JP2021033022A - Toner storage device and image forming apparatus - Google Patents

Abstract

To prevent erroneous detection of the amount of toner in a toner storage device that adopts a configuration where an internal bottom face of a toner storage unit is bent in substantially an arc shape when viewed from an axial direction of rotary members.SOLUTION: A toner storage device comprises toner amount detection means 9d, 9e, 9f that detect the amount of toner in a toner storage unit 9, and comprises rotary members 9b, 9c in the toner storage unit. An internal bottom face of the toner storage unit is bent in substantially an arc shape when viewed from an axial direction of the rotary members. The toner amount detection means detect the amount of toner in the toner storage unit on the basis of the capacitance between an upper electrode part 9d and a lower electrode part 9e that are arranged vertically sandwiching the toner in the toner storage unit. The lower electrode part is arranged over the entire width in the horizontal direction of the internal bottom face when viewed from the axial direction of the rotary members.SELECTED DRAWING: Figure 5

Description

The present invention relates to a toner accommodating device and an image forming device.

Conventionally, a toner accommodating device including a toner amount detecting means for detecting the amount of toner in the toner accommodating portion has been known.

For example, in Patent Document 1, a toner transfer belt stretched on two rollers arranged horizontally with each other is arranged in a developing device container (toner accommodating portion) arranged on the side of a developing sleeve. The developing device is disclosed. This developing device circulates and moves the toner transport belt to transport the toner in the developing device container to the developing sleeve side along the horizontal direction. In this developing device, electrode portions are arranged on the inner bottom surface and the inner top surface of the developing apparatus container, respectively, and the capacitance for detecting the amount of toner in the developing apparatus container based on the capacitance between these electrode portions. Adopt a detection method.

Some conventional toner accommodating devices are provided with a rotating member such as an agitator or a transfer screw inside the toner accommodating portion, and the inner bottom surface of the toner accommodating portion has a substantially arc shape when viewed from the axial direction of the rotating member. It is curved. When the capacitance detection method is adopted in the toner accommodating device having such a configuration, there is a problem that erroneous detection of the toner amount is likely to occur.

In order to solve the above-mentioned problems, the present invention is a toner accommodating device provided with a toner amount detecting means for detecting the amount of toner in the toner accommodating portion, wherein a rotating member is provided in the toner accommodating portion and the toner accommodating portion is provided. The inner bottom surface of the above is curved in a substantially arc shape when viewed from the axial direction of the rotating member, and the toner amount detecting means has an upper electrode portion arranged so as to sandwich the toner in the toner accommodating portion up and down. The amount of toner in the toner accommodating portion is detected based on the capacitance between the lower electrode portion and the lower electrode portion, and the lower electrode portion has the entire horizontal width of the inner bottom surface when viewed from the axial direction of the rotating member. It is characterized in that it is arranged over.

According to the present invention, it is possible to suppress erroneous detection of the amount of toner in a toner accommodating device that employs a configuration in which the inner bottom surface of the toner accommodating portion is curved in a substantially arc shape when viewed from the axial direction of the rotating member. ..

The schematic block diagram which shows the image forming apparatus which concerns on embodiment. An enlarged configuration diagram showing an enlarged view of the photoconductor and its surrounding configuration in the image forming apparatus. The explanatory view which shows typically the structure of the toner amount detecting means of the comparative example 1. FIG. The explanatory view which shows typically the structure of the toner amount detecting means of the comparative example 2. FIG. The explanatory view which shows the structure of the toner replenishing apparatus in embodiment. The perspective view which shows typically the structure of the toner amount detecting means in embodiment. The explanatory view which shows the state which the toner in a toner hopper is biased in the toner replenishment apparatus. An explanatory view showing a state in which toner remains at the bottom of the inner bottom surface of the toner hopper in the toner replenishment device. The graph which showed the experimental result which shows the capacitance value measured by the toner amount detecting means of the comparative example 2 and the actual toner amount (toner weight) in a toner hopper. The graph which shows the accelerated cohesion degree of three kinds of toners, F2 toner, CE2 toner, and NF toner used in the experiment. The graph which showed the experimental result which shows the capacitance value measured by the toner amount detecting means of embodiment, and the actual toner amount (toner weight) in a toner hopper. The explanatory view which shows the structure of the toner replenishing apparatus in the modification 1. FIG. The explanatory view which shows the structure of the toner replenishing apparatus in the modification 2. The explanatory view which shows an example of the structure of the toner replenishing apparatus in the modification 3. The explanatory view which shows another example of the structure of the toner replenishing apparatus in the modification 3.

Hereinafter, an electrophotographic image forming apparatus for forming an image by an electrophotographic method to which the present invention is applied will be described.
First, the basic configuration of the image forming apparatus according to the embodiment will be described.
FIG. 1 is a schematic configuration diagram showing an image forming apparatus according to an embodiment.
In the figure, the image forming apparatus includes a photoconductor 1 as a latent image carrier, a paper feed cassette 100 that is detachably attached to and detachable from a main body housing 50, and the like. Inside the paper cassette 100, a plurality of recording media S are housed in a bundle of sheets.

The recording sheet S in the paper feed cassette 100 is fed out of the cassette by the rotational drive of the feed roller 35, passes through the separation nip, and then reaches the feed path 42. After that, it is sandwiched between the transport nips of the pair of feed relay rollers 41, and is transported in the feed path 42 from the upstream side to the downstream side in the transport direction. A pair of resist rollers 49 are arranged near the end of the supply path 42. The recording sheet S is temporarily suspended with its tip abutting against the resist nip of the resist roller 49. At the time of the abutting, the skew of the recording sheet S is corrected.

The resist roller 49 starts rotational driving at a timing when the recording sheet S can be superimposed on the toner image on the surface of the photoconductor 1 at the transfer nip, and sends the recording sheet S toward the transfer nip. At this time, the feed / relay relay roller 41 starts the rotary drive at the same time, and resumes the transport of the recording sheet S, which has been temporarily suspended.

An image reading unit 60 is attached to the upper part of the main body housing 50. Further, an automatic document transfer device 61 is attached to the image reading unit 60. The automatic document transfer device 61 separates the originals one by one from the original bundle placed on the original tray 61a and automatically feeds the originals to the contact glass on the image reading unit 60. The image reading unit 60 reads the document conveyed on the contact glass by the automatic document conveying device 61.

FIG. 2 is an enlarged configuration diagram showing an enlarged view of the photoconductor 1 and its surrounding configuration in the image forming apparatus.
Around the drum-shaped photoconductor 1 driven to rotate counterclockwise in the figure, a recovery screw 3, a cleaning blade 2, a charging roller 4, a latent image writing device 7 as a latent image forming means, and a developing means as a developing means. A device 8, a transfer roller 10 as a transfer means, and the like are arranged. The charging roller 4 provided with the conductive rubber roller portion rotates while in contact with the photoconductor 1 to form a charging nip. A charging bias output from the power supply is applied to the charging roller 4. As a result, in the charging nip, an electric discharge is generated between the surface of the photoconductor 1 and the surface of the charging roller 4, so that the surface of the photoconductor 1 is uniformly charged.

The latent image writing device 7 includes an LED array, and image data input from a personal computer or image data of a document read by an image reading unit 60 on a uniformly charged surface of the photoconductor 1. Light irradiation with LED light based on the above is performed. Of the uniformly charged background portion of the photoconductor 1, the region irradiated with light attenuates the potential. As a result, an electrostatic latent image is formed on the surface of the photoconductor 1.

The electrostatic latent image passes through the developing region facing the developing device 8 as the photoconductor 1 is rotationally driven. The developing apparatus 8 has a circulating transport section and a developing section, and the circulating transport section contains a developer containing toner and a magnetic carrier. The circulation transport unit has a first screw 8b for transporting the developer to be supplied to the developing roller 8a, and a second screw 8c for transporting the developer in an independent space located directly below the first screw 8b. There is. Further, it also has an inclined screw 8d for transferring the developer from the second screw 8c to the first screw 8b. The developing rollers 8a, the first screw 8b, and the second screw 8c are arranged in a posture parallel to each other. On the other hand, the inclined screws 8d are arranged in an inclined posture from them.

The first screw 8b conveys the developer from the back side to the front side in the direction orthogonal to the paper surface in the figure as it is driven to rotate. At this time, a part of the developing agent is supplied to the developing rollers 8a arranged to face each other. The developer conveyed by the first screw 8b to the vicinity of the front end in the direction orthogonal to the paper surface in the figure is dropped onto the second screw 8c.

While receiving the used developer from the developing roller 8a, the second screw 8c conveys the received developer from the back side to the front side in the direction orthogonal to the paper surface in the figure as it drives its own rotation. .. The developer conveyed by the second screw 8c to the vicinity of the front end in the direction orthogonal to the paper surface in the figure is delivered to the inclined screw 8d. Then, as the inclined screw 8d is rotationally driven, it is conveyed from the front side to the back side in the direction orthogonal to the paper surface in the figure, and then becomes the first screw 8b near the end portion on the back side in the same direction. Delivered.

The developing roller 8a includes a rotatable developing sleeve made of a tubular non-magnetic member, and a magnet roller fixed in the sleeve so as not to rotate with the developing sleeve. Then, a part of the developing agent conveyed by the first screw 8b is pumped up on the surface of the developing sleeve by the magnetic force generated by the magnet roller. The layer thickness of the developer carried on the surface of the developing sleeve is regulated as it passes around the surface of the developing sleeve and passes through the opposite positions of the sleeve and the doctor grade. After that, it moves while rubbing against the surface of the photoconductor 1 in the developing region facing the photoconductor 1.

A development bias having the same polarity as the background potential of the toner or the photoconductor 1 is applied to the development sleeve. The absolute value of this development bias is larger than the absolute value of the latent image potential and smaller than the absolute value of the background potential. Therefore, in the developing region, a developing potential that electrostatically moves the toner from the sleeve side to the latent image side acts between the electrostatic latent image of the photoconductor 1 and the developing sleeve. On the other hand, between the background portion of the photoconductor 1 and the developing sleeve, a background potential that electrostatically moves the toner from the background portion side to the sleeve side acts. As a result, in the developing region, toner is selectively adhered to the electrostatic latent image of the photoconductor 1, and the electrostatic latent image is developed.

The developer that has passed through the developing region enters the facing region between the sleeve and the second screw 8c as the developing sleeve rotates. In this facing region, a repulsive magnetic field is formed by two magnetic poles having different polarities from each other among the plurality of magnetic poles provided in the magnet roller. The developer that has entered the opposite region is separated from the surface of the developing sleeve by the action of the repulsive magnetic field and collected on the second screw 8c.

The developer conveyed by the inclined screw 8d contains the developer recovered from the developing roller 8a, and the developer contributes to the development in the developing region, so that the toner concentration is lowered. The developing device 8 includes a toner concentration sensor that detects the toner concentration of the developer conveyed by the tilt screw 8d. Based on the detection result by the toner concentration sensor, a replenishment operation for replenishing the developer conveyed by the tilt screw 8d is executed as necessary.

A toner hopper 9 as a toner accommodating portion is arranged above the developing device 8. The toner hopper 9 agitates the toner contained therein by an agitator 9b as a first rotating member fixed to the rotating shaft 9a. Further, the toner hopper 9 is provided internally with a toner replenishment screw 9c as a second rotating member that conveys toner in the direction of the rotation axis. The rotation shaft 9a of the agitator 9b and the rotation shaft of the toner replenishment screw 9c are positioned substantially parallel to each other and laterally displaced from each other.

As shown in FIG. 2, the inner bottom surface of the toner hopper 9 has a bottom surface portion facing the agitator 9b curved in a substantially arc shape when viewed from the axial direction of the agitator 9b, and faces the toner replenishment screw 9c. The bottom surface is also curved in a substantially arc shape when viewed from the axial direction of the toner replenishment screw 9c. This is because the inner bottom surface of the toner hopper 9 is curved in a substantially arc shape along the outer peripheral trajectory of the agitator 9b and the toner replenishment screw 9c so that the amount of toner that cannot contact the agitator 9b and the toner replenishment screw 9c in the toner hopper 9 is reduced. This is to suppress the toner transfer residue (toner retention).

The agitator 9b is rotationally driven in the counterclockwise direction in FIG. 2 and conveys toner in a direction orthogonal to the rotation axis 9a. Specifically, the toner accumulated on the bottom surface of the toner hopper 9 is conveyed to the toner replenishment screw 9c side (right side in FIG. 2) by the agitator 9b that is rotationally driven. The toner replenishment screw 9c rotates around the rotation axis to convey the toner in the direction of the rotation axis to the toner replenishment path side communicating with the developing device 8. The rotation drive of the toner replenishment screw 9c is controlled according to the replenishment operation signal output from the main body control unit, and an amount of toner corresponding to the rotation drive amount is supplied to the first screw 8b of the developing device 8 via the toner replenishment path. Replenish.

The toner image formed on the photoconductor 1 by the development enters the transfer nip where the photoconductor 1 and the transfer roller 10 serving as the transfer means come into contact with each other as the photoconductor 1 rotates. A charging bias having a polarity opposite to the latent image potential of the photoconductor 1 is applied to the transfer roller 10, whereby a transfer electric field is formed in the transfer nip.

As described above, the resist roller 49 feeds the recording sheet S toward the transfer nip at a timing when it can be superimposed on the toner image on the photoconductor 1 in the transfer nip. The toner image on the photoconductor 1 is transferred to the recording sheet S which is brought into close contact with the toner image by the transfer nip by the action of the transfer electric field and the nip pressure.

The transfer residual toner that has not been transferred to the recording sheet S adheres to the surface of the photoconductor 1 after passing through the transfer nip. The transfer residual toner is scraped off from the surface of the photoconductor 1 by the cleaning blade 2 in contact with the photoconductor 1, and then sent to the outside of the unit casing by the recovery screw 3. The transfer residual toner discharged from the unit casing is sent to the waste toner bottle by the waste toner transfer device.

The surface of the photoconductor 1 cleaned by the cleaning blade 2 is statically removed by the static elimination means, and then uniformly charged again by the charging roller 4. Foreign substances such as toner additives and toner that cannot be completely removed by the cleaning blade 2 adhere to the charging roller 4 that is in contact with the surface of the photoconductor 1. This foreign matter is transferred to the cleaning roller 5 in contact with the charging roller 4, and then scraped off from the surface of the cleaning roller 5 by the scraper 6 in contact with the cleaning roller 5. The scraped foreign matter falls on the recovery screw 3 described above.

In FIG. 1, the recording sheet S that has passed through the transfer nip where the photoconductor 1 and the transfer roller 10 come into contact with each other is sent to the fixing device 44. The fixing device 44 forms a fixing nip by abutting the fixing roller 44a including a heat generating source such as a halogen lamp and the pressure roller 44b pressed toward the fixing roller 44a. A toner image is fixed on the surface of the recording sheet S sandwiched between the fixing nips by the action of heating or pressurizing. After that, the recording sheet S that has passed through the fixing device 44 passes through the paper ejection path 45, is sandwiched between the paper ejection nips of the paper ejection roller 46, and is ejected to the outside of the machine by the paper ejection roller 46. The discharged recording sheet S is stacked on a stack portion 51 provided on the upper surface of the main body housing 50.

Next, the toner remaining amount detection of the toner hopper 9, which is a feature of the present invention, will be described.
In a toner replenishing device (toner accommodating device) provided with a rotating member such as an agitator 9b or a toner replenishing screw 9c in the toner hopper 9, as described above, when the inner bottom surface of the toner hopper 9 is viewed from the axial direction of the rotating member. Adopts a configuration that is curved in a substantially arc shape. In such a configuration, as shown in FIG. 3, the toner on the inner bottom surface is biased to one side in the horizontal direction (hereinafter referred to as “horizontal direction”) when viewed from the axial direction of the rotating member, or is on the inner bottom surface. The toner may undulate in the horizontal direction, and the bulk of the toner in the horizontal direction may change irregularly rather than being constant. Therefore, as in Comparative Example 1 shown in FIG. 3, a toner amount detecting means that can detect only the toner deposited on a part of the inner bottom surface of the toner accommodating portion in the lateral direction can accurately detect the toner amount in the configuration. It is difficult to detect.

That is, the toner amount detecting means of Comparative Example 1 shown in FIG. 3 is based on the capacitance between the upper electrode portion 9d'and the lower electrode portion 9e'arranged so as to sandwich the toner in the toner hopper 9 at the top and bottom. The toner amount in the toner hopper 9 is detected. In this configuration, as shown in FIG. 3, the lower electrode portion 9e'is provided only on a part of the inner bottom surface of the toner hopper 9 in the lateral direction. Therefore, when the toner T in the toner hopper 9 is biased to one side in the lateral direction as shown in FIG. 3, the upper electrode portion 9d'even though the toner T still remains sufficiently in the toner hopper 9. Since there is no toner between the lower electrode portion 9e'and the lower electrode portion 9e', it is erroneously detected that the remaining amount of toner is exhausted.

Further, even in the case of the configuration as shown in Comparative Example 2 shown in FIG. 4, the toner amount detecting means that can detect only the toner deposited on a part of the inner bottom surface of the toner accommodating portion in the lateral direction is the toner in the configuration. It is difficult to accurately detect the amount.

That is, the toner amount detecting means of Comparative Example 2 also has the toner hopper 9 based on the capacitance between the upper electrode portion 9d'and the lower electrode portion 9e'arranged so as to sandwich the toner in the toner hopper 9 at the top and bottom. It detects the amount of toner inside. In this configuration, as shown in FIG. 4, the lower electrode portion 9e'is provided only on a part (lowermost portion) of the inner bottom surface of the toner hopper 9 in the lateral direction. Since the toner T tends to remain at the bottom of the inner bottom surface of the toner hopper 9, as shown in FIG. 4, although the toner T hardly remains in the toner hopper 9, the upper electrode portion 9d'and the lower side Since the toner T exists between the electrode portion 9e'and the electrode portion 9e', it is erroneously detected that the remaining amount of toner is still present.

FIG. 5 is an explanatory diagram showing a configuration of a toner replenishing device (toner accommodating device) in the present embodiment.
In the present embodiment, the toner T on the inner bottom surface of the toner hopper 9 is biased to one side in the lateral direction, or the toner T on the inner bottom surface is wavy in the lateral direction, so that the toner bulk in the lateral direction is not constant. Provided is a configuration capable of suppressing erroneous detection of the amount of toner in the toner hopper 9 even if the configuration can change irregularly. Specifically, as shown in FIG. 5, the inside of the toner hopper 9 is based on the capacitance between the upper electrode portion 9d and the lower electrode portion 9e arranged so as to sandwich the toner T in the toner hopper 9 at the top and bottom. A toner amount detecting means for detecting the amount of toner is used, and the lower electrode portion 9e thereof is arranged along the inner bottom surface of the toner hopper 9 over the entire lateral direction of the inner bottom surface of the toner hopper 9.

As a result, the amount of toner can be detected based on the capacitance of the toner hopper 9 over the entire lateral direction, so that even if the bulk of the toner in the lateral direction changes irregularly, the effect is affected. The amount of toner can be detected without receiving it.

The upper electrode portion 9d and the lower electrode portion 9e are not particularly limited as long as they are conductive members, and in the present embodiment, an iron plate material having a thickness of 1 [mm] is used. As shown in FIG. 5, the upper electrode portion 9d and the lower electrode portion 9e have shielded wires 9h fixed to their respective ends by screws 9g, and are connected to the capacitance detection circuit 9f via the shielded wires 9h. Has been done. Both the upper electrode portion 9d and the lower electrode portion 9e are provided with a portion protruding to the outside of the toner hopper 9, and the shielded wire 9h is screwed to the portion.

In the present embodiment, for the agitator 9b, for example, a configuration in which a member having a length of 12 [mm] is supported by a rotating shaft 9a having a radius of 3 [mm] can be adopted. Further, for the toner replenishment screw 9c, for example, a screw member having a radius (length from the center of rotation to the outer peripheral portion of the screw) of 5 [mm] can be adopted.

As shown in FIG. 5, the upper electrode portion 9d and the lower electrode portion 9e of the present embodiment are attached to the outer surface of the wall portion of the toner hopper 9. By providing the upper electrode portion 9d and the lower electrode portion 9e outside the toner hopper 9 in this way, the agitator 9b and the toner replenishment screw 9c do not come into contact with the upper electrode portion 9d and the lower electrode portion 9e, so that the upper electrode portion 9d In addition, toner aggregation does not occur on the lower electrode portion 9e due to frictional heat or the like. Further, there is an advantage that the assembling property is better than the case where the upper electrode portion 9d and the lower electrode portion 9e are provided inside the toner hopper 9.

FIG. 6 is a perspective view schematically showing the configuration of the toner amount detecting means in the present embodiment.
Since the upper surface of the toner hopper 9 is flat, the upper electrode portion 9d of the present embodiment has a flat plate shape in accordance with this. On the other hand, the lower electrode portion 9e has a curved plate shape so as to follow the inner bottom surface (curved surface) over the entire width (entire lateral direction) of the inner bottom surface of the toner hopper 9. In the present embodiment, for example, the electrode portion 9e1 arranged along the inner bottom surface portion facing the agitator 9b has an arcuate curved plate shape with a radius of curvature of 18 [mm] and faces the toner replenishing screw 9c. The electrode portion 9e2 arranged along the inner bottom surface portion is in the shape of an arc-shaped curved plate having a radius of curvature of 8 [mm].

Next, a method of calculating the remaining amount of toner in the toner hopper 9 in the present embodiment will be described.
In the present embodiment, the capacitance between the upper electrode portion 9d and the lower electrode portion 9e is measured by the capacitance detection circuit 9f. A general method may be used for measuring the capacitance. In this embodiment, a constant voltage / current is applied between the electrodes, and the capacitance is measured from the relationship between the time at the charging arrival point and the voltage / current. Measure by charging method. The capacitance measured here changes depending on the dielectric constant between the upper electrode portion 9d and the lower electrode portion 9e. Then, when the amount of the toner T having a high dielectric constant with respect to air changes, the dielectric constant changes. Therefore, from the measurement result of the capacitance between the upper electrode portion 9d and the lower electrode portion 9e, The amount of toner existing between the upper electrode portion 9d and the lower electrode portion 9e can be detected.

In the present embodiment, since the lower electrode portion 9e is arranged over the entire lateral direction of the toner hopper, the entire toner in the toner hopper 9 is below the upper electrode portion 9d at least when the remaining amount of toner is low to some extent. It will exist between the side electrode portion 9e and the side electrode portion 9e. Therefore, as shown in FIG. 7, even if the toner bulk in the lateral direction is not constant and changes irregularly, the amount of toner existing between the upper electrode portion 9d and the lower electrode portion 9e does not change. Therefore, since the capacitance between the upper electrode portion 9d and the lower electrode portion 9e does not change, the amount of toner in the toner hopper 9 can be accurately detected without erroneous detection.

Further, if the lower electrode portion 9e is arranged over the entire lateral direction of the toner hopper as in the present embodiment, as shown in FIG. 8, the toner T remains at the bottom of the inner bottom surface of the toner hopper 9. Even so, the amount of toner in the toner hopper 9 can be accurately detected without erroneous detection.

FIG. 9 is a graph showing the experimental results showing the capacitance value measured by the toner amount detecting means of Comparative Example 2 shown in FIG. 4 and the actual toner amount (toner weight) in the toner hopper 9. ..
In this experiment, three types of toner, F2 toner, CE2 toner, and NF toner, were used. The degree of accelerated cohesion, which is a characteristic of each powder, is as shown in FIG. The lower the degree of accelerated cohesion, the higher the fluidity, indicating that the toner is smooth.

Further, in this experiment, the toner replenishment screw 9c and the agitator 9b were driven under two conditions, a high duty condition and a low duty condition, respectively. The high duty condition is a condition in which the drive pattern of turning on for 0.2 seconds and then turning off for 0.1 seconds is repeated, and the low duty condition is a driving pattern in which the drive pattern is turned on for 0.2 seconds and then turned off for 19.8 seconds. It is a condition to repeat. In FIG. 9, the result of the high duty condition is shown by a dotted line, and the result of the low duty condition is shown by a solid line.

As shown in FIG. 9, in each of the toner conditions and the driving conditions, the capacitance value is 0.65 [pF] even though the actual toner amount (toner weight) in the toner hopper 9 is 2 [g]. ], And it is erroneously detected that the amount of toner is sufficient. This is because, in Comparative Example 2 shown in FIG. 4, since the toner T locally remained at the lowermost part of the inner bottom surface of the toner hopper 9, the remaining amount of toner was still remaining even though almost no toner T remained in the toner hopper 9. It was falsely detected as having. In this case, since the toner is not replenished from the toner bottle to the toner hopper 9, when a solid image is printed, the toner is insufficient and an image quality problem of faint density occurs.

Further, as shown by an arrow in FIG. 9, even if the measured capacitance value is the same 0.69 [pF], a maximum variation of about 3 [g] may occur due to a difference in driving conditions. confirmed. That is, if the amount of toner in the toner hopper 9 for the same capacitance value changes due to the difference in driving conditions (difference in driving time ratio), accurate toner amount detection cannot be realized, and the toner bottle cannot be used. It causes problems such as oversupply of the toner hopper 9 and the inability to replenish the required amount.

FIG. 11 is a graph showing the experimental results showing the capacitance value measured by the toner amount detecting means of the present embodiment and the actual toner amount (toner weight) in the toner hopper 9.
As shown in FIG. 11, it can be seen that there is little deviation of the capacitance value with respect to the actual toner amount (toner weight) in the toner hopper 9 due to the difference in toner conditions and driving conditions. Therefore, accurate toner amount detection can be realized, and there is no problem that the toner bottle is oversupplied to the toner hopper 9 or the required amount cannot be replenished.

In the present embodiment, when it is detected that the toner weight is 2 [g] or less, it is determined that there is no toner in the toner hopper 9, and a signal for replenishing the toner from the toner bottle to the toner hopper 9 is output. It is the control content to be performed. Therefore, when the capacitance value becomes 0.65 [pF] or less in the case of F2 toner or NF toner, and when the capacitance value becomes 0.63 [pF] or less in the case of CE2 toner. , It is determined that there is no toner in the toner hopper 9.

[Modification 1]
Next, a modification of the toner amount detecting means in the above-described embodiment (hereinafter, this modification will be referred to as “modification example 1”) will be described.
FIG. 12 is an explanatory diagram showing the configuration of the toner replenishing device (toner accommodating device) in the first modification.
In the above-described embodiment, the upper electrode portion 9d and the lower electrode portion 9e are provided outside the toner hopper 9, but in the present modification 1, the upper electrode portion 9d and the lower electrode portion 9e are provided on the toner hopper 9. It is a configuration provided inside. Hereinafter, the differences from the above-described embodiments will be mainly described.

The upper electrode portion 9d and the lower electrode portion 9e of the present modification 1 also use an iron plate material having a thickness of 1 [mm] as in the above-described embodiment, and are attached to the inner bottom surface and the inner top surface of the toner hopper 9. .. Therefore, the length of the agitator 9b is set to 10 [mm], which is shorter than that of the above-described embodiment, and the agitator 9b is designed so as not to hit the lower electrode portion 9e. This is to prevent toner aggregation from occurring on the lower electrode portion 9e.

By providing the upper electrode portion 9d and the lower electrode portion 9e inside the toner hopper 9 as in the first modification, the distance between the upper electrode portion 9d and the lower electrode portion 9e can be shortened and the output sensitivity is increased. , The S / N ratio is improved. Since the wall portion (resin material in this case) of the toner hopper 9 does not exist between the upper electrode portion 9d and the lower electrode portion 9e, it is not necessary to consider the dielectric constant of the wall portion (resin). The amount of toner in the toner hopper 9 can be detected more accurately than in the embodiment.

In this modification 1, both the upper electrode portion 9d and the lower electrode portion 9e are provided inside the toner hopper 9, but either one of the upper electrode portion 9d and the lower electrode portion 9e is provided in the toner hopper 9. It may be an example provided inside.

[Modification 2]
Next, another modification of the toner amount detecting means in the above-described embodiment (hereinafter, this modification will be referred to as “modification example 2”) will be described.
FIG. 13 is an explanatory diagram showing the configuration of the toner replenishing device (toner accommodating device) in the second modification.
In the above-described embodiment, the upper electrode portion 9d is a plate-shaped member provided on the outer wall surface of the top surface of the toner hopper 9, but in the present modification 2, the rotating shaft 9a supporting the agitator 9b is used as the upper electrode portion 9d. It is a composition. Hereinafter, the differences from the above-described embodiments will be mainly described. The lower electrode portion 9e of the present modification 2 is arranged inside the toner hopper 9 in the same manner as the above-described modification 1.

In the configuration in which the upper electrode portion 9d and the lower electrode portion 9e are arranged on the wall surface of the toner hopper 9 as in the above-described embodiment and modification 1, the wall portion (resin) of the toner hopper 9 changes in temperature and humidity. The distance between the upper electrode portion 9d and the lower electrode portion 9e may fluctuate accordingly. Therefore, in a situation where the temperature and humidity can change, the capacitance value measured varies with the change in temperature and humidity, and it may be difficult to accurately detect the amount of toner.

In the second modification, the rotating shaft 9a constituting the upper electrode portion 9d is not provided on the wall portion (resin) of the toner hopper 9. Therefore, even if the wall portion (resin) of the toner hopper 9 expands or contracts due to changes in temperature or humidity, the position of the rotating shaft 9a does not displace. Therefore, even in a situation where the temperature and humidity can change, the distance fluctuation between the upper electrode portion 9d and the lower electrode portion 9e can be small, and the capacitance value measured with the change in temperature and humidity fluctuates. Less and more accurate toner amount detection is possible.

[Modification 3]
Next, another modification of the toner amount detecting means in the above-described embodiment (hereinafter, this modification will be referred to as “modification 3”) will be described.
FIG. 14 is an explanatory diagram showing the configuration of the toner replenishing device (toner accommodating device) in the third modification.
In the above-described embodiment, the lower electrode portion 9e is arranged over both the agitator 9b, which is two rotating members arranged in the toner hopper 9, and the inner bottom surface portion facing each of the toner replenishment screw 9c. In the third modification, the lower electrode portion 9e1 is arranged only on the inner bottom surface portion facing the agitator 9b, and the lower electrode portion 9e2 is not arranged on the inner bottom surface portion facing the toner replenishment screw 9c. .. Hereinafter, the differences from the above-described embodiments will be mainly described.

According to the configuration of the present modification 3, the remaining amount of toner on the inner bottom surface portion facing the agitator 9b is accurately detected without being affected by the toner amount on the inner bottom surface portion facing the toner replenishment screw 9c. Can be done.

As shown in FIG. 15, the lower electrode portion 9e2 is arranged only on the inner bottom surface portion facing the toner replenishment screw 9c, and the lower electrode portion 9e1 is not arranged on the inner bottom surface portion facing the agitator 9b. May be good. In this case, the remaining amount of toner on the inner bottom surface portion facing the toner replenishment screw 9c can be accurately detected without being affected by the amount of toner on the inner bottom surface portion facing the agitator 9b.

What has been described above is an example, and has a unique effect in each of the following aspects.
[First aspect]
The first aspect is a toner accommodating device including a toner amount detecting means (for example, upper electrode portion 9d, lower electrode portion 9e, capacitance detection circuit 9f) for detecting the amount of toner in a toner accommodating portion (for example, a toner hopper 9). (For example, a toner replenishing device), wherein a rotating member (for example, an agitator 9b or a toner replenishing screw 9c) is provided in the toner accommodating portion, and the inner bottom surface of the toner accommodating portion is viewed from the axial direction of the rotating member. The toner amount detecting means is curved in a substantially arc shape, and the toner amount detecting means is based on the electrostatic capacitance between the upper electrode portion 9d and the lower electrode portion 9e arranged so as to sandwich the toner in the toner accommodating portion at the top and bottom. The lower electrode portion detects the amount of toner in the toner accommodating portion, and is characterized in that the lower electrode portion is arranged over the entire horizontal width (entire lateral direction) of the inner bottom surface when viewed from the axial direction of the rotating member. Toner.
In a toner accommodating device provided with a rotating member in the toner accommodating portion, the inner bottom surface of the toner accommodating portion is approximately circular when viewed from the axial direction of the rotating member so that the amount of toner that cannot contact the rotating member in the toner accommodating portion is reduced. Adopt a configuration that is curved in an arc shape. In the configuration provided with such a rotating member, the toner on the inner bottom surface is biased to one side in the lateral direction, or the toner on the inner bottom surface is wavy in the lateral direction, and the bulk of the toner in the lateral direction is not constant. Can change irregularly. Therefore, it is difficult to accurately detect the amount of toner in the configuration by a toner amount detecting means that can detect only the toner deposited on a part of the inner bottom surface of the toner accommodating portion in the lateral direction.
In this embodiment, in order to accurately detect the amount of toner even in such a configuration, it is based on the electrostatic capacitance between the upper electrode portion and the lower electrode portion arranged so as to sandwich the toner in the toner accommodating portion at the top and bottom. A toner amount detecting means for detecting the amount of toner in the toner accommodating portion was used, and the lower electrode portion thereof was arranged over the entire lateral direction of the inner bottom surface of the toner accommodating portion. As a result, the amount of toner can be detected based on the capacitance of the toner accommodating portion in the entire lateral direction, and even if the bulk of the toner in the lateral direction changes irregularly, the effect is affected. The amount of toner can be detected without receiving it.

[Second aspect]
The second aspect is characterized in that, in the first aspect, at least one of the upper electrode portion and the lower electrode portion is arranged inside the toner accommodating portion.
According to this, as described in the first modification, the distance between the upper electrode portion and the lower electrode portion can be shortened as compared with the configuration in which the toner is arranged outside the toner accommodating portion, and the upper electrode portion and the lower electrode portion can be shortened. By not interposing the wall portion of the toner accommodating portion between the portions as much as possible, the amount of toner in the toner accommodating portion can be detected more accurately.

[Third aspect]
A third aspect is characterized in that, in the first or second aspect, the upper electrode portion is a rotation shaft 9a of the rotating member.
When the upper electrode portion is provided on the wall surface of the toner accommodating portion, the wall portion of the toner accommodating portion expands or contracts due to changes in temperature and humidity, so that the position of the upper electrode portion is displaced and the upper electrode portion is displaced. Since the distance between the toner and the lower electrode portion fluctuates, the capacitance fluctuates as the temperature and humidity change, making it difficult to accurately detect the amount of toner.
According to this aspect, since the rotating shaft 9a of the rotating member, which is hard to be displaced even if the wall portion of the toner accommodating portion expands or contracts due to a change in temperature or humidity, is used as the upper electrode portion, the temperature or humidity changes. Even in the situation where it is obtained, the variation in the distance between the upper electrode and the lower electrode is small, and the capacitance measured with changes in temperature and humidity is less variable, enabling more accurate toner amount detection. Become.

[Fourth aspect]
In the fourth aspect, in any of the first to third aspects, the first rotating member (for example, agitator 9b) that conveys the toner in the direction orthogonal to the rotating shaft 9a and the rotating shaft are contained in the toner accommodating portion. The second rotating member (for example, the toner replenishing screw 9c) that conveys the toner in the direction is arranged so as to be substantially parallel to each other at a position where the rotation axes are displaced in the horizontal direction, and faces the first rotating member. The inner bottom surface portion of the toner accommodating portion is curved in a substantially arc shape when viewed from the axial direction of the first rotating member, and the lower electrode portion 9e1 is formed from the axial direction of the first rotating member. It is characterized in that it is arranged over the entire width of the inner bottom surface portion in the horizontal direction when viewed, and is not arranged on the inner bottom surface portion of the toner accommodating portion facing the second rotating member.
According to this, as described in the modified example 3, the remaining amount of toner on the inner bottom surface portion facing the first rotating member is not affected by the amount of toner on the inner bottom surface portion facing the second rotating member. Can be detected accurately.

[Fifth aspect]
In the fifth aspect, in any of the first to third aspects, the first rotating member (for example, agitator 9b) that conveys the toner in the direction orthogonal to the rotating shaft 9a and the rotating shaft are contained in the toner accommodating portion. The second rotating member (for example, the toner replenishing screw 9c) that conveys the toner in the direction is arranged so as to be substantially parallel to each other at a position where the rotation axes are displaced in the horizontal direction, and faces the second rotating member. The inner bottom surface portion of the toner accommodating portion is curved in a substantially arc shape when viewed from the axial direction of the second rotating member, and the lower electrode portion 9e2 is formed from the axial direction of the second rotating member. It is characterized in that it is arranged over the entire width of the inner bottom surface portion in the horizontal direction when viewed, and is not arranged on the inner bottom surface portion of the toner accommodating portion facing the first rotating member.
According to this, as described in the modified example 3, the remaining amount of toner on the inner bottom surface portion facing the second rotating member is not affected by the amount of toner on the inner bottom surface portion facing the first rotating member. Can be detected accurately.

[Sixth aspect]
A sixth aspect is an image forming apparatus that forms an image using toner supplied from a toner accommodating device (for example, a toner replenishing apparatus), and the toner according to any one of the first to fifth aspects is used as the toner accommodating device. It is characterized by using a containment device.
According to this aspect, it is possible to suppress erroneous detection of the amount of toner in the toner accommodating device adopting a configuration in which the inner bottom surface of the toner accommodating portion is curved in a substantially arc shape when viewed from the axial direction of the rotating member. Therefore, it is possible to solve the image quality problem such as the density fading due to the lack of toner caused by this false detection.

1: Photoconductor 8: Developing device 8a: Developing roller 8b: First screw 8c: Second screw 8d: Inclined screw 9: Toner hopper 9a: Rotating shaft 9b: Agitator 9c: Toner replenishing screw 9d: Upper electrode part 9e: Lower side Electrode part 9f: Capacitance detection circuit 9g: Screw 9h: Shielded wire S: Recording sheet T: Toner

Japanese Unexamined Patent Publication No. 2015-135428

Claims (6)

A toner accommodating device provided with a toner amount detecting means for detecting the amount of toner in the toner accommodating portion.
A rotating member is provided in the toner accommodating portion.
The inner bottom surface of the toner accommodating portion is curved in a substantially arc shape when viewed from the axial direction of the rotating member.
The toner amount detecting means detects the amount of toner in the toner accommodating portion based on the capacitance between the upper electrode portion and the lower electrode portion arranged so as to sandwich the toner in the toner accommodating portion.
The toner accommodating device is characterized in that the lower electrode portion is arranged over the entire width of the inner bottom surface in the horizontal direction when viewed from the axial direction of the rotating member. In the toner accommodating device according to claim 1,
A toner accommodating device, characterized in that at least one of the upper electrode portion and the lower electrode portion is arranged inside the toner accommodating portion. In the toner accommodating device according to claim 1 or 2.
The toner accommodating device, wherein the upper electrode portion is a rotation shaft of the rotating member. In the toner accommodating device according to any one of claims 1 to 3.
In the toner accommodating portion, the first rotating member that conveys toner in a direction orthogonal to the rotation axis and the second rotating member that conveys toner in the direction of the rotation axis are displaced from each other in the horizontal direction. It is arranged so that it is almost parallel at the vertical position.
The inner bottom surface portion of the toner accommodating portion facing the first rotating member is curved in a substantially arc shape when viewed from the axial direction of the first rotating member.
The lower electrode portion is arranged over the entire width of the inner bottom surface portion in the horizontal direction when viewed from the axial direction of the first rotating member, and is provided on the inner bottom surface portion of the toner accommodating portion facing the second rotating member. A toner accommodating device, characterized in that it is not arranged. In the toner accommodating device according to any one of claims 1 to 3.
In the toner accommodating portion, the first rotating member that conveys toner in a direction orthogonal to the rotation axis and the second rotating member that conveys toner in the direction of the rotation axis are displaced from each other in the horizontal direction. It is arranged so that it is almost parallel at the vertical position.
The inner bottom surface portion of the toner accommodating portion facing the second rotating member is curved in a substantially arc shape when viewed from the axial direction of the second rotating member.
The lower electrode portion is arranged over the entire width of the inner bottom surface portion in the horizontal direction when viewed from the axial direction of the second rotating member, and is provided on the inner bottom surface portion of the toner accommodating portion facing the first rotating member. A toner accommodating device, characterized in that it is not arranged. An image forming apparatus that forms an image using toner supplied from a toner accommodating apparatus.
An image forming apparatus according to any one of claims 1 to 5, wherein the toner accommodating apparatus is used as the toner accommodating apparatus.

Images