JPH08202138A - Image forming device - Google Patents

Abstract

PURPOSE: To provide a compact, simple and reliable image forming device capable of processing a value such as the average value of detection levels and an amplitude value, for controlling a toner concentration and deciding the exchange period of a developer by magnetically detecting the periodically vibrated developer, with few additions to a conventional detecting part and reduction in an additional cost. CONSTITUTION: The image forming device using a two-component developer consisting of toner and carriers is provided with a magnetic detecting means 1 magnetically detecting the state of the developer, a vibration imparting means 2 periodically vibrating the developer whose state is detected by the magnetic detecting means and a processing means 3 executing previously set processing based on the output value of the magnetic detecting means detecting the state of the developer periodically vibrated by the vibration imparting means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a printer, an electrophotographic copying machine and a fax machine, and more particularly to an image forming apparatus using a two-component phenomenon agent.

[0002]

2. Description of the Related Art As a conventional method for detecting toner concentration in an image forming apparatus using a two-component phenomenon agent consisting of toner and carrier, since the change in toner concentration causes a change in bulk density, a phenomenon agent is used. Method of magnetically detecting the change in the magnetic permeability of the toner, or the change in the toner concentration causes a change in the fluidity of the phenomenon agent, or electromagnetically, or
A method of optically detecting a change in fluidity is generally used. In the former method, when the toner concentration becomes high as shown in FIG. 6A, a large amount of the toner having the opposite polarity is attached around the carrier, so that the bulk density is small. Become. On the other hand, as shown in FIG. 6 (B), when the toner density is reduced, the number of toner particles attached around the carrier is reduced and the bulk density is increased. That is, in the former method, the relationship between the output value of the magnetic detection unit and the toner concentration is tested by the magnetic detection unit that detects this change in bulk density as a change in magnetic permeability, as shown in FIG. 7A. If the output value of the detection means is V1, the point b on the curve is obtained as the toner concentration, and it is immediately understood that the toner concentration is D1 which is lower than the reference value D0. Therefore, the toner is replenished so as to return to the reference point a on the curve, the bulk density is reduced, and the output value is controlled to V0.

In the latter method, for example, a hopper 11 having a funnel shape as shown in FIG. 8A is arranged in a magnetic brush developing device (not shown), and a phenomenon occurs in the hopper 11. Contains a fixed amount of agent 13, hopper 11
The phenomenon agent 13 is configured to drop from the outlet 12 at the bottom of the. Further, there is a coil 14 and a detection circuit 15 for detecting the fall from the outflow port 12, and the time until the outflow of all the phenomenon agent is detected. The flowability depends on the viscosity of the phenomenon agent. If the toner concentration is low, the phenomenon agent easily flows from the outflow port 12 to improve the fluidity, and if the toner concentration is high, it is difficult to flow and the fluidity deteriorates. Therefore, although it is possible to know the change in the toner concentration from the change in the fluidity of the phenomenon agent (see JP-A-60-216367), there is a drawback that it is difficult to downsize the apparatus. However, when the phenomenon agent deteriorates and the charging ability of the carrier drops, or when finer powdered toner than normal adheres to the carrier and normal toner cannot be adhered, toner is released from the carrier surface. As a result, the carrier scatters from the developing device, causing a background stain on the screen.

When fine powdery toner adheres to the carrier surface as shown in FIG. 6C, the bulk density of the phenomenon agent increases, and the magnetic detection means detects that the toner concentration is apparently low. To be done. However, since the toner concentration is not actually low, if toner is continuously replenished according to the detection result, the amount of toner becomes excessive and toner scattering occurs, resulting in a vicious circle.

FIG. 7B is a relationship diagram between the bulk density and the toner concentration. The solid line shows the relationship curve between the new phenomenon agent and the dotted line shows the deterioration phenomenon agent. Further, FIG. 8B is a relationship diagram between the flowability and the toner concentration, the solid line shows the relationship curve of the new phenomenon agent, and the dotted line shows the relationship curve of the deteriorated phenomenon agent. In this case, too, it can be seen that the deterioration of the phenomenon agent is greatly related to the fluidity. That is, the fluidity decreases as the amount of the deteriorated developer increases.

As a method of detecting the deterioration of the phenomenon agent, although not shown, toner is attached to a part of the photosensitive member (non-image forming part) which does not affect the transfer part every time an image is formed, and the part is adhered to the part. By reading the optical reflected light from the adhered toner, it is known that the deterioration of the phenomenon agent is known and the replacement time of the phenomenon agent is detected. However, this detection method has a problem in that the addition of means for detecting the deterioration of the phenomenon agent is complicated and the cost is high.

[0007]

A conventional method for detecting toner concentration is a method for magnetically detecting a change in magnetic permeability of a phenomenon agent because a change in toner concentration causes a change in bulk density. Alternatively, a method of electromagnetically or optically detecting a change in fluidity has been generally used because a change in toner concentration affects the fluidity of a phenomenon agent. However, in the above two methods, deterioration of the phenomenon agent has a great influence on the detection level, and it is not possible to determine whether the change in the detection level is a change in toner concentration or a change due to deterioration of the phenomenon agent. If the life of the phenomenon agent or the deterioration of the phenomenon agent is determined and then the detection level is corrected, the control becomes complicated and the cost becomes high.

[0008]

SUMMARY OF THE INVENTION Therefore, the present invention controls the toner concentration by magnetically detecting a phenomenon agent to which periodic vibration is applied to process the average value and amplitude value of the detection level. Image forming apparatus, which can be used for a long time, and can determine the replacement timing of the phenomenon agent, and which is small, simple, reliable, and inexpensive to add, with almost no addition to the conventional detection unit. Is intended to provide.

[0009]

In order to achieve the above-mentioned object, the present invention is an image forming apparatus using a two-component phenomenon agent composed of a toner and a carrier, and a magnetic element for magnetically detecting the state of the phenomenon agent. Receiving the output value of the detection means, the vibration applying means for giving periodic vibration to the phenomenon agent detected by the magnetic detection means, and the output value of the magnetic detection means for detecting the state of the phenomenon agent given the periodic vibration. The most main feature is that the image forming apparatus includes a processing unit that performs a predetermined process.

In the image forming apparatus described in the item 1, the processing means receives a value obtained by detecting the state of the phenomenon agent to which the periodic vibration of the magnetic detection means (1) is applied,
The main feature is that the processing is performed using the amplitude value and the average value, the amplitude value and the maximum value, or the combined value of the amplitude value and the minimum value. The main feature of the image forming apparatus according to the above items 1 and 2 is that the image forming apparatus is provided with a density control means for controlling the toner density based on the processing result of the processing means.

The image forming apparatus described in paragraphs 1, 2, and 3 above is mainly configured to include a phenomenon agent exchange unit that determines the time to exchange the phenomenon agent based on the processing result of the processing unit. Characterize. The main feature of the image forming apparatus according to the above item 1 is that the vibration applying means is a sheet-like member attached to a phenomenon agent stirring paddle for stirring the phenomenon agent.

[0012]

In the image forming apparatus constructed as described above, it is possible to apply periodic vibration to the phenomenon agent portion whose state is magnetically detected by the magnetic detection means by the vibration applying means,
In addition to the output level corresponding to the bulk density of the phenomenon agent by one magnetic detection means, the output amplitude level according to the difference in fluidity caused by the vibration of the phenomenon agent can be taken out in a superimposed form, so that output can be obtained. The processing means for receiving and processing can two-dimensionally process the output corresponding to the bulk density and the amplitude output corresponding to the difference in fluidity.

The processing means of the image forming apparatus of the above item 1 receives a value obtained by detecting the state of the phenomenon agent to which the periodic vibration has been applied from the magnetic detection means, and the amplitude value and the average value or the amplitude value. Values and maximum values, or combination values of amplitude values and minimum values can be used according to the intended use, so it is due to the change over time or temperature of the phenomenon agent, or due to the change in toner concentration. Therefore, it is possible to separately determine the replacement and the toner density control due to the deterioration of the phenomenon agent.

By the processing means of the image forming apparatus described in the above item 1, item 2 or item 3, the output level corresponding to the bulk density of the phenomenon agent and the output amplitude level value corresponding to the difference in fluidity are two-dimensionally processed. Therefore, the change in toner concentration and the change due to the deterioration of the phenomenon agent can be discriminated, and the density control means can control the toner density without being affected by the deterioration of the phenomenon agent.

The output means corresponding to the bulk density of the phenomenon agent and the output amplitude level value corresponding to the difference in fluidity are two-dimensionally processed by the processing means of the image forming apparatus according to the above items 1, 2, and 3. Therefore, it is possible to distinguish the change in toner concentration and the change due to the deterioration of the phenomenon agent, and it is possible to easily judge whether the phenomenon agent has deteriorated and has reached a predetermined replacement area. Can determine the optimum replacement time of the phenomenon agent.

Since the vibration applying means of the image forming apparatus of each of the above items is a sheet-like member attached to a phenomenon agent stirring paddle for stirring the phenomenon agent, the size of the apparatus does not change and the cost increases. It is possible to provide an image forming apparatus that can be manufactured at low cost because only a simple sheet-shaped member is added, and that the phenomenon agent portion that is magnetically detected is surely subjected to periodic vibration.

[0017]

Next, an embodiment of the present invention will be described with reference to the drawings. The configuration and general operation of the electrophotographic image forming apparatus are well known, and therefore the description thereof will be omitted, and the description will focus on the aspects of the present invention. FIG. 1 is a block diagram showing a main configuration of an electrophotographic image forming apparatus to which the present invention is applied. In a developing device 7 of the image forming apparatus, an appropriate amount of a two-component phenomenon agent composed of toner and carrier is packed. There is. In the phenomenon agent stirring paddle 6, a rotating body similar to a water wheel having a webbing rod on the outer periphery as shown in the figure rotates at high speed to stir the phenomenon agent in the developing device 7 and attach it around the developing roller 8. On the other hand, an electrostatic latent image corresponding to the image to be formed is formed on the photosensitive drum 9, and when the developing roller 8 is approached, the toner on the developing roller 8 is transferred to the electrostatic latent image on the photosensitive drum 9. The electrostatic latent image is visualized. The desired image is formed by transferring and fixing the visible image on the photoconductor drum 9 to a transfer sheet (not shown). At that time, the amount of toner in the developing device 7 decreases and the amount of toner adhering to the carrier becomes insufficient, or the phenomenon agent deteriorates and the charging ability of the carrier decreases, or the carrier has a finer powder than usual. If the amount of toner adhered around the developing roller 8 is insufficient due to the adherence of the toner and the normal toner cannot be adhered, the image formed is not normal. Therefore, it becomes necessary to control the toner concentration in the developing device 7 to be constant or to replace the developer by detecting deterioration of the phenomenon developer. The present invention provides an image forming apparatus capable of performing the above points easily and accurately.

In other words, the toner concentration of the phenomenon agent contained in the developing device 7 can be detected by the magnetic detection means 1 as a change in bulk density (see FIG. 6) as a change in magnetic permeability. In the present invention, a characteristic is that the developer is subjected to periodic vibration at that time. That is, the vibration applying means 2 is set so as to apply periodic vibration to the phenomenon agent to be detected, and various methods can be considered, but the simplest and surest method will be described here. That is, the vibration applying means 2 is attached to a part or all of the webbing rod of the phenomenon agent stirring paddle 6 in a form protruding from the webbing rod. As the member of the vibration applying means 2, a sheet-like member such as mylar is suitable because it is surely and easily attached.

FIG. 2 shows an enlarged view of the magnetic detection means 1, the vibration applying means 2, and the phenomenon agent stirring paddle 6. In the longitudinal direction of the phenomenon agent stirring paddle 6 (the direction orthogonal to the paper surface = axial direction), the sheet-shaped member 2 is arranged over the range detected by the magnetic detection means 1, and the tip of the sheet-shaped member 2 has the magnetic detection means 1. And are mounted at a distance d very close to. The sheet-shaped member 2 reliably gives periodic vibration to the phenomenon agent to be detected as the phenomenon agent stirring paddle 6 rotates. Therefore, in addition to the output level corresponding to the bulk density of the phenomenon agent, the magnetic detection means 1 takes out the vibration amplitude level to which the vibration is periodically applied by the vibration applying means 2 in a superimposed form (see FIG. 3). .

In this embodiment, the value of the distance d is 1.0 m.
The m-th position is appropriate, and if this interval is too large, the amplitude of vibration becomes small, and if the amplitude is too small, the phenomenon agent located in the detection range of the magnetic detection means 1 is scraped off, and the detection means provided separately. For example, a toner empty error or the like may be detected, or it may take a long time to stabilize the vibration, and a correct average value may not be obtained.

The feature of the present invention lies in the fact that the magnitude of the vibration amplitude level reflects the fluidity of the phenomenon agent. That is, when the phenomenon agent deteriorates and the fluidity deteriorates, the amplitude level of the periodic vibration detected by the magnetic detection means 1 increases (FIG. 3 (B)). The processing means 3 obtains an amplitude value and an average value, or an amplitude value and a maximum value, or an amplitude value and a minimum value from the superimposition level detected by the magnetic detection means 1, and processes the combination value according to the intended use. The processing result is transmitted as an electric signal to the concentration control means 4 and the phenomenon agent exchange notification means 5.

If the toner concentration of the phenomenon agent is low from the processing result of the processing means 3, the density control means 4 supplies the toner to the developing device 7 through the toner supply pipe 4a and controls so that the toner density becomes constant. When the phenomenon agent deteriorates and enters the range of the phenomenon agent exchange area, the phenomenon agent exchange notification means 5 lights the phenomenon agent exchange instruction lamp 5a, or informs the phenomenon agent exchange time by an alarm instruction (not shown) or the like. , Encourage replacement.

3 (A) and 3 (B) are the same as FIG. 1 described above.
The output waveform detected by the magnetic detection means 1 of the image forming apparatus having the above configuration is shown. In FIG. 3A, the toner concentration is 6 wt. Fig. 3 shows the output waveform of the new phenomenon agent in%.
(B) has a toner concentration of 6 wt. % Is the output waveform with the deteriorated phenomenon agent. The period ts in which the amplitude is generated is naturally the same because it is synchronized with the rotation period of the phenomenon agent stirring paddle 6, but it is clear that there is a significant difference in the amplitude value (Vmax-Vmin). The average value of the output waveform is Vav
If n, the amplitude value and the average value Vavn, or the amplitude value and the maximum value Vmax, and the amplitude value and the minimum value Vmin are detected by one magnetic detection means 1, and the change of the bulk density and the change of the fluidity can be easily performed. There is a feature in understanding.

FIG. 4 shows changes in bulk density and outflow time (which are related to good and bad fluidity as shown in the figure) on the abscissa and ordinate, respectively, with toner concentration and deterioration of the developing agent as parameters. It is the obtained two-dimensional coordinates. However, the outflow time is represented by the time until the flow of a certain amount of the phenomenon agent as shown in FIG. 8 is finished, and the temperature of the phenomenon agent is constant. In addition, the degree of deterioration of the phenomenon agent is compared in three states, that is, when the phenomenon agent is new, when it starts to deteriorate slightly, and when it reaches the end of its life.

When the toner is 5 wt. %
If the point c, which corresponds to
wt. When it falls to%, it moves from the reference point c to the point f, the bulk density increases and the fluidity improves (FIG. 7 (B) and FIG. 8).
(B)). On the contrary, when the toner density becomes high, the toner moves to the upper left direction, the bulk density decreases, and the fluidity deteriorates (the time required for outflow completion becomes long). Further, the toner concentration of the phenomenon agent is 5 wt. When the phenomenon agent is deteriorated and the charging ability is reduced while the percentage remains at%, the point moves to the upper right direction from point c to point e to point g, the bulk density increases and the fluidity deteriorates.

Conventionally, the toner density is judged based on either the bulk density or the fluidity. Therefore, even if the phenomenon agent is deteriorated as in this case, the bulk density and the fluidity are changed. It was not possible to discriminate the difference between the two states (difference in bulk density) (difference in fluidity). That is, if the bulk density is controlled to be constant for a long time, as the phenomenon agent deteriorates, it moves in the direction of c point → m point → n point.
Obviously, it does not control the toner density.
Here, we dealt with the case where the phenomenon agent temperature is constant,
Since the influence of the temperature rise remarkably promotes the deterioration of the phenomenon agent, it is possible to treat the temperature increase as a factor for determining the deterioration of the phenomenon agent in actual control.

FIG. 5 is a two-dimensional coordinate obtained on the basis of the above-mentioned idea. The horizontal axis is the average voltage Vavn detected by the magnetic detection means 1 and the amplitude voltage (Vmax-Vmin).
Is a two-dimensional coordinate represented by the vertical axis. The curve using the degree of deterioration of the phenomenon agent as a parameter also includes the effect of temperature rise. As a method of controlling the toner concentration of the phenomenon agent by the processing means 3, when the deterioration of the phenomenon agent progresses, the reference point is o point (coordinates V0, P0) → p point (coordinate V).
It is understood that the coordinate control may be performed from 1.P1) to q point (coordinates V2, P2). The coordinates above the point q, that is, the shaded area above the curve of the deterioration of the phenomenon agent is the phenomenon agent life area, and indicates the range where the phenomenon agent needs to be replaced as soon as possible. There is.

Since the density control in the image forming apparatus of the present invention is performed on the basis of the above-mentioned criteria, deterioration of the phenomenon agent does not significantly affect the detection level, and whether the change of the detection level is a change of the toner density, It is possible to properly distinguish whether the change is due to deterioration of the phenomenon agent. Further, since the detection level is not corrected after determining the life of the phenomenon agent or the deterioration of the phenomenon agent, there is no problem that the control becomes complicated and the cost becomes expensive.

[0029]

As described above, according to the present invention, when the state of a phenomenon agent is magnetically detected by the magnetic detection means, the vibration agent means periodically vibrates the phenomenon agent portion to be detected. Since it is given, by one magnetic detection means, in addition to the output level corresponding to the bulk density of the phenomenon agent, the output amplitude level according to the difference in fluidity due to the vibration of the phenomenon agent can be taken out in a superimposed form. Since the processing means that receives the output and processes the output corresponding to the bulk density and the amplitude output according to the difference in fluidity can be processed two-dimensionally, only one output is used for the determination. In addition to the conventional processing method, it is possible to perform various kinds of condition changes and perform processing that is suitable for actual use with high accuracy.

The processing means of the image forming apparatus according to the first aspect receives the value obtained by detecting the state of the phenomenon agent to which the periodic vibration is applied from the magnetic detection means, and the amplitude value and the average value or the amplitude value. Values and maximum values, or combination values of amplitude values and minimum values can be used according to the intended use, due to changes over time and temperature changes of the phenomenon agent, and due to changes in toner concentration. Therefore, it is possible to determine the optimum replacement time of the phenomenon agent, and it is possible to maintain a uniform toner concentration for any time.

The processing means of the image forming apparatus of the above-described items 1 and 2 can two-dimensionally process the output level corresponding to the bulk density of the phenomenon agent and the output amplitude level corresponding to the difference in fluidity. As a result, the change in toner concentration and the change due to the deterioration of the phenomenon agent can be discriminated, so that the density control unit can accurately control the toner concentration without being affected by the deterioration of the phenomenon agent.

The processing means of the image forming apparatus of the above-mentioned items 1, 2 and 3 two-dimensionally processes the output level corresponding to the bulk density of the phenomenon agent and the output amplitude level corresponding to the difference in fluidity. The change in the toner concentration and the change due to the deterioration of the phenomenon agent can be discriminated, so it is possible to easily judge whether the phenomenon agent has deteriorated and has reached a predetermined replacement area.
Since it becomes possible to determine the optimum replacement time by the instruction of the phenomenon agent replacement notification means, there is no waste of replacing the phenomenon agent which is still sufficiently usable and which has little deterioration by mistake as deterioration, and the toner concentration during image formation is I was able to save the trouble of re-copying after I noticed it was thin.

Since the vibration applying means of the image forming apparatus of each of the above items is a sheet-like member attached to the phenomenon agent stirring paddle for stirring the phenomenon agent, the size of the apparatus can be changed without adding parts. There is no cost increase, it is simpler than the conventional methods of measuring the fluidity of a phenomenon agent, it is very cheap, and the state of the phenomenon agent is magnetically detected. An image forming apparatus can now be provided.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a main part of an image forming apparatus according to an exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part around a phenomenon agent stirring paddle and a magnetic detection means showing an embodiment of the present invention.

FIG. 3A is an explanatory diagram of an output waveform in which a magnetic agent of an image forming apparatus according to an exemplary embodiment of the present invention detects a phenomenon agent when new, and FIG. 3B illustrates an image forming according to an exemplary embodiment of the present invention. It is explanatory drawing of the output waveform which detected the phenomenon agent deteriorated by the magnetic detection means of an apparatus.

FIG. 4 is an explanatory diagram of a two-dimensional coordinate of the bulk density of the developing agent and the outflow time with the toner concentration and the deterioration of the developing agent as parameters.

FIG. 5 is an explanatory diagram of the two-dimensional coordinates of the detected average voltage and the amplitude voltage of the magnetic detection unit using the toner concentration and the deterioration of the phenomenon agent as parameters.

6A is an explanatory diagram showing a state of a two-component phenomenon agent having a large toner concentration and a small bulk density, and FIG. 6B is an explanatory diagram showing a state of a two-component phenomenon agent having a small toner concentration and a large bulk density; (C) is an explanatory view showing a state of a two-component phenomenon agent having a large toner density and a large bulk density.

7A is an explanatory diagram illustrating a relationship between a detection voltage of a magnetic detection unit and a toner concentration, and FIG. 7B is an explanatory diagram illustrating a relationship between a bulk density of a phenomenon agent and a toner concentration. .

FIG. 8A is an explanatory diagram of a main part of a conventional example for detecting the outflow time of the phenomenon agent, and FIG. 8B is an explanatory diagram illustrating a relationship between the outflow time of the phenomenon agent and the toner concentration.

[Explanation of symbols]

1 ... Magnetic detecting means, 2 ... Vibration applying means, 3 ...
-Processing means, 4 ... Density control means, 4a ... Toner supply pipe 4a, 5 ... Phenomenon agent exchange notification means, 5a
..Phenomenon agent replacement instruction lamp, 6 ... Phenomenon agent stirring paddle, 7 ... Developing device, 8 ... Developing roller, 9 ...
Photoconductor drum.

Claims (5)

[Claims] 1. An image forming apparatus using a two-component phenomenon agent comprising toner and carrier, comprising: a magnetic detection means for magnetically detecting the state of the phenomenon agent; and a phenomenon agent for detecting the state by the magnetic detection means. Vibration applying means for applying periodic vibration, and processing means for performing a predetermined process based on the output value of the magnetic detection means for detecting the state of the phenomenon agent to which the periodic vibration is applied by the vibration applying means. An image forming apparatus comprising: 2. The image forming apparatus according to claim 1,
The processing means, based on the output value from the magnetic detection means that has detected the state of the phenomenon agent to which the periodic vibration is given, an amplitude value and an average value, or an amplitude value and a maximum value, or an amplitude value and The image forming apparatus according to claim 1, wherein the processing is performed using a combination value of the minimum values. 3. The image forming apparatus according to claim 1, further comprising density control means for controlling the toner density based on the processing result of the processing means. 4. The image forming method according to claim 1, further comprising: a phenomenon agent exchange unit that determines a time to exchange the phenomenon agent based on a processing result of the processing unit. apparatus. 5. The vibration-applying means is a sheet-shaped member attached to a phenomenon-agent stirring paddle for stirring the phenomenon agent.
Alternatively, the image forming apparatus according to claim 4.