JPH08248753A - Developing device and image forming device - Google Patents

Abstract

PURPOSE: To constitute a developing device provided with a vertically long toner hopper at the upper part of a developing roller so that sufficiently electrostatically charged toner can be sufficiently supplied to the developing roller, the recovered toner can be effectively reutilized and a color image forming device is easily made compact. CONSTITUTION: The vertically long toner hopper 12Y is provided on the developing roller 11Y and at the vertically upper part thereof and a supply roller 17Y rotated so as to be provided with circumferential speed ratio in an identical direction to the roller 11Y is provided on the roller 11Y and on a more downstream side than the aperture part 16Y of the hopper 12Y. Besides, the layer of the toner 13Y is formed on the roller 11Y by a preliminarily electrostatically charged back layer forming member 21Y so that the carrying force of the toner in the direction of the forming member 21Y from a space part is increased. On the other hand, a recovery roller 18Y dragged with the roller 11Y is provided on the upperstream side than the aperture part 16Y of the hopper 12Y and within a range to -65 deg. from the vertically upper part of the roller 11Y with respect to the rotating direction of the roller 11Y so that the toner is prevented from being retained near the roller 18Y of the toner recovered to the space part 20Y.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device and an image forming apparatus for visualizing an electrostatic latent image with a non-magnetic one-component developer in an image forming apparatus such as a printer or an electrophotographic apparatus.

[0002]

2. Description of the Related Art In recent years, in order to reduce the size and weight of an image forming apparatus such as a laser printer or a copying machine and to reduce the price thereof, a developing apparatus based on a non-magnetic one-component developing system is widely used.

Because of its small size and light weight, this non-magnetic single-component developing system is a full-color type image forming apparatus which requires a plurality of developing devices to be horizontally and continuously arranged. It is considered to be applied, and in order to efficiently arrange a plurality of developing devices in the image forming apparatus, the toner hopper that was conventionally installed to be long in the horizontal direction with respect to the supply roller becomes vertically long above the supply roller. Development of a developing device having a vertical structure provided as described above is in progress.

That is, as shown in FIG. 10, the supply roller 3 is provided near the horizontal position of the developing roller 2 as in the conventional case,
The toner hopper 4, which is conventionally provided horizontally with respect to the supply roller 3 as shown by the dotted line, is provided vertically above the supply roller 3 and is rotated in the direction of arrow c from the opening 4a above the supply roller 3. The toner 6 is supplied to the developing roller 2 at 3, and the toner 6 is conveyed upward by the rotational force of the developing roller 2 rotated in the arrow d direction, and the layer forming member 7 charges the toner 6 and regulates the layer thickness. After that, the toner is brought into contact with the photoconductor 8 to perform development. After the development is completed, the recovery roller 9 provided below the supply roller 3 recovers the residual toner toward the supply roller 3 to erase the development memory. Was there.

[0005]

Conventionally, the toner hopper, which is conventionally provided horizontally with respect to the supply roller, is provided vertically with respect to the supply roller, so that a plurality of developing devices are provided on the conveyor belt like a four-tandem tandem. The miniaturization of a full-color type image forming apparatus that is arranged along the line has been attempted.

However, in such a developing device, in order to reduce the length of the toner hopper in the depth direction,
The arrangement of the supply roller and the like with respect to the developing roller is the case, and the toner hopper is simply arranged vertically from the horizontal to the vertical, and due to its structure, the supply roller is rotated in the opposite direction to the developing roller, so that the toner is not transferred. It was being transported.

Therefore, there is a problem that the surface of the developing roller is easily worn by sliding contact with the supply roller, which hinders its long life.

Further, the conveyance of the toner supplied by the supply roller toward the layer forming member depends on the rotational force of the developing roller, so that the toner conveying force is weak, so that the toner is not transferred to the surface of the developing roller. If the frictional resistance of the developing roller against the toner decreases due to a thin adhesion or the like, the toner slips on the surface of the developing roller and the toner is not sufficiently conveyed to the nip portion with the layer forming member, resulting in poor development due to insufficient toner. Had a problem.

Moreover, because of its structure, most toner is directly conveyed from the toner hopper to the layer forming member without undergoing preliminary charging by the supply roller. Therefore, in order to sufficiently charge the toner only by the layer forming member, The layer forming member must be strongly pressed against the developing roller, or the nip width between the developing roller and the layer forming member must be widened.
The wear of the surface of the developing roller and the adherence of the toner to the surface of the developing roller are more likely to occur, and the above-mentioned defects are more remarkable.

On the other hand, in the case of the collecting roller, in order to re-convey the collected toner to the toner hopper and further to the nip portion of the layer forming member from its arrangement, the toner must be conveyed to the supply roller located substantially vertically above. However, it is difficult to convey the toner, and the toner that has lost its place after collection is clogged and agglomerated in the space between the collection roller and the supply roller, resulting in deterioration of toner characteristics and eventually toner leakage to the outside of the developing device. There is also a serious problem that the surroundings are contaminated and the residual toner cannot be collected, and the developing device cannot be used.

Therefore, if the space between the collecting roller and the supplying roller is enlarged so as to secure a space where the collected toner does not aggregate, the amount of toner that is not reused increases, while the collected toner is reused in the toner hopper. Another problem was that a means for transporting had to be provided, which made the structure complicated and hindered the downsizing of the device.

In view of the above, the present invention has been made to eliminate the above-mentioned problems, and in a developing device which has a vertically long toner hopper above the developing roller and which can realize miniaturization of a color image forming apparatus, the surface of the developing roller is reduced. Wear of the developing roller to extend its life and prevent deterioration of the toner conveying force by the developing roller, thereby preventing deterioration of image quality due to defective toner supply and efficiently collecting the residual toner. An object of the present invention is to provide a developing device and an image forming apparatus that can be reused.

[0013]

The present invention is, as a first means for solving the above problems, a rotatable device for carrying a developer and developing an electrostatic latent image formed on a latent image holding device. Developing means, storage means provided above the developing means for storing the developer and supplying the developer to the developing means through an opening, and above the developing means along the rotation direction of the developing means. And a supply unit that is provided downstream of the opening and is in rotational contact with the developing unit in the same direction and having a peripheral speed difference, and that supplies the developer supplied from the opening of the storage unit to the developing unit. A layer forming unit that is provided downstream of the supply unit along the rotation direction of the developing unit so as to contact the developing unit and thins the developer on the surface of the developing unit; Storage along the direction of rotation A collecting means is provided upstream of the opening of the means and downstream of the developing position by the developing means, and the storage means is provided with a collecting means for collecting the residual developer on the developing means. In addition, the present invention, as a second means for solving the above problems, carries a developer and
A rotatable developing means for developing the electrostatic latent image formed on the latent image holding means, and a developer provided above the developing means for storing the developer and supplying the developer to the developing means through an opening. A storage unit and a supply unit provided above the developing unit and downstream of the opening unit along the rotation direction of the developing unit and supplying the developer supplied from the opening unit of the storage unit to the developing unit. And a layer forming unit that is provided downstream of the supply unit along the rotation direction of the developing unit, in contact with the developing unit, and thins the developer on the surface of the developing unit. Is provided along the rotational direction of the means, downstream from the developing position by the developing means, and vertically above the developing means or within a range of -45 ° from above the vertical direction with respect to the rotational direction of the developing means.
A developing device collecting means is provided, which rotates with the rotation of the developing means, and has a collecting means for collecting the residual developer on the developing means in the storage means.

The present invention also provides a third aspect for solving the above problems.
As a means for carrying a developer, a rotatable developing means for developing an electrostatic latent image formed on the latent image holding means, and a developer provided above the developing means for storing the developer,
Storage means for supplying the developer to the developing means through the opening, and storage means provided above the developing means and downstream of the opening along the rotation direction of the developing means in the same direction as the developing means and at a peripheral speed difference. And a supply unit that supplies the developer supplied from the opening of the storage unit to the developing unit, and the developing unit that is downstream from the supply unit along the rotation direction of the developing unit. A layer forming means which is provided in contact with the developing means and thins the developer on the surface of the developing means; and a developing position along the rotation direction of the developing means, which is downstream of the developing position by the developing means. It is provided vertically above the means or in a range from the vertical above to -45 ° with respect to the rotation direction of the developing means, rotates with the rotation of the developing means, and the residual development on the developing means in the storage means. Times the agent It is intended to provide a recovery means for.

The present invention also provides a fourth aspect for solving the above-mentioned problems.
As a means for forming a color image by forming a developer image of a different color on each of a plurality of latent image holding means, multiple transfer of the developer images on the plurality of latent image holding means to an image forming medium. In the forming means, a plurality of rotatable developing means for carrying the developer of each color and developing each color for each electrostatic latent image formed on the plurality of latent image holding means, and the plurality of developing means. A plurality of storage means provided above to store the developers of the respective colors and supplying the developers of the respective colors to the developing means through an opening, and above the respective developing means along the rotation direction of the developing means. A plurality of units, which are provided downstream of the opening and are in rotational contact with the developing unit in the same direction and having a peripheral speed difference, and which supply the developers of the respective colors supplied from the opening of the storage unit to the developing unit. Supply means,
A plurality of layer forming means provided in contact with the developing means downstream of the supply means along the rotation direction of each developing means, and thinning the developer on the surface of the developing means;
A plurality of units are provided upstream of the opening of the storage unit and downstream of the developing position of the developing unit along the rotation direction of the developing unit, and collect each residual developer on the developing unit in the storage unit. And a means for collecting the same.

The present invention also provides a fifth aspect for solving the above problems.
As a means for forming a color image by forming a developer image of a different color on each of a plurality of latent image holding means, multiple transfer of the developer images on the plurality of latent image holding means to an image forming medium. In the forming means, a plurality of rotatable developing means for carrying the developer of each color and developing each color for each electrostatic latent image formed on the plurality of latent image holding means, and the plurality of developing means. A plurality of storage means provided above to store the developers of the respective colors and supplying the developers of the respective colors to the developing means through an opening, and above the respective developing means along the rotation direction of the developing means. A plurality of supply units that are provided downstream of the opening unit and that supply the developer of each color supplied from the opening unit of the storage unit to the developing unit;
A plurality of layer forming means provided in contact with the developing means downstream of the supply means along the rotation direction of each developing means, and thinning the developer on the surface of the developing means;
It is provided along the rotation direction of each of the developing means, downstream of the developing position by the developing means, and vertically above the developing means or within a range of -45 ° from the vertically above to the rotating direction of the developing means. The storage means is provided with a plurality of recovery means that rotate with the rotation of the development means and recover the residual developers on the development means.

Further, as a sixth means for solving the above-mentioned problems, the present invention forms a developer image of a different color on each of a plurality of latent image holding means, and thereafter, develops on the plurality of latent image holding means. In an image forming means for obtaining a color image by multiple transfer of an agent image onto an image forming medium, a developer of each color is carried and each color is formed for each electrostatic latent image formed on the plurality of latent image holding means. A plurality of rotatable developing means for developing, and a plurality of storage means provided above the plurality of developing means for storing the developer of each color and supplying the developer of each color to the developing means through an opening, It is provided above each of the developing means and downstream of the opening along the rotation direction of the developing means, and is in rotary contact with the developing means in the same direction and with a peripheral speed difference, and is supplied from the opening of the storage means. The developer of each color is A plurality of supplying means for supplying to the image means, and a plurality of supplying means for supplying a thin layer of the developer on the surface of the developing means, which are provided downstream of the supplying means along the rotation direction of the developing means and in contact with the developing means A plurality of layer forming means that are turned into a plurality of layers and downstream of the developing position by the developing means along the rotation direction of each developing means, and vertically above the developing means or from above the vertical direction with respect to the rotation direction of the developing means. Is provided within a range of up to −45 ° and is rotated with the rotation of the developing means, and each storage means is provided with a plurality of collecting means for collecting each residual developer on each developing means. .

[0018]

According to the present invention, by the above means, the toner hopper is provided above the developing roller, and the photosensitive member unit in the color image forming apparatus can be efficiently arranged. In the developing device, the supply roller is provided on the developing roller from the toner hopper opening. Since it is installed downstream and rotates so as to have a peripheral speed difference in the same direction as the developing roller, the load on the developing roller can be reduced and wear on the surface can be reduced compared to the conventional one, so that the toner It is possible to improve the conveying force in the direction of the layer forming means, and further, to precharge all the toner by the supply roller and then convey the toner to the layer forming member to sufficiently charge the toner, resulting in insufficient toner and poor charging. Therefore, it is possible to obtain a good developed image, improve the image quality, and extend the life of the developing roller.

Further, a collecting roller is provided within a range of -45 ° from the vertical position of the developing roller, and is rotated with the rotation of the developing roller to collect the residual toner in the toner hopper, thereby providing a means for carrying. The collected toner can be dropped above the developing roller without any action, and can be more easily conveyed toward the layer forming means. Therefore, unlike the conventional case, the collected toner is not stagnated near the collection roller and falls around and does not stain the surroundings, so that the stain can be prevented and the collected toner can be effectively reused and its characteristic is prevented from being deteriorated. I can.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The principle of the present invention will be described below with reference to FIGS. 10 is a developer of any color in the toner hopper 12 which is a storage means which is vertically elongated above the developing roller 11 which is a supply means, and which contains polyester resin, styrene-acrylic resin or the like as a main component, and a dye, Pigment, C
CA (Charge Control Abil-it)
y, a charge control agent), wax, an external additive, and the like, is a developing device for storing the non-magnetic one-component toner 13. The developing device is provided at a developing position around a photoreceptor 14 which is a latent image holding means described later. There is.

The developing roller 11 is made of conductive urethane rubber having elasticity and, if necessary, ± 100.
A bias voltage of ± 250 V is applied, and arrow e
It is designed to rotate in the direction.

The stirring blade 2 is vertically above the developing roller 11.
2 and a toner hopper 12 having an opening 16 on the bottom surface is provided, and the developing roller 11 and the toner hopper 12 are provided.
Between the vertical direction of the developing roller 11 and the downstream in the rotation direction, and at an arbitrary position downstream of the opening 16, a supply roller which is a supply means made of an elastic body such as foamed urethane rubber subjected to a conductive treatment. 17 is provided so as to bite into the developing roller 11 by about 0.5 to 3 mm so as to obtain a sufficient nip width, and at the time of development, it is rotated in the same direction as the developing roller 11 in the direction of the arrow f, and At the speed (peripheral speed ratio 1), the friction with the developing roller 11 is not generated, and the precharging function of the toner 13 cannot be performed.
The peripheral speed ratio v with respect to 1 is 0 <v <1 or 1 <v <2, more preferably 0 <v <0.75 or 1.2.
It is designed to be rotated so that 5 <v <1.5.

This is because when the peripheral speed ratio is in a stopped state of 0 or in the reverse rotation of less than 0, it does not have the effect of promoting the supply of the toner 13, but if it rotates in the same direction even a little. While toner can be transported along the direction of rotation,
It is prevented that the peripheral speed is too high and the toner 13 is conveyed too much.

To the supply roller 17, in order to further accelerate the supply of the toner 13, ± 100 to the developing bias.
A supply bias of 300 V may be applied.

Further, between the developing roller 11 and the toner hopper 12, from the vertically upper side of the developing roller 11 to -45 with respect to the rotation direction.
The collection roller 1 which is a collection means at an arbitrary position within the range of °
8 are provided. The collecting roller 18 is pressed against the developing roller 11 so as to bite into the developing roller 11 by about 0.1 to 0.4 mm, and is rotated as the developing roller 11 rotates.
In the direction of arrow g, which is the same direction as the developing roller, the developing roller 11
While rotating at the same speed as that of the developing roller 11, the residual toner is removed from the developing roller 11 in an electric potential, so that the shaft is grounded (0
v) or a bias voltage of ± 100 to 300 is applied. However, when the bias voltage is applied, in order to prevent the voltage drop of the developing bias applied to the developing roller 11, the surface of the collecting roller 18 is subjected to a high resistance treatment.

By disposing the collecting roller 18 within a range of up to -45 ° from the vertical direction of the developing roller 11 with respect to the rotating direction, as shown in FIG. 2, the developing roller 11 rotates and its tangential direction. The vector t2 in the horizontal direction becomes larger than the vector t1 in the gravity direction of the force T generated in
The toner 13 written on the developing roller 11 from the collecting roller 18 is easily transported as the developing roller 11 rotates, is mixed with the toner supplied from the toner hopper 12, and is easily reused.

On the other hand, if the collecting roller 18 is provided further upstream than -45 ° with respect to the rotation direction of the developing roller 11, the collected toner must be conveyed on the developing roller 11 against the gravity direction vector t1. The toner conveying force is reduced, the collected toner 13 dropped to the developing roller 11 side is accumulated, and due to the retention of the toner, the phenomenon that the charge characteristics and the toner characteristics of the average particle diameter are changed occurs. , The collection roller 18 is made of urethane rubber,
A cleaning blade 19 for scraping off the toner 13 on the surface of the collecting roller 18 is in contact with the surface.

In the developing device 10, the developing roller 1
1, a space 20 surrounded by the supply roller 17, the toner hopper 12, and the collection roller 18 is formed.

Further, on the downstream side of the supply roller 17 on the developing roller 11, pressure 10 is applied toward the center of the developing roller 11.
〜600 g / cm ² (0.98 × 10 ^-3 〜5.88 × 1
0 ^-2 stainless steel for regulating the layer thickness as well as frictionally charge the toner 13 by pressing in N / mm ^2),
A layer forming member 21 is provided which is a layer forming means made of metal such as copper, phosphor bronze, aluminum, zinc plating, nickel plating, or synthetic resin such as silicon rubber or urethane rubber.

Further, the photosensitive member 14 is uniformly charged to ± 400 to ± 800 V by the charging roller 26 as it rotates in the direction of arrow i, exposed by an exposure head 27 of an optical unit (not shown) according to image information, and electrostatically charged. A latent image is formed and developed by the developing device 10.

That is, in the developing device 10, the toner 13 supplied onto the developing roller 11 through the opening 16 of the toner hopper 12 is conveyed in the direction of arrow e by the rotation of the developing roller 11 and the supplying roller 17, and both rollers 11, It passes through the nip portion between the rollers 17, is lightly charged to the same polarity as the electrostatic latent image by the friction between the rollers 11 and 17, and is conveyed to the layer forming member 21.

Further, the toner 13 obtains a uniform triboelectric charge of ± 5 to ± 20 μC / g due to friction between the developing roller 11 and the layer forming member 21 and is applied in a thin layer on the surface of the developing roller 11, and according to its rotation. The developing position facing the photoconductor 14 is reached. However, at this developing position, the developing roller 1
1 rotates in the same direction or in the opposite direction at a peripheral speed ratio of 1.2 to ² , and is in contact with the photoconductor 14 at a linear pressure of 5 to 500 g / cm ² .

Then, the toner 13 charged to the same polarity as the electrostatic latent image is transferred from the developing roller to the photosensitive member 14 side according to the potential of the electrostatic latent image at the developing position and is developed. After that, in the photoconductor 14, after the transfer roller 30 transfers the toner image to the transfer paper and removes the electric charge, the cleaning device 31 removes the residual toner so that the next image can be formed.

On the other hand, the toner remaining on the developing roller 11 after the completion of the development is collected by the collecting roller 18 and developed by the developing roller 11.
And the recovery roller 18 depending on the potential difference between the recovery roller 18 and the recovery roller 18.
Then, the developing memory on the photoconductor 14 is erased, the developing memory on the photoconductor 14 is erased, the toner is scraped off onto the developing roller 11 by the cleaning blade 19, and is conveyed to the supply roller 17 side for reuse.

Next, a first embodiment of the present invention in which the developing device of the above principle is actually used will be described with reference to FIGS. 3 and 4.

FIG. 3 is a schematic block diagram showing the image forming unit 1 of the color printer. Inside the image forming unit 1, yellow (Y), magenta (M), cyan (C) and black (B) are provided.
K) each of the toners 13Y, 13M, 13C, and 13BK, the four photoconductor units 100Y for performing image formation,
100M, 100C, and 100BK are arranged in parallel along the conveyor belt 36.

Regarding the photoconductor unit 100, each photoconductor unit 100Y, 100M, 100C, 100B
Since all K are composed of the same constituent members, description will be given with reference to an arbitrary one, for example, the yellow photoconductor unit 100Y, and the other photoconductor units 100M, 100C, 100.
The description of BK is omitted.

As shown in FIG. 4, the photoconductor unit 100Y
A charging roller 26Y, an exposure head 27Y, a developing device 10Y, a transfer roller 30Y, and a cleaning device 31Y are sequentially arranged around the photoconductor 14Y.

Reference numeral 37 is a paper feed cassette device (not shown)
After temporarily stopping the transfer paper taken out, the photoconductor 1
The registration roller conveys in the direction of the conveyor belt 36 in synchronization with the electrostatic latent image on 4Y.

Further, a fixing roller 38, a paper discharging roller (not shown), and a paper discharging tray are arranged downstream of the conveyor belt 36.

Next, the developing device 10Y will be described in detail. This developing device 10Y has a total developer capacity of 200 g and a diameter of 1 mm with a layer of conductive urethane rubber formed around the shaft.
A developing bias voltage of -200 V is applied to the 8 mm developing roller 11Y, and the photoreceptor 1 is rotated in the direction of arrow i.
It is adapted to rotate at a peripheral speed ratio of -1.8 in the direction of arrow j, which is the opposite direction of 4Y.

Further, the toner hopper 12 on the developing roller 11Y
Conductive treatment is applied to a position at a rotation angle of 45 ° from above the developing roller 11Y, which is downstream of the Y opening 16Y.
A supply roller 17Y made of foamed urethane rubber and having a diameter of 12 mm, to which a supply bias of 00 V is applied, is provided.
In a state of biting into the developing roller 11Y by about 1 mm, the peripheral speed ratio v = 0.
It is designed to rotate at 5.

On the other hand, a rotation angle of −30 from the vertically upper side of the developing roller 11Y upstream of the opening 16Y of the toner hopper 12Y.
At the position of °, the collecting roller 1 which is coated with polycarbonate resin on the surface of the SUS rod and is connected to the ground (0V)
8Y is provided, and it is about 0.2mm with respect to the developing roller 11Y.
In the bite state, the developing roller 11Y is rotated in the direction of the arrow m at the same speed as the developing roller 11Y as the developing roller 11Y rotates.

Further, as the layer forming member 21Y, a silicon rubber chip of R4 is adhered to the tip of the leaf spring of SUS, and the developing roller 1
It has a pressing force of 50 g / cm ² for 1Y. Next, the operation will be described. When a color image signal is sent to the image forming unit 1 by the start of printing, each device of the image forming unit is driven and each of the photoconductors 14Y to 14BK.
The image forming process is sequentially performed according to the rotation in the arrow y direction. That is, the photoconductors 14Y to 14BK are first uniformly charged to −700V by the charging rollers 12Y to 12BK.

Next, the photoconductors 14Y to 14BK are respectively subjected to yellow, magenta, and
Cyan and black image lights are emitted to form electrostatic latent images corresponding to the image signals. Further, the photoconductors 14Y to 1
4BK is developed by each of the developing devices 10Y to 10BK to form a toner image of each color.

That is, at the start of image formation, the developing roller 11Y is rotated in the direction of arrow j, and the supply roller 17Y is rotated in the direction of arrow k at the peripheral speed ratio v = 0.5 with respect to the developing roller 11Y, while the collecting roller is also rotated. 18Y is the developing roller 11Y
Is rotated in the direction of arrow m at the same speed.

As a result, the toner 13 supplied from the opening 16Y of the toner hopper 12Y and the collecting roller 18Y.
In the space portion 20 in which the collected toner 13 is stored, the toner 13 is conveyed in the direction of arrow j along the rotation direction of the developing roller,
It is precharged between the developing roller 11Y and the supply roller 17Y, and is further conveyed in the layer forming member 21Y direction. Then, the toner 13 is frictionally charged while passing through the layer forming member 21Y, and is uniformly layered on the developing roller 11Y.
Then, the photosensitive member 14Y is developed by being conveyed to a position facing the developing roller 11Y.

After the development is completed, the toner 13 remaining on the developing roller 11Y is collected by the collecting roller 18Y connected to the ground (0V) due to the potential difference between the developing roller 11Y and the developing roller 11Y to which a developing bias of -200V is applied. Collection roller 1
It is transferred to the 8Y side and the development memory is erased. Further, the toner 13 on the collecting roller 18Y is scraped off by the cleaning blade 19 into the space 20, and is again conveyed in the direction of the supply roller 17Y and reused.

On the other hand, in the photoconductor 14Y, after development by the developing roller 11Y, the toner images are sequentially transferred to the transfer paper.

That is, while the toner images are formed on the photoconductors 14Y to 14BK, the transfer paper is taken out from the paper feeding cassette device (not shown) and temporarily stopped at the position of the registration roller 37.

Next, the transfer paper is the photoconductors 14Y to 14BK.
The transfer roller 3 of the conveyor belt 36 is synchronized with the upper toner image.
The toner images are sent to the 0Y position, and the toner images are sequentially transferred from the photoconductors 14Y to 14BK in a multiple transfer manner. After that, the transfer sheet is peeled off from the conveyor belt 36, conveyed to the fixing roller 38, and the toner image is heat-fixed to complete the image, and then the sheet is discharged onto a sheet discharge tray by a sheet discharge roller (not shown).

After the toner image is transferred onto the transfer paper, the photoconductor 14Y goes through the cleaning devices 31Y to 31BK and waits for the next image formation.

Using this image forming section 1, a running test was performed on 5000 sheets of [A4] size solid image, and the toner was stably supplied and sufficient image density was obtained. In addition, the test chart with a print rate of 5% is 10,000
Even in the running test of one sheet, a good image was obtained in which the toner charge amount was kept uniform, there was no fog, and no development memory appeared. Furthermore, good toner supply characteristics were obtained in both running tests of the solid image and the test chart, and in the case of the test chart having a printing rate of 5%, the toner 13Y remaining amount in the developing device 10Y was good at up to 4500 sheets of 20 g. Toner supply characteristics were obtained.

With this structure, the supply roller 17Y rotates in the same direction as the developing roller 11Y, and the developing roller 1Y
The flow of the developer strongly occurs in the rotation direction of 1Y, the conveyance force of the toner 13Y is increased as compared with the conventional case, and the image is not deteriorated due to insufficient supply of toner.

Generally, the toner has an average particle size of 5 to 10 μm.
Since they are fine particles of m, the flowability is poor, and an arch is formed at the opening 16Y of the toner hopper 12Y so that the toner does not flow out. There is a case in which the toner of No. 1 is pressed to cause aggregation, but the toner conveying force is increased as compared with the conventional case, arches and aggregation can be easily broken, and deterioration of fluidity can be prevented.

If the developing roller 11Y is used for a longer period of time,
The surface is abraded, or the toner 13 on the surface of the developing roller 11Y.
Even if Y is lightly adhered, a sufficient toner supply amount can be obtained because the carrying force of the toner 13Y is increased as compared with the conventional case.

Further, the toner 13Y conveyed from the space 20Y of the developing device 10Y to the layer forming member 21Y always passes through the nip portion between the developing roller 11Y and the supply roller 17Y, and both rollers 11Y having a peripheral speed difference, Since it is pre-charged between 17Y, the layer forming member 21Y can easily obtain a sufficient charge amount.

Further, the supply roller 17Y is the developing roller 11Y.
Is arranged on the downstream side in the rotation direction of the developing roller 11Y from above in the vertical direction, and the opening 16Y of the toner hopper 12 is provided above the developing roller 11Y, so that the toner supplied by the supply roller 17Y is conveyed upward as in the conventional case. It is not necessary to transport Tona against gravity so that
A smooth toner flow from the upper side to the lower side can be obtained, and a sufficient toner supply amount can be easily obtained.

Moreover, it is a portion upstream of the developing roller 11Y in the rotational direction from above the vertical direction, and is above the developing roller 11Y at -45.
Since the collection roller 18 can be placed in a space up to °,
The width of the developing device 10Y in the depth direction can be reduced as compared with the related art, and the four photoconductor units 100 arranged along the transport belt 37 can be reduced in the depth direction, and the image forming unit 1 in the color printer can be downsized. Can be easily realized.

Further, in the collecting roller 18Y, the collected toner 13Y can be separated as it is onto the developing roller 11Y in the space 20Y by the cleaning blade 19Y, so that the collected toner 13Y can be removed without using a new conveying means.
Can be easily reused.

Moreover, the collecting roller 18Y is the developing roller 11
The toner is arranged in a range of from −45 ° to the rotation direction from the vertical direction of Y, and the collected toner does not stay on the developing roller 11Y, and the toner charge amount and the average particle diameter change. Even if it is used for a long time, good developing characteristics can be obtained.

Further, since the collecting roller 18Y rotates together with the developing roller 11Y, the developing roller 11Y does not fluctuate in speed, and density unevenness and image disturbance are caused by the fluctuation in speed of the developing roller 11Y. Will not occur.

Further, the collecting roller 18Y is the developing roller 11
The developing roller 11Y is mounted on the developing roller 11Y in a range from vertically above Y to −45 ° with respect to the rotation direction.
With respect to the above, the self-weight is applied together with the pressing force from the outside, and the interlocking with the developing roller 11 can be performed more smoothly.

Therefore, the pressing force for pressing the collecting roller 18Y against the developing roller 11Y from the outside can be reduced as compared with the conventional case, and when a strong pressing force is applied to both ends of the shaft, the shaft bends, and the developing roller 11Y moves in the longitudinal direction. On the other hand, it is possible to prevent the phenomenon that the recovery roller hits unevenly, and it is possible to obtain good toner recovery.

Next, a second embodiment of the present invention will be described with reference to FIG. However, in the second embodiment, the arrangement of the supply roller 17Y and the collecting roller 18Y in the first embodiment is reversed, and further, the layer regulating means is formed in a roller shape and the arrangement thereof is also reversed. 14Y, the developing roller 11Y rotates in the same direction so that the peripheral speed ratio v = 1.8. Since the other parts are the same as those in the first embodiment, the same parts are designated by the same reference numerals. The description is omitted.

That is, the photoconductor 14 rotated in the direction of arrow i.
The opening 16Y of the toner hopper 12Y on the developing roller 11Y, which is rotated at a peripheral speed ratio of 1.8 in the direction of arrow n in the same direction as Y.
The rotation angle 45 from the vertically upper side of the developing roller 11Y on the further downstream side.
At the position of °, the same supply roller 17Y as that of the first embodiment is provided.
Is provided to rotate in the direction of arrow o. On the other hand, at the position of a rotation angle of -40 ° from the vertically upper side of the developing roller 11Y upstream of the opening 16Y of the toner hopper 12Y, the same collecting roller 18Y as that of the first embodiment is rotated around the developing roller 11Y in the arrow p direction. It is designed to be rotated.

Further, the supply roller 17 on the developing roller 11Y
Downstream of Y, the developing roller 1 is made of stainless steel.
A roller-shaped layer forming member 40Y having a diameter of 14 mm is provided that is pressed against 1Y so as to have a pressing force of 30 g / cm ² .

That is, during the developing operation, as in the first embodiment, the toner 13Y in the space 20Y is conveyed in the direction of the arrow n by the rotation of the developing roller 11Y and the supplying roller 17Y, and between the developing roller 11Y and the supplying roller 17Y. And is pre-charged, and is further conveyed in the direction of the layer forming member 40Y. While passing through the layer forming member 40Y, the toner 13Y is triboelectrically charged and is uniformly layered on the developing roller 11Y.
After this, the photoconductor 14Y is developed.

After the development, the residual toner 13Y on the developing roller 11Y is collected by the collecting roller 18Y and the developing roller 11Y.
Due to the potential difference from Y, it is transferred to the side of the collection roller 18Y, scraped off by the cleaning blade 19 into the space 20, and again conveyed in the direction of the supply roller 17Y and reused.

Then, using this developing device 50Y, [A
4] A running test of 5,000 sheets with a full size solid image and a 100% on a test chart with a printing rate of 5%
When a running test of 00 sheets was carried out, the toner 13Y was sufficiently supplied in any of them in the same manner as in the first embodiment, the density was not decreased, and the charge amount of the toner was kept uniform and fog and fog were reduced. A clear image without a development memory was obtained.

Moreover, since the developing roller 11Y is rotated in the same direction as the photosensitive member 14Y, the speed difference at the nip portion between the developing roller 11Y and the photosensitive member 14Y is smaller than that in the first embodiment, and the first difference is obtained. Vibration and speed fluctuation of the photoconductor 14Y can be suppressed as compared with the embodiment, and density unevenness and image disturbance due to such vibration and the like can be prevented.

Next, a third embodiment of the present invention will be described with reference to FIGS.
Will be described with reference to. However, in the third embodiment, the supply roller 17Y in the second embodiment is arranged vertically above the developing roller 11Y, the peripheral speed ratio v is 0.5 with respect to the developing roller 11Y, and the collecting roller 18Y is developed. The roller 11Y is arranged below the center of the roller 11Y and the biting into the developing roller 11Y is 0.3 mm. Further, the layer forming member 42Y is formed into a blade shape, and the other parts are the same as the second embodiment including the rotation directions of the rollers 11Y, 17Y and 18Y.

Then, using this developing device 60Y, [A
4] A running test of 5,000 sheets was performed on a full-size solid image. As a result, the toner was stably supplied and sufficient image density was obtained as in the second embodiment.

However, the collecting roller 18Y is the developing roller 11Y.
The toner 13 near the collecting roller 18Y in the space portion 20Y is disposed below and is close to the supply roller 17Y.
Y is not conveyed to the supply roller 17Y and remains, so that the toner 13Y is not reused. A running test using a test chart with a printing rate of 5% shows that toner 13Y needs to be replenished after printing about 3500Y. Became.

Further, the particle size distribution of the residual toner collected by the collecting roller 18Y is slightly wider than the particle size distribution of the replenishment toner in the toner hopper 12Y, and the collecting roller 18Y is also used.
Since the residual toner having a wide particle size distribution increases near Y and is not reused, the particle size distribution of the toner on the developing roller 11 gradually changes during a large number of printings, and the toner size of the toner on the developing roller 11 gradually changes. The charging characteristics were changed, and the image quality was deteriorated due to an increase in fogging.

The particle size distributions at the start of image formation and after the running test of 10,000 sheets were measured by a running test of 10,000 sheets according to a test chart, and as shown in FIG. In comparison, the particle size distribution of the toner after the running test of 10,000 sheets was expanded.

The fog on the photosensitive member corresponding to the non-image portion of the test chart was 0.9% at the start of image formation, but was 5.6% after the running test of 10,000 sheets.
Was raised.

Further, the developing memory appeared in the central portion of the image from about 7,000 sheets, and about 9000 sheets, leakage of the collected toner occurred around the collecting roller 18Y.

With this structure, the collecting roller 18Y
Since the installation position of is low, the conveying force of the toner after collection is reduced, but sufficient toner supply can be obtained by the supply roller 17Y, so that good image density can be obtained.

Next, a fourth embodiment of the present invention will be described with reference to FIGS.
Will be described with reference to. However, in the fourth embodiment, the supply roller 17Y in the third embodiment is not provided, and the recovery roller 18Y is located at -30 ° with respect to the rotation direction of the developing roller 11Y from vertically above the developing roller 11Y. At the position, the bite into the developing roller 11Y is set to be 0.2 mm. The toner hopper 12Y opening 16Y is provided with a supply stirring blade 43Y for accelerating the supply of the toner 13Y, but is the same as the third embodiment including the rotation directions of the rollers 11Y and 18Y.

When a running test was conducted using the developing device 70Y with a test chart having a printing rate of 5%, a good quality image was obtained without developing memory on the image, and the toner near the collecting roller 18Y was obtained. No leaks occurred.

At the start of image formation and 1 of the test chart.
When the particle size distribution of each of the particles after running the running test of 0000 sheets was measured, they were almost the same as shown in FIG.

However, the fog was slightly higher from the beginning of image formation both on the paper and on the photoconductor, and for the image on the transfer paper, it was 0.57% at the start of image formation, and the running test of 10,000 sheets was performed. After that, it rose to 0.83%. On the other hand, on the photoconductor, it was 0.52% at the start of image formation and increased to 7.1% after the running test of 10,000 sheets. This is presumably because the toner 13Y is not precharged by the supply roller, and the layer forming member 42Y only triboelectrically charges the toner 13Y, so that a sufficient charge amount cannot be obtained.

Further, a running test was conducted on a solid image of [A4] size.
Approximately 2 when the amount of residual developer in the developing device 10Y is approximately 80 g
Poor developer supply occurred at 00 sheets.

According to this structure, since the supply roller is not provided, the toner supply failure occurs, but the development memory on the image can be prevented from being generated, and the collected toner does not stagnate. The toner does not leak from the vicinity, and good toner recovery and reuse can be achieved.

Moreover, the collecting roller 18Y is connected to the developing roller 11
Since it is arranged at a position of −30 ° upstream of the vertical direction of Y in the rotational direction, the width of the developing device 70Y in the depth direction can be reduced, and the four photoconductor units 100 arranged along the transport belt 37. The image forming unit 1 in the color printer can be easily miniaturized.

The present invention is not limited to the above-mentioned embodiments, and various design changes can be made. If the developer can be easily transferred from the supplying means to the developing means and further from the developing means to the collecting means,
The material or the potential difference between the respective means may be set arbitrarily.

The layer regulating means may have any shape such as a leaf spring, a rod shape, a roller shape, and a chip shape. To accelerate the charging of the developer, a voltage is applied to give an injection charge to the developer. Is also good.

[0089]

As described above, according to the present invention, there is provided the supplying means which is rotated vertically above the developing means in the same direction as the developing means downstream of the developing means in the rotational direction. By doing so, the developer supplied from the storage means and the recovery means above the developing means to the developing means can be pre-charged without increasing the abrasion of the developing means, and the developer conveying force in the direction of the layer forming means can be increased. It is possible to secure a good supply of the sufficiently charged developer, and it is possible to obtain a high-quality image without causing fogging due to insufficient charge or causing blurring due to insufficient developer.

Moreover, since the supply means is disposed on the developing means downstream of the storage means, the developer supplied from the storage means can be easily conveyed toward the layer forming means, and the supply of the developer is further facilitated. .

Further, by disposing the collecting means interlocking with the developing means in the range from vertically above the developing means to -45 ° with respect to the rotation direction, the developer dropped from the collecting means onto the developing means is in the vicinity of the collecting means. It can be easily reused without being retained in the developer, does not cause a change in the charge amount of the developer or the average particle size, and can obtain good development characteristics and thus a good image even after long-term use. .

Moreover, since the collecting means can be disposed above the developing means, the width of the developing device in the depth direction can be reduced as compared with the conventional one, and the size of the device can be reduced when a plurality of developing devices such as a color printer are installed side by side. It can be realized effectively.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a photoconductor unit for explaining the principle of the present invention.

FIG. 2 is a schematic explanatory diagram of a vector generated in a tangential direction of a developing roller showing the principle of the present invention.

FIG. 3 is a schematic configuration diagram illustrating an image forming unit according to a first embodiment of the present invention.

FIG. 4 is a schematic configuration diagram illustrating a developing device according to a first embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing a developing device according to a second embodiment of the present invention.

FIG. 6 is a schematic configuration diagram showing a developing device according to a third embodiment of the present invention.

FIG. 7 shows a toner particle size distribution and an integrated amount of toner volume particle size according to a third embodiment of the present invention, (a) is a graph at the start of image formation, and (b) is its 10,000-sheet running. It is a later graph.

FIG. 8 is a schematic configuration diagram showing a developing device according to a fourth embodiment of the present invention.

FIG. 9 shows a toner particle size distribution and an integrated amount of toner volume particle size in a fourth embodiment of the present invention, (a) is a graph at the start of image formation, and (b) is its 10,000-sheet running. It is a later graph.

FIG. 10 is a schematic configuration diagram showing a conventional developing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Image forming part 10 ... Developing device 11 ... Developing roller 12 ... Toner hopper 13 ... Toner 14 ... Photosensitive drum 17 ... Supply roller 18 ... Collection roller 20 ... Layer forming member 100 ... Photosensitive unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Osamu Takagi, 70 Yanagi-cho, Saiwai-ku, Kawasaki-shi, Kanagawa, Toshiba Yanagimachi Co., Ltd. (72) Yoshiya Hashimoto, 70, Yanagi-cho, Sachi-ku, Kawasaki, Kanagawa Toshiba Yanagi-cho, Toshiba Inside the factory (72) Inventor Yasuyuki Fukudome 70 Yanagicho, Saiwai-ku, Kawasaki-shi, Kanagawa Toshiba Yanagimachi Factory

Claims (6)

[Claims] 1. A rotatable developing means for carrying a developer and developing an electrostatic latent image formed on a latent image holding means; and a developing means provided above the developing means for storing the developer and opening it. A storage means for supplying the developer to the developing means from a portion, and a downstream side of the opening along the rotation direction of the developing means above the developing means, in the same direction and at a peripheral speed difference to the developing means. A supply unit that is in rotary contact with the supply unit and that supplies the developer supplied from the opening of the storage unit to the developing unit, and the developing unit downstream from the supply unit along the rotation direction of the developing unit. A layer forming means which is provided in contact with the developing means for thinning the developer on the surface of the developing means, and which is developed by the developing means upstream from the opening of the storage means along the rotation direction of the developing means. Downstream of position Vignetting, developing apparatus is characterized by comprising a recovery means for recovering the residual developer on the developing means to the storage means. 2. A rotatable developing means for carrying a developer and developing an electrostatic latent image formed on a latent image holding means; and a developing means provided above the developing means for storing the developer and opening it. Storage means for supplying the developer to the developing means from a portion, and is provided above the developing means and downstream of the opening along the rotation direction of the developing means, and is supplied from the opening of the storage means. And a supply means for supplying the developer to the developing means, and a contacting means provided on the surface of the developing means downstream of the supplying means along the rotation direction of the developing means. A layer forming means for thinning the developing means, downstream of the developing position by the developing means along the rotation direction of the developing means, and vertically above the developing means or from above the vertical direction with respect to the rotation direction of the developing means. -
A developing device, which is provided in a range up to 45 °, rotates with the rotation of the developing means, and has a collecting means for collecting the residual developer on the developing means in the storing means. 3. A rotatable developing means for carrying a developer and developing an electrostatic latent image formed on a latent image holding means; and a developing means provided above the developing means for storing the developer and opening it. A storage means for supplying the developer to the developing means from a portion, and a downstream side of the opening along the rotation direction of the developing means above the developing means, in the same direction and at a peripheral speed difference to the developing means. A supply unit that is in rotary contact with the supply unit and that supplies the developer supplied from the opening of the storage unit to the developing unit, and the developing unit downstream from the supply unit along the rotation direction of the developing unit. A layer forming means that is provided in contact with the developing means and thins the developer on the surface of the developing means; and a developing means along the rotation direction of the developing means, downstream of the developing position by the developing means. Vertically above or From serial vertically upward with respect to the rotational direction of said developing means -
A developing device, which is provided in a range up to 45 °, rotates with the rotation of the developing means, and has a collecting means for collecting the residual developer on the developing means in the storing means. 4. A color image is obtained by forming a developer image of a different color on each of the plurality of latent image holding means and then multiple-transferring the developer images on the plurality of latent image holding means onto an image forming medium. In the image forming means, a plurality of rotatable developing means for carrying a developer of each color and developing each color for each electrostatic latent image formed on the plurality of latent image holding means; A plurality of storage means provided above the means for storing the developer of each color and supplying the developer of each color to the developing means through an opening; and a plurality of storage means above the developing means along the rotation direction of the developing means. Are provided downstream of the opening and are in rotational contact with the developing means in the same direction and having a peripheral speed difference, and a plurality of developers of the respective colors supplied from the opening of the storage means are supplied to the developing means. Supply means, and each of the developing means A plurality of layer forming means provided in contact with the developing means downstream of the supply means along the rotation direction and thinning the developer on the surface of the developing means; and a rotation direction of each developing means. And a plurality of collecting means for collecting each residual developer on the developing means in each of the storing means provided upstream of the opening of the storing means and downstream of the developing position of the developing means. An image forming apparatus characterized by the above. 5. A color image is obtained by forming a developer image of a different color on each of the plurality of latent image holding means and then multiple-transferring the developer images on the plurality of latent image holding means onto an image forming medium. In the image forming means, a plurality of rotatable developing means for carrying a developer of each color and developing each color for each electrostatic latent image formed on the plurality of latent image holding means; A plurality of storage means provided above the means for storing the developer of each color and supplying the developer of each color to the developing means through an opening; and a plurality of storage means above the developing means along the rotation direction of the developing means. And a plurality of supply units that are provided downstream of the opening unit and that supply the developers of the respective colors supplied from the opening unit of the storage unit to the developing unit; Downstream of the supply means, the developer A plurality of layer forming means provided in contact with the developing means for thinning the developer on the surface of the developing means, along the rotation direction of each developing means, downstream from the developing position by the developing means, and It is provided vertically above the developing means or within a range from the vertical above to −45 ° with respect to the rotation direction of the developing means, rotates with the rotation of the developing means, and the respective developing means in the respective storage means. An image forming apparatus comprising: a plurality of collecting means for collecting the above-mentioned residual developers. 6. A color image is obtained by forming a developer image of a different color on each of the plurality of latent image holding means and then multiple-transferring the developer images on the plurality of latent image holding means onto an image forming medium. In the image forming means, a plurality of rotatable developing means for carrying a developer of each color and developing each color for each electrostatic latent image formed on the plurality of latent image holding means; A plurality of storage means provided above the means for storing the developer of each color and supplying the developer of each color to the developing means through an opening; and a plurality of storage means above the developing means along the rotation direction of the developing means. Are provided downstream of the opening and are in rotational contact with the developing means in the same direction and having a peripheral speed difference, and a plurality of developers of the respective colors supplied from the opening of the storage means are supplied to the developing means. Supply means, and each of the developing means A plurality of layer forming means provided in contact with the developing means downstream of the supply means along the rotation direction and thinning the developer on the surface of the developing means; and a rotation direction of each developing means. Is provided downstream of the developing position by the developing means and vertically above the developing means or within a range of -45 ° with respect to the rotation direction of the developing means from vertically above the developing means. An image forming apparatus, comprising: a plurality of collecting means that rotate together with each other and collect in each storage means each residual developer on each developing means.