JPS63146071A - Developing device - Google Patents

Abstract

PURPOSE:To prevent the surface of a developer carrying member from flawing and the tip edge part of a blade member from wearing, and to improve the durability of the titled device, by providing a rotary member for scraping down substantially once a residual carrying developer on the surface of the developer carrying member between the developer carrying member and a developer stirring member in a developer chamber. CONSTITUTION:A developer which passes through a developing part and carried on the surface of a developer carrying body 71, and returned and carried to a developer chamber 4 side is subjected to scraping action positively by a rotational force of a rotary member 14, in a process for passing through the position of the rotary member 14 positioned in the vicinity of the surface of the developer carrying body 71 in the developer chamber 71, and it is all scraped down successively from the surface of the developer carrying member 71. In this case, since the rotary member 14 does not come into contact with the developer carrying member surface 71, flawing of the developing member 71 surface caused by mutual rubbing of the developer carrying member 71 and the rotary member 14, and such a phenomenon as a filming adhesion of a toner to the member 71 surface, etc. are not generated over a long period of time. Also, it does not occur that the developer which has been scraped down successively from the developer carrying member 71 surface by the rotary member 14 becomes a holdup state in a part of the position of the rotary member 14.

Description

[Detailed Description of the Invention] A1 Object of the Invention [Industrial Application Field] The present invention provides a method for forming a latent image on a latent image carrier such as a photoreceptor or dielectric material by an appropriate image forming method in electrophotography, electrostatic recording, etc. The present invention relates to a developing device that develops a latent image using dry toner.

[Conventional technology]

Specifically, various structural type developing devices are known as the above-mentioned developing device, but in general, the developer (l-component type The developer is supplied with a developer (or two-component developer), carries the developer, conveys the carried developer to the surface of the PB image carrier, develops the latent image, and leaves the residual developer that has passed through the developing section. Many developing devices include a developer carrying member that carries the developer as it is and returns it to the developer chamber.

[Problem that the invention seeks to solve]

In the case of such a developing device, one of the requirements for consistently and stably performing high-quality image development without the occurrence of so-called ghost images or density unevenness is that the developer passes through the developing section and is carried on the developer carrying member. The developer transported back to the developer chamber is sequentially detached and removed from the surface of the developer carrying member, and well-stirred developing agent is re-supplied and carried on the surface of the developer carrying member from which the developer was removed. , the carried developer may be conveyed again to the surface of the 1 image carrier to develop the PF3 image.

Therefore, a developer scraping blade member is disposed in the developer chamber with its leading edge in contact with or very close to the surface of the developer supporting member, and the blade member returns the developer transported to the developer chamber and develops the developer. Some products are designed to be scraped off from the surface of the agent carrier. However, this configuration relies on (1) mutual sliding between the surface of the developer carrying member and the tip edge of the blade member. In practice, it lacks durability because it tends to cause scratches on the surface of the developer holding member, wear of the tip edge of the blade member, so-called filming of toner on the surface of the developer holding member, and the like.

(2) In addition, the developer scraped off from the surface of the developer carrying member by the blade member becomes a hindrance member and tends to stay in the blade member, causing re-mixing and agitation of the developer in the developer chamber. is difficult to perform smoothly.

The present invention does not have the above-mentioned problems (1) and (2), and therefore, high-quality image development can always be carried out stably over a long period of time. It is an object of the present invention to provide a developing device of this type that has high durability and reliability and is fully applicable to high-speed image forming devices.

1. Structure of the Invention [Means for Solving the Problems] The present invention provides a developer chamber having a built-in developer stirring member that receives a supply of agitated developer and supports the developer, and the carried developer. In a developing device comprising a developer carrying member which is conveyed to a side of a latent image holding body to develop a latent image, and which carries residual developer that has passed through a developing section as it is and conveys it back to a developer chamber side. , between the developer carrying member and the developer agitating member in the developer chamber, the remaining carried developer on the surface of the developer carrying member returned from the developing section in close proximity to the two members is substantially scraped once. The gist of the present invention is a developing device characterized by being provided with a rotating member for dropping.

[For production]

That is, the developer passed through the developing section, carried on the surface of the developer carrier, and transported back to the developer chamber side passes through the rotating member position located in the developer chamber close to the surface of the developer carrier. In the process, substantially all of the developer is successively scraped off from the surface of the developer carrying member by being actively scraped off by the rotational force of the rotating member. In this case, the rotating member is close to and facing the surface of the developer carrying member, but is not in contact with it, so the developing member surface may be scratched due to mutual sliding between the developer carrying member and the rotating member, and toner may not be filled onto the surface of the member. Phenomena such as ming adhesion do not actually occur over a long period of time.

Further, the developer that has been sequentially scraped off from the surface of the developer supporting member by the rotating member is moved to a portion opposite to the developer stirring member in the developer chamber adjacent to the rotating member due to the continuing rotational force of the rotating member. The developer is actively conveyed, and the developer is stirred and fluidized by the operation of the developer stirring member at the opposing part! It merges with the developer in the developer chamber E and is well mixed and agitated with each other, so that it does not stagnate in the area where the rotating member is located.

Then, the above-mentioned developer, which has passed through the facing portion of the rotating member and the developer stirring member and has been thoroughly mixed and agitated with each other, is replaced with new developer on the surface of the developer carrying member from which the carried developer has been scraped off by the rotating member. The cycle of being re-supplied as a material, carried on the surface of the member, and transported to the developing section is repeated and smoothly performed,
As a result, it is possible to stably develop a latent image with high image quality over a long period of time.

〔Example〕

The drawings show one embodiment of the developing device of the present invention.

In FIG. 1, A is a drum-shaped, belt-shaped, sheet-shaped electrophotographic photosensitive member, electrostatic recording dielectric material, etc. as a latent image holding body, which is driven to move in plane at a predetermined speed in the direction of the arrow, and is not shown. A latent image is formed by the image forming process equipment, and the latent image is developed as a visible image by the developing section B.

In the developing section 2tB, l is a developing container, and the interior thereof is divided into a storage chamber (toner hopper chamber) 3 for replenishing non-magnetic toner by a partition wall 2, and a developer chamber (toner hopper chamber) 3 containing a developer made of non-magnetic toner and magnetic particles. It is divided into a developer stirring chamber (4). Toner stored in the toner storage chamber 3 and developer chamber 4
The developer inside is omitted from the figure for convenience.

Reference numeral 71 denotes a non-magnetic developing sleeve as a developer carrying member disposed in the developer chamber 4, and the lower right side portion of the developing sleeve 7I is exposed to the outside through an opening provided in the developer chamber 4. , the developing device B is positioned and held by the support member so that the externally exposed surface of the developing sleeve 7□ faces the surface of the latent image holder A with a predetermined small gap. The opposing portion a between the latent image holder A and the developing sleeve 7I is a developing section.

72 is a multi-pole magnet roll inserted into the developing sleeve 71 and used as a magnetic field generating means. The roll in this example has 6 magnetic poles of N, -N3 degrees S1 to S3 on the circumferential surface, and N pole -5. This is a permanent magnet roll whose poles are alternately magnetized at predetermined intervals.

This magnet roll 72 is fixedly supported at both ends and does not rotate, and the outer developing sleeve 7□ is driven to rotate around the fixed roll 72 in the direction of the arrow at a predetermined circumferential speed.

Reference numerals 8 and 9 designate screw shafts serving as developer stirring/transporting means that are disposed above and below substantially parallel to the developing sleeve 7 in the developer chamber 4, and are each driven to rotate in the direction of the arrow.

10 is a developer circulation regulating member provided on the L side of the developing sleeve 7e in the developer chamber 4; 17 is a developer circulation regulating member provided between the screw shafts 8 and 9 on the circumferential surface of the developing sleeve 71; The circulation area designating members 11 and 13 are designed to prevent the stored developer from flowing and leaking toward the latent image holder A from the gap between the bottom surface of the developer chamber 4 and the bottom surface of the developing sleeve 7 plate. A magnetic member disposed on the bottom side, 12 is a developing sleeve 7
In order to regulate the layer thickness of the developer formed on the circumferential surface of the developing sleeve 71, a non-metallic material is disposed on the upper surface side of the developing sleeve 71 with its lower side facing the upper surface of the developing sleeve with a predetermined small diameter gap. It is a magnetic blade.

14 is arranged in the developer chamber 4 in the open position of the developing sleeve 71 and the lower screw shaft 9 as a developer stirring/conveying member, in close proximity to both members 71 and 9, respectively, and parallel to the sleeve 7□. It is a rotary member provided as a developer scraping member, and is rotationally driven in the direction of the arrow at the circumferential speed of the developing sleeve 7I or at an appropriate speed faster than that. The rotating member 14
is a non-magnetic metal or resin roller member, and its outer periphery scrapes off the compatible developer on the surface of the developing sleeve 71 as shown in FIG. Parallel protrusions 14a and grooves 14b are formed in the generatrix direction so that the agent can be held and conveyed evenly in the axial direction. The rotary member 14 has an angle of 0.5 to 1 at its closest point to the developing sleeve 7.
They are arranged close to each other so as to face each other with a gap of mm.

A sensor 15 detects the concentration of the developer (mixing ratio of toner and magnetic particles) in the developer chamber 4. Examples of the sensor 15 include a developer body change detection element, a piezoelectric element, and an inductance change detection element. , an antenna method using an alternating bias, etc. can be used.

The multi-pole magnet roll 7□ as a magnetism generating means
Regarding each magnetic pole, the N pole is located at a position 8, which serves as a developer application rod, and is substantially opposed to the non-magnetic blade 12, which serves as a developer layer thickness regulating member.

The N2 pole is a developing pole and is located at a position facing the developing section a, that is, the surface A of the latent image carrier. The S1 pole serves as a developer transport pole and is located in an open position between the N pole and the N2 pole. The S2 pole and the N3 pole serve as developer leak prevention rods, and are located at positions facing the aforementioned magnetic members 13 and 11 provided on the bottom surface of the developer storage section 4, respectively. The S3 pole serves as the developer transport pole and the N
It exists in the open position between the 1st pole and the N3 pole.

When the developing device is in operation, the developing sleeve 71 and screw shafts 8 and 9
, the rotating members 14 are each driven to rotate at a predetermined speed,
An alternating voltage is applied between the developing sleeve 7□ and the latent image holder A by a bias power supply S.

The movement of the developer in the developer chamber 4 on the cross section of the developer chamber is caused by the rotation of the developing sleeve 71, the rotation of the screw shafts 8 and 9, the rotation of the rotating member 14, the magnetic field of the magnet roll 72, and developer circulation regulation. Due to the presence of the member 10, the circulation area specifying member 17, the frictional force between the developing sleeve 7 and the developer, the gravity of the developer, etc., a cyclical flow motion as shown by the white arrow in FIG. 1 is achieved.

That is, the developer in the developer chamber 4 is generally well stirred and fluidized by the rotation of the upper and lower screw shafts 8 and 9 serving as developer stirring and conveying means. In this example device, the screw shaft 8
9 are rotated in the same direction as indicated by the arrows, but the screw blades of each screw shaft are oriented in opposite directions, so that the developer near the upper screw shaft 8 and the lower screw shaft 9 Neighboring developers are transported in opposite directions with respect to the longitudinal direction of the screw shaft.

The developer in the developer chamber 4 is sufficiently agitated in the longitudinal direction of the developing sleeve 7 by the agitation caused by the rotation of the upper and lower screw shafts 8 and 9, and at least the north screw shaft 8 and the lower screw shaft 9 are mixed. - The developer in the area surrounded by the rotating member 14 and the developing sleeve 71 has a substantially uniform mixing ratio of toner and magnetic particles in each longitudinal direction of the developing sleeve 71;
Also, the toner is in a state where sufficient tripo is given.

The developer is supplied to the surface of the developing sleeve 71.

As the developing sleeve 71 rotates, the developer flows through the magnetic pole S3 position in the direction of the developer circulation regulating member 1o, most of it flows in the direction of the upper screw shaft 8, and a part is carried on the surface of the developing sleeve 7 and flows into the member. The layer thickness is regulated in the process of passing through the lower surface side of LO and the lower edge position of the non-magnetic blade 12 serving as a two-layer thickness regulating member, and then conveyed to the developing section a by the subsequent rotation of the developing sleeve 71.

The member IO has the effect of imparting a sufficient tripo to the toner for the developer carried on the surface of the developing sleeve 71 passing through its lower surface, and also has the effect of imparting a sufficient tripo to the developer undulating in the direction of the upper screw shaft 8. This has the effect of increasing the developer conveying force of the upper screw shaft.

The developer that has flowed in the direction of the upper screw shaft 8 flows downward from the upper side of the screw shaft 8 to the side opposite to the developing sleeve 71, and a part of the developer flows between the member 17 and the upper screw shaft 8 within the guide of the member 17. It passes through the gap and heads towards the developing sleeve 71 side. The other part passes between the lower screw shaft 9 and the partition wall 2, and in the process of passing, the lower screw together with the toner that is sequentially replenished from the toner storage chamber 3 side to the developer chamber 4 side through the opening 34 of the partition wall 2. It flows to the lower side of the shaft 9, further passes between the lower screw shaft 9 and the rotating member 14, and circulates IM again toward the developing sleeve 71. The toner supplied to the developer chamber 4 side through the opening 1134 is transported in a flowing manner under the side screw shaft 9, and in the process of passing between the screw shaft 9 and the rotating member 14, it is mixed into the developer. All parts are stirred and mixed uniformly.

The member 17 not only regulates the developer circulation path as described above, but also serves to enhance the developer conveyance effect of the upper screw shaft 8.

On the other hand, the developing sleeve 7 passes through the non-magnetic blade 12 position.
, the developer carried on the surface and transported to the developing section a is affected by the electric field acting on the developing section a during the passage through the developing section a,
Due to the magnetic field action of the magnetic pole N2, the brush-shaped magnetic particles contained in the carrying developer layer on the side of the developing sleeve 7 are formed to be longer than the opposing gap length between the surface A of the latent image carrier and the developing sleeve 7.

Alternatively, the toner forms a latent image by being elongated by the electric field of the developing section a and rubbing against the surface of the latent image holder A, and by reciprocating between the sleeve 71 side and the latent image holder A side. The toner is transferred and adhered to the A side of the holder in accordance with the latent image pattern, and the latent image on the A side of the latent image holder is sequentially developed.

The remaining developer layer on the side of the developing sleeve 7 that has been subjected to development and has passed through the developing section a is held as it is on the surface of the sleeve 71 by the magnetic field of the magnetic poles S2 and N3 within the developer chamber 4 due to the subsequent rotation of the developing sleeve 7I. and transported back.

The above-mentioned developer carried by the developing sleeve 71 from the developing section a side and transported back into the developer chamber 4 passes through the close facing portion between the developing sleeve and the rotating member 14, and in the process,
Actively using the rotational force of the rotating member 14! - Substantially all of the surface of the developing sleeve 71 is sequentially scraped off by the scraping action. In this case, the rotating member 14 is close to and facing the surface of the developing sleeve 71, but is not in contact with it, so the developing sleeve 7 and the rotating member 14 are in phase with each other. In fact, phenomena such as scratches on the developing sleeve 71 due to rubbing and toner filming adhesion to the sleeve surface do not occur for a long period of time.

The developer that has been sequentially scraped off from the surface of the developing sleeve 71 by the rotating member 14 passes through the lower side of the rotating member 14 due to the continuous rotational force of the rotating member 14 without causing any stagnation. The developer flow is actively conveyed to the opposite part of the screw shaft 9, and merges with the circulating developer flow in the developer chamber 4, which is also conveyed to the opposite part through the lower side of the lower screw shaft 9, and mutually The mixture is well mixed and stirred and flows toward the developing sleeve 7I.

Then, the developer is re-supplied as new developer to the surface of the developing sleeve 7 from which the supported developer has been scraped off by the rotating member 14, and is carried on the sleeve surface.

The cycle of being transported to the developing section a again is repeated.

That is, the rotating member 14 effectively transfers the residual developer transported from the developing section a back to the developer chamber 4 from the developing sleeve 71 without causing any damage to the sleeve surface or 2) causing toner filming or the like. The action of scraping and removing.

(b) The action of actively conveying the scraped developer to the lower screw sleeve 9 side and stirring and mixing the old and new developer with each other at the closest point to the lower screw shaft.

C1 is a member that also has the function of transporting and supplying the mixed developer to the developing sleeve 7I as a new developer 8 The above-mentioned function of this rotating member 14 allows stable and long-term development of high image quality. can be executed over
A developing head is constructed that has high durability and reliability and is fully applicable to high-speed image forming apparatuses.

The refill storage unit 3 in this example device includes a first compartment 3 (first developer chamber) adjacent to the developer chamber 4, and a side opposite to the developer compartment 4 with the first compartment inside. 2nd compartment (2nd
It is divided into two chambers (hopper chamber) 32 via a partition wall 33.

Reference numeral 34 denotes a first toner supply window hole provided in the partition wall 2 between the developer chamber 4 and the first compartment 31, and 35 indicates a first toner replenishment window hole provided in the partition wall 33 between the first compartment 31 and the second compartment 32. Therefore, the second compartment 32 is the toner supply window hole of the first compartment 31.
i! through the second window hole 35. I! The first compartment 31 communicates with the developer storage section 4 through a first window hole 34.

36 and 37 are the first and second mesh members stretched over the first window hole 34 and the second window hole 35, and 41-42 are the mesh members stretched inside the first and second compartments 31 and 32. ? The first and second toner conveying members arranged are horizontally elongated rectangular frames, respectively.
Bearings are held to freely rotate around the central horizontal shafts 41a, 42&, and the central horizontal shafts 41a, 42 are supported by a drive system (not shown).
It is driven to rotate at a predetermined speed in the direction of the arrow centered at a.

2. Horizontal frame sides 41b, 41b, 42 of the two longitudinal sides of the first and second toner conveying members 41, 42 in the shape of a horizontally elongated frame body
b-42b has rigid strip plates 41c, 41c and 42cφ, respectively.
Rubber plates 41cl, 41d, 42d via 42c
・It is provided by gluing 42d.

: Every time the rubber blade 41d portion contacts and rubs the surface of the first mesh member 36 stretched over the first toner supply window hole 34 due to the rotation of the toner conveying member 41 at tS1,
m1 compartment 3 scooped by the rubber blade 41d part
1, some of the toner present in the mesh member 36,
The developer is sequentially replenished to the developer storage section 4 side through the first window hole 34 .

Further, due to the rotation of the second toner conveying member 42, the rubber blade 42d portion is attached to the second toner replenishing window hole 35.
Each time the toner comes in contact with the surface of the mesh member 37 and slides through it, a portion of the toner present in the second compartment 32 that is scooped up by the rubber blade 42d is transferred to the mesh member 37, the second
It is sequentially replenished to the first compartment 31 side through the window hole 35.

When the second compartment 32 runs out of toner, a predetermined amount of toner is replenished to the second compartment 32 using a toner container (toner cartridge).

In this way, the toner in the developer in the developer chamber 4 is consumed in developing the latent image, and the mixing ratio with the magnetic particles decreases over time.The degree of this decrease is detected by the sensor 15. The information is input to a control circuit (not shown), and when the degree of decrease reaches a predetermined allowable lower limit, the signal causes the first and second toner conveying members 41 and 42 inside the toner storage section 3 to be activated.
As a result, the toner in the toner storage section 3 is sequentially introduced into the developer chamber 4 and replenished.

The replenished toner is stored in the developer in the developer chamber 4.
As described above, this toner replenishment, which is imprinted into the image and mixed uniformly and quickly throughout the developer, increases the toner mixing ratio of the developer in the developer chamber 4 and reaches a predetermined allowable increase. When this is detected by the sensor 15, the rotational drive of the first and second toner conveying members 41 and 42 is stopped. As a result, the ratio d1 of the toner to the magnetic particles of the developer in the developer storage portion 4 is always kept substantially constant.

C. Effects of Udeaki According to the present invention, problems such as (1) and (2) of the prior art have been eliminated, and therefore, high-quality image development can be carried out stably over a long period of time. The intended purpose is well achieved if a developing device of this type is available which can be implemented.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a cross-sectional side view of a developing device, and FIGS. It is a diagram. A is the latent image holding member, B is the entire developing device, 7. 14 is a developing sleeve as a developer carrying member, 4 is a developer chamber, 8 and 9 are two screw shafts as a means for stirring and transporting the developer;
is the developer scraping rotating member.

Claims (1)

[Claims] (1) A developer chamber containing a built-in developer stirring member receives the supply of agitated developer, carries the developer, and conveys the carried developer to the surface of the latent image carrier to develop the latent image. In a developing device having a developer carrying member that carries residual developer that has passed through the developing section and returns it to the developer chamber side, the developer carrying member and the developer stirring member in the developer chamber are connected to each other. A developing device characterized in that a rotating member is disposed between the two members in close proximity to the two members to substantially once scrape off the remaining carried developer on the surface of the developer carrying member returned from the developing section.