JPH03237476A - Developing device - Google Patents

Abstract

PURPOSE:To decrease waiting time of an operator and to improve operation efficiency by rotating an agitating means at a high speed and replenishing developer around a developing roll in a short time when there is a deficiency of the developer. CONSTITUTION:This device is provided with a developing roll 12 which feeds toner T to a photosensitive body drum 1, a rubber blade 13, one edge of which is in sliding contact with a developing roll 12 and restricts the thickness of the toner T around the developing roll 12, and a residue toner detection means 16, which detects how much toner T is inside the developing part 10 by detecting electrostatic capacity between the developing roll 12 and blade 13, etc. Then, when it is detected that there is a developer deficiency around the developing roll of the developing device by the developer residue detection means 16, the agitating means 22 and 23 are rotated at a higher speed than normal and the developer from the inside is quickly fed to around the developing roll. Thus, even when there is deficiency of developer around the developing roll, this can be replenished in a short time, and the operating efficiency of the operator can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a developing device for an image forming apparatus such as a copying machine or a laser beam printer that employs an electrophotographic method.

(Prior art) In copying machines and the like, it is necessary to supply a developer (toner) to a latent image formed on an image carrier and to visualize this latent image as a toner image. This is done by a developing device.

A process cartridge equipped with such a developing device will be described with reference to FIG. 1. In cA, 1 is a photosensitive tram which is an image bearing member, and around the photosensitive tram 1 are a developing device 2, a charging roller 3. A cleaning device 4 is provided, which is integrally incorporated into a cartridge container 5a to form a process cartridge 5 which is freely disposed within the main body of the image forming apparatus.

The developing section 212 has a developing roller 12 facing the photosensitive tram 1 with a certain gap therebetween, and a developing section IO that supplies toner T toward the photosensitive tram 1 via the developing roller 12;
The toner T is held inside, and the toner T is stirred by the stirring member 22.
Developer storage for supplying developer to the developing section 10 via 23? 820
A is made from etc. When using this developing device 2, after peeling off the sheet member 15 of the opening 14 provided between the developing section 10 and the developer storage section 20, the stirring members 22 and 23 are rotated. It is necessary to first supply the toner particles in 20 to the developing roller 12 of the developing section 1o.

Here, a developer detection member 16 is installed in the developing section 1O, and when there is a shortage of toner T in the developing section 1O of the developing device 2, a message indicating that there is no toner is displayed on the panel of the main body of the device. .

(Problem to be Solved by the Invention) However, immediately after installing a new process cartridge 5 into the apparatus main body and peeling off the seal member 15 of the developing device 2, there is no toner T around the developing roller 12.
Until the toner T in the developer storage section 2o is sufficiently supplied into the developing section 10 by the agitating members 22 and 23, is there a display indicating that there is no toner on the panel of the apparatus main body, and during this time the operator cannot work and has to keep waiting? Yes, there was a problem with work efficiency.

Further, even in normal operation, if the amount of toner T consumed by the developing roller 12 is large, there is a problem in that the stirring members 22 and 23 cannot replenish the toner T to the developing roller 12 in time.

The present invention has been made in view of the above-mentioned problems, and its purpose is to detect a lack of developer around the developing roller by means for detecting the amount of remaining developer. To provide a developing device that can supply developer as quickly as possible and improve work efficiency.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an internal developer that is supplied to the developing roller by an agitating means that rotates in a fixed direction, and a developer remaining amount detecting means that supplies the internal developer toward the developing roller. In a developing device in which the presence or absence of developer around the developing roller is detected, when the developer remaining amount detection means detects that there is insufficient developer around the developing roller, the stirring means rotates at a higher speed than usual. It is characterized by being

Further, in the present invention, the internal developer is supplied to the developing roller by the stirring means rotated in a constant direction, and the presence or absence of the developer around the developing roller is detected by the developer remaining amount detecting means, In addition, in a developing device that is incorporated into a process cartridge and is attached to and detached from the main body of an image forming apparatus, at the same time as the process cartridge is attached to the main body of the apparatus, the remaining amount of developer detecting means detects whether there is insufficient developer around the developing roller. If it is detected that the stirring means is present, the stirring means is rotated at a higher speed than usual.

(Function) In the uninvention, when it is detected that there is insufficient developer around the developing roller of the developing device by the developer remaining amount detection means, the stirring means is rotated at a higher speed than usual to remove the developer inside. Since the developer can be quickly supplied around the developing roller, even if there is a shortage of developer around the developing roller, it can be replenished in a short time, thereby improving the work efficiency of one worker.

Further, in the present invention, when the developer remaining amount detecting means detects that the developer is insufficient around the developing roller of the developing device in the process cartridge at the time when the process cartridge is installed in the apparatus main body, When a new process cartridge is installed in the equipment main body (because the agitation means is rotated at a higher speed than usual, the waiting time for the installation of a new process cartridge to start work is significantly shortened, and the operator's work time is reduced). Efficiency can be improved.

(Example) Embodiments of the present invention will be described below based on the accompanying drawings.

First, a first example of the last complete column will be explained with reference to FIGS. t51 to 5.

First, the overall structure of the process cartridge will be described with reference to FIG. 1. Reference numeral 1 in FIG. 1 denotes a photosensitive tram, which is an image carrier, and is rotated in the direction of the arrow in the figure. This photosensitive tram
Around the developing section 2!2. A charging roller 3 and a cleaning device 4 are disposed, and these are assembled in a cartridge container 5a, and are disposed as a process cartridge 5 to be detachably attached to the main body of the image forming apparatus. Is this process cartridge 5 a developing device? Developer (toner) Tf in device 1! This is to facilitate maintenance by replacing the entire process cartridge 5 when an individual internal device reaches the end of its lifespan, such as when it is consumed. Note that 6 is a tram cover for protecting the photosensitive drum 1, which is opened and closed when the process cartridge 5 is attached to and removed from the main body of the apparatus.

That is, the photosensitive tram 1 is uniformly charged by the charging roller 3.
When only the image light is exposed and an electrostatic latent image is formed on the photosensitive drum l, the electrostatic latent image is directed toward the developing section W2 as the photosensitive drum 1 rotates, and is developed by the developing section a2. Toner T is supplied and converted into a toner image. The toner image is transferred onto a transfer paper via a transfer charger or transfer roller (not shown) on the device main body side, and this transfer paper carrying the toner image is sent to a fixing device, where the toner image is fixed as a permanent image. be done. Further, the photosensitive tram 1 after the transfer is cleaned of residual toner through a cleaning blade 4a of a cleaning device 4 that rubs against the outer surface of the photosensitive tram 1, and is prepared for primary image formation.

The developing device 2 is disposed on the side of the photosensitive tram l, and includes a developing section IO that supplies toner particles to the photosensitive tram l.

The developer storage section 20 is provided adjacent to the developing section 10, and includes a developer storage section 20 that holds toner T therein and supplies the toner T toward the developing section 10.

The developing unit body 10 of the developing unit 10 is rotated with a certain gap between it and the photosensitive drum 1, and the toner T is magnetically held on the outer circumference by the action of an internal magnet or the like. A developing roller 12 that supplies the toner toward the photosensitive drum L, a rubber blade 13 that rubs against the developing roller 12 at one end and regulates the thickness of the toner T around the developing roller 12 to be constant, and the developing roller 12. By detecting the capacitance between
A remaining toner amount detection means 16 or the like is provided to detect how much toner T is present in the developing section IO.

The developer storage section 20 has a rotating shaft 22 in its storage body 21.
a, 23a; two first and second stirring members 22 and 23 provided parallel to the axial direction of the photosensitive drum l and the developing roller 12;
The first one is provided. The toner T in the storage main body 21 is supplied through the second stirring member 22 and 23 into the developing section main body 1 of the developing section IO through the opening 14 between the developer storage section 20 and the developing section 10. .

Here, in the case of a new process cartridge 5, a sealing member 15 is attached to the developer storage section 20 and the opening 14 of the developing blade, so that when the process cartridge 5 is carried, etc., the toner inside the developer storage section 20 is removed. T leaks toward the developing section 10.

This prevents the toner T from flowing out.

Therefore, after installing the process cartridge 5 into the apparatus main body, it is necessary to peel off the seal member 15.

Next, a method of driving the first and second stirring members 22 and 23 will be explained with reference to FIG.

FIG. 2(b) shows a normal rotational force transmission state to the first and second stirring members 22, 23, in which the drum gear 30 provided at one end of the photosensitive drum l is connected to the large and small gears in the axial direction. 31
The large gear 31a of the first stepped gear 31 having the gears a and 31b meshes with the large gear 31a, and the small gear 31b of the first stepped gear 31b meshes with the first gear 32 for rotating the rotating shaft 22a of the first stirring member 22. Further, a second gear 33 for rotating the rotating shaft 23a of the second stirring member 23 is rotated from the first gear 32 via a fluid drag gear 34. That is, in normal image forming operations, when the photosensitive tram is rotated by a drive source of the apparatus main body (not shown), the first and second gears 32, 33 are also rotated through the first stepped gear 31, idler gear 34, etc. rotated and the first. Second stirring member 22.2
3, and the toner T in the developer storage section 20 is supplied toward the developing section 10.

Here, a new process cartridge 5, that is, a developing section W
When 12 is new, there is no toner T in the developing section 10 of the developing device 2, so when this process cartridge 5 is installed in the main body of the device.

1st. The second stirring members 22 and 23 rotate sufficiently, and the toner T in the developer storage section 20 is transferred to the developing roller 12 of the developing section IO.
You may need to wait until there are enough supplies nearby. but,
Since such waiting time reduces the work efficiency of workers, it is necessary to shorten it as much as possible.

In addition, even in the normal operating state, first and second stirring members 22 are provided in the developing section 10 of the developing device 2, which rotate at a constant speed (in this embodiment, it is 20 mm, hereinafter referred to as low speed).
．． Since the toner T in the developer storage unit 20 is supplied in a fixed amount by 23, 1. For example, when forming an image on a document with a high image density (a large amount of toner T supplied), the amount of toner T consumed Because the amount increases, developer storage section 2
A problem arises in that the toner T is not supplied from 0 to the developing section 10 in time, and even in such a case, the operator has to wait time and the work efficiency of the operator is lowered.

Therefore, in the present invention, when a new developing device 2 (new process cartridge 5) is installed in the main body of the device, or when the amount of toner T consumed during normal operation is large, the first
．． By increasing the rotational speed of the second stirring members 22 and 23 to a high speed (50 rpm in the case of this embodiment), one or more of the problems can be addressed and IE can be prevented due to low work efficiency. Note that the first and second stirring members 22 and 23 may be rotated at high speed all the time.

In this case, since the toner T deteriorates, the first and second stirring members 2
It is necessary to keep the high speed rotation time of 2.23 to a minimum.

The means for rotating the first and second gears 32, 33 at high speed will be explained below with reference to FIGS. 2(a) and 2(b).

In addition to the first stepped gear 31, the tram gear 30 of the photosensitive drum l includes a second stepped gear 3 consisting of large and small gears 35a and 35b.
It is possible to mesh with the large gear 35a of No. 5, and the small gear 35b can mesh with the first gear 32. The rotating shafts of the first and second stepped gears 31 and 35 are pivotally supported by a V-shaped joint par 36 that is rotated by an actuator 37. The second stage gear 35, which is normally separated from the tram gear 30 and first gear 32, can be brought together with the first gear 32 and drum gear 30 by rotation of the joint topper 36, as shown in FIG. 2(a). It becomes,
The first stepped gear 35, which is always in mesh with the drum gear 30 and the first gear 32, moves with its large gear 35a meshing on the drum gear 30 by the rotation of the joint topper 36.
The small gear 35b can be separated from the first gear 32. Also, the number of teeth of the large gears 31a and 35a of the 1ml, EfG two-stage gear 31°35 is approximately the same, but the number of teeth of the small gear 35b of the second-stage gear 35 is the same as that of the small gear 31b of the first-stage gear 31. The number of teeth is more than twice the number of teeth.

5. In the normal operating state, as shown in FIG. It is transmitted to the second gear 32°33,
When a new developing device 2 (new process cartridge 5) is installed in the main body of the apparatus, or when the amount of toner consumed by the developing section M2 is so large that toner T cannot be supplied to the developing section IO in time, in other words, toner remains. Amount detection means 16 or developing section 1
When a shortage of toner T is detected within 0, as shown in FIG. while rotating the small gear 31b away from the first gear 32, and move the large and small gears 35a and 35b of the second stepped gear 35 to the drum gear 3.
0 and the first gear 32.

Thus, the number of teeth of the second stepped gear 35 and the first stepped gear 31
From the relationship with the number of teeth, the second stage gear 35 is
In order to rotate the 2nd gear 32.33 at 2.5 times the speed (50 rpm), the 1st. The second WI stirring members 22 and 23 rotate in the same manner, and the toner T can be supplied to the developing section 10 in a short time. And remaining toner amount detection means 16
When it is detected that a sufficient amount of toner is being supplied into the developing section 10, the actuator 37 is activated again, returning to the state shown in FIG. 2(b) and returning to the normal operating state.

Furthermore, as described above, the actuator 37 and the joint bar 3
6. Simply use the tram gear 3 without using the second stage gear 31 etc.
Of course, the rotation speed may be 2.5 times the rotation speed of 0.

The above operation! To explain this with reference to FIG.
(For example, 10 seconds) If detected, the first and second stirring members 2
2.23 is shifted from normal low-speed rotation to high-speed rotation, and if the remaining toner amount detection means 16 detects a sufficient amount of toner T in the developing section 10, the first. The second stirring member 22,23 is returned to normal low speed rotation.

Now, the timing at which the first and second stirring members 22 and 23 are changed from low speed to high speed based on the detection of the toner T in the developing section 10 by the toner remaining amount detection means 16 will be further explained with reference to FIGS. 4 and 5. do.

FIG. 4 is a graph in which the output value of the detection signal of the remaining toner amount detection means 16 is shown on the vertical axis and the amount of toner in the developing section 10 is shown on the horizontal axis. The output value of the detection signal of the toner remaining amount detection means 16 is constant at 25V, and if there is only 10 g or less of toner T in the developing section 10.

The output value of the remaining toner amount detection means 16 becomes 5V and remains constant. When the amount of toner in the developing section IO becomes 20 g or less, the output value of the remaining toner amount detection means 16 decreases rapidly. 1st. Second stirring member 22
．． Is it necessary to rotate 23 at high speed?

Here, since the toner T in the developing section 10 is fluid,
Even if the remaining toner amount detection means 16 detects an output value of 10V, it does not necessarily mean that less than 20g of toner T is present in the developing section lo.
It cannot be said with certainty that there is no other option than the first one by the remaining toner amount detection means 16. The temporal change rate dV/dt of the output value of the remaining toner amount detector stage 16 was added as one of the criteria for determining when the second stirring member 22, 23 should be switched to high-speed rotation.

That is, as shown in FIG.
0 and a toner residual detection timer 41 are provided to reduce the amount of calculation +114
By inputting the output value from the remaining toner amount detection means 16 and the output value from the remaining toner detection timer 41, which is reset every 3 seconds, into 0, the remaining amount of toner before and after 3 seconds is determined by this calculation amount @40. The time rate of change dV/dt of the output value of the detection means 16 is calculated. When the output value of the remaining toner amount detection means 16 exceeds 5V and is below IOV, and when the time rate of change of the output average value dV/dt is less than a predetermined value, the arithmetic circuit 40 Second stirring member 2
2.23 is outputted a signal 42 to rotate at high speed, and vice versa, the 1st. A signal 43 for rotating the second stirring member 22° 23 at a low speed is output.

Therefore, for example, when the average value of the output value of the remaining toner amount detection means 16 is 8V, the time rate of change of the output value is 6.6V/5ec(
(from the predetermined value), the first and second stirring members 22.23
If the average value of the output of the remaining toner amount detecting means 16 is 25 V and the temporal change rate of the output value is dV/dt or approximately OV/sec, then the first
, the second stirring members 22, 23 are shifted to low speed rotation. In addition, when using a new process cartridge 5.

Since there is no toner T in the developing section 10, the average value of the output value of the remaining toner amount detection means 16 is 5V, and the temporal change rate dV/dt is also approximately OV/sec.
．． @2 Stirring members 22 and 23 are rotated at high speed.

In addition, as mentioned above, 1. When the second agitating member 22, 23 is rotating at high speed, it does not immediately issue a toner shortage signal on the panel on the main body side of the device, but instead issues a toner replenishment signal, and even after a certain period of high speed rotation, the toner shortage signal is not immediately output. If this occurs, a toner shortage signal will be sent to the panel.

Next, a second embodiment of the present invention will be described with reference to FIGS. 6 to 9. Components having the same functions as those in the first embodiment are designated by the same reference numerals, and their explanations will be omitted.

In this embodiment, only when a new process cartridge 5 is installed in the apparatus main body, the first . Second stirring means 22.
23 is rotated at high speed. That is, in addition to detecting the attachment of the process cartridge 5 to the main body of the apparatus, the remaining amount of toner is detected by either the first stage 16 or the developing section 10 of the developing device 2.
1. Only when a shortage of toner T is detected in 1. The second stirring members 22, 23 are rotated at high speed.

As shown in FIG. 6, a light emitting element 50 and a light receiving element 51 are mounted as the toner remaining amount detection means 16 so as to face the apparatus main body 100 side, and a developing device 2 is provided facing the light emitting element 5o and the light receiving element of the process cartridge 5. Condensing lenses 52 and 53 are attached to both sides of the developing section lO, and one light emitting element 5 is attached.
The light LA from o enters the developing section 10 through the condensing lens 52 and is guided from the condensing lens 53 to the light receiving element 51.

As shown in FIG. 7, when the process cartridge 5 is outside the main body of the apparatus, the light LA from the light emitting element 50 is
is diffused and only a small amount reaches the light receiving element 51, so it can be detected that the Proyas cartridge 5 is not installed in the main body of the apparatus (this is the condition 1 of No. 8 [2I), and the remaining toner amount detecting means 16 In addition, as shown in the sixth section, if a new process cartridge 5 is installed in the apparatus main body and the light LA from the light-emitting element 50 reaches the light-receiving element 51, then the developing state? Since there is no toner T in the developing section 10 of C222, the first and second stirring members 22 and 23 are rotated at high speed (condition 2 in FIG. 8, and the sensitivity of the remaining toner amount detection means 6) The light emitting element 5o
If the light LA does not reach the light receiving element 51, it is considered that there is sufficient toner T in the developing section 10 of the developing device 2, and the first and second stirring members 23 and 23 are rotated at low speed. (This is condition 3 in FIG. 8, and the sensitivity bell of the remaining toner amount detection means 16 is in the L position.

As described above, only when a new process cartridge 5 is installed in the apparatus main body, the first . Second stirring member 22.23
is rotated at high speed to reduce the waiting time when a new process cartridge 5 is installed in the installation main body. 1st. Second FIIl stirring means 22
．． 23 is not rotated at high speed, the waiting time of the operator does not change significantly. 0During normal operation, a certain amount of toner T is already in the developing section IO.

When the remaining toner amount detection means 16 detects a lack of toner,
If the worker stops the 1M rotation for a short period of time.

This is because the toner T can be sufficiently replenished into the developing section IO. Another advantage is that the high-speed rotation of the first and second stirring means 22, 23 can be reduced as much as possible, and deterioration of the toner T can be reduced.

Incidentally, as shown in condition 4 in FIG.
Of course, when it is detected that there is a shortage of toner T in the toner T, the first and second stirring means 22 and 23 can be rotated at high speed.

In addition, if the optical type as described above is not used as the remaining toner amount detection means 16, the process cartridge 5
As shown in FIG. 9, attachment to the device main body may be mechanically detected. In other words, a T-shaped switch member 54 is provided on the device main body side so as to be movable in the direction of the arrow, and this switch member is normally 54 is made to protrude outward via the spring member 55, but when the process cartridge 5 is attached to the apparatus main body, the switch member 54 is pushed into the apparatus main body against the elastic force of the spring member 55. The process cartridge 5 is installed in the apparatus main body by contacting the detection member 56 attached to the apparatus main body (effect of the invention).As is clear from the above explanation, there is a shortage of developer around the developing roller of the developing device Since the agitation means is rotated at high speed to replenish the developer around the developing roller in a short time when the developer is in a state where the developer is in the developing roller, the waiting time of the operator is reduced and the efficiency of one operation can be improved.

In addition, when the process cartridge 2 is installed in the main body, only when there is insufficient developer around the developing roller, the stirring member is rotated at high speed to replenish the developer around the developing roller in a short time. Even if this is done, work efficiency can be similarly improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a process cartridge on the right side of a developing device according to a first embodiment, and FIG. Second
A perspective view of the gear group for explaining the rotational drive of the stirring member, Fig. 3 is a timing chart for rotating the first and second stirring members of the developing device at high speed, and Fig. 4 shows the amount of toner in the developing section of the developing device. FIG. 5 is a graph showing the output of the toner detecting means, in which an arithmetic circuit calculates the temporal change rate of the average output value of the toner detecting means, and taking this value into account, the first and second stirring members are rotated at high speed. FIG. 6 is a control block diagram showing the process cartridge having the developing device according to the second embodiment installed in the main body of the apparatus and detecting the amount of toner around the developing roller, and FIG. 7 is the same diagram. FIG. 8 is a diagram showing the state in which the process cartridge is removed from the apparatus main body, and FIG. 8 shows the sensitivity level of the toner detection means and the first. FIG. 9 is an explanatory diagram of a detection means according to a modified embodiment for detecting whether or not the process cartridge is attached to the main body of the apparatus. 2...Developing device, 5...Process cartridge, 1
2...Developing roller, 16...Toner remaining amount detection means (
(Developer remaining amount detection means), 22.23... 1st degree second stirring member (stirring means)... Toner (developer). Figure 1 2υ Figure 2

Claims (4)

[Claims] (1) In a developing device in which the internal developer is supplied toward the developing roller by an agitating means that rotates in a fixed direction, and the presence or absence of developer around the developing roller is detected by a developer remaining amount detecting means. , when the developer remaining amount detection means detects that there is insufficient developer around the developing roller,
A developing device characterized in that the stirring means is rotated at a higher speed than usual. (2) The developing device according to claim 1, wherein the stirring means is rotated at a higher speed than usual when the output signal indicating developer shortage from the developer remaining amount detection means continues for a certain period of time. (3) When the developer remaining amount detection means outputs an output signal indicating a lack of developer and the time rate of change of this output signal value becomes less than a certain value, the stirring means is rotated at a higher speed than usual. The developing device according to claim 1, characterized in that: (4) The internal developer is supplied toward the developing roller by the agitation means that rotates in a constant direction, and the presence or absence of developer around the developing roller is detected by the developer remaining amount detection means, and the process cartridge In a developing device that is built into the image forming apparatus and is attached to and removed from the main body of the image forming apparatus, at the same time as the process cartridge is installed in the main body of the image forming apparatus, the remaining amount of developer detecting means detects that there is insufficient developer around the developing roller. A developing device characterized in that, when the stirring means is detected, the stirring means is rotated at a higher speed than usual.