JPH01319073A - Bucket roller for developing device - Google Patents

Abstract

PURPOSE:To improve the carried and scrapped-off properties of a developer by providing flexible projecting scraping-off members on the bucket of a bucket roller at positions facing both end sections of developing sleeves and, at the same time, escape holes in the vicinity of the members. CONSTITUTION:Flexible projecting scraping-off sections 60 which are brought into contact with or approximated to the wall face of a stirring tank 46 are provided on the bucket 54 of a bucket roller 51 at positions facing both end sections of developing sleeves 37 and 39 and, at the same time, escape holes 61 are pierced in the vicinity of the members 60. As a result, the developer which is separated and recovered from the same-polarity magnetized sections S2 and S3 on both end sections of the sleeves 37 and 39 is scraped off by means of the member 60 and fetched into the bucket roller 51. Moreover, when the collected developer is compressed and the pressure inside the developer becomes higher, a part of the developer flows out from the roller 51 through the holes 61. Therefore, the carried and scraped-off properties of the developer are improved at both end sections of the developing sleeves.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a bucket roller of a developing device used in a copying machine or the like.

(Prior Art) Conventionally, as shown in FIG. 7, for example, a developing device includes a developing sleeve (81) that faces a photoreceptor drum (100) in a developing device (80), and a developing sleeve (81) that faces a photoreceptor drum (100). The bucket roller (8
2). The bucket roller (82) of this developing device has an abbreviated or U-shaped bucket (83) arranged around its outer periphery, and the developing sleeve (81)
) is taken in and mixed with the developer contained in the developer stirring tank (84) to improve the potential of the toner, and then transferred to the developing sleeve (8I).
It is designed to be supplied to

(Problem to be solved by the invention) However, in the same polar magnetized parts (St) and (ss) at both ends of the developing sleeve (81), the magnetic poles (S,) and (N,)
The lines of magnetic force between them are formed to wrap around the end face of the magnetic pole body, disrupting the magnetic field (see Figure 6), and the bucket roller (
Since the rotational pressure of the bucket (83) of 82) and the pressure due to the developer's own weight are applied, there is a problem that the conveyance to the stirring tank (84) is poor.

Further, since there are flanges formed at a predetermined thickness to support the bucket (83) at both ends of the bucket roller (82) that are opposite to both ends of the developing sleeve (81), this thickness Since the flow of the developer scraped off within the corresponding range is obstructed by the flange, there is a problem that the scraping performance of the developer separated from the developing sleeve (81) and collected is poor at this part. Ta.

Furthermore, there was a problem in that the developer could become clogged between the flange and the wall of the stirring tank (84), or it could flow to the side of the flange, causing the bearing to enter the area and increasing the driving torque of the bucket roller (82). .

As a result, developer tends to accumulate at both ends of the developing sleeve, causing overflow or backflow.

Therefore, it is conceivable to increase the length of the developing sleeve (81) so that the developer can be collected and supplied in a portion not affected by the disturbance of the magnetic field. However, this has the disadvantage that the developing device becomes larger.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a bucket roller of a developing device that has good developer conveyance and scraping properties at both ends of a developing sleeve.

(Means for Solving the Problems) In order to achieve the above object, the present invention takes in the developer collected from the developing sleeve and mixes it together with the developer stored in the developer stirring tank to form the developing sleeve. In the bucket roller of the developing device, a flexible scraping member whose tip contacts or approaches the wall surface of the stirring tank is protrudingly provided at a position facing both ends of the developing sleeve of the bucket of the bucket roller. An escape hole is provided near the scraping member.

(Function) According to the above configuration, the developer that is separated and collected from the same-polarity magnetized portions at both ends of the developing sleeve is scraped off by the scraping member and taken into the bucket roller. Furthermore, when the scraped developer is compressed and the pressure increases, a portion of the developer flows out of the bucket roller through the escape hole.

(Example) The present invention will be described below with reference to the accompanying drawings.

(2) Structure of developing device fi) Schematic structure FIG. 1 shows a developing device (1) according to the present invention, and this developing device (1) roughly consists of a toner replenishing device (2) and a developing device (3). It is configured.

[ii) Toner replenishing device (2) In the toner replenishing device (2), the cartridge accommodating section (4)
A toner cartridge (15) is installed in the.

The cartridge accommodating portion (4) has a rear wall (7), a support member (6a), ( 6b), (
6C) across the rack, supporting members (6a), ~, (6c)
supports a substantially semicircular bottom plate (9). Note that the bottom plate (9) has its tip locked to the arm (11),
The arm (11) has a shaft (10) on the side plates (5), (5).

It is rotatably attached via (lO). Further, one end of a spring (12) is locked to the bottom of the bottom plate (9) and biased in the direction of arrow (a), and when the toner cartridge (5) is not installed, the spring (12) It moves in the direction of arrow (a) by the biasing force to close a toner supply port (27) of the developing device (3), which will be described later.

The toner cartridge (15) has a stirring blade (18) inserted through a support shaft (17) into a cylindrical body (16) with both ends closed.
The main body (16) has an opening (19) formed along the axial direction.

The toner cartridge (15) has side plates (5), (5)
), the support shaft (17) is lowered along the guides I (13), (13) formed in Mouth (2
7).

When the toner cartridge (15) is installed, the bottom plate (9)
) moves in the direction of the arrow (ao) about the shaft (10) against the biasing force of the spring (12), and the toner supply port (27) is opened.

Note that the toner cartridge (15) is prevented from falling off by a lock portion (8) provided on the rear wall (7).

Further, when the toner cartridge (15) is installed, the handle (4a) located in the cartridge accommodating portion (4) is rotated in the direction of arrow ch> and placed in a position out of the way.

[iii) Developing device (3) The developing device (3) is roughly composed of a toner supply section (20), a developing section (35), and a developer stirring section (45).

(B) Toner supply section (20) The toner supply section (20) receives toner supplied from the toner cartridge (15) of the toner supply device (2) and supplies it to the development section (35). It is.

In the toner supply section (20), between the bottom frame (21) constituting the developing device (3) and the partition walls (49) and (50) that partition the developer stirring section (45), A toner supply roller (22) is arranged at the front, and a toner hopper (25) having a stirring blade (26) is formed at the rear.

The toner supply roller (22) has minute irregularities formed on its outer circumference, and partition walls (
50), the blade (2) attached to the bottom frame (21)
3) The tips of the toner outflow prevention plates (24) are pressed into contact with each other.

Note that the toner supply roller (22) is connected to an AC power source (31).
) and the recovery bias voltage (Vs
=Vr ta s +Vs s ) is applied.

The toner hopper (25) is directed diagonally upward (28)
is connected to the toner supply port (27) via the toner supply port (27), and
28) is rotatably provided with a toner empty detection device (30). In addition, a toner spill prevention sheet (29) is attached to the lower edge of the toner supply port (27).
The tip contacts the outer periphery of the toner cartridge (15) to prevent toner from spilling out from the gap between the developing device (3) and the toner cartridge (!5).

(b) Developing section (35) The developing section (35) receives and takes the toner supplied from the toner supply section (20), and while conveying the toner and carrier, it passes through the photosensitive drum (100), which is an electrostatic latent image carrier. ) toner is supplied to the electrostatic latent image formed on the surface of the image.

In the developing section (35), the space formed between the bottom frame (21) and the sleeve cover (36) includes a developing sleeve (37) at the bottom and another developing sleeve (39) at the top.
), the lower developing sleeve (37) faces the toner supply roller (22) with a predetermined minute gap, and the upper developing sleeve (39) has a sleeve cover (36) on the top. The height regulation plate attached to the rear (
The tips of 41) are opposed to each other with a predetermined height regulating gap.

In addition, the developing sleeves (37) and (39) are connected to a DC power source (4).
2), from (43), the developing bias voltage (Vb l), (
Vb t) are applied respectively. Further, the developing sleeves (37) and (39) include the developing sleeves (37) and (39).
) and (39), magnet bodies (38) and (40) are housed in a fixed state.

The magnet body (38) has magnetic poles (N1) to (N3) and (Sυ
~(S3), and the magnetic pole (Sl) is attached to the photoreceptor drum (10
0), the magnetic pole (S, ) is arranged in the facing part (B) with the toner supply roller (22), and the magnetic pole (S3)
.

(N3) is arranged adjacent to both sides of the position (F) closest to the developing sleeves (37) and (39), and the magnetic pole (N1)
and (N,) are arranged between the magnetic poles (Sl) and (S,) and between the magnetic poles (S,) and (S,), respectively.

The other magnet body (40) has magnetic poles (N,) to (N3)
and (Sl) to (S4), the magnetic pole (N,) is arranged at the part (D) facing the photoreceptor drum (100), and the magnetic poles (S,) and (S,) of the same polarity are adjacent to each other. and developer stirring section (45
), and the magnetic poles (S,), (N,) are opposite to the magnetic poles (N3) and (N) of the magnetic pole body (38) on both sides with respect to the position (F) closest to the sleeve. The magnetic poles (N,) are arranged adjacent to each other so that the height regulating plate (4
1), and the magnetic pole (S,) is located near the opposing part of
It is located between (N3) and (N,).

Further, at both ends of the upper developing sleeve (39), there is an area extending between the developing sleeve (39) and the bucket roller (51) and from the height regulating plate (41) to the vicinity of the tip of the partition wall (50). Covers (70), (70) covering the developing sleeve (39) are provided at regular intervals from the surface of the developing sleeve (39).

These covers (70), (70) cover the bucket roller (5).
This prevents the developer supplied from 1) to the developing sleeve (39) from adhering to the developing sleeve (39) along the direction of the arrow (■).

This prevents the rotational pressure of the bucket roller (51) and the pressure due to the developer's own weight from being applied to the same-polarity magnetized portions (S t), (S , +) at both ends of the developing sleeve (39). Collecting of developer is suppressed.

(c) Developer stirring section (45) The developer stirring section (45) mixes the toner supplied from the toner supply section (20) to the developing section (35) with the developer whose toner concentration has decreased. The developer is raised to a predetermined concentration and a developer suitable for development is prepared.

In the developer stirring section (45), the stirring tank (46) is formed behind the developing sleeve (39), with an upper frame (47) at the top and partition walls (49) and (5) at the back and bottom.
0), which accommodates a bucket roller (51), and the front part of the partition wall (50) is covered with a developing sleeve (3).
7) and (39) are opposed to each other.

The bucket roller (51), as shown in FIG.
Flanges (53), (53) are fixed to a drive shaft (52) rotatably supported at both ends by side plates (5), (5), and four buckets are placed between the flanges (53), (53). (54
) was constructed.

As shown in Fig. 3, this bucket (54) is made by bending a rectangular plate into a crank-shaped cross section, and has a scraping part (55) which is a side end part and a guide part which is a flat part in the figure. (56) and
A collision part (57) that stands up vertically from the guide part (56), and a plurality of openings (58) formed in the longitudinal direction at the part where the guide part (56) intersects with the collision part (57).
It was formed by And this bucket (54
) is installed so that the scraping part (55) faces the rotational direction (g) of the bucket roller (5I) and is close to the partition walls (49) and (50), as shown in FIG. ing.

Further, as shown in FIG. 4, among the buckets (54), the guide portions (56) of the pair of opposing buckets (54), (54) are provided with scraping portions as shown in FIG. (55
) A plurality of inclined guide plates (59) are erected in the longitudinal direction. This pair of buckets (54), (
The inclined guide plate (5) of one of the buckets (54)
9) and the inclined guide plate (59) of the other bucket (54) are arranged in directions that intersect with each other, and the bucket roller (54)
The developer in the chamber is circulated in the axial direction based on its rotation.

As shown in FIG. 2, the outer peripheral edges of the flanges (53), (53) have a plate thickness T1 of the non-attached portion of the bucket (54) that is thinner than a plate thickness T of the attached portion of the bucket (54), and Moreover, an inclined portion (53a) is formed toward the inside. Further, the portion of the bucket (54) that intersects with the scraping 111 ((55)) is a wedge-shaped take-in portion (53b) that is cut out so as to be inclined inward.

Both ends of the bucket (54), that is, the developing sleeve (39)
As shown in FIG. 2, a scraping member (60
) is provided protrudingly. This scraping member (60) is a thin plate such as Mylar film that is softer and more flexible than the partition walls (49) and (50), and is made of a thin plate such as Mylar film.
3) and (53) have a width W greater than or equal to the plate thickness T3, and the tip is a partition wall (49).

(50). Also,
A trapezoidal escape hole (61) is provided in the guide portion (56) of the bucket (54) near the scraping member (60) and at the back of the intake portion (53b) of the flange (53).

On the other hand, the lid (4) of the upper frame (47) is placed in the stirring tank (46).
8) is opened and a starter containing toner and carrier mixed in a predetermined ratio is loaded.

Further, a two-component developer containing a mixture of toner and carrier is held on the outer periphery of the developing sleeves (37) and (39).

(2) The developing device (1), which has a configuration above the operation of the developing device, is equipped with an agitating blade (18) when installed in an image forming apparatus such as a copying machine.

(26), toner supply roller (22), developing sleeve (
37), (39), and a bucket roller (51) are each drivingly connected to a drive system (not shown).

When the developing device (1) starts driving, the stirring blade (18) moves in the direction of the arrow (b) in the toner cartridge (15).
The toner rotates in the direction of the opening (
19), the toner is fed into the path (28) via the toner supply port (27).

The toner sent to the toner hopper (25) is transported by a stirring blade (
26), the toner is mixed and conveyed forward while being mixed based on the rotation in the direction of the arrow (d), and is held on the surface of the toner supply roller (22) in the area (A) near the outer circumference of the back surface of the toner supply roller (22). Based on the rotation, it is transported in the direction of arrow (C), and the amount of transport is regulated at the portion facing the blade (23). The toner scraped off from the outer periphery of the toner supply roller (22) by the tip contact portion of the blade (23) stays in the toner hopper (25). On the other hand, the blade (
The toner that has passed through the tip contact portion of the developing sleeve (37) is conveyed to the toner supply area (B) where the developing sleeve (37) and the toner supply roller (22) face each other.
The scraping action of the carrier and developer conveyed in a magnetic brush state based on the rotation in the direction of arrow (e) in 7), the development bias voltage (Vbυ) and the collection bias voltage (V
ss) (=Vrms+Vss).

In addition, in the toner supply area (B), in parallel with the toner supply operation, an operation is performed to collect excess toner on the developing sleeve (37) to the toner supply roller (22) by the electrostatic attraction force, and the developing sleeve (37) The toner concentration of the developer held above (the content ratio of toner to carrier) is maintained at a predetermined value.

Further, the toner collected by the toner supply roller (22) is conveyed in the direction of arrow (c), and the toner is transported to the toner outflow prevention plate (24).
) and are collected in the toner hopper (25).

The toner supplied to the surface of the developing sleeve (37) is taken in by the developer held in a magnetic brush state, and while being mixed with the developer, the developer flows based on the rotation of the developing sleeve (37). Refer to 4th reference] Along arrow (e)
During the conveyance process, the developer and toner are mixed microscopically based on the rotational force of the developing sleeve (37) and the magnetic force of the magnet (38), thereby improving their respective potentials.

The developer flowing on the developing sleeve (37) and being conveyed along the direction (3) reaches the part facing the developing sleeve (39), where the magnetic pole (S3) of the developing sleeve (37) and the developing sleeve (3
The developing sleeve (39) is attracted to the magnetic pole (N,) based on the lines of magnetic force generated between the developing sleeve (37) and the developing sleeve (39).
) to metastasize above.

The developer transferred to the developing sleeve (39) is conveyed in the direction of the arrow (f) along the flow (see Fig. 4) based on the rotation of the developing sleeve (39), and is transported between the magnetic poles (S, ) and (S, )
The developing sleeve (39) is separated from the outer periphery of the developing sleeve (39) at the non-magnetic pole portion (C) formed between the developing sleeve (39) and collected in the stirring tank (46).

Note that the developer conveyed from the direction of arrow (e) along the developing sleeve (37) is
39), the developer suddenly changes direction and heads in the direction of arrow (f), so that the developer is properly mixed and stirred here.

The developer separated from the developing sleeve (39) and collected is
Based on the rotation of the bucket roller (51) in the direction of arrow (g), the partition wall (49), (
50) Flow over. Then, the developer is placed in a bucket (54
) is scraped off by the scraping part (55) of the guide part (56
) flows into the bucket roller (51) in the direction of arrow (i), the flow direction is slightly changed by the inclined guide plate (59) and collides with the collision part (57), where it is mixed and agitated while flowing into the bucket roller (51). ) along the bucket roller (51)
The flow is divided into one flow toward the inside of the bucket roller (51) and one flow toward the outside of the bucket roller (51) from the opening (58) along the direction of arrow (k).

The developer heading inside the bucket roller (fifth eye) along the direction of arrow (D) flows into a pair of opposing buckets (54), (
Since the toner is further mixed and agitated while being circulated in the axial direction by the inclined guide plates (59) and (59) provided in the toner (54), uneven supply of toner and deviation of the developer are eliminated. The developer mixed and stirred in this way is charged to a predetermined charge and is discharged in the flow direction from the gap or opening (58) between the buckets (54) and (54) in the upper part of the figure. be done.

Also, along the arrow (k) direction, a bucket roller (51)
The developer flowing outside flows out from the opening (58) and is scraped off by the L-shaped portion (54a) on the outer surface of the bucket (54) along with the developer that was not scraped off, and is transported in the direction of the arrow (■). Otherwise, the liquid is scraped off by the scraping part (55) of the succeeding bucket (54), and flows in the same manner as described above.

The developer in the stirring tank (46) around the bucket roller (51) is scraped off by the L-shaped portion (54a) of the bucket (54) and released toward the developing sleeve (39) in the flow direction. be done.

On the other hand, at both ends of the developing sleeve (39), as shown in FIG.
The developer separated along the direction has poor fluidity due to disturbances in the magnetic field and the like.

However, as shown in FIG. 5, the developer in this area is scraped off in the direction of arrow <Q' by the scraping member (60) of the bucket (54) of the bucket roller (51), forming a wedge-shaped intake portion. (53b). This intake part (53b
) has an inclined surface that goes toward the inside of the bucket roller (51), so the developer here goes toward the inside of the bucket roller (51) along the direction of the arrow (m). As a result, the developer at both ends of the developing sleeve (39) is transferred to the stirring tank (
46), and there is no accumulation of developer, backflow to the lower developing sleeve (37), spillage, etc.

Furthermore, when the developer is compressed and the pressure increases within the intake portion (53b), a portion of the developer leaks in the direction of the arrow (n) through the escape hole (61).
There is no developer clogging from the to the intake portion (53b), and an increase in the torque of the drive shaft (52) is avoided.

Further, the developer scraped off by the scraping portion (55) or the scraping member (60) of the bucket (54) is likely to be disturbed by the outer peripheral edge of the bucket non-attached portion of the flange (53), (53). However, since the outer periphery of the non-bucket attachment part is thinner than the bucket attachment part, it flows from the outer periphery along the sloped part (53a) and flows to the bucket roller (55).
taken within. As a result, the flange (53), (
Even if the thickness of the bucket attachment part is thick, scraping by the scraping part (55) or the scraping member (60) is prevented within the range corresponding to the thickness of the outer peripheral edge of the bucket non-attached part in item 53). It is scraped off efficiently. Also,
Since the bucket attachment portions of the flanges (53) and (5B) are thick, the attachment strength will not decrease.

The developer mixed and stirred in the stirring tank (46) is transported toward the developing sleeve (39) along the flow (see Fig. 4), and a portion of the developer is opposed to the magnetic poles (S3) and (N3). It is held on the surface of the developing sleeve (39) again at the arrow (f).
direction, and the conveyance amount is regulated at the portion facing the height regulating plate (41).

The developer that has passed through the part facing the height regulating plate (41) is conveyed in the direction of the arrow (f) in the state of a magnetic brush, and is moved along the flow (see reference 4) to the photoreceptor drum (100) and the developing sleeve ( 37), the electrostatic latent image formed on the outer peripheral surface of the photoreceptor drum (100) is rubbed and visualized as a toner image.

The developer that has passed through the development area (D) is transferred to the development sleeve (3).
9), the magnetic pole (Sl) of the developing sleeve (39) and the magnetic pole (N, The magnetic pole (N
, ), and the developing sleeves (39) and (37)
It transfers to the developing sleeve (37) without entering the space between the developing sleeves (37).

The developer transferred to the surface of the developing sleeve (37) is conveyed in the direction of arrow (e) based on its rotation, and is transported to the phenomenon area (
In step E), the toner comes into contact with the electrostatic latent image on the photoreceptor drum (100) again, and toner is again supplied to the toner image developed in the development area (D). Therefore, toner is replenished even in the area where toner supply was insufficient in the phenomenon area (D), and density unevenness and white spots due to insufficient toner supply do not occur.

The development in the development areas (D) and (E) is performed using the development bias voltages (vb t) and (vb t) applied to the development sleeves (39) and (37) and the photoreceptor drum (100).
) and the surface potential.

The developer that has passed through the development area (E) is conveyed along the flow (see Figure 4) to the part facing the toner supply roller (22), where an amount of toner corresponding to the amount consumed by development is collected. Supplied.

The supplied toner is conveyed along the outer peripheral surfaces of the developing sleeves (37) and (39) as described above.

By repeatedly performing development as described above, the toner in the toner cartridge (15) is gradually consumed, and along with this, the toner hopper (25) and the path (28) are consumed.
) decreases, the toner empty detection device (30) rotates in the direction of arrow (i) to detect that the toner cartridge (15) should be replaced, that is, the toner empty state. Ru.

Then, by installing a new toner cartridge (15) containing sufficient toner, the toner empty state is resolved.

(2) Other Examples In the above description, the developing device (1) is equipped with two developing sleeves (37) and (39), but the present invention can also be applied to a developing device equipped with even more developing sleeves. is applicable.

Further, in the above embodiment, the developing sleeves (37), (39)
), the present invention is applied to a developing device that supplies toner into the flow of developer that is being conveyed on the surface of the sleeve. The present invention is also applicable to things.

Further, in the above embodiment, a case is shown in which a photoreceptor drum (+00) is used as an electrostatic latent image carrier. A device can be used.

(Effects of the Invention) As is clear from the above description, according to the present invention, the developer is scraped off by the scraping member at both ends of the developing sleeve and taken into the bucket roller. In addition, since the developer leaks from the escape hole, the torque of the drive device does not increase.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a developing device equipped with a bucket roller according to the present invention, FIG. 2 is a perspective view of the bucket roller according to the present invention, FIG. 3 is a perspective view of the bucket, and FIG. FIG. 5 is a sectional view showing the state of developer transport and agitation by the bucket at both ends of the bucket roller. FIG. 6 is a sectional view showing the state of developer transport on the developing sleeve. FIG. 7 is a partial perspective view and a sectional view of a developing device equipped with a conventional bucket roller. l...Developing device, 37.39...Developing sleeve, 46...Developer stirring tank, 51...Bucket roller, 54...Bucket, 60...Scaling member, 61... escape hole. Figure 2 Figure 3 Figure 4 Figure 7

Claims (1)

[Claims] (1) In the bucket roller of the developing device that takes in the developer collected from the developing sleeve, mixes it with the developer stored in the developer stirring tank, and supplies it to the developing sleeve, the developing sleeve of the bucket of the bucket roller A flexible scraping member whose tip contacts or is close to the wall surface of the stirring tank is provided protrudingly at a position facing both ends, and an escape hole is provided in the vicinity of the scraping member. Bucket roller of developing device.