JP2590930B2 - Developing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for an electrostatic latent image used in an electrophotographic apparatus or the like, and more particularly, to a method in which a developer supplied to a developer carrying member is supplied to a predetermined thickness by a layer forming member. The present invention relates to a non-magnetic one-component developing device which regulates the electrostatic latent image to a visible layer by transporting the thin layer to a photosensitive member.

2. Description of the Related Art An example of a conventional electrophotographic copying machine will be described with reference to a schematic configuration diagram of FIG.

The electrostatic latent image carrier 10, which is a charge acceptor having a photoconductor layer formed on an aluminum substrate, has a drum shape. First, before image information is irradiated, the surface thereof is uniformly charged by a charging device 33. A document table 23 on which a document 22 to be copied is placed is provided above the light source 24.A light source 24 for irradiating the document 22 and a document An optical system 21 for guiding the reflected light from the electrostatic latent image holding member 10 to the electrostatic latent image holding member 10 is provided.

Further, after the electrostatic latent image formed on the surface of the electrostatic latent image holding member 10 in the exposure step is converted into a toner image developed by a developing device 25 installed around the electrostatic latent image holding member 10, Then, the toner image reaches the transfer device 26 and is transferred to the sheet 28 fed from the sheet feeding device 27.

The paper 28 onto which the toner image has been transferred is discharged by the peeling charging device 29 and peeled from the electrostatic latent image holding member 10 to fix the toner image.
30 to the toner image on the paper 28 by the fixing device 30.
Is established.

On the other hand, the untransferred toner remaining on the surface of the electrostatic latent image holding member 10 after the transfer process is de-charged by the pre-cleaning corotron 31 and then cleaned by the cleaning device 32.
Removed from 10 surfaces. In such a conventional electrophotographic copying machine, as a dry developing device for developing an electrostatic latent image formed on an electrostatic latent image carrier, a two-component developer including a toner and a carrier is conventionally used, A two-component developer has been developed and put to practical use, in which toner is charged by frictional charging with a carrier and the charged toner is electrostatically attracted to an electrostatic latent image.

However, when such a two-component developer is used for a long period of time, the developer deteriorates and fog occurs in the background portion of the copy image, so that the developer (carrier) must be periodically replaced.

Recently, a one-component developing method using a one-component developer composed of only a toner has been proposed from the viewpoint of preventing deterioration of the developer.

As shown in a schematic side sectional view of FIG. 4, the developing device using the one-component developer supplies the developer in the hopper 14 having an open top to the developer carrier 1 by the supply roll 3 and The electrostatic latent image on the electrostatic latent image holder 10 is developed by the carrier 1. The hopper 14 has a sufficient capacity to secure a sufficient amount of the developer and supply the developer by using the natural fall. It has a large and elongated shape.

For this reason, the above-mentioned developing device is difficult to use in a small-sized, particularly thin-type copying machine or the like, and the replenishment of the developer must be appropriately performed, so that there is an inconvenience that labor and time are required.

As a method for solving such inconvenience, as shown in FIG. 5, the developer is supplied from the horizontal side of the developing unit 9 by communicating with the opening behind the developing unit 9 in which the developer carrier 1 is accommodated. A developing device having a developer storage section 5 has been proposed (Japanese Patent Application No. 61-12175). According to this method, the height of the entire developing device can be greatly reduced, and it can be easily installed in a small and thin copier. Further, since the developer can be replenished from the side of the storage section, the developer replenishment operation can be performed efficiently in a short time.

In the developing device configured to supply the developer from the horizontal direction in the above configuration, the bottom of the developing unit 9 is rotated by the rotation of the developer delivery member 6.
In order to feed and fill the gap between the developer 9a and the supply member 3, and to attach the developer to the developer carrier 1, the gap is set to 0.
It must be as narrow as about 2 to 2 mm. For this reason, the developer 4 often accumulates on the gap, that is, on the wall surface of the bottom portion 9a of the developing unit 9, so that a sufficient amount of the developer 4 cannot be sent to the developer carrier 1.

As described above, a sufficient amount of the developer 4
Is not sent, a uniform solid black image cannot be obtained when a large area solid black image is copied.

Further, the rotation of the developer delivery member 6 causes the developer 4 to be frictionally charged with the inner wall of the storage portion in the developer storage portion 5 to cause aggregation of the developer and to easily accumulate in the gap, thereby leading to the above problem. Things often happened.

Further, even when the developer delivery member 6 rotates, the developer 4 in the developer storage unit 5 is not sufficiently fed to the developer supply member 3 and the gap between the supply member 3 and the bottom 9a, so that a wide area solid black image is formed. Has a drawback that a uniform solid black image cannot be obtained.

In view of the above, the present invention is directed to developing such that a sufficient amount of the developer 4 can always be sent to the developer carrier 1 so that the developer is not deposited in the gap between the bottom 9a of the developing unit and the developer supply material 3. It is intended to provide a device.

Means and Action for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, (1) the gap between the bottom 9a of the developing unit 9 and the developer supply member 3; In order to prevent the accumulation of the developer in the developing unit, and to prevent the aggregation of the developer due to the frictional charging between the inner wall of the developer storing unit 5 and the developer 4, the wall material forming the gap at the bottom 9a of the developing unit and the developing unit The inner wall material of the developer reservoir is made of a material having the same charge polarity as that of the developer, and (2) an opening communicating between the developer 9 and the developer reservoir 5
The lower position 8 of 11 is set above the position of the uppermost part 3h of the developer supply member so that the developer 4 fed by the rotation of the developer delivery member 6 is smoothly carried to the developer supply member 3. Thus, the present invention has been completed.

That is, as shown in FIG. 1, the developing device of the present invention includes a developer storage unit 5 communicating with an opening 11 behind a developing unit 9 provided with a developer carrier 1 and a developer supply member 3, The developer 4 is supplied from the storage unit 5 to the developing unit 9 by the rotation of the developer delivery member 6 in the storage unit 5, and is developed to the developer carrier 1 through the gap between the bottom 9 a of the developing unit and the developer supply member 3. A developer layer having a predetermined thickness and a charge is formed on the developer carrying member 1 by the regulating member 2 while supplying the developer 4, and the developer layer is applied to the electrostatic latent image of the electrostatic latent image holding member 10. In the developing device 12 which is conveyed and visualized, the inner wall material of the developer storage section 5 and the wall surface material forming the gap at the bottom 9a of the developing section 9 are made of a material having the same charge polarity as the charge polarity of the developer 4. The position 8 below the opening 11 is the uppermost position 3 of the developer supply member 3. It is characterized by being set above h.

In the developing device of the present invention, as shown in FIG. 2, a position 8a above the opening 11 that connects the developing section 9 and the developer storage section 5 is provided.
Is set closer to the developer supply member side than the lower position 8, and at the tip of the developer delivery member 6,
By providing the blade member 7 having an angle (θ) of 5 to 45 ° with respect to the horizontal direction m when approaching the position 8 below the opening 11, the developer 4 is supplied more smoothly. .

Embodiment With the configuration shown in FIG. 1, the housing 13 of the developing device 12
A cylindrical developer storage section 5 and a developing member storage section (development section) 9 are horizontally communicated with each other through an opening 11 by an ABS resin material.

The developer storage section 5 has a cylindrical shape and the developer 4 has 10
A cartridge 15 having an inner wall material filled with 0 to 500 g and made of a material having the same polarity as the charging polarity of the developer 4 is provided so as to be freely inserted and pulled out, and a blade member 7 having a surface width of 0.5 to 30 mm from the tip is provided. The developer 4 passes through the opening 11 through the slit opening 11a of the cartridge having an opening width of 5 to 300 mm by rotating the developer feeding member 6 provided at an angle of θ = 5 to 45 ° at a speed of 5 to 30 rpm. And sends it to the developing section 9.

The position of the lower portion 8 of the opening 11 is higher than the uppermost position 3h of the developer supply member 3, and the position 8a of the upper portion of the opening 11 is set closer to the developer supply member 3 than the position of the lower portion 8. .

In the developing section 9, the developer carrier 1 and the developer supply member 3 are rotatably disposed while being pressed against each other, and the regulating member 2 is pressed against the developer carrier 1 so as to be in a predetermined state. A developer layer having a positive charge with a thickness is formed,
The developer layer is conveyed to the electrostatic latent image on the electrostatic latent image holding member 10 and is electrostatically attracted and visualized.

The developer carrier 1 is a SUS shaft having a diameter of 13 mm, that is, a phenolic pipe 1b containing carbon and glass fibers having a thickness of 1 mm, a specific resistance of 1 × 10 ¹⁰ Ωcm, and a relative dielectric constant of 3.0 on a developing electrode 1a ( The coating material is a roll having an outer diameter of 15 mm in which the coating layer is conductively bonded.
A foam 3b is wound on 3a, and a coating layer 3c is formed on the surface. The surface has irregularities.

The regulating member 2 is SUS 304, CSP 3 / 4H, 0.1mm thick spring material
Silicone rubber (thickness: 1 mm) 2b containing 1% by weight of vanadium pentoxide is bonded to 2a with a width of 10 mm, and is set so as to be pressed against the surface of the developer carrier 1 at a pressure of 50 to 300 g / cm. It is.

A DC voltage of -200 is applied to the shaft 1a of the developer carrier 1.
Frequency 1~10KHz superimposed the ~-400V, V _pp is 400~4500V
High-frequency alternating voltage is applied to the electrostatic latent image carrier
A peripheral electric field is formed on the electrostatic latent image on 10 to move the developer layer to perform development.

The peripheral speed of the developer carrier 1 is 1.0 to 2.5 times the peripheral speed of the electrostatic latent image carrier 1, and in this embodiment, the developer carrier 1 rotates at a speed of 150 mm / sec.

The bottom 9a of the developing section facing the developer supply member 3 is formed in an arc shape to form a gap of 0.5 to 2 mm with the developer supply member 3, and the wall surface 9b has the same polarity as the charging polarity of the developer 4. Made of material having

Thus, the developer 4 sent out by the rotation of the developer delivery member 6 and dropped onto the developer supply member 3 from the opening 11 is compressed in the gap between the wall surface 9b and the concave portion on the surface of the developer supply member 3. The developer layer is embedded and sent to the regulating member 2 by the rotation of the developer carrier 1 to apply a positive charge to the developer 4 by triboelectric charging, and at the same time, a developer layer having a uniform thickness of the developer 4 on the developer carrier 1 Is formed (0.5 to 0.8 mg / cm ² ), sent to an electrostatic latent image, electrostatically attracted and developed into a visible image.

The developer 4 not used in this development is the developer carrier 1
With the rotation of, the lower portion 17a of the developing section is returned from between the lower seal member 17 and the developer carrier 1.

The lower seal member 17 is formed of a plastic sheet of 30 to 200 μm, and is pressed against the developer carrier 1 by the elasticity of the plastic sheet itself as shown in the figure, and a lower baffle 18 is provided in front of the lower seal member 17. The developer 4 is prevented from spilling out of the developing device 12.

Further, the developer 4 rubs against the wall surface 9b and the inner wall material of the cartridge when the developer feed member 6 rotates and passes through the gap, and is frictionally charged, but the constituent material of the wall surface 9b and the inner wall material of the cartridge is Since the material having the same polarity as the charge polarity of the developer 4, that is, the material having the above-described frictional charge polarity of the developer of zero or the opposite polarity to the charge polarity of the electrostatic latent image, the developer 4 is provided on the wall surface 9b. A sufficient amount of the developer 4 can be reliably sent to the developer carrier 1 without being electrostatically attracted and without being aggregated on the inner wall surface of the cartridge.

As a specific example, when the components of the inner wall material and the wall surface 9b of the cartridge are made of a negative Teflon material, and the developer 4 used is a negative developer containing a metal-containing dye, a wide area solid black uniform copy is obtained. An image was obtained.

In addition, even when a negative electrode material such as an ABS resin, an AS resin, a vinyl chloride resin, a polyolefin resin, or a polyester resin was used instead of the Teflon material, a solid black copy image having a uniform large area was obtained as described above.

As a comparative example, a test was conducted with the polyamide resin having a positive polarity changed to a Teflon material, and only a non-uniform solid black copy image quality was obtained.

As another specific example, the component material of the cartridge inner wall material and the wall surface 9b is made of a positive polyimide material, and the developer 4
Was used as a positive developer containing a quaternary ammonium salt, and a wide area, solid black uniform copy image was obtained.

Even if the inner wall material and the wall surface 9b of the cartridge are formed of a positive molding material such as a polyamide resin, a polyurethane resin, a melamine resin, or a polyurea resin in place of the polyimide agent, a uniform wide area solid black copy as described above. An image was obtained.

As a comparative example, a test similar to that described above was performed using a Teflon material having a negative polarity as a constituent material of the cartridge inner wall material and the wall surface 9b, and only a non-uniform solid black copy image quality was obtained.

Effects of the Invention In the non-magnetic one-component developing device of the present invention, the bottom 9a of the developing section
When the developer 4 passes through the gap between the developer supply member 3 and when the developer rubs against the inner wall of the developer storage portion (the inner wall of the cartridge), the developer is prevented from being triboelectrically charged and electrostatically attracted to the wall surface. As a result, the developer 4 does not accumulate in the gaps, and the developer aggregates do not occur in the developer storage section 5.
Since a sufficient amount of developer can be always obtained, a wide area solid black copy image can be obtained uniformly.

Further, since the position of the lower portion 8 of the opening 11 in the developing machine is higher than the uppermost portion 3h of the developer supply member 3, a sufficient amount of the developer 4 can be sent to the developer supply member 3.

Further, the position of the upper portion 8a of the opening 11 is closer to the developer supply member 3 side than the lower position 8, and the angle?
Can be smoothly fed from the storage section 5 onto the developer supply member 3, so that even when continuous black solid copy is performed, uniform copy image quality can always be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the structure of the developing device of the present invention, and FIG.
FIG. 1 is an explanatory view of the positional relationship between a blade member and an opening of a developer delivery member of the apparatus of FIG. 1, FIG. 3 is a schematic view of an example of an electrophotographic copying machine, and FIG. 4 is a schematic view of a conventional developing apparatus. FIG. 5 is a schematic view of a conventional developing device provided with a developer storage section in a horizontal direction. Symbols in the drawing: 1 ... developer carrier; 1a ... roll core; 1b ... conductive layer; 2
... Regulatory member; 2a ... Spring material; 2b ... Elastic body; 3 ... Developer supply member; 3a ... Rotary shaft; 3b ... Elastic roll; 3c ... Surface layer; 4 ... Developer; ... developer storage section; 6 developer delivery member; 6a rotating shaft; 7 blade member; 8 lower end of opening; 8a upper end of opening; 9 developing section; ... Developing unit bottom; 9b Bottom wall surface; 10 Electrostatic latent image holder; 11 Opening; 11a Cartridge slit; 12 Developing device;
…… Housing; 14 …… Hopper; 15 …… Cartridge; 1
7 Seal member; 18 Lower baffle; 21 Optical system; 22
…… Original; 23 …… Original table; 24 …… Light source; 25 …… Developer; 26…
... Transfer unit; 27 ... Paper feeding device; 28 ... Paper; 29 ... Charging device for peeling; 30 ... Fixing device; 31 ... Precleaning corotron; 32 ... Cleaning device; 33 ... Charging device.

Claims (4)

(57) [Claims] An image forming apparatus includes a developer storage unit communicating with an opening behind a developing unit provided with a developer carrier and a developer supply member. The developer is supplied from the storage unit by rotation of a developer delivery member in the storage unit. The developer is supplied to the developing unit, the developer is supplied to the developer carrier through a gap between the bottom of the developing unit and the developer supplying member, and the developer layer having a predetermined thickness and a predetermined thickness is formed on the developer carrier by the regulating member. In a non-magnetic one-component developing device that transports and visualizes the developer layer on an electrostatic latent image on an electrostatic latent image holding member, the developer layer includes an inner wall material of the developer storage unit and the bottom of a developing unit. The wall material forming the gap is made of a material having the same charge polarity as the charge polarity of the developer, and the lower position of the opening is set to be higher than the uppermost position of the developer supply member. apparatus. 2. The non-magnetic one-component developing device according to claim 1, wherein the gap at the bottom of the developing unit is in a range of 0.2 to 2.0 mm. 3. The non-magnetic one-component developing apparatus according to claim 1, wherein an upper position of said opening is closer to a developer supply member than a lower position. 4. The method according to claim 1, wherein the tip of the developer delivery member is located at a position closer to the lower portion of the opening than the horizontal direction.
Claim 1 wherein a blade member having an angle of ゜ is provided.
Item 1. The non-magnetic one-component developing device according to Item 1.