JPH0264673A - Toner exhaustion detecting device - Google Patents

Abstract

PURPOSE:To obtain an inexpensive toner exhaustion detecting device excellent in operability and reliability by rotating two fillers of different flexibilities together with an agitator and detecting the condition of remaining toner from the flexure amount of the fillers. CONSTITUTION:At least two fillers 10 and 22 with different flexibilities are placed on toner agitating mechanisms 7 to 9 so that the fillers can rotate with the agitator 9. If a large amount of toner remains, the two fillers flex because of resistance, and the difference in the flexure amount between them becomes greater, whereas if a small amount of toner remains, the fillers hardly flex because of less resistance and the flexure amount becomes smaller. As a result, the condition of remaining toner, that is, toner exhaustion, can be detected. Thus, the inexpensive toner exhaustion detecting device excellent in reliability and operability can be obtained.

Description

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

[Conventional technology]

Conventionally, residual toner detection devices have been used to detect the amount of toner remaining in the toner container in such a developing unit.
For example, as seen in Japanese Utility Model Application Publication No. 63-19863, a pressure-sensitive sensor is provided on a stirring rod that is supported by a toner container and rotates to sweep the inside of the toner container, or as shown in Japanese Utility Model Application Publication No. 63-19864. As shown in , there is a stirring rod having a slit in the middle, with a light-emitting element at one end of the slit and a light-receiving element that receives the light at the other end.

[Problem to be solved by the invention]

However, since the former uses a pressure-sensitive sensor, the cost of parts is high, and since the signal is extracted from the pressure-sensitive sensor to the outside by a contact method, there are problems in that operability and reliability deteriorate.

On the other hand, in the latter case, since a light-emitting element and a light-receiving element are provided on the stirring rod, not only does the cost of the parts become high, but also there are problems in that reliability is poor due to changes in detection sensitivity due to contamination.

The present invention has been made in view of the above points, and an object of the present invention is to provide a low-cost toner end detection device that has low component costs and excellent operability and reliability.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a toner agitation mechanism installed in a toner container with at least two fillers having different flexibility so as to rotate together with an agitator, and the amount of deflection of each filler is The present invention provides a toner end detection device including a remaining toner state detection means for detecting the remaining toner state by detecting the difference between the toner state and the remaining toner state.

Furthermore, in the toner end detection device described above, a magnetic piece is provided at the tip of each filler, and the remaining toner state detecting means detects the position of the magnetic piece of each filler using a Hall element.

[For production]

In the toner end detection device according to the present invention configured as described above, at least two fillers of different flexibility provided in a 1-toner agitation mechanism installed in a toner container so as to rotate together with an agitator detect residual toner. When there is a large amount of toner remaining, the resistance causes the toner to bend and the difference in the amount of deflection becomes large; when the amount of remaining toner is low, the resistance is low, so there is less deflection, and the difference in the amount of deflection is also small. In other words, toner end can be detected.

If a magnetic piece is provided at the tip of each filler and the remaining toner state detecting means detects the position of the magnetic piece using a Hall element, toner end can be easily detected.

〔Example〕

Embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a perspective view showing a main part of a developing unit equipped with a toner end detection device in an electronic copying machine according to the present invention, and FIG. 2 is a side view thereof.

In FIGS. 1 and 2, a photoconductor (OPC) drum 3
A developing roller 4. Supply roller 5. A blade assembly 6 and an agitator assembly 7 are each provided rotatably in the direction of the arrow.

The agitator assembly 7 is formed by fixing one side of a plate-shaped agitator 9 in which a plurality of holes 9a for toner escape are formed at predetermined intervals to an agitator shaft 8, and includes two fillers 10 and 11 having different flexibility. Opening hole 9a of agitator 9
It is mounted at a position corresponding to the agitator 9 so as to rotate together with the agitator 9.

A magnetic piece 12.13 is attached to the tip of each of the feelers 10.11.

On the other hand, on the outside of the lower case 2b, a detection board 17 for detecting a magnetic field is disposed close to the outer surface thereof, and has a pair of Hall elements 15, 18 provided at a predetermined interval.

18 is a cable for outputting the detected signal.

In this embodiment, the right half of the developing unit 1 is a toner supply section which is a toner container section, and the left half is a toner thin layer section.

In the toner supply section, the toner container portion of the lower case 2b is formed in a semi-cylindrical shape, and the toner 14 is contained inside the toner container portion.
An agitator assembly 7 serving as a toner stirring mechanism rotates an agitator 9 clockwise around an agitator shaft 8 to agitate the toner 14 and supply it to the replenishment roller 5 .

When this agitator assembly 7 rotates, 2
The fillers 10 and 11 of the book also rotate at the same time, and the toner 14
When there is a large amount of flexure, the feeler 11 with greater flexibility will be largely bent due to the physical resistance, and the filler 10 with less flexibility will not be deflected much.

Therefore, when there is a large amount of toner 14, the distance between the magnetic pieces 12 and 13 becomes large.

When the remaining amount of toner 14 is small, the resistance is small, so neither filler bends much. Therefore, magnetic piece 1
The interval between 2 and 13 also becomes smaller.

Furthermore, as can be seen from Figures 1 and 2, the filler io
, it have appropriate positional deviations in both the radial direction and the thrust direction with respect to the agitator shaft 8, and have a layout that does not interfere with each other.

The detection board 17 is attached to the main body of the laser printer (not shown) and is completely separated from the developing unit 1.

The Hall element 1 provided on this detection substrate 17
5 and 16 are sensitive to the strength of the magnetic field, and output their detection signals via a cable 18 to a comparator of a toner end detection circuit, which will be described later.

FIG. 3 shows an example of a toner end detection circuit.

This toner end detection circuit includes the aforementioned Hall element 15.
．． 18, comparators 20 and 21, and a NAND circuit 22, and outputs a negative logic toner end signal TEND to a CPU of a control section (not shown).

When the amount of toner 14 in the developing unit 1 is large, the distance between the magnetic pieces 12 and 13 increases as described above.
Since the Hall elements 15 and 16 are never turned on at the same time and the NAND condition of the NAND circuit 22 is not satisfied, the toner end signal TEND is always high.

When the remaining amount of toner 14 becomes low, two fillers 10
．． 11, the deflection is reduced, and the magnetic material piece 12.1
3 becomes close to the distance between Hall elements 15.1E3, Hall elements 15.16 turn on at the same time, and the outputs of comparators 20 and 21 both become high, causing the NAND circuit 22 When the condition is met, the output is
That is, the toner end signal TEND=L (low) is output.

Actually, since the toner end signal TEND is not a status signal, time management is performed by a CPU or the like of a control section (not shown).

That is, when the toner end signal TEND does not become "low j" within the time required for at least the less flexible (rigid) filler 10 to rotate once, it is determined that toner is present.

Note that the toner 14 in this embodiment is preferably made of a non-magnetic material.

As described above, the toner end detection device of this embodiment includes a detection means for detecting the remaining toner state.

It is highly reliable because it is non-contact due to the magnetism between the magnetic piece and the Hall element, it is resistant to toner stains because it is not an optical sensor, and the object to be detected and the detection element are separated both mechanically and electrically. This makes it easy to attach and detach the developing unit.

That is, the operability is excellent.

Furthermore, even if there is a change in characteristics such as temperature drift of the Hall element, the change can be canceled out because relative position is detected. Further, there are advantages such as low overall cost.

〔Effect of the invention〕

As described above, according to the toner end detection device of the present invention, it is possible to provide a toner end detection device that is highly reliable, has excellent operability, and is inexpensive.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a main part of a developing unit equipped with a toner end detection device according to an embodiment of the present invention, FIG. 2 is a side view thereof, and FIG. FIG. 2 is a block diagram showing an example. 1...Developing unit 2a...Upper case 2b...
・Lower case 3...Photoconductor (OPC) Tram 4・
...Developing roller 5...Replenishment roller 6...Blade assembly 7...Agitator assembly 8...Agitator shaft 9...Agitator 10.11...Feeler 12.13...Magnetic material piece 14. ...Toner 1
5.1B...Hall element 17...Detection board 18...Cable 20.21...Comparator 22...NAND circuit diagram 2 procedural amendment (voluntary) July 21, 1999

Claims (1)

[Claims] 1. To a toner stirring mechanism installed in a toner container. At least two fillers having different flexibility are provided to rotate together with the agitator, and a remaining toner state detection means is provided for detecting the remaining toner state by detecting the difference in the amount of deflection of each of the fillers. Toner end detection device. 2. The toner end detection device according to claim 1, wherein each of the fillers has a magnetic piece at a tip, and the remaining toner state detection means has a Hall element for detecting the position of the magnetic piece of each filler. A toner end detection device characterized by: