JPH0324573A - Powder level detecting device for powder storage chamber - Google Patents

Abstract

PURPOSE:To reduce the size and cost of the device by switching a voltage to be applied to a vibration surface between a measurement voltage for obtaining presence/absence information on powder and a voltage for giving the vibration surface an amplitude. CONSTITUTION:The voltage applied to the vibration surface 10 is switched between the measurement voltage for obtaining the presence/absence information on the powder 9 and the caking preventive voltage for giving a larger amplitude than the measurement voltage under the condition where the powder 9 contacts the vibration surface 10. For example, a voltage of 10V with which the vibration surface vibrates definitely even when buried in toner completely and a voltage of 5V with which the vibration has a large difference in amplitude or frequency according to whether the vibration surface is in the toner or exposed are applied repeatedly to a toner sensor 10. Consequently, detection is made accurate and the device is reduced in size and cost.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is used to determine whether or not a toner hopper for replenishing toner to a developing device such as a dry copying machine has enough toner. Regarding powder level detection equipment,
In particular, powder storage chambers that use powder detection means to output information on the presence or absence of powder because the vibration changes when the powder comes into contact with a vibrating surface that vibrates when a voltage is applied are used to detect the powder level. This invention relates to a powder level detection device.

[Conventional technology]

When the above-mentioned powder level detection device is used in the toner replenishment hopper to the developing device, the detection device detects that the toner has exceeded a predetermined level even though the toner is stuck to the vibrating surface and there is no more toner in the hopper. It may give false information that there is. Therefore, in order to solve this problem, conventional detection devices move in contact with or close to the vibrating surface, as known from Japanese Utility Model Application No. 56-167362 and Japanese Patent Publication No. 64-5708. A method has been adopted in which a reciprocating member such as a wiper is used to prevent toner from sticking to the vibrating surface, or another vibrating member is used to hit the vibrating surface to prevent toner from sticking. This method not only requires reciprocating members, vibrating members, and their driving means, making the detection device large and expensive, but also has the problem that the vibrating surface is easily damaged by friction and impact caused by external forces. is newly created.

[Problem to be solved by the invention]

The present invention was made in order to solve the above-mentioned problems, and prevents powder from sticking without applying friction or shock due to external force to the vibrating surface, and thus enables accurate determination of the presence or absence of powder. The purpose of the present invention is to provide a powder level detection device for a powder storage chamber that provides information and does not cause wear and tear on a vibrating surface and does not increase the size or cost of the device.

[Means to solve the problem]

The present invention provides powder detecting means for detecting the level of powder, which outputs information on the presence or absence of powder when the powder comes into contact with a vibrating surface to which a voltage is applied and the vibration changes. In the powder level detection device in the storage chamber, the applied voltage is a measurement voltage for obtaining information on the presence or absence of powder, and a measurement voltage for preventing powder from adhering to the vibrating surface. A powder level detection device for a powder storage chamber is characterized in that the powder level detection device for a powder storage chamber is configured to switch to a sticking prevention voltage that gives a larger amplitude than the measurement voltage under conditions where the measurement voltage is higher than the measurement voltage.

[Effect]

That is, in the powder level detection device of the present invention, the applied voltage that causes the vibrating surface to vibrate is changed from the measurement voltage at which the vibration changes greatly depending on the change in the contact state of the powder to the vibrating surface to the voltage that causes the powder to come in contact with the vibrating surface. Since the powder is prevented from sticking to the vibrating surface by switching to an anti-sticking voltage that produces vibrations with a larger amplitude than the measurement voltage under the conditions of There is no need for a reciprocating member or a vibrating member, so there is no need to give false information that there is powder even though it is gone, the device can be made smaller and cheaper, and there is less wear and tear on the vibrating surface. .

〔Example〕

The present invention will be explained below using illustrated examples.

Fig. 1 is a schematic diagram showing the structure of an example in which the detection device of the present invention is used in a toner supply hopper to a developing device of a copying machine, Fig. 2 is a toner sensor circuit diagram, and Fig. 3 shows the voltage applied to the detection device by the control device. 5 is a voltage switching time chart.

In FIG. 1, ■ is an image form or object that rotates in the direction of the arrow and an electrostatic image is formed on the surface by an electrostatic image forming means (not shown), and 2 rotates in the direction of the arrow and is an internal magnet body. The developer from the mixture of magnetic carrier and toner is adhered to the surface of 'C by the magnetic force of 3 from the developer reservoir 4 and transported, and the developer whose layer thickness is regulated by the layer thickness regulating blade 5 during transport. This is a developer transporting body that transports the developer until it is developed and separated by a layer and returns it to the developer reservoir 4, and the electrostatic image of the image form or body 1 is developed into a toner image with the developer layer transported by the developer transporting member 2. In some cases,
A control device applies a bias voltage to the developer transport body 2 using a bias power source. 7 is a stirring means for uniformly stirring and mixing the developer in the developer reservoir 4 and triboelectrically charging the toner; 8 is a toner supply roller for replenishing the toner in the toner hopper 9 to the developer reservoir 4; IO is shown in detail in FIG. This is a powder detection means, that is, a toner sensor, and the toner sensor 10
is installed on the side wall of the toner hopper 9 with its vibrating surface facing inside.

In this example, when the main switch of the copying machine is turned on as shown in FIG. A voltage such as IOV, which clearly oscillates, is applied for a period of time that is short enough to prevent the toner from sticking to the vibrating surface, such as 100 cycles, and then the toner sensor l is
Apply a voltage such as 5V, which causes a large difference in the amplitude or frequency of vibration between when the vibrating surface is buried in toner and when it is exposed from the toner, to O within a range that does not cause toner to stick to the vibrating surface. The voltage is applied for a suitably long period of time, for example, 30 minutes, and then the voltage is applied to the toner sensor IO in such a manner that the above steps are repeated. Then, the control device determines when the toner in the toner hopper 9 has decreased below the installation position of the toner sensor 10 based on the output of the toner sensor 10 while applying the measurement voltage of 5V to the toner sensor 10, and displays the presence or absence of toner. Displays that the toner is running out.

〔Effect of the invention〕

The powder level detection device of the present invention switches the voltage for vibrating the vibrating surface of the powder presence/absence detecting means to the measurement voltage and the sticking prevention voltage, so that the powder level can be leveled without causing the powder to stick to the vibrating surface. Since the detection is carried out, the detection is not only accurate and the device can be constructed compactly and inexpensively, but also has the effect of being excellent in durability. Note that the powder level detection device of the present invention is applicable not only to the toner storage chamber of the developing device, but also to the toner storage chamber of the developing device.
It can also be applied to other powder storage chambers.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the structure of an example in which the detection device of the present invention is used in a toner supply hopper to a developing device of a copying machine, Fig. 2 is a toner sensor circuit diagram, and Fig. 3 shows the voltage applied to the detection device by the control device. It is a voltage switching time chart. l... Image shape or body 3... Magnet body 5... Layer thickness regulating blade 6... Scraping blade 8... Toner supply roller lO... Toner sensor

Claims (2)

[Claims] (1) Powder storage using a powder detection means for detecting the powder level, which outputs information on the presence or absence of powder when the powder comes into contact with a vibrating surface that vibrates when a voltage is applied, and the vibration changes. In a powder level detection device in a chamber, the applied voltage is used as a measurement voltage to obtain information on the presence or absence of powder, and a measurement voltage to prevent powder from adhering to the vibrating surface when the powder is in contact with the vibrating surface. 1. A powder level detection device for a powder storage chamber, characterized in that the powder level detection device for a powder storage chamber is configured to switch to a sticking prevention voltage that gives a larger amplitude than the measurement voltage under certain conditions. (2) Powder in a powder storage chamber according to claim 1, wherein the powder is toner used in a dry copying machine or the like, and the powder storage chamber is a toner hopper that stores toner to be supplied to a developing device. Level detection device.