JP2002278241A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device that is capable of toner replenishment so that appropriate toner concentration can be retained all the time. SOLUTION: In the developing device, a flexible member 14 is stuck to a lower end of a second regulating member 9 in such a manner that the flexible member 14 projects into a toner storage portion 6 along just above a replenishment table 12. In the initial state, a toner replenishment port is completely closed by the flexible member 14. Set positions (positions indicated by reference numerals 8' and 8") of a replenishment stir member 8 are taken into consideration. Thereby, by the time the first toner-replenishment is finished, developer can be circulated to control the toner replenishment. Accordingly, initial overshoot can be restricted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in a developing section of an image forming apparatus such as a copying machine and a laser beam printer, and a process cartridge provided with the developing device.

[0002]

2. Description of the Related Art Conventionally, there has been known a developing device which does not require a toner density detecting means and controls the toner density using a magnetic toner. In these developing devices, the amount of toner taken in is different between a portion where the developer is active and a portion where the developer is not active, or a portion where the amount of the developer is large and a portion where the amount of the developer is small. village
(Black band-shaped density unevenness and wavy density unevenness) are likely to occur.

Therefore, attempts have been made to stabilize the toner density by improving the mechanism of the toner take-in section, thereby realizing a more stable and uniform image density. The attempt will be described with reference to a schematic configuration diagram of a conventional developing device shown in FIG. At the lower end of the developer accommodating section 4, a second developer regulating member 9 is formed in the vicinity of the developer carrier 1 so that the toner concentration of the developer (weight percentage of toner contained in the developer) is within an appropriate range. In some cases, a developer stagnation portion 10 is formed in the toner replenishment path 7, and the developer and the toner do not mix where the toner and the developer are in contact.
Does not take in toner. When the toner is consumed, the bulk of the developer decreases, and the developer stagnation portion 10 decreases, so that the developer circulates below the second developer regulating member 9. When the toner comes into contact with the circulating portion 11, the toner is taken in by the circulating developer and increases in volume.
"0" is formed to interrupt the taking in of the toner. In order to realize such an operation, the pole arrangement and the magnetic force of the developer carrier 1, the position of the second developer regulating member 9, the shape and position of a space for circulating the developer formed on the front side thereof, In addition, the relative positional relationship of the toner supply path and the like are optimized to reduce the density unevenness. Further, the second regulating member 9 has a shape in which the regulating interval at the upstream end in the developer conveying direction of the surface facing the developer carrier 1 is larger than the regulating interval at the downstream end in the developer conveying direction. By doing so, the frictional force between the developer layers is increased immediately before the toner flows into the developer accommodating section 3, and a sufficient amount of charge is imparted to the toner passing therethrough, thereby eliminating the toner having the insufficient charge amount, and Density unevenness is suppressed. Further, the diffusion of the developer circulating unit 11 is suppressed by the surface of the second regulating member 9 facing the developer carrier 1, and the developer in the developer circulating unit 11 is prevented from overflowing to the toner storage unit 6 side. Something has been devised.

[0004]

However, in the above-mentioned prior art, when toner having a high degree of cohesion is supplied to the toner supply path 7, the space between the lower portion of the second regulating member 9 and the toner supply table 12 is provided. Since a toner bridge is formed and toner is not taken in despite the developer circulating section 11 being circulating, there remains a problem that a defective image (white spots or the like) occurs. Further, the surface of the second regulating member 9 facing the developer carrier 1 suppresses the diffusion of the developer in the developer circulating section 11 and prevents the developer from overflowing to the toner storage section 6. However, the countermeasure effect is not sufficient, and when the remaining amount of toner is reduced, the developer overflows into the toner containing section 6 and the toner density increases. Further, when a conventional developing device is mounted on an image forming apparatus, a form in which the developer is preset in another case and set from above or the like immediately before use may be considered.
If the toner is fed by the toner stirring member 8 before the developer reaches the level at which the taking-in of the toner can be controlled, a large amount of toner enters the surface of the developer carrier 1 and the developer accommodating section 3 and is used for a while after the start of use. Has a problem that the toner density becomes higher than an appropriate value (initial overshoot).

In view of the above problems, the present invention provides a developing device capable of replenishing toner so as to always maintain an appropriate toner concentration, and a process cartridge integrally supporting the developing device with a photosensitive member. As an issue.

[0006]

According to a first aspect of the present invention, there is provided a magnetic recording / reproducing apparatus having a magnetic field generating means therein for carrying a two-component developer containing a toner and a magnetic carrier. A developer carrying member to be transported, a first regulating member that regulates an amount of the developer carried and carried by the developer carrying member, and a developer scraped by the first regulating member is housed. A developer accommodating portion, a second regulating member disposed upstream of the first regulating member in the direction of transport of the developer on the developer carrier, and a developer accommodating portion,
A toner container for supplying toner to the developer carrier, wherein the developer blocked by the first regulating member forms a circulating portion upstream of the second regulating member in the developer conveying direction. The developing device is provided with a flexible member having a length that extends into the toner container at the upstream end of the second regulating member in the developer conveying direction. According to a second aspect of the present invention, there is provided the developing device according to the first aspect, wherein a member for causing the flexible member to be flexible is provided in the toner supply and stirring member in the toner storage unit. According to a third aspect of the present invention, there is provided the developing device according to the first aspect, wherein an end of the flexible member on the side of the toner container has a comb shape, a hollow shape, or an uneven shape. According to a fourth aspect of the present invention, there is provided a process cartridge in which the developing device according to any one of the first to third aspects is detachably mountable to an image forming apparatus main body integrally supported together with a photosensitive member.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of the developing device of the present invention. A magnetic field generating means is fixed inside the developer carrier 1, around which the developer carrier 1 is rotatably supported, and a first developer regulating member 2 for regulating the layer thickness of the developer, A developer accommodating case 4 forming a developer accommodating portion 3 for accommodating the developer blocked by one developer regulating member 2 is disposed upstream of the developer regulating member 2. A toner storage section 6 for storing the toner 5 is disposed adjacent to the developer storage case 4, and the toner storage section 6 and the developer storage section 3 are connected by a toner supply path 7. A toner stirring member 8 that feeds the toner toward the supply path 7 while stirring the toner is provided in the toner container 6. A second developer regulating member 9 is formed at the lower end of the developer accommodating case 4 and is close to the developer carrier 1. When the toner concentration of the developer is within an appropriate range, the developer is supplied to the toner replenishing path 7. Forming a stagnation portion 10 of
Where the toner and the developer are in contact with each other, the toner is not taken in because the developer and the toner do not mix. When the toner is consumed, the bulk of the developer decreases, and the developer stagnation portion 10 decreases, so that the developer circulates below the second developer regulating member 9. When the toner comes into contact with the circulation section 11,
When the toner is taken in by the circulating developer and the bulk increases, the developer stagnant portion 10 is formed again to interrupt the taking of the toner.

An example of conditions for realizing the above operation is described below. Magnetic poles are alternately arranged inside the developer carrier 1, P 2 and P 3 are arranged counterclockwise with the magnetic pole facing the image carrier 13 being P 1, and P 4 is located at a position facing the developer accommodating section 3. Place the poles. When the developer circulating section 11 which is the gist of the present invention takes in the toner and reaches a predetermined density,
In order to make the developer stagnation portion 10 appear at the contact portion between the toner and the developer, the arrangement and magnetic force of the P3 and P4 poles, the position of the second developer regulating member 9, and the development formed on the near side thereof It is necessary to optimize the shape and position of the space for circulating the agent and the relative positional relationship of the toner supply path 7. FIG. 2 shows the arrangement diagram obtained based on the experimental results, and the values are shown below. <Mechanical conditions> P3 pole: θ1 = 127 ° Maximum magnetic flux density 61 mT in the direction normal to the developer carrying member P4 pole: θ2 = 36 ° Maximum magnetic flux density 53 mT in the direction normal to the developer carrying member Second developer regulating member angle: θ3 = 14 ° Angle between the vertical surface of the second regulating member facing the developer carrier: θ4 = 24 ° Distance between the second developer regulating member and the surface of the developer carrier: a =
0.6 mm Toner supply path opening width: b = 5.4 mm Developer carrier diameter: c = 16 mm <Developer> Carrier: magnetite or iron 40 to 50 μm Toner: Magnetic substance amount 15 to 40 wt% Silica amount 0.5 to The above operation can be performed under the condition setting of the coverage of the toner of 1.0 wt% to the carrier 50 to 120% Q / M 10 to 30 μC / g or more, and the toner concentration of the developer can be stabilized. These conditions can be combined to reproduce the above operation under different conditions, and the above-mentioned conditions are examples.

In the developing device of the present invention, the upper part of the replenishing table 12 is
It is characterized in that the flexible member 14 is attached in a state of entering the inside. In the initial state, the toner supply port is completely closed by the flexible member 14. In the prior art, when applying to an actual product, a form in which the developer is preset in another case and set from above immediately before use is conceivable, but before the developer reaches a point where the developer can control the toner intake. , Toner stirring member 8
When a large amount of toner enters the surface of the developer carrier 1 or the developer accommodating portion 3 when the toner is fed, the toner concentration becomes higher than an appropriate value for a while after the start of use. Since the toner supply port is initially completely closed by the flexible member 14,
Considering the set position of the toner stirring member 8 (positions 8 'and 8 "), the developer is sufficiently distributed to control the toner supply by the time the first toner supply is performed. Can be suppressed.

The flexible member 14 is lifted upward by an auxiliary mylar 8 "provided on the toner stirring member 8 as the toner stirring member 8 rotates. When the toner is replenished by 8 ', the conventional opening is ensured.
Smooth toner replenishment becomes possible. Once the flexible member 14 is lifted upward, it swings in the supply path 7, so that a toner bridge is not formed between the lower part of the second regulating member 9 and the toner supply table 12.

Further, in the conventional developing device shown in FIG. 5, the developer in the developer circulating portion 11 may move up the back surface of the second regulating member 9 by magnetic force or may overflow into the toner containing portion 6. However, in the present invention, the flexible member 14 holds down the developer, and the circulating portion 1 again
The above-mentioned problem does not occur because the function returns to 1.

FIG. 3 is a diagram showing the shape of the flexible member 14 at the end portion on the toner storage chamber side. 3A shows a comb shape, FIG. 3B shows a hollow shape (mesh shape), and FIG. 3C shows an uneven shape. By setting the shape of the flexible member 14 on the side of the end portion on the toner storage chamber side as shown in (a) to (c), the torque generated when the toner stirring member 8 flips the flexible member 14 is formed. Can be reduced. Further, when the flexible member 14 is repelled by the toner stirring member 8, there is a concern that an aggregate of toner is generated in a region surrounded by the back surface of the second regulating member 9 and the flexible member 14. However, such a concern can be eliminated because the toner slips downward due to the shape as described above.

FIG. 4 is a schematic structural view of a process cartridge which supports the developing device of the present invention integrally with a photosensitive member.
In the drawing, reference numeral 20 denotes the entire process cartridge,
21 is a photoreceptor, 22 is charging means, 23 is developing means, 24
Denotes cleaning means. In the present invention, a plurality of components such as the photoreceptor 21, the charging unit 22, the developing unit 23, and the cleaning unit 24 are integrally connected as a process cartridge. It is configured to be detachable from an image forming apparatus main body such as a printer or a printer. The flexible member 14 is affixed to the lower end of the second regulating member 9 with a double-sided tape or the like. Since the flexible member 14 is repelled many times by the toner stirring member 8, peeling, deformation, etc. occur, and maintenance is required. However, by adopting the process cartridge form, the entire cartridge can be replaced at the time of toner end or developer replacement, so that maintenance work or the like becomes unnecessary.

[0014]

As described above, according to the present invention, the second regulating member is provided at the upstream end thereof in the developer conveying direction with a flexible member having a length that can enter the toner container. A developing device capable of suppressing excessive toner flow to the toner replenishing port and suppressing overflow of the developer into the toner accommodating portion, so that toner can be constantly replenished while maintaining an appropriate toner concentration. In addition, it is possible to provide a process cartridge that supports the photosensitive drum integrally with the photosensitive member.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a developing device of the present invention.

FIG. 2 is a diagram showing an appropriate arrangement of a developing device.

FIG. 3 is a diagram showing a shape of a flexible member at an end portion side of a toner storage chamber.

FIG. 4 is a schematic configuration diagram of a process cartridge in which a developing device of the present invention is supported integrally with a photosensitive member.

FIG. 5 is a schematic configuration diagram of a conventional developing device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 developer carrier 2 first developer regulating member 3 developer containing section 4 developer containing case 5 toner 6 toner containing section 7 toner supply path 8 toner stirring member 9 second developer regulating member 10 developer retaining section DESCRIPTION OF SYMBOLS 11 Developer circulation part 12 Replenishment stand 13 Image carrier 14 Flexible member 20 Process cartridge 21 Photoconductor 22 Charging means 23 Developing means 24 Cleaning means

Claims (4)

[Claims] 1. A developer carrier having a magnetic field generating means therein for carrying and transporting a two-component developer containing a toner and a magnetic carrier, and a developer carrier carried by the developer carrier and transported. A first regulating member for regulating the amount of the developer, a developer accommodating portion for accommodating the developer scraped off by the first regulating member, and a developing device on the developer carrier more than the first regulating member. A second regulating member disposed on the upstream side in the developer conveying direction; and a toner storage unit that is adjacent to the developer storage unit and supplies toner to the developer carrier. A developing device in which the blocked developer forms a circulating section upstream of the second regulating member in the developer transport direction, wherein toner is stored in an upstream end of the second regulating member in the developer transport direction. A flexible member having a length that extends into the unit. Place. 2. The developing device according to claim 1, wherein a member for making the flexible member flexible is provided in the toner supply and stirring member in the toner container. 3. The developing device according to claim 1, wherein an end of the flexible member on the side of the toner container has a comb shape, a hollow shape, or an uneven shape. 4. A process cartridge detachably mountable to an image forming apparatus main body, wherein the developing device according to claim 1 is integrally supported together with a photoreceptor.