JPS6275569A - Developing device - Google Patents

Abstract

PURPOSE:To apply toner with always stable prescribed density to an electrostatic latent image formed on the surface of a photosensitive body by ending the detection of toner concentration after the passage of a prescribed time from the end of application of toner to the electrostatic latent image formed on the photosensitive body by a toner applying means. CONSTITUTION:Whether a fixed time (5sec e.g.) required until a developer is sufficiently agitated by an agitation blade 5 has elapsed or not is decided and whether a toner feeding request exists or not is decided on the basis of detection by a toner concentration detecting sensor 4. Then, a toner solenoid 15 is turned on and the toner is fed. After the passage of the fixed period until the developer is sufficiently agitated by the agitation blade 5, toner concentration is detected by the sensor 4. Since the toner concentration can be detected after stabilizing the concentration, the toner concentration can be precisely detected by the sensor 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a developing device that forms a toner image on an electrostatic latent image formed on a photosensitive drum of a copying device, for example.

[Technical Background of the Invention and Problems Thereof] Conventionally, as a method of forming a toner image on an electrostatic latent image formed on a photoreceptor drum of a copying device, there is a method using, for example, a magnetic brush phenomenon.

According to a developing device that utilizes such a magnetic brush phenomenon, for example, toner, which is a non-magnetic material, and Kyrelia, which is a magnetic material, are housed in a casing, stirred by a stirring blade provided in the casing, and further stirred. A developer magnetic brush is formed by magnetic force on the developing roller that is pulled close to the photoreceptor drum by the developer consisting of the toner and carrier, and as a result, the area near the photoreceptor drum and the developing roller is Toner is deposited onto the electrostatic latent image on the photoreceptor drum from the developing roller to form a toner image.

Further, in such a developing device, a toner replenishing section is provided within the developing device, and when the density of the toner contained in the casing becomes low, toner is replenished into the casing from this toner replenishing section. It has become.

The concentration of the toner contained in the casing is detected during copying by, for example, a toner concentration detection sensor that magnetically detects changes in magnetic permeability between the toner, which is a non-magnetic material, and the carrier, which is a magnetic material. ing.

However, since the toner concentration is detected by the above-mentioned toner concentration detection sensor during the copying operation, insufficient agitation occurs due to the stirring blades being stopped just before the start of the copying operation, resulting in insufficient agitation. As a result, the toner concentration detection sensor may determine that the toner concentration has decreased even though it has not decreased, or conversely, it may incorrectly determine that the toner concentration has not decreased even though it has decreased. Sometimes I do.

Furthermore, for example, when a document with a dark image is copied, the density of the toner contained in the casing may drop directly. Since the detection and the copying operation are completed at the same time, when the copying operation is performed afterwards, the toner supply may not be sufficient, and the density of the copied image formed on the recording paper may become very light. .

OBJECTS OF THE INVENTION] The present invention has been made in response to the above-mentioned circumstances, and an object of the present invention is to provide a developing device that can always apply a stable toner of a predetermined density to a photoreceptor.

[Summary of the Invention] In other words, the developing device of the present invention includes a stirring means for stirring a developer, and a toner applying means for applying toner from the developer stirred by the stirring means to an electrostatic latent image on a photoreceptor. a toner concentration detecting means for detecting the concentration of one toner in the developer, and a toner replenishing signal outputting a toner replenishment signal when the toner concentration detected by the toner concentration detecting means decreases to supply the toner from the toner replenishing means to the developer. In a developing device having a small number of toner replenishment control means for replenishing toner, the 1 to 9 degree detection means detects the toner concentration after a predetermined period of time has elapsed since the stirring means started stirring the developer. The apparatus is configured to start detecting the toner density and finish detecting the toner density after a predetermined period of time has elapsed after the toner applying means finishes applying the toner to the electrostatic latent image on the photoreceptor. This makes it possible to always apply toner of a stable predetermined density to the electrostatic latent image on the photoreceptor.

[Embodiments of the Invention] Hereinafter, details of embodiments of the present invention will be described based on the drawings.

FIG. 1 is a longitudinal sectional front view of a developing device according to an embodiment of the present invention.

As shown in the figure, in the developing device of this embodiment, a black toner is transferred to a developing mechanism section A for depositing black toner onto an electrostatic latent image formed on a photoreceptor drum 1. a toner replenishing section B that replenishes toner, and one color other than black, for example, red, on the electrostatic latent image formed on the photoreceptor tram 1.
The main parts thereof include a developing mechanism section C to which toner of yellow, blue, green, etc. is attached, and a toner replenishing section that supplies toner of colors other than black to this developing mechanism section C.

Note that the developing mechanism section C and toner replenishing section corresponding to the developing mechanism section A and toner replenishing section B have almost the same configuration as the developing mechanism section A and toner replenishing section B, and the object of the present invention is to Since they are the same, a redundant explanation will be omitted, and in this embodiment, the developing mechanism section A and the toner replenishing section B will be used for explanation.

First, in the developing mechanism section A, there is a developing roller 2 that applies toner (black) onto the electrostatic latent image formed on the photoreceptor tram 1.
is placed in the casing 3 so as to be close to the photosensitive drum 1 with a predetermined gap therebetween. The developing roller 2 in the casing 3 detects the concentration of toner in the developer by magnetically detecting changes in the magnetic permeability of the developer (toner and rear). (=JG) on the side opposite to the developing device.Furthermore, the developing device is driven by a main motor (not shown) that drives the photosensitive drum 1, etc. provided on the main body side of the copying machine to which this developing device is attached. A stirring blade 5 for stirring the agent is installed between the developing roller 2 and the toner level detection sensor 4 inside the casing 3.

In addition, a leveler 7 that uniformizes the thickness of the developer magnetic brush 6 formed by the magnetic brush phenomenon on the developing roller 2 is placed close to the developing roller 2 with a predetermined gap 6 on the stirring blade 5 side below the developing roller 2. Then take it inside the casing 3 ()
It is being Further, the developer remaining on the developing roller 2 after the toner has adhered to the electrostatic latent image formed on the photoreceptor drum 1 is scraped off by the developing roller 2, and the developer that has been scraped off is removed by the stirring blade 5. The scraper 8, which feeds +fU again, is placed on the side of the stirring blade 5 above the developing roller 2.
It is attached in the casing 3 so that the tip and the tip thereof are in contact with each other.

Further, a magnetic roll 9 is inserted into the developing roller 2.

This magnetic roll 9 has four magnetic pole parts 9a to 9d, of which the magnetic pole parts 9a and 9C are north pole magnetic (the bottom parts 9b and 9d are south poles, and the magnetic pole parts 9a and 9b are The angle is about 9
0°, the angle between the magnetic pole parts 9b and 9c is about 70°, the magnetic pole part 9
The angles between G and 9d are each set to about 80'. Further, the magnetic roll 9 is provided so that its center is located on a straight line 2 drawn approximately at an angle to a horizontal line L1 passing through the center of rotation of the photosensitive drum 1. Moreover, this magnetic roll 9 can rotate at a rotation angle of about 35 degrees, and as a result of this rotational movement, a developer magnetic brush 6 is formed on the surface of the developing roller 2.
are prevented from forming. That is, by not rotating the magnetic roll 9, it is possible to select whether or not toner is to be deposited on the electrostatic latent image formed on the photoreceptor drum 1.

On the other hand, the toner supply section B is connected to the casing 3 of the developing mechanism section A.
The agitating blade 5 is attached above the agitating blade 5 attached to the toner, and toner is supplied onto the agitating blade 5 to the developing mechanism section through a toner replenishing port.

The toner supply section B is provided with a toner hopper 10 for storing toner. A stirring blade 11 for stirring the toner contained in the hopper 10 is attached to the lower right side of the toner hopper 10, and the toner stirring blade 11 has J:
1 to toner replenishing roller 12 for replenishing the agitated 1 to toner onto the stirring blade 5 of the developing mechanism section Δ via the toner replenishing port
is attached to the toner hopper 10 above the toner supply port and close to the toner 1g stirring blade 11.

The detailed structure of the toner replenishing section B will be explained based on the perspective view of the toner replenishing section B shown in FIG.

1 is connected to a toner replenishment roller 12 from one front side of the outer wall of the toner bottle 10.
The feed claw 13 that interlocks and rotates the roller 12 protrudes and d5
A ratchet 14 that is engaged with the feed pawl [3] and rotates in conjunction with the feed pawl [3] is attached to the outer wall of the toner hopper 10, and furthermore, the ratchets 1 to 14 are attached to the outer wall of the toner hopper 10.
- A toner solenoid 5 is attached to the outer wall of the toner hopper 10 above the ratchet 14, and when turned off, the ratchets 1 to 14 advance eastward in the direction of the arrow in the figure via a claw. When a toner replenishment signal, which will be described later, is input to the toner solenoid 15, this 1
~Ner solenoid 15 turns 0N-OFF in response to this signal
By rotating the ratchet 14 and rotating the feed pawl 13 engaged with the ratchet 14, the toner replenishing roller 2 connected to the feed pawl 13 rotates, and the developing mechanism Toner is replenished onto stirring blades 5.

The basic operation of toner replenishment in this embodiment configured as described above will be explained based on FIG. 3.

As shown in the figure, the l.
When the toner level detection sensor 4 detects that the toner concentration of the developer has decreased, this detection signal is sent to the developing device or the copying device to which it is attached, similarly via the input interface 16 provided on the main body side. microcomputer] 7 installed in the computer. The microcomputer 17 to which this detection signal is input calculates the amount of toner to be replenished to the developer, outputs a toner replenishment signal according to the result, and this signal is sent to an output driver on the main body side. 1 to 1 of toner supply section B via 1B.
Installed in Ner Solenoid 10 (Pressed 1 to Ner Solenoid 15)
is input. Then, in the toner solenoid 15, the above-mentioned operation causes the development to occur on the stirring blade 5 of the structure A.
replenish energy.

The basic operation of toner replenishment as described above is carried out, and the detailed operation in this embodiment will be explained based on the flowcharts of FIGS. 4 and 5.

Note that the control operation of the toner replenishment process described below is performed within the interrupt process of a microcomputer provided in the copying apparatus.

First, as shown in FIG. 4, after the main motor is turned on, that is, the copying operation is performed, there is a certain period of time (for example, 5 seconds) until the developer is sufficiently stirred by the stirring blade 5.
It is determined whether a certain period of time has elapsed (step 1), and when a certain period of time has elapsed, it is determined whether there is currently a request for toner capture based on the detection by the toner concentration detection sensor 4 (step 2).

Further, if a certain period of time has not elapsed in step 1, or if there is no toner replenishment request in step 2, the toner solenoid 15 is turned off (step 3).
).

On the other hand, when there is a toner replenishment request in step 2,
After a delay of 0.35 seconds (step 4), it is determined whether the toner solenoid 15 is ON (step 5), and the O
If the answer is N, proceed to step 3. And when the toner solenoid 15 is OFF, the toner solenoid 15 is ON.
1 hener is replenished (step 6).

After that and after step 3, it is determined whether the main motor is rotating (step 7), and if it is rotating, it is fed back to step 2, and if it is not rotating, the operation is ended.

In this way, in step 1, a certain period of time elapses until the developer is sufficiently stirred by the stirring blade 5, and then in step 2, the j opening degree of the toner is detected by the toner level detection sensor 14. Therefore, the toner concentration can be detected only after the temperature thereof has stabilized, thereby making it possible to accurately detect the toner concentration by the toner concentration detection unit 2-4.

Next, the operation after the copying operation in this embodiment is explained based on the flowchart shown in FIG.

When the copying operation is completed (step 8), the following operation is performed for, for example, 15 seconds (
Step 9).

First, the toner vigor sensor 4 determines whether there is a toner replenishment request (step ○), and when a toner replenishment request is received, it is determined whether 15 seconds have elapsed since the end of the copying operation (step 11). ).

Then, when there is no toner replenishment request in step 10 and when 15 seconds have elapsed since the end of the copying operation in step 11, the main motor is stopped (step 12).

Further, when 15 seconds have not elapsed since the end of the copying operation in step 1 and after the main motor has been prevented from stopping in step 12, it is determined whether the function key of the copying apparatus has been pressed (step 13).

If the print key is pressed, the copying operation is started (step 14), and if the print key is not pressed, it is determined whether the main Tanabata switch is turned on (step 15).

When the main motor is ON, it is fed back to step 10, and when the main motor is 0 [F], it is in a standby state.

Even after the copying operation is completed in this way, the temperature of 1-'7 = density is detected by N1-4 for 15 seconds, and if the performance level of 1-'7 has decreased, the toner is detected during this period. Therefore, the copy image formed on the recording paper when the next copying operation is performed after performing the copying operation is the same as the normal 11-button printing. .

[Song Dynasty of the Invention] As explained above, according to the developing device of the present invention, 1 to 1) after a predetermined period of time has elapsed from the start of agitation of the developer by the opening degree detection means or the agitation means. Start detecting the density of :/--, and after a predetermined time has elapsed after the toner applying means finishes applying toner to the electrostatic latent image on the photoreceptor, end detecting the density of toner 1 to With this configuration, it is possible to always apply a stable predetermined density of 1 to thick to the electrostatic latent image on the photoreceptor.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional front view of a developing device according to an embodiment of the present invention, Fig. 2 is a perspective view of a toner replenishing section of this embodiment, and Fig. 3 shows the basic operations of 1 to toner replenishment of this embodiment. The diagrams for explanation, FIG. 4 d3 and FIG. A...Development mechanism section B...Toner supply section 1...Photosensitive drum 2...Development Roller 3...Casing 4...Toner concentration detection sensor 5...
・・・・・・Stirring blade

Claims (1)

[Claims] a stirring means for stirring the developer; a toner applying means for applying toner from the developer stirred by the stirring means to the electrostatic latent image on the photoreceptor; and a toner replenishing means for replenishing the developer with toner; toner concentration detection means for detecting the concentration of toner in the developer; and when the toner concentration detected by the toner concentration detection means decreases, a toner replenishment signal is output, and the toner is replenished from the toner replenishment means to the developer. In the developing device, the toner concentration detection means starts detecting the toner concentration after a predetermined period of time has elapsed since the stirring means started stirring the developer, and A developing device characterized in that it is configured to finish detecting the toner density after a predetermined period of time has elapsed after the toner has been applied to the electrostatic latent image on the photoreceptor by the applying means.