JP2001175070A - Developing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device and an image forming device capable of preventing the erroneous detection of the remaining toner amount by confirming the detecting operation, that is, whether the detecting operation by a remaining toner amount detecting means is normal or not. SOLUTION: Just after a toner hopper 5Y reaches a toner end position, the toner does not lie near a reflection polarization plate 11, because of an inertia of rotation, that is, the absence of the toner occurs. In the case a photodetecting signal is outputted from a toner end sensor 22 in such the toner absence state, it is decided that the toner end sensor 22 normally functions. On the contrary, in the case the photodetecting signal is not outputted in the toner absence state, it is decided that the toner end sensor 22 does not normally function and any abnormality occurs. In the case of deciding that it is abnormal in terms of the detection of the toner end sensor 22, an error display is displayed on a display part by a control part (neither of the parts are illustrated) so as to press a user for an inspection.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device and an image forming apparatus used for a copying machine, a facsimile, a printer, and the like, and more particularly, to a developing device for developing a latent image formed on an image carrier. A detection unit configured to detect a remaining amount of toner and configured to store toner to be supplied to the developing device; and a remaining toner detection unit having a light emitting unit and a light receiving unit. The present invention relates to a developing device and an image forming apparatus that detect the remaining amount of toner in the toner storage unit based on the amount of light reaching the light receiving unit via a detection unit for detecting the amount.

[0002]

2. Description of the Related Art Conventionally, a developing device used in an image forming apparatus is provided with a toner remaining amount detecting means having a light emitting portion and a light receiving portion. There is a known type that detects the remaining amount of toner in the toner storage unit based on the amount of light reaching the light receiving unit via the unit.

In the above-mentioned developing device, for example, a light reflection type or light transmission type toner end sensor is provided as a toner remaining amount detecting means, and light emitted from a light emitting portion of the toner end sensor is blocked by toner in a toner containing portion. Is used to detect the remaining amount of toner in the toner storage unit by utilizing the fact that the amount of light reaching the light receiving unit decreases. Therefore, if at least one of the light emitting surface and the light receiving surface of the toner end sensor is contaminated with scattered toner or the like, or at least one of the light emitting unit and the light receiving unit breaks down and malfunctions, the toner in the toner storage unit may be damaged. Even though the remaining amount is low, the output of the toner end sensor may be the same as when a sufficient amount of toner exists in the toner storage unit. In such a case, it is erroneously detected that a sufficient amount of toner remains in the toner container even though the remaining amount of toner in the toner container is low and, for example, the toner is in the toner end state. There was a problem that it would.

Accordingly, the present applicant has disclosed in Japanese Patent Application Laid-Open No. 10-3960.
In Japanese Patent Application Laid-Open No. 5 (1993) -1995, a detection section for confirming a detection operation of a toner end sensor is provided in a toner storage section in addition to a detection section for toner end detection to detect whether the detection operation by the toner end sensor is normal. A developing device that performs a checking operation is disclosed.

[0005]

However, in the developing device disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 10-39605,
Since it is necessary to provide a detected portion for checking the detection operation of the toner end sensor in addition to the detected portion for detecting the toner end in the toner storage portion, there is a possibility that the manufacturing cost may increase.

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and an object of the present invention is to check whether a detection operation by a toner remaining amount detecting means is normal or not, and to erroneously detect the remaining toner amount. It is an object of the present invention to provide a developing device and an image forming apparatus capable of preventing the occurrence of the problem.

[0007]

To achieve the above object, according to the present invention, there is provided a developing device for developing a latent image formed on an image carrier, and a detection unit for detecting a remaining amount of toner. And a toner storage unit for storing toner to be supplied to the developing device, and a toner remaining amount detecting unit having a light emitting unit and a light receiving unit. In the developing device for detecting the remaining amount of toner in the toner storage unit based on the amount of light reaching the light receiving unit, a toner existing state in which toner is present in a detected portion facing the toner remaining amount detecting means; It is configured such that the toner of the detected portion is retracted and the toner absence state is not present, and based on the detection result of the toner remaining amount detection means in the toner absence state, the toner remaining amount detection means Determine whether the detection operation is normal In which it characterized in that a determination means.

In the developing device according to the first aspect of the invention, when the toner that blocks light is not retracted to the detected portion and the toner is absent, the light emitted from the light emitting portion of the toner remaining amount detecting means is not emitted. The light reaches the light receiving section via the detected section, and the toner remaining amount detecting means outputs a light receiving signal indicating that light has been received as a detection result. At this time, when the light receiving signal is not output from the toner remaining amount detecting means,
Whether the light emitted from the light emitting unit has not reached the light receiving unit,
Alternatively, the function of the toner remaining amount detecting unit has some sort of abnormality due to a failure of the light emitting unit or the light receiving unit. In this manner, it is determined whether or not the detection operation of the toner remaining amount detecting means is normal based on the detection result of the toner remaining amount detecting means when the toner is absent.

According to a second aspect of the present invention, in the developing device of the first aspect, a developing unit which supports a plurality of sets of developing units and a toner container so as to be rotatable around a rotation axis, and a drive for driving the developing unit to rotate. Means, when the developing unit is rotated by the driving means and stopped at the toner remaining amount detection position, the toner absence state occurs,
The above-mentioned judging means makes a judgment.

In the developing device according to the second aspect, the developing unit is rotationally driven by the driving means, and after the toner is stopped at the toner remaining amount detecting position, the toner in the toner containing portion is detected by the inertia due to the rotational driving. A toner-absent state that does not exist in the portion occurs. In the absence state of the toner, the light emitted from the light emitting section of the toner remaining amount detecting means reaches the light receiving section via the detected section. Based on the detection result of the remaining toner amount detecting unit at this time, the determining unit determines the detecting operation of the remaining toner amount detecting unit.

According to a third aspect of the present invention, in the developing device according to the first or second aspect, the determining means determines the remaining amount of toner based on a plurality of detection results of the remaining toner amount detecting means. It is characterized by performing.

In the developing device according to the third aspect, when toner is accidentally present in the detected portion due to movement of the toner in the toner storage portion, the light receiving signal is output from the toner remaining amount detecting means. There is a possibility that the determination by the determination means may not be performed accurately, but the determination can be performed accurately by performing the determination based on the plurality of detection results.

According to a fourth aspect of the present invention, there is provided a latent image carrier, a latent image forming means for forming a latent image on the latent image carrier, and a developing means for developing the latent image on the latent image carrier. In the image forming apparatus provided with the developing device, the developing device according to claim 1, 2 or 3 is used as the developing unit.

According to the image forming apparatus of the fourth aspect, the developing device can form an image while reliably detecting toner.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a rotary developing device to which the present invention is applied will be described with reference to the drawings.
FIG. 1A is a perspective view illustrating a developing device according to the present embodiment. FIG. 1B is a perspective view showing a rotating support of the developing device. FIG. 1C is a perspective view showing a set of a developing device and a toner hopper as a toner container of the developing device. In the image forming section of the image forming apparatus having the rotary developing device 1, in addition to the developing device 1, a photoconductor as a latent image carrier (not shown), a charging device and an optical device as a latent image forming unit, and a charge elimination device It is equipped with devices. The image forming apparatus further includes a control unit (not shown) other than the image forming unit,
A driving device for the developing device, a fixing device, and the like are provided.
The developing device 1 includes a rotating support 2 and four
Yellow (Y), cyan (C), magenta (M),
And developing devices 3Y, 3C, 3M, and 3B which are detachably mounted for developing the respective toners of black (B). Further, these developing units are integrally mounted with toner hoppers 5Y, 5C, 5M and 5B, respectively. The rotary support 2 has a developing device support plate 2b and a toner hopper support plate 2c fixed to a rotation shaft 2a so as to be orthogonal to each other, and a disc-shaped side plate is attached to an end of the developer support plate 2b. A disc-shaped side plate portion 2e is fixed between the portion 2d and the developing device support plate 2b and the toner hopper support plate 2c.

Next, the developing units 3Y, 3C, 3M, 3B
The configurations of the toner hoppers 5Y, 5C, 5M, and 5B will be described. Note that the toner hoppers 5Y, 5C, 5M,
Since 5B has the same configuration, a description will be given below of a developing device 3Y using yellow (Y) toner and a toner hopper 5Y by adding a suffix Y to each member. In the developing device 3Y, a developing roller 30Y, a toner supply roller (not shown), and a blade are disposed in the longitudinal direction. The toner hopper 5Y has a peripheral wall 51Y having a predetermined width in the axial direction of the rotary shaft 2a and a front and rear side wall 52Y having a circular outer periphery of the rotary support when viewed from the front. And the V-shaped bottom wall 53Y
(See FIG. 2A). Toner hopper 5
Y communicates with the developing device 3Y so that toner is supplied from the toner hopper 5Y to the developing device 3Y. The toner hopper 5Y, the toner hopper 5C, the toner hopper 5M, and the toner hopper 5B have a circular outer periphery as a whole when viewed from the front.

FIG. 2A is an explanatory view of the inside of the toner hopper 5Y and the toner end sensor 22 composed of an optical sensor as viewed from the front. FIG. 2B is a perspective view showing an optical member for toner detection and a cleaning member for cleaning an exposed surface of the optical member through which light can pass. As the toner end sensor 22, a sensor having a light emitting unit 20 and a light receiving unit 21 is used. At the center of the rotation support of the peripheral wall 51Y of the toner hopper 5Y, a pair of optical members for toner detection are provided as a reflective polarizer 11Y on the light receiving side of the toner end sensor 22 and a reflective polarizer 12Y on the light emitting side of the toner end sensor 22. Are provided to face each other. The reflective polarizing plate 11Y and the reflective polarizing plate 12Y have a rectangular shape of a rotating support, and have a light-transmitting light-exposing-side exposed surface facing the toner detection area on the light-receiving side of the toner end sensor 22 (hereinafter, “light-receiving-side exposed surface”). 1)
10Y, a light incident side exposed surface (hereinafter referred to as a “light emitting side exposed surface”) 120Y facing the toner detection area on the light emitting side of the toner end sensor 22 and a light receiving side exposed surface 1
The reflecting surface 111Y and the reflecting surface 12 each have a 45-degree inclination angle with respect to 10Y and the light-emitting side exposed surface 120Y and reflect light.
1Y. These light receiving side exposed surfaces 1
The light propagation path in the toner hopper between 10Y and the light-emitting side exposure surface 120Y forms a toner detection area.

Further, the cleaning member comprises a reflective polarizing plate 11.
A plate-shaped scraper 18Y as a cleaning unit for cleaning the exposed surfaces 110Y and 120Y of the Y and 12Y;
A scraper support 17Y as a support that swings while supporting 8Y. The scraper support 17Y supports and swings the scraper 18Y so that the scraper 18Y moves along the exposed surface in a state of contacting or approaching the exposed surface in accordance with the rotation of the toner hopper 5Y. In the vicinity of one side of the reflective polarizing plates 11Y and 12Y, a support portion 13 for supporting the scraper support portion 17Y is provided.
Y and 14Y protrude. These support portions 13Y
And 14Y are provided with support holes 130Y and 140Y, and a groove 131Y and a groove 141Y are formed above the support holes.
Is provided. These support holes 130Y and 140
A support shaft 15Y is supported on Y. The support shaft 15Y has a cylindrical member 1 having a diameter slightly larger than the diameter of the support shaft 15Y.
6Y is loosely inserted. The length of the cylindrical member 16Y is smaller than the interval between the support portions 13Y and 14Y, and has a predetermined play in the axial direction. A scraper support 17Y is fixed to the center of the rotary support of the tubular member 16Y, and the scraper support 17Y is a semicircular free end 17 of the rotary support.
0Y and a rotating support fan-shaped base 171Y.
A groove 172 is provided in the base 171Y of the scraper support 17Y.
Y is provided, and a scraper 18Y, which is a plate-like member having a rectangular shape of a rotation support member, is fitted into the groove 172Y. The width W1 of the scraper 18Y is smaller than the distance W2 between the light receiving side exposed surface 110Y of the reflective polarizing plate 11Y and the light emitting side exposed surface 120Y of the reflective polarizing plate 12Y. Therefore, even if the cylindrical member 16Y is pivoted on the support shaft 15Y in the axial direction by one play only in the axial direction, the scraper 18
Y is a light-exposing-side exposed surface 110Y of the reflective polarizing plate 11Y or a light-emitting-side exposed surface 120Y of the reflective polarizer 12Y.
And is slid in contact with one of the surfaces.

When the developing device 3Y and the toner hopper 5Y attached to the developing device 3Y are at the toner detecting position, a sensor mounting portion is provided on the main body side of the peripheral wall 51Y of the toner hopper 5Y facing the toner detected portion. Have been. A light emitting unit (infrared LED) 20 for emitting light is provided on the sensor mounting unit.
And a light receiving unit (light receiving element for remote control) 2 for receiving this light
1 is attached. The light emitting section 20 and the light receiving section 21 constitute a toner end sensor 22. In the above configuration, when the toner is not contained in the toner hopper 5Y, as shown in FIG. 3A, when the toner end sensor 22 emits light from the light emitting unit 20, the emitted light enters the reflective polarizing plate 12Y. I do. Reflective polarizing plate 12
The light that has entered Y is reflected by the reflecting surface 121Y and exits from the light emitting side exposed surface 120Y. The emitted light is not blocked by the toner, and enters the light receiving side exposed surface 110Y. Reflective polarizing plate 1
The light that has entered 1Y is reflected by the reflecting surface 111Y and exits from the reflective polarizing plate 11Y. When the emitted light reaches the light receiving unit 21, the toner end sensor 22 transmits a light receiving signal to a control unit (not shown). The control unit determines that there is no toner in the toner hopper 5Y based on the light receiving signal from the toner end sensor 22. Further, when toner is contained in the toner hopper 5Y, as shown in FIG. 3B, when the toner end sensor 22 emits light from the light emitting unit 20,
The emitted light enters the reflective polarizer 12. The light that has entered the reflective polarizing plate 12Y is reflected by the reflective surface 121Y and exits from the light-emitting side exposed surface 120Y. The emitted light is blocked by the toner. For this reason, the light receiving unit 21 cannot receive a predetermined amount of light, and the toner end sensor 22 does not transmit a predetermined light receiving signal to the control unit. Therefore, the control unit determines that toner is present in the toner hopper 5Y.

Next, the state of the toner in the toner hopper with the rotation of the rotary developing device 1 will be described. FIG.
(A) is a sectional view in a front view showing a state of toner in the toner hopper 5Y at a developing position. FIG. 4B is a cross-sectional front view showing the state of the toner in the toner hopper 5Y at the toner end detection position. FIG. 4 (c)
FIG. 6 is a front sectional view showing a state of toner immediately after the toner hopper 5Y stops at the toner end detection position.

When the toner hopper 5Y is at the developing position, as shown in FIG. 4A, the toner is transferred to the toner hopper 5Y by the partitioning plate 54Y provided in the toner hopper 5Y by utilizing the rotating operation of the developing device 1. It is efficiently conveyed to the communication port 55Y that communicates with the developing device 3Y. Then, the toner is moved from the communication port 55Y to the developing device 3Y, and the remaining toner in the toner hopper 5Y is reduced as much as possible. When the toner hopper 5Y is located at the developing position, the last remaining toner is near the communication port 55Y. Therefore, the presence / absence of toner in this portion is determined by the toner end sensor 22 (see FIG. At the bottom). Therefore, when the toner hopper 5Y is at the toner end detection position next to the developing position, the presence or absence of toner in the hopper is detected.

After a predetermined time has elapsed after the developing device 3Y has rotated and the toner hopper 5Y has stopped at the toner end detection position, as shown in FIG. 4B, the toner in the toner hopper 5Y follows the curvature of the peripheral wall 51Y. The toner is present at the bottom. Reflective polarizing plate 11 for detecting toner end
Since Y is provided at the lowermost portion where the toner gathers, if the toner end detection is performed in a state where the toner is present, the detection can be performed in a state where there is no residual toner in the toner hopper 5Y.

Immediately after the toner hopper 5Y reaches the toner end detection position and before the toner is present, as shown in FIG. 4C, the toner in the toner hopper 5Y reaches its maximum due to inertia. There is no toner at the periphery of the reflective polarizing plate 11Y without being collected at the lower portion, and the toner is absent. Toner hopper 5 according to the illustrated example
In Y, at least 1 after reaching the toner end detection position.
A toner absent state of about 1/100 second can occur. In this toner absence state, the light emitting unit 2 of the toner end sensor 22
The light emitted from 0 is not blocked by the toner, reaches the light receiving unit 21, and the toner end sensor 22 transmits a light receiving signal to a control unit (not shown).

In the present embodiment, the light receiving signal output from the toner end sensor 22 when the toner hopper 5Y reaches the toner end detection position when the toner is absent is used for the self-check function of the toner end sensor 22. I have. More specifically, if a light receiving signal is output from the toner end sensor 22 when the toner is absent, it is determined that the toner end sensor 22 is functioning normally. On the other hand, if no light receiving signal is output in the toner absence state, the toner end sensor 22
Is not functioning properly and it is determined that there is some abnormality. When it is determined that there is an abnormality in the detection of the toner end sensor 22, an error display is displayed from the control unit on a display unit (not shown) to urge the user to perform an inspection.

The sequence of toner end detection is performed by the toner end sensor 2 immediately after the toner end detection position is reached.
The output of the light receiving signal of No. 2 and the output after a certain time has elapsed can be recognized separately. Then, the output in the toner absence state immediately after reaching the toner end detection position is used for checking the function of the toner end sensor 22, and the output after a certain period of time is used for the original toner end detection. In the image forming apparatus according to the present embodiment, the time during which each developing device is stopped at the toner end detection position is about 2 seconds. Therefore, the first 1 second is used for the toner end sensor self-check function. The second second is used for toner end detection. That is, a light receiving signal is output from the toner end sensor 22 during the first second, and if the signal changes instantaneously, it is determined that the toner end sensor 22 is functioning normally. If there is no change, there is an abnormality. Is determined.

In the toner end sensor self-check function, malfunction of the self-check function itself is prevented. More specifically, a toner end detection operation is performed a plurality of times for a predetermined color developing unit (for example, 100 consecutive times).
The toner end sensor 2 in the toner absence state immediately after the toner hopper reaches the toner end detection position.
The sequence is such that when there is no output of the light receiving signal from the second, it is determined that the function of the toner end sensor 22 is abnormal.

As described above, according to the present embodiment, it is possible to determine whether or not the detection operation of the toner end sensor is normal based on the detection result of the toner end sensor in the absence of toner immediately after reaching the toner end detection position. Therefore, erroneous detection of toner end of the toner hopper can be prevented. Furthermore, since the toner between the pair of reflective polarizers, which is the detected part, retreats due to the inertia due to the rotational driving of the toner hopper and a toner-absent state occurs, a special device for setting the detected part to the toner-absent state is provided. There is no need to provide them, and cost can be reduced.

In the above embodiment, an example in which the present invention is applied to a developing device having four developing devices has been described. However, a developing device having one developing device or a developing device having a plurality of developing devices other than four developing devices is described. Is similarly applicable. Here, in the case of a configuration in which the developing device is not moved, such as a developing device having a single developing device, since the toner hopper does not move with respect to the toner end sensor, a stirring member such as an agitator in the toner hopper is used. It is conceivable to employ a configuration in which the toner in the toner detection area between the pair of reflective polarizing plates is retracted.

[0029]

According to the first to fourth aspects of the present invention, the detection result of the toner remaining amount detecting means in the toner absence state where the toner for shielding light does not retreat in the detected portion does not exist. Since it is possible to determine whether or not the detection operation of the toner remaining amount detecting means is normal based on the above, it is possible to prevent erroneous detection of the toner remaining amount in the toner storage unit beforehand, and it is possible to perform toner detection with high accuracy. Has an effect.

In particular, according to the second and third aspects of the present invention, it is determined whether or not the detection operation of the toner remaining amount detecting means is normal in the toner absence state after the stop of the developing unit. There is no need to provide a special device for retracting the toner in the portion, and there is an excellent effect that the cost can be reduced.

In particular, according to the third aspect of the present invention, since the determination means makes a determination based on a plurality of detection results of the remaining toner amount detection means, erroneous determination by the determination means can be prevented. Has an excellent effect.

In particular, according to the invention of claim 4, since the image formation can be performed while reliably detecting the toner in the toner container, there is an excellent effect that a high quality image can be formed. .

[Brief description of the drawings]

FIG. 1A is a perspective view showing a developing device according to an embodiment of the present invention. (B) is a perspective view showing a rotation support of the developing device. (C) is a perspective view showing a developing unit of the developing device.

FIG. 2A is a schematic sectional view of a toner end sensor including a toner hopper and an optical sensor of the developing device as viewed from the front. (B) is a perspective view of a toner detecting optical member and a cleaning member in the toner hopper.

FIG. 3A is an explanatory diagram of toner detection by a toner end sensor when no toner is contained in the toner hopper. FIG. 3B is an explanatory diagram of toner detection by a toner end sensor when toner is contained in the toner hopper.

FIG. 4A is a front sectional view showing a state of toner in a toner hopper at a developing position. FIG. 4B is a front cross-sectional view illustrating a state of the toner in the toner hopper at the toner end detection position. FIG. 3C is a front sectional view showing the state of the toner immediately after the toner hopper stops at the toner end detection position.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 developing device 2 rotating support 3 developing device 5 toner hopper 11 reflective polarizing plate on light receiving side 12 reflective polarizing plate on light emitting side 15 support shaft 17 scraper support portion 18 scraper 20 light emitting portion 21 light receiving portion 22 toner end sensor 110 light receiving side exposure Surface 111 Reflective surface 120 Light emitting side exposed surface 120 Reflective surface

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H027 DD02 DE02 DE07 DE10 EA06 EB04 EC06 EC07 EC09 EC10 ED10 EF02 HA02 HA04 HA13 HB13 HB20 2H030 AD01 AD17 BB02 BB24 BB33 BB38 2H077 AA12 BA01 BA08 BA09 DA16 DA65 DA63 DA63 DA63 DA63 DA63 DA63 DA63 DA63 DA63 DA63 DA63 DA63 DA63 DA63 DA63 DA GA13

Claims (4)

[Claims] A developing device for developing a latent image formed on an image carrier; a toner storage portion having a detection portion for detecting a remaining amount of toner and storing toner to be supplied to the development device; A toner remaining amount detecting means having a light receiving portion and a light receiving portion. The amount of light reaching the light receiving portion from the light emitting portion via the detection portion for detecting the remaining toner amount is used to detect the amount of toner remaining in the toner containing portion. In the developing device for detecting the amount of toner, it is possible to take a toner existing state where toner is present in the detected part facing the toner remaining amount detecting means and a toner absence state where the toner in the detected part is retracted and does not exist. And determining means for determining whether or not the detection operation of the remaining toner amount detecting means is normal based on the detection result of the remaining toner amount detecting means when the toner is absent. Developing device. 2. The developing device according to claim 1, further comprising: a developing unit that supports a plurality of sets of developing units and a toner container so as to be rotatable around a rotation axis; and a driving unit that drives the developing unit to rotate. The developing device is characterized in that the determination unit makes a determination when the toner absence state occurs after the development unit is rotated by the driving unit and stopped at the toner remaining amount detection position. 3. The developing device according to claim 1, wherein said determination means determines the remaining toner amount based on a plurality of detection results of said remaining toner amount detection unit. Developing device. 4. An image forming apparatus comprising: a latent image carrier; a latent image forming means for forming a latent image on the latent image carrier; and a developing means for developing the latent image on the latent image carrier. 4. An image forming apparatus according to claim 1, wherein the developing device according to claim 1, 2 or 3 is used as said developing means.