and the carrier are charged to opposite polarities when they come into frictional contact with each other, and in this embodiment, the toner is positively charged and the carrier is negatively charged.

With the above settings, the developing sleeve (6
),) toner supply roller (10), conveyance blade (16), (
17) starts, first the toner hopper (13)
Now, based on the rotation of the conveyor blades (+6) and (17),
The toner therein is gradually conveyed towards the toner supply roller (10). Note that at this time, the toner lumps are crushed by the conveying blades (16) and (t7).

Toner supply roller (1) facing inside of toner hopper (13)
0), the toner conveyed from the rear is taken into the micro recesses (21) on its surface and conveyed in the direction of arrow (c), and excess toner is removed at the tip contact portion of the regulating blade (11). scraped off.

At this time, the toner filled in the minute recess (21) is subjected to a resistance force in the direction opposite to the rotational direction of the toner supply roller (10) due to contact with the regulation blade (11). 21) is continuous in a spiral shape, the toner can escape along the groove-like recess (21) and will not aggregate.

On the other hand, the toner that comes into contact with the surface (21a) of the minute recess (21) is held by friction with the finer unevenness formed on the surface, and as the toner supply roller (10) rotates, the toner is held as shown by the arrow (c). conveyed in the direction.

In addition, since the tip of the regulation blade (11) comes into pressure contact with the mirror-finished convex surface (22a) of the toner supply roller (10), the tip of the regulation blade (11) always maintains a close contact without wobbling. The amount of toner passing through the pressure contact portion at the tip of the regulating blade (11) is always constant.

The toner is slightly charged by contact with the regulating blade (11), and one or two layers of charged toner are deposited on the surface of the toner supply roller (10) that has passed through the contact portion of the toner regulating blade (11). A layer is formed.

On the other hand, on the surface of the developing sleeve (6), the developer is conveyed in a magnetic brush state in the direction of arrow (b) along the lines of magnetic force generated from the magnet of the magnetic roller (7), and the toner charged thin layer is the part (Y) facing the developing sleeve (6)
(hereinafter referred to as the "supply area"), the developer is scraped off by the magnetic brush-like developer.

Note that since the toner on the toner supply roller (10) maintains its original powder state without agglomerating, it is easily scraped off by the magnetic brush.

By the way, in the supply area (Y), not only the above-mentioned toner supply operation but also a collection operation in which the toner on the developing sleeve (6) is collected to the toner supply roller (10) is also performed in parallel. The excess toner on top is collected into the toner supply roller (10) and further into the toner hopper (13).

The toner supplied onto the developing sleeve (6) is transported in the direction of arrow (b) based on the rotation of the developing sleeve (6), and during this time it comes into contact with the carrier and the amount of charge on the toner increases. . Note that since the toner supplied to the surface of the developing sleeve (6) is not aggregated, it quickly disperses on the developing sleeve (6) and makes good contact with the carrier. Therefore, it may be transported on the developing sleeve (6) uncharged, it may detach from the surface of the developing sleeve (6) during transport and adhere to the surface of the photoreceptor drum (1), or it may contaminate peripheral equipment. There's nothing to do.

Next, the developer is applied to the portion (X) facing the photoreceptor drum (1) (
When reaching the development area (hereinafter referred to as a "development area"), toner is supplied to the electrostatic latent image area formed on the surface, and the electrostatic latent image area is visualized.

The developer that has passed through the development area (X) is transferred to the height regulating member (8).
), the developer is cut into ears here and most of the developer falls into the developer reservoir (9).

This fallen developer is mixed with the carrier and developer staying here while forming a vortex in the direction of the arrow.
Some of the developer is again held on the surface of the developing sleeve (6) and transported to the supply area (Y), where the toner supply and collection operations are performed again.

Note that the consumption pattern on the developing sleeve (6) in which toner is consumed in the developing area ('X') is that first, the developer is mixed and stirred in the developer reservoir (9), and then the toner is consumed on the developing sleeve (6). ) After the developer density on ) is averaged, the missing amount is replenished from the toner supply roller (] 0) in the subsequent supply area (Y), and it is completely erased by the time it passes through the supply area (Y). .

In the above description, the fine unevenness pattern (20) on the surface of the toner supply roller (10) is in the shape of a groove continuously formed along the outer circumferential surface, but the pattern is not limited to this. It may be a groove shape formed along the outer periphery of a cross section cut perpendicularly or obliquely to the axis, or a meandering shape.In short, the toner taken into the minute recesses (2I) may be Regulation blade (
Any pattern may be used as long as it can escape along the recess (21) even if subjected to the resistance II).

(Effects of the Invention) As is clear from the above description, in the developing device according to the present invention, the shape of the minute recess formed on the surface of the toner supply roller is controlled by the toner filled in the minute recess. The toner supply roller has a groove shape that allows the toner to escape along the circumferential surface of the toner supply roller when it comes into contact with the blade.

Therefore, the toner on the surface of the toner supply roller does not aggregate in the minute recesses due to the resistance received from the regulation blade, and is transported to the supply area in its original powder state, which not only improves the efficiency of supply to the developing sleeve. It is quickly dispersed in the developing sleeve, makes good contact with the carrier, and is charged.

Therefore, it is supplied to the developing sleeve in an uncharged state, detaches from the surface of the developing sleeve and adheres to the surface of the photoreceptor, and appears as fog or spots on the background of the image, or is scattered around and attached to other equipment. It is possible to maintain good image quality of the copied image without contaminating the copying machine, and to maintain the interior of the copying machine or the like in a clean state.

In addition, since the tip of the regulation blade stably contacts the convex part of the toner supply roller, the amount of toner passing through the part facing the regulation blade is stabilized, and excess toner is supplied to the surface of the developing sleeve. There is no.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the developing device, Fig. 2 is a perspective view of the toner supply roller, Fig. 3 is an enlarged perspective view of a minute recess of the toner supply roller, and Fig. 4 is an enlarged view of the conventional toner supply roller and regulation blade. It is. ■...Photosensitive drum, 2...Developing device, 3...
Housing, 6... Developing sleeve, 7... Magnetic roller, 8 Brush height regulating member, 9... Developer reservoir, IO... Toner supply roller, 11... Regulation blade, 13... Toner hopper, 16.17... Conveyance blade, two... Minute unevenness pattern, 21... Concave portion, 22... Convex portion.

Claims (1)

[Claims] (1) A developing sleeve, a toner supply roller having minute recesses formed on its outer circumferential surface, and a regulating blade that presses against the outer circumferential surface of the toner supply roller, and based on the rotation of the toner supply roller, the regulating blade In an electrostatic latent image developing device that fills the minute recess with toner using a pressure contact portion and supplies the toner to the surface of the developing sleeve, the minute recess is filled with toner,
An electrostatic latent image developing device characterized in that the toner filled in the minute recesses has a groove shape that allows the toner to escape along the circumferential surface of the toner supply roller when it comes into contact with the regulation blade.