JPH0578031B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electrostatic latent image developing device, and more particularly 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. As is well known to those skilled in the art, in electrostatic copying machines and the like, as a developing device for developing an electrostatic latent image,
2. Description of the Related Art Developing devices using a so-called two-component developer consisting of carrier particles and toner particles have been widely put into 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 toner particle container includes a toner particle container for storing toner particles, and a toner particle supply means that is selectively operated to supply toner particles from the toner particle container to the developer in the developer container. In the above-mentioned developing device, the toner particle supply means is appropriately operated to supply toner particles from the toner particle container to the developer in the developer container in accordance with the consumption of toner particles in the developer due to the performance of development. death,
Thus, it is important to maintain 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 developer applying mechanism in the above-mentioned developing device holds the developer consisting of carrier particles and toner particles. 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,
When 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 fogging occur in the developed image. occurs. Therefore, in the past, 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 means is activated (therefore, the toner particle container is activated). supply of toner particles from to the developer in the developer container)
is controlled, thus maintaining the ratio of carrier particles to toner particles in the developer in the developer container within a required range. However, the conventional developing device is still not fully satisfactory and has the following drawbacks and problems. That is, in the above-described developing device, the ratio of carrier particles to toner particles in the developer in the developer container is detected and the operation of the toner particle supply mechanism is controlled based on the detected signal. Since its operation is controlled only by the ratio of carrier particles to toner particles in the developer, there is a relatively wide range in the ratio of carrier particles to toner particles (i.e., a good toner image is obtained). (the ratio of carrier particles to toner particles in the developer container is controlled over a relatively large range with respect to the desired ratio that can yield the ratio of carrier particles to toner particles in the developer). cannot be maintained precisely within the required range. This is because when the ratio of carrier particles to toner particles, that is, the toner concentration, falls below a predetermined value, the toner particle supply means is activated, and the toner particles supplied by the operation of the toner particle supply means become carrier particles. This is because it takes time for the toner to be mixed and used as a developer, and the toner concentration decreases during this time. The present invention has been made in view of the above facts, and an object of the present invention is to provide an improved developing device that can maintain the ratio of carrier particles of developer and toner particles in a developer container at a required ratio. It is to be. According to the present invention, there is provided a developer container that contains a developer consisting of carrier particles and toner particles, and a developer that retains a portion of the developer in the developer container on the surface and applies it to an electrostatic latent image to be developed. a toner particle reservoir for containing toner particles; a toner particle supply means that is selectively actuated to supply toner particles from the toner particle reservoir into the developer container; An electrostatic latent comprising: a toner concentration detection means for detecting the toner concentration in the developer; and a control means for controlling the operation of the toner particle supply means based on the toner concentration value detected by the toner concentration detection means. In the image developing device; the control means compares the toner concentration value detected by the toner concentration detection means with a predetermined reference value to calculate a comparison relationship between the two, and also controls the fluctuation state of the toner concentration value detected by the toner concentration detection means. When the detected toner concentration value is larger than a predetermined reference value, the toner particle supply means is deactivated, and when the detected toner concentration is smaller than the predetermined reference value, the toner particle supply means is activated, and the detected toner concentration is There is provided an electrostatic latent image developing device characterized in that the toner particle supply means is controlled in operation when the fluctuation state of the detected toner concentration value tends to decrease even when the value is substantially equal to a predetermined reference value. Hereinafter, preferred embodiments of the electrostatic latent image developing device constructed according to the present invention will be described in more detail with reference to the accompanying drawings. Referring to FIG. 1, the illustrated electrostatic latent image development device, generally designated by the numeral 2, includes a dish-shaped lower plate 4 formed from a non-conductive material as well as a dish-shaped lower plate 4 formed from a non-conductive material. A developing housing 8 having an upper cover plate 6 is provided. The lower part of the developer housing 8 constitutes a developer container 12 containing a so-called two-component developer 10 consisting of magnetic carrier particles and toner particles. Developing housing 8
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 provided within the developer housing 8.
is installed. Further, inside the developer housing 8, a spike length setting member 22 positioned in relation to the developer application mechanism 20 and a toner particle container 2 provided with a toner particle supply means 24 are provided.
6. A peeling member 28 and a rotating stirring mechanism 30 are also provided. The developer application mechanism 20 in the illustrated example includes:
The rotary sleeve member 34 is rotatably mounted and rotationally driven in the direction shown by an arrow 32, and a stationary permanent magnet 36 is 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. Ear length setting member 22 made of conductive material
In this case, the corner indicated by number 22a is the rotating sleeve member 3.
The developer 1 is positioned at a distance of preferably about 0.5 to 3.0 mm from the surface of the rotary sleeve member 4, and is held on the surface of the rotating sleeve member 34, as will be described later.
The amount of 0, ie, the length of the magnetic brush tip, is set to a required value.
The panicle length setting member 22 is configured such that, for example, the first
In the figure, it is mounted at a desired position of the developing housing 8, more specifically at the front end of the lower plate 4, so that its position in the left and right direction can be finely adjusted. Toner particle container 2 containing toner particles 38
6 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 means 24 is disposed in the toner particle discharge opening 42 of the toner particle container 26 . The toner particle supply means 24 is constituted by a rotatably mounted roller, the circumferential surface of which is provided with a number of recesses or grooves, for example, by knurling. As will be mentioned later, the toner particle supply means 24 is selectively actuated and driven to rotate in the direction indicated by arrow 44, so that the toner particle supply means 24 is accommodated in a number of recesses or grooves present on the circumferential surface of the toner particle supply means 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 to be transferred to the developer container 12.
The developer 10 is supplied to the developer 10 inside. To replenish the toner particle container 26 itself with toner particles 38, open the door 16 provided on the top surface of the developer housing 8.
This is accomplished by 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, and as mentioned later, the tip 28a is present on the surface of the rotating sleeve member 34. By acting on the developer 10, the developer 10 is removed from the surface of the rotating sleeve member 34.
Make sure to remove it. The rotary agitation mechanism 30 is comprised of a rotary agitation member that is rotatably mounted and rotationally driven in the direction indicated by an arrow 46 . The developing device 2 as described above is, for example, an electrostatic copying machine provided on the circumferential surface of a rotating drum 48 (only a portion of which is shown) rotatably mounted in an electrostatic copying machine housing (not shown). Electrophotographic photoreceptor 50
(Similarly, only a portion of the image is shown) is used as a developing device for applying toner particles to an electrostatic latent image formed by an appropriate method known per se to develop this into a visible image. used. In this case,
The developing device 2 is mounted so that the opening 14 formed in the front surface of the developing housing 8 faces the photoreceptor 50, as shown in FIG. 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 attracted and held on the surface of the rotating sleeve member 34 by the magnetic attraction force of the permanent magnet 36, and thus the rotating sleeve A magnetic brush 52 of developer 10 is formed on the surface of 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 symbol D, the magnetic brush 52 is brought into contact with the surface of the photoconductor 50 which is being rotated in the direction indicated by the arrow 54, and the electrostatic charge thus formed on the photoconductor 50 is removed. Toner particles in magnetic brush 52 are applied to the latent image 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. By acting on the magnetic brush 52 on the sleeve member 34, the developer 10 forming the magnetic brush 52 is peeled off from the surface of the rotating sleeve member 34. The peeled developer 10 is removed by the peeling member 2
The liquid flows down along the upper surface of the rotary stirring mechanism 30 and falls toward the rotating stirring mechanism 30. The rotary stirring mechanism 30 rotates the developer 1
0 is stirred to uniformly mix the carrier particles and toner particles in the developer 10 and to triboelectrically charge 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 are merely improvements in the developing device to which the present invention is applied. This is merely an example. Continuing the explanation with reference to FIG. 1, the developing device 2
is equipped with a detection means for detecting the toner concentration by detecting the electrical conductivity of the developer 10 in the developer container 12 (this electrical conductivity also includes the influence of the charge in the developer 10 due to triboelectric charging). In the illustrated embodiment, the rotary sleeve member 3 of the developer application mechanism 20
A voltage source 56 is electrically interposed between 4 and ground, and the above-mentioned spike length setting member 22 made of a conductive material is also used as a counter electrode. The voltage source 56 applies a DC voltage, which may be about 200V, to the rotating sleeve member 34, for example. Then, the rotating sleeve member 34 and the ear length setting member 22
By detecting the current flowing through the developer 10 existing between the developer container 12 and
The conductivity of the developer material 10 within is detected. In the illustrated example, 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 56 functions as a voltage source for detecting the conductivity of the developer 10 in the developer container 12, and also serves as a voltage source for detecting the conductivity of the developer 10 in the developer container 12. It also functions as a developing bias voltage source that applies a well-known developing bias voltage to prevent the occurrence of so-called background fog. The counter electrode for detecting the current flowing through the developer 10 in the developer container 12 may be composed of other appropriate members instead of being composed of the spike length setting member 22 as described above. for example,
An electrically conductive member may be embedded in the upper surface of the dish-shaped lower plate 4 that defines the bottom surface of the developer container 12, and the counter electrode may be constituted by the electrically conductive member. 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. In the above specific example, the counter electrode constituted by the panicle length setting member 22 is controlled via a noise filter (not shown), which is well known per se and which can be constituted by an integrating circuit, for example, as described in detail below. It is electrically connected to means 58 . Therefore, a toner concentration detection signal based on the detected toner concentration value detected by the toner concentration detection means is supplied to the control means 58. The control means 58, which is constituted by a microprocessor, for example, includes first memory means 60, second memory means 62, third memory means 64, fourth memory means 66, and timing pulse generation means 68. . The first memory means 60 stores a detected toner density value based on the toner density detection signal supplied from the toner density detection means to the control means 58. The second memory means 62 stores the detected toner concentration value detected by the toner detection means a predetermined period ago, as will be explained in detail later. The third memory means 64 stores a required ratio of carrier particles to toner particles in the developer, that is, a predetermined reference value of toner concentration. Also, the fourth
The memory means 66 includes "high speed", "medium speed" and "low speed" for operating the electric motor 70 as described above for rotating the toner particle supply means 24 in the direction indicated by the arrow 44. Data is stored. Furthermore, timing pulse generation means 6
8 generates pulse signals at predetermined intervals (for example, at intervals of 0.5 seconds to 1 second). This pulse signal serves to supply a toner concentration detection signal from the toner concentration detection means to the control means 58 at predetermined intervals. As will be described in detail later, the control means 58 controls the detected toner concentration value based on the toner concentration detection signal from the toner concentration detection means (in the specific example, the detected toner concentration value stored in the first memory means 60). A predetermined reference value (in the specific example, the third memory means 64
A comparison relationship between the two is calculated by comparing the toner density with a predetermined reference value of toner density stored in is the detected toner concentration value based on the toner concentration detection signal from the previous toner concentration detection means (corresponding to the interval of pulse signals generated by the timing pulse generation means 68) (in the specific example, the second memory means 62 (Detected toner density value stored in )
By comparing the comparison relationship between the two, the fluctuation state of the toner concentration value detected by the toner concentration detection means is calculated, and the electric motor 70 is controlled as described later based on the comparison relationship and the fluctuation state. Generates an activation signal for activation. That is, when "high speed" (or "medium speed", "low speed") data is read out from the fourth memory means 66 based on the above comparison relationship and the above fluctuation state, the "high speed" (or "medium speed") data is read out from the fourth memory means 66 based on the above comparison relationship and the above fluctuation state. ”, “low speed”) data, a high speed actuation signal (or medium speed actuation signal, low speed actuation signal) is generated,
This high speed operation signal (or medium speed operation signal, low speed operation signal) is sent to the electric motor 70. When a high-speed operation signal is sent from the control means 58, the electric motor 70 is driven to rotate at a predetermined high speed, and the toner particle supply means 24 is thus rotated at a relatively high speed to supply a relatively large amount of toner particles to the developer container 12. (a large amount of supply occurs). When a low speed actuation signal is sent from the control means 58, the electric motor 70
is rotated at a predetermined low speed, and thus the toner particle supply means 24 is rotated at a relatively low speed to supply a relatively small amount of toner particles into the developer container 12 (a small amount supply state). Further, when a medium speed operation signal is sent from the control means 58, the electric motor 70 is driven to rotate at a predetermined medium speed between the predetermined high speed and the predetermined low speed, and thus the toner particle supply means 24 is rotated. It is rotated at a medium speed to supply toner particles into the developer container 12 that are less than a relatively large amount and more than a relatively small amount. (This results in an intermediate supply state in which a larger amount of toner particles is supplied than the supply amount.) The table shows the detected toner concentration value from the toner concentration detection means (the detected toner concentration value M ₁ stored in the first memory means 60) and the predetermined reference value of toner concentration (the detected toner concentration value M 1 stored in the third memory means 64). the comparison relationship with the predetermined reference value M ₃ ) detected by the toner concentration detection means (the detected toner concentration value M ₁ stored in the first memory means 60) and the toner concentration detected a predetermined period before. Fluctuations in the toner concentration value detected by the toner concentration detection means obtained by calculating a comparison relationship with the toner concentration value detected from the means (the detected toner concentration value M ₂ stored in the second memory means 64) state and the control means 58
The relationship with the control of the electric motor 70 operated by the operation signal generated in the figure is shown.

[Table] Next, to explain the above relationship mainly with reference to the above table, the toner concentration value (M ₁ ) detected by the toner concentration detection means is the predetermined reference value (M ₃ ) of the toner concentration.
(M ₁ >M ₃ ), and the toner concentration value (M ₁ ) detected by the toner concentration detection means is substantially equal to the predetermined reference value (M ₃ ) (M ₁ =M ₃ ), and When the toner concentration value (M ₂ ) detected by the toner concentration detection means before the period is larger (M ₁ > M ₂ ) or substantially equal to the detected toner concentration value (M ₂ ) (M ₁ =M ₂ ), an activation signal is generated. is not generated, the electric motor 70 becomes inactive, and the toner particle supply means 24 becomes inactive (therefore, the supply is stopped). The toner concentration value (M ₁ ) detected by the toner concentration detection means is substantially equal to the predetermined reference value (M ₃ ) (M ₁ =M ₃ ), and the toner concentration value (M ₂ ) detected by the toner concentration detection means before the predetermined period of time is ) (M ₁ <M ₂ ), and the toner concentration value (M ₁ ) detected by the toner concentration detection means is smaller than the predetermined reference value (M ₃ ) (M ₁ <M ₃ ) and for a predetermined period of time. Toner concentration value detected by the previous toner concentration detection means (M ₂ )
(M ₁ >M ₂ ), the "slow" data is read from the fourth memory means 66 and a slow actuation signal is generated in the control means 58, thus causing the toner particle supply means 24 to operate as described above. It is rotated at a relatively low speed (thus providing a small volume supply). Further, if the toner concentration value (M ₁ ) detected by the toner concentration detection means is smaller than the predetermined reference value (M ₃ ) (M ₁ <M ₃ ) and the toner concentration value (M 1 ) detected by the toner concentration detection means before the predetermined period, ₂ ), the "medium speed" data is read from _the fourth memory means 66 and a medium speed actuation signal is generated in the control means 58 _, thus causing the toner particle supply means to 24 is rotated at medium speed as described above (therefore, in an intermediate supply state). Further, if the toner concentration value (M ₁ ) detected by the toner concentration detection means is smaller than the predetermined reference value (M ₃ ) (M ₁ <M ₃ ) and the toner concentration value (M 1 ) detected by the toner concentration detection means before the predetermined period of time is ₂ ) (M ₁ <M ₂ ), then "high speed" data is read from the fourth memory means 66 and a high speed actuation signal is generated in the control means 58, thus causing the toner particle supply means 24 to As mentioned above, it is rotated at a relatively high speed (therefore, a large amount is supplied). Next, further explanation will be given with reference to FIG. 2, which shows a flowchart of the control of the control means 58. First, in step n-1, a toner concentration detection signal from the toner concentration detection means is input to the control means 58. The input of such a signal is as described above.
This is done in synchronization with the pulse signal generated by the timing pulse generating means 68, thus at intervals of 0.5 to 1 second in the specific example. When the toner concentration detection signal is input, the process moves to step n-2, and the detected toner concentration value based on the toner concentration detection signal is stored in the first memory means 60. Next, the process moves to step n-3, where the detected toner concentration value (M ₁ ) stored in the first memory means 60 is stored.
and a predetermined reference value (M ₃ ) stored in the third memory means 64. In step n-3, it is determined that the toner concentration value (M ₁ ) detected by the first memory means 60 is larger than the predetermined reference value (M ₃ ) of the third memory means 64 (M ₁ >M ₃ ). In this case, the process moves to step n-4, where the control means 58 does not generate an actuation signal for actuating the electric motor 70, and in step n-5, the electric motor 70 is deactivated (thus, the toner particles The supply means 24 is in a supply stop state). In step n-3, the toner concentration value (M ₁ ) detected by the first memory means 60 is compared and determined to be substantially equal to the predetermined reference value (M ₃ ) of the third memory means 64 (M ₁ =M ₃ ). If the detected toner density value (M 1 ) is stored in the first memory means 60 and the detected toner density value (M ₂ ) is stored in the second memory means 62, the process moves to step n- ₆ . )
(As described above, this detected toner density value is the detected toner density value detected by the toner density detection means a predetermined period ago.) (calculating the fluctuation state of the toner density value detected by the density detection means). In step n-6, it is determined that the toner concentration value (M ₁ ) detected by the first memory means 60 is smaller than the toner concentration value (M ₂ ) detected by the second memory means 62 (M ₁ <M ₂ ). If so, proceed to step n-7, and in step n-7
Among the "high speed", "medium speed", and "low speed" data stored in the memory means 66 of , "low speed" data is read out. When "slow" data is read,
The process moves to step n-8, in which the control means 58 generates a low-speed operation signal based on the "low speed" data, and then the process moves to step n-9, in which the electric motor 70 is operated at a predetermined low speed by the low-speed operation signal. (Thus, the toner particle supply means 24 is in a small supply state). On the other hand, in step n-6, the toner concentration value (M ₁ ) detected by the first memory means 60 is substantially equal to the toner concentration value (M ₂ ) detected by the second memory means 62 (M ₁ =M ₂ ) or the above detected toner concentration value (M ₂ )
(M ₁ >M ₂ ), the process moves to step n-10, where the control means 58 does not generate an actuation signal for actuating the electric motor 70, and the process proceeds to step n-11. electric motor 7
0 is inactive (thus, the toner particle supply means 24 is in a supply stopped state). Further, in step n-3 described above, if the detected toner concentration value (M ₁ ) of the first memory means 60 is smaller than the predetermined reference value (M ₃ ) of the third memory means 64 (M ₁ <M ₃ ), If a comparative judgment is made,
Proceeding to step n-12, the detected toner density value (M ₁ ) stored in the first memory means 60 and the detected toner density value (M ₂ ) stored in the second memory means 62 are compared and determined. (Through this comparative judgment, the fluctuation state of the toner density value detected by the toner density detection means is calculated). In step n-12, it is determined that the toner concentration value (M ₁ ) detected by the first memory means 60 is smaller than the toner concentration value (M ₂ ) detected by the second memory means 62 (M ₁ <M ₂ ). If so, the process moves to step n-13, where "high speed" data among the data stored in the fourth memory means 66 is read out. When the "high speed" data is read out, the process moves to step n-14, where the control means 58 reads out the "high speed" data.
A high-speed actuation signal is generated based on the data, and the process then moves to step n-15, where the electric motor 70 is caused to rotate at a predetermined high speed (thus, the toner particle supply means 24 is brought into a high-volume supply state). Become). In step n-12, the toner concentration value (M ₁ ) detected by the first memory means 60 is compared with the toner concentration value (M ₂ ) detected by the second memory means 62 (M ₁ =M ₂ ). If so, the process moves to step n-16, where "medium speed" data among the data stored in the fourth memory means 66 is read out. When the "medium speed" data is read out, the process moves to step n-17, where the control means 58 generates a medium speed operation signal based on the "medium speed" data.
Next, the process moves to step n-18, in which the electric motor 70 is caused to rotate at a predetermined medium speed by the medium speed operation signal (thus, the toner particle supply means 24
is an intermediate supply state). Also, the above step n
-12, when it is determined by comparison that the toner concentration value (M ₁ ) detected by the first memory means 60 is larger than the toner concentration value (M ₂ ) detected by the second memory means 62 (M ₁ >M ₂ ). In this case, step n-
7, the "slow" data is read as described above. When the "low speed" data is read, as described above, the control means 58 generates a low speed operation signal, and the electric motor 70 is caused to rotate at a predetermined low speed (thus, the toner particle supply means 24 enters a small quantity supply state). ). After the electric motor 70 is deactivated in step n-5 and step n-11 as described above, the electric motor 70 is deactivated in step n-9.
After the electric motor 70 enters a low speed rotation state, and after the electric motor 70 enters a medium speed rotation state in step n-18,
Alternatively, after the electric motor 70 enters the high speed rotation state in step n-15, the next step is step n-19.
Moving on, the detected toner density value (M ₁ ) of the first memory means 60 is stored in the second memory means 62.
At this time, the previously stored detected toner density value (M ₂ ) is erased from the second memory means 62, and the detected toner density value (M ₁ ) from the first memory means 60 is newly stored. be done. When the detected toner concentration value (M ₁ ) of the first memory means 60 is stored in the second memory means 62, it is restored and the control as described above is performed at predetermined intervals (intervals of 0.5 to 1 second). It is carried out repeatedly with . Although preferred embodiments of the electrostatic latent image developing device constructed according to the present invention have been described above, various modifications and modifications can be made without departing from the scope of the present invention. For example, in the illustrated example, the rotational speed of the roller constituting the toner particle supply means is switched in three stages, and the toner particle supply state is set in three stages: a large amount supply state, an intermediate supply state, and a small amount supply state. However, if desired, instead of this, it is also possible to set the toner particle supply state in one stage, two stages, or four stages or more. When the toner particle supply state is set to one level, the operation of the electric motor for rotating the toner particle supply means may be controlled as shown in the table.

[Table] To explain in more detail with reference to the above table, when the toner concentration value (M ₁ ) detected by the toner concentration detection means is larger than the predetermined reference value (M ₃ ) of toner concentration (M ₁ >M ₃ ), and the toner concentration value (M ₁ ) detected by the toner concentration detection means is substantially equal to the predetermined reference value (M ₃ ) (M ₁ =M ₃ ) and the toner concentration value detected by the toner concentration detection means before a predetermined period of time. (M ₂ ) (M ₁ >M ₂ ) or substantially equal to the above detected toner concentration value (M ₂ ) (M ₁ =M ₂ )
Sometimes, no actuation signal is generated by the control means;
The electric motor 70 becomes inactive (therefore, the toner particle supply means stops supplying), and the toner concentration value (M ₁ ) detected by the toner concentration detection means is substantially equal to the predetermined reference value (M ₃ ) ( M ₁ = M ₃ ) and smaller than the toner concentration value (M ₂ ) detected by the toner concentration detection means before a predetermined period (M ₁ <M ₂ ),
And when the toner concentration value (M ₁ ) detected by the toner concentration detection means is smaller than the predetermined reference value (M ₃ ) (M ₁ <M ₃ ), the control means generates an activation signal and operates the electric motor 70. (Therefore, the toner particle supply means is in the supply state). Further, when the toner particle supply means is set to two stages (a small amount supply state and a large amount supply state), the operation of the electric motor may be controlled as shown in the table.

[Table] To explain in more detail with reference to the above table, when the toner concentration value (M ₁ ) detected by the toner concentration detection means is larger than the predetermined reference value (M ₃ ) of toner concentration (M ₁ >M ₃ ), and the toner concentration value (M ₁ ) detected by the toner concentration detection means is the predetermined reference value (M ₃ ).
substantially equal to (M ₁ =M ₃ ) and greater than the toner concentration value (M ₂ ) detected by the toner concentration detection means a predetermined period ago (M ₁ >M ₂ ), or the above-mentioned detected toner concentration value (M ₂ ). When they are substantially equal (M ₁ = M ₂ ),
No activation signal is generated by the control means, the electric motor is inactive (therefore, the toner particle supply means is in a supply stop state), and the toner concentration value (M ₁ ) detected by the toner concentration detection means is equal to the predetermined standard. Value ( _M3 )
(M ₁ =M ₃ ) and smaller than the toner concentration value (M ₂ ) detected by the toner concentration detection means a predetermined period ago (M ₁ <M ₂ ), and the toner concentration detected by the toner concentration detection means The value (M ₁ ) is smaller than the predetermined reference value (M ₃ ) (M ₁ <M ₃ ) and larger than the toner concentration value (M ₂ ) detected by the toner density detection means before the predetermined period (M ₁ >M ₂ ). Sometimes, the control means generates a low speed actuation signal to cause the electric motor to rotate at a low speed (thus, the toner particle supply means is rotated at a relatively low speed to provide a small amount) and the toner concentration detection means detects the toner concentration. Toner density value (M ₁ )
is smaller than the above predetermined reference value (M ₃ ) (M ₁ <M ₃ )
and substantially equal to the toner concentration value (M ₂ ) detected by the toner concentration detection means before a predetermined period (M ₁ =M ₂ ) or smaller than the above-mentioned detected toner concentration value (M ₂ ) (M ₁
<M ₂ ), the control means generates a high-speed operation signal and controls the electric motor to rotate at a high speed (therefore, the toner particle supply means is rotated at a relatively high speed and is in a large quantity supply state). do it. Further, in the illustrated example, the toner particle supply means is constituted by a roller, and by changing the rotational speed of this roller, the toner particle supply state can be set in three stages (large amount supply state, intermediate supply state, small amount supply state). However, instead of this, it is also possible to configure as described below. That is, the inside of the toner particle container is divided into a small amount supply section, a large amount supply section, and an intermediate supply section. A plurality of holes having a relatively large diameter are provided, and a plurality of holes larger than the relatively small diameter and smaller than the relatively large diameter are provided in the bottom wall of the intermediate supply section, and the toner particle supply means is connected to the hole of the small amount supply section. It is also possible to include a first shutter member that opens and closes, a second shutter member that opens and closes the hole in the bulk supply section, and a third shutter member that opens and closes the hole in the intermediate supply section. In such a case, when the first shutter member is opened to open the hole in the small amount supply section, a relatively small amount of toner particles will be supplied through the hole (therefore, a small amount supply state will be established), and the second shutter member will be supplied with a relatively small amount of toner particles. When the member is opened to open the hole in the bulk supply section, a relatively large amount of toner particles is supplied through the hole (a large supply state), and when the third shutter member is opened to open the hole in the intermediate supply section. When opened, more than a relatively small amount and less than a relatively large amount of toner particles are dispensed (thus an intermediate supply condition). Further, in the specific example, a device that detects the toner concentration by detecting the conductivity of the developer is used as the toner concentration detection means, but instead of this, the light transmittance of the developer, which is known per se, or It is also possible to use a device that detects the toner concentration by detecting magnetic permeability, or a device that detects the toner concentration by directly or indirectly measuring the volume of the developer (eg, flow rate). As described above, according to the present invention, the control means compares the toner concentration value detected by the toner concentration detection means with a predetermined reference value and calculates the comparison relationship between the two, and
Calculating the fluctuation state of the toner concentration value detected by the toner concentration detection means, and inactivating the toner particle supply means if the detected toner concentration value is larger than a predetermined reference value;
If the detected toner concentration value is smaller than a predetermined reference value, the toner particle supply means is activated, and even if the detected toner concentration value is substantially equal to the predetermined reference value, if the fluctuation state of the detected toner concentration value is in a decreasing trend, the toner particle supply means is activated. Since the operation of the supply means is controlled, the fluctuation state of the detected toner concentration value tends to decrease not only when the detected toner concentration value is smaller than the predetermined reference value, but also when the detected toner concentration value is substantially equal to the predetermined reference value. In this case, since the toner particle supply means is operated to supply toner particles, the range of variation in toner concentration can be maintained within a predetermined small range.

[Brief explanation of drawings]

FIG. 1 is a simplified sectional view showing a portion of an electrostatic latent image developing device and a rotating drum constructed according to the present invention. FIG. 2 is a flowchart showing the control of the control means in the developing device of FIG. 1. 2... Electrostatic latent image developing device, 10... Developer, 1
2...Developer container, 20...Developer application mechanism, 22
... Ear length setting member, 24 ... Toner particle supply means, 26 ... Toner particle container, 34 ... Rotating sleeve member, 56 ... Voltage source, 58 ... Control means, 70 ... Electric motor.

Claims (1)

[Scope of Claims] 1. A developer container containing a developer consisting of carrier particles and toner particles, and a part of the developer in the developer container is retained on the surface and applied to an electrostatic latent image to be developed. a developer applying mechanism; a toner particle container containing toner particles; a toner particle supply means selectively actuated to supply toner particles from the toner particle container into the developer container; An electrostatic device comprising: a toner concentration detection means for detecting the toner concentration in the developer; and a control means for controlling the operation of the toner particle supply means based on the toner concentration value detected by the toner concentration detection means. In the latent image developing device; the control means compares the toner concentration value detected by the toner concentration detection means with a predetermined reference value to calculate a comparison relationship between the two, and also controls fluctuations in the toner concentration value detected by the toner concentration detection means. The state is calculated, and if the detected toner concentration value is larger than a predetermined reference value, the toner particle supply means is deactivated, and if the detected toner concentration value is smaller than the predetermined reference value, the toner particle supply means is activated and the detection is performed. An electrostatic latent image developing device characterized in that, even when the toner concentration value is substantially equal to a predetermined reference value, the operation of the toner particle supply means is controlled if the fluctuation state of the detected toner concentration value tends to decrease. 2. The toner particle supply means has at least two types of operation: a large supply state in which a relatively large amount of toner particles are supplied into the developer container, and a small supply state in which a relatively small amount of toner particles are supplied into the developer container. 2. The electrostatic latent image developing device according to claim 1, wherein the electrostatic latent image developing device is configured to be capable of being brought into a state in which the electrostatic latent image developing device can be brought into the state of the electrostatic latent image developing device. 3. The control means compares the toner concentration value detected by the toner concentration detection means with the toner concentration value detected by the toner concentration detection means a predetermined period before, and calculates a comparison relationship between the two, thereby detecting the fluctuation state. calculate,
An electrostatic latent image developing device according to claim 1 or 2. 4. In addition to the large quantity supply state and the small quantity supply state, the toner particle supply means supplies toner in an amount that is less than the toner particle supply amount in the large quantity supply state and greater than the toner particle supply quantity in the small quantity supply state. The control means is configured to be capable of causing an intermediate supply state in which particles are supplied into the developer container, and the control means is configured such that when the toner concentration value detected by the toner concentration detection means is larger than the predetermined reference value; When the toner concentration value detected by the toner concentration detection means is substantially equal to the predetermined reference value and is larger than or substantially equal to the toner concentration value detected by the toner concentration detection means before the predetermined period, the toner particle supply means when the toner concentration value detected by the toner concentration detection means is substantially equal to the predetermined reference value and smaller than the toner concentration value detected by the toner concentration detection means before the predetermined period; When the toner concentration value detected by the concentration detection means is smaller than the predetermined reference value and larger than the toner concentration value detected by the toner concentration detection means before the predetermined period, causing the toner particle supply means to enter the small amount supply state; When the toner concentration value detected by the toner concentration detection means is smaller than the predetermined reference value and substantially equal to the toner concentration detected by the toner concentration detection means before the predetermined period, the toner particle supply means is placed in the intermediate supply state. and when the toner concentration value detected by the toner concentration detection means is smaller than the predetermined reference value and smaller than the toner concentration detected by the toner concentration detection means before the predetermined period, the toner particle supply means supplies the large amount of toner particles. The electrostatic latent image developing device according to claim 3, wherein the electrostatic latent image developing device is configured to cause the electrostatic latent image to develop. 5. The toner particle supply means is composed of a roller rotatably attached to a discharge opening formed in the toner container, and in the large quantity supply state, the roller is rotated at a relatively high speed and the toner particles are 5. The electrostatic latent image developing device according to claim 4, wherein the roller is rotated at a relatively low speed in the small amount supply state, and the roller is rotated at an intermediate speed in the intermediate supply state. 6. The toner concentration detection means according to any one of claims 1 to 5, wherein the toner concentration detection means detects the toner concentration by detecting the electrical conductivity of the developer in the developer container. Electrostatic latent image developing device.