JPS6311635Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a concentration detection device for detecting the concentration of developer in, for example, a copying machine.

For example, density detection devices used in copying machines have conventionally been used in various ways, such as detecting the density of a portion of the photoreceptor that has actually been developed, or detecting changes in impedance due to the passage of developer. The former method has drawbacks such as a time lag between detection and treatment, and the latter method has drawbacks such as errors in the detection level depending on the amount of developer.

The present invention was developed based on the above circumstances, and its purpose is to provide a concentration detection device that can quickly and accurately control concentration and improve concentration detection performance. It's about doing.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a photoreceptor used, for example, in a copying machine, and around this photoreceptor a developing device 2 for developing a latent image formed in advance on the surface of the photoreceptor 1 is provided.

The developing device 2 includes a container 4 that contains the developer a and has an opening 3 on the side facing the photoreceptor 1, and a container 4 that stores the developer a based on the output of a concentration detecting device 5, which will be described later. Replenishment device 6
Then, in order to supply the developer a in the container 4 to the surface of the photoreceptor 1 through the opening 3, the developer a is transferred to the surface of the photoreceptor 1 while being magnetically attracted to the circumferential surface in a brush-like manner. A magnet roller 7 as a developer transport roller for sliding, and this magnet roller 7
and a concentration detection device 5 for detecting the concentration of the developer a transported by the developer.

The concentration detecting device 5 is the magnetic roller 7.
A detection probe 8 in the form of a roller, for example, which adheres to the peripheral surface of the developer a to be transferred, a detector 9 which detects the concentration of the developer a adhered to the probe 8, and houses the detection probe 8. Storage part 1
0. The detection probe 8 partially connects the peripheral wall of the container 4 to the container 4.
It protrudes into the container 4 through an opening 13 formed in the upper plate 12 and is attached to the magnet roller 7 so that it is not supplied to the surface of the photoreceptor 1 and is removed from the container 4.
It is provided in contact with the developer a that is returned to the inside, and rotates in the opposite direction to the magnet roller 7, that is, the circumferential surface moves in the same direction as the circumferential surface of the magnet roller 7, and the circumferential speed is as high as the above. The circumferential speed of the magnet roller 7 is set to below. The detector 9 has a light emitter 14 that illuminates the circumferential surface of the detection probe 8 and a photoreceptor 15 that receives reflected light from the circumferential surface of the detection probe 8, which are attached to the cover, and the detection output The replenishment amount of the developer a by the replenishing device 6 is controlled based on the comparison result between the value and the reference set value, and the density of the developer a is controlled. The cover 11 is attached to the upper part of the container 4 and surrounds the outer part of the container 4 of the detection probe 8 with a predetermined gap, so that the housing part 10 is connected to the inside of the container 4 through the opening 3. It's communicating. The housing portion 10 has shield materials 16, 16 at the opening edge. That is, the base ends of the shield materials 16, 16 are held between the upper plate 12 of the container 4 and the cover 11, and the tips are close to the detection probe 8, and are suspended as the detection probe 8 rotates. The developer a is prevented from being drawn into the storage section 10.

According to the above configuration, since the developer concentration in the container 4 of the developing device 2 is directly detected, there may be a time lag between detection and treatment as in the conventional case, and the amount of developer a. Therefore, there is no error in the detection level, and concentration control can be performed quickly and accurately.

Further, since the circumferential speed of the detection probe 8 is set to be lower than the circumferential speed of the magnet roller 7, the concentration detection performance can be improved. That is, as shown in an experimental example in FIG.
A cleaning effect acts on the surface of the detection probe 8, and even if the developer a comes into contact with the surface of the detection probe 8, the amount of the developer a attached becomes extremely small, so that the detection performance becomes unstable and significantly deteriorates. On the other hand, when the circumferential speed of the detection probe 8 is lower than the circumferential speed of the magnet roller 7, there is no cleaning effect and density detection can be performed satisfactorily.

Further, since shielding materials 16, 16 are provided at the opening edge of the housing part 10 of the cover 11 to prevent the floating developer a from being drawn into the housing part 10 as the detection probe 8 rotates, the light emitting body 14 and the light receiving part body 1
Sensitivity is not impaired due to floating developer a adhering to 5, and proper density control can be maintained for a long period of time.

In addition, in the above embodiment, the accommodating portion 1 of the cover 11
Shielding materials 16, 16 are provided at the opening edges of 0 to prevent the floating developer a from being drawn into the storage portion 10 as the detection probe 8 rotates. As shown in FIG. 3, the cover 11 has a discharge port for discharging the floating developer a drawn into the storage portion 10 as the detection probe 8 is transferred to the outside before the floating developer a reaches the detector 9. Even if 17 is provided, the same effect as in the above embodiment can be obtained.

As explained above, according to the present invention, a detection probe that attaches and transfers the developer transferred by the developer transfer roller, and a detector that detects the concentration of the developer attached to the detection probe are provided. Because of this, there is no time lag between detection and treatment, and there is no error in the detection level due to the amount of developer, and density control can be performed quickly. Moreover, since the circumferential speed of the detection probe is set to be lower than the circumferential speed of the developer transfer roller, an appropriate amount of the developer transferred by the developer transfer roller can be attached to the detection probe.
This provides excellent effects such as improved concentration detection performance.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional front view showing one embodiment of the present invention;
Fig. 2 is a diagram showing the relationship between the ratio of the peripheral speed of the detection probe to the peripheral speed of the magnet roller in the embodiment and the output of the detection device, and Fig. 3 is a vertical cross-sectional side view showing another embodiment. a... developer, 7... developer transport roller (magnet roller), 8... detection probe, 9... detector, 10... container, 11... cover, 16...
…Shielding material, 17…exhaust port.

Claims (1)

[Claims for Utility Model Registration] (1) A roller-shaped detection probe that is provided opposite to a developer transfer roller and that adheres to and transfers the developer that is transferred by the developer transfer roller; The sensor includes a detector that detects the concentration of the adhered developer, and a cover that has a housing section that accommodates the detection probe, and the detection probe rotates in the opposite direction to the developer transfer roller and adjusts its circumferential speed to the above-described speed. A concentration detection device characterized in that the peripheral speed of a developer transport roller is set to a value lower than that of a developer transfer roller. (2) A request for registration of a utility model characterized in that the accommodation section of the cover has a shielding material on the edge of the opening to prevent floating developer from being drawn into the accommodation section as the detection probe is transferred. The concentration detection device according to item 1. (3) The cover is characterized in that it has a discharge port for discharging floating developer drawn into the storage section as the detection probe is transferred to the outside before the floating developer reaches the detector. A concentration detection device according to claim 1 of the utility model registration claim.