JP2003280380A - Developing device and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stable and uniform developing device by integrating parts around a developer storage chamber so that the addition tolerance of parts is reduced to enhance accuracy, and to provide a process cartridge and an image forming apparatus. <P>SOLUTION: The developing device 14 self-controlling toner concentration is constituted of the developer storage chamber 30 where a 1st regulator part 17, a developer storage part 16 and a 2nd regulator part 23 are integrally formed, and a developing lower member 31 forming the end wall surfaces of the 1st regulator part 17, the developer storage part 16 and the 2nd regulator part 23. The process cartridge 101 and the image forming apparatus 100 use the developing device 14. <P>COPYRIGHT: (C)2004,JPO

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 as a developer for developing an electrostatic charge image in electrophotography, electrostatic recording, electrostatic printing, etc., and a process cartridge using this developing device. , An image forming apparatus. More specifically, the present invention relates to a copying machine using a direct or indirect electrophotographic developing system, a laser printer, a process cartridge using a developing device used for plain paper fax, and an image forming apparatus.

[0002]

BACKGROUND OF THE INVENTION Electrophotography generally utilizes a photoconductive material to form an electrical latent image on an electrostatic latent image carrier by various means and then the latent image is formed using toner. After development and transfer of toner to paper or the like as required, the toner is fixed by heating or solvent vapor to obtain a copy image or a print image. As a means for developing an electrostatic latent image formed on an electrostatic latent image carrier such as a photoconductor, a method using a liquid developer (wet development method) and a method in which a colorant is dispersed in a binder resin are used. Or a method using a one-component or two-component dry developer in which the toner is mixed with a carrier (dry development method). Although each of these methods has advantages and disadvantages, at present, the dry development method is widely used. Among these methods, the two-component developing method is relatively widespread, centering on medium- to high-speed copying machines and printers, because it can achieve relatively high speed and long life compared to the single-component developing method. is doing.

Conventionally, in the two-component developing system in which the toner concentration is self-controlled by the two developer regulating portions and the developer carrying member, a sensor and a toner supply control device are not required, and a low cost can be realized. Can be made smaller. However, due to the structure that cannot be forcibly controlled from the outside, the toner concentration control depends on the gap between the regulation portion and the developer carrier and the magnetic flux density of the developer carrier by the magnetic field generating means. Therefore, the developer regulation amount is biased due to variations in assembly of the regulation gap between the first regulation unit and the second regulation unit, manufacturing component tolerances, deviations in the magnetic flux density distribution of the magnetic field generating means of the developer carrier, and the like. The developer is biased with respect to the axial direction of the developer carrying member (the wall surface of the developer containing chamber end). Further, if the developer accommodating member is made of resin or the like, it is difficult to secure the rigidity, so that the deviation from the gap with the regulation portion may occur due to the influence of warpage. Due to these, toner density deviation occurs.

Therefore, this system requires high precision of parts and assembling, and if these are not satisfied, abnormal images such as uneven image density and background stain are caused. When the first regulation unit, the second regulation unit, and the developer accommodating unit are separate bodies, the variations in the precision of these parts and the variations due to assembly are accumulated, which affects the toner concentration control and causes uneven toner concentration. There is a problem of causing the abnormal image mentioned above.

[0005]

SUMMARY OF THE INVENTION Therefore, the present invention has been made in view of the above problems, and reduces the stacking tolerance of parts by integrating the parts around the developer accommodating chamber to improve accuracy. An object of the present invention is to provide a stable and uniform developing device, a process cartridge, and an image forming apparatus by increasing the height. Another object of the present invention is to provide a developing device, a process cartridge, and an image forming apparatus that are free from background stains and have excellent black solid density uniformity because the gap between the regulation section and the developer carrying member can be varied. Another object of the present invention is to provide a developing device, a process cartridge and an image forming device which are excellent in recyclability and have a simple structure that can be easily assembled and disassembled by integrating parts around the developer accommodating chamber. .

[0006]

In order to achieve the above-mentioned object, the invention according to claim 1 has a magnetic field generating means inside, a magnetic toner comprising at least a binder resin and a magnetic material, and at least a magnetic material. A developer carrier that carries and conveys a two-component developer consisting of a magnetic carrier, a first regulation unit that regulates the amount of the developer carried and conveyed by the developer carrier, and a first regulation unit. The developer accommodating portion for accommodating the developer scraped off by the developer accommodating portion, and the toner accommodating portion adjacent to the developer accommodating portion for supplying the toner to the developer accommodating member are provided. A developing device for changing a contact state between a developer and a toner according to a change in toner concentration to change a toner taking-in state of the developer on a developer carrying member, wherein the developer accommodating portion includes a first regulating portion. Transport of developer on developer carrier rather than The second regulating portion is provided on the improved flow side, and the second regulating portion prevents the developer from being discharged when the toner concentration of the developer on the developer carrier increases and the layer thickness of the developer increases. In a developing device in which a gap with a developer carrying member is set in order to regulate the passage of the increased amount, the developing device is a developer in which a first regulating portion, a developer accommodating portion, and a second regulating portion are integrally formed. The developing device includes an accommodating member, a first restricting portion, a developer accommodating portion, and a lower developing member that forms an end wall surface of the second restricting portion. According to a second aspect of the present invention, in the developing device according to the first aspect, the developing device is a developing device in which the developer accommodating member and the developing lower member are made of a non-magnetic material.
According to a third aspect of the present invention, in the developing device according to the first or second aspect, the developing device forms a gap between the developer carrying member and the first restricting portion and the second restricting portion from the outside of the developing device. Adjustable developing device.

According to a fourth aspect of the present invention, there is provided a process cartridge which integrally supports a developing device and at least one selected from a photoconductor, a charging means, and a cleaning means, and is detachable from a main body of an image forming apparatus. The device is
A process cartridge is the developing device according to any one of claims 1 to 3. The invention according to claim 5 is
At least an image forming apparatus for forming an image on a recording sheet, comprising: a photoconductor for forming an electrostatic latent image; a developing device for developing the electrostatic latent image on the photoconductor; and a developing device. The image forming apparatus is the developing apparatus described in any one of 1 to 3.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of a developing device portion of an image forming apparatus showing an embodiment of the present invention. The developing device 13 disposed on the side of the photosensitive drum 1 serving as a latent image carrier includes a support case 14, a developing sleeve 15 serving as a developer carrier, a first restricting portion 17, a second restricting portion 23, and a developing device. The agent container 16 is mainly configured by a side wall (not shown) and the like. The support case 14 having an opening on the side of the photosensitive drum 1 forms a toner hopper 19 as a toner storage portion for storing the toner 18 therein. A developer accommodating member 30 forming a developer accommodating portion 16 accommodating a developer 22 composed of the toner 18 and a carrier of magnetic particles is provided near the photosensitive drum 1 side of the toner hopper 19.
It is provided integrally with the support case 14. The developer accommodating member 30 is configured to integrally form the first restricting portion 17, the second restricting portion 23, and the developer accommodating portion 16. As a result, when assembled as a developing device, it is possible to reduce the deviation in the longitudinal direction between the first and second restricting portions 17 and 23 and the developing sleeve 15. Further, by reducing this deviation, it is possible to reduce the deviation of the developer amount in the developer accommodating portion 16, and further to reduce the deviation of the toner concentration of the developer 22.

Further, the support case 14 located below the developer accommodating portion 16 has a projecting portion 14 having a facing surface 14b.
a is formed, and a space between the lower surface of the developer accommodating portion 16 and the facing surface 14b forms a toner supply opening 20 for supplying the toner 18. Inside the toner hopper 19, a toner agitator 21 as a toner supply unit that is rotated by a driving unit (not shown).
Is provided. The toner agitator 21 sends the toner 18 in the toner hopper 19 toward the toner supply opening 20 while stirring. A developing sleeve 15 is arranged in the space between the photosensitive drum 1 and the toner hopper 19. The developing sleeve 15, which is rotationally driven in the direction of the arrow in the figure by a driving unit (not shown), has a magnet (not shown) serving as a magnetic field generating unit in which the relative position of the magnetic pole is fixed with respect to the developing device 13. There is.

A first restricting portion is provided on the side of the developer accommodating portion 16 facing the side attached to the support case 14. The first restricting portion 17 is arranged in a state where a constant gap is maintained between the tip of the first regulating portion 17 and the outer peripheral surface of the developing sleeve 15. A second restricting portion 23 as a restricting portion is provided at a portion of the developer accommodating portion 16 located near the toner supply opening 20. The second restricting portion 23 is arranged such that its free end maintains a constant gap with respect to the outer peripheral surface of the developing sleeve 15. The developer accommodating portion 16 is configured to have a sufficient space for circulating and moving the developer 22 within a range where the magnetic force of the developing sleeve 15 is exerted. The facing surface 14
b is formed over a predetermined length so as to incline downward from the toner hopper 19 side toward the developing sleeve 15 side. As a result, when vibration, uneven magnetic force distribution of a magnet (not shown) provided inside the developing sleeve 15, partial increase in toner concentration in the developer 22, and the like occur, the second restricting portion 23 and the developing sleeve 15 are caused. Even if the carrier in the developer accommodating portion 16 falls from between the peripheral surface of the developing sleeve 1 and the peripheral surface of the developing sleeve 1, the dropped carrier is received by the facing surface 14b.
It is moved to the 5 side, magnetically attached to the developing sleeve 15 by magnetic force, and supplied again into the developer accommodating portion 16. As a result, it is possible to prevent a decrease in the amount of carriers in the developer accommodating portion 16, and it is possible to prevent occurrence of uneven image density in the axial direction of the developing sleeve 15 during image formation. The inclination angle α of the facing surface 14b is about 5 °, and the predetermined length 1 is preferably 2 to 20 mm, more preferably 3 to 10 mm.

With the above structure, the toner 18 sent out from the inside of the toner hopper 19 by the toner agitator 21 is supplied to the developer 22 carried on the developing sleeve 15 through the toner supply opening 20, and the developer accommodating portion. Transported to 16. The developer 22 in the developer accommodating portion 16 is carried on the developing sleeve 15 so that the photosensitive drum 1
The toner 18 is conveyed to a position facing the outer peripheral surface, and only the toner 18 is electrostatically coupled with the electrostatic latent image formed on the photoconductor drum 1 to form a toner image on the photoconductor drum 1. . The developer accommodating member 30 is integrally formed, and the end wall surface thereof, that is, the longitudinal end of the developer accommodating member 30 has a separate wall surface. The structure is shown in FIG.
The end wall surface 31a of the developer accommodating chamber is connected to the lower end member 31b of the developing section, and a developing lower member 31 having an integral structure is formed. The developer accommodating member 30, the developing lower member 31, and FIG.
The developing device 13 is configured by combining the developing sleeve 15 not shown in FIG. 1 with the structure shown in FIG.

In the structure of the developer accommodating member 30 in which the first restricting portion 17, the second restricting portion 23, and the developer accommodating portion 16 are integrally formed, the restricting portions such as the first restricting portion 17 and the developing sleeve 15 are formed. It does not have a mechanism to adjust each gap. Further, when the developer accommodating member 30 is moved for adjustment,
A gap is generated between the support case 14 and the developing lower member 31,
The developer 22 may leak out. Further, it is important for the developer 22 that the toner concentration is stable over time, and particularly in the self-toner concentration control system. Therefore, in order to adjust the gap between the first regulating portion 17 and the developing sleeve 15 which is important for controlling the toner density, the developing sleeve 1
A mechanism for moving the 5 side was used. Its structure is shown in FIG. The developing sleeve bearing 40 is disposed in a movable portion inside the movable member 42, and the developing sleeve bearing 40 is laterally positioned by the spring 43 and the lateral position adjusting bolt 45 depending on the tightened state of the lateral position adjusting bolt 45. . In addition, the movable member 4
2 is arranged inside the movable member 41, and the position in the vertical direction is determined by the tightened state of the vertical position adjusting bolt 46 by the spring 44 and the vertical position adjusting bolt 46. The two-dimensional positional relationship can be adjusted by these movable mechanisms.

FIG. 4 shows a developer accommodating member 30 and a developing lower agent 1.
4 and the movable mechanism of the developing sleeve bearing 40 are combined to constitute the developing device 13. The gap between the developing sleeve 15 and the first and second restricting portions 17 and 23 is adjusted by moving the developing sleeve bearing 40 by a vertical position adjusting bolt 46 and a horizontal position adjusting bolt 45, respectively.
Further, in the present method of self-toner concentration control, the toner concentration can be changed by changing the gap between the first and second regulating portions 17 and 23 and the developing sleeve 15. The developer accommodating member 30 and the developing lower member 14 are both non-magnetic materials. Since the developer 22 uses a magnetic carrier in the developer 22, if the developer accommodating member 30 has magnetism, it hinders the movement of the developer 22. By making the developer accommodating member 30 and the developing lower member 31 non-magnetic, the developer 2
It is possible to make the movement of 2 uniform and reduce the deviation of the toner density.

Further, the above-mentioned developing means is integrally formed as a process cartridge 101, and the process cartridge 101 is detachably attached to the main body of the image forming apparatus 100 such as a copying machine or a printer. The configuration is shown in FIG. The image forming apparatus 100 includes a charging unit 105,
Developing means 106, photoconductor 107, cleaning means 10
It consists of eight. In the image forming apparatus 100 in which the process cartridge 101 using the developing unit 106 which is the developing device of the present invention can be mounted, the photosensitive drum 107 is rotationally driven at a predetermined peripheral speed. In the course of rotation, the photosensitive drum 107 is subjected to uniform charging at a predetermined positive or negative potential on its peripheral surface by the charging means 105, and then is subjected to image exposure light from image exposure means such as slit exposure or laser beam scanning exposure. As a result, an electrostatic latent image is sequentially formed on the peripheral surface of the photosensitive drum, and the formed electrostatic latent image is then developed by the developing unit 10.
6, the toner image is developed by the toner 6, and the developed toner image is transferred to the transfer material fed from the paper feeding section between the photosensitive drum 107 and the transfer means 109 in synchronization with the rotation of the photosensitive drum 107. Are sequentially transferred by. The transfer material that has received the image transfer is separated from the surface of the photosensitive drum 107, is introduced into the image fixing means 110, and the image is fixed, and is printed out of the apparatus as a copy. The surface of the photosensitive drum 107 after the image transfer is cleaned by the cleaning unit 10.
The residual toner after transfer is removed by 8 to make the surface clean, and after the charge is removed, it is repeatedly used for image formation.

[0015]

EXAMPLES The present invention will be specifically described below with reference to examples. (First Embodiment) Non-magnetic aluminum is used for the developer accommodating portion, and the one prepared by extrusion molding is used. A polycarbonate material was used for the under development member. In FIG. 6, “integrally formed” means a developing device using the developer accommodating portion of the present invention, and “separate body” means a developing device in which the conventional regulating portion and the developer accommodating portion are separate units. The left end of the development area indicates the position of the left end to be printed. FIG. 6 shows the result of measurement of the distribution of DG1 in the longitudinal direction of the developing unit, which is formed separately from the developer accommodating unit formed integrally with the related art. Moreover, the result of the distribution measurement of DG2 is shown in FIG. Here, the case where the predetermined target value is the same as the target value is set as 1.00 and standardized. At this time, the toner concentration distribution in the longitudinal direction of the developing section, which is self-controlled in the developing apparatus described above, was measured and compared with that of the conventional developing apparatus in which the regulating section and the developer accommodating chamber are separate bodies. The result is shown in FIG.

As can be seen from FIG. 6 and FIG. 7, since the separate one has a low rigidity, the standard value is almost 1.00 for some parts, but the other part has a standard value of 0.90 or less. There is also a part. However, in the case of a developing device that is integrally formed, the standard value is 1.0
It is close to 0. Further, in FIG. 8, in the developing device formed integrally, the toner concentration is almost the same throughout, but in the developing device formed separately, the difference in the total toner concentration is large. ing.

(Second Embodiment) An integrally formed developer accommodating member of the present invention is printed in an equilibrium state by printing a pattern with an image area ratio of 5% using a non-magnetic aluminum material and a magnetic carbon steel SECC material. The results of comparing the toner densities are shown in FIG. The regulation gaps DG1 and DG2 and the developing sleeve were under the same conditions. From FIG. 9, the toner concentration is almost the same throughout the developing device made of the non-magnetic aluminum material. Furthermore, the target toner density is 8
It is almost kept at%. In the magnetic SECC material developing device, the toner concentration is almost the same throughout, but the target toner concentration of 8% is not maintained. Similar results were obtained when austenitic stainless steels such as SUS304 and SUS316 were used as the non-magnetic member.

[0018]

As described above, in the developing device of the present invention, by integrally forming the two restricting portions and the developer accommodating portion, the rigidity of the restricting portion can be increased, and the restricting portion and the developing sleeve can be formed. By eliminating the deviation in the longitudinal direction of the air gap, the developer distribution in the developer storage chamber can be made uniform, and the toner density can be made uniform, so that an image with uniform image density and uniform image density can be obtained. There is an effect. Further, in the developing device of the present invention, it is possible to control the toner concentration from the outside in the developing device using the self-toner concentration control, and there is an excellent effect that an image with less unevenness in image density and scumming can be obtained. Further, in the developing device of the present invention, by integrally forming the two regulating portions and the developer accommodating portion, the number of parts can be reduced, the disassembling and assembling can be easily performed, and the recyclability can be improved.

[Brief description of drawings]

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

FIG. 2 is a schematic view showing a structure of a developer accommodating member and a developing lower member which constitute the developing device of the present invention.

FIG. 3 is a schematic view showing the structure of a developing sleeve bearing position moving mechanism used in the developing device of the present invention.

FIG. 4 is a developer accommodating member that constitutes the developing device of the present invention.
FIG. 3 is a schematic view showing the structures of a developing lower member and a developing sleeve bearing position moving mechanism.

FIG. 5 is a schematic diagram showing a configuration of an image forming apparatus of the present invention.

FIG. 6 is a first view formed by a developing device formed separately from the developing device of the present invention configured as an integrally formed developer accommodating member.
It is a graph which compares and shows the gap distribution of a control part.

FIG. 7 is a second view formed by a developing device formed separately from the developing device of the present invention configured as an integrally formed developer accommodating member.
It is a graph which compares and shows the gap distribution of a control part.

FIG. 8 is a graph showing a comparison of axial toner density distributions by a developing device of the present invention configured as an integrally formed developer accommodating member and a developing device configured as a separate member.

FIG. 9 is a graph showing a comparison of toner concentration distributions in the axial direction of a developing device formed separately from the developing device of the present invention, which is made of a developer accommodating member material.

[Explanation of symbols]

1,107 Image carrier (photosensitive drum) 13 Development device 14 Support case 14a protrusion 14b facing surface 15 Developer support (development sleeve) 16 Developer Storage 17 1st restriction section (1st restriction section) 18 toner 19 Toner Hopper 20 Toner supply opening 21 Toner Agitator 22 Developer 23 2nd regulation part (2nd regulation part) 40 Development sleeve bearing 41, 42 movable member 43,44 spring 45 Horizontal position adjustment bolt 46 Vertical position adjustment bolt 100 image forming apparatus 101 process cartridge 105 charging means 106 developing means 108 cleaning means

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/09 G03G 15/08 507Z F term (reference) 2H031 AA01 AA12 AB03 AB09 AC08 AC17 AC30 AC33 AC34 AD03 BA05 BA09 BC00 DA01 EA03 FA05 2H077 AA12 AA16 AA20 AB03 AB13 AD02 AD06 AD17 AD18 BA08 BA09 DA10 DB14 EA01 FA16 FA19

Claims (5)

[Claims] 1. A developer carrying member which has a magnetic field generating means inside and carries and conveys a two-component developer consisting of a magnetic toner composed of at least a binder resin and a magnetic material and a magnetic carrier composed of at least a magnetic material. A first regulation part for regulating the amount of the developer carried and carried by the developer carrier, a developer accommodating part for accommodating the developer scraped off by the first restricting part, and a developer accommodating part. Adjacent to this, a toner accommodating portion that supplies toner to the developer carrying member is provided, and the contact state between the developer and the toner is changed according to the change in the toner concentration of the developer on the developer carrying member. A developing device for changing a toner taking-in state of a developer on a carrier, wherein the developer accommodating section is arranged upstream of a first regulation section in the developer carrying direction of the developer. 2 regulating section, and the 2nd regulating section bears the developer. In a developing device in which a gap between the developer carrier and the developer carrier is set in order to restrict passage of the increased developer when the toner concentration of the developer on the carrier increases and the layer thickness of the developer increases. The developing device forms a developer accommodating member integrally formed with a first restricting portion, a developer accommodating portion, and a second restricting portion, and an end wall surface of the first restricting portion, the developer accommodating portion, and the second restricting portion. And a developing lower member for performing development. 2. The developing device according to claim 1, wherein the developer accommodating member and the developing lower member are made of a non-magnetic material. 3. The developing device according to claim 1, wherein the developing device is capable of adjusting a gap between the developer carrier and the first restricting portion, the second restricting portion, from the outside of the developing device. And developing device. 4. A process cartridge, which integrally supports a developing device and at least one selected from a photoconductor, a charging unit, and a cleaning unit, and which is detachable from the main body of the image forming apparatus, wherein the developing unit is any one of claims 1 to 3. 3. The process cartridge according to any one of 3 above. 5. An image forming apparatus for forming an image on a recording medium, comprising at least a photoconductor for forming an electrostatic latent image, a developing device for developing the electrostatic latent image on the photoconductor, and a developing device. An image forming apparatus, wherein the developing device is the developing device according to any one of claims 1 to 3.