JPH04151178A - Toner supplementing method - Google Patents

Abstract

PURPOSE:To eliminate the breakage of a toner supplementing means and the problem of a defect in development by stopping the toner supplementing means from supplementing toner throughout a period from the detection of a shortage of toner in a developing tank to a toner end display being made. CONSTITUTION:The supply amount of toner can not follow up toner consumption, a sensor output X rises, and this variation is utilized for toner end detection. Then it is indicated that a toner storage part 2 runs short of toner soon, a toner end signal which sets a copy inhibition state is generated, and the toner end display is made. At this time, a toner supplementing roller 1 is stopped from rotating simultaneously with the generation of a toner near-end signal. Namely, the output of a toner concentration sensor S is sent to a central controller(CPU), sampling data X is compared with a reference value (b), and a control signal is outputted to a driver such as a motor driving circuit to control the toner supplementing roller 1 through the motor. Consequently, the breakage of the toner supplementing means and the accompanying problem of a defect in development are eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a toner replenishment method applied to a developing device of an image forming apparatus such as a copying machine, a facsimile machine, and a printer.

(Prior Art) Toner stored in a toner storage section is sent to a developer tank via a toner replenishment means, and the toner is transferred from the developer tank to the development section to perform development. There is a two-component magnetic brush developing device in which a toner end display is made to notify the toner shortage in the toner storage section based on the output of a detection means. In such a developing device, a sensor or the like is used as a detection means to detect the remaining amount of toner, toner density, and image density, and compares it with a standard data value. , the toner end signal is output to indicate the toner end.

(Problem to be Solved by the Invention) By the way, if the remaining amount of toner in the toner storage unit is not directly detected, there will be almost no toner in the toner storage unit even before the toner end signal is output, and therefore the toner storage unit will not have enough toner. The supply means becomes idle. There is no point in operating the toner replenishment means when there is no toner in this way,
This may lead to deterioration of the toner replenishing means such as the toner replenishing roller.

For example, as shown in FIG. 2, toner is sent from a toner container 2 to a developer tank 3 in accordance with the rotation of a toner replenishment roller 1 based on the output of a toner concentration sensor S. It is in contact with a seal 4 made of sponge or the like, and as the toner replenishing roller 1 rotates, frictional movement occurs between the two.

Therefore, in a state where there is almost no toner, the frictional resistance becomes large, and the toner may be softened or the seal 4 may be damaged due to frictional heat. In addition, the softened toner fuses together to form a large lump, and when it adheres to the photoreceptor, which is the developing section, the area around the toner lump during transfer is
This results in poor adhesion between the transfer paper and the photoreceptor, resulting in so-called transfer failure. Further, if the toner is fused within the seal 4 or the seal 4 is damaged, the amount of toner supply changes and the toner tends to clump.

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner replenishment method that can solve problems such as damage to the toner replenishment means and development failures caused by toner clumping. ) In order to achieve the above object, the present invention detects toner shortage in the developer tank by a detection means, and stops toner replenishment operation by the toner replenishment means from the time this detection is made until the toner end display is displayed. It was decided to.

(Function) The toner replenishing means does not operate when there is no toner.

(Example) In FIG. 2 schematically showing the developing device according to the present invention,
The toner replenishing means includes a toner replenishing roller 1 having a V-groove on one side and driven by a motor (not shown), and a seal 4 is in sliding contact with the toner replenishing roller 1. Also, provided within the developer tank 3 are a toner concentration sensor S, a developing roller 5, a paddle roller 6 that supplies toner to the developing roller 5, and the like. The developing roller 5 is disposed close to and facing the photosensitive drum 7, and the toner on the developing roller is transferred to the developing section on the drum to perform development.

The toner concentration of the developer in the developer tank 3 is horizontally compared by a toner concentration sensor S, and based on this detection result, the rotation amount of the toner supply roller is changed to control the toner concentration to a predetermined value. , toner storage section 2
It is now possible to indirectly know if there is a toner shortage in the area.

As shown in Fig. 3, the sensor output changes depending on the toner concentration. For example, when the toner concentration is set at 3 (wt%), the corresponding sensor output A (v)
and B (bit), which is the value obtained by converting this into a digital signal.
is the standard value. Sampling of toner density is performed once for each copy. This sampling data X is compared with a reference value B, and the toner replenishing roller 1 is controlled.

When the toner concentration is low, the number of bits of the reference value B becomes large, and when
) Perform toner replenishment operation. That is, the toner replenishing roller 1 is rotated, the toner adhering to this roller is regulated by the inlet seal 4a, and the toner is scraped off by the outlet seal 4b.
supply to

While there is toner in the toner storage unit 2, according to the reference value B,
Although the toner concentration is controlled, when the toner storage section becomes short of toner, the supply amount cannot follow the toner consumption amount, and the sensor output X increases. This change is used to detect toner end.

For example, if X-B≧10 occurs 10 times in a row, it is determined that the toner is insufficient, and a toner near-end signal indicating that the toner will soon run out in the toner storage unit 2 is generated, and after 100 sheets have been copied.

A toner end signal is generated to notify that the toner is running out and to prohibit copying, and a toner end display is made based on this toner end signal.

Here, at the same time as the toner near-end signal is generated, the rotation of the toner replenishing roller 1 is also stopped.

That is, in FIG. 1, the output of the toner concentration sensor S, which is the detection means, is sent to a central control unit (cpU), and the central control unit performs arithmetic processing such as comparing the sampling data X with the reference value S. A control signal is output to a driver such as a motor drive circuit, and the toner replenishing roller 1 is controlled via the motor.

Note that X-B is the reference for generating the toner near-end signal.
The smaller the value of 10 (≧10), the sooner the toner storage unit 2 runs out of toner and the toner end signal can be generated by detecting the situation. Also, depending on variations in the sensor output, there is a possibility that it may be erroneously detected that the toner end signal is generated when there is still toner in the toner container 2. For this reason, a certain value is required. If we do not take this into consideration, there will be almost no toner in the toner storage unit 2 by the time the sensor output Due to the friction between the supply roller 1 and the seal 4, toner clumps are very likely to occur.

Conventionally, when it is detected that there is no toner in the toner storage section 2, a toner near-end signal is generated to prompt the user to prepare toner, and after a predetermined number of sheets, a toner end signal is generated to prohibit copying. Therefore, the larger the predetermined number of sheets is, the more the above-mentioned problems occur.

In this regard, in this example, after it is detected that there is a shortage of toner in the toner storage section 2, the above-mentioned problem is solved by prohibiting the toner replenishing means from replenishing toner. In addition,
A predetermined number of copies can be made.

According to this example, transfer failure due to stuck toner particles is prevented, deterioration of the toner replenishing means is also prevented, and the service life can be extended.

As the detection means, a toner density sensor may be used as in the above example, or an image density detection means may be used.
The fastest response is to directly detect the toner in the toner storage unit.

(Effects of the Invention) According to the present invention, it is possible to solve problems such as damage to the toner replenishing means and development defects accompanying this.

[Brief explanation of drawings]

FIG. 1 is a control block diagram suitable for carrying out the present invention, FIG. 2 is a diagram illustrating a developing device according to the present invention, and FIG. 3 is a diagram illustrating the relationship between sensor output and toner density. 1... Toner replenishment roller, S... Toner density (etc.
1 person) Ichizora 3 Umikaku “V To↑-Concentration [Ba7]

Claims (1)

[Claims] The toner stored in the toner storage section is sent to a developer tank via a toner replenishing means, the toner is transferred from the developer tank to the development section to perform development, and detection is performed to know if there is a shortage of toner in the toner storage section. In a method for replenishing toner from the toner accommodating section to the developer tank in a two-component magnetic brush developing device, in which a toner end display is performed to notify the shortage of toner in the toner accommodating section based on the output of the means, the detecting section is used. . A toner replenishing method, comprising detecting a shortage of toner in the developer tank, and stopping the toner replenishing operation by the toner replenishing means after this detection.