JP2003149943A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device which can maintain high image quality at high speed for a long period of time, and decrease the frequency of the maintenance and inspection of an image forming apparatus and of which the increase in size is avoided. SOLUTION: The developing device is provided with: a plurality of rotatable developer carrier members which are spaced by prescribed intervals from a latent image carrier member carrying an electrostatic latent image and having a movable outer circumference, and carry and transport a developer on the surfaces; and substantially one developer housing member. The developing device is pressurized in the direction of the latent image carrier member. A plurality of portions of the developer housing member are joined by an elastic member, the plurality of portions are relative movable to each other within a fixed range in the direction of the latent image carrier member, and the developer is freely movable inside the developer housing member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for visualizing an electrostatic latent image on a latent image bearing member with a developer.

[0002]

2. Description of the Related Art In an image forming apparatus such as a US, a copying machine or a printer, as shown in FIG. 7, an electrostatic latent image is formed on the surface of a latent image carrying member 1 and a static image on the electrostatic carrying member 1 is formed. The electrostatic latent image is developed by the powder toner in the developing device 4, the image is transferred to the transfer material m, and then the image on the transfer material m is fixed by the fixing device 7.
The image is fixed and fixed.

In the recent rapid progress in computerization and networking, image forming apparatuses of the type that receive computer information via a network and output the information are rapidly becoming popular. The demand for higher image quality is becoming stronger day by day.

In the developing device used in such an image forming apparatus, as described in Japanese Patent Application Laid-Open No. 03-204084, a plurality of developer carrying members of the developing device are provided, so that the developer carrying member 41a. , 41b and the portion where the toner reciprocates between the latent image carrying member 1 (hereinafter referred to as the developing unit Z
The width Wdev in the circumferential direction of the latent image bearing member 1 (referred to as dev)
It is attempted to reduce the load per developer carrying member 1 by efficiently enlarging (FIG. 8).

The reason for "efficiently" is as follows.

That is, even if the number of the developer carrying members is 1, if the outer diameter of the developer carrying member is increased, the width Wdev is increased, but the developing device and the image forming apparatus including the developing device are upsized. Not only that, especially when the developer carrying member has a built-in permanent magnet, the mass of the device and the cost of the device increase, which is contrary to the request for space saving.

[0007]

However, in the image forming apparatus according to the above-mentioned prior art, in particular, the toner existing between the adjacent developer carrying members and the frictional force between the two developer carrying members and the inside of the toner. There is a problem that the temperature of the developing device rises due to the heat generated by the friction.

[0008] The temperature rise of the developing device causes deterioration and denaturation of the toner mainly composed of resin, leading not only to image deterioration such as a decrease in image density, fog, and vertical streaks, but in extreme cases,
The decrease in toner fluidity causes an increase in the driving torque of the movable member of the developing device, resulting in damage to the developing device and the image forming apparatus.

Further, this phenomenon becomes more remarkable as the outer peripheral movement speed (process speed) of the latent image carrying member becomes higher. This is because as the process speed becomes higher, the developer carrying member also needs to rotate at higher speed (about 600 mm / s).

Further, when the two adjacent developer carrying members are close to each other, the toner agglomerates generated on the one developer carrying member and the adhering foreign matter move to another normal developer carrying member. There was a problem that affected.

In order to avoid such a problem, a plurality of developing devices that use the same toner are spaced from each other to some extent and arranged in the circumferential direction of the developer carrying member. This leads to an increase in equipment cost.

The present invention has been made in view of the above problems, and an object thereof is to maintain high image quality at high speed for a long period of time, reduce the frequency of maintenance and inspection of an image forming apparatus, and increase the size thereof. It is to provide a developing device capable of avoiding the above.

[0013]

In order to achieve the above object, the present invention is arranged with a predetermined space between a latent image carrying member carrying an electrostatic latent image and having a movable outer periphery, and In a developing device provided with a plurality of rotatable developer carrying members for carrying and carrying the developer on the surface and substantially one developer containing member, wherein the developer containing member is pressurized in the direction of the latent image carrying member, The member has a plurality of parts coupled by an elastic member, and the plurality of parts are movable relative to each other within a certain range in the direction of the latent image carrying member, and the developer accommodating member. It is characterized in that the developer can move freely inside the member.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1> FIG. 2 is a sectional view of an essential part of an image forming apparatus equipped with a developing device according to an embodiment of the present invention. The image forming apparatus shown in FIG. φ
Process speed 660m using 108 a-Si drum
m / sec, continuous output speed 120 pages (A4) // min
This is a black and white digital copier.

The latent image carrying member 1 is uniformly charged to, for example, +450 V by the primary charging device 2, and then image exposure Ei is performed. The image exposure is performed with a laser beam having a wavelength of 680 nm modulated by the first image signal using the semiconductor laser 301 as a light source. The laser beam is polarized by a polygon mirror 302 that rotates at a constant number of rotations by a motor, is reflected by a folding mirror 304 via an imaging lens 303, and is then raster-scanned on the latent image holding member 1 to expose its exposed portion. A surface image is formed by attenuating the surface potential to + 50V, for example.

After that, development is performed, and the toner image is charged by the charging device 5, and the attraction between the latent image carrying member 1 and the toner is weakened so that transfer and separation are facilitated. afterwards,
The transfer separation charging device 6 transfers and separates the transfer material m to the direction of the arrow F, and sends it to the fixing device 7 to fix the toner image (FIG. 2).

The developing device 4 has a simple structure and employs a magnetic one-component developing system which requires no maintenance up to the output of 2 million times, which is the life of the developer carrying members 41a and 41b. The developing device 4 has one developer accommodating member 40 and two developer carrying members 41a and 41b that rotate in the direction of arrow A (FIG. 1). However, the developer accommodating member 40 is composed of two parts 40a and 40b, and most of the joints are connected to each other by the foamed polyurethane 49, so that the leakage of the toner is prevented (FIG. 3).

In FIG. 1, the boundary between the two portions 40a and 40b is a straight line S. As a result, the two parts 40a, 40
b can be moved relative to each other in the horizontal H direction, but cannot be moved in the vertical V direction and the longitudinal T direction (FIGS. 1 and 3).

Further, the developer accommodating member 4 has a second portion 40a,
Since the image forming apparatus is divided into 40b, the image forming apparatus has two pressure members 101a,
101b is provided.

By repeating the image formation, the developer accommodating member 4
When the toner in 0 is reduced, the piezoelectric element 44a outputs a signal to rotate the toner supply roller 46. By the rotation of the toner replenishing roller 46, the toner is replenished from the intermediate developer accommodating container 47 into the developing device through the slot provided with the toner replenishing roller 46.

Further, when the toner in the intermediate developer accommodating container 47 is reduced, the piezoelectric element 44b outputs a signal for rotating the agitating / conveying member driving motor of the toner cartridge (not shown), and the intermediate developer is still generated. If the toner in the container 47 is not replenished, it is determined that the toner cartridge is empty and a toner cartridge signal is issued.

The developer carrying members 41a and 41b are formed by blasting spherical glass particles onto a cylinder made of A6063 having a diameter of 32, which is a non-magnetic member, and then Nip plating and then Cr plating. Surface roughness of 4 μm Rz
And A contact-type surface roughness meter (Surfcoder (trademark) SE-3300 manufactured by Kosaka Laboratory Ltd.) was used to measure the surface roughness. The measurement condition is a cutoff value: 0.8 m
m, measurement length: 205 mm, feed speed: 0.1 mm
/ Sec, vertical magnification is 5000 times.

Fixed developer magnets 41a ', 41b' having 7 magnetic poles inside the developer carrying member 41a and 4 magnetic poles inside the developer carrying member 41b are provided. Since the gap Gab between the developer carrying members 41a and 41b is sufficiently large as 10 mm, the interaction of the permanent magnets 41a ′ and 41b ′ can be practically ignored, and the change over time of the thin toner layer on the developer carrying members 41a and 41b can be ignored. It can be reduced.

The developer carrying members 41a and 41b rotate at a speed 1.5 times that of the latent image carrying member 1 (990 mm / s). Toners near the developer carrying members 41a and 41b are regulated in layer thickness by the magnetic plate members 42a and 42b,
G12a = G12b = 240 μm.

Inside the developer accommodating member 40, there are four developer stirring and conveying members (43a, 43b, 43c, 43d).
It is arranged. The developer stirring / transporting member 43a transfers the toner discharged by the toner supply roller 46 to the developer stirring / transporting member 43c. Developer stirring / transporting member 43c
Has a maximum stirring diameter and causes a large flow of toner in the developer accommodating member 40.
The toner reciprocates between a and 40b. The developer stirring / conveying members 43a and 43b are respectively the developer carrying member 4
A developer is supplied to 1a and 41b.

A DC bias of +280 V and an amplitude of +300 V and an amplitude of 12 are applied to the developer carrying members 41a and 41b, respectively.
A rectangular wave of 00 V and a frequency of 2.7 kHz is applied as an AC bias.

Non-contact seal members 4C made of iron are provided near the both ends of the developer carrying member along the outer circumference of the developer carrying members 41a and 41b. The gap GC between the surface of the developer carrying member and the magnetic seal member is 400 ± 100 μm.

The toner has a positive charging property, and its weight average particle diameter is 8.0 μm. The particle size distribution of the toner can be measured by various methods. Here, a Coulter Counter TA-II (trademark) manufactured by Coulter Co., USA is used. A few mg of the sample was ultrasonically dispersed in a solution prepared by adding a few drops of a surfactant to a 1% aqueous solution of NaCl as an electrolytic solution, and
The size distribution of the 2-40 μm particles was counted through a 00 μm aperture.

As the binder resin for the toner, generally, a styrene-based styrene-acrylic copolymer, a styrene-butadiene copolymer, a phenol resin, a polyester or the like is used. In this embodiment, the styrene acrylic copolymer and the styrene butadiene copolymer are used in a ratio of 8: 2.

A charge control agent (usually internally added to the toner but can be externally added), nigrosine, a quaternary ammonium salt,
Triphenylmethane, imidazole and the like are used for positive toner. In the present embodiment, 2 parts of triphenylmethane (based on 100 resin components) are internally added.

In the case of the calorific fixing toner, a so-called wax is internally added and dispersed. As the wax, for example, polyethylene, polypropylene, polyester, paraffin or the like is used.

Since the toner has magnetism, iron oxide such as magnetite and ferrite is dispersed in the toner, but the amount thereof is generally about 60 to 100 parts.

As an external additive to the toner, silica for the purpose of imparting fluidity is mainly added in an amount of about 0.1 to 5 parts by weight. This silica is composed of toner particles and a developer carrying member 41a,
41b is interposed between the developer holding members 41a and 41b to reduce the wear of the developer holding members 41a and 41b and prevent the toners from aggregating to promote the replacement of the toners in contact with the toners in contact with the developer carrying members 41a and 41b. Play a role.

Further, for the toner, strontium titanate, cerium oxide, praseodymium oxide, lanthanum oxide,
Neodymium oxide may be added externally. These play a role of polishing and scraping the photosensitive drum 1, and as a result, an effect of polishing and removing the toner adhering to the photosensitive drum 1 in a film shape is obtained.

The average charge amount of the toner on the developer carrying member 41a at room temperature and room temperature is +5 to +10 μC / g, and the coating amount is 0.7 to 0.9 mg / cm ^2.
The average charge amount of the toner on 1b at room temperature and room temperature is +6 to +1
The coating amount is ² μC / g and the coating amount is 0.4 to 0.6 mg / cm ² .

In this embodiment, the toner excessively attached by the developer carrying member 41a upstream of the latent image carrying member 1 in the direction of rotation B is returned to the inside of the developing device by the downstream bank carrying member 41b, and Since the toners randomly attached to the image can be rearranged efficiently, the toner consumption can be reduced, and the image density is high, and uniform and thin lines can be reliably reproduced.

Specifically, when an original having an image ratio of 6% was copied and measured, it was found to be 50 to 60 mg / sheet (A4) in a developing device equipped with a developer carrying member according to US Pat. On the other hand, in the present embodiment, the amount is 39 mg / sheet (A4).

Further, the variation in the main scanning direction of the width W1 of the image obtained by copying the line original (FIG. 4) having a width of 200 μm and extending in the main scanning direction was 5 mm.

Here, in measuring the width W1, MacBet in the United States is used.
A Microdensitometer 2405 (trademark) manufactured by h company was used.

Table 1 shows the performance and the like of this embodiment. According to this, the superiority of the present embodiment is understood. Here, the image reflection density is RD-91 manufactured by MacBeth, Inc. in the United States.
4 (trademark) is a value obtained by measuring a copy image of a circular original having a maximum image density of 5 mm in diameter. The fogging was measured using TC-6DS (trademark) manufactured by Tokyo Denshoku Co., Ltd., and the reflectance on a copy image of an office planner SK (trademark) paper sold by Canon Sales Co., Ltd. This is the difference in reflectance.

<Second Embodiment> Next, a second embodiment of the present invention will be described. The same components as those in the first embodiment of the present invention are designated by the same reference numerals, and the description thereof will be omitted.

In the present embodiment, the developer carrying member 41
The difference from the first embodiment is that the gap Gab between a and 41b is 5 mm.

Since the gap Gab is small, the permanent magnet 41
Since the interaction of a'and 41b 'has begun to appear, unevenness of the developer layer on the developer carrying member occurs when the cumulative number of output times increases, and the uniformity of the output image is slightly inferior.

Table 1 shows the performance of this embodiment. According to this, the superiority of the present embodiment can be understood as compared with the conventional technique.

<Third Embodiment> Next, a third embodiment of the present invention will be described. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the present embodiment, the developing device 4 includes one developing container 40 and three developer carrying members 41a, 41b, 4
1 c, the diameter of the developer carrying member is 16 mm, and the rotation speed is 792 mm / s (FIG. 5).

The developing container 40 includes three parts 40a, 40.
b, 40c, and most of the joints are connected to each other by the foamed polyurethane 49.
Is the same as.

In FIG. 5, three parts 40a, 40b,
The boundary of 40c is the straight lines S1 and S2.

Further, the developer accommodating member 4 has three portions 40a,
Since the image forming apparatus is divided into 40b and 40c,
Three pressing members 1 for pressing these toward the latent image carrying member
01a, 101b, 101c are provided.

A gap G between the developer carrying members 41a and 41b
The gap Gbc between the ab and the developer carrying members 41b, 41c is 10 mm, and the developer carrying members 41a, 41b, 4
A fixed permanent magnet having 4 magnetic poles is provided inside 1c.

Developer carrying members 41a, 41b, 41c
Is 1.2 times as fast as the latent image carrying member 1 in the direction of arrow A (7
It rotates at 92 mm / s). Developer carrying members 41a, 4
The toner in the vicinity of 1b and 41c is the magnetic plate member 4 respectively.
The layer thickness is regulated by 3a, 43b, 43c, G3 = 240
μm.

Inside the developer accommodating member 40, five developer agitating / conveying members (43a, 43b, 43c, 43d, 43d,
43e) is provided. Developer stirring / transporting member 43d
Is composed of a combination of 1 cylinder and 8 blades, and transfers the toner discharged by the toner replenishing roller 46 to the developer stirring and conveying members 43a, 43b, 43c. The developer stirring / conveying members 43a, 43b, 43c supply the developer to the developer carrying members 41a, 41b, 41c, respectively.

A DC bias of + 320V and an amplitude of 1300V are applied to the developer carrying members 41a, 41b and 41c.
A rectangular wave bias with a frequency of 2.4 kHz is applied.

The average charge amount of the toner on the developer carrying members 41a, 41b, 41c at room temperature and normal humidity is +6 to +, respectively.
10 μC / g, +7 to +94 C / g, +8 to +10 μC
/ G, coating amount is 38 to 45 mg / cm ² , 34 respectively
~40mg / cm ^2, a 29~35mg / cm ^2.

When a toner consumption rate was measured by copying a document with an image ratio of 6%, it was found that the value was 50 to 60 mg / sheet (A4) in a developing device equipped with a developer carrying member according to the prior art. In this embodiment, the amount is 35 mg / sheet (A4).

Further, the variation in the main scanning direction of the width W1 of the image obtained by copying a line original having a width of 200 um and extending in the main scanning direction and having a length of 5 mm was 9.5 um.

Table 1 shows the performance and the like of this embodiment. According to this, it is understood that the durability is excellent and the maintenance cost is reduced although the cost is increased due to the complexity of the developing device.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the present embodiment, the developing device 4 has a complicated structure and requires regular maintenance, but employs a two-component developing system which provides high image quality. The toner and carrier constituting the developer will be described later.

The developer-carrying members 41a and 41b are SUS316 cylinders of φ20 which are non-magnetic members and are blasted with amorphous alumina particles, and have surface roughnesses of 10 μmRz and 8 μmRz, respectively.

The developer carrying members 41a and 41b rotate at a speed 1.6 times faster than the latent image carrying member 1 (1056 mm / s). The layer thickness of the toner in the vicinity of the developer carrying member 41 is regulated by the magnetic plate member 43, and G3 = 700 μm.

To the developer carrying members 41a and 41b, a DC bias of 300 V and a rectangular wave bias having an amplitude of 2000 V, a rest frequency of 1.55 kHz and a vibration frequency of 7 kHz are applied.

The gap GC between the surface of the developer carrying member and the magnetic seal member is 1000 ± 100 μm.

The average particle size of the carrier is preferably 30 to 56 μm. When the average particle diameter is 20 μm or less, the image density is lowered due to excessive charging of the toner and carrier adhesion to the latent image holding member is increased, and when the average particle diameter is 60 μm or more, fine line reproducibility of copying is deteriorated.

The saturation magnetization of the carrier is 75 emu / g (3
(For an applied magnetic field of 000 Oe), during development, the brush-like spikes formed by the carrier and toner that face the electrostatic latent image on the latent image bearing member are tightly tightened, and the gradation And reproduction of halftones deteriorate. Again 5
If it is 5 emu / g or less, it becomes difficult to hold the toner and the carrier on the developer carrying member, and there is a drawback that fog and toner scattering are deteriorated.

Further, if the residual magnetization and coercive force of the carrier are too high, the conveyance of the developer in the developing device is deteriorated, and image blurring and uneven density in a solid image are likely to occur. , Coercive force of 5 emu / g or less,
It should be 6.0 Oe or less (for an applied magnetic field of 3000 Oe).

As the binder resin applied to the toner, polyester, polyurethane, polyamide, epoxy resin,
Polyvinyl butyral, polyamide, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. alone or Can be mixed and used.

Further, with respect to the developer in which the above toner is used, a charge control agent such as colloidal silica and a fluidity modifier are contained in an amount of 0.1 to 5% by weight (preferably 0.1% by weight).
1 to 2% by weight) is preferably added.

As the carrier used in the present embodiment, surface-oxidized or non-oxidized metals such as iron, nickel, copper, zinc, cobalt, manganese, chromium, rare earths and their alloys or oxides and ferrites are used. Yes, and preferably ferrites sent from the metals zinc, copper, nickel, cobalt can be used.

It is also possible to coat the surface of the carrier with a resin or the like. As the method, any conventionally known method such as a method of dissolving or suspending a coating material such as a resin in a solvent and applying the coating material to adhere it to a carrier, a method of simply mixing with a powder, or the like can be applied.

As the substance adhered to the carrier surface, polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin,
Polyester resin, metal complex of di-t-butylsalicylic acid, styrene resin, acrylic resin, polyamide, polyvinyl butyral, nigrosine, amino acrylate resin, basic dye and its lake, silica fine powder, alumina fine powder, etc. alone or It is appropriate to use a plurality of.

The treatment amount of the above-mentioned compound may be appropriately determined so that the carrier satisfies the above-mentioned conditions, but generally, the total amount is preferably 0.5 to 20% by weight with respect to the carrier.

In a particularly preferred embodiment that can be used in the present embodiment, Cu-Zn-Fe ternary ferrite is used, the surface of which is a combination of a resin such as a chute resin and a styrene resin, for example, 70% of polyvinylidene fluoride and styrene-methylmethacrylate resin, polytetrafluoroethylene and styrene-methylmethacrylate resin, fluorine-based copolymer and styrene-based copolymer, etc.
It is a mixture having a ratio of 30 to 30:70, and is 0.1
One that is a coated ferrite carrier coated with ˜1% by weight.

As the fluorine-based copolymer, a vinylene fluoride-tetrafluoroethylene copolymer (10: 90-
90:10), and the styrene-based copolymer is styrene-2-ethylhexyl acrylate (20:80).
-80: 20), styrene-2-ethylhexyl acrylate-methacrylic acid (20-60: 5-30: 30-10-5)
0) is exemplified.

The average charge amount of the toner on the developer carrying members 41a and 41b at room temperature and normal humidity is -25 to -40 μC / g,
The coating amount is 40 to 50 mg / cm ² .

By repeating the image formation, the developer accommodating member 4
When the toner in 0 decreases and the toner concentration falls below 4%,
The toner concentration detecting element 43 ′ is the toner replenishing screw 4
Send a signal to rotate 6 '. The toner is supplied from the intermediate developer container 47 into the developing device by the rotation of the toner supply screw 46 '.

Inside the developer accommodating member 40, there are four developer stirring and conveying members (43a, 43b, 43c, 43d).
It is arranged. The developer stirring / conveying member 43a is composed of a combination of 1 cylinder and 8 blades, and the toner conveying member 4
The toner discharged by No. 5 is transferred to the developer carrying member 41a and the developer stirring and conveying member 43b. The developer stirring / transporting member 43b supplies the developer to the developer carrying member 41b.

Developer stirring / transporting members 43b, 43c, 43
Reference numeral d denotes a screw, which conveys the developer in a direction parallel to the rotation axis of the developer stirring and conveying member. Reference numeral 48 is a toner concentration detecting member.

The toner conveying member 45 conveys the toner discharged from a toner hopper (not shown) arranged on the front side of the developing device, and transfers it to the developer stirring and conveying member 43c.

When a toner consumption rate was measured by copying an original with an image ratio of 6%, it was 90 to 100 mg / sheet (A4) in the developing device equipped with the one developer carrying member according to the prior art. In this embodiment, 80 mg / sheet (A4)
Became.

Further, the variation in the main scanning direction of the width W1 of the image obtained by copying the line original having the width of 200 um and extending in the main scanning direction and having the length of 5 mm was 5.9 um.

<Fifth Embodiment> Next, a fifth embodiment of the present invention will be described. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The image sensing device according to this embodiment has a process speed of 393 mm / s and a continuous output speed of 72 pages (A4).
/ Min black and white digital copier. The rotation speed of the developer carrying member is 590 mm / s. The impression that the productivity of image output is low is hard to wipe away, but the burden on the image forming apparatus is light and the durability is improved accordingly.

Although the embodiments of the present invention have been described above, the prior art form N is the same as the embodiment N
It means that the developer accommodating member does not consist of a plurality of parts but completely constitutes one unit. That is, the relative positions of the plurality of developer carrying members are unchanged.

Further, Embodiment 1N of the US Pat. No. 6,058,058 means that the developer accommodating member in Embodiment 1 is composed of a plurality of completely independent parts. That is, the toner does not move between the plurality of developer accommodating members.

The technical scope of the present invention is not limited to the above embodiments. That is, the diameter, outer peripheral moving speed, surface treatment, and material of the developer carrying member, the size of the gap between the two developer carrying members, the distance between the developer carrying member and the latent image carrying member, and the latent image carrying member. The shape and peripheral movement speed, the prescription of developer, the particle size, the shape of the developer accommodating member, the position, the number, and the rotating direction of the developer stirring and conveying member are specified in the image forming apparatus specifications (output speed, image quality level required by the user. Etc.) can select the most suitable one.

As the plate-shaped member, a method of contacting the developer carrying member, a method of rotating not only the developer carrying member but also the magnet contained in the developer carrying member, etc., in other words,
All modifications that are considered small modifications in view of the spirit of the invention are within the scope of the invention.

[0089]

As is apparent from the above description, according to the present invention, the electrostatic latent image is carried and the outer periphery of the latent image carrying member is movable at a predetermined interval.
In a developing device provided with a plurality of rotatable developer carrying members for carrying and carrying the developer on the surface and substantially one developer containing member, wherein the developer containing member is pressurized in the direction of the latent image carrying member, The member has a plurality of portions joined by an elastic member, and the plurality of portions are movable relative to each other within a certain range in the latent image bearing member direction,
In addition, since the developer can freely move inside the developer accommodating member, high image quality can be maintained at high speed for a long time, maintenance and inspection frequency of the image forming apparatus can be reduced, and size increase can be avoided. The effect that can be obtained is obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a developing device according to the present invention.

FIG. 2 is a cross-sectional view of a main part of the image forming apparatus.

FIG. 3 is a perspective view of a developer accommodating member.

FIG. 4 is an explanatory diagram of a line image.

FIG. 5 is a sectional view of a developing device.

FIG. 6 is a cross-sectional view of a developing device.

FIG. 7 is a sectional view of a main part of a conventional image forming apparatus.

FIG. 8 is a sectional view of a conventional developing device.

[Explanation of symbols]

1 Latent image bearing member 4 Developing device 40 developer accommodating member 41 developer carrying member 49 Elastic member

[Table 1]

[Table 2]

Claims (6)

[Claims] 1. A plurality of rotatable developing devices, each of which is arranged at a predetermined distance from a latent image carrying member which carries an electrostatic latent image and whose outer periphery is movable, and which carries and conveys a developer on the surface thereof. In a developing device comprising a developer carrying member and substantially one developer containing member, wherein the developing device is pressurized in the direction of the latent image carrying member, the developer containing member has a plurality of parts joined by an elastic member. The plurality of parts are movable relative to each other within a certain range in the latent image carrying member direction, and the developer is freely movable inside the developer accommodating member. Characteristic developing device. 2. The developing device according to claim 1, wherein the predetermined range is 1 mm or less. 3. The developing device according to claim 1, wherein the number of the developer carrying members is two. 4. The gap between the closest parts of adjacent developer carrying members is 10 mm or more.
The developing device according to any one of 1. 5. The developing device according to claim 1, wherein the developer does not contain carrier particles. 6. The outer peripheral movement speed of the developer carrying member is
It is 600 mm / s or more, It is characterized by the above-mentioned.
4. The developing device according to any one of 4.