JPH0815984A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device where developer is uniformly supplied, which is rapidly set and in which density is not lowered when new developer is supplied. CONSTITUTION:Whether it is a copying mode or not is detected (step S1-1). When this mode is set, whether the device is in a special state where image forming operation is continued though the remaining quantity of toner in a hopper is small or not is judged(step S1-2). When the device is not in the special state, the toner is supplied according to a signal from a toner sensor after turning on for two seconds and turning off for one second because the specified quantity of toner exists in the hopper or the toner does not exist and the image forming operation is stopped(step S1-3). When the device is in the special state, the toner is supplied after turning on for two seconds and turning for ten seconds (step S1-4) to mix new and old toner little by little. When a set mode is selected, the hopper is consecutively driven for three minutes after starting the operation, and then the toner is supplied by turning on for two seconds and turning off for one second intermittently (step S1-5).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in the field of image forming technology such as electrophotographic copying machines and information recording devices, and in particular, a latent image formed on an electrostatic latent image carrier is visualized by a developer. The present invention relates to an image forming apparatus for realizing the same.

[0002]

2. Description of the Related Art As an example of a conventional developer replenishment system,
A method of intermittently replenishing the developer transporting section with a developer from a developer supply container provided at one end of the developer container in the longitudinal direction and supplying the developer in the longitudinal direction of the developer container is disclosed in Japanese Patent Application Laid-Open No. Hei 5 (1999) -54.
It is proposed in Japanese Patent Publication No.-265325.

In this system, it is disclosed that uniform developer replenishment is possible by adjusting the predetermined replenishment time and the predetermined rest time according to the environment and mechanical variations.

[0004]

However, in the above-mentioned conventional example, there is the following problem because an appropriate measure according to the state of the developing device which fluctuates depending on the state of the image forming device is not taken into consideration.

First, when a developing device is newly installed,
Normally, after the developer is supplied to the developer supply container, the developer setting mode set in the image forming apparatus is operated to supply the developer to the developing apparatus. Therefore, there is a problem that it takes too much time to install the developing device.

Secondly, when the developer in the developer supply container is used up, normally, a message prompting the user to replenish the developer is displayed. However, when there is no developer stock, the developer is not supplied. When the developer is replenished after the developer in the developer container has been consumed and the amount of developer in the developer container has decreased, the amount of new developer in the developer container is large. However, there is a problem that the image density is reduced and the background fog is generated.

The present invention solves the above problems and realizes uniform replenishment of the developer, enables rapid installation of the developing device, and lowers the image density even when replenishing a new developer. An object of the present invention is to provide an image forming apparatus that does not generate a background fog or the like.

[0008]

According to the present invention, the above object is to provide a developer container for containing a developer, a developer amount detecting means for detecting the amount of the developer in the developer container, and And a developer replenishment control means for replenishing the developer from the developer supply container to the developer conveying portion formed along the longitudinal direction of the developer container based on the output of the developer amount detecting means, and the inside of the developer conveying portion. In the image forming apparatus having a developer conveying means for dropping the developer into the developer container while conveying the developer in the longitudinal direction, the developer replenishment control means replenishes the developer for a predetermined time. , The supply is set to stop for a predetermined time, and the predetermined time to supply and the predetermined time to pause are set to be selected according to the operation mode and operation state of the image forming apparatus. Achievement It is.

[0009]

According to the present invention, the predetermined time required for replenishment of developer replenishment and the predetermined time required for suspension are selected according to the remaining amount of the developer in the developer container and the operating state of the image forming apparatus, For example, when there is no developer in the developer container and it is not necessary to immediately perform the image forming operation, after the continuous replenishment for a predetermined time with the predetermined time required for the pause being zero, the predetermined time required for the pause. Intermittent replenishment is performed at a predetermined ratio. This makes it possible to shorten the predetermined time required for replenishment while replenishing the developer uniformly in the longitudinal direction of the developer container. Also, despite the small amount of developer remaining,
When the image forming operation is being performed, the ratio of the predetermined time required for the pause is increased and the supply for the predetermined time is performed.
Old developer and new developer are mixed little by little,
Does not cause a decrease in density.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a flow chart showing a procedure for selecting a developer replenishing sequence in a first embodiment of the present invention, and FIG. 2 is a front view of a developing device, a developer supply container, and a developer transport unit to which the present invention is applicable. 3 is a side sectional view of FIG. 2, FIG. 4 is a view showing the shape of a developer falling control wall used in the developer transport section shown in FIGS. 2 and 3, and FIG. 5 is a timing of a drive signal of the hopper shown in FIG. FIG. 6 is a diagram showing a toner drop amount distribution when toner is replenished at the timing shown in FIG. 5 in the developing device shown in FIGS. 2 and 3, and FIG. 7 is a continuous drive of the hopper shown in FIG. FIG. 6 is a diagram showing a toner drop amount distribution in the case of a drop.

In the apparatus of this embodiment, as shown in FIG. 3, the hopper 20 as a developer supply container is driven according to the output signal of the toner sensor 11 as a developer amount detecting means provided in the developer container 10. Then, the toner serving as the developer is supplied from the hopper 20 to the developer transport unit 30. Then, the toner supplied to the developer transport unit 30 is transferred to the developer container 10 by the transport screw 31 which is a developer transport unit.
While being conveyed in the longitudinal direction, the developer is dropped and supplied to the developer container 10 along the developer falling amount control wall 32 as shown in FIGS.

FIG. 5 shows a timing chart of the signal of the toner sensor 11 and the drive signal of the hopper 20 at this time. In this embodiment, the normal supply is the hopper 20.
The driving time is set to 2 seconds, and the rest time (hereinafter, hopper OFF time) is set to 1 second. Therefore, the toner replenishment amount per time is always constant, and the toner drop amount distribution in the longitudinal direction of the developer container 10 becomes substantially uniform as shown in FIG.

However, it has been found that when the toner replenishment control as described above is always performed, inconvenience occurs depending on the operation mode of the image forming apparatus and the state of the apparatus. Therefore, a first embodiment of the present invention that solves the problem will be described with reference to FIG.

In the present embodiment, the toner replenishing sequence is roughly divided into two modes, that is, "normal copy mode" and "developer setting mode". First,
Which of these two modes is detected (step S1-1).

Then, when the normal copy mode is selected, it is judged whether or not it is in the "special state" (step S1-2). The special state is a state in which the image forming operation is continued even when the toner in the hopper 20 is exhausted in the normal copy mode. That is, when the toner runs out, in principle, the image forming operation is stopped and the user is urged to replenish the hopper 20 with toner. If the operation is completely prohibited, the device can be operated from the viewpoint of causing trouble to the user. In view of this, in this embodiment, the image formation of 500 sheets is permitted after the absence of toner in the hopper 20 is detected, and the special state is set until the image formation of 500 sheets is completed after the presence of toner in the hopper 20 is detected.

Therefore, when the toner is not in this special state, whether toner exists in the hopper 20 to some extent,
Alternatively, since the image forming operation is stopped even if the toner is not sufficiently present, the toner is replenished according to the signal from the toner sensor at the hopper ON time of 2 seconds and the OFF time of 1 second as shown in FIG. 5 (step S1- 3).

On the other hand, in the special state, the toner replenishment sequence is set to the hopper ON time of 2 seconds and the OFF time of 10 seconds (step S1-4). As a result, there was no decrease in image density, uneven density, fog, etc.

The reason for this is that after the toner in the hopper 20 is exhausted, the toner in the developer container 10 is consumed and the toner in the developer container 10 becomes less than a predetermined amount. Toner supply is hopper OFF
It is considered that since the time was extended, the durable toner and the new toner in the developer container 10 having different properties were mixed little by little.

Next, when the developer setting mode is selected, the hopper 20 is continuously driven for 3 minutes from the start of the mode, and thereafter, the developer container is intermittently replenished by the hopper ON time of 2 seconds and OFF time of 1 second. The process is continued until the toner is replenished in the toner 10 in a predetermined amount.

Here, the reason for using the above replenishment sequence in the developer installation mode will be described. The developer installation mode is performed when only the image forming apparatus or the developing apparatus is newly installed. In order to supply toner from the hopper 20 to the empty developer container 10 to enable image formation. Is the mode. Therefore, even if the toner drop amount distribution in the longitudinal direction of the developer container 10 is not uniform, there is no difference in the properties of the toner itself, so that problems such as image unevenness do not occur. Therefore, in this embodiment, when the amount of toner supplied from the hopper 20 is set to 60 g / min and the predetermined amount of toner in the developer container 10 is set to 300 g, the replenishment sequence as described above is executed to install the developer. The time required for the mode can be shortened by 6 minutes and 1.5 minutes as compared with 7.5 minutes in the conventional example.

Considering the case where the toner is replenished without the hopper OFF time until the end of the developer setting mode, the time required for the setting seems to be as short as 5 minutes, but in reality, the toner is continuously supplied. Since the toner drop amount distribution in the longitudinal direction in the case of performing is as shown in FIG. 7, the toner drop amount is large on the toner sensor 11 side and the developer container 10
There has been a problem that the toner sensor detects the presence of toner before the amount of toner therein reaches a predetermined amount. Therefore, the time when the continuous supply of toner is stopped depends on the toner sensor 11
Is set to be shorter than that for detecting the presence of toner, and intermittent replenishment is performed only for a period of time during which the toner amount distribution in the developer container 10 is made to some extent by the rotation of the toner stirring member 12 after the continuous replenishment is stopped. It is desirable to be told. On the contrary, when the toner drop amount on the toner sensor 11 side is small, the toner is replenished by a predetermined amount or more, and in the worst case, the toner may overflow from the container 10.

As described above, according to the present invention, the time required for installation is shortened as compared with the conventional one, and even when a new toner is replenished, the density reduction, the density unevenness, and the fog do not occur.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. The same parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

FIG. 8 is a flow chart showing the developer replenishing sequence in the second embodiment of the present invention, FIG. 9 is a view showing the hopper of this embodiment, and FIG. 10 is a view showing the fluctuation of the toner supply amount in this embodiment. FIG. 11 is a diagram showing the difference in the drop amount distribution with respect to the toner supply amount when the toner is intermittently supplied, and FIG. 12 is a diagram showing the toner drop amount distribution according to the toner supply sequence.

With the downsizing of the main body of the image forming apparatus and the increase of the capacity of the hopper, the supply port for supplying the toner from the hopper to the developer transporting section is inevitably provided at a position higher than the bottom of the hopper. .

FIG. 9 is a view showing such a hopper of this embodiment. The toner in the hopper 20 is fed in the directions of arrows b and c by the toner feeding screws 23 and 24 by the stirring member 22 rotating in the direction of arrow a, and is fed in the directions of arrows d and e by the toner feeding screw 25 to develop the toner. It is supplied to the agent transport section.

The absence of toner in the hopper 20 is detected by the toner sensor 26 in the hopper 20, such as a piezo element, and the detection level is no toner when the amount of toner in the hopper 20 reaches about 300 g. Is set. It is desirable that this amount be as small as possible so that the replenished toner does not overflow in a region where the toner supply amount from the hopper 20 is stable.

Below, based on the flowchart of FIG.
The toner supply sequence of this embodiment will be described.

First, the copy mode is detected (step S8-1), and in the normal copy mode, it is judged whether or not it is in the special state (step S8-2). The toner is replenished according to the signal from the toner sensor with the ON time of 2 seconds and the OFF time of 1 second (step S8-3). The special state is almost the same as that described in the first embodiment, but here, the image forming time is 20 after the absence of toner in the hopper 20 is detected.
It means until a lapse of minutes or until the toner is supplied to the hopper 20.

When a hopper of the type as in this embodiment is used, as can be seen from FIG. 10, the toner supply amount decreases when the toner amount falls below 300 g. In this state, the hopper ON time is 2 seconds and the OFF time is 1 When replenishment is performed in the second sequence, the toner drop amount distribution in the longitudinal direction of the developer container 10 also changes as shown in FIG.
When the amount of toner supplied from the printer decreases, it becomes difficult for the toner to drop toward the front side.

This is because the toner supply amount per unit time is reduced, so that the toner amount exceeding the height of the developer drop amount control wall on the front side is reduced and the toner is easily conveyed to the back side.

Therefore, in this embodiment, when it is determined that the toner is in a special state, the toner in the hopper 20 is 300 g.
It is detected whether or not there is the above (step S8-4), and if there is, the toner is replenished with the hopper ON time of 2 seconds and OFF time of 1 second (steps S8-4 to S
8-3) If the amount is less than 300 g, the amount of toner supplied from the hopper 20 is small, so the toner is supplied according to the signal from the toner sensor 11 with the hopper OFF time set to 0 seconds (step S8-5).

As a result, the toner drop amount distribution in the developer container 10 does not largely change, and the toner amount in the developer container 10 can be prevented from decreasing as compared with the first embodiment, so that the special state can be maintained for a long time. You can

In the first embodiment, after the absence of toner in the hopper 20 is detected, the image formation of 500 sheets is allowed without toner replenishment, but in the present embodiment, a copying machine of 50 c.pm for 20 minutes (= 1
No problems occurred even if the image formation of (000 sheets) was allowed.

After the toner is supplied to the hopper 20, the toner amount in the developer container 10 does not decrease from the predetermined amount even if the normal toner replenishing sequence is performed, and the toner is discharged from the discharge port after the toner is supplied. Since there is a time lag until the amount of the discharged toner reaches a steady state, there was no occurrence of image density unevenness or fog.

FIG. 11 shows the difference in the toner drop amount distribution due to the difference in the toner supply sequence. Even if the amount of toner supplied from the hopper reaches 40 g / min, depending on the sequence,
It can be seen that the distribution of the amount of fall is made uniform.

On the other hand, when the developer installation mode is selected, similar to the first embodiment, continuous replenishment is performed for a predetermined time (step S8-6), but the hopper as in this embodiment is used. When using a hopper 2 as shown in FIG.
The amount of toner supplied from the hopper 20 greatly changes with respect to the amount of toner in 0, and the path for conveying the toner to the toner supply port is long, so that the toner is supplied to the empty hopper 20 before the toner supply port. A time lag of about 1 minute is added from the time of discharge to 4 minutes of continuous replenishment.

As described above, according to the present invention, the time required for installation is shortened even when the supply port for supplying toner from the hopper to the developer conveying section is located at a position higher than the bottom of the hopper, and In addition, it is possible to prevent a decrease in density due to replenishment of new toner, and further to make the toner drop distribution uniform.

(Third Embodiment) Next, a third embodiment of the present invention will be described. Note that the description of the common points with the first embodiment is omitted.

In this embodiment, a sequence in which the toner-free detection level in the hopper 20 in the second embodiment is set to about 250 g so that a special state is not allowed and the hopper OFF time is set to 0 second only for one minute after the toner is supplied. To execute. As a result, it is possible to shorten the time lag in which the toner supply amount to the developer container 10 returns to the steady state even after the toner is supplied to the hopper 20.

The present invention is not limited to the above embodiment, and is characterized in that the toner supply sequence is selected according to the operation mode of the image forming apparatus or the state of the image forming apparatus. is there.

Further, in the above-mentioned embodiment, the control means such as CPU can be applied as the developer replenishment control means.

[0044]

As described above, according to the present invention,
Since the predetermined time required for developer replenishment and the predetermined time required for suspension are selected according to the operation mode and operation state of the image forming apparatus, image quality is improved regardless of the state of the developing apparatus or the developer supply container. It is possible to supply an appropriate developer without affecting the above.

[Brief description of drawings]

FIG. 1 is a flow chart showing a procedure for selecting a developer replenishing sequence in a first embodiment of the invention.

FIG. 2 is a front view of the developing device, the developer supply container, and the developer transport unit according to the first embodiment of the present invention.

FIG. 3 is a side sectional view of FIG.

FIG. 4 is a front view of a developer supply amount control wall of the apparatus of FIG. Showing the figure,

5 is a timing chart of drive signals for the developer supply container shown in FIG.

6 is a diagram showing a toner drop amount distribution when toner is supplied at the timing shown in FIG. 5 in the developing device shown in FIG.

FIG. 7 is a diagram showing a toner drop amount distribution when the developer supply container shown in FIG. 2 is continuously driven.

FIG. 8 is a flowchart showing a procedure for selecting a developer replenishing sequence in a second embodiment of the invention.

FIG. 9 is a diagram showing a developer supply container applicable to a second embodiment of the present invention.

FIG. 10 is a diagram showing a relationship between a developer amount and a developer supply amount in a developer container of the apparatus shown in FIG.

FIG. 11 is a diagram showing a difference in developer drop distribution in the developer container longitudinal direction due to a difference in developer supply sequence in the second embodiment of the present invention.

FIG. 12 is a diagram showing a developer supply amount and a developer drop distribution in the developer container longitudinal direction when the developer is supplied in the developer supply sequence shown in FIG. 5 in the second embodiment of the present invention. .

[Explanation of symbols]

 10 Developer Container 11 Toner Sensor (Developer Amount Detection Means) 12 Developer Stirring Member 20 Hopper (Developer Supply Container) 30 Developer Conveying Section 31 Screw (Developer Conveying Member)

Claims (1)

[Claims] 1. A developer container for accommodating a developer, a developer amount detecting means for detecting the amount of the developer in the developer container, and a developer based on the output of the developer amount detecting means. A developer replenishment control means for replenishing the developer transporting portion formed along the longitudinal direction of the developer container from the supply container, and the developer while transporting the developer in the developer transporting portion in the longitudinal direction. In an image forming apparatus having a developer transporting means for dropping the developer into the container, the developer replenishment control means is configured to replenish the developer for a predetermined time and stop the replenishment for a predetermined time, An image forming apparatus, wherein a predetermined time required for replenishment and a predetermined time required for suspension are set so as to be selected according to an operation mode and an operation state of the image forming apparatus.