JPH10268725A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a jamming of a toner pipe, without replacing the toner pipe by providing toner jamming detecting means, and controlling means controlling so as to perform the toner pipe jamming prevention sequence for removing the toner stack in the toner pipe in accordance with the detecting result. SOLUTION: This image forming device is capable of detecting the toner jamming in the waste toner pipe 12a by comparing the toner quantity removed by cleaning means 11 removing the residual toner caused by the image forming with the toner quantity actually recovered in a recovering vessel 13. Exactly, the device is provided with the toner weight detecting means 14 for detecting the quantity of the recovered waste toner T4 in the recovering vessel 13, so that the waste toner quantity recovered in the recovering vessel 13 can be detected from the toner weight. Moreover, the device is provided with the controlling base plate 15 therein comprising the controlling means controlling the image forming operation, and the controlling base plate 15 is made so as to estimate the toner removing quantity by the cleaning means 11 from the image signal at the time of forming the image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer for forming an image using toner, and more particularly to an image forming apparatus having a waste toner conveying screw.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus, after a toner image formed on an image carrier is transferred to a transfer material, a next image forming process is started so as not to hinder the next image formation. Before the cleaning, the toner remaining on the image carrier is removed using a cleaning device. The removed toner t is generally transferred to a waste toner conveying screw 50 as shown in a longitudinal sectional view of FIG. 11A and an aa sectional view of FIG.
Is rotated and conveyed to a waste toner collecting container 52 through a waste toner pipe 51, and is sequentially accumulated in the container 52. Conventionally, this waste toner pipe 51 is straight as shown in FIG. 11, and the waste toner conveying screw 50 inside is also a straight hard type screw.

However, in recent years, as the internal structure of the main body of the image forming apparatus becomes complicated and space is saved, a waste toner pipe 51 is required.
It has become difficult to arrange them straight. Therefore, in some image forming apparatuses, a partially curved type waste toner pipe 53 is used as shown in a longitudinal sectional view of FIG. 12A and a bb sectional view of FIG. The waste toner transport screw 54 is also a torsion coil spring-like waste toner transport screw 54 that can rotate even if it is curved.

[0004]

However, in the conventional configuration, as shown in the longitudinal sectional view of FIG. 13A and the cc sectional view of FIG. When the waste toner conveying screw 54 is rotated, the curved waste toner pipe
Due to the resistance from 53 walls and waste toner to be transported,
The waste toner conveying screw 54 itself contracts in the rotation center direction C.

Further, since the waste toner transport screw 54 receives a force in the direction J opposite to the waste toner transport direction H, the free end of the waste toner transport screw 54 is pressed and contracted, as shown in FIG. The waste toner conveying screw 54 is further curved inside the curved waste toner pipe 53 and positioned so as to draw the longest locus on the inner surface of the waste toner pipe 53 due to the characteristics of the spring. Therefore, it becomes difficult to apply a conveying force to the waste toner t near the wall surface of the waste toner pipe 53. In particular, as shown in FIG.
Tends to remain without being conveyed, and the waste toner t tends to adhere to the wall surface of the waste toner pipe 53.

If this state continues for a long period of time, the waste toner adheres further to the adhered waste toner, so that the conveyance capability of the waste toner gradually decreases, and the waste toner pipe 53 is clogged. The toner may flow back into the cleaning device and adversely affect image formation. Therefore, conventionally, when the waste toner pipe 53 is clogged, it is necessary to clean the pipe or replace the pipe.

However, cleaning of the pipe is complicated because the pipe 53 must be removed from the apparatus main body, and the cleaning operator may be contaminated by scattering of waste toner.

Further, especially in a high-speed, network-compatible image forming apparatus, the downtime required for cleaning and replacing the pipe 53 must be minimized. Downtime increases when investigating the cause and preparing spare parts.

In recent years, as the speed of the image forming apparatus has been increased, the volume has been increased, and the toner used has been multicolored, the accumulation speed of the waste toner has also tended to increase. It is becoming more important to extend the life of the device body.

The present invention has been developed in view of the above points, and an object of the present invention is to provide an image forming apparatus capable of preventing a toner pipe from being clogged without replacing the toner pipe.

[0011]

A typical configuration according to the present invention for achieving the above object is an image forming apparatus having cleaning means for removing toner remaining on an image carrier after image transfer. A toner collection unit that rotates the torsion coil-shaped toner conveyance screw provided in the toner pipe to collect the toner removed by the cleaning unit into the collection container, and a clogging detection unit for detecting toner clogging in the toner pipe And control means for controlling to execute a toner pipe clogging prevention sequence for removing toner attached to the toner pipe in accordance with the detection result of the clogging detection means.

In the above configuration, when it is detected that the toner pipe is clogged with the toner, a toner pipe clogging prevention sequence is performed to scrape off the toner attached to the inner wall of the toner pipe, thereby preventing the toner pipe from being clogged. Is done.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment according to the image forming apparatus of the present invention will be described with reference to the drawings.

[First Embodiment] A first embodiment will be described with reference to FIGS. FIG. 1 is an explanatory diagram of the overall configuration of the image forming apparatus, FIG. 2A is a diagram illustrating a state in which the toner conveying screw is rotated forward to convey waste toner to a collection container, and FIG. FIG. 3 is a cross-sectional view, FIG.
FIG. 4A is a view for explaining a state in which the toner conveying screw is rotated in the reverse direction to prevent the toner pipe from being clogged, and FIG.
It is B sectional drawing.

Here, as an order of the description, first, the entire configuration of the image forming apparatus will be described, and then, a sequence for preventing clogging of the toner pipe will be described.

<< Overall Configuration of Image Forming Apparatus >> As shown in FIG. 1, this image forming apparatus irradiates a light image based on image information from an optical system 1 to a magnetic drum on a photosensitive drum as an image carrier. (Hereinafter referred to as “toner”). Then, in synchronization with the formation of the toner image, the recording medium 2 is transported from the cassette 3a by the transporting means 3 including a pickup roller 3b and a pair of registration rollers 3c.
In a later-described image forming unit, the toner image formed on the photosensitive drum is transferred to the recording medium 2 by applying a voltage to a transfer roller 4 as a transfer unit.

Further, the recording medium 2 after the image transfer is transferred to the guide plate 3
The sheet is guided to the fixing unit 5 while being guided by d. The fixing means 5 includes a fixing roller 5a containing a heater and a driving roller 5b.
And heat and pressure are applied to the recording medium 2 passing therethrough to fix the transferred toner image. The recording medium 2 is conveyed by a pair of discharge rollers 3e, and is discharged to a discharge section 6 through a reverse conveyance path 3f.

On the other hand, the image forming section rotates a photosensitive drum 7 having a photosensitive layer and uniformly charges the surface thereof by applying a voltage to a charging roller 8 serving as a charging means.
The latent image is formed by exposing the light image from the photosensitive drum 7 to the photosensitive drum 7 via the exposure unit 9, and the latent image is developed by the developing unit 10.

The developing means 10 sends out the toner T1 in the toner hopper 10a by a toner sending member (not shown), rotates a developing roller 10b containing a fixed magnet, and applies a triboelectric charge by a developing blade 10c. The formed toner layer is formed on the surface of the developing roller 10b, and the toner is transferred to the photosensitive drum 7 in accordance with the latent image, thereby forming a toner image and visualizing the toner image. After applying a voltage having a polarity opposite to that of the toner image to the transfer roller 4 to transfer the toner image to the recording medium 2, the cleaning unit 11
Thus, the toner remaining on the photosensitive drum 7 is removed and collected.

The cleaning means 11 has a structure in which the toner remaining on the photosensitive drum 7 is scraped off by the cleaning blade 11a and the waste toner T2 is sequentially stored in the cleaning container 11b. The waste toner T2 collected in the cleaning container 11b is collected by the waste toner collecting means 12 into the collecting container 13.

The waste toner collecting means 12 is constructed as shown in FIGS. 2 (a) and 2 (b). In FIG. 2, reference numeral 12a denotes a waste toner pipe, which is provided with a toner discharge port 11d by a transport screw 11c provided in a container 11b of the cleaning means 11.
It forms a transport path for transporting the waste toner discharged from the container to the waste toner collecting container 13, and is formed in a curved shape. A waste toner conveying screw 12b is rotatably provided in the waste toner pipe 12a. The waste toner conveying screw 12b is formed of a torsion coil spring member, and is rotatable even in a state of being curved along the waste toner pipe 12a. The waste toner conveying screw 12b is drivingly connected to a screw motor 12d via a gear train 12c, and is rotated forward and backward by the forward and reverse rotation of the motor 12d.

Thus, the waste toner conveying screw 12b
Is rotated forward (rotation in the direction of arrow A in FIG. 2B), the waste toner in the waste toner pipe 12a is transported in the direction of arrow H in FIG. 2A, and the waste toner discharged from the toner discharge port 11d is discharged. Is collected in the collection container 13.

{Structure of Toner Pipe Clogging Prevention Sequence} In the waste toner collecting means having the waste toner conveying screw in the form of a torsion coil spring, the wall surface of the curved waste toner pipe 12a and the waste Waste toner transport screw due to resistance received from toner
12b contracts in the direction of the center of rotation (the direction of arrow C in FIG. 2B), and further receives a force in the direction J opposite to the waste toner conveying direction H. Therefore, the waste toner conveying screw 12 having a spring property is positioned so as to draw the longest locus in the waste toner pipe 12a, and as a result, the waste toner T3 in the curved portion of the waste toner pipe 12a remains without being conveyed. Will do.

In the present embodiment, when it is detected by the clogging detecting means that waste toner is clogged in the curved portion or the like of the waste toner pipe 12a, the waste toner T3 remaining in the curved portion or the like is removed to remove waste toner. The pipe 12a is configured to prevent clogging. Next, a sequence configuration for that purpose will be described.

The clogging detecting means according to this embodiment compares the amount of toner removed by the cleaning means 11 which may be caused by image formation with the amount of toner actually collected in the collecting container 13 to thereby reduce the waste toner pipe 12a. Is detected. That is, a toner weight detecting means 14 for detecting the amount of waste toner T4 collected in the collection container 13 is provided, and
In FIG. 13, the amount of waste toner collected can be detected.

A control board 15 which constitutes a control means for controlling an image forming operation is provided in the apparatus. The control means controls the amount of toner removal by the cleaning means 11 based on an image signal at the time of forming an image. Is to predict. That is, when the image signal is large, the amount of toner to be developed is also large, so that the amount of toner remaining after being transferred to the recording medium 2 is also large, and as a result, the amount of toner removed by the cleaning unit 11 is large. On the other hand, when the image signal is small, the amount of toner removed by the cleaning unit 11 is small, contrary to the above. For this reason, the amount of toner removed by the cleaning unit 11 is predicted based on the image signal.

Therefore, the sequence for preventing the clogging of the waste toner pipe 12a, as shown in the flowchart of FIG. Is greater than or equal to a predetermined range (S1). When the difference is equal to or more than a certain value, the waste toner adheres to the curved portion of the waste toner pipe 12a, and the pipe 12a may be clogged. Therefore, in this case, it is determined whether or not the image forming operation is being performed (S2). If the image forming operation is being performed, the image forming operation is terminated, and the waste toner conveying screw 12b is reversely rotated for a predetermined time to prevent clogging. Perform the operation (S
3).

When the waste toner conveying screw 12b is rotated in the reverse direction (rotation in the direction of the arrow B in FIG. 4B), the waste toner conveying screw 12b is bent by the wall surface of the curved waste toner pipe 12a and the resistance received from the conveyed waste toner. In contrast to the case where the waste toner is transported to the collection container 13, the waste toner pipe 12 a
In the direction of the wall (in the direction of arrow D in FIG. 4 (b)).
The waste toner remaining on the wall surface of 12a is scraped off. As a result, the inner wall of the waste toner pipe 12a is cleaned, and the clogging of the waste toner pipe 12a can be prevented for a long period of time without cleaning or replacing the waste toner pipe 12a.

The amount of toner collected in the collection container 13 is
In addition to the above-described configuration in which the detection is performed based on the toner weight, the detection can also be performed using, for example, a photo interrupter.

[Second Embodiment] In the above-described first embodiment, an example in which a clogging detection unit detects pipe clogging by comparing the amount of toner in the collection container 13 with the amount of collected toner predicted from an image signal. As described above, an example in which a pipe clog is detected based on the value of the rotation torque of the waste toner conveying screw 12b will be described as a second embodiment with reference to FIGS. FIG. 5 (a) is an explanatory view of the configuration of the toner collecting means according to the second embodiment, FIG. 5 (b) is a sectional view taken along line CC of FIG.
FIG. 7A is a diagram illustrating a state when the waste toner conveying screw is over torque, FIG. 7A is a diagram illustrating a state when the waste toner pipe is cleaned in the second embodiment, and FIG. . Further, the configuration of the image forming apparatus using the toner collecting unit is the same as that of the above-described first embodiment, and the same members as those of the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

The waste toner conveying screw 12b according to this embodiment has a torque limiter 16,
a is integral with the shaft of the screw 12b and is engaged with the gear member 16b in the thrust direction. The gear member 16b has gear teeth meshing with the motor gear 17 on the outer periphery, and is pressed by a spring 16c against the engaging member 16a. When a torque equal to or more than a predetermined value is applied to the gear member 16b, the gear member 16b
b slides against the pressing force of the spring 16c. 16d is a torque detection switch,
It is turned on and off by the movement of the gear member 16b.

In the above configuration, as shown in FIG. 5, when the waste toner conveying screw 12b is rotated forward (rotation in the direction of arrow A in FIG. 5B), the toner removed by the cleaning means 11 is the same as in the first embodiment. Is transported and collected to the collection container 13. At this time, when the waste toner T4 does not adhere much to the waste toner pipe 12a, the rotation torque of the waste toner conveying screw 12b is less than a certain value.

However, when the amount of the waste toner T4 increases, the rotational torque of the screw 12b increases due to the resistance. When the rotation torque becomes equal to or more than a predetermined value, as shown in FIG. 6, the gear member 16b is disengaged from the engagement member 16a, and slides in the direction of arrow E in FIG. As a result, the engagement between the gear member 16b and the motor gear 17 is released, the screw 12b is released from contracting in the direction of arrow C in FIG. 5B, and the torque detection switch 16d is turned on to turn off the waste toner conveying screw 12b. Is detected to exceed a predetermined value.

Based on the above detection, the control means reversely rotates the screw motor 12d for a predetermined time. As a result, when the image forming operation is stopped as in the first embodiment, the waste toner screw 12b reversely rotates for a certain time as shown in FIG. 7, and the screw 12b is moved toward the wall surface of the waste toner pipe 12a. The waste toner remaining on the wall surface of the pipe 12a after being enlarged is scraped off. FIG. 8 is a flowchart showing the control procedure.

Even with the above-described structure, the clogging of the waste toner pipe 12a can be prevented for a long period of time without special cleaning or replacement of the waste toner pipe 12a as in the first embodiment. Further, it is possible to prevent an increase in torque applied to the drive system due to clogging of the waste toner pipe 12a, so that stable image formation can be performed for a long time.

As described above, in addition to the detection by the torque limiter, the current value of the screw motor 20d is detected in real time, and when a predetermined current value is exceeded, a sequence for preventing the waste toner pipe 12a from being clogged is performed. Is also good.

[Third Embodiment] FIGS. 9 and 10 show the construction of a toner collecting means in which the waste toner conveying screw 12b according to the second embodiment is manually rotatable.
This will be described with reference to FIG. FIG. 9 is an explanatory diagram of a configuration of a toner collecting unit according to the third embodiment, and FIG. 10 is an explanatory diagram of a state in which the waste toner conveying screw is manually rotated. Also in this case, the same members as those in the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted.

9 and 10, the torque limiter 16
A hook 18 is engaged with one end of the gear member 16b, and the gear member 16b can be slid with the hook 18. The end of the waste toner conveying screw 16b on the collection container side is a waste toner pipe 16a.
And a locking hole 19 is provided in this protrusion,
The handle 20 can be detachably engaged with the engagement hole 19.

Accordingly, as described in the second embodiment, when the rotation torque of the waste toner conveying screw 16b becomes a predetermined value or more, not only is the clogging prevention sequence automatically performed, but also the The user can manually perform the clogging prevention operation as needed. That is, when the user wants to perform the clogging prevention operation, the gear member 16b is slid with the hook 18 to release the engagement between the gear member 16b and the motor gear 17, as shown in FIG. As a result, the waste toner conveying screw 16b becomes freely rotatable.

Next, a handle 20 is locked and attached to the locking hole 19, and the handle 20 is rotated in a direction in which the winding of the waste toner conveying screw 12b in the form of a torsion coil spring is loosened. Thus, the waste toner remaining on the wall surface of the waste toner pipe 12a is removed by the screw 12b expanded toward the wall surface of the waste toner pipe 12a in the same manner as in the above-described clogging prevention sequence operation.

With this configuration, if the torque detection switch 16d fails, the waste toner pipe 12
Even when the clogging prevention sequence is not performed, the waste toner pipe 12a can be manually cleaned.

[Other Embodiments] In the first and second embodiments described above, an example is shown in which the sequence for preventing the clogging of the waste toner pipe 12a is performed when the image forming operation is stopped. Is not necessarily stopped during image formation, but can be performed during image formation operation.

In the above-described embodiment, a clogging prevention sequence is performed when the waste toner amount exceeds a certain weight or when the driving torque of the waste toner conveying screw 12b becomes a certain value or more. However, if an apparatus status reporting system capable of remotely detecting the image formation counter value, the sensor value, and the like detected by the image forming apparatus using a telephone line or the like is used, the waste toner pipe can be used by the system. The timing of clogging of 12a can be known by transmitting a pipe replacement time notification signal. Therefore, the clogging prevention sequence can be executed from a remote location based on the pipe replacement time notification signal.

In the above-described embodiment, a printer is illustrated as an example of an image forming apparatus. However, the present invention is not limited to this. For example, a copier or a facsimile apparatus can be similarly applied. Of course.

[0045]

The present invention is constructed as described above.
When it is detected that the toner pipe is clogged with the toner, a toner pipe clogging prevention sequence is performed to scrape off the toner attached to the inner wall of the toner pipe, thereby preventing the toner pipe from being clogged. Therefore, clogging of the toner pipe can be prevented without replacing the toner pipe, and stable image formation can be performed for a long period of time.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an overall configuration of an image forming apparatus.

FIG. 2 is a diagram illustrating a state in which a toner conveying screw is rotated forward to convey waste toner to a collection container.

FIG. 3 is a flowchart illustrating a control procedure of a toner pipe clogging prevention sequence.

FIG. 4 is a diagram illustrating a state in which the toner conveying screw is rotated in the reverse direction to prevent the toner pipe from being clogged.

FIG. 5 is an explanatory diagram of a configuration of a toner collecting unit according to a second embodiment.

FIG. 6 is a diagram illustrating a state when the waste toner conveying screw is over torque.

FIG. 7 is a diagram illustrating a state when cleaning a waste toner pipe according to a second embodiment.

FIG. 8 is a flowchart showing the control procedure.

FIG. 9 is an explanatory diagram of a configuration of a toner collecting unit according to a third embodiment.

FIG. 10 is a diagram illustrating a state in which the waste toner conveying screw is manually rotated.

FIG. 11 is an explanatory view of a conventional linear waste toner conveying screw.

FIG. 12 is an explanatory diagram of a configuration of a waste toner conveying screw rotatable in a curved waste toner pipe.

FIG. 13 is a diagram illustrating a state in which waste toner adheres to a wall surface of a waste toner pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical system 2 ... Recording medium 3 ... Conveying means 3a ... Cassette 3b ... Pickup roller 3c ... Registration roller pair 3e ... Discharge roller pair 3f ... Reverse conveyance path 4 ... Transfer roller 5 ... Fixing means 5a ... Fixing roller 5b ... Driving roller Reference Signs List 6 discharge section 7 photoconductor drum 8 charging roller 9 exposure section 10 developing means 10a toner hopper 10b developing roller 10c developing blade 11 cleaning means 11a cleaning blade 11b cleaning container 11c transport screw 11d ... toner outlet 12 ... waste toner collecting means 12a ... waste toner pipe 12b ... waste toner conveying screw 12c ... gear train 12d ... screw motor 13 ... collection container 14 ... toner weight detecting means 15 ... control board 16 ... torque limiter 16a ... Joint member 16b… Gear member 16c… Spring 16d… Torque detection Switch 17 ... motor gear 18 ... hook 19 ... locking hole 20 ... handle

Claims (7)

[Claims] 1. An image forming apparatus having a cleaning unit for removing toner remaining on an image carrier after image transfer, comprising: a toner conveying screw having a torsion coil shape provided in a toner pipe with the toner removed by the cleaning unit. A toner collection unit that rotates to collect the toner in the collection container, a clogging detection unit that detects clogging of the toner in the toner pipe, and removes the toner attached to the toner pipe according to a detection result of the clogging detection unit. Control means for controlling to execute a toner pipe clogging prevention sequence. 2. A clogging detection unit according to claim 1, wherein a difference between a toner amount obtained from a toner weight in said collection container and a toner removal amount by a cleaning unit predicted from an image signal is equal to or more than a predetermined value. The image forming apparatus according to claim 1, wherein the image is detected. 3. The image forming apparatus according to claim 1, wherein the clogging detection unit detects the toner clogging when the rotation torque of the toner conveying screw becomes equal to or more than a predetermined value. 4. The image forming apparatus according to claim 1, wherein in the sequence for preventing clogging of the toner pipe, the coil of the toner conveying screw is rotated for a predetermined time in a loosening direction. 5. The image forming apparatus according to claim 1, wherein the toner pipe is curved. 6. The image forming apparatus according to claim 1, wherein the toner conveying screw is manually rotatable. 7. The image forming apparatus according to claim 1, wherein the toner pipe clogging prevention sequence is performed based on a pipe replacement time notification signal from an apparatus status reporting system.