JPS6313541B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a concentration detection device for a developing device that detects the concentration of developer supplied to the photosensitive surface of a photoconductor.

Generally, in a developing device used in an electronic copying machine, for example, toner, which is a developer stored in a developer storage section, is supplied to the photosensitive surface of a photoreceptor using a magnetic brush. The toner consumed by the continuous supply is sequentially replenished into the developer storage section in the amount consumed by the developer supply member. Then, the mixed toner consisting of the replenished toner and the toner stored in the developer storage section is supplied to the photosensitive surface again in the same manner.

However, since this mixed toner is a mixture of previously stored toner and replenished toner, the toner concentration supplied to the photosensitive surface is constantly changing, which may cause the developing performance of the developing device to be uneven. occurs.

Therefore, developing devices have been developed that are equipped with a density detection device that detects the density of toner supplied to the photosensitive surface and varies the amount of toner replenished to maintain constant development performance. A typical example of the concentration detection device is shown in FIG. That is, this concentration detection device includes a rotary probe a, which is a detector, which is disposed rotatably in contact with the circumferential surface of a magnetic brush d, and a rotary probe a, which is disposed around the probe a facing the circumferential surface of the rotary probe a. The toner on the magnetic brush d attached in the developer storage section c is attached to the circumferential surface of the rotating probe a, and the toner on the rotating probe a is The photocoupler b detects the density as a change in optical reflectance, and based on this detected information, the amount of toner supplied from the developer supply member g is variably controlled by the toner supply roller f.

However, although the toner supplied from the developer supply member g is agitated and mixed with the toner stored in the developer storage section c by the agitator e, it is often not sufficiently agitated, resulting in a high concentration. A problem arises in that the toner portion having a viscosity is supplied to the rotary probe a via the magnetic brush d, and a density different from the actual density is detected, causing a large amount of detection error.

This invention was made in view of the above-mentioned circumstances, and its purpose is to obtain highly accurate developer concentration detection information by constantly supplying developer with a uniform concentration to the detection site. It is an object of the present invention to provide a density detection device for a developing device that can perform the following steps.

An embodiment of the present invention will be described below with reference to FIGS. 2 to 4.
This will be explained with reference to the figures. In the figure, 1 is a main body 1 of the developing device, and this main body 1 is formed to have a width dimension that is approximately the same as the width dimension of a photoreceptor (not shown), and a developer storage section 2 is formed at the bottom. . A mixture of two types of toner, which is a developer, and a carrier, which is a transport medium for the toner, is stored in the developer storage section 2. Further, an opening 3 having a width approximately the same as the width of the photoreceptor is provided on the side of the main body 1, and the peripheral surface faces the opening 3, and a magnet is placed inside the main body 1. A roller 4 is provided. The magnetic roller 4 is rotatably driven by a drive mechanism (not shown). Further, a support cover 5 having an arcuate cross section is attached to the center of the upper wall surface 1a constituting the opening 3, and a metal rotary probe 6 as a detector is mounted inside the support cover 5. Netroller 4
It is rotatably arranged along the coaxial direction.
A photocoupler 7 consisting of a light-emitting element and a light-receiving element, which is a concentration detector, is provided around the rotating probe 6 on the supporting cover 5 so as to face the circumferential surface thereof, and constitutes a concentration detection device 8. ing. Then, the circumferential surface of the rotary probe 6 of the concentration detection device 8 configured as described above is brought into rolling contact with the magnetic brush 9 formed on the circumferential surface of the magnetic roller 4 through the opening of the support cover 5. . Further, a developer supply body 10 is attached to the upper part of the main body 1 and has a width dimension that is approximately the same as that of the main body 1. A supply chamber 10a is formed. Toner, which is a developer for replenishment, is stored in this replenishment chamber 10a. A replenishment port 11 is provided at the bottom of the replenishment chamber 2a by cutting out the upper wall surface 1a of the main body 1 in the width direction, and the replenishment port 11 is made of a porous material such as urethane foam. A toner replenishing roller 12 is provided. Note that the toner supply roller 12 is rotationally driven by a drive mechanism (not shown). In addition, the above-mentioned supply port 11
A strip-shaped blocking plate 13 having a width dimension A serving as a supply restricting member is attached to the center of the supply port, that is, the supply port portion corresponding to the detection portion of the concentration detection device 8.
It covers the outer circumferential surface of the toner replenishment roller 12 corresponding to the detection area, and limits the toner supplied from that area to the detection area via the replenishment port 11 over the A area.

In addition, 14 is a stirrer, and 15 is a scraper.

Next, when the developing device configured as described above is used to supply toner, which is a developer, to a photoreceptor (not shown), the magnetic roller 4 starts rotating as the drive mechanism operates, and the developer storage section 2 A magnetic brush 9 is formed by attracting the carrier, and then toner is successively attracted onto the magnetic brush 9 and applied to a photosensitive surface (not shown). This allows toner to be supplied.

On the other hand, in the developer supply unit 10, the toner supply roller 12 rotates according to the amount of toner consumed by the above-mentioned toner supply, and the high-concentration toner in the supply chamber 10a is sequentially removed from the supply port 11 to the blocking plate 13. The developer storage section 2 is replenished. The replenished toner is then stirred with the developer reservoir 2 by the stirrer 14, and then attracted by the magnetic brush 9 of the magnet roller 4 and reaches a photosensitive surface (not shown). Furthermore, regarding the action of toner supply by the magnetic brush 9, the replenished toner is not directly supplied to the A area of the magnetic brush 9, but is passed from both sides of the A area to the stirrer 14, and then to the magnetic brush 9 and the toner. Toner thoroughly mixed by sliding contact,
In other words, the toner with a uniform density indirectly becomes A.
area and reaches the photosensitive surface. And this A
The uniform toner in the area is attached to the circumferential surface of the rotating probe 6, and the photocoupler 7 detects the density as a change in optical reflectance. Based on this detected information, the toner is supplied from the developer supply member 10. The amount is variably controlled by the toner supply roller 12.

Therefore, toner of a uniform concentration that is sufficiently stirred is always supplied to the detection portion of the rotary probe 6 and the photocoupler 7.

Therefore, highly accurate developer concentration detection information without detection errors can be obtained.

In the above-mentioned embodiment, the supply restricting body was configured with a band-shaped blocking plate to restrict the replenishment of developer to the detection area of the detector and the concentration detector, but the supply restricting body The present invention is not limited to this structure, and any supply restricting body may be used as long as it has a structure that restricts supply to the detection site.

As explained above, according to the present invention, a supply restriction member is provided at the supply port of the developer supply member that replenishes the developer consumed by supplying the developer to the photosensitive surface. Since the supply of developer to the detection area is restricted, developer having a high concentration area is not supplied to the detection area from the developer supply body, and the developer is always sufficiently uniform. A concentrated developer is supplied.

Therefore, highly accurate developer concentration detection information without detection errors can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a conventional concentration detection device, FIG. 2 is a side sectional view showing an embodiment of the present invention, and FIG.
The figure is a perspective view thereof, and FIG. 4 is a schematic perspective view showing the main parts thereof. 2...Developer storage section, 6...Rotating probe (detector), 7...Photocoupler (concentration detector), 1
0... Developer supply body, 11... Supply port (supply port),
13...Break plate (supply restriction body).

Claims (1)

[Claims] 1. The developer stored in the developer storage section is supplied to the photosensitive surface of the photoreceptor, and the developer consumed by this supply is replenished to the developer storage section by the developer supply member, and this mixed development is performed. In a device in which the developer is attached to a detector and the concentration of the developer is detected by a concentration detector, the detector is attached to the supply port portion of the developer supply body corresponding to the detection portion of the detector and the concentration detector. 1. A concentration detection device for a developing device, characterized in that a supply restricting member is provided to restrict replenishment of developer to a portion.