JPS628176A - Dry type developing device - Google Patents

Abstract

PURPOSE:To supply toner which has superior electrostatic charging property to a developing sleeve and to prevent a developer from sticking on agitator blades by using a developer conveyor roller which has blade parts provided on its rotating shaft in the opposite directions alternately at a specific angle, and providing a deficit part to each blade part. CONSTITUTION:When the support shaft 51 is driven to rotate as shown by an arrow (a), the developer 56 in a conveyance path 31 is conveyed as shown by an arrow A by being given an axial propellent force by the rotation of the blade parts 53 and even if the developer 56 is scooped up by the blade parts 53 temporarily, it falls from deficit parts 53e by gravitation. Thus, those processes are repeated to convey the developer as shown by an arrow A. The developer is scooped up and falls alternately by the blade parts 53 frequently, so the agitation efficiency of the developer is improved greatly. While the developer is conveyed in the conveyance path 32 as shown by an arrow B, part of it is scooped up by a bucket 42 and supplied to the outer peripheral surface of a developing sleeve 21.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a dry developing device used in electrophotographic copying processes and the like.

(Prior Art) In general, a dry-type developing device conveys developer (generally consisting of a mixture of carrier and toner) held on the outer circumferential surface of a developing sleeve in the circumferential direction, The electrostatic latent image formed on the surface of the electrostatic latent image carrier is developed in a development area facing the image carrier.

In this case, the developer is supplied to the rear side of the developing area of the developing sleeve, but at the time of this supply, the developer must be sufficiently mixed and stirred, and the toner must be sufficiently abrasively charged. be.

In particular, in today's world where copying machines are required to be faster, the amount of toner consumed per unit time increases.
The amount of charge of the toner must be increased to a level suitable for development by stirring.

Therefore, in order to efficiently mix and stir the developer, a developer conveyance path is formed on the back side of the developing sleeve, and a developer conveyance roller having a screw-like blade is disposed in the conveyance path. A developer has been proposed in which the carrier and toner are conveyed while being mixed and stirred by the developer conveying roller.

(Problems to be Solved by the Invention) However, even with the above-mentioned method, the developer once scooped up by the blades of the developer transport roller is transported in the axial direction as it is, or is affected by electrostatic force and interparticles. Since the developer remains attached to the blade portion due to force or the like, the developer is not stirred and a sufficient amount of toner charge cannot be obtained.

In order to solve this problem, there is a method of increasing the charging performance of the toner by lengthening the conveyance path, but this leads to an increase in the size of the developing device, and in today's current situation where devices are being made smaller. It goes against the grain.

(Means for Solving the Problems) The present invention has been made to solve the problems of the conventional dry-type developing device. In addition to using a blade having a blade portion provided in the blade, a cutout portion is provided in the blade portion.

(Example) Hereinafter, an example of a dry developing device according to the present invention will be described with reference to the accompanying drawings.

In FIG. 1, this dry developing device has a magnetic roller (22
) with a built-in developing sleeve (2I).
), a packet roller (4) and a developer transport roller (5).
) and a toner storage section (3).
6), and transports the toner in the toner storage section (6) to the transport section (
3), and a replenishment section (7) for transporting the components to the casing (1).

The developing sleeve (21) is made of a non-magnetic conductive material (for example, aluminum) formed into a cylindrical shape, and minute irregularities are formed on the outer peripheral surface by sandblasting, so that it can be rotated in the direction of arrow (e). It faces the surface of a photoreceptor drum (not shown).

The developer circulation conveyance section (3) includes a developer mixing and stirring conveyance path (31) formed by curving the bottom of the casing (1) downward.
) and a developer supply conveyance path (32), which are separated by a partition plate (33) rising from the bottom of the casing (1), and have openings (33) at both ends of the partition plate (33).
a), (33b) Nite communication shite.

The conveyance path (32) is parallel to the developing sleeve (21),
The conveyance path (3K) is arranged at a slight inclination so that it is lower on the left side in FIG. 1 and higher on the right side than the conveyance path (32), and the opening (33a) is communicated with the slope surface (34). and,
This inclined surface (34) has an angle equal to or larger than the repose angle of the developer so that the developer can easily flow.

The packet roller (4) has two hexagonal support plates (41
A packet (42) having a notch at the bottom is bridged between the rollers (one of which is not shown), and a blade plate (43) is attached to the inside of the packet (42).
) is installed so as to be rotatably driven in the direction of arrow (b) within the developer agitation conveyance path (32) via a support shaft (44) passing through the inside.

Based on the rotation in the direction of arrow (b), this packet roller (4) scoops up the developer with the side piece of the packet (42) and supplies it to the outer peripheral surface of the developing sleeve (21). It has a function of conveying in the direction of arrow (B) using the wing plate (43).

As shown in detail in FIGS. 2 to 5, the developer transport roller (5) has a support shaft (5o) fitted with a large number of blade members (51) having the same shape, and is indicated by the arrow ( It has a function of mixing and stirring the developer while conveying it in the direction of arrow (A) based on the rotation in the a) direction.

The blade member (51) has a roughly cylindrical main body (52) provided with a blade part (53) as described below at a predetermined angle (θ) (see Fig. 3) with respect to the axis of the main body (52). It is an integrally molded product made of resin. The main body (52) has semicircular protrusions (52a) formed at both end halves, and grooves (52a) extending in the axial direction from the end faces at the center of each protrusion (52a).
b) is formed, while the blade part (53) is
As shown in FIG. 4 and FIG. A cutout (53e) is formed in a substantially semi-elliptical flat plate.

In addition, the main body (52) having the protrusion (52a), the main body (
52) and the axial length of the blade portion (53) are L+, respectively.
Let Lx and La be these beams, + L, <2L3
The relationship between the blade members (51) and the spindles (5) is such that the blade parts (53) are alternately located on opposite sides.
0), the main body protrusion (52a) engages with the adjacent main body protrusion (52a), and the adjacent parts of the blade parts (53) overlap at the overlapping part (X) (see Fig. 4). They are butted against each other, so that a gap (S) is created between the end faces of the main body (52).

Note that the gap (S) is defined by the fact that the series of blade members (51) fitted on the support shaft (50) has an error in the length in the axial direction due to the cumulative dimensional tolerance of each blade member (51). Also, by forcibly pressing and deforming the stirring blade portion (53) in the axial direction within the cumulative range of the gap (S), a developer conveying roller (5) of a predetermined size can be formed. can.

Note that the blade members (51) located at both ends are attached to the support shaft (5
A split pin (55) is press-fitted into the through hole (54) provided in
), positioning in the axial direction is achieved, and the rotational force of the support shaft (50) is transmitted via the pin (55), and the blades mutually engage with this at the protrusion (52a). The member group rotates integrally with the support shaft (50).

The toner storage section (6) is equipped with a stirring device (62) in a toner hopper (61) located behind the conveyance path (31), and a replenishing toner is provided in the upper part of the toner hopper (61). A toner cartridge (not shown) prefilled with toner is removably attached, and the hopper (61) is replenished with replenishing toner.

The replenishment section (7) includes the conveyance path (31) and the toner storage section (
6), and the supply section (7) and the conveyance path (31) are separated by a partition plate (35).

A replenishment roller (71) is installed in the replenishment section (7).
The supply path (74) located at the bottom of the container 61) can be rotated in the direction of arrow (d). Also, this supply route (74
) is connected to the conveyance path (31) through a toner replenishment slope (75).

This inclined surface (75) has an angle equal to or greater than the angle of repose of the toner so that the toner can easily flow.

The operation of the developing device having the above configuration will be described below.

First, the toner replenished into the toner hopper (61) of the toner storage section (6) is agitated by the agitation device (62) and is moved through the replenishment path (7I) based on the rotation of the replenishment roller (7I) in the direction of the arrow (d). 74) in the direction of the arrow (D), and is guided from the left side in the figure to the inclined surface (75) to the conveying path (3).
1) is supplied upstream.

Then, the developer is transferred to the developer transport roller (5) as indicated by the arrow (a).
Based on the rotation of the packet roller (4) in the direction of arrow (b), the packet is transported in the direction of arrow (A) within the transport path (31) and reaches the downstream end of the transport path (31). The developer is guided from the opening (33a') to the inclined surface (34) and moves to the conveyance path (32). Next, this developer is conveyed in the direction of arrow (B), reaches the downstream end of the conveyance path (32), is scooped up by the scooping plate (45) of the packet (42), and passes through the opening (33b). From there, it moves to the conveyance path (31), and is circulated through the conveyance paths (31) and (32). In this case, each conveyance path (31).

Since the conveyance level at the downstream end in the conveyance direction of (32) is set higher than the downstream conveyance level of the other conveyance paths (32) and (31), the developer is transferred to each conveyance path (31),
(32) smoothly opens from (33a) and (33b) to the other conveyance path (3
2) and (31), especially the developer supply and conveyance path (3).
The deviation of the developer in 2) does not occur.

Here, the developer conveying operation by the developer conveying roller (5) will be explained based on FIG. 6.

When the support shaft (51) is rotationally driven in the direction of the arrow (a), the developer (56) in the conveyance path (31) is given an axial driving force by the rotation of the blade portion (53), and moves in the direction of the arrow (A). ) direction, and even if the developer (56) is once scooped up by the blade portion (53), the defective portion (53e
) falls downward under its own weight. Thereafter, such steps are repeated while being transported in the direction of arrow (A).

In this way, since the developer (56) is frequently scooped up and dropped by the blade (53), the agitation efficiency of the developer is greatly improved.

Further, while the developer is being transported in the direction of arrow (B) within the transport path (32), a portion of the developer is scooped up by the packet (42) and supplied to the outer peripheral surface of the developing sleeve (21). . Then, since the developer is not unevenly distributed in the conveyance path (32), the developer is supplied to the developing sleeve (2).
1) It is uniform over the axial direction.

The developer held on the outer periphery of the developing sleeve (21) is conveyed on the outer periphery in the direction of arrow (e) based on the rotation of the developing sleeve (21) in the direction of arrow (e).
The electrostatic latent image formed on the surface of the photoreceptor is developed in a development area facing the photoreceptor drum.

Furthermore, new toner is replenished from the toner container (6) to the upstream side of the conveyance path (31), and is mixed and stirred while being conveyed in the direction of arrow (A) along with the existing developer within the conveyance path (31). fully charged.

In the embodiment described above, the blade portion (53) of the blade member (51) is formed by cutting out a semi-elliptical flat plate blade from the outer circumference in the axial direction to form a defective portion (53e). However, as shown in FIG. 7, the outer periphery may be left intact and a defective portion (53r) may be formed inside. The present invention is not limited to the above embodiments, as long as it is possible to obtain sufficient stirring properties without impairing the properties.

Further, in the above embodiment, the developer conveying roller (5) is a blade member (
51) are formed by fitting a plurality of them onto the support shaft (50), but the present invention is not limited to this. The developer conveying roller may be integrally molded, or may be divided into two parts in the axial direction, These may be integrated.

Furthermore, the developer conveying roller may be formed by integrating the blade members (51) by known means without fitting the blade members (5) onto the spindle (50).

Furthermore, as long as the conveying performance of the developer conveying roller (5) is not impaired, a plurality of blade portions may be provided in alternately opposite directions, and the blade portions (53
) do not necessarily have to be provided alternately in opposite directions for each sheet.

(Effects of the Invention) As is clear from the above description, according to the dry developing device according to the present invention, the developer conveying roller has blade portions provided alternately in opposite directions at a predetermined angle to the rotating shaft. In addition, the blade of the developer conveying roller is provided with a defective portion.

Therefore, the developer frequently repeats the scooping operation by the blade portion and the falling from the defective portion, and by increasing the mixing and stirring efficiency, it is possible to supply toner with sufficient chargeability to the developing sleeve. Developer does not adhere to the stirring blade.

That is, it is possible to improve the stirring efficiency without significantly reducing the conveying force.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of a dry developing device according to the present invention, FIG. 2 G is a perspective view showing an embodiment of a developer conveying roller, and FIGS. A side view, a front view, a plan view, FIG. 6 is a perspective view showing the developer conveyance state by the developer conveyance roller, and FIG. 7 is a front view showing another embodiment of the blade member. L... Casing, 2... Developing section, 3... Developer circulation conveyance section, 4... Packet roller, 5... Developer conveyance roller, 6... Toner storage section, 7...・Supply Department,
51...Blade member, 52...Main body, 53...Blade portion, 53e...Deletion portion.

Claims (1)

[Claims] (1) Mixing the developer with a developer conveying roller having blades arranged alternately in opposite directions at a predetermined angle on the rotating shaft;
What is claimed is: 1. A dry type developing device configured to transport developer to a developing section while stirring the developer, characterized in that a defective portion is provided in a blade portion of the developer transporting roller.