JPH03242665A - Image forming device - Google Patents

Abstract

PURPOSE:To excellently improve the flowability of toner in a developing device by setting the actuation time of a stirring means in the developing device under an initial condition longer than at ordinary time when a new developing device is attached. CONSTITUTION:In the case of replacing the developing device 12, such as when the developing device 12 is replaced for the new one or when the developing device 12 having the toner of another color is attached in a device main body 1, a control part 23 receives a signal showing 'the absence of a developing device' from a detection switch 22 first. In such a case, the control part 23 generates a detaching signal, which is stored and held, so that the stirring member 32 in the developing device 12 is actuated under the initial condition before an image forming operation for a longer time than the ordinary time even when the new developing device 12 is attached thereafter and the signal showing 'the presence of a developing device' is outputted from the detection switch 22. Therefore, the toner T in the developing device 12 is thoroughly stirred and the flowability thereof is improved.

Description

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

(Prior Art) In many copying machines, a developing device or a process cartridge incorporating the developing device can be easily attached to and removed from the main body of the apparatus, thereby facilitating maintenance.

However, new developing devices and process cartridges have a problem in that toner inside them becomes uneven or aggregates due to vibrations during transportation, storage conditions, etc., resulting in high toner density. Moreover, even when the toner is installed in the main body of the apparatus, the toner aggregates and becomes denser. As a result, the fluidity of the toner in the developing device deteriorates, causing problems such as poor development, and problems such as erroneous detection by the means for detecting the remaining amount of toner in the developing device.

Therefore, a toner stirring means is provided in the developing device, and when the main power of the lid body is turned on, this toner stirring means is activated as one of the initial conditions before image formation, and the toner in the developing device is activated. The toner is stirred to give fluidity to the toner.

On the other hand, if the toner stirring means is operated for a long time every time the main power is turned on as an initial condition before image formation, the waiting time before starting work will be longer, and the toner stirring time will also be longer, resulting in toner fatigue. This results in problems such as the size of the disk becomes large and its performance deteriorates. In addition, in a small image forming apparatus, other equipment such as a photosensitive tram is rotated together with the toner stirring means, so operating the toner stirring means for a long time will reduce the durability of these equipment. There is also the problem of shrinking it.

Therefore, there is a limit to the time period in which the toner stirring means is operated as an initial condition each time the main power is turned on.

(Invention or Section M to be solved) However, when a new developing device or process cartridge is installed in the main body of the device, the density of the toner in the developing device is large, so the toner is removed before image formation. Even if the stirring means performs normal stirring, the problem arises that the fluidity of the toner within the developing device cannot be sufficiently restored.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus in which the operation of the developer stirring means in the developing device as an initial condition before image formation can be made longer than necessary. It is in.

(Means for Solving the Problems) In order to achieve the above object, the present invention has a developing device that is equipped with a developer stirring means and is detachably installed in the apparatus main body, and the main power supply of the apparatus main body is turned on. In an image forming apparatus in which the developer stirring means is activated for a certain period of time as an initial condition before an image forming operation, such as when the developing device is removed from the main body of the apparatus, a detecting means detects that the developing device is removed from the main body of the apparatus and maintains the detected state. a control means for lengthening the operating time of the developer agitation means as an initial condition in response to the maintenance of the detection state of the detection means; and a release means for canceling the detection state of the detection means after the operation of the control means. It is characterized by having.

(Function) Generally, the developing device is removed from the main body of the device when replacing it with a new developing device or with a developing device containing a different color developer. The developer in the developing device installed in the main body of the apparatus generally aggregates to a high density, and its fluidity becomes very poor.

Therefore, once the developing unit is removed from the main body of the apparatus, this fact is continuously detected by the detection means, and this state is detected by the control means, and when a new developing unit is installed in the main body of the apparatus. With this control means, the operating time of the developer stirring means as an initial condition is maintained longer than usual. After the operation of the control means, the detection state of the detection means is canceled by the release means.

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

First, the I! of the present invention! One embodiment will be explained with reference to FIGS. 1 and 2.

No. 1 UjJ shows a #rIf front view of the image forming apparatus. In the figure, lO is a photosensitive tram which is an image bearing member that rotates in a fixed direction. Around the photosensitive tram lO are a primary charger 11 and a developing device. Image forming equipment such as 12 and cleaning device 13 is installed, and below the equipment is a paper feed cassette 14.
, paper feed roller 15°, registration roller 16. Transfer charger 1
7, conveying the transfer paper P such as the fixing device 18 and the paper discharge tray 19;

Transfer and fixing equipment is installed. In addition, developing device 1
Exposure equipment such as a laser scanner unit 20 and a mirror 21 are arranged above the photosensitive tram 2 and the photosensitive tram 10.

That is, when the photosensitive tram 10 uniformly charged by the negative charger 17 is exposed to image light from the laser scanner unit 20 via the mirror 21, an electrostatic latent image is formed on the photosensitive tram 10. . The electrostatic latent image is directed toward the developing device 12 as the photosensitive tram 10 rotates, and the developing device 12
Toner T, which is a developer, is supplied and visualized as a toner image. This toner image is transferred onto the transfer paper P via the transfer charger 17, and the photosensitive tram l
The remaining toner of O is removed by the cleaning device 13 and prepared for the next image formation.

On the other hand, the transfer paper P is transferred from the paper feed cassette 14 to the paper feed roller 15.
After being taken out one by one through the transfer paper P, the transfer paper P is sent to the registration roller 16, timed by the registration roller 16, and routed to the photosensitive tram 10. The photosensitive tram 10 via the device 17
The upper toner image is transferred. The transfer paper P on which the toner image has been transferred is sent to a fixing device 18, where the toner image is fixed as a permanent image and then stacked on a paper discharge tray 19.

The developing device 12 is disposed close to the photosensitive tram IO, and includes a developing roller 30 that supplies toner T to the photosensitive tram 10;
A toner hopper 31 that stores and holds toner T, an agitating member 32 that agitates the toner T in the toner hopper 31, gives fluidity to the toner T, and supplies the toner T toward the developing roller 30. It consists of The developing device 12 is detachably installed in the main body l of the image forming apparatus, making it easy to replace the developing device 12 when the toner T is used up. In addition, it is easy to replace the developing device 12 with a different color toner T.
Responding to requests for color images.

That is, the developing device 12 is positioned in the developing device mounting portion 2 in the apparatus main body 1, and when the developing device 12 is removed from the device main body 1, the developing device 12 and the developing device mounting portion 2 are removed from the main body as indicated by the arrow in FIG. After moving the developing device 12 slightly to the right, open the front door of the main body of the apparatus and pull it out on the front side of the page, that is, in front of the main body.When installing the developing device 12 on the main body l of the apparatus, follow the steps above. You can do exactly the opposite.

Further, a detection switch 22 consisting of a photointerrupter is attached to the developing device mounting portion 2, and the detection switch 22
By detecting the shielding plate 33 of the developing device 12, it is possible to detect that the developing device 12 is installed in the main body l of the apparatus. A signal from this detection switch 22 is transmitted to a control section 23 within the main body l of the apparatus.

Here, when turning on the main power source (not shown) of the main body l of the apparatus and starting image forming work, it is necessary to satisfy certain initial conditions before starting the work. One of these initial conditions is the operation of the stirring member 32 within the developing device 12.

This is because there is generally a considerable time lag between when the main power is turned on and the next time the main power is turned on, so the toner T in the toner hopper 31 of the developing device 12 also aggregates and densifies due to its own weight and flows. If the stirring member 32 is activated suddenly during image formation, the toner T in the toner hopper 31 or the developing roller 30 may be damaged.
This is because there is a problem that the liquid is not sufficiently stirred and moved toward the . That is, prior to image formation, the stirring member 32 is operated for a predetermined period of time in response to a signal from the control section 23, thereby increasing the fluidity of the toner T.

In addition, open the front door of the main body of the device and clean the jam or remove the developing device 12.
Even when the developing device 12 is replaced, etc., the agitating member 32 is activated as an initial condition before the image forming operation, since vibrations etc. are applied to the developing device 12, leading to agglomeration of the toner T, etc.

However, the operation time of the stirring member 32 as an initial condition is generally limited to a short period of time because various adverse effects will occur if the operation of the stirring member 32 continues for a long time.

However, when a new developing device 12 is installed in the apparatus main body l, the toner T in the toner hopper 31 is not normally used in the apparatus main body l due to vibration during transportation or long-term storage of the developing device 12. Toner T in the developing device 12
This is because the degree of densification is high and the fluidity is very poor compared to .

Even if the toner T in the developing device 12 is stirred by the stirring member 32 under normal initial conditions, its fluidity cannot be sufficiently restored.

Therefore, in the control section 23, when the signal from the detection switch 22 is switched from "developing device present" to "developing device not present", a removal signal is generated and stored in the memory. When a new developing device 12 is installed in the printer 1 and an image forming operation is to be started, the operating time of the stirring member 32 as an initial condition is maintained longer than in the normal case. For this purpose, a backup power source is provided in the control section 23 so that the # record removal signal can be stored and retained even if the main power source of the main body 1 of the apparatus is not turned on.

As shown in FIG. 2(b), if the "no developing device" signal is received from the control unit 23 or the detection switch 22, the agitating member 32 in the developing device 12 is turned on when the main power is turned on. During the initial conditions before the image forming operation after the front door is opened and closed, the operation is performed only for a short normal operation time T.

On the other hand, when the developing device 12 is replaced, such as when the developing device 12 is replaced with a new one, or when a developing device 12 containing toner of a different color is installed in the apparatus main body l, the control unit 23 is initially , receives a "developing unit absent" signal from the detection switch 22.

In this case, the control unit 23 generates a removal signal,
In order to memorize and retain this, a new developing device 12 is then installed.
Even if the detection switch 22 outputs a "developing unit present" signal, the agitating member 32 in the developing unit 12 is not activated normally during the initial conditions before the image forming operation, as shown in FIG. 2(a). By operating for a long operating time 7 + (T I > 72), the toner T in the developing device 12 is sufficiently agitated and its fluidity is increased.

Incidentally, when the operation of the stirring member 32 for T1 time is completed, the removal signal of the control section 23 is canceled.

As described above, since the stirring means 32 of the developing device 12 is operated for a longer time than usual when necessary, the toner T
Problems such as deterioration of the image forming apparatus and prolongation of waiting time do not occur, and the problem of increasing the density of the toner T in the developing device 12 is also solved, making it possible to form a good image with such an image forming apparatus.

Next, a second embodiment of the present invention will be described with reference to FIGS. 3 to 5. 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 the first embodiment, "no developing device" is detected from the detection switch 22.
In this embodiment, the memory retention function of the control section 23 is eliminated, and the detection switch 40 side displays "no developing device" until a predetermined time. The signal continues to be sent to the control unit 23.

That is, as shown in FIG.
The upper part 41a of the lever 41 slightly protrudes from the upper part 41a, and the lever 41 is pivoted to the main body l of the apparatus via a support shaft 41d in the middle thereof, and the hook on the upper part of the support shaft 41d is connected to the part 41c and the spring support part 43 of the apparatus main body l. A tension spring 42 is attached between the lever 41 and the lever 41, and the lever 41 is moved counterclockwise in FIG. energize. Further, a connecting rod 46 of a solenoid 45 is pivotally supported on the lower part 41b of the lever 41, and a detection switch 40 consisting of a microswitch is disposed on the right side of the upper part 41a of the lever 41 in FIG.

When the developing device 12 is removed from the main body 1 of the apparatus, as shown in FIG. It attempts to rotate clockwise around the support shaft 41d against the force of the spring 42. When this lever is rotated clockwise to a certain extent, as shown in FIG. Conversely, this lever 41 is rotated clockwise by the tension spring 42, and the upper part 41a of the lever 41 is sunk below the attachment/detachment passage 3, and the detection switch 40 is rotated clockwise by the tension spring 42. It will be suppressed by force.

In this way, the detection switch 40 is connected to the developing unit 1 from the main body l of the apparatus.
The control unit 2 sends a “no developing unit” signal indicating that the developer unit 2 has been removed.
3 will continue to be sent.

Note that even if a new developing unit 12 is installed in the apparatus main body l, the upper part 41a of the lever 41 is located below the attachment/detachment passage 3.
The detection switch 40 continues to send the above signal to the control section 23. Therefore, when an image forming operation is to be started by turning on the main power, etc., the developing device 1 is
The stirring member 32 in 2 can be operated for a slightly longer time than usual based on a command from the control unit 23. Incidentally, reference numeral 47 is a stopper for preventing a large force from being applied by the tension spring 42 to the detection switch 40.

When the operation of the stirring member 32 is completed, the solenoid 45 is activated and the connecting rod 46 is activated, as shown in FIG.
Since the lever 41 is rotated counterclockwise through the lever 41, the lever 41 returns to the initial state indicated by the third [ ], and the "no developing device" signal from the detection switch 4o is released.

As described above, it is possible to obtain the same effects as in the first embodiment in this embodiment as well.In this embodiment, since the control section 23 does not particularly need to have a memory function, the control section 23 has a backup power source. It has the advantage that it is not necessary.

Next, a third embodiment of the present invention will be described with reference to FIGS. 6 to 8. It should be noted that components having the same -am functions as those related to the first embodiment are given the same reference numerals and their explanations will be omitted.

In the second embodiment, the signal from the detection switch 40 is transmitted to the control unit 2.
3, and the developing device 12 is
In this embodiment, the stirring member 32 inside was operated for a rather long time, and all of the above operations were performed mechanically.

That is, as shown in FIG.
In contrast, a lever 41 and a tension spring 42 similar to those in the second embodiment are provided so that the lower part 41b of the lever 41 is engaged with the recessed portion of the rook 50. Rook 50 is a honey clutch 5
1 to the drive shaft 52, and from this rook 50, the stirring member 3 of the developing device 12 is connected via a power transmission means 53.
The rotational force from the drive shaft 52 is transmitted to the second rotating gear 35. Here, when the fly clutch 51 is engaged with the rook 50 or the lever 41, the drive shaft 5
If the rotational force of the drive shaft 52 cannot be transmitted to the rook 50 or the engagement between the rook 50 and the lever 41 is released, the rotational force of the drive shaft 52 is transmitted to the rook 50 and is transmitted from the rook 50 via the power transmission means 53. The stirring means 32 of the developing device 12 is operated for a slightly longer time than usual under the initial conditions. Incidentally, on the left side of the lever 41 in FIG.
4 are arranged.

As shown in FIG. 7, when the developing unit 12 is removed from the apparatus main body l, the lower protrusion 34 or the upper part 41a of the lever 41 is pushed down to some extent around the lever 41 or the support shaft 41b. When rotated clockwise, the tension spring 4
2, the lever 41 is rotated until its lower portion 41b engages with the cam 54.

As a result, the engagement between the lever 41 and the rook 5o is released, so a new developing device 12 is installed in the main body l of the apparatus, and
When image forming work is to be started by turning on the main power, etc., the drive shaft 52, spring clutch 51.
Windmill 50. Via the power transmission means 53, the stirring member 32 in the developing device 12 is operated for a slightly longer time than under normal initial conditions. When the operation of the stirring member 32 is completed, the cam 54 rotates one revolution as shown in FIG. 8, and the lever 41 returns to the state shown in FIG. 6.

As mentioned above, in this embodiment as well, the first. Is it possible to obtain the same effect as in the second embodiment? In this embodiment, the first
．． Unlike the second embodiment, this embodiment has the advantage that the configuration of the control section 23 is simple because no electrical signals are used.

Here, it is assumed that the drive shaft 52 and the cam 54 are always rotated regularly, regardless of whether the developing unit 12 is attached or detached, under initial conditions such as when the main power is turned on to the main body l of the apparatus. Further, it is assumed that under normal initial conditions, the stirring member 32 in the developing device 12 is operated for a short time by a signal from the control section 23.

Further, in the first to third embodiments described above, the developing device 1
The description has been made for the case where the developing unit 2 is attached to and detached from the apparatus main body l alone, but the case is not limited to this.
, also in the case where the developing device 12 is assembled into a process cartridge together with a photosensitive tram lO, etc., which is a device, and the developing device 12 is attached to and detached from the apparatus main body l via the process cartridge.

Of course, the present invention can also be applied.

(Effects of the Invention) As is clear from the above description, according to the present invention, when the developing device is once removed from the apparatus main body and a new developing device is installed inside the apparatus main body, the agitation of the developing device under the initial conditions is improved. Since the operating time of the means is longer than usual, the fluidity of the developer can be sufficiently increased before the image forming operation, even in new developing devices in which the internal developer has a higher density of agglomeration than normal ones. It is possible to form an appropriate image using this developing device.

Further, since there is no need to constantly operate the stirring means for a long time under the initial conditions, problems such as fatigue of the developer do not occur.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of the image forming apparatus according to the first embodiment, FIG. 2 is a diagram showing the operation time of the stirring member under the initial conditions of the developing device of the same image forming apparatus, and FIG. 3 is a diagram showing the operation time of the stirring member according to the second embodiment. FIGS. 4 and 5 are side views of the means for detecting removal of the developing device of the image forming apparatus according to the example, FIGS. 7 and 8 are side views of the means for operating the agitation member during the initial conditions of the developing device of the image forming apparatus according to the third embodiment.
FIG. 3 is an explanatory view of the operation of means for operating the stirring member shown in the figure. Engineering...Device body, 12...Developer, 22.40...
・Detection switch (detection means) 23...Control unit (control means), 41...Lever (detection means), 45...Solenoid (release means), 50...Rook (control means) 54
--Cam (release means). #Applicant Canon Co., Ltd.

Claims (2)

[Claims] (1) A developer is provided with a developer stirring means and is detachably installed in the apparatus main body, and the developer is used for a certain period of time as an initial condition before an image forming operation such as when turning on the main power of the apparatus main body. In an image forming apparatus in which an agitating means is operated, a detecting means detects that the developing unit is removed from the apparatus main body and maintains the detected state; An image forming apparatus comprising: a control means for lengthening the operating time of the developer stirring means; and a release means for releasing the detection state of the detection means after the control means is operated. (2) The developing device is installed in a process cartridge which is detachably attached to the apparatus main body, and the developing device is detachably attached to the apparatus main body via the process cartridge. image forming device.