JPH10177295A - Developer supplying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a true stop empty state by providing first and second blades rubbing the surface of a reflector and an opening part in the second blade, for illuminating the reflector. SOLUTION: The first and second blades 40 and 42 in a blade part 38 rub the surface of the reflector, together with the rotation of a stirring plate 34. The first blade 40 is shorter than the second blade 42, so that the first blade 40 rubs the reflector together with the rotation of a rotary shaft 30 and then, the second blade 42 rubs the surface of the reflector with a delay of a specified time, to brush away toner on the reflector and to prevent the sticking of the toner on the surface of the reflector. The toner remaining in a toner supplying chamber is detected in such a manner that light emitted from a light emitting member passes through the inner opening part 43 of the second blade 42 and reaches the reflector and the reflected light is detected by a light receiving member. At this time, the fact that the toner of the toner supplying chamber is reduced to a fixed level or below (stop empty state) is precisely detected and a user can be informed of the fact.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer replenishing device attached to a developing device in an image forming apparatus using a powder developer.

[0002]

2. Description of the Related Art In an image forming apparatus using a powder developer,
The remaining amount of the developer contained in the developer replenishing device must be detected, and when the remaining amount decreases, a warning must be issued to replenish the developer or replace the developer containing cartridge. For that purpose, conventionally, a container for storing the developer, a light emitting member for irradiating the container with light, and a reflection plate provided on the inner bottom of the container,
A light-receiving member for detecting light reflected by the reflector, a stirring and conveying plate attached to a rotating shaft arranged substantially horizontally, and a stirring and conveying plate fixed to the rotating shaft together with the stirring and conveying plate; Or after passing through the vicinity, having a blade member that rubs the surface of the reflection plate to remove the developer, and agitates the developer with the stirring and transporting plate, while the blade member passes from the reflection plate after the blade member passes. A developer replenishing device that detects reflected light to detect the remaining amount of developer has been proposed.

On the other hand, when the developer is replenished or the cartridge is replaced, a warning may be issued at a stage (stop empty state) where good image quality and normal function of the apparatus cannot be guaranteed if the remaining amount of the developer in the container further decreases. desirable. The reason is that if a warning is issued before the stage where the developer needs to be really replenished, while using the image forming apparatus, the consumer can still sufficiently form an image despite the warning. Recognition, the replenishment device is used beyond the state that really requires replenishment of the developer and replacement of the cartridge,
As a result, the image forming apparatus is damaged, and the inside of the image forming apparatus is significantly contaminated by the scattering of the developer.

[0004]

However, in the above developer replenishing device, the light receiving time of the light receiving member becomes proportionally longer as the remaining amount of toner decreases. This may be preferable to confirm the process of decreasing the remaining amount of toner,
In this case, the true stop empty state cannot be detected,
This is not always preferable from the viewpoint of accurately notifying the time when the supply of the developer and the replacement of the cartridge are necessary.

Accordingly, an object of the present invention is to provide a developer replenishing device capable of detecting a true stop empty state.

[0006]

In order to achieve this object, according to the present invention, in the developer supply device of the above-mentioned embodiment, the stirring / transporting plate passes through the vicinity of the reflecting plate in accordance with the rotation of the rotating shaft. A first blade that rubs the surface of the reflector after the first blade is longer than the first blade in the radial direction of the rotation axis and that the first blade rubs the reflector in accordance with the rotation of the rotation shaft. And a second blade for rubbing the surface of. Also,
The second blade is provided with an opening through which a developer can pass from the space between the first blade and the space downstream of the second blade in the rotation direction of the second blade, and illuminates the reflector through the opening. It is.

[0007]

According to this developer replenishing device, when the amount of the developer remaining in the container is equal to or more than a certain amount, the second blade remains along the container wall after the first blade passes. The developing agent is raked and transported onto the reflector. However, when the remaining amount of the developer decreases below the predetermined amount, the amount of the developer carried on the reflection plate by the second blade after the first blade has passed decreases sharply. Therefore, the light receiving time of the light receiving member changes significantly between the state in which the fixed amount of the developer is present in the container and the state in which the amount of the developer is less than that. Therefore, by setting the reflection plate at an appropriate level, it is possible to accurately detect the true stop empty state and notify the consumer of this.

[0008]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a developing device 12 used to visualize an electrostatic latent image formed on the outer peripheral surface of a photoreceptor 10 in an image forming apparatus such as a copying machine or a printer. The developer supply device according to the present invention is integrally incorporated. The developing device 12 may be a cartridge that is detachable from the image forming apparatus, or may be a device that is fixedly attached to the image forming apparatus.

The developing device 12 has a housing 14. The housing 14 accommodates a developing sleeve 16 facing the photoconductor 10. A toner supply chamber 18 is formed on the opposite side of the photoreceptor 10 across the developing sleeve 16. In the toner supply chamber 18, a supply roller 20 is provided.
A stirring member 22 is provided above the supply roller 20. A blade 24 having one end fixed to the ceiling of the housing 14 extends between the developing sleeve 16 and the stirring member 22, and a free end of the blade 24 is pressed against the outer peripheral surface of the developing sleeve 16. Toner supply chamber 18
Communicates with a toner supply chamber 28 via a passage 26,
The toner is supplied from the toner supply chamber 28 to the toner supply chamber 18.

A rotary shaft 3 is provided at a substantially central portion of the toner supply chamber 28.
0 is provided substantially horizontally, and a bracket 32 is fixed to the rotating shaft 30. 2, a stirring plate 34 is attached to the bracket 32 along its longitudinal direction (the direction parallel to the axis of the developing sleeve 16).
The stirring plate 34 is preferably made of a synthetic resin film or a metal film having a flat plate shape in a no-load state and having such a flexibility as to be able to bend in a curved shape when hitting an obstacle. The stirring plate 34 has a plurality of openings 36 formed at regular intervals in the longitudinal direction, and the toner can move through these openings 36.

The bracket 32 also has a wing 38 at one end.
It has. The blade portion 38 includes a first blade 40 having a rectangular shape extending from the bracket 32 and a second blade 42 having a rectangular frame shape surrounding the first blade 40. An opening 43 is formed. The first and second blades 40 and 42 are conveniently formed by cutting a single synthetic resin film or metal film having the same flexibility as the stirring plate 34. In addition, the wing portion 38
Is preferably arranged at a predetermined angle (eg, about 60 °) from the stirring plate 34 with respect to the direction opposite to the rotation direction of the rotating shaft 30. Further, it is preferable to attach a band-shaped elastic member 44 made of a foam material to the front side of the second blade 42 (that is, the surface on the upstream side in the rotation direction of the rotating shaft 30) along the free end. The first blade 40 does not have the same elastic member, but may have the same elastic member as the second blade 42.

A rotary shaft 30 is provided at the bottom of the toner supply chamber 28.
A horizontal step 46 slightly higher than other regions is formed in a region through which the blades 38 pass (i.e., one end side of the rotating shaft 30) in accordance with the rotation. Further, a reflection plate 48 is provided on the horizontal step portion 46, and the surface of the reflection plate 48 can be slidably contacted by the tips of the first blade 40 and the second blade 42. Note that a metal plate (stainless steel plate) or a mirror having a high reflectance and a high surface hardness is preferably used as the reflection plate 48. Further, the first blades 40 that rub against the reflecting plate 48 are for cleaning by removing the toner 50 from above the reflecting plate 48.
Is preferably set to a length that does not rub against the reflection plate 48.

An opening 52 is formed in the ceiling of the toner supply chamber 28 facing the reflection plate 48, and the opening 52 is formed of a light-transmitting window 5 made of a light-transmitting plastic or glass.
4 are provided. Outside the developing device 12 and above the light transmitting window 54, a light emitting member 56 capable of illuminating the reflecting plate 48 through the light transmitting window 54, and a light emitting member 56 emitted from the light emitting member 56 and An illumination device 60 integrally provided with a light receiving member 58 that receives the reflected light and outputs an electric signal based on the received light is provided. Lighting device 60
Is electrically connected to the toner remaining amount detecting device 62,
The remaining amount of toner in the toner supply chamber 28 is detected based on the output of the light receiving member 58.

In the developing device 12 configured as described above,
The developing sleeve 16, the supply roller 20, the stirring member 22, and the rotating shaft 30 are drivingly connected to a motor (not shown), and these members rotate in directions indicated by arrows based on the rotation of the motor. As a result, in the toner supply chamber 28, the stirring plate 34 rotates in the direction of the arrow,
8 is supplied to the toner supply chamber 18 via the passage 26.

In the toner supply chamber 18, the toner is stirred by the stirring member 22, and the toner stirred by the supply roller 20 is supplied to the developing sleeve 16. Then, the toner in contact with the outer peripheral surface of the developing sleeve 16 is conveyed in the sleeve rotation direction, and is held on the outer peripheral surface of the developing sleeve 16 in a region where the blade 24 is pressed against the developing sleeve 16.
Next, the toner that has passed through the blade pressure contact portion is
The electrostatic latent image on the photoreceptor 10 is brought into contact with the electrostatic latent image on the photoconductor 10 at a portion facing the developing sleeve 16 and is visualized.

During the developing operation, the first and second blades 42 of the blade portion 38 rub the surface of the reflecting plate 48 with the rotation of the stirring plate 34. At this time, since the first blade 40 is shorter than the second blade 42 as described above,
As shown in FIGS. 3A and 3B, the first blade 40 first rubs the reflecting plate 48 with the rotation of the rotating shaft 30, and then the second blade 42 reflects with a predetermined time delay. Board 4
8 is rubbed to remove the toner 50 on the reflection plate 48 to prevent the toner 50 from sticking to the surface of the reflection plate 48.

Next, detection of the remaining amount of toner in the toner supply chamber 28 will be described. When the remaining amount of toner in the toner supply chamber 28 is equal to or higher than a predetermined level, the light emitted from the light emitting member 56 of the lighting device 60 is not blocked by the toner and does not reach the reflecting plate 48. However, when the remaining amount of toner drops to a predetermined level, as shown in FIG. 3B, there is a gap between the first blade 40 and the second blade 42 that rubs the reflecting plate 48 with a delay. The state where the toner 50 does not exist on the reflection plate 48 is created, and the light emitted from the light emitting member 56 of the lighting device 60 passes through the inner opening 43 of the second blade 42 and reaches the reflection plate 48, and furthermore, The reflected light is received by the light receiving member 5 of the lighting device 60.
8 to be detected. Then, the light receiving member 58 creates a signal having a length corresponding to the light receiving time, and outputs the signal to the toner remaining amount detecting device 62. Then, the remaining toner detecting device 62 estimates the remaining toner from the length of the signal.

When the opening 36 is not formed in the stirring plate 34, the toner 50 is scooped by the stirring plate 34 as shown in FIG.
Is formed without any space 66. The toner supply chamber 28 is not scooped up by the stirring plate 34.
The toner 50 remaining in the rear portion collapses along the rear wall of the supply chamber and covers the reflection plate 48. The area where the toner 50 covers the reflection plate 48 is substantially proportional to the remaining amount of toner. For this reason, when the remaining amount of toner becomes equal to or less than a predetermined amount, a signal having a waveform length substantially proportional to the decrease of the remaining amount of toner is periodically generated by the light receiving member 58 as shown by white and black circles in the graph of FIG. (The white circles indicate measured values when the developing device was mounted at a proper position with respect to the illumination device, and the black circles indicate measured values when the developing device was displaced from the proper position by a predetermined distance. The predetermined distance is a value covering a range in which the lighting device varies in mounting.) Certainly, the proportional relationship between the remaining toner amount and the waveform length is preferable from the viewpoint of grasping the toner reduction process. However, as described in the section of the related art, it is necessary for the customer to replenish the toner. It is not always preferable from the viewpoint of accurately notifying the timing and the timing of replacement of the developing device (or toner cartridge).

On the other hand, in the above embodiment, since the stirring plate 34 is provided with the opening 36, the toner 50 may escape to the rear through the opening 36 when the stirring plate 34 moves. it can. Therefore, the toner surface after the stirring plate 34 has passed is leveled substantially horizontally, and the toner surface on the reflection plate 48 is also kept substantially horizontal. Therefore, even when the remaining amount of toner is small, the light of the light emitting member 56 does not reach the reflecting plate 48 because the reflecting plate 48 is always covered with the toner 50 until the toner 50 is present at a certain level or more. However, when the toner 50 falls below the certain level, light reaches the reflecting plate 48, and when the toner surface slightly lowers thereafter, many areas (surfaces) of the reflecting plate 48 are illuminated and light is received. The waveform of the signal generated by the member 58 becomes longer.

In a state where the remaining amount of toner is low,
The second blade 42 passing over the reflection plate 48 rakes the toner 50 remaining at the rear of the toner supply chamber 28 and carries the toner 50 onto the reflection plate 48. Then, in a state in which the toner is present at a certain level or more even when the remaining amount of toner is small, as shown in FIG. 3A, the second blade 42 carries a certain amount of toner 50 onto the reflection plate 48, but When the remaining amount of toner falls below a certain level, the amount of toner carried by the second blade 42 sharply decreases, and the waveform of a signal generated by the light receiving member 58 sharply increases.

More specifically, the relationship between the remaining amount of toner and the waveform length of a signal output from the light emitting member in the developing device of the above embodiment is shown by a white square and a black square in FIG. The squares are the measured values when the developing device is mounted at the proper position with respect to the illumination device, and the black squares are the measured values when the developing device is shifted from the proper position by a predetermined distance. Is the value that covers the range of variation in the mounting of the lighting device.) As is apparent from this graph, when a blade member having no opening as in the developing device of FIG. 4 is used, the output of the light receiving member 58 changes in proportion to the remaining amount of toner. In this case, it was confirmed that when the remaining amount of toner becomes equal to or less than a predetermined amount (about 110 g), the waveform length sharply increases. Further, it was confirmed that even if the setting of the developing device, that is, the optical axis with respect to the reflecting surface was shifted, it was possible to accurately detect that the toner amount in the toner supply chamber was reduced to a predetermined amount or less.

As described above, according to the developing device 12, the provision of the opening portion 36 in the stirring plate 34 allows the reflection plate 4
By providing the first blade 40 and the second blade 42 passing over the upper surface 8, it is clearly detected that the toner 50 in the toner supply chamber 28 has dropped below a predetermined level (that is, the state of stop empty). This can be notified to the consumer.

FIG. 6 shows the relationship between the radial length of the stirring plate 34, the pressure of the toner applied to the developing sleeve 16, and the toner surface level at the front wall position of the toner supply chamber 28. FIG. 7 shows a state in which the opening 3
The relationship between the distance up to 6 (indicated by reference numeral 68 in FIG. 2), the toner pressure applied to the developing sleeve 16 and the toner surface level at the position of the front wall of the toner supply chamber 28 is shown. From these graphs, for example, in order to prevent aggregation of the toner and ensure necessary toner transportability, for example, the stirring plate 3
It is considered preferable that the length of 4 is about 29 mm and the distance from the tip of the stirring plate to the opening is about 8 mm.

The stirring plate 34 is, as shown in FIG.
Slits 70 may be provided between adjacent openings 36 to divide the openings. In this case, when the stirring plate 34 rotates, the toner 50 flows out of the slit 70 to the rear of the stirring plate 34, and the toner surface becomes more horizontal.

Further, it is desirable to provide a space inside the developing device 12 where the stirring plate 34 can completely extend as shown in the figure. This is because if the agitating plate 34 is always in contact with the inner wall of the housing 14 and is bent, the original linearity and toner transportability are reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a developing device integrally provided with a replenishing device according to the present invention.

FIG. 2 is a perspective view of a stirring plate and a blade member.

FIG. 3 is a diagram illustrating the operation of first and second blades.

FIG. 4 is a cross-sectional view of a developing device having no opening in a stirring plate.

FIG. 5 is a graph showing a result of examining a relationship between a remaining amount of toner and a light receiving member output signal waveform length using the developing device shown in FIGS. 1 and 4;

FIG. 6 is a graph showing a relationship between a radial length of a stirring blade and a powder pressure (toner pressure) acting on a developing sleeve.

FIG. 7 is a graph showing the relationship between the distance between the tip of the stirring blade and the opening, the powder pressure acting on the developing sleeve, and the toner surface level at the front wall position of the toner supply chamber.

[Explanation of symbols]

12 developing device, 28 toner supply chamber, 30 rotating shaft,
34 stirring plate, 36 opening, 38 blade member, 40
First blade, 42 Second blade, 48 Reflector, 54
Window 56, light emitting member 58, light receiving member 62, toner remaining amount detecting device.

Claims (1)

[Claims] A container for storing a developer having a window through which light can enter, a light emitting member for irradiating the inside of the container with light through the window, and a reflector provided at an inner bottom of the container. A light-receiving member that receives light reflected by the reflection plate, and a stirring and conveying plate that rotates inside the container about a rotation axis disposed substantially horizontally, and stirs and conveys the developer contained in the container. In the developer replenishing apparatus provided with: a first blade that rubs the surface of the reflection plate after the stirring and conveying plate passes near the reflection plate according to the rotation of the rotation shaft; A second blade that is longer in the radial direction of the rotation axis than the first blade and rubs the surface of the reflection plate after the first blade rubs the reflection plate in accordance with the rotation of the rotation shaft; The developer passes from the space between the first blade and the downstream side in the rotation direction of the second blade. A developer replenishing device, characterized in that an opening through which the light can pass is provided, and the reflector is illuminated through the opening.