JPH04186268A - Developing device - Google Patents

Abstract

PURPOSE:To obtain a good image without low density and lack of the image through preventing clogging of toner during supply of the toner by starting a drive of a carrying means in a carrying portion before the supply of the toner from a supplying vessel. CONSTITUTION:Signal T becomes ON in the case where toner exists more than the preset amount in a developer vessel, and OFF in the case where less than the preset amount. When the signal T is OFF for DELTAT1 sec, an electromagnetic clutch becomes ON, and further after additional time of (DELTAt1-DELTAT1) sec, the toner begins to be supplied. Next, if the signal T is ON continuously for DELTAt2 sec, the supply of the toner is stopped, and at the same time, the electromagnetic clutch becomes OFF, and all operations concerning the supply of the toner are finished. In this case, DELTAt1>DELTAT1 is a necessary condition for performing the above-mentioned operations. If the supply of the toner from a hopper begins according to this setting condition, the toner always does not exist at the outlet port of the hopper.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is utilized in the field of image forming technology such as electrophotographic copying machines and information recording devices, and is particularly applicable to latent images formed on electrostatic latent image carriers. The present invention relates to a developing device for converting an image into a visible image using a developer.

[Prior Art] Recently, as the need for color copying has increased, the number of inexpensive and compact monochrome copying machines has been increasing.

In such a copying machine, since a plurality of developing devices are provided in a limited space around the electrostatic latent image carrier, each developing device is miniaturized and its developer storage capacity is also small. turn into. Therefore, a developer supply container (hereinafter referred to as a hopper) is often provided separately. In this case, whether it is ideal to supply the developer from the hopper to the developing device uniformly over the entire axial direction of the developer carrier, or because there is not enough space above the developing device, it is difficult to It extends in the axial direction beyond the length of the electrostatic latent image carrier, and a hopper is provided in the extended portion, and developer is supplied from the hopper to the developing device.

FIG. 3 is a schematic diagram showing an example of the conventional device described above. In FIG. 3, the one-component magnetic toner that is the developer is
From the hopper (not shown), which is a replenishment container, provided at the upper end of the toner transport device i12, which is the transport section at the front end in the figure, the developer container (hereinafter referred to as
The toner is supplied to the toner conveying device 12 in response to a signal from a toner amount detecting element, which is a developer detecting means, attached to the end surface of the toner (simply referred to as a container). At the same time, in response to this signal, the electromagnetic clutch gear (not shown) is turned 0N-O.
The screw 12A, which is a conveying means, is engaged with the gear that rotates the stirring member 13 in the direction of arrow C.
When the screw 12B rotates in the direction indicated by the arrow, the supplied toner is transported from the front side to the back side in the figure, and when it is returned from the back side to the front side in the figure by the rotation of the screw 12B in the direction indicated by the arrow. The developer gradually overcomes the developer amount regulating member 12c of the device 12 and falls almost uniformly in the longitudinal direction of the container into the interior of the container where the stirring member 13 is present. A plurality of elliptical plates or stirring members 13 are provided diagonally across the shaft in the axial direction, and have a circular shape when viewed from the axial direction. Further, at this time, the developer amount regulating member 12G has a shape that is tapered or lowered uniformly from the back side to the front side. Further, the fallen toner is supplied to the developing sleeve 30 while being leveled by the rotation of the stirring member 13 in the direction of arrow C.
The developing screen 30 is conveyed by rotation in the direction of arrow B, coated in a thin layer by the developer layer regulating plate 31, and further conveyed to the developing section which is the closest part to the photosensitive drum 1, and is subjected to a predetermined developing method. Developed.

FIG. 4 is an enlarged schematic diagram of the electromagnetic clutch gear portion explained in FIG. 3. In FIG. 4, Gl is the developing sleeve 3
0 drive gear, G4 the stirring member drive gear, G5 the electromagnetic clutch gear, G6 and 67 the screw drive gear. When the electromagnetic clutch 40 is OFF, the spring 41 causes the gear G5 to shift to the gear G4. Gear G6 does not mesh with G6 and does not rotate, but when electromagnetic clutch 40 is ON, gear G
5 is gear G4. Engages with G6, screws 12B, 1
2A starts rotating and transports the toner.

[Problems to be Solved by the Invention] However, when the above-mentioned conventional example uses a developing device to achieve image development durability, there is a problem that the image density becomes low or image defects occur due to insufficient toner supply. There was a point.

After investigating these phenomena, it was found that the cause was that the toner that was supposed to be supplied from the hopper was clogged at the hopper outlet and was not being supplied.

In other words, electromagnetic clutch gear G5 or gear G4. If it doesn't mesh properly when it meshes with the G6, the rotation of the screw will be delayed or the rotation of the screw in the hover will be delayed, so the toner supplied from the hopper will get clogged at the outlet for a moment, and even if the screw starts to rotate, it will still be toner. I realized that this was due to the phenomenon of not falling.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide a developing device that does not cause toner clogging at the hopper outlet and can form good images without low image density or image defects due to insufficient toner supply.

[Means for Solving the Problems] According to the present invention, the above objects include: a developer container that accommodates a developer; a developer carrier rotatable at the opening of the developer container; a stirring means rotatably disposed in a developer container at the rear of the body;
Communication between the developer supply means and a conveyance section whose internal spaces are in communication with each other, and through which the developer supplied from the developer supply means is conveyed by the conveyance means in the longitudinal direction of the developer carrier, and the conveyance section. a developer amount regulating member disposed in the communication opening along the longitudinal direction so as to regulate the amount of developer supplied from the opening to the stirring means side; and a developer amount regulating member disposed in the communication opening section so as to replenish the developer to the conveying section. a developer detection means for detecting the amount of developer in the developer container, and a means for driving a conveying means when the amount of developer becomes less than a predetermined amount according to the developer detection means; and control means configured to start the transfer from the replenishment container after starting the replenishment container.

[Operation] According to the present invention, when the developer detection means detects that the amount of developer is less than a predetermined amount, the conveyance means of the conveyance section is driven, and then conveyance from the supply container is started. Therefore, the developer transported from the replenishment container moves smoothly, and toner clogging does not occur near the outlet of the replenishment container.

[Example] A first example and a second example of the present invention will be described based on the accompanying drawings. Note that descriptions of parts common to the conventional devices shown in FIGS. 3 and 4 will be omitted.

First Embodiment First, a first embodiment of the present invention will be described based on FIG.

FIG. 1 is a timing chart for explaining the first embodiment of the present invention, in which signals from a toner amount detection element serving as a developer detection means, rotation of a screw in a hoverer serving as a replenishment container, and ON/OFF of an electromagnetic clutch are shown. It shows the timing.

In FIG. 1, the T signal is a signal from the toner amount detection element, which indicates that the amount of toner exceeds the set value in the developer container (hereinafter referred to as
It turns ON when the amount is in the container (simply referred to as a container), and turns OFF when the amount is below the set value. The operation when using the timing chart in FIG. 1 will be explained below.

Figure 3: When I tested the image output using a basket developing device, the ■ signal started to turn ON and OFF repeatedly.
If it lasts even longer, it will always become F. Is it a T signal or 61?
In the case of leaf F for 5 seconds continuously, first the electromagnetic clutch turns ON, screws 12A and B start rotating, and the (Δt1-
ΔT+) The screw in the hopper (not shown) begins to rotate and toner begins to be supplied to the bottle opener.

When the toner supply starts, the T signal repeats ON-OFF again, and as the toner continues to be supplied, it becomes always ON. If the T signal is ON continuously for 2 seconds, the screw inside the hopper stops rotating and the supply of toner is stopped.
At the same time, the electromagnetic clutch turns OFF, and screw 12A
, B stop, and all operations related to toner supply are completed.

Also at this time, Δ1. >ΔT1 is a necessary condition for performing the above operation, and in this embodiment, the following settings were made.

Δt = 0.6 (sec), Δt 2 = 0.
3 (see) T I = 0.3 (sec) Under these setting conditions, we conducted an image development test using the basket type developing device shown in Figure 3. When toner replenishment from the hopper was started, the exit of the hopper Since all parts are constantly running out of toner, there is no toner clogging when replenishing the toner, which was the case in the past, and even after image reproduction durability, good images are produced without poor image density or image defects. I was able to continue gaining.

<Second Embodiment> Next, a second embodiment of the present invention will be described using FIG. 2. Note that the same reference numerals are given to the same parts as in the first embodiment, and the explanation thereof will be omitted.

In Figure 2, after the screw in the hopper stops rotating and toner supply is stopped, the electromagnetic clutch or leaf F is activated. In other words, if the T signal is ON for 2 seconds Δt continuously during toner replenishment, the screw in the hopper will first stop, stop toner supply, and then (ΔT2 - Δt
2) When the bottle is opened, the electromagnetic clutch is turned OFF, the rotation of the conveying screws 12A and 12B is stopped, and all operations related to toner supply are completed. At this time, Δ1. ＞In addition to ΔT1, ΔT
2>Δt2 is a necessary condition, and in this embodiment, the following settings were made.

Δt = 0.4 (sec), Δt 2 = 0.
3 (sec) ΔT, = 0-3 (sec), ΔT
2 = 0.6 (sec) In this way, the screw of the conveying device is already rotating before toner is replenished from the hopper, and even after the replenishment is stopped, the screw continues to rotate for a while, so that the hopper is constantly Since a toner-free state can be created at the outlet of the toner, it is more effective in eliminating toner clogging.

Furthermore, the screw of the conveyance device is constantly rotating while the sleeve is rotating, that is, the gear G5 in FIG. 4 is always rotating as the gear G4. Even when engaged with G5, the effects of the present invention could be similarly exhibited.

Moreover, all the embodiments carried out above can be carried out by using -1 screw instead of using two screws in the conveying device as shown in FIG. in this case,
Toner is replenished from the front side, transported to the back side, and then falls into the container, and all the toner that did not fall from the bank falls from the back end into the container. However, the effects of the present invention have been fully demonstrated.

[Effects of the Invention] As described above, according to the present invention, the driving of the conveying means of the conveying section is started before toner is supplied from the replenishment container, and preferably, before the toner is supplied from the replenishment container. By continuing to rotate for a while after stopping, it is possible to eliminate toner clogging during replenishment and provide a good image without image density being low or image chipping.

[Brief explanation of the drawing]

FIG. 1 is a timing chart of the first embodiment of the present invention, FIG. 2 is a timing chart of the second embodiment of the present invention, and FIG.
The figure is a sectional view showing the schematic configuration of a conventional device, and FIG.
2 is an enlarged schematic diagram of a gear portion of the device; FIG.

Claims (3)

[Claims] (1) A developer container that accommodates developer, a developer carrier that is rotatable at the opening of the developer container, and a developer container that is rotatably disposed in the developer container behind the developer carrier. an agitation unit, a developer supplying unit, and a conveying unit whose internal spaces are in communication with each other, and which causes a conveying unit to convey the developer supplied from the developer supplying unit in the longitudinal direction of the developer carrier; A developer amount regulating member disposed in the communication opening along the longitudinal direction so as to regulate the amount of developer supplied from the communication opening of the conveyance section to the agitating means side, and a developer amount regulating member disposed in the communication opening along the longitudinal direction, In a developing device equipped with a replenishment container for replenishing developer, a developer detection means detects the amount of developer in the developer container, and when the developer detection means detects that the amount of developer falls below a predetermined amount, A developing device comprising: a control means configured to start transporting from the replenishment container after starting driving of the transporting means. (2) The developing device according to claim (1), wherein the conveyance means is constantly rotating while the developer carrier is rotating. (3) The control means is set to stop transporting the developer from the supply container when the developer detecting means detects that the amount of developer is more than a predetermined amount, and to stop the transporting means after a predetermined period of time. The developing device according to claim (1).