JPH04162061A - Image forming device - Google Patents

Abstract

PURPOSE:To reduce the maximum value of load torque required for drive source so as to make the drive source compact by time-sharing the driving period of a developing apparatus and that of a toner makeup device. CONSTITUTION:In order to perform toner makeup during the driving stop period of a developing apparatus 32, the driving of a developing device is branched from the main motor 10 of an image forming device body. A developing apparatus driving clutch 40 is provided to perform the intermittent operation of the developing apparatus 32. For this reason, there are provided a developing roller driving control means 41 for driving a roller 30 in accord with the period of a latent image formed at a sensitized drum 36 passing in front of the developing apparatus 32 (developing roller 30), and a toner makeup device driving control means 42 for driving a toner makeup device 35 during the stop period of the developing roller 30 other than the period of the developing roller 30 being driven by the control means 41. Both control means 41, 42 are stored as a program in a CPU.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an image forming apparatus such as a copying machine, a fax machine, a printer, etc., and in particular, a system for automatically replenishing toner when the amount of toner in a developing device decreases. The present invention relates to an image forming apparatus that can perform

[Conventional technology]

2. Description of the Related Art Conventionally, in developing devices in image forming apparatuses, toner replenishing devices that automatically replenish toner when the amount of toner in the developing device decreases are often used.

When driving the developer, various methods are known, such as branching off from the drive source of the main body of the image forming apparatus, or providing a dedicated developer drive source.

In addition, when driving the toner replenishing device, there is a method in which the toner replenishing device is driven intermittently only when necessary, such as by branching from the drive source of the image forming apparatus main body or from the developing device drive source, as described above. Are known.

In conventional image forming apparatuses of this kind, the developing device is generally operated continuously during the image forming process, and toner replenishment is performed intermittently.
Japanese Patent No. 73 also proposes a system in which the developing device is driven only when a developing action is necessary in the image forming process, and the operation of the developing device is stopped when no development is being performed.

FIGS. 8 and 9 show two conventional examples of drive systems for a developing device and a toner replenishing device.

In FIG. 8, the driving force from the single driving source main motor 10 is transmitted through the main chain 11 to the developer drive gear 12.
, is transmitted to the toner replenishment clutch 13.

In FIG. 9, the developing device is provided with a dedicated drive source, that is, a developing device driving motor 20, and the driving force from the developing device driving motor 20 is transmitted to the developing device driving belt 21, to the developing device driving gear 22, and toner replenishment. This will be communicated to Kula Nchi 23.

The developer drive gear 12.22 is connected directly or indirectly to the developer rollers. For this reason, the developing unit is operated at approximately 100 kHz during image forming operation in synchronization with the main motor 10 in FIG. 8 and in synchronization with the developing unit drive motor 20 in FIG.
Operates at 0% duty.

Further, the toner replenishment clutch 13.23 is connected directly or indirectly to the toner replenishment roller. The toner replenishment clutch 13.23 includes a toner concentration sensor (not shown).
It operates intermittently depending on signals such as.

[Problem to be solved by the invention]

However, in the conventional image forming apparatus as described above, the developing device operates almost continuously during image formation, whereas the toner replenishing device operates intermittently only when necessary.
The drive torque required for the drive source is the sum of the drive torque of the developing device and the drive torque of the toner replenishing device.

This relationship is shown in FIG. FIG. 10 shows drive sources in the conventional technology (main motor 10, developer drive motor 20)
It is a pattern diagram showing the load torque applied to. however,
The load torque of the main body of the image forming apparatus is excluded.

Here, the drive source is designed with respect to the total load torque. In other words, the load torque (A+
It is designed with a margin for B). Therefore, there is a problem in that the drive source becomes larger due to the need to generate the load torque (A+B).

Furthermore, when a large drive source is provided, as is clear from FIG. 10, the developing unit operates at almost 100% duty, whereas the toner replenishing device operates extremely rarely. Under normal conditions, the load torque B of the toner replenishing device is idle, resulting in poor efficiency.

[Purpose of the invention]

Therefore, the invention according to claim 1 reduces the maximum value of the load torque required for the drive source and downsizes the drive source by time-sharing the drive period of the developing device and the drive period of the toner replenishing device. The object of the present invention is to provide an image forming apparatus that can perform the following steps.

Further, the invention as claimed in claim 2 provides an image forming apparatus in which the developing device and the toner replenishing device can be driven by the same drive source by time-sharing the drive period according to the forward and reverse rotation directions of the drive source. is intended to provide.

[Means to solve the problem]

In order to achieve the above object, the invention according to claim 1 includes: a drive motor that drives a developing roller provided in a developing device in conjunction with an image forming process; and a toner replenishing device that replenishes toner into the developing device. An image forming apparatus comprising: a developing roller drive control means for driving the developing roller in accordance with a period in which a latent image passes in front of a developing device in the image forming process; and a developing roller drive control means driven by the developing roller drive control means. The present invention is characterized by comprising a toner replenishing device drive control means for driving the toner replenishing device during a developing roller stop period other than the developing roller stop period.

In addition, in order to achieve the above object, the invention according to claim 2 provides drive motor control that rotates the drive motor in the forward direction when driving the developing roller, and rotates the drive motor in the reverse direction when driving the toner replenishing device. and a transmission means for transmitting driving force to either the developing roller or the toner replenishing device depending on the forward or reverse rotational direction of the drive motor.

Hereinafter, the present invention will be explained based on examples.

1 to 4 are diagrams showing an embodiment of the invention as claimed in claim 1. FIG. 1 is a schematic configuration diagram showing the main components of an image forming apparatus according to the invention together with a drive system, and FIG. (a), (b
) is a timing chart showing the load torque generation pattern in the image forming process, FIG. 3 is a flowchart showing the processing procedure, and FIG. 4 is a configuration diagram showing the developing device.

Note that in this embodiment, the same components as in the conventional example are given the same reference numerals, and detailed explanation thereof will be omitted.

First, the configuration will be explained.

In FIG. 4, the developing device is roughly divided into developing roller 3.
The developing device 32 includes a toner hopper 33, a toner replenishing roller 34, and the like. Note that 30 to 35 indicate developing devices for black toner, and 30c to 35c indicate developing devices for color toner. The developing device 32 is required to operate at almost 100% duty during image forming operation for its function of visualizing a latent image. - On the other hand, the toner supply device 35 is
Random intermittent operation is required because it is operated only when the developer concentration is low. For this reason, the driving of the developing device 32 and the driving of the toner replenishing device 35 are generally performed independently.

Incidentally, the developing device 32 is generally driven continuously during the image forming operation, but as described in the above-mentioned Japanese Patent Laid-Open No. 62-1
As shown in Japanese Patent No. 21473, continuous operation is not necessarily required. That is, during the image forming cycle, a return time for the scanner, etc. is required, so a non-developing period necessarily occurs during the image forming cycle or between cycles. As a result, the operation of the developing device 32 is limited to the operation of the photosensitive drum 3.
Only the time it takes for the latent image formed on the image forming apparatus 6 to pass in front of the developing roller 30 is sufficient, and it is possible to temporarily stop the image forming cycle or between cycles.

According to a first aspect of the invention, toner is replenished during the above-mentioned period when the developing device is stopped.

The embodiment shown in FIG. 1 is an example in which the driving of the developing device is branched from the main motor 10 of the main body of the image forming apparatus.

In this embodiment, the method of driving the toner replenishing device is the same as that of the prior art, but the present invention is characterized in that a developing unit drive craft 40 is provided to drive the developing unit intermittently.

For this purpose, in this embodiment, a developing roller drive control means 41 drives the developing roller 30 in accordance with the period in which the latent image formed on the photosensitive drum 36 passes in front of the developing device 32 (developing roller 30). and a toner replenishing device drive control means 42 for driving the toner replenishing device 35 during a developing roller stop period other than the developing roller driving period by the developing roller drive control means 41. Note that the developing roller drive control means 41 and the toner supply device drive control means 42 are stored, for example, as a program in a CPU (not shown) or the like.

Next, the operation will be explained with reference to the load torque generation pattern according to the present invention shown in FIG.

Figure 2 (a) shows the image forming process (image forming cycle)
This shows the presence or absence of a latent image passing in front of the developing device, and FIG. 2(b) shows an example of the load torque generation pattern during the developing device drive period and stop period defined by the presence or absence of the latent image. .

The developing device driving period is determined with some margin before and after the period in which the latent image passes.

Further, the developing device stop period S is defined as the above-mentioned developing device driving period.

The developing roller drive control means 41 controls the developing device drive clutch 40 at timing K in accordance with the illumination of the latent image.
ONL, turns OFF at timing L.

On the other hand, the toner replenishing device drive control means 42 turns the toner replenishing clutch 13 ON at timing M within the developer stop period S, and turns it OFF at timing N.

The processing procedure in this embodiment will be explained below according to the flowchart in FIG.

First, step S waits for timing K to start development.
101), the developer drive clutch 40 is turned on at timing K (step S102). Next, the process waits for timing L to end the development (step S103), and turns off the developer drive clutch 40 at timing L (step S104).

Next, it is determined whether toner replenishment is necessary (step 3105), and if necessary, toner replenishment clutch 1 is activated.
3 is turned 0N10FF at timings M and N (step S106). Then, it is determined whether the image forming process is finished, that is, whether it is a repeat end (step S107), and if YES, the process is finished.

As can be seen from the above flowchart, the developing unit 32, that is, the developing roller 30 is driven only for a period of time necessary for development. This timing can be easily determined by counting the pulses generated in synchronization with the image formation start time by the optical system and the process speed. Further, whether or not toner replenishment is necessary can be easily determined using a developer 4 degree sensor (not shown) or the like.

This toner replenishment signal is randomly generated, but as can be seen from the flowchart, toner replenishment is performed only while the developing device 32 is stopped.

As described above, the load torque applied to the main motor 10 as a drive source has a pattern as shown in FIG. is prevented.

Here, in this embodiment, the maximum value of the required load torque is the load torque A of the developing unit, so the load on the main motor 10 as a drive source is reduced, and the drive source can be downsized. . Further, by downsizing the drive source, various effects such as low noise, low power consumption, weight reduction, and cost reduction can be achieved.

5 to 7 are diagrams showing an embodiment of the invention as claimed in claim 2, FIG. 5 is a main part configuration diagram showing the image forming apparatus according to the invention, and FIG. 6 is an overall diagram showing the drive system thereof. The configuration diagram and FIG. 7 are flowcharts showing the processing procedure. In this embodiment, the same components as those in the above-mentioned example are given the same reference numerals, and detailed explanation thereof will be omitted.

The first characteristic feature of this embodiment is that, as shown in FIG. 6, a dedicated developing device drive motor 20 is provided separately from the main motor 10. As symbolically shown in FIG. 5, when driving the developing device 32 (developing roller 30), the developing device drive motor 20 is rotated in the normal direction, and when driving the toner replenishing device 35, the developing device drive motor 20 is rotated normally. a drive motor control means 50 for reversing the developer drive motor 20; and a drive motor control means 50 for reversing the developer drive motor 20;
Alternatively, the one-way flange 5 for driving the developing device serves as a transmission means for transmitting the driving force to either one of the toner replenishing devices 35.
1 and a one-way clutch 52 for driving the toner supply device,
It is characterized by having the following.

The one-way clutch 51 for driving the developing device (hereinafter simply referred to as one-way clutch 51) is configured so that the developing device driving heald 21 is engaged when the rotating direction of the developing device driving motor 20 is forward rotation as shown by arrow F, for example. The developed developing device driving pulley 53 and the developing device driving shaft 54 are connected. Note that the developing device drive shaft 54 is connected to the developing roller 30 and stirring roller 31 shown in FIG.
It is connected directly or indirectly through gears, etc.

Further, the one-way clutch 52 for driving the toner replenishing device (hereinafter simply referred to as the one-way clutch 51) is such that the developing device driving heald 21 is engaged when the rotating direction of the developing device driving motor 20 is reversely rotated as shown by arrow G, for example. The toner replenishing device drive pulley 55 and the toner replenishing device drive shaft 56 are connected. Note that the toner replenishing device drive shaft 56 is connected directly or indirectly to the toner replenishing roller 34 shown in FIG. 4 via a gear or the like.

Hereinafter, the processing procedure in this embodiment will be explained according to the flowchart shown in FIG.

First, when it comes time to start development, step S2
01), the developing device drive motor 20 is driven to rotate counterclockwise in the direction F in FIG. 5 (step S202).

Here, for the one-way clutches 50 and 51, the direction of the arrow is the locking direction. Therefore, the developing device drive boo'J
The attached one-way clutch 51 is locked, and the developing device drive shaft 54 is driven. Developer drive shaft 54
is directly or indirectly connected to the developing roller 3o and the stirring roller 31, so that the developing operation is performed.

On the other hand, the one-way clutch 52 attached to the toner replenishing device drive pulley 534 is released, and the toner replenishing device drive shaft 56 is not driven.

Thereafter, the developing device drive motor 20 stops at the timing when the development ends (steps 5203 and 5204). If the toner replenishment request signal has not been generated at this point, that is, if the determination in step 5205 is No, the repeat end (
The above process is repeated up to step S207). If the toner replenishment request signal is generated, that is, if the determination in step S205 is YES, the developing device drive motor 2o is rotated clockwise in the direction G in FIG.

This time, the one-way clutch 51 of the developing device driving pulley 53 is released, and the other toner replenishing device driving pulley 55 is released.
One-way clutch 52 attached to is locked.

As a result, the toner supply device drive shaft 56 is driven, and the developer drive shaft 54 is not driven. ) - The toner replenishing device drive shaft 56 is connected to the toner replenishing roller 34, so toner is replenished (Step 1).

PuS 206).

In this way, this embodiment is a further improvement of the previously described embodiment. That is, as in the previous embodiment, since the developing device and the toner replenishing device are selectively driven,
It is possible to achieve miniaturization of the drive source. Furthermore, while the above embodiments provide the developer drive clutch 40 and the toner replenishment clutch 13, and it is necessary to switch ON10FF of the clutch in each drive period,
In this embodiment, by rotating the developing device drive motor 20 in forward and reverse directions, the direction of driving force transmission is automatically determined by the one-way clutches 51 and 52.
Control becomes unnecessary. For this reason, the developer drive clutch 40
The cost of the apparatus, including the cost of the toner replenishment clutch 13, can be reduced.

[Effects] According to the image forming apparatus according to the invention described in claim 1, by time-sharing the driving period of the developing device and the driving period of the toner replenishing device, the maximum value of the load torque required for the driving source can be reduced. The power source can be reduced in size and the drive source can be made smaller.
The price of equipment can be lowered.

Further, according to the image forming apparatus according to the invention described in claim 2, the developing device and the toner replenishing device are operated by the same drive source by time-sharing the drive period according to the forward and reverse rotation directions of the drive source. It is possible to effectively utilize the I/L power generated by the driving source.

[Brief explanation of drawings]

1 to 4 are diagrams showing an embodiment of the invention as claimed in claim 1, FIG. 1 is a schematic configuration diagram showing the main configuration of an image forming apparatus according to the invention together with a drive system, and FIG. (a) and (b) are timing charts showing the load torque generation pattern in the image forming process, Part 3 is a flowchart showing the processing procedure, Fig. 4 is a configuration diagram showing the developing device, and Figs. 5 to 7 are 5 is a diagram showing an embodiment of the invention as claimed in claim 2, FIG. 5 is a configuration diagram of main parts of an image forming apparatus according to the present invention, FIG. 6 is an overall configuration diagram showing a drive system thereof, and FIG. is a flowchart showing the processing procedure, and FIGS. 8 and 9 are diagrams showing a conventional example. FIG. FIG. 10 is a pattern diagram showing the load torque applied to the drive source in the prior art. 41...Developing roller drive control means, 42...
. . . Toner supply device drive control means, 50 . . .
Drive motor control means, 51.52... One-way clutch (transmission means). Figure 3 Figure 4 Figure 5 Father Figure 6 Figure 7 Figure 9 Figure 10 Time (1)

Claims (2)

[Claims] (1) An image forming apparatus comprising: a drive motor that drives a developing roller provided in a developing device in conjunction with an image forming process; and a toner replenishing device that replenishes toner into the developing device; a developing roller drive control means for driving the developing roller in accordance with a period in which a latent image passes in front of the developing device in a process; and a toner replenishing device during a developing roller stop period other than the developing roller drive period by the developing roller drive control means. An image forming apparatus comprising: a toner replenishing device drive control means for driving a toner replenishing device. (2) drive motor control means that rotates the drive motor in the forward direction when driving the developing roller and reversely rotates the drive motor when driving the toner replenishing device; 2. The image forming apparatus according to claim 1, further comprising a transmitting means for transmitting driving force to either the developing roller or the toner replenishing device.