JPH03251876A - Developing device - Google Patents

Abstract

PURPOSE:To ensure the agitation and supply of a toner and to allow the sure detection of the presence or absence of the toner by rotating and moving a cleaning means with a delay by a prescribed angle in the rotating direction from an agitating member. CONSTITUTION:A cleaner 14 is so fixed to a revolving shaft 7 that its action position comes to the position delayed in the rotating direction of the shaft 7 by the prescribed angle from the agitating action by an agitating rod 8 of the agitating member 6 and a coil spring 9. The cleaner 14 is disposed opposite to a means 13 for detecting the presence or absence of the toner and is rotated by the revolution of the shaft 7 so as to follow up the revolution thereof with the delay by the prescribed angle within a 0 to 90 deg. range from the agitating rod 8 and the spring 9 to clean the member 13. The impairment of the agitating and supplying functions of the agitating member 6 by the cleaner 14 is obviated in this way and the toner is surely agitated and supplied. The presence or absence of the toner is thus surely detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device for an electrophotographic image forming apparatus such as a copying machine, facsimile machine, or printer.

[Prior art]

The storage container includes a developer storage container, a developer stirring member and a piezoelectric developer remaining amount detection means provided in the storage container, and a cleaning means for cleaning a detection surface of the remaining amount detection means. A developing device is known in which a developer supplied from within is carried as a uniform thin layer on a developer carrier, and a latent image on the latent image carrier is developed by the developer carrier.

Conventional developing devices, especially those that perform powder development, are equipped with a developer (toner) presence/absence detection means that detects when the developer runs out or is about to run out. When the means detects that there is no toner, it is generally done so that enough toner remains to print on several dozen sheets. If the remaining amount of toner at the time of toner empty detection is unstable, the number of prints after toner replenishment until toner empty detection is detected will vary, and in the worst case, blurring may occur.

Therefore, as shown in FIG. 4, the stirring rod attached to the rotating shaft 53 of the developer stirring member 52 provided in the developer storage container 51 is divided into a first stirring rod 54a and a second stirring rod 54b. coil spring 55a on each stirring rod.
, 55b, and the first stirring bar 54a and the second stirring bar 5.
4b, and fix a cleaner 57 such as a brush,
This cleaner 57 faces the toner presence/absence detection means 56 fixed to the storage container 51, and as the rotating shaft 53 rotates, the cleaner 57 cleans the toner adhering to the detection means b6, thereby stably supplying toner. However, in the conventional device shown in FIG. 4, which has been attempted, the stirring rod 54 and part of the coil spring of the stirring member 52 are replaced by a cleaner 57 within the range A. Therefore, the agitation function of the agitation member is degraded in the area where the cleaner 57 is provided, and especially when the remaining amount of toner is low, the toner supply function of the agitation member to the supply roller is degraded in the cleaner area, and the amount of toner replenishment is reduced. It will be partially reduced. Therefore, even though toner end has not yet been detected near the time when toner end is detected,
This will cause problems such as partial blurring of the image.

[Problem to be solved by the invention]

An object of the present invention is to solve the above-mentioned conventional problems and provide a developer device that can reliably stir and supply toner and reliably detect the presence or absence of toner.

[Means to solve the problem]

The present invention solves the above problems by cleaning a developer storage container, a developer stirring member and a piezoelectric developer remaining amount detection means provided in the storage container, and a detection surface of the remaining amount detection means. A developer comprising means for carrying a developer supplied from inside the storage container as a uniform thin layer on a developer carrier, and developing a latent image on the latent image carrier with the developer carrier. In the apparatus, the cleaning means is fixed to a rotating shaft of the stirring member, and the cleaning means rotates behind the stirring member by an angle determined in a range of 0@ to 90° in the rotational direction. This problem was solved with a unique developing device.

[Effect]

According to the present invention, a stirring rod and a coil spring are provided on the rotating shaft of the stirring member so as to extend over the entire length thereof,
The cleaner is fixed to the same rotating shaft so that the stirring action position of the stirring rod and coil spring is delayed by a predetermined angle in the rotational direction of the rotating shaft. The cleaner is arranged to face the toner presence/absence detecting means fixed in the storage container of the developing device, and when the rotating shaft rotates, the stirring rod and coil spring are rotated while stirring the entire storage container. After a delay of a predetermined angle within the range of 0 to 90'', the cleaner rotates as if following the movement and cleans the toner presence/absence detection means.Although there is one rotating shaft, the stirring member and cleaner are separately provided. Since the cleaner rotates at predetermined angular intervals, the stirring and supplying ability of the stirring member is not impaired by the cleaner, and the cleaner can sufficiently perform its cleaning function by itself.

〔Example〕

The details of the present invention will be explained based on embodiments shown in the drawings.

In FIGS. 1 and 2, a developer, that is, toner, is supplied by a developing device 2 to a latent image carrier 1, such as a photosensitive drum, on which an electrostatic latent image has been formed, and the toner adheres to the latent image and becomes visible. .

A developing roller 4 that attaches toner to the photosensitive drum is rotatably supported in the container 3 of the developing device 2 . Toner is supplied to the developing roller 4 by a supply roller 5, for example, a conductive urethane sponge roller, and the toner is supplied to the supply roller 5 while being stirred by a stirring member 6.

The stirring member 6 includes a rotating shaft 7 rotatably supported by the container 3;
It includes a stirring rod 8 having a portion extending substantially horizontally in the axial direction of the developing roller 4 fixed to the rotating shaft 7, and a coil spring 9 fitted into the stirring rod 8. This structure is excellent in the function of stirring the toner to even out the toner height and in the ability to supply the toner to the supply roller 5. The toner stirred and supplied by the stirring member 6 is delivered to the supply roller 5.
The toner that is sent to the developing roller 4 and charged by frictional charging is conveyed by the developing roller 4.

The toner layer formed on the surface of the developer roller 4 is formed by a spring 11.
The electrostatic latent image on the photosensitive drum 1 is formed into a thin layer of uniform thickness by the layer thinning blade 10 which is pressed against the developing roller 4, and the electrostatic latent image on the photosensitive drum 1 is visualized.

The storage container 3 includes a toner cartridge 1 for replenishing toner.
2 can be attached, and the toner supplied from the toner cartridge 12 is stirred by the stirring member 6.

A toner presence/absence detection means 13 is fixed to the storage container 3, and as shown in FIG.
3 outputs a constant voltage, and the toner is consumed and level B
As the toner surface descends further down, the sensing means 13 oscillates a signal with the same amplitude and frequency. It is necessary for the detection means 13 to determine the presence or absence of toner in a stable position so that toner can be replenished. Therefore, if the toner adheres to the detection surface 13a of the detection means 13, a malfunction may occur or the detection level of the presence or absence of toner may fluctuate. In order to avoid this fluctuation, a cleaning member (
cleaner) 14 is fixed to the rotating shaft 7. At this time, the cleaner 14 is fixed so as to be located behind the position of the stirring member 6, for example, the stirring rod 8, in the direction of rotation of the rotating shaft 70 by an angle θ shown in FIG.

Since the rotating shaft 7 rotates at a constant speed, the cleaner 14 pushes the detection surface 13b at regular intervals, so even when there is no toner, it is assumed that there is toner while the cleaner passes the detection surface 13b. The output will be the same. Conversely, even when there is toner, the cleaner 13 performs an operation of scraping off the toner immediately after passing the detection surface 13b, so the output is the same as when there is no developer. This time is determined by the shape of the stirring member, the fluidity of the toner, and the rotational speed of the rotating shaft 7.

The toner presence/absence detection means 13 needs to detect the toner in a stable state and in a state in which toner is not stuck to the detection surface 13a. Therefore, it is necessary to detect the detection surface 13a in a stable state after some time has elapsed after either the stirring member 6 or the cleaner 7 has passed. For this purpose, it is necessary to clean the detection surface 13a with the cleaner 14 to ensure that the toner remains in a stable state. Therefore, it is necessary to prevent the stirring member from approaching the detection surface 13a a short time after the cleaner 14 passes the detection surface 13a. In order to enable stable detection in this way, it is preferable that the stirring member 6 passes the detection surface 13a slightly before the cleaner 14, and most preferably the angle θ is between 0 and 90 degrees,
Moreover, the stirring member 6, that is, the stirring rod 8 and the coil spring 9 are located in front of the cleaner 14 in the rotational direction. In this way, the detection by the detection means 13 is stable and reliable, and the stirring and supplying conditions by the stirring member and the cleaning function by the cleaner are satisfied.

〔effect〕

According to the present invention, the working positions of the agitation member and the cleaner are shifted, so that they can perform their functions independently, and can move independently relative to the detection surface of the detection means, and moreover, it is possible to ensure a stable state of the toner. The toner agitation function and the toner supply function are fully exhibited, and the detection means can detect a stable toner surface without toner sticking. Therefore, problems such as insufficient supply such as partial blurring of images and variations in the number of sheets printed until toner empty detection are solved are solved.

According to the present invention, the remaining amount of developer can be detected in a stable state, and the developer can be stably supplied.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the developing device according to the present invention, FIG. 2 is a perspective view with the top open, FIG. 3 is a sectional view showing the relationship between the toner surface and the detection means, and FIG. 4 is a conventional device. FIG. 2 is a diagram corresponding to FIG. 2 of FIG. ■...Latent image carrier 2...Developing roller 6...Stirring member 7...Rotating shaft 8...Stirring bar 9
...Coil spring 10...Thinning blade 13...Detection means 13b...Detection surface Fig. 3 Fig. 4

Claims (1)

[Scope of Claims] A developer storage container, a developer stirring member and a piezoelectric developer remaining amount detection means provided in the storage container, and a cleaning means for cleaning a detection surface of the remaining amount detection means. In a developing device, which carries a developer supplied from the storage container as a uniform thin layer on a developer carrier, and develops a latent image on the latent image carrier with the developer carrier, The cleaning means is fixed to the rotating shaft of the stirring member, and the cleaning means is fixed at an angle of 0° to 0° in the rotational direction with respect to the stirring member.
A developing device characterized in that it rotates backward by an angle determined in a range of 90 degrees.