JPH0261665A - Multicolor developing device - Google Patents

Abstract

PURPOSE:To reduce the total weight of a developing unit by separating a main hopper for replenishing toner from a developing housing and at the same time using the hopper also as a weight balancer. CONSTITUTION:The developing unit U1 is constituted by juxtaposing plural developing housings A from which the main hopper 28 for replenishing toner is separated in up-and-down direction. The main hopper 28 for replenishing toner to the respective housings A is made into a unit and a hopper unit U2 and the developing unit U1 are connected so that they can freely move up and down contrary. Then, a position control means 38 for making the developing housings A alternately positioned in the developed area of a photosensitive body 3 is also provided. A toner replenishing means 33 is provided by connecting between the toner replenishing port of the hopper 28 for replenishing toner and the toner supplementing port of the developing housing A corresponding to the replenishing port. Moreover, the unit U2 is utilized as the weight balancer. Thus, the total weight of the developing unit U1 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improved technique for a multicolor developing device installed in an image forming apparatus such as an electrostatographic copying machine or a printer.

[Conventional technology]

The above-mentioned multicolor developing device includes at least two developing housings for accommodating developers of different colors,
Therefore, if it is equipped with two developing housings,
If a monochrome superimposed image can be obtained using two different developer colors, and if it is equipped with three developer housings, a full color image can be created by storing yellow, cyan, and magenta developers in each developer housing. can get.

Alternatively, if it is equipped with four developer housings, by storing yellow, cyan, magenta, and black developers in each developer housing, you can create not only full-color images but also vivid black images using only black developer. is obtained.

Among these, for example, a multicolor developing device using four color developers is disclosed in Japanese Patent Application Laid-Open No. 57-204567.

This product consists of four developing housings, each consisting of a developing sleeve built into a developing case with a main toner replenishing hopper, arranged vertically in parallel to form a developing unit. A weight balancer whose weight is approximately equal to the weight of the developing unit is connected to the developing unit so as to be vertically movable, and a position control means is provided for selectively positioning the developing sleeve in the developing area of the photoreceptor.
By storing yellow, cyan, magenta, and blank developers in the toner replenishment hopper of each development housing, the above-mentioned full-color image or a black image using only the black developer can be obtained.

[Problem to be solved by the invention]

According to the above configuration, by balancing the weight balancer with the developing unit, the driving load of the motor can be reduced compared to a configuration in which the developing unit itself is moved up and down, which is advantageous in terms of cost.

However, the above-mentioned developing unit is quite heavy, and by balancing the developing unit with a weight balancer that is equal to y, the overall inertial force is doubled, so that when moving the developing unit up and down, Although the starting torque (and therefore the braking torque) is increased and the driving load on the motor can be reduced compared to the conventional method, it is not possible to expect a significant cost reduction.

Further, since the inertial force becomes large, it is difficult to control the position of the developing unit to stop it at a predetermined position.

The present invention was devised in view of the above-mentioned circumstances, and aims to solve the above-mentioned conventional configuration through extremely rational improvements.

[Means to solve the problem]

In order to achieve the above object, a multicolor developing device according to the present invention has a developing unit configured by vertically arranging a plurality of developing housings each separated from a main toner replenishing hopper. A main toner replenishing hopper is formed into a unit, and the hopper unit and the developing unit are connected to each other so as to be vertically movable;
Position control means for selectively positioning the developing housing in the developing area of the photoreceptor is provided, and the toner replenishing port is positioned between the toner replenishing port of the toner replenishing hopper and the corresponding toner replenishing port of the developing housing. It is characterized by the fact that the supply means are connected in a continuous manner.

[Effect]

According to the above special configuration, the main toner replenishment hopper that does not need to be moved together with the developing sleeve and the developer case is configured separately from the developer housing, and the main toner replenishment hopper unit is configured separately from the developer housing. By using this as a weight balancer, the total weight of the developing unit is reduced, and the overall inertial force of the developing unit and hopper unit is significantly reduced compared to a conventional configuration in which a weight balancer is provided. The driving load of the motor that moves the developing unit up and down is reduced.

Therefore, control to stop the developing unit at a predetermined position is also facilitated.

Since the toner replenishing means is connected in communication with the toner replenishing ports of both units, toner can be replenished to any part of the developing housing.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an electrophotographic copying machine, which is an example of an image forming apparatus, and is configured to be capable of multicolor development. A charging device 4, an exposure section 6 of an exposure optical system 5, a developing device 7, a transfer device 8, a paper separation device 9, and a cleaning device 10 are provided around the cassette case 3. A paper feed conveyance device 12 that conveys the paper inside to the transfer device 8, a paper discharge conveyance device 14 that conveys the paper after transfer and separation to the fixing device 13, and a paper discharge device that discharges the paper after fixing to the tray 15. A pair of rollers 16 is provided.

A paper refeeding section 18 having a double feeding prevention function is provided between the loading section 17 of the cassette case 11 and the paper ejection conveyance device 14.
In addition, a paper refeeding path 19 is provided for selectively ejecting the fixed paper to the paper refeeding section 1, and furthermore, a paper refeeding path 19 is provided for selectively ejecting the fixed paper to the paper refeeding unit 1, A conveyance device that merges and feeds paper to the paper feed conveyance device 12! It consists of 20 parts.

There is a copying mode in which an image is copied on one side of the paper fed from the cassette case 11 and the paper after the single-sided copy is discharged as it is to the tray 15, and the paper refeeding device 1.
The paper stocked in the transfer device 8 after single-sided copying is transferred to the transfer device 8.
The configuration is such that it is possible to select the form of composite copying to be re-fed.

The developing device 7 is provided with a developing unit U+ and a toner replenishing unit (It) which are movable up and down, and in detail, the developing unit U is configured as follows.

That is, as shown in FIG. 2, the developing sleeve 21 ・
A developer stirring device 22 and a return plate 23 are built into the developing case 24, and a sub-hopper 26 equipped with a toner replenishing roller 25 is connected to the upper part of the developing case 24, thereby forming four developing housings A. On the other hand, with the developing sleeve 21 facing the photoconductor 3 and the toner replenishing port a of the sub-hopper 26 facing away from the photoconductor 3, the four developing housings 8 are placed in the unit frame 27. On the other hand, they are arranged in parallel in the vertical direction.

On the other hand, the hopper unit Ut is the developing unit Ut.
The main toner replenishing hoppers 28 for each of the sub-hoppers 26 are arranged horizontally and attached to a hopper frame 29, and each of the toner replenishing hoppers 28 includes:
The toner storage capacity is significantly larger than that of the sub-hopper 26, and a toner feeding helical shaft 30 driven by a motor M1 is provided at the lower side of the toner replenishing hopper 28.

A toner replenishing means 33 comprising a flexible toner feeding helical shaft 31 driven by the helical shaft 30 built into a flexible tube 32 is attached to the toner replenishing hopper 2.
The toner replenishment port 8 is in communication with the toner replenishment port a of the sub-hopper 26.

Each developing case 24 of the developing housing A is provided with a toner concentration detection sensor S that detects the toner concentration inside the developing case 24. Based on the detection information of a decrease in toner concentration from the sensor S, The toner replenishing roller 25 is driven so that the toner in the sub-hopper 26 is replenished into the developing case 24.

Then, when the toner in the sub-hopper 26 is completely consumed and detection information of a decrease in toner concentration is issued from the sensor S in a row, the motor H1 is activated based on this information.
is driven for a predetermined period of time, and a predetermined amount of toner is supplied from the main toner replenishing hopper 28 to the sub hopper 26.

Returning to FIG. 1, two rotating shafts 34.35 whose rotational axes are parallel to the rotational axis of the photoreceptor 3 are provided in the upper space of the developing section 7, and each of the rotating shafts 34.35 is A pulley 36 is provided at a corner at a predetermined interval in the axial direction, and a hanging device 37 such as a wire rope is wound around the pulley 36, and the developing unit U and the hopper unit Uz are attached to both ends of the hanging device 37. The two knits U, U, are connected to each other, so that the two knits U, U, can be moved up and down contrary to each other.

A motor M for raising and lowering the unit is interlocked and connected to one rotating shaft 35 via a speed reduction mechanism (not shown), and the developing sleeve 21 of each developing housing A is connected to the photoconductor 35.
a position control means 38 that is selectively positioned in the development area of
It is linked to the control section 39 of the motor M.

In the above-mentioned developing device 7, the developing case 24 and the sub-hopper 26 of each developing housing A, and the corresponding main toner replenishing hopper 28 are provided with different colors (yellow, cyan, magenta, black). By applying a developer, a monochrome image or a monochrome superimposed image using two different color developers can be obtained, or a full-color image can be obtained using yellow, cyan, and magenta developers.

Here, the toner storage portions (
By configuring the developing unit U and the hopper unit U2 to have a weight balance when the developing case 24, the sub hopper 26, and the main toner replenishing hopper 28) are fully filled with developer. , the drive current of the motor M for raising and lowering the unit can be reduced.

However, due to the toner being consumed on the side of the developer housing A and the toner being replenished from the toner replenishing hopper 28 to the sub-hopper 26, the developing unit U1 and the hopper unit U2 become unbalanced. Since the unbalanced state is worst when the entire amount of toner on the hopper unit Uz side is completely consumed, it is important to equip the motor M that can cope with the load fluctuation at this time. .

By the way, the hopper unit υ2 is the developing unit υ1.
Therefore, it is necessary to increase the toner storage capacity of the hopper unit u2. As a result, it is possible to increase the amount of toner supplied to the main toner replenishing hopper 28 at one time, and to reduce the time and effort required to replenish toner, but from a structural standpoint, it is necessary to increase the toner storage capacity of the hopper unit U2. If this is difficult, it is possible to add a separate weight balancer to the hopper unit U.

〔Effect of the invention〕

As explained above, the present invention has been achieved by focusing on the point that there is no need to move the main toner replenishing hopper together with the developing sleeve and the developing case when the developing unit is moved up and down. The main toner replenishment hopper is separated from the developer housing, and this separated main toner replenishment hopper also serves as a weight balancer, so that the toner replenishment hopper and the toner stored therein are The total weight of the developing housing and thus the developing unit can now be reduced by an amount corresponding to the weight.

Therefore, the inertial force of the entire developing unit and hopper unit can be significantly reduced compared to a conventional configuration in which a weight balancer is provided, thereby reducing the cost of the motor for vertically moving the developing unit. In addition, it has become easier to control the development unit to stop at a predetermined position.

[Brief explanation of the drawing]

FIG. 1 is a schematic longitudinal sectional side view of an electrostatographic copying machine as an example of an image forming apparatus, and FIG. 2 is a partially detailed view of a multicolor developing device. 3... Photoreceptor, 28... Main toner replenishment hopper, 33... Toner replenishment means, 38... Position control means, a... Toner replenishment port, b... Toner replenishment port, A
...Development housing, ul...Development unit, ■!
...Hopper unit. Figure 1 Applicant: Sanda Kogyo Co., Ltd. Agent: Patent attorney Hideo Fujimoto 3...Photoconductor 28...Main toner replenishment topper 33...Toner replenishment means 38...Position control means A...・Developer housing U,...Developer unit U2...Honopa Uninote

Claims (1)

[Claims] A developing unit is constructed by vertically arranging multiple developing housings with separate main toner replenishment hoppers.
The main toner replenishment hopper for each developing housing is formed into a unit, and the hopper unit and the developing unit are connected to each other so as to be vertically movable. The multi-color multicolor apparatus is characterized in that the toner replenishing means is provided with a position control means for positioning the toner replenishing hopper, and the toner replenishing means is provided in communication with the toner replenishing port of the toner replenishing hopper and the corresponding toner replenishing port of the developing housing. Developing device.