JP3261812B2 - Stirrer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stirring device for stirring a developer in a developing container.

[0002]

2. Description of the Related Art Conventionally, for example, there is an apparatus such as an electrostatic recording apparatus which stirs a developer in order to keep the concentration of the developer constant. Such a stirrer is configured such that two stirrers called auger rolls having a plurality of blades on a rotating shaft are arranged in parallel, and one is used for rightward feed and the other is used for leftward feed to rotate the developer. Circulating the developer, or disposing one stirrer inside the other cylindrical stirrer, and rotating the blades in the opposite winding direction or rotating direction to rotate the developer. What is circulated is known.

[0003]

However, the above-mentioned stirrer has a complicated mechanism due to the use of two stirrers, so that not only maintenance is troublesome but also product cost is reduced. However, there was a problem that it became expensive.

An object of the present invention is to provide a stirrer comprising one stirrer in view of the above-mentioned conventional situation.

[0005]

The structure of the stirring device according to the present invention will be described below. The present invention is applied to a stirring device which is provided in a container containing a developer and stirs the fluid by rotating.

The stirring device of the present invention comprises a rotating shaft, a first stirring blade fixed coaxially at a predetermined angle to the rotating shaft and having a substantially semicircular cross-sectional shape with a radius R1. A substantially semi-circular cross-section fixed to the rotating shaft in the same plane as the first stirring blade and rotationally symmetrical with respect to the rotating shaft and having a width of an inner cavity of approximately R1 and an outer radius of R2. And a second stirring blade having a shape. By the rotation of the rotation shaft, the first stirring blade conveys the developer in a first direction close to and parallel to the rotation shaft, and the second stirring blade transfers the developer outside the rotation shaft. In this configuration, the sheet is conveyed in a second direction opposite to the first direction.

[0007]

According to the present invention, when the rotating shaft rotates, the first stirring blade and the second stirring blade fixed to the rotating shaft rotate. By the rotating first stirring blade, the developer is conveyed in the first direction close to and parallel to the rotation axis while passing through the cavity of the second stirring blade. Further, the developer is conveyed in the second direction opposite to the first direction outside the rotation shaft by the second stirring blade that also rotates.

Thus, even with a stirrer including one stirrer, the developer can be transported in the first and second opposite directions.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a schematic cross-sectional view showing the entire configuration of the electrostatic recording device according to one embodiment. In FIG. 1, a paper feed cassette 1 stores and stores plain paper P, and is removably inserted into a side of the main unit. Above the leading end of the inserted paper feed cassette 1, a paper feed roller 2 is disposed so as to be rotatable in a counterclockwise direction indicated by an arrow A. A standby roll pair 3 is disposed in front of the paper feed roller 2 to temporarily stop the advance of the paper P fed by the paper feed roller 2, adjust its transport posture, and transfer the paper P to a recorded image. It is transported downstream in synchronization with the timing.

Downstream of the standby roll pair 3, a paper transport path 4 extending obliquely downward from the standby roll pair 3 is provided, and a cylindrical electrode 5 and a transfer roll 6 are formed in front of the paper transport path 4. An image transfer unit T is provided. Image transfer unit T
Transfers the toner image transferred onto the peripheral surface of the cylindrical electrode 5 and conveyed in the recording image forming unit U described later to the lower surface of the sheet P. On the downstream side of the image transfer unit T, an air suction type conveyance belt 7 is stretched in a substantially horizontal direction, and conveys the paper P while sucking it up. A fixing device 8 is disposed downstream and forward of the conveyor belt 7. The fixing device 8 includes a heating roll 8a and a pressing roll 8b, and while nipping and transporting the paper P between the two rolls 8a and 8b,
The toner image transferred to the lower surface of the sheet is thermally fixed. The paper P on which the toner image has been thermally fixed is sequentially stacked on the paper output tray 10 in a face-down state with the image side down from the output port 9.

The cylindrical electrode 5 forming the image transfer portion T in pair with the transfer roll 6 is disposed on the upper right side of the recording image forming unit U, and is disposed diagonally lower left. The toner image is transferred from the developing unit 12.

FIG. 3 is a cross-sectional view of the developing unit 12. As shown in FIG.
As shown in FIG. 1, the developing unit 12 includes a cylindrical developing sleeve 13 and a drive rotatable magnet roll 1 which is coaxially disposed and built in the cylinder of the developing sleeve 13.
4 and the peripheral surface on the cylindrical peripheral surface of the developing sleeve 13 is substantially 1
And the recording electrode sheet 15 laid down and divided by ４. A lower portion of the peripheral surface of the developing sleeve 13 opposite to the side on which the recording electrode sheet 15 is laid is provided, and a scraping plate 16 is erected vertically with its tip abutting.

A flat portion 13a is formed on the peripheral surface of the upper portion of the developing sleeve 13, and above a substantially half area upstream thereof,
Recording electrode EL formed at the tip of recording electrode sheet 15
Is located. The recording electrode EL is a spring plate material (not shown) curved to have substantially the same curvature as the peripheral surface of the developing sleeve 13.
It is laid on top and protrudes in a curved shape. As a result, the recording electrode EL forms a recording portion W composed of a minute gap between the recording electrode EL and the peripheral surface of the cylindrical electrode 5 while being elastically supported in a hollow state.

A flat portion 13b is formed on the upstream side of the flat portion 13a of the developing sleeve 13, and an end on which the circuit element 17 of the recording electrode sheet 15 is mounted is laid on the flat portion 13b. . The flat portion 13b is configured to facilitate installation of the circuit element 17 on the recording electrode sheet 15. A cover film 18 made of a non-magnetic material is disposed to cover the recording electrode sheet 15 and the circuit element 17 laid on the flat portion 13b so as to be curved with substantially the same curvature as the peripheral surface of the developing sleeve 13. The cover film 18 forms a developer conveying path in the direction of the recording portion W in the counterclockwise direction indicated by the above-mentioned arrow B, thereby preventing the developer d from directly contacting the circuit element 17. The element 17 is prevented from being damaged by friction with the developer d.

The magnetic roll 14 incorporated in the developing sleeve 13 has different magnetic poles alternately magnetized on its peripheral surface, and rotates clockwise as indicated by an arrow C in FIG. Due to this rotation, a rotating magnetic field that rotates the magnetic carrier particles in the developer d is formed on the outer peripheral surface of the developing sleeve 13. Due to this magnetic field, the developer d circulates and flows horizontally in the vicinity of the bottom of the developing sleeve 13 as described later.
Is attracted to the peripheral surface of the developing sleeve 13 and is conveyed on the cover film 18 in a counterclockwise direction indicated by an arrow B in a direction opposite to the rotation direction of the magnet roll 14.

The amount of the developer d conveyed upward along the surface of the cover film 18 is regulated upstream of the recording section W where the cylindrical electrode 5 approaches and the conveyance path is narrowed, and the developer accumulation Rt is reduced. Form. Then, the developer pool Rt
The developer particles that have moved far from the transport path (the surface of the recording electrode sheet 15) are separated from the magnetic field of the magnet roll 14 and fall naturally as indicated by the arrow F in FIG. Merge into agent d. Due to this natural fall,
The developer forming the developer pool Rt is automatically controlled to an appropriate amount, the developer carried into the recording unit W is controlled to an appropriate amount, and the elastically supported recording electrode EL and the peripheral surface of the cylindrical electrode 5 are controlled. The developer particles are smoothly carried in an appropriate amount into the minute gap of the recording portion W between the recording portions W, and are held flexibly.

A flat portion 13c is formed immediately downstream of the flat portion 13a of the developing sleeve 13. The flat portion 13c is formed to quickly convey the residual developer d 'carried out without being transferred to the cylindrical electrode 5 at the recording portion W to the downstream side. By removing the peripheral surface of the developing sleeve 13 to form the flat portion 13c, the developer conveying path (the surface of the flat portion 13c) can be compared with a case where no cutting is performed.
Is closer to the magnet roll 14, and the closer the closer, the stronger the magnetic force of the magnet roll 14, and the strong magnetic force allows the residual developer d 'to be quickly conveyed.
Therefore, there is no possibility that the developer recorded image formed on the peripheral surface of the cylindrical electrode 5 is disturbed by the residual developer d '.

FIG. 4 is a perspective view of the recording electrode sheet 15. As shown in the figure, the recording electrode sheet 15 has a large number of recording electrode wires 15a made of a non-magnetic conductive material arranged at a predetermined fine pitch in a film width direction on a base film 15b made of a flexible insulating material. Have been. The recording electrode line 15a is connected to the recording electrode EL at one end of the sheet.
Is formed, and is covered with an insulating protective material (not shown) except for the recording electrode EL portion. A plurality of circuit elements 17 for driving the recording electrodes EL are mounted on the other end of the sheet as described above. Each of these circuit elements 17 has a recording electrode line 1 divided into appropriate numbers.
5a is connected. The number of the recording electrode lines 15a, that is, the number of the recording electrodes EL corresponds to the maximum number of data for one main scanning line of an image.

Further, by arranging the circuit element 17 for driving the recording electrode EL on the upstream side of the peripheral surface of the developing sleeve 15 as described above, as shown in FIG.
Can be disposed so as to protrude in the forward direction with respect to the clockwise rotation direction indicated by the arrow E of the cylindrical electrode 5. As a result, the recording electrode E
There is no risk of damaging L.

The circuit element 17 is connected to a central control unit (not shown) for controlling the entire image recording operation of the main unit. The central control unit sends a signal corresponding to the recording information to the circuit element 17 when recording an image, and selectively sends a signal for cleaning untransferred toner to a mechanism driving unit and the like when not recording.

Then, in the recording section W where the peripheral surface of the cylindrical electrode 5 is rotating and moving with a small gap with respect to the recording electrode EL, the developer d is carried in by an appropriate amount as described above. The element 17 selectively applies a recording voltage to the recording electrode EL according to the recording data under the control of the central control unit.

In this case, when the 1-bit recording data is, for example, "H", the corresponding recording electrode EL is -20 in this embodiment.
A voltage of 0 V (ON voltage) is applied. In this example, a bias of −50 V is applied to the cylindrical electrode 5 facing the recording electrode EL by the bias power supply 5a. Therefore, an electric field based on a potential difference of 150 V is formed from the cylindrical electrode 5 to the recording electrode EL. When the developer d passes through the recording portion W in which such an electric field is formed while contacting the peripheral surface of the cylindrical electrode 5, the negatively charged toner particles move to a higher potential. Therefore, -20
Only the toner particles on the recording electrode EL to which the ON voltage of 0 V is applied are selectively transferred onto the peripheral surface of the cylindrical electrode 5 to form a one-dot toner image. On the other hand, when the 1-bit recording data is “L”, the ground voltage (off voltage) is applied to the corresponding recording electrode EL. As a result, in this case, an electric field is generated from the cylindrical electrode 5 to the recording electrode EL in the opposite direction based on a potential difference of −50 V, and the negative toner particles are not transferred while being held by the recording electrode EL.

As described above, the potential of each recording electrode EL is selectively controlled to -200 V and the ground voltage in accordance with the input recording data, and a toner recording image is formed on the surface of the cylindrical electrode 5 in the recording section W. . The density of the toner recorded image is adjusted by changing the voltage of the bias power supply 5a. An appropriate adjustment range of the bias is 0 to -50 V, and the image density is higher as the bias is closer to 0 V.

The above-mentioned developing section 12 is provided in the recording image forming unit U shown in FIG. FIG. 5 is an enlarged sectional view of the recording image forming unit U. As shown in the figure, the recording image forming unit U has a toner storage tank 20 on the upper left side, and the developing sleeve 13 on the upper right side.
A developing unit including a magnet roll 14, a recording electrode sheet 15, and the like is provided. A development recording tank 21 is formed below the recording image forming unit U, and contains a two-component developer therein.

In the toner storage tank 20, replenishment toner t0 is provided.
Is stored. The toner storage tank 20 and the development recording tank 21
A toner supply port Os is formed at the boundary with the toner supply port Os, and a toner supply roller 23 is provided at the toner supply port Os.
The toner replenishing roll 23 is rotated in accordance with the toner concentration of the developer d flowing in the development recording tank 22, and supplies a replenishing toner t0 into the development recording tank 21 by an appropriate amount to control the toner concentration within an appropriate range. I do. In this example, the developer is
Although a two-component developer is used, the developer is not limited to a two-component developer, and may be a one-component developer such as an insulating resin, a magnetic toner including magnetic fine powder and colorant particles, and in this case,
The above-described control of the toner density is unnecessary.

A stirring device 24 is provided in the development recording tank 21.
Are arranged. This stirring device 24 is used for the development recording tank 21.
This is a device that circulates the developer d in the horizontal direction while stirring it. The developing sleeve 1 is provided on the surface layer of the circulating developer d.
The developer d is conveyed on the developing sleeve 13 in the counterclockwise direction indicated by the arrow H in the drawing toward the recording portion W by the magnetic force of the magnet roll 14. As described above, the developer d is transferred to the cylindrical electrode 5 in the recording unit W according to the recording information, forms a toner image, is conveyed upward with the rotation of the cylindrical electrode 5, and moves from left to right as indicated by the arrow G. The paper P is transferred onto the front surface (the lower surface in the figure) of the conveyed paper P by the transfer roll 6.

FIG. 1 is a perspective view of a stirring device 24 provided in the above-described development recording tank 21. 6 (a) is a side sectional view, FIG. 6 (b) is a sectional view taken along the line AA 'in FIG. 6 (a), and FIG. 6 (c) is a sectional view taken along the line BB' in FIG. Is shown.

As shown in the above-mentioned figure, the stirring device 24 has a rotating shaft 25, and a plurality of stirring blades 26
Are fixed at equal intervals. Each of these stirring blades 26
Comprises a first stirring blade 26a and a second stirring blade 26b, and the first stirring blade 26a and the second stirring blade 26b are integrally formed in one plane. Then, as shown in FIG. 6B, AA 'parallel to the plane of the stirring blade 26 is used.
When viewed in cross section (corresponding to a plan view of the stirring blade 26), the overall shape is slightly elliptical. Each stirring blade 26 includes a first stirring blade 26a and a second stirring blade 26 formed integrally.
b (a center line A vertically dividing the cross section AA 'in the vertical direction) are attached to the rotating shaft 24 with a predetermined inclination of a wide angle .theta.1 and a narrow angle .theta.2. ing.

Due to the inclination with respect to the rotating shaft 24, the stirring blade 26 is moved to the B-axis perpendicular to the rotating shaft 24 as shown in FIG.
When viewed in section B ', the first stirring blade 26a has a substantially semicircular shape with a radius R1, and the second stirring blade 26b has a radius R1.
2 is formed into a circular arc having a constant width obtained by cutting the inside of a large semicircle by the radius R1.

When the rotating shaft 25 rotates in any direction in a state where the stirring blade 26 has such an inclination, for example, a direction indicated by an arrow J (a direction in which the right screw advances to the left in the drawing). , The developer d is stirred and conveyed from the surface forming the narrow angle θ2 of the stirring blade 26 to the surface forming the wide angle θ1. Therefore, as shown in FIG. 6A, the first stirring blade 26a stirs and conveys the developer d in the X1 direction (right direction in the figure), and the second stirring blade 26b moves in the opposite direction to the X1 direction. The developer d is agitated and transported in the Y1 direction (the left direction in the figure).

That is, the first stirring blade 26a is connected to the rotating shaft 2
5 stirs and conveys the developer d in a cylindrical area 27 having a radius R1 in the X1 direction, and the second stirring blade 26b
The developer d in a cylindrical area 28 having a radius from R1 to R2 is stirred and transported in the Y1 direction. As a result, the developer d flows and circulates in the horizontal direction (perpendicular to the plane of the drawing) along the stirring device 24 in the development recording tank 21 shown in FIG.

The rotation direction of the rotation shaft 25 may be clockwise or counterclockwise. For example, as shown in FIG. 7, even when the developer d rotates in the direction indicated by the arrow K opposite to that in FIG. 6 (the direction in which the right-hand screw advances to the right in FIG. 6), the developer d reduces the narrow angle θ2 of the stirring blade 26. There is no change in the stirring and conveyance from the surface to the surface forming the wide angle θ1. That is, in this case as well, the first stirring blade 26a moves the developer d in the X2 direction (right direction in the figure). Is stirred and conveyed, and the second stirring blade 26b stirs and conveys the developer d in the opposite Y2 direction (left direction in the figure).

As described above, the developer d in the developing recording tank 21 can be stirred and flow and circulate in the horizontal direction by using only one stirring device 24 having a simple structure. still,
In the present embodiment, the first stirring blade 26a and the second stirring blade 26b are integrally formed in the same plane. However, the present invention is not limited to this. For example, as shown in FIG. 26a 'and the second stirring blade 26b' may be separated and fixed alternately to the rotating shaft. Various methods of attaching the first stirring blade and the second stirring blade to the rotating shaft are conceivable. Can be

[0034]

As described in detail above, according to the present invention, for example, in an electrostatic recording apparatus, the developer in the development recording tank is horizontally stirred by using one auger roll (stirrer). Since the stirrer can be flowed and circulated, the mechanism of the stirrer can be simplified, so that the handling is not troublesome and the efficiency of the maintenance work is improved. Further, the cost of the product is reduced because the mechanism of the stirring device is simple. Furthermore, since a sufficient mechanism can be obtained with a simple mechanism, a stable developer concentration can be obtained, and therefore, an electrostatic recording apparatus that is small as a whole and can stably record a high-resolution image can be realized.

[Brief description of the drawings]

FIG. 1 is a perspective view of a stirring device according to the present invention.

FIG. 2 is a schematic cross-sectional view illustrating an entire configuration of an electrostatic recording apparatus including the stirring device of FIG.

FIG. 3 is a sectional view of a developing unit.

FIG. 4 is a detailed view of a recording electrode sheet.

FIG. 5 is an enlarged sectional view of a recording image forming unit U.

FIGS. 6A, 6B and 6C are cross-sectional views of a stirring device.

FIG. 7 is a view showing another rotation method of the stirring device.

FIG. 8 is a diagram showing another configuration example of the stirring device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 paper feed cassette 2 paper feed roller 3 standby roll pair 4 paper transport path 5 cylindrical electrode 5 a bias power supply 6 transfer roll 7 transport belt 8 fixing device 8 a heating roll 8 b pressure roller 9 discharge port 10 discharge tray 12 developing section 13 developing sleeve 13a, 13b, 13c Flat portion 14 Magnet roll 15 Recording electrode sheet 15a Base film 15b Recording electrode wire 16 Scraper plate 17 Circuit element 18 Cover film 20 Toner storage tank 21 Development recording tank 23 Toner supply roll 24 Stirrer 25 Rotating shaft 26 Stirring blade 26a First stirring blade 26b Second stirring blade 27 Cylindrical transport range 28 Cylindrical transport range d Developer d 'Residual developer EL Recording electrode Os Toner supply port P Plain paper t0 Refill toner T Image transfer Unit U Recording image forming unit W Recording unit

Claims (1)

(57) [Claims] 1. A stirrer provided in a container containing a developer and stirring the developer by rotating, the rotary shaft being fixed coaxially at a predetermined angle with respect to the rotary shaft. A first stirring blade having a substantially semicircular cross-sectional shape having a radius R1 and fixedly mounted in the same plane as the first stirring blade in a rotationally symmetric manner with respect to the rotation axis; A second stirring blade having a substantially semicircular cross-sectional shape having a width of R2 and an outer radius of approximately R2, wherein the rotation of the rotating shaft causes the developer to flow through the first stirring blade. Transported in a first direction parallel to the rotation axis,
A stirrer wherein the second stirring blade conveys the toner in a second direction opposite to the first direction.