JPH04230779A - Electrostatic latent image developing device - Google Patents

Abstract

PURPOSE:To have a user appropriately alarmed of the fact when toner particle contained in a toner container is exhausted. CONSTITUTION:The toner particle exhaustion signal generating part 64 indicating that the toner particles contained in the toner particle container is exhausted when the conductivity of the developer inside the developing container is excessively raised and the specified toner particle exhaustion reference value is exceeded is installed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic latent image developing device of the type in which a so-called two-component developer consisting of carrier particles and toner particles is used.

0002

BACKGROUND OF THE INVENTION As is well known to those skilled in the art, in electrostatic copying machines and the like, a so-called two-component developer consisting of carrier particles and toner particles is used as a developing device for developing an electrostatic latent image. BACKGROUND ART Type developing devices have been widely used in practical use. This type of developing device generally includes a developer container containing a developer, a developer application mechanism that holds a portion of the developer in the developer container on the surface and applies it to the electrostatic latent image to be developed. The developer includes a toner particle container for storing toner particles, and a toner particle supply mechanism that is selectively activated to supply toner particles from the toner particle container to the developer in the developer container.

[0003] In the above-mentioned developing device, the toner particle supply mechanism is appropriately operated in accordance with the consumption of toner particles in the developer due to the performance of development, and the toner particles are transferred from the toner particle container to the developer in the developer container. It is important to supply the toner particles appropriately, thus maintaining the ratio of carrier particles to toner particles in the developer in the developer container within the required range. To explain this point in more detail, the developer applying mechanism in the above-mentioned developing device retains the developer consisting of carrier particles and toner particles on its surface, but as is well known to those skilled in the art, the electrostatic latent image is Only the toner particles are deposited and therefore only the toner particles are consumed in carrying out the development, and substantially no carrier particles are consumed. Therefore, if development is repeatedly performed without supplying toner particles to the developer in the developer container, the proportion of toner particles in the developer decreases excessively. In this case, the development density of the developed image decreases, causing problems such as the so-called insufficient development phenomenon. On the other hand,
If excessive toner particles are supplied from the toner particle storage container to the developer in the developer container and the ratio of toner particles in the developer increases excessively, problems such as so-called background-gathering phenomenon occur in the developed image. occurs.

Therefore, conventionally, the ratio of carrier particles to toner particles in the developer in the developer container is detected by various methods, and based on this detection, the toner particle supply mechanism is operated (therefore, the toner particle container is activated). In this way, the ratio of carrier particles to toner particles in the developer in the developer container is maintained within a required range. For example, JP-A-50-12
In the developing device disclosed in Japanese Patent Publication No. 2277 or Japanese Patent Application Laid-open No. 53-119049, there is a correlation between the ratio of carrier particles to toner particles in the developer and the conductivity of the developer (that is, the ratio of toner particles is Focusing on the correlation that the conductivity of the developer increases when the proportion of toner particles decreases, and the conductivity of the developer decreases as the proportion of toner particles increases, the conductivity of the developer in the developer container is detected. Based on this, the operation of the toner particle supply mechanism is controlled.

[0005]

SUMMARY OF THE INVENTION The conventional electrostatic latent image developing apparatus is still not fully satisfactory, and has the following problems to be solved. That is, in the electrostatic latent image developing device described above, the operation of the toner particle supply mechanism is controlled based on the ratio of carrier particles and toner particles in the developer in the developer container, and therefore the operation of the toner particle supply mechanism is controlled. As long as toner particles are accordingly supplied from the toner particle container to the developer in the developer container, the ratio of carrier particles to toner particles in the developer in the developer container can be maintained within the required range. However, when the toner particles contained in the toner particle container itself are exhausted, toner particles are naturally not supplied to the developer in the developer container even if the toner particle supply mechanism is operated. In conventional electrostatic latent image developing devices, even if the toner particles contained in the toner particle container itself are depleted, this is not detected; Development is often carried out without noticing the depletion. In such a case, as development is performed, the ratio of toner particles in the developer in the developer container gradually decreases, and therefore the density of the developed image gradually decreases, resulting in inconveniences such as the so-called insufficient development phenomenon. occurs.

The present invention has been made in view of the above facts, and the technical problem to be solved is that the toner particles contained in the toner particle container itself are exhausted, and therefore, the toner particles are not stored in the toner particle container itself. It is an object of the present invention to provide an improved electrostatic latent image developing device that can detect and alert a user when the need for replenishment arises.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a toner particle supply system that operates a toner particle supply mechanism when the conductivity of a developer exceeds a predetermined toner particle supply reference value. In addition to the toner particle supply signal generating means for generating a signal, when the conductivity of the developer exceeds a predetermined toner particle depletion reference value which is higher than the toner particle supply reference value, the toner contained in the toner particle container itself is activated. Toner particle depletion signal generating means is provided for generating a signal indicating that the particles have been depleted.

That is, according to the present invention, there is provided a developing container containing a developer consisting of carrier particles and toner particles, and an electrostatic latent to be developed by holding a portion of the developer in the developing container on the surface. a developer application mechanism for applying to the image; a toner particle reservoir for containing toner particles; and a toner particle supply selectively actuated to supply toner particles from the toner particle reservoir to the developer in the developer container. a mechanism, a detection means for detecting the conductivity of the developer in the developer container, and when the conductivity of the developer detected by the detection means exceeds a predetermined toner particle supply reference value, the toner particles are removed; and a toner particle supply signal generation means for generating a signal for activating a supply mechanism, wherein the conductivity of the developer detected by the detection means is lower than the toner particle supply reference value. The toner particle depletion signal generating means generates a signal indicating that the toner particles contained in the toner particle container itself are depleted when the toner particle depletion reference value exceeds a high predetermined toner particle depletion reference value. An electrostatic latent image developing device is provided.

[0009]

[Operation] When the toner particles contained in the toner particle container itself are exhausted, even if the toner particle supply signal generating means generates a signal and the toner particle supply mechanism is activated,
Toner particles are no longer supplied to the developer in the developer container,
Therefore, the proportion of toner particles in the developer is reduced excessively, and the conductivity of the developer increases above the toner particle supply reference value. In the electrostatic latent image developing device of the present invention, when the conductivity of the developer increases beyond the toner particle reference value and reaches a predetermined toner particle depletion reference value, the toner particle depletion signal generating means generates a signal. to alert the user that it is necessary to supply toner particles to the toner particle container itself.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an electrostatic latent image developing apparatus constructed in accordance with the present invention will now be described in more detail with reference to the accompanying drawings.

[0011] Referring to FIG. 1, the whole number 2
The illustrated developer device, shown at , comprises a developer housing 8 having a dish-shaped lower plate 4 made of a non-conductive material and an upper cover plate 6 also made of a non-conductive material. A so-called two-component developer 1 consisting of magnetic carrier particles and toner particles is contained in the lower part of the developer housing 8.
A developing container 12 that accommodates 0 is constructed. An opening 14 is formed in the front surface of the developing housing 8, and an opening 18 is formed in the top surface of the developing housing 8, which is closed by a door 16 that can be opened and closed. A developer application mechanism 20 is disposed within the developer housing 8 . Further, inside the developer housing 8, a spike length setting member 22 positioned in relation to and around the developer application mechanism 20, a toner particle container 26 attached with a toner particle supply mechanism 24,
A peeling member 28 and a rotating stirring mechanism 30 are also provided.

Developer application mechanism 20 in the illustrated embodiment
includes a rotary sleeve member 34 that is rotatably mounted and rotationally driven in the direction shown by arrow 32, and a stationary permanent magnet 36 disposed within the rotary sleeve member 34. The stationary permanent magnet 36 is roll-shaped and has six circumferentially spaced magnetic poles on its periphery, ie, three south poles and three north poles located alternately.

[0013] Spiral tone setting member 2 made of conductive material
2 is located with a corner indicated by the number 22a spaced from the surface of the rotary sleeve member 34 preferably at a distance of about 0.5 to 0.3 mm, and as will be mentioned later, The amount of developer 10 held in the magnetic brush, that is, the length of the magnetic brush is set to a required value. The panicle length setting member 22 is arranged at a desired position of the developing housing 8, more specifically, in the lower plate 4, so that the above-mentioned interval can be finely adjusted as needed. It is attached to the front end of the

The toner particle container 26 containing toner particles 38 has a toner particle replenishment opening 40 on the top surface and a toner particle discharge opening 42 on the bottom surface. A toner particle supply mechanism 24 is disposed in the toner particle discharge opening 42 of the toner particle container 26 . The toner particle supply mechanism 24 is composed of a rotatably mounted roller having a large number of recesses or grooves formed on the circumferential surface by, for example, knurling. As will be mentioned later, the toner particle supply mechanism 24 is selectively activated and rotationally driven in the direction indicated by arrow 44, and thus the toner particle supply mechanism 24 is accommodated in a number of recesses or grooves present on the circumferential surface of the toner particle supply mechanism 24. In this state, the toner particles 38 are carried out from the toner particle container 26, and then fall toward the surface of the rotating sleeve member 34, and are supplied to the developer 10 in the developer container 12. Replenishment of the toner particles 38 into the toner particle container 26 itself is as follows:
This is accomplished by opening door 16 on the top surface of developer housing 8 and loading toner particles 38 into toner particle reservoir 26 through opening 18 and toner particle replenishment opening 40 .

The peeling member 28 fixed at a predetermined position within the developer housing 8 has a tip 28a that contacts or approaches the surface of the rotating sleeve member 34. By acting on the developer 10 present on the surface, the developer 10 is reliably peeled off from the surface of the rotating sleeve member 34.

The rotary agitation mechanism 30 is composed of a rotary agitation member that is rotatably mounted and rotated in the direction shown by an arrow 46.

The developing device 2 as described above is disposed on the circumferential surface of a rotating drum 48 (only a portion of which is shown), which is rotatably mounted in, for example, an electrostatic copying machine housing (not shown). Toner particles are applied to an electrostatic latent image formed on an electrostatographic photoreceptor 50 (also only a portion of which is shown) by any suitable method which is well known per se, and this is developed into a visible image. It is used as a developing device for In this case, in the developing device 2, as shown in FIG.
It is installed so that it is positioned facing the The developing device 2 performs the following operations in accordance with the rotation of the rotating sleeve member 34 in the direction indicated by the arrow 32. First, in the developer drawing-up area indicated by the symbol P, the developer 10 present in the developer container 12 is pulled up by the magnetic attraction force of the permanent magnet 36.
is attracted and held on the surface of the rotating sleeve member 34, thus forming a magnetic brush 52 of the developer 10 on the surface of the rotating sleeve member 34. Next, the magnetic brush 52 is made to have a desired length by the action of the brush length setting member 22. Thereafter, in a developing area indicated by the symbol D, the magnetic brush 52 is brought into contact with the surface of the photoreceptor 50 which is being rotated in the direction indicated by the arrow 54,
The toner particles in the magnetic brush 52 are applied to the electrostatic latent image thus formed on the photoreceptor 50, and the electrostatic latent image is developed into a visible image. Next, in the developer stripping region indicated by symbol R, in this developer stripping region R, the magnetic pole of the permanent magnet 36 does not exist, and even if the magnetic field exists, it is extremely small, and in addition, the stripping member 28 rotates. Rotating sleeve member 34 by acting on magnetic brush 52 on sleeve member 34
The developer 10 forming the magnetic brush 52 is peeled off from the surface. The peeled developer 10 flows down along the upper surface of the peeling member 28 and falls toward the rotating stirring mechanism 30. The rotary stirring mechanism 30 stirs the developer 10 to uniformly mix the carrier particles and toner particles in the developer 10, and also triboelectrically charges the toner particles, for example, negatively.

Therefore, the above-described configuration and operation of the illustrated developing device 2 do not constitute a new improvement of the developing device configured according to the present invention, but rather a developing device to which the present invention is applied. It is merely an example of this.

Continuing the explanation with reference to FIG. 1, the electrical conductivity of the developer 10 in the developer container 12 in the developing device 2 (this electrical conductivity also includes the influence of the charge in the developer 10 due to triboelectric charging)
is equipped with detection means for detecting. In the illustrated embodiment, a voltage source 56 is electrically interposed between the rotary sleeve member 34 of the developer application mechanism 20 and ground, and the spike length setting member 22 is formed of a conductive material. is also used as a counter electrode. The voltage source 56 applies a DC voltage of, for example, about 200V to the rotating sleeve member 34. And the rotating sleeve member 3
The electrical conductivity of the developer 10 in the developer container 12 is detected by detecting the current flowing between the developer 10 and the brush length setting member 22 through the developer 10 present therebetween.

In the illustrated embodiment, a rotating drum 48 made of a conductive material and having a photoreceptor 50 disposed on its circumferential surface is grounded. Therefore, the voltage source 5
6 functions as a voltage source for detecting the conductivity of the developer 10 in the developer container 12, and also prevents the occurrence of so-called background fog during development between the rotating sleeve member 34 and the photoreceptor 50 in the development area D. It also functions as a development bias voltage source that applies a development bias voltage which itself is well known.

The counter electrode for detecting the current flowing through the developer 10 in the developer container 12 may be composed of another appropriate member instead of being composed of the spike length setting member 22 as described above. You can also do it. For example, as shown in FIG. 2, a conductive member 58 may be embedded in the upper surface of the dish-shaped lower plate 4 defining the bottom surface of the developer container 12, and the conductive member 58 may constitute a counter electrode. Further, depending on the case, the dish-shaped lower plate 4 itself may be formed from a conductive material, and the dish-shaped lower plate 4 itself may be used as a counter electrode. Furthermore, the above-mentioned Japanese Patent Application Laid-open No. 50-12
As disclosed in Japanese Patent No. 2277, a conductive member may be disposed at an appropriate position within the developer container 12, and the counter electrode may be constituted by such a conductive member. However, in this case, the flow of the developer 10 within the developer container 12 may be inhibited by the conductive material constituting the counter electrode, which may have some adverse effect on the performance of development.

In the embodiment shown in FIG. 1, the counter electrode constituted by the panicle length setting member 22 is filtered via a noise filter 60, which is well known per se and which can consist, for example, of an integrating circuit. It is electrically connected to each of the toner particle supply signal generation means 62, toner particle depletion signal generation means 64, and carrier particle deterioration signal generation means 66 described above. Therefore, the current flowing between the rotary sleeve member 34 and the brush length setting member 22 through the developer 10 present therebetween is transmitted to the toner particle supply signal generating means 62 after the noise is eliminated by the noise filter 60. The signal is supplied to each of a toner particle depletion signal generating means 64 and a carrier particle deterioration signal generating means 66.

The toner particle supply signal generating means 62 has a first input terminal connected to the panicle length setting member 22 via a noise filter 60 and a second input terminal connected to a reference voltage source 68. It consists of a comparator. The toner particle supply signal generating means 62 converts the current supplied to the first input terminal into a voltage, and converts the current supplied to the first input terminal into a reference voltage (V1) from the reference voltage source 68 supplied to the second input terminal.
), and when the former is greater than or equal to the latter, a signal is generated at its output terminal.

As disclosed in JP-A-50-122277, the electrical conductivity of toner particles is lower than that of carrier particles, and therefore the proportion of toner particles in developer 10 in developer container 12 is lower than that of carrier particles. If the ratio of toner particles decreases, the conductivity of the developer 10 increases, and conversely, if the ratio of toner particles increases, the conductivity of the developer 10 decreases. Therefore, when the toner particles in the developer 10 in the developer container 12 are consumed by performing development and the proportion of toner particles in the developer 10 decreases,
The current supplied to the first input of the toner particle supply signal generating means 62 increases. On the other hand, the reference voltage (V1) of the reference voltage source 68 indicates the conductivity of the developer 10 when the ratio of toner particles in the developer 10 in the developer container 12 increases to a value at which toner particles should be supplied to the developer 10. This is set to a value corresponding to the toner particle supply reference value, which is the toner particle supply rate. As described above, when the conductivity of the developer 10 in the developer container 12 becomes equal to or higher than the toner particle supply reference value and toner particles should be supplied to the developer 10, the toner particle supply signal generating means 62 A signal or toner particle supply signal is generated at the output terminal of the toner particle supply signal.

The toner particle supply signal is supplied to a control circuit 70 for controlling the operation of the toner particle supply mechanism 24. When the toner particle supply signal is supplied to the control circuit 70, the toner particle supply mechanism 24 is operated for a time interval corresponding to the existence time interval of the toner particle supply signal or a predetermined time interval that is appropriately set. The electric motor 72 is energized to rotate the toner particle supply mechanism 24 in the direction indicated by the arrow 44, thereby supplying the toner particles 38 in the toner particle container 26 to the developer 10 in the developer container 12. be done.

As described above, the operation of the toner particle supply mechanism 24 is controlled based on the ratio of toner particles in the developer 10 in the developer container 12, and therefore, the operation of the toner particle supply mechanism 24 is controlled according to the operation of the toner particle supply mechanism 24. As long as the toner particles 38 in the particle reservoir 26 are properly supplied to the developer 10;
The proportion of toner particles in developer 10 is maintained within the required range. However, when the toner particles 38 contained within the toner particle container 26 itself are depleted, even if the toner particle supply mechanism 24 is activated, the developer 10
The toner particles 38 are not supplied to the developer 10, and the ratio of toner particles in the developer 10 is excessively reduced beyond the required range.

In the illustrated developing device 2 constructed according to the present invention, the toner particles 38 contained in the toner particle container 26 itself are exhausted, and the proportion of toner particles in the developer 10 is reduced. If the toner particle depletion signal decreases excessively beyond the required range, the toner particle depletion signal generating means 64 generates a signal.

To be more specific, the toner particle depletion signal generating means 64 transmits the toner particle depletion signal to the spike length setting member 22 via the noise filter 60.
and a second input terminal connected to a reference voltage source 74. The toner particle depletion signal generating means 64
converts the current supplied to the first input terminal into a voltage and compares it with the reference voltage (V2) from the reference voltage source 74 supplied to the second input terminal, and if the former exceeds the latter, the voltage is Generate a signal at the output terminal.

When the toner particles 38 contained within the toner particle container 26 itself are depleted, the proportion of toner particles in the developer 10 decreases excessively beyond the required range, as described above. Accordingly, the conductivity of the developer material 10 increases excessively and the current supplied to the first input of the toner particle depletion signal generating means 64 increases excessively. On the other hand, the reference voltage source 74
The reference voltage (V2) is equal to the reference voltage (V1) of the reference voltage source 68 associated with the toner particle supply signal generating means 62 described above.
), and is set to a value corresponding to a toner particle depletion reference value, which is the conductivity of the developer 10 when the ratio of toner particles in the developer 10 is excessively reduced. As described above, when the toner particles 38 contained in the toner particle container 26 itself are depleted and the conductivity of the developer 10 increases excessively and exceeds the toner particle depletion reference value, toner particle depletion occurs. A signal or toner particle depletion signal is generated at the output terminal of the signal generating means 64.

The toner particle depletion signal is provided to a suitable alarm 76, such as a warning light or an audible alarm, so that the toner particles 38 within the toner particle container 26 are depleted and the toner particles 38 within the toner particle container 26 itself are depleted. The user is alerted that the need to replenish toner particles 38 has occurred.

As mentioned above, the carrier particles in the developer 10 in the developer container 12 are damaged due to the fact that when development is repeatedly carried out over a long period of time, the toner particles attached to the carrier particles cannot be separated. to degrade. When carrier particles deteriorate, development quality inevitably deteriorates.

In the illustrated embodiment constructed in accordance with the present invention, when the carrier particles in the developer 10 deteriorate and it becomes necessary to replace the carrier particles, the carrier particle deterioration signal generating means 66 is activated. Generate a signal.

To be more specific, the carrier particle deterioration signal generating means 66 transmits the signal to the ear length setting member 2 via the noise filter 60.
2 and a second input terminal connected to a reference voltage source 78. The carrier particle deterioration signal generating means 66 converts the current supplied to the first input terminal into a voltage, and converts the current supplied to the first input terminal into a reference voltage (V3) from the reference voltage source 78 supplied to the second input terminal. When the former is less than or equal to the latter, a signal is generated at the output terminal.

When the carrier particles in the developer 10 in the developer container 12 deteriorate due to reasons such as the inability of the toner particles attached thereto to separate, the conductivity of the developer 10 decreases excessively. The conductivity approaches that of toner particles alone. Therefore, the current supplied to the carrier particle deterioration signal generating means 66 decreases excessively. On the other hand, the reference voltage (V3) of the reference voltage source 78 is lower than the reference voltage (V1) of the reference voltage source 68 related to the toner particle supply signal generating means 62 by a predetermined amount or more, and the carrier particles in the developer 10 are The carrier particle deterioration reference value is set to a value corresponding to the carrier particle deterioration reference value, which is the conductivity of the developer 10 when the carrier particles have deteriorated and it becomes necessary to replace the carrier particles. As shown above, developer 1
When the carrier particles in the developer 10 deteriorate and it becomes necessary to replace the carrier particles, and as a result, the conductivity of the developer 10 excessively decreases to below the carrier particle deterioration reference value, the carrier particle deterioration signal generating means 66 A signal, namely a carrier particle degradation signal, is generated at the output terminal.

The carrier particle deterioration signal is provided to a suitable warning device 80, such as a warning lamp or an audible alarm;
In this way, the user is warned that the carrier particles in the developer 10 in the developer container 12 have deteriorated and that the carrier particles need to be replaced.

If desired, for example, a carrier particle container (not shown) for storing carrier particles in the upper part of the developer housing 8 and the carrier particles in this carrier particle container can be added to the developer 10 in the developer container 12. A carrier particle supply mechanism (not shown) is attached to supply the carrier particles, and when the carrier particle deterioration signal is generated, the carrier particle supply mechanism is operated in response to the carrier particle deterioration signal to remove the carrier particles in the carrier particle container. It is also possible to supply the carrier particles to the developer 10 in the developer container 12 to temporarily suppress deterioration in development quality until the carrier particles in the developer 10 are replaced with new carrier particles.

FIG. 3 illustrates a modification of the carrier particle deterioration signal generating means. The carrier particle deterioration signal generating means 66A shown in FIG. 3 is composed of a counter having two input terminals and one output terminal. One of the two input terminals is connected to the output terminal of the toner particle supply signal generation means 62 as described above, and when the toner particle supply signal generation means 62 generates the toner particle supply signal at its output terminal, such The toner particle supply signal is supplied to the above-mentioned control circuit 70 and also to one input terminal of the carrier particle deterioration signal generating means 66A. The other of the two input terminals is connected to the output terminal of a signal generator 82 which generates a signal each time development of the electrostatic latent image is performed by the development device 2. When the developing device 2 is incorporated in a normal electrostatic copying machine, the development of the electrostatic latent image by the developing device 2 is performed every time a copying process is performed by the electrostatic copying machine. 82, which detects and generates a signal each time the document table (or at least part of the optical system) is moved as required, for example, for scanning exposure of the document to be copied. A copy count detector can be used. The carrier particle deterioration signal generation means 66A, which is constituted by a counter, counts the signal supplied from the signal generator 82, but is reset when the toner particle supply signal is supplied from the toner particle supply signal generation means 62. Then, when n is counted, which may be 15, for example, without being reset, a carrier particle deterioration signal is generated at the output terminal.

When the electrostatic latent image is developed as described above, the toner particles in the developer 10 in the developer container 12 are consumed by being applied to the electrostatic latent image, and the toner particles in the developer 10 are consumed. The percentage of Therefore, when at least several development cycles are carried out repeatedly, the proportion of toner particles in the developer material 10 decreases considerably, and in the normal case, the conductivity of the developer material 10 increases to a certain extent that said toner particles The particle supply reference value is exceeded, so the toner particle supply signal generating means 62
generates a toner particle supply signal. However, when the carrier particles in the developer 10 deteriorate and it becomes necessary to replace the carrier particles, the conductivity of the developer 10 decreases considerably due to the deterioration of the carrier particles as described above. In such a case, even if the development of the electrostatic latent image is repeated n times and the proportion of toner particles in the developer 10 decreases considerably, the conductivity of the developer 10 due to the decrease in the proportion of toner particles will decrease. The increase is offset by a decrease in the conductivity of the developer 10 due to deterioration of the carrier particles, and the conductivity of the developer 10 does not exceed the toner particle supply reference value. Therefore, the development of the electrostatic latent image is n
Even if performed repeatedly, the toner particle supply signal generating means 62 does not generate a toner particle supply signal during that time, and thus the carrier particle deterioration signal generating means 66A generates a carrier particle deterioration signal at its output terminal.

The carrier particle deterioration signal generated by the carrier particle deterioration signal generating means 66A is similar to the carrier particle deterioration signal generated by the carrier particle deterioration signal generating means 66 shown in FIG. Thus, the user is warned that the carrier particles in the developer 10 in the developer container 12 have deteriorated and that the carrier particles need to be replaced.

The carrier particle deterioration signal generating means 66A shown in FIG. 3 is superior to the carrier particle deterioration signal generating means 66 shown in FIG. 1 in the following points. That is, when the developing device 2 is not used for a long period of time and is stopped,
The charge in the developer 10 due to triboelectric charging has been considerably dissipated, due to which the carrier particles have not deteriorated and the proportion of toner particles in the developer 10 has not increased excessively. , the conductivity of the developer 10 may decrease and become below the carrier particle deterioration reference value. Therefore,
In the case of the carrier particle deterioration signal generating means 66 shown in FIG. It is possible to erroneously generate a particle degradation signal. Of course, the erroneously generated carrier particle deterioration signal is removed when the electrostatic latent image is developed once the use is restarted, and at this time, the developer 10 is triboelectrically charged by the stirring action of the rotary stirring mechanism 30, and thus the developer 10 It disappears when the conductivity returns to its normal value. On the other hand, Figure 3
The carrier particle deterioration signal generating means 66A shown in FIG. Therefore, there is no risk of erroneously generating a carrier particle deterioration signal even when the device is restarted after being left unused for a long period of time.

Although the embodiments of the electrostatic latent image developing device constructed according to the present invention have been described above in detail with reference to the accompanying drawings, the present invention is not limited to such embodiments, and the present invention is not limited to such embodiments. It goes without saying that various modifications and modifications can be made without departing from the scope.

[0042]

[Effect of the invention] In the electrostatic latent image developing device of the present invention,
When the toner particles contained in the toner particle container are depleted and the conductivity of the developer in the developer container increases excessively, the toner particle depletion signal generating means generates a signal to remove the toner particles from the toner particle container itself. Alerts the user that it is necessary to replenish. Therefore, it is reliably prevented that development is repeatedly performed without noticing the depletion of toner particles contained in the toner container, resulting in the so-called insufficient development phenomenon.

[Brief explanation of the drawing]

FIG. 1 is a simplified diagram showing an embodiment of an electrostatic latent image developing device constructed according to the present invention, partly in cross-section and partly in block diagram form.

FIG. 2 is a simplified cross-sectional view showing a modification of the counter electrode.

FIG. 3 is a simplified partial block diagram showing a modification of carrier particle deterioration signal generation means.

[Explanation of symbols]

2: Electrostatic latent image developing device 10: Developer 12: Developing container 20: Developer application mechanism 22: Panicle length setting member (counter electrode) 24: Toner particle supply mechanism 26: Toner particle container 38: Toner particles 56: Voltage source 58: Conductive member (counter electrode) 62: Toner particle supply signal generation means 64: Toner particle depletion signal generating means 66: Carrier particle deterioration signal generation means

Claims (6)

[Claims] 1. A developer container containing a developer consisting of carrier particles and toner particles, and a developer that retains a portion of the developer in the developer container on its surface and applies it to an electrostatic latent image to be developed. an application mechanism, a toner particle reservoir containing toner particles, a toner particle supply mechanism selectively actuated to supply toner particles from the toner particle reservoir to the developer in the developer container; and the developer container. a detection means for detecting the conductivity of the developer in the detector, and when the conductivity of the developer detected by the detection means exceeds a predetermined toner particle supply reference value;
In an electrostatic latent image developing device comprising a toner particle supply signal generation means for generating a signal for operating the toner particle supply mechanism, the conductivity of the developer detected by the detection means is the toner particle supply reference. and a toner particle depletion signal generating means for generating a signal indicating that the toner particles contained in the toner particle container itself are depleted when the toner particle depletion reference value exceeds the predetermined toner particle depletion reference value.
An electrostatic latent image developing device characterized by: 2. When the electrical conductivity of the developer detected by the detection means falls below a predetermined carrier particle deterioration reference value that is lower than the toner particle supply reference value, it is determined that the carrier particles in the developer have deteriorated. 2. The electrostatic latent image developing device according to claim 1, further comprising carrier particle deterioration signal generating means for generating a signal indicating the carrier particle deterioration signal. 3. If the toner particle supply signal generating means does not continue to generate the signal even though development of the electrostatic latent image has been repeatedly performed a predetermined number of times, carrier particles in the developer have deteriorated. 2. The electrostatic latent image developing device according to claim 1, further comprising carrier particle deterioration signal generating means for generating a signal indicative of the carrier particle deterioration. 4. The detection means includes a voltage source that applies a predetermined voltage to the developer application mechanism, and a counter electrode positioned opposite to the developer application mechanism with the developer sandwiched therebetween. An electrostatic latent image developing device according to any one of claims 1 to 3. 5. The electrostatic latent image developing device according to claim 4, wherein the counter electrode comprises a brush length setting member for setting the amount of developer held on the surface of the developer application mechanism. Device. 6. The counter electrode is composed of a member defining at least a part of the bottom surface of the developer container.
The electrostatic latent image developing device according to claim 4.