JPS61151576A - Developing device - Google Patents

Abstract

PURPOSE:To switch developing devices automatically in accordance with the state of a developer to reduce the number of times of toner supply by providing the first detecting means which detects the classification of each developing device and a control means which controls switching among developing devices in accordance with the output of the second means which detects the state of the developer in each developing device. CONSTITUTION:When a developing device comes to a position facing a sensor part 31 of a toner remainder detecting means 30, it is detected whether there is a toner in a hopper of the developing device or not. If a CPU discriminates 'toner presence' because a photodetector 33 does not receive light, a normal copy sequence is executed; but if the CPU discriminates 'toner absence' by the light reception detection signal of the photodetector 33, the classification of the developing device placed in the remainder detection position at present is detected. At this time, the position is detected by a stop position detecting means 20, and the classification is detected by a developing device classification detecting means 17. Next, the CPU discriminates whether there is a developing device which is in the same classification as the developing device placed in the remainder detection position and has a lower priority level or not.

Description

[Detailed description of the invention] [Technical details] The present invention is applicable to multi-color (two or three or more monochromatic colors) or full-color electrophotographic copying machines, computers,
The present invention relates to a developing device used in an image forming apparatus typified by a color recording device that constitutes an output section of a facsimile machine or the like.

[Conventional technology]

For example, in a configuration in which a plurality of developing devices using toners of different colors are arranged on a single latent image carrier such as a photosensitive drum, a plurality of developing devices are arranged sequentially around the circumference of the latent image carrier. and a plurality of developing units supported by a rotating body,
It has been proposed that by rotationally driving this rotating body, only the developing device corresponding to the desired color toner is opposed to the latent image carrier.

Particularly in the latter case, since one developing device always faces the latent image carrier, the length of the latent image carrier can be made as small as possible.

By the way, in a developing device equipped with multiple developing devices,
For example, when copying a large amount of two- or three-color single-color copies, and when one color is used particularly frequently, it is a hassle to have to stop copying and replenish only that toner. there were.

[Purpose of the invention]

This invention has been made in view of the above points, and by providing a developing device that can automatically switch according to the state of the developer when a plurality of developing devices of the same type are installed, it is possible to remove toner. The purpose is to reduce the number of replenishments.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 shows an example of a color copying apparatus to which the present invention is applied.

In the figure, a photosensitive drum 1, which is a latent image carrier, rotates in the direction of the arrow. A charger 21, a light optical system 3, a developing device 4, a transfer system 5, and a cleaning device 6 are arranged around it. The optical system 3 includes a document scanning section 3a and a color separation filter portion 3b. The developing device 4 includes a yellow developer 4Y using yellow toner, a magenta developer 4M using magenta toner, and a cyan ring [f] using cyan toner.
4C.

A black developing device 48k using black toner is integrally provided. Each developing device is manufactured by the applicant in the Japanese Patent Publication No. 55-2.
As disclosed in Publication No. 0579, magnet roller R
The toner is prevented from scattering by the action of a magnetic field, and as shown in the figure, the developing device is detachably held on a rotating body 4a and rotated about a central axis 4b, thereby allowing the developing device to be replaced with respect to the developing position.

Note that S is a toner stirring screw.

On the other hand, the transfer section 5 includes a drum 5b having a gripper 5a,
It has a transfer discharger 5C inside thereof. A color image is formed by sequentially transferring color toner onto a transfer material supported on the transfer drum. This transfer material is supplied from a cassette (cassette) 7, and the transfer material that has completed the transfer process is separated by a separation means 8, and reaches onto a tray 10 via a fixing device 9.

FIG. 2 is a perspective view showing the main parts of the developing device ff14.

In the figure, reference numeral 11 denotes a disk-shaped rear plate that is provided at the rear end of the rotating body 4a and has a gear 11a around its periphery.

12 is a servo motor for driving a rotating body, and its output shaft 12a
A gear 13 fixed to one end of the rotary body is connected to the aforementioned rotating body outer layer gear 11a via a gear 14. The illustrated rotating body 4
In a, there are two yellow developers 4Y1 and 4Y2, one magenta developer 4M, and one cyan developer 4C.
It is equipped with a three-color copy mode,
Of these, the cyan developing device 4C is shown in a state in the middle of installation.

Reference numeral 15a denotes a developing device type detection sensor 7 for detecting the type of the developing device (that is, the toner color of the developing device), and is fixed to the rear plate 11 of the rotating body 4a. Reference numeral 16a denotes a reflecting plate provided on the end face of the developing device at a position opposite to the photosensor 15a. The seven-point sensor 15a and the reflective plate 16a are provided in pairs for each of the developing devices 4C, 4Y1, 4Y2, and 4M, and constitute a developing device type detection means 17.

Each of the reflectors 168 to 16d has its own reflectance, and each of the seven sensors 158 to 15d outputs a signal with a different voltage level depending on the amount of reflected light.

Reference numeral 20 indicates an example of a stop position 1ff (development position) detection means of the rotating body 4a, which includes a reflecting plate 21 fixed to the end of the central axis 4b of the rotating body 4a so as to be integrally rotatable; It is provided with seven sensors 22a, 22b, and 22C122d which are arranged and fixed to the main body side.

31 is a toner remaining amount detection means 3 in the developing device shown in FIG.
0, which is provided outside the developing device 4.

In FIG. 3, 32 is a light source, and 33 is a light receiving element.

34. 35 is an optical fiber arranged with a gap ga inside the developing device (4Y, 4M, 4C...), 36 is a collective lens, and if toner exists in the gap ga,
The light velocity A from the light source 32 is absorbed by the toner and passes through the light receiving element 33.
However, if there is no toner, the light speed i is detected by the light receiving element 33 via the optical fiber 32 and collective lens 36, and a toner-absent signal is output.

FIG. 4 is a block diagram of the control circuit of the developing device of this embodiment. In the figure, 40 is a sequence controller (CPU) that controls the entire image forming apparatus, 41 is an operation and display unit provided with keys for operating and displaying the image forming apparatus, and 42 is a memory in which an image forming program is stored in advance. Ru. Each signal for controlling the operation of the developing device 4, that is, the signals from the remaining toner detection sensor 31, the developing device type detection sensors 15a to 15d1, and the rotary body stop position detection sensors 22a to 22d (photosensors) are input to the input interface. 7 Ace 43, CPU 4 via I10 boat 44
0, and the command from the CPU 40 is sent to the load drive circuit 45 to control the drive motor 12 of the developing device 4.

Next, the control action of the developing device will be explained with reference to chart 70 in FIG.

First, the type of developing device mounted in the rotating body 4a (in this embodiment, two yellow 4Y, one magenta 4M, and one cyan 4C) is detected by a signal from the developing device type detection means 17 (step 1). ).

Next, from the above type detection signal, set the priority to the same type (2 4T) developers (4Y1 and 4Y2).
Thereafter, the developing device 4Y1 with the highest priority is used for development (step 2).

The presence or absence of toner in the hopper of the developing device is detected when the developing device comes to a position opposite to the sensor section 31 of the remaining toner amount detecting means 30 (step 3).

Since the CPU 40 does not receive light to the light receiving element 33,
If it is determined that "toner is present", the normal copy sequence is executed, but the light reception detection signal of the light receiving element 33 indicates that "toner is present".
If it is determined that there is no toner (step 4), the type of developing device currently located at the remaining sheet detection position is detected. At this time, position detection is performed by the stop position detection means 20, and type detection is performed by the developing device type detection means 17 (step 5).

Next, the CPU 40 determines whether there is a developing device of the same type (same color toner) as the developing device located at this remaining amount detection position and with a lower priority level (step 6).

As a result, if it is determined that there is no developing device of the same type, copying will continue for the sheet currently being copied, and after the copying is completed, the copying machine will be turned off without executing the next copying process. Stop. On the other hand, the same type of developing device "Yes" (
For example, if it is determined that 4Y1, 4Y2). Among the developing devices of the same type, the one with the next priority (4Y2) is selected (step 7).

Thereafter, the developing process is repeated using this preferentially selected developing device (step 8).

The above series of operations can be similarly applied to other developing devices than yellow.

In this embodiment, the switching of the developing device is determined based on the toner set amount detection signal. It is also possible to switch to a developing device of the same type. Furthermore, the present invention is not limited to rotary developing devices, and can be similarly applied to fixed developing devices arranged in parallel around the circumference of the photosensitive drum 1, or to developing devices that combine both types. be.

〔Effect of the invention〕

As explained above, according to the present invention, the type of developing device is detected, and if multiple developing devices of the same type are installed, the system automatically Since the developing device is changed over, it is possible to reduce the effort required to replenish developer during a copying operation and to improve copying efficiency.

[Brief explanation of drawings]

1 to 5 show an embodiment of the present invention, and FIG. 1 is a side sectional view of an image forming apparatus equipped with a rotary multicolor developing device;
FIG. 2 is a perspective view of the main parts of the developing device, FIG. 3 is a diagram explaining the function of the remaining toner amount detection means, FIG. 4 is a block diagram of the control circuit, and FIG. 5 is a flowchart. 4Y, 4C, 4M, 48k...Developer 4...
...Developing device 1T...Developing device type detection means 20...Rotating body stop position detection means 40...
...Control device Fig. 2 3o Fig. 3

Claims (3)

[Claims] (1) Multiple developing devices and a first device that detects the type of each developing device.
The present invention includes a detection means, a second detection means for detecting the state of the developer in each developing device, and a control means for switching and controlling the developing devices according to the outputs of the first detection means and the second detection means. Characteristic developing device. (2) The control means detects that the first developing device and the second developing device are of the same type, and further detects that the first developing device is in a developer-free state and the second developing device is The developing device according to claim 1, wherein the first developing device is switched to the second developing device when the second detecting means detects that the developing device is in a developer-filled state. . (3) The first aspect of the present invention is characterized in that a priority order for the switching control is set for the plurality of developing devices.
Developing device described in Section 1.