JPS59216167A - Dry type developing device - Google Patents

Abstract

PURPOSE:To stir a developer in a circumferential and an axial direction and perform sufficient electrostatic charge by providing transport vanes to the outer circumference of a conveyance impeller for the developer, and providing a screw which rotates in the direction opposite to that of the transport impeller in an impeller shaft. CONSTITUTION:The conveyance impeller 1 which scoops up the developer to a developing roller 10 is provided with radial vanes 5 and transport vanes 6 which transport the developer axially at the outer circumference. Further, an intake 3 and an outlet 4 for the developer and a conveyance screw 7 which rotates in the direction opposite to the conveyance direction of the vanes 6 are provided in a sleeve shaft 2. The developer while stirred in the circumferential direction with the vanes 5 is transported from right to left with the vanes 6 and further transported from left to right in the shaft 2. Consequently, the developer is stirred excellently in the circumferential and axial directions to charge it electrostatically and sufficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a developing device used in a dry electrophotographic apparatus.

(Prior art) A developing device using a two-component developer using radial conveying blades Qt as shown in FIG. Since the action is mainly limited to the circumferential direction, there is a problem that the ability to charge the supplied toner is poor and background smear is likely to occur.Additionally, a separate cross-mixing mechanism is required to stir the developer in the lateral direction. This poses the problem of increasing the size of the device.

On the other hand, the device disclosed in Japanese Patent Application Laid-Open No. 119934/1980 agitates the replenished toner while transferring it from one side to the other using an axial transfer mechanism provided in a conveying impeller. In this apparatus, since the developer stored in the storage layer cannot be transported in the axial direction, there is a problem in that the image density is partially uneven.

(Purpose) The present invention has been made in view of the above problems, and its purpose is to provide a developing device with a simple structure that has not only a circumferential stirring function but also an axial circulation and stirring function. It is about providing.

(Structure) Therefore, details of the present invention will be described below based on illustrated embodiments.

2 and 3 show an embodiment of the present invention,
Reference numeral 1 in the drawing denotes an agitation impeller disposed close to and parallel to the developing roller 10, and around a sleeve-shaped shaft 2, the agitating impeller supplies the developer in the storage tank 12 to the developing roller 10 while agitating it. Radial blades 5 are integrally formed, and the outer periphery of the impeller 1 is surrounded by developer axially transporting blades 6 spirally extending from one end to the other end. 7 is a conveying screw 1 that conveys the developer in the direction opposite to the conveying blade 6 within the sleeve shaft 2 of the conveying impeller 1, which is indicated in ``2''.
A shaft 8 that rotates in the same or opposite direction as the impeller 1 is provided with spiral blades 9, which are supplied with developer that flows in from an inlet 3 provided at one end of the sleeve shaft 2. It is configured to send out the toner toward the outlet 4 at the other end.

In the figure, reference numeral 11 indicates a doctor blade for aligning the ears of the magnetic brush formed on the developing roller 10 to a constant height, 13 indicates a toner tank, 14 indicates a toner supply roller, and 15 indicates a toner tank.
indicate the inflow ports of recycled toner, respectively.

In the embodiment described above, when the transport impeller 1 rotates in the direction of the arrow in the figure, the blades 5 draw up the developer in the storage tank 12 and supply it to the developing roller IO while stirring it in the circumferential direction. On the other hand, along with this rotation, the spiral transfer blade 6 surrounding the outer periphery of the impeller l transfers the developer in the developer tank 12 from right to left in the figure, and cooperates with the transfer blade 5 at the end of the sleeve shaft 2. The developer is guided into the shaft 2 from the inlet 1''3.

In this embodiment, a toner tank 13 is provided above the inlet 3, and toner is supplied to the inlet 3 from a toner supply roller 14 provided at the opening end of the toner tank 13 in accordance with an output signal from a toner concentration sensor. Because it is configured,
The conveyance screw 7 rotating within the sleeve shaft 2 stirs and mixes the developer that has flowed into the inflow port 3 and the replenished toner, while moving it in the opposite direction to the conveyance direction by the conveyance blade 6, that is, toward the right end in the figure. The developer is transported toward the open outlet 4, and then supplied to the developing roller 10 while being circulated in the axial direction by the transport blades 6 and the transport screw 7 from left to right and right to left. .

Note that the above is an explanation of a type in which toner is replenished to one end of the storage tank 12;
Similar agitation and mixing can be performed using an apparatus that replenishes almost the entire width of the container.

(Effects) As explained above, according to the present invention, since the blades for transporting the developer in the axial direction are provided on the outer periphery of the impeller for supplying the developer, these two blades transport the developer in the circumferential direction and the axial direction. In addition, the hollow shaft is provided with an inflow amount of developer of 1" and an outflow opening, and a member for transporting the developer in the direction opposite to the transport blade is installed in the shaft. With this provision, it becomes possible to circulate the developing agent in the axial direction within the developer tank, and it is possible to ensure uniform density image formation. Furthermore, what is noteworthy is that the stirring and circulation can be performed only by the impeller, so that the developing device can be significantly downsized.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing an example of a conventional device, FIG. 2 is a block diagram of a device showing an embodiment of the present invention, and FIG. 3 is a side view of a conveying impeller. ■...Conveyance impeller, 2...Sleeve shaft 3...
・Inflow port, 4...Outlet port, 5...Transportation blade 6・
...Transfer vane, 7...Transfer screw 10...
・Developing roller applicant: Ricoh Co., Ltd. Agent Patent attorney: Kei Nishikawa Figure 3

Claims (1)

[Claims] A hollow rotary shaft disposed parallel to and close to the developing roller is provided with an inflow opening and an outflow amount 1'' for the developer at intervals, and radial blades are provided on the circumference of the shaft for supplying the developer to the developing roller. further provided with transfer blades for transferring the developer in the axial direction on its outer periphery, and a rotary transfer member for transferring the developer in a direction opposite to the transfer direction of the transfer blades within the hollow rotating shaft. A dry developing device featuring: