JPS6034749B2 - Toner remaining amount detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner remaining amount detection device in a developing device of an electronic copying machine.

Generally, in a copying machine that uses one-component non-magnetic toner, the toner is attached to the outer circumferential surface of a developing roller made of conductive rubber, and the toner is frictionally charged to form an electrostatic port on the recording medium. Developing the image.

Therefore, as time passes, the toner is sequentially consumed, and eventually the toner stored in the toner tank runs out and development becomes impossible. When there is a shortage of toner in this way, it is necessary to replenish toner, but since one-component toner does not cause deterioration like two-component developers, it is especially important to check the amount of remaining toner. Toner is replenished after uneven development occurs in the copied image without displaying it. The present invention was made by focusing on the fact that in a developing device using one-component non-magnetic toner, the developing roller is made conductive and a bias potential is applied.The present invention has an extremely simple structure and reliable operation. An object of the present invention is to obtain a toner remaining amount detection device.

The present invention provides a sensing electrode that faces a developing roller having conductivity and to which a bias of a predetermined potential is applied, with a one-component non-magnetic toner interposed therebetween, and the sensing electrode and the developing roller are placed relative to each other. The toner is provided so as to be able to be joined in close proximity to the toner, and a detection section that operates by detecting the toner shortage state is connected to the detection electrode. Therefore, when there is a developable amount of toner, toner with high electrical resistance is present between the developing roller and the detection electrode.
There is no electrical connection between the two, and the toner is completely consumed and development is no longer possible, or just before that, an electrical connection is made between the two and the detection section of the toner shortage display device, toner replenishment device, etc. The device is configured to operate to ensure reliable toner amount detection. A first embodiment of the present invention will be described based on FIGS. 1 and 2.

First, reference numeral 1 denotes a drum-shaped photoreceptor on which a latent image holding layer 2 made of a material such as Se, Zn0, or PVK is formed. A device 5, a supply device 7 for supplying the transfer paper 6, a transfer charger 8, a peeling device including a peeling claw 10 for reliably peeling the transfer paper 6 from the surface of the photoreceptor 1 so as to direct the transfer paper 6 toward the fixing device 9, and a cleaning device 11. Arranged sequentially. The conductive layer 12 provided on the inner peripheral side of the photoreceptor 1 is grounded, and the developing roller 3 of the developing device 5 is made of conductive rubber and is biased with a predetermined voltage by a DC power source 14. There is. Further, the developing device 5 has a downwardly closed hopper 16 that holds the toner 15 above the developing roller 13, and the lower edge of one side of the hopper 16 is made of a triboelectrically charged column made of base resin, polyimide, etc. A frictional charging blade 17 made of a more appropriately selected material is provided. A detection electrode 18 biased downward is provided inside the hopper 16, and an amplifier 19 is interposed in the detection electrode 18 to form a detection section of the toner replenishing device 2.
The river is connected. This detection unit may be a display device using a pilot lamp. Further, the sensing electrode 1
The specific shape of 8 is such that a metal piece that does not sink into the toner 15 is provided parallel to the developing roller 13 in the vertical direction, and the biasing means is provided by the weight of the metal piece or its own splash. This can be done by springs or other springs. In such a configuration, the photoreceptor 1 is charged by the charger 3, bright and dark light depending on the document is applied to the photoreceptor 1 in the exposure section 4, a static latent image is formed on the image holding layer 2, and the developing device 5. That is, the developing roller 3
The toner 15 in the hopper 16 is scraped out by the rotation, and the toner 15 is frictionally charged while forming a toner layer of a constant thickness on the developing roller 13 by the frictional charging blade 17, and brought into close proximity to the photoreceptor 1. At this point, an amount of toner 15 corresponding to the potential of the latent image is supplied onto the photoreceptor 1. At this time, since a predetermined bias potential is applied to the developing roller 13, the toner 15 does not adhere to the background or the like. Next, when the transfer charger 8 applies a corona discharge from the back side of the transfer paper 6 fed from the paper feeder 7, the toner 15 on the photoreceptor 1 is transferred to the surface of the transfer paper 6, and then the peeling claw 10 removes the toner from the photoreceptor. The transfer paper 6 peeled off from the transfer paper 1 is fixed by a fixing device 9. On the other hand, the toner 15 remaining on the photoreceptor 1 is cleaned and removed by the cleaning device 11, thereby completing the cycle.
Copying is performed in this manner, but the toner 15 is sequentially consumed each time a copy is made, until almost no amount of toner 15 remains in the hopper 16.

At this time, the detection electrode 18 comes into contact with the developing roller 13, and a signal is given to the toner replenishing device 20 to supply a predetermined amount of new toner 15 into the hopper 16. That is, when the toner 15 is a one-component nonmagnetic toner, its volume resistivity is 1 to 40 skin or more, and the developing roller 13 is made of silicone rubber or the like whose conductivity is 10-50/skin. When there is toner 15 between the developing roller 13 and the detection electrode 18, the electrical resistance between them is quite high, and when there is a shortage of toner 15, the electrical resistance decreases considerably. Note that when the detection electrode 18 outputs a toner shortage signal, it means that there is almost no toner 15 on the surface of the developing roller 13, so copying is not possible until a sufficient amount of toner 15 is replenished. Set it to .

Next, a second embodiment of the present invention will be explained based on FIG.

The same parts as in the previous embodiment are designated by the same reference numerals, and the description thereof will be omitted. In this embodiment, the hopper 16 is made of an insulating material, and a metal roller 21 serving as a detection electrode is provided at the lower part of the side wall on the opposite side to the side where the frictional charging blade 17 is provided. A toner replenishing device 20 is connected to the roller 21 via an amplifier 19. In such a configuration, as the developing roller 13 rotates, the toner 1
The metal roller 21 rotates with the roller 5 interposed therebetween.

A considerable amount of the toner 15 adhering to the surface of the developing roller 13 is still adhering to the photoreceptor 1 even after the development, and the metal roller 21 is disposed along almost the entire length of the developing roller 13. Therefore, when toner 15 in a developable state exists, a certain thickness of toner 15 exists between developing roller 13 and metal roller 21, and the two are not electrically connected. When the toner 15 is completely consumed and the amount of toner adhering to the surface of the developing roller 13 decreases, the metal roller 21 comes into contact with the developing roller 13 and the toner replenishing device 20 is operated. Further, when there is sufficient toner 15 in the hopper 16, the metal roller 21
The toner 15 rotates under the influence of the turbulent force from the developing roller 13, and the hopper 16 acts as a scraper at the contact portion with the hopper 16, thereby preventing the toner 15 from falling from this portion.

Next, a third embodiment of the present invention will be explained based on FIG.

In this embodiment, the toner 15 is supplied from below the developing roller 13. That is, a toner tank 22 at the upper entrance is provided below the developing roller 3, and within this toner tank 22, a hopper bottom plate 23 made of a metal plate that holds toner 15 is provided as a detection electrode. It is flexible and is constantly urged upward by a spring 24. Further, a frictional charging member 25 is attached to the upper green part of the toner tank 22.
Further, a toner replenishing device 20 is connected to the hopper bottom plate 23 via an amplifier 19. In this configuration, when there is sufficient toner 15 in the toner tank 22, the hopper bottom plate 23 does not come into contact with the developing roller 13, but as the toner 15 is consumed, the hopper bottom 23 rises. Finally, it comes into contact with the developing roller 13 and operates the toner replenishing device 20 in the same manner as in the above case.

The present embodiment has the advantage that the toner 15 can be effectively supplied from below the developing roller 13 while preventing the toner 15 from falling down. Furthermore, a fourth embodiment of the present invention will be described based on FIG. In this embodiment, a metal piece 26 serving as a detection electrode is embedded in the latent image holding layer 2 of the photoreceptor 1 in a state where it is insulated from the conductive layer 12 and whose surface is exposed. Therefore, when the surface toner 15 of the developing roller 13 runs out, electrical connection is established and a toner shortage signal can be obtained. The present invention utilizes the fact that a predetermined bias potential is applied to the developing roller as described above, and provides the developing roller with a removable detection electrode, and detects the remaining amount of toner based on the presence or absence of toner between the two. The structure is extremely simple, and since the detection is based on the presence or absence of toner on the developing roller, it is easy to detect even if the toner is one-component non-magnetic and almost an insulator. This has the effect of ensuring that

[Brief explanation of the drawing]

Fig. 1 is a side view showing a first embodiment of the present invention, Fig. 2 is a longitudinal sectional side view of the main parts thereof, Fig. 3 is a longitudinal sectional side view showing a second embodiment of the invention, Fig. 4 FIG. 5 is a longitudinal side view showing a third embodiment of the present invention, and FIG. 5 is a longitudinal side view showing a fourth embodiment of the present invention. 13...Developing roller, 15...Toner, 1
8...Detection electrode, 20...Toner supply device (detection section), 21...Metal roller (detection electrode), 23...
... Hopper bottom (sensing electrode), 26... Metal piece (sensing electrode). Buzuno map; Zuotsu map

Claims (1)

[Claims] 1. A sensing electrode is provided facing a developing roller having conductivity and to which a bias of a predetermined potential is applied, with a one-component non-magnetic toner interposed therebetween, and the sensing electrode and the developing roller are joined relatively close to each other. A remaining toner amount detecting device, characterized in that the detecting section is connected to the detecting electrode and operates by detecting the toner shortage state.