JP2002091155A - Developing unit and developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hardly cause faulty development even when a developing unit is inclined in the longitudinal direction of a developing roller and to prevent a toner end from being detected even though some toner remains more than necessary. SOLUTION: The internal shape of the flat developing unit 10 is formed so that toner capacities on a side where a toner sensor 21 is provided and on an opposite side thereto with respect to a center part C in a width direction may be small. As for the internal shape, the inner wall shape of a case 11 is made different between on the side where the toner sensor is provided and on the opposite side thereto with respect to the center part, or the shape of an agitator is made different between on the side where the toner sensor is provided and on the opposite side thereto.

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 a developing device in an image forming apparatus such as a printer, a facsimile, and a copying machine for forming an image by using an electrophotographic technique. In particular, the present invention relates to a technique for detecting the remaining amount of toner.

[0002]

2. Description of the Related Art Generally, an image forming apparatus for forming an image by using an electrophotographic technique has a photosensitive member as an image carrier having a photosensitive layer on an outer peripheral surface, and uniformly charges the outer peripheral surface of the photosensitive member. A charging unit, an exposure unit for selectively exposing the outer peripheral surface of the photoreceptor uniformly charged by the charging unit to form an electrostatic latent image, and an electrostatic latent image formed by the exposure unit. And a developing device having a developing device that applies a toner as a developer to form a visible image (toner image).

[0003] A developing device includes a case containing toner,
A developing roller rotatably supported by the case and applying toner to the photoconductor is provided. If the amount of toner in the case becomes too small, development failure occurs. Therefore, the case is provided with a toner sensor for detecting the remaining amount of toner contained in the case.

[0004]

In the conventional developing device described above, the mounting position of the toner sensor is based on the idea that the amount of toner in the case is not so small that there is no need to cause development failure. On the premise that the image forming apparatus is installed in a horizontal state by a user, the image forming apparatus is mounted at a position that is easy to design according to the shape and structure of the developing device. For this reason, the toner sensor is not provided substantially at the center in the longitudinal direction and the height direction of the developing roller in the case. It is provided at a position deviated upward or downward from. In this specification, the term "central portion in the height direction" means a position at which the toner sensor stops detecting the toner when the amount of toner is approximately half of the maximum amount of toner that can be accommodated in the case. On the other hand, it is rare that an image forming apparatus provided with a developing device (developing device) is surely installed in a horizontal state by a user, and the installed state usually has a slight inclination. In such a situation, when the image forming apparatus is installed by the user in a state of being inclined in the longitudinal direction of the developing roller of the developing device,
The following problems were found to occur.

FIGS. 11A and 11B are conceptual diagrams for explaining the above problem. FIGS. 11A, 11B, and 11C show cases 1 of the developing device.
Is a cross-sectional view of the developing roller (not shown),
(E) is a plan view of (a), and (f) is a side view of (e). In the drawing, reference numeral 1 denotes a case, 2 denotes a toner sensor, and a portion T indicated by oblique lines denotes toner. As shown in FIG. 2A, the toner sensor 2 is provided at a position deviated leftward from a center C in the longitudinal direction (left-right direction in the figure) of the developing roller and deviated downward from a center in the height direction. Have been. FIG. 1A shows the case where the image forming apparatus, that is, the developing device (and thus the case 1) is installed horizontally with respect to the longitudinal direction of the developing roller (the left-right direction in the figure), and FIG. The side opposite to the side (right side) is inclined downward, and FIG. 3C shows the case where the side where the sensor 2 is biased is inclined downward.

As shown in FIG. 1A, when the image forming apparatus, that is, the case 1 is set horizontally with respect to the longitudinal direction of the developing roller, no problem occurs. For example, as shown in FIG. × 20cm, depth 10c
m, and the mounting position of the sensor 2 is 3 cm from the bottom surface 1 a of the case 1 and 5 cm to the left from the center C in the left-right direction. The remaining amount of toner T is 600cm
It becomes ³ .

On the other hand, when the unit is omitted in the following description, for example, as shown in FIG. 1B, the case 1 is arranged so that the side (right side) opposite to the side where the sensor 2 is biased in the left-right direction is lower. Is inclined by 45 °, the amount of toner remaining is 1300, and conversely, the case 1 is inclined by 45 ° so that the side where the sensor 2 is biased is downward in the left-right direction as shown in FIG. Is 320 when remaining
Becomes In other words, in the case of FIG. 9A, when the remaining amount of toner reaches 600, the sensor 2 detects that the remaining amount of toner has decreased (this detection is referred to as toner end detection). In the case of b), it is detected when the remaining amount of toner reaches 1300, and in the case of FIG. Therefore, the difference between the remaining amount of toner in the case of FIG. (A) and the case of FIG. (B) is 900, and the difference in the remaining amount of toner between the case of FIG. The difference between the remaining amount of toner in the case of FIG. (B) and the case of FIG.
Becomes In the case of FIG. 3C, no toner end is detected on the side 1c opposite to the side on which the sensor 2 is biased in the left-right direction even though the toner is exhausted. Occurs, and conversely, in the case of FIG.
There is a problem that the toner end is detected even though a large amount of toner remains. Further, in the case of FIG. 2B, a developing defect also occurs on the side 1b where the sensor 2 is biased in the left-right direction.

In the illustrated example, the angle of inclination of the case 1 is set to 45 ° in order to easily understand such a problem. However, the same problem occurs even when the angle of inclination is small. In particular, when the width of the image forming area (the left-right direction in the figure) is wide (therefore, when the developing roller is long), or when the case 1 of the developing device is flat as shown in FIG.
No. -152303), the above-mentioned problem appears remarkably even when the inclination angle is small. In FIG. 13, 3 is a developing roller,
Reference numeral 4 denotes a photosensitive member that carries a latent image to be developed.

The above problem will be described from another point of view. As shown in FIG. 12B, when the developing device is inclined downward by more than about 30 ° to the right, toner end is not detected. Nevertheless, development failure occurs on the left side 1b (the remaining amount of toner at the time of toner end detection is about 115
0), as shown in FIG. 7C, if the inclination is about 11 ° or more downward to the left, development failure occurs on the right side 1c even though the toner end is not detected (the remaining amount of toner at the time of toner end detection). Is about 400). That is, the magnitude of the inclination angle at the time when the development failure occurs greatly differs depending on the difference in the inclination direction. Also, the developing device is
As shown in FIG. 12 (b), the amount of remaining toner at the time of toner end detection is about 1150 when inclined to the lower right by about 30 °, and about 11 to the lower left as shown in FIG. 12 (c). °
The remaining amount of toner at the time of detecting the toner end when inclined is about 400, and a large difference (1150-400 =
750) occurs. In other words, in the case of FIG. 2B, even if the case 1 is relatively large and tilts by about 30 °, no developing failure occurs. In this case, the remaining toner amount at the time of detecting the toner end is about 1150. That is, the toner end detection is performed even though an unnecessarily large amount of toner remains. However, in practice,
The number of developing units (that is, image forming apparatuses) is 30 by the user.
Since it is difficult to imagine that the developing unit is inclined at an angle of about 15 °, when the developing unit is inclined by about 15 ° as shown in FIG.
It becomes 0. Therefore, when compared with the case of FIG.
The difference between the remaining toner amounts is 850−400 = 450, but the difference is still large.

The above problem can be solved by providing the toner sensor 2 in the case 1 at a substantially central portion in the longitudinal direction and the height direction of the developing roller. 2 in case 1
As described above, it is often not always easy to provide the developing roller at a substantially central portion in the longitudinal direction and the height direction depending on the shape and structure of the developing device. It must be provided at a position deviated from the central portion in the direction and the height direction.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and to provide a developing device in which a toner sensor is provided at a position deviated from a central portion in a longitudinal direction and a height direction of a developing roller. Provided are a developing device and a developing device in which poor development hardly occurs even when inclined in the direction, and toner end detection is not performed even though a large amount of toner remains unnecessarily. It is in.

[0012]

According to a first aspect of the present invention, there is provided a developing device, comprising: a case; a developing roller rotatably provided with respect to the case; A toner sensor for detecting a remaining amount of toner, wherein the toner sensor is provided at a position deviated from a central portion in the longitudinal direction and the height direction of the developing roller in the case. Is characterized in that, with respect to the central portion in the longitudinal direction, the toner capacity on the side opposite to the side where the toner sensor is provided is reduced. The developing device according to claim 2 is the developing device according to claim 1,
The inner shape is configured such that the inner wall shape of the case is changed with respect to the central portion in the longitudinal direction between the side where the toner sensor is provided and the opposite side, so that the toner capacity on the opposite side is reduced. It is characterized by having. According to a third aspect of the present invention, in the developing device according to the first aspect, an agitator for agitating the toner is provided in the case, and the internal shape is the same as that of the agitator in the longitudinal center portion. The feature is that the toner capacity on the opposite side is reduced by changing between the side on which the toner sensor is provided and the opposite side. The developing device according to claim 4 is the developing device according to claim 1, 2, or 3,
It is characterized in that the case has a flat shape. The developing device according to claim 5, wherein the case, a developing roller rotatably provided with respect to the case, a plurality of agitators that convey toner stored in the case toward the developing roller, A toner sensor for detecting the remaining amount of toner contained in the case, wherein the toner sensor is provided in the case at a position deviated from a central portion in the longitudinal direction and the height direction of the developing roller in the case. In a developing device having a plurality of developing devices with different inverted angles, a developing device having a relatively large inverted angle is provided with a toner sensor for the inner wall shape of the case with respect to the central portion in the longitudinal direction. By changing between the opposite side and the opposite side, the toner capacity on the opposite side is reduced, and the inverted angle is relatively small. The container is configured so that the toner capacity on the opposite side is reduced by changing the shape of the agitator between the side where the toner sensor is provided and the opposite side with respect to the central portion in the longitudinal direction. It is characterized by.

[0013]

According to a first aspect of the present invention, there is provided a developing device including a case, a developing roller rotatably provided with respect to the case, and a toner sensor for detecting a remaining amount of toner contained in the case. A developing device in which the toner sensor is provided at a position deviated from a central portion in the longitudinal direction and the height direction of the developing roller in the case;
The internal shape of the developing device is related to the central portion in the longitudinal direction,
Since the configuration is such that the toner capacity on the side opposite to the side where the toner sensor is provided is reduced, even if the developing device is tilted in either the left or right direction in the longitudinal direction of the developing roller, the toner end is detected. The difference in the remaining amount of toner at the time when the operation is performed is smaller than in the related art. Therefore, it is possible to reduce the degree of occurrence of a situation in which the toner end is detected even though the toner remains in an unnecessarily large amount due to the difference in the inclination direction of the developing device (when the developing unit is inclined to any direction). It becomes possible. Therefore, as a result, even when the developing device is inclined to the left or right with respect to the longitudinal direction of the developing roller, it is possible to make it difficult to cause defective development (that is, to increase the range of inclination where no defective development occurs). Is possible). According to the developing device described in claim 2, in the developing device described in claim 1, the inner shape is such that the inner wall shape of the case is opposite to the side where the toner sensor is provided with respect to the longitudinal center portion. Since the toner capacity on the opposite side is reduced by changing the toner capacity on the opposite side, the toner capacity on the opposite side is easily reduced as compared with the case where the shape of the agitator is changed as in claim 3. It becomes possible to be constituted so that it may become. Therefore, the degree of freedom of the agitator shape can be ensured. According to a third aspect of the present invention, in the developing device of the first aspect, an agitator for agitating the toner is provided in the case, and the internal shape is the same as that of the agitator in the longitudinal direction. Regarding the central part,
By changing between the side where the toner sensor is provided and the opposite side, the toner capacity on the opposite side is reduced, so that the inner wall shape of the case can be made common. When the inner wall shape of the case is changed as described in claim 2 in the case where a plurality of agitators are provided, the toner may not be smoothly transported by the agitator. In addition, when the configuration is such that the toner capacity on the opposite side is reduced by changing the shape of the agitator, such a fear is eliminated.
According to the developing device of the fourth aspect, in the developing device of the first, second, or third aspect, the case has a flat shape, so that the image forming apparatus forms a full-color image. For example, a plurality of developing units can be easily arranged in the vertical direction. As described above, when the case has a flat shape, the above-described problem is likely to occur. According to the developing device of the fourth aspect, as described in the first, second, or third aspect, Therefore, even if the case has a flat shape, development failure due to the inclination in the longitudinal direction of the developing roller is less likely to occur regardless of the inclination direction. It is possible to reduce the degree of occurrence of a situation in which toner end detection is performed despite remaining toner. That is, the configuration of claim 1, 2, or 3 is particularly effective when the case has a flat shape. According to the developing device of the present invention, since a plurality of developing devices are provided at different angles of inversion, it is possible to reduce the size of the photosensitive member or the like as a carrier of the latent image to be developed. Becomes And each developing unit is
A case, a developing roller rotatably provided with respect to the case, a plurality of agitators for transporting the toner stored in the case toward the developing roller, and a residual toner stored in the case. A toner sensor for detecting the amount, wherein the toner sensor is
In spite of being provided at a position deviated from the central portion with respect to the longitudinal direction and the height direction of the developing roller, the internal shape of the developing device is different from the side where the toner sensor is provided with respect to the central portion in the longitudinal direction. The configuration is such that the toner capacity on the opposite side is reduced, so that even if these developing units are tilted to the left or right in the longitudinal direction of the developing roller, the residual toner at the time when the toner end is detected is detected. The difference in the amount is smaller than before. Therefore, it is possible to reduce the degree of occurrence of a situation in which the toner end is detected even though the toner remains in an unnecessarily large amount due to the difference in the inclination direction of the developing device (when the developing unit is inclined to any direction). It becomes possible. Therefore, as a result, even when the developing device is inclined to the left or right with respect to the longitudinal direction of the developing roller, it is possible to make it difficult to cause defective development (that is, to increase the range of inclination where no defective development occurs). Is possible). Further, with respect to the developing device having the relatively large inverted angle, the shape of the inner wall of the case is changed between the side where the toner sensor is provided and the opposite side with respect to the central portion in the longitudinal direction, so that the opposite side is formed. Since the toner capacity is reduced, the toner capacity on the opposite side can be easily reduced as compared with the case where the shape of the agitator is changed, and the degree of freedom of the agitator shape is secured. It is possible to do. As described above, when the developing device has a plurality of agitators and the inner wall shape of the case is changed, the toner may not be smoothly transported by the agitator as described above. Since the developing device in which the inner wall shape of the case is changed is a developing device having a relatively large inverted angle, even when the inner wall shape of the case is changed, the toner can be smoothly transported with the help of the free fall. Will be done. On the other hand, in the developing device having the relatively small inverted angle, the shape of the agitator is changed between the side where the toner sensor is provided and the opposite side with respect to the central portion in the longitudinal direction, so that the toner capacity on the opposite side is changed. Is reduced so that the shape of the inner wall of the case can be shared. In addition, the toner is smoothly transported.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> FIG. 1 is a schematic front sectional view showing a main part of an example of an image forming apparatus using a developing device and a developing device according to a first embodiment of the present invention.

The image forming apparatus includes a photosensitive member 5 as an image carrier having a photosensitive layer on the outer peripheral surface, a charging unit (not shown) for uniformly charging the outer peripheral surface of the photosensitive member 5, and one charging unit. Exposure means (not shown) for selectively exposing the outer peripheral surface of the photoreceptor 5 charged in the above manner to form an electrostatic latent image, and a developing agent on the electrostatic latent image formed by the exposure means A plurality of (four in the illustration) developing units 10 (Y, C, M,
K).

Each of the developing devices 10 is mounted on a mounting table 30 and is swingably attached to a frame (not shown), and only a developing device corresponding to the color of an image to be formed has a driving mechanism (not shown). Thereby, the photosensitive member 5 can be contacted. Reference numeral 40 (Y, C, M, K) denotes a toner cartridge for replenishing toner to the case of the developing device 10, which is detachably attached to the developing device 10.

Since the basic construction of each developing unit 10 is the same, the developing unit 10C for cyan will be described as a representative with reference to FIGS. The developing device 10 includes a case 11 and a developing roller 1 that is rotatably supported by side plates 11 a and 11 a of the case 11 about a shaft 12 b and applies toner to the photoconductor 5.
2 and a toner sensor 21 for detecting the remaining amount of toner (see T in FIG. 1) stored in the case 11. The case 11 includes a lower case 11e and an upper case 11f, and has a flat shape as a whole.

The developing roller 12 is driven to rotate in a direction indicated by an arrow in FIG. 2 at a peripheral speed of, for example, about 360 mm / s by driving means (not shown). The case 11 has first and second agitator chambers 13 and 14 and a developing chamber 15 for storing toner to be supplied to the developing roller 12. In the first and second agitator chambers 13 and 14, there are provided first and second agitators 16 and 17 which are driven to rotate in the direction of the arrow in FIG. 2 by driving means (not shown). The agitator constitutes a feeding unit that feeds the toner toward the developing roller 12 (toward the developing chamber 15). In the developing chamber 15, a supply roller 18 for supplying toner to the surface 12a of the developing roller 12 is provided. The supply roller 18 is driven to rotate in a direction indicated by an arrow in FIG. 2 by a driving unit (not shown) at a peripheral speed of, for example, about 240 mm / s.

The first and second agitator chambers 13 and 14 communicate with each other through a toner flow path (communication port) 13a, and the second agitator chamber 14 and the developing chamber 15 communicate with each other through a toner flow path (communication port) 14a.
In communication.

A blade 19 for regulating the amount of toner supplied to the surface 12a of the developing roller 12 is in contact with the surface. The blade 19 is attached to the case 11 via the support plate 20. On the opposite side of the blade 19, between the surface 12 a of the developing roller 12 and the case 11, there is provided a seal member 23 made of a thin sheet that slides on the developing roller surface 12 a. Seal member 2
3 is fixed to the case 11.

The toner sensor 21 is, as shown in FIG.
In the case 11, the developing roller 12 is provided at a position deviated from the central portion C in the longitudinal direction (left-right direction in FIG. 3) of the developing roller 12 and also deviated from the central portion in the height direction. In FIG. 1, the cross hatched portion T
(Y, C, M, K) are toners remaining in the case 11 at the time of toner end detection. Toner sensor 21
As shown in FIG. 3, is provided at a position far from the developing roller 12 in the developing device 10, in this embodiment, at a rear end portion.
The toner supply port 10a to the first side 1 is provided at a central portion C on the side of the toner sensor 21 with respect to the longitudinal direction of the developing roller 12 (left and right direction in FIG. 3). The toner sensor 21 can be constituted by a known sensor, for example, a piezoelectric powder level sensor using piezoelectric ceramics as a sensor element.

The toner cartridge 40 includes a case 41 containing toner (not shown), two agitators 42 and 43 provided in the case 41, and a case 41.
The agitators 42 and 43, which are rotationally driven in the direction of the arrow in FIG. 2 by driving means (not shown), provide a feeding means for feeding toner toward the developing device 10. Make up. Such a toner cartridge 40 is connected to the side plate rear portions 11b, 11b of the developing device 10.
2 (only one is shown in FIG. 2), the supply port 44 faces the toner supply port 10 a provided in the developing device 10, and the toner in the toner cartridge 40 loses its own weight and the agitator 42. , 43 are supplied to the developing device 10 through the supply port 44 and the toner supply port 10a.

Therefore, the toner in the toner cartridge 40 is supplied to the toner supply port 10 as indicated by the arrow t1.
a into the first agitator chamber 13 of the developing device 10 from
As shown by an arrow t1a (see FIG. 3), it spreads right and left in the first agitator chamber 13, and flows into the second agitator chamber 14 through the communication port 13a as shown by an arrow t2 while being stirred by the first agitator 16. And the second agitator 17
The developer is supplied into the developing chamber 15 through the communication port 14a as indicated by an arrow t3 while being stirred by the supply roller 18, and flows with the developing roller 12 by the supply roller 18 while flowing along the rotation of the supply roller 18 as indicated by an arrow t4. The contact portion 18a rubs against the surface 12a of the developing roller 12, and the amount of adhesion to the surface of the developing roller is regulated by the blade 19, so that the toner is applied from the developing roller surface 12a to the surface of the photosensitive member 5. The toner that has not been rubbed against the surface 12a of the developing roller 12 by the supply roller 18 flows along the rotation of the developing roller 12 as shown by an arrow t5, and further, the blade 19 as shown by arrows t6, t7 and t8. It circulates along the inner surface and the inner surface of the developing chamber. The remaining toner that has not been transferred to the photoconductor 5 among the toners adhered to the developing roller surface 12a is the sealing member 2
3 and returns into the developing chamber 15 and flows along the rotation direction of the developing roller 12 and the supply roller 18 as shown by arrows t10 and t11.

The developing device 10 (Y, C, M,
K) and toner cartridge 40 (Y, C, M, K)
As shown in FIG. 1, are arranged substantially radially around the photoreceptor 5 with different inverted angles.

If no measures are taken in such a developing device, if the image forming apparatus is installed so that the developing device is inclined with respect to the longitudinal direction of the developing roller, defective development may occur. Easier, or
As described above, there is a problem that the toner end is detected even though the toner remains in an unnecessarily large amount. Therefore, in this embodiment, the inner shape of the developing device 10 is configured so that the toner capacity on the side opposite to the side where the toner sensor 21 is provided with respect to the central portion C is reduced. More specifically, as shown in FIGS. 3 and 4, bulging portions 13b and 14b are formed on the first and second agitator chambers 13 and 14 on the side opposite to the side where the toner sensor 21 is provided. , The toner capacity on the opposite side is reduced.

Further, as described above, the plurality of developing devices 10
In the case where (Y, C, M, K) are arranged around the photoconductor 5 in different postures, if no measures are taken, the toner sensor 21 will not detect toner. At the time point, that is, when the toner remaining amount is reduced (toner end), the remaining toner amount greatly differs depending on the developing device. Therefore, in this embodiment, as shown in FIG.
The toner T (Y, C, M, T) in the developing device 10 at the time when the toner is no longer detected by the toner sensor 21
The internal shape of each developing device 10 (Y, C, M, K), that is, the toner is no longer detected, so that the remaining amount of K) is substantially the same in each developing device 10 (Y, C, M, K). At this point, the internal volume of the developing device 10 is changed according to the attitude of the developing device. More specifically, in this embodiment, the inner volume of the developing chamber 15 is substantially the same for each developing device, but the attitude angle of each developing device (the counterclockwise direction around the photoconductor 5 in FIG. 1 is positive). The larger the size of the developing device, the smaller the internal volume of the second agitator chamber 14 is. That is, the magnitude relationship of the internal volumes of the second agitator chambers 14 (Y, C, M, K) of each developing device is 1
4Y <14C <14M <14K.

The internal shape of each developing unit 14 is configured such that the remaining amount of toner at the time when the toner is no longer detected by the toner sensor 21 is larger than the remaining amount at which toner deterioration is accelerated. For example, if the deterioration acceleration point of the toner occurs when the remaining amount is about 60 to 80 g, the toner is not detected when the remaining amount is about 100 g.

Further, the toner supply from the toner cartridge 40 to the developing device 10 is performed even after the toner is detected by the toner sensor 21. More specifically, when the toner is no longer detected by the toner sensor 21, a display of a toner end is displayed on a display unit (not shown) of the image forming apparatus main body (for example, the toner cartridge 40Y is replaced because the remaining amount of yellow toner is low). When the user replaces the toner cartridge 40 and closes the cover of the image forming apparatus based on the message, at least the toner cartridge 40 is displayed.
(Y) Agitator 43 and First Unit of Developing Unit 10 (Y)
When the agitator 16 rotates and toner is supplied from the toner cartridge 40 to the developing device 10, and the toner sensor 21 detects toner, the display of the toner end disappears. However, after that, the agitator continues to rotate. Toner supply.

According to the developing device described above, the following operation and effect can be obtained. (A) The case 11 includes a case 11, a developing roller 12 rotatably provided with respect to the case 11, and a toner sensor 21 for detecting a remaining amount of the toner accommodated in the case 11. In the developing device provided in the case 11 at a position deviated from the central portion C in the longitudinal direction of the developing roller 12 and also deviated from the central portion in the height direction, the internal shape of the developing device 10 is Regarding the central portion C in the longitudinal direction, the toner sensor 2
1 is provided on the side opposite to the side on which the developing device 1 is provided.
However, even if the developing roller 12 is inclined in the left or right direction (the direction of arrow A shown in FIG. 4) in the longitudinal direction of the developing roller 12, the difference in the remaining amount of toner at the time when the toner end is detected is smaller than that of the conventional one. Become smaller. Therefore, it is possible to reduce the degree of occurrence of a situation in which the toner end is detected even though the toner remains in an unnecessarily large amount due to the difference in the inclination direction of the developing device 10 (when the developing device 10 is inclined to any direction). It is possible to do. Therefore, as a result, even when the developing device 10 is inclined leftward or rightward with respect to the longitudinal direction of the developing roller 12, it is possible to make it difficult for defective development to occur (that is, to set the range of inclination where no defective development occurs). Can be increased).

This will be described with reference to FIG. FIG. 5 is an exemplary conceptual diagram for explaining the function and effect of the present invention in comparison with the conceptual diagram 12 described above, wherein (a), (b), (c) and (d) are all developer units. 3 is a schematic cross-sectional view of the case 1 (corresponding to the case 11 of the above embodiment) viewed from the direction of its developing roller (corresponding to the developing roller 12 of the above embodiment). FIG. 7E is a plan view of FIG. 7A, and FIG. 7F is a side view of FIG. As shown in FIG. 1A, the toner sensor 2 (corresponding to the toner sensor 21 of the above embodiment) is provided at a position deviated leftward by 5 cm from the center C of the developing roller in the longitudinal direction (left-right direction in the figure). Have been. In the case 1, a bulging portion B is provided on the side opposite to the side where the toner sensor 2 is provided.
By forming the bulging portions 13b and 14b in the above embodiment, the toner capacity on the opposite side is reduced. FIG. 3A shows a case where the image forming apparatus, that is, the developing device (and thus the case 1) is installed horizontally with respect to the longitudinal direction of the developing roller (the left-right direction in the drawing), and FIG. (C) shows a case where the left side is inclined downward. As in the case shown in FIG. 12, for example, the width of the case 1 is 20 cm and the height (thickness) is 10 c.
m, the depth is 10 cm, the width of the bulging portion B is 8 cm,
Assuming that the height is 6 cm and the depth is 5 cm, the remaining amount of the toner T when the toner 2 is no longer detected by the sensor 2 in the case of FIG. ³ , the sensor 2 must be mounted 3.75 cm from the bottom 1 a of the case 1.
And 1.25 cm downward from the center in the height direction
The position is shifted.

Next, a description will be given by omitting the unit. As shown in FIG. 3B, the toner 2 is detected by the sensor 2 when the case 1 is inclined by about 38 ° so that the right side is downward.
Is no longer detected, the toner remaining amount is about 1135. Conversely, the toner remaining amount is about 490 when the case 1 is inclined by about 15 ° so that the left side is downward as shown in FIG. Becomes

In other words, in the example of FIG. 5, even if the developing device is inclined as shown in FIG. 5B, if the inclination is within about 38 °, no defective development occurs. c)
Even if the inclination is as shown in FIG. 7, if the inclination is within about 15 °, no defective development occurs. That is, in the case of the conventional device shown in FIG. 12, when it is inclined downward to the left as shown in FIG.
When the inclination exceeds about 15 ° (> 11 °), no defective development occurs, and in the conventional apparatus shown in FIG. b)
As shown in FIG. 5, when the angle is inclined downward to the right, development failure occurs when the angle exceeds about 30 °.
When the inclination is within about 38 ° (> 30 °), no defective development occurs. Further, regarding the remaining amount of toner, when the toner is inclined as shown in FIG. 12C, it is about 400 (the difference from the horizontal state is about 200) in the conventional apparatus shown in FIG. On the other hand, in the case of FIG. 5, the difference from the horizontal state is about 490 (about 110 (<20).
0)), and when tilted as shown in FIG. 12B, the conventional one shown in FIG. 12 was about 1150 (the difference from the horizontal state is about 550), whereas FIG. About 1135 (the difference from the horizontal state is about 535 (<55
0)). That is, in such a developing device, even when the developing device is inclined in the left or right direction in the longitudinal direction of the developing roller, the difference in the remaining amount of toner at the time when the toner end is detected becomes smaller than before. Further, in practice, it is difficult to imagine that the developing device (that is, the image forming apparatus) is installed at an angle of 38 ° by the user. Therefore, as shown in FIG.
Considering the inclination, the remaining amount of toner at the time of detecting the toner end is about 810 (the difference from the horizontal state is about 210), and the difference in the remaining amount of toner becomes smaller than before.

As can be seen from the above description, according to the developing device 10 of this embodiment, even when the developing roller 12 is inclined in the left or right direction in the longitudinal direction, the toner at the time when the toner end is detected is detected. Is smaller than before. Therefore, it is possible to reduce the degree of occurrence of a situation in which the toner end is detected even though the toner remains in an unnecessarily large amount due to the difference in the inclination direction of the developing device 10 (when the developing device 10 is inclined to any direction). It is possible to do. Therefore, as a result, even when the developing device 10 is inclined leftward or rightward with respect to the longitudinal direction of the developing roller 12, it is possible to make it difficult for defective development to occur (that is, to set the range of inclination where no defective development occurs). Can be increased).

(B) The inner shape of the developing device 10 is the case 1
By changing the shape of the inner wall 1 at the side where the toner sensor 21 is provided and the side opposite thereto with respect to the longitudinal center portion C, the toner capacity on the opposite side is reduced. Compared to the case where the shape of the agitator 16 and / or 17 is changed as described later, it is possible to easily configure the toner capacity on the opposite side to be reduced. Therefore, the degree of freedom of the shapes of the agitators 16 and 17 can be ensured.

(C) Since the toner cartridge 40 for replenishing toner is provided in the case 11 so as to be detachable, when the toner end is detected, the toner cartridge 40 is replaced so that new toner is put into the case 11. Can be replenished. Therefore, the toner remaining in the case at the time when the toner end is detected is not wasted. Also,
As compared with the case where the developing unit is replaced at the time of toner end, components of the developing unit 10 other than the toner cartridge are not wasted.

(D) Since the case 11 has a flat shape, if the image forming apparatus is to form a full-color image as shown in FIG.
(Y, C, M, K) can be easily arranged vertically. As described above, when the case 11 has a flat shape, the above-described problem is likely to occur. However, according to the developing device 10 of this embodiment, the inner shape is Since the toner capacity on the side opposite to the side on which the toner sensor 21 is provided is reduced, the development by the inclination in the longitudinal direction of the developing roller 12 is performed even though the case 11 has a flat shape. This makes it difficult for defects to occur, and prevents the detection of toner end even though toner remains in an unnecessarily large amount. That is, the inner shape of the developing device 10 is related to the central portion C,
The configuration in which the toner capacity on the side opposite to the side where the toner sensor 21 is provided is reduced is particularly effective when the case has a flat shape.

(E) Since the toner is supplied from the toner cartridge 40 to the case 11 even after the toner is detected by the toner sensor 21, the toner is not detected by the toner sensor 21 immediately after the cartridge is replaced. The situation is prevented.

(F) Developing roller 1 in each developing unit 10
2 a toner supply port 10a located far away from
A toner sensor 21 for detecting the presence or absence of toner is provided near the developing device 10 and the remaining amount of toner in the developing device 10 at the time when the toner sensor 21 stops detecting toner (see FIG. 1). (Y, C, M, K)
, Each developing device 10 (Y, C,
Since the internal shape of (M, K) is changed according to the attitude of the developing device, the following operation and effect can be further obtained. That is, (f1) the toner sensor 21 is connected to the toner replenishing port 1 located at a position far away from the developing roller 12 in the developing device.
Since it is provided near 0a, it is possible to prevent the toner remaining amount in the developing device 10 from being too small when the toner remaining amount is detected to be small. Therefore, when the developing device 10 is inclined in the longitudinal direction of the developing roller 12, the range of the inclination angle at which the developing failure does not occur is further increased. Further, the toner sensor 21
Is provided near the toner supply port 10a located far from the developing roller 12 for all the developing devices 10 (Y, C, M, K).
At 0, a difference in the toner pressure on the toner sensor 21 hardly occurs. Therefore, accurate detection is possible.
In addition, since the toner sensor 21 is provided near the toner supply port 10a, the toner sensor 21 receives the relatively fresh toner in a smooth state supplied from the toner cartridge 40 through the toner supply port 10a. They come into contact with each other (see arrows t1 and t1a in FIG. 3). Therefore, the possibility that toner adheres to the surface of the toner sensor 21 due to toner packing or the like is reduced, and as a result, erroneous detection hardly occurs. (F2) A point in time when toner is no longer detected by the toner sensor 21 even though the toner sensor 21 is provided near the toner supply port 10a of the developing device 10 that is located far away from the developing roller 12. The remaining amount of toner in the developing device 10 at each of the developing devices 10 (Y,
C, M, K) so that each developing device 1
0 is changed in accordance with the attitude of the developing device, the remaining amount of toner in the developing device 10 at the time when the toner is no longer detected by the toner sensor 21 is determined by each developing device 10 (Y, C, M, K) are almost the same.
Therefore, despite having a plurality of developing devices 10 having different postures, After the toner cartridge 40 is replaced after the detection, there is no large difference in the total amount of toner in the developing device 10 and the toner cartridge 40, that is, the total weight of the developing device 10 and the toner cartridge 40. Therefore, when the plurality of developing devices 10 are configured to be movable, and when the development target is selectively developed by the selective movement thereof, the movement operation of each of the developing devices 10 with respect to the development target (for example, the contact / separation operation). A large difference does not occur in the driving load required for the image processing, and a difference does not easily occur in the movement operation timing of each of the developing units 10 (Y, C, M, and K). As a result, a decrease in image quality is prevented. 2. After the above detection, when the toner cartridge 40 is replaced, there is no large difference in the toner supply time from the cartridge 40 to the developing device 10, so that the user is not worried. (G) The internal shape of each developing device 10 is such that the toner remaining amount is
Since the toner is configured so as to be larger than the remaining amount at which the toner deterioration is accelerated, the following operation and effect can be further obtained. That is, the toner in the developing device 10 is
It deteriorates in the process of flowing while contacting the inner wall 2 of the developing unit 10 and the like. The toner remaining in the developing device 10 without being supplied to the object to be developed via the developing roller 10 continues to flow in the developing device 10 and deteriorates mainly in contact with the developing roller 12 in the process. Becomes Deterioration of the toner, that is, a change in the shape of the toner, embedding or peeling of the external additive, deteriorates the chargeability and fluidity of the toner. When the charging property is deteriorated, the adhesion to the developing roller 12 is reduced.
Toner scattering, toner leakage, deterioration of transfer efficiency (accordingly, increase of waste toner rate) and the like are likely to occur. Further, when the fluidity is deteriorated, the uniformity of adhesion to the developing roller 12 is impaired, so that the uniformity of image quality is easily impaired. When the toner amount in the developing device 10 falls below a certain amount, the deterioration speed of the toner is exponentially accelerated. On the other hand, according to the developing device of this embodiment, the remaining amount of toner in the developing device 10 when the toner is no longer detected by the toner sensor 21 is the remaining amount at which toner deterioration is accelerated (the above-mentioned fixed amount). Since the internal shape of each developing device 10 is configured so as to be larger than the predetermined amount, the toner cartridge 40 is replaced and new toner is supplied before the remaining amount of toner in the developing device 10 falls below the predetermined amount. The Rukoto. As a result, the new toner is mixed with the toner remaining in the developing device 10, and the amount of toner in the developing device 10 exceeds the predetermined amount. As a result, according to this developing device, The remarkable deterioration of the toner in the developing device 10 is prevented. Therefore, scattering of toner, leakage of toner, deterioration of transfer efficiency (accordingly, increase of waste toner rate) and the like are less likely to occur, and uniformity of adhesion to the developing roller 12 is also maintained, so that uniformity of image quality is also maintained. The Rukoto.

<Second Embodiment> FIG. 6 is a schematic front sectional view showing a second embodiment of the developing device (or developing device) according to the present invention. In the figure, the same or corresponding parts as those in the first embodiment (FIGS. 1 and 2) are denoted by the same reference numerals or the same reference numerals with "". This embodiment is different from the first embodiment in that the inner shape of the developing device 10 has the shape of the agitator 16 'and / or 17' and the central portion C, and a toner sensor is provided. By changing between the present side and the opposite side, the toner capacity on the opposite side is reduced, and the other points remain the same.
For example, as shown in FIG. 7, the outer diameter of the shaft 16a, 17a of the first and / or second agitator 16 ', 17' is
By increasing the thickness on the side opposite to the side on which the toner sensor 21 is provided, the inner shape of the developing device 10 can be changed between the side on which the toner sensor is provided and the opposite side with respect to the central portion C. . The thickened portion is indicated by reference numeral 16a1 (17a1). By changing the shape of the agitator between the side where the toner sensor 21 is provided (the right side in the figure) and the opposite side (the left side in the figure) with respect to the central portion C, the toner in the developing device on the opposite side is changed. If the capacity is reduced, it is possible to make the inner wall shape of the case 11 common. Further, when the inner wall shape of the case 11 is changed as in the first embodiment in the case where a plurality of agitators 16 and 17 are provided, the toner may not be smoothly transported by the agitators 16 and 17. . For example, as shown in FIG. 8, the first and second agitator chambers 13,
14 is reduced on the side opposite to the side where the toner sensor 21 is provided, so that the toner capacity on the opposite side is reduced.
As can be seen from the rotation trajectories of the agitators 16 and 17, an area where the agitator and the toner do not contact each other is formed on the opposite side, and the toner is not smoothly transported by the agitators 16 and 17. 1
There is a possibility that the toner (T1) may stay between the agitator chamber 13 and the second agitator chamber 14, or between the second agitator chamber 14 and the developing chamber 15. On the other hand, when the toner capacity on the opposite side is reduced by changing the shape of the agitator as in this embodiment (see FIGS. 6 and 7), such a fear is eliminated. .

<Another Embodiment of Developing Apparatus> This embodiment is another embodiment of the developing apparatus.
As described above, a plurality of developing devices in which the toner sensor 21 is provided in the case 11 in a position deviated from the central portion C in the longitudinal direction of the developing roller 12 and also deviated from the central portion in the height direction are provided. The developing devices 10Y and 10C are provided with different inverted angles, and have relatively large inverted angles.
Regarding (see FIG. 1), the inner wall shape of the case 11 is changed as shown in FIG.
For example, as shown in FIG. 4, with respect to the central portion C, by changing between the side where the toner sensor 21 is provided and the opposite side, the toner capacity on the opposite side is reduced, and the inverted angle is set. Is relatively small developing unit 1
For 0M and 10K (see FIG. 1), for example, as shown in FIGS. 6 and 7, the shape of the agitators 16 and 17 is changed with respect to the central portion C on the side where the toner sensor 21 is provided and on the opposite side. Thus, the toner capacity on the opposite side is reduced.

With this configuration, the following operation and effect can be obtained. That is, for the developing devices 10Y and 10C having a relatively large inverted angle, the inner wall shape of the case 11 is changed between the side where the toner sensor 21 is provided and the opposite side with respect to the central portion C in the longitudinal direction.
Since the configuration is such that the toner capacity on the opposite side is reduced, it is possible to easily reduce the toner capacity on the opposite side as compared with the case where the shapes of the agitators 16 and 17 are changed. The degree of freedom of the agitator shape can be ensured. As described above, when the developing device has a plurality of agitators and the inner wall shape of the case 11 is changed, the toner may not be smoothly transported by the agitator as described above. A developing device 10Y in which the shape of the inner wall of the case 11 is changed in the developing device;
Since the developing device 10C has a relatively large inverted angle, even when the inner wall shape of the case 11 is changed, the toner is smoothly transported with the help of the free fall. That is, as shown in FIG. 9, for example, even if the toner T1 is stuck between the first agitator chamber 13 and the second agitator chamber 14, or between the second agitator chamber 14 and the developing chamber 15, T1 moves smoothly to the second agitator chamber 14 or the developing chamber 15 with the help of free fall.

On the other hand, the developing device 10 having a relatively small inverted angle
For M and 10K, for example, as shown in FIGS. 6 and 7, the shape of the agitators 16 and 17 is changed with respect to the central portion C between the side where the toner sensor 21 is provided and the opposite side. Since the configuration is such that the toner capacity on the opposite side is reduced, it is possible to make the inner wall shape of the case 11 common. In addition, the toner is smoothly transported.

<Third Embodiment> FIG. 10 is an essential part of an image forming apparatus using a developing device (or developing device) according to a third embodiment of the present invention, which is different from that of FIG. FIG. In the figure, the same or corresponding parts as those in the first embodiment (FIGS. 1 and 2) are denoted by the same reference numerals or the same reference numerals with "". In this image forming apparatus, a photoreceptor carrying a latent image to be developed is constituted by a photoreceptor belt 6 stretched over a roller 6a. Developing units 10 '(Y, C, M, K) having a shape are arranged in the same posture in the vertical direction. As in the first embodiment, the toner sensor 21 is disposed inside the case 11 'in the longitudinal direction of the developing roller 12 (the direction perpendicular to the plane of FIG. 6).
Is provided at a position deviated from the central portion C in the longitudinal direction and also deviated from the central portion in the height direction, and the inner shape of the developing device 10 ′ is provided with the toner sensor 21 with respect to the central portion C in the longitudinal direction. It is configured such that the toner capacity on the side opposite to the side on which the toner is supplied is reduced. Therefore, also in this embodiment, the effects (a), (b), (c), (d), and (e) obtained by the first embodiment can be obtained. Further, although the attitudes of the developing units are not different, the same effects as (f1), (f2), and (h) can be obtained. Further, when the configuration is the same as that of the second embodiment, the same operation and effect as those of the second embodiment can be obtained.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be appropriately modified within the scope of the present invention. For example, the shape (size) of the bulging portion of the case 11 or the shape of the agitator is determined by the toner sensor 21.
Can be set as appropriate according to the amount of deviation and the amount of remaining toner at the time of toner end detection.

[0045]

According to any one of the first to fourth developing devices, the developing device in which the toner sensor is provided at a position deviated leftward or rightward from the center with respect to the longitudinal direction and the height direction of the developing roller is provided. Even if the developing roller is inclined with respect to the longitudinal direction, the degree of occurrence of a situation in which poor development is unlikely to occur and toner end is detected even though a large amount of toner remains is reduced. It becomes possible to reduce. Further, claim 2
According to the developing device described above, it is possible to easily configure so that the toner capacity on the opposite side is reduced,
Also, the degree of freedom of the agitator shape can be ensured. According to the developing device of the third aspect, the inner wall shape of the case can be made common, and the toner can be smoothly transported by the agitator. According to the developing device of the fourth aspect, when the image forming apparatus is to form a full-color image, it is possible to easily arrange a plurality of developing devices in the vertical direction, Development defects due to inclination in the longitudinal direction are less likely to occur irrespective of the inclination direction, and the degree of occurrence of a situation where toner end is detected even though toner remains in an unnecessarily large amount is reduced. It becomes possible. According to the developing device of the fifth aspect, the developing device is provided at a position where the toner sensor is deviated leftward or rightward from the central portion in the longitudinal direction of the developing roller and also deviated from the central portion in the height direction of the case. Is inclined with respect to the longitudinal direction of the developing roller,
It is possible to reduce the degree of occurrence of a situation in which poor development is unlikely to occur and toner end is detected even though toner remains in an unnecessarily large amount. Furthermore, a developing device having a relatively large inverted angle can be configured so that the toner capacity on the opposite side can be easily reduced as compared with a case where the shape of the agitator is changed, and the degree of freedom of the shape of the agitator can be secured. As for the developing device having a relatively small angle of inversion, the shape of the inner wall of the case can be made common, and the toner can be transported smoothly.

[0046]

[Brief description of the drawings]

FIG. 1 is a schematic front sectional view showing a main part of an example of an image forming apparatus using a developing device according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is a partially omitted plan view of the developing device 10.

FIG. 4 is a partially omitted perspective view of the developing device 10.

5 (a), 5 (b), 5 (c) and 5 (d) are conceptual views for explaining the operation, FIG. 5 (e) is a plan view of FIG. 5 (a), and FIG. 5 (f) is a side view of FIG.

FIG. 6 is a schematic front sectional view showing a second embodiment of the developing device according to the present invention.

FIG. 7 is a sectional view of a shaft of the agitator.

FIG. 8 is an explanatory diagram of the same operation.

FIG. 9 is a front sectional view showing an example of a developing device in the embodiment of the developing device.

FIG. 10 is a schematic front sectional view showing a main part of an example different from that of FIG. 1 of an image forming apparatus or a developing device using a third embodiment of the developing device according to the present invention.

11 (a), (b) and (c) are conceptual diagrams for explaining a problem, (e) is a plan view of FIG. (A), and (f) is a diagram (e)
Side view.

12 (a), (b), (c), and (d) are conceptual diagrams for explaining a problem, (e) is a plan view of FIG. (A), and (f) is a side view of FIG.

FIG. 13 is an explanatory diagram of an example of a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Developing device 11 Case 12 Developing roller 16, 17 Agitator C Central part 21 Toner sensor 40 Toner cartridge

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H030 AA06 BB23 BB36 2H077 AA02 AA34 AB03 AB14 AB18 AD06 AD17 AD23 BA08 BA10 DA15 DA42 GA12

Claims (5)

[Claims] An image forming apparatus includes: a case; a developing roller rotatably provided with respect to the case; and a toner sensor for detecting a remaining amount of toner contained in the case. In the developing device provided at a position deviated from the central portion with respect to the longitudinal direction and the height direction of the developing roller, the internal shape of the developing device is such that the toner sensor is provided with respect to the longitudinal central portion. A developing device configured to reduce a toner capacity on a side opposite to the developing device. 2. The internal shape of the case is such that the shape of the inner wall of the case is changed between the side where the toner sensor is provided and the opposite side with respect to the central portion in the longitudinal direction, so that the toner capacity on the opposite side is reduced. The developing device according to claim 1, wherein the developing device is configured to: 3. An agitator for agitating the toner is provided in the case, and the internal shape is such that the shape of the agitator is the same as that of the central portion in the longitudinal direction and the side opposite to the side where the toner sensor is provided. 2. The developing device according to claim 1, wherein the toner amount on the opposite side is reduced by changing the toner amount on the opposite side. 4. The developing device according to claim 1, wherein said case has a flat shape. 5. A case, a developing roller rotatably provided with respect to the case, a plurality of agitators for transporting toner contained in the case toward the developing roller, and a case contained in the case. A toner sensor that detects the remaining amount of toner that has been provided, wherein the toner sensor is provided in the case at a position deviated from the center in the longitudinal direction and the height direction of the developing roller, In a developing device having a plurality of inverted angles, a developing device having a relatively large inverted angle has an inner wall shape of a case of the developing device with respect to the central portion in the longitudinal direction, on the side where a toner sensor is provided. And the opposite side, the configuration is such that the toner capacity on the opposite side is reduced. By changing the shape of the agitator between the side where the toner sensor is provided and the opposite side with respect to the central portion in the longitudinal direction, the toner capacity on the opposite side is reduced. Developing device.