JPH01133088A - Cleaning device for image forming device - Google Patents

Abstract

PURPOSE:To facilitate the maintenance of the title device and to prevent the damage and contamination of the device by providing means for interrupting the driving to a carrying screw when the load exerted on the carrying screw exceeds a prescribed value and a means for detecting the interruption of the driving to the carrying screw. CONSTITUTION:The means 22, 28 for interrupting the driving to the carrying screw 17 when the load exerted on the carrying screw 17 exceeds the prescribed value, the means 31 for detecting the interruption of the driving to the carrying screw 17 when the driving thereof is interrupted and a means for outputting the signal displaying the same are provided to the driving part for driving the carrying screw 17 of the cleaning device constituted in such a manner as to discharge the toner recovered from the surface of an image carrier to the outside by means of the carrying screw 17. Accumulation of the excess toner in a waste toner storage part is thereby surely prohibited and the accumulation state of the toner is easily announced to an operator. The contamination in various parts and the deterioration of the image quality based on the excess toner state are thus prevented.

Description

Detailed Description of the Invention (1) Purpose of the Invention (Industrial Applicability ￥f) The present invention relates to an image forming apparatus using an electrostatic transfer process such as an electrostatic copying machine or a printer, and particularly to a cleaning device thereof. It is.

(Prior art and problems to be solved) A well-known image forming apparatus that repeats the process of supplying charged toner to an electrostatic latent image formed on the surface of an image carrier, developing the latent image, and transferring the latent image to a transfer material. In this case, the toner supplied to the image carrier during development is transferred to the transfer material, but not all of the toner is transferred, so it remains on the image carrier after each transfer in preparation for the next process. It is necessary to remove the residual toner by a cleaning means and to collect the toner that is gradually accumulated.

For this purpose, conventionally, a cleaning device is provided with a conveying screw, and the toner collected from the image carrier is sequentially conveyed to the outside of the cleaning device by the screw, and is further stored in a waste toner container. It is well known that many methods have already been proposed and put into practice.

As can be easily understood, in the toner collection method described above, if the toner container does not have a means to detect the amount of collected toner, excess toner will accumulate in the container and the resulting toner pressure will increase. exerts a braking effect on the drive torque of the conveyance screw, so if this effect becomes excessive, it may damage the conveyance screw or the drive system that drives it, or excessive toner collected in the cleaning area may adversely affect image formation. There is a risk that various inconveniences may occur, such as leakage into the apparatus and contamination of various parts within the apparatus, the transfer material, and the like.

For this reason, for example, a photodetection method using a photoelectric conversion element,
Weight detection methods using microswitches have already been proposed, and these methods have been in practical use for a long time because they each have a certain effect, but there are concerns about their operational stability, and The fluidity of the collected toner in the container tends to change depending on the conditions, and it tends to be stored in an irregular shape inside the container, so malfunctions caused by this have caused a sufficiently satisfactory product to not yet be obtained.

In consideration of the above points, a braking action is applied to the drive side of the conveyance screw according to the amount of accumulated toner, and if this action exceeds a predetermined value, the drive side will idle and prevent damage to various parts. is proposed.

An example of such a device is shown in FIG. 4 and below.

The figure shows a rotating cylindrical image carrier (called a photoreceptor) that has recently been used especially in small-sized copying machines.
This is a cartridge-type image forming apparatus that integrally comprises a cartridge and several members disposed around it, but it goes without saying that the apparatus outlined below is not limited to this type of apparatus. It's a place like no other.

In the illustrated apparatus, a photoreceptor 12, a negative charger 11a, a developing device 13, and a cleaning device 14 arranged around the photoreceptor 12 are integrally constituted by a cartridge 11.

An electrostatic latent image formed on the surface of the photoreceptor 12 rotating in the direction of arrow A by a latent image forming means (not shown) is transferred to the developing device 13.
When the latent image reaches a predetermined position facing the developing device, the latent image is developed by the toner supplied from the developing device, and the toner forming the developed image is transferred to the transfer site provided with the transfer charge 19.
After being transferred to a transfer material (not shown) that is conveyed to the area, the transfer material is separated from the photoreceptor and fed to a fixing area (not shown), and any residue remaining on the photoreceptor that does not contribute to the transfer is removed. As the photoreceptor rotates, the toner reaches a position facing the cleaning device 14, is scraped off from the photoreceptor by the cleaning blade 15, reaches the conveyance screw 17 by the collection roller 16, and is carried by the roller in a direction perpendicular to the plane of the paper. It is transported and discharged from the cleaning device.

As shown in FIG. 5, the photoreceptor 12 is formed in a hollow shape, the toner discharge hole of the cleaning device 14 and the hollow part of the photoreceptor are connected by a pipe 18, and the conveyance screw is Since the pipe extends from inside the cleaning device, the toner discharged from the cleaning device is successively fed into the photoreceptor and stored there.

As can be seen from FIG. 5, the conveyance screw 17 is connected to an input gear Gl connected to a drive source (not shown).

It is driven by a gear 21 disposed on a screw drive section 20 via a gear G2 formed at the end of the photoreceptor 12.

FIG. 6 shows an enlarged view of the drive section 20,
A gear 21 is fitted onto a shaft 25 which is pivotally connected to the casing of the cleaning device 14 and has a conveying screw 17 attached to its end, and a block 22 is disposed adjacent thereto.

The block 22 is fitted onto the shaft 25 and can be formed using any known suitable method, such as using a key and a keyway, or cutting a part of the surface of the shaft 25 and shaping the hole in the block 22 to match the shape. In this way, it is configured such that it can be freely displaced relative to the shaft 25 in the axial direction, and both rotate together.

Further, the block 22 is always biased in the direction of the gear 21 by a spring 23, and
A slope 24a of the protrusion 24 formed in the block 22 engages with a slope 22a of the recess formed in the block 22.

With this configuration, the gear 2 is controlled by the drive input.
1 rotates in the direction of the illustrated arrow, both the slopes 22a,
Due to the locking action of 24a, the conveying screw 17 rotates via the block 22 and the shaft 25, and the toner collected in the cleaning device is conveyed and stored in the hollow part of the photoconductor one by one.

After the hollow part of the photoreceptor is filled with toner, toner continues to be supplied, and the pressure of the toner applies a braking action to the rotation of the conveying screw, which gradually increases and causes the slopes 22a and 24a to Once the locking action due to friction is exceeded, the block 22 is displaced to the left in FIG. The gear will idle, and after that, every rotation of the gear will cause a click due to the instantaneous engagement and disengagement of the two.
You will continue to hear a clicking sound,
It is possible to instruct the operator that the toner is full.

By means of the above means, it is possible to indicate that the toner is full and to reliably prevent an abnormal load from being applied to the drive system, but in a noisy environment it is possible that the collision sound may be missed. In such a case, if one operation is continued, the toner will not be discharged from the cleaning device and will remain in the cleaning device, until the collection roller 16 will close to the opening on the side facing the photoreceptor 12. $7f that may leak out and contaminate various parts inside the device, transfer material, etc.
There is a risk of causing fi.

The present invention has been made in view of the above-mentioned situation, and when the collected toner is transported to a toner storage site by a transport screw, when a predetermined amount or more of toner is stored, the drive system of the transport screw is activated. In a cleaning device that is configured to be shut off, it is possible to reliably detect the amount of toner in the toner storage area, and to ensure stable operation at all times without malfunction or excessive load on the drive system. The purpose of this invention is to provide a leaning device.

(2) 4I features of the invention (technical means for solving the problem, their effects) In order to achieve the above object, the present invention is configured such that the toner collected from the surface of the image carrier is discharged to the outside by a conveying screw. In the cleaning device, the drive unit that drives the conveying screw is provided with a means for cutting off the drive to the conveying screw when the load applied to the conveying screw exceeds a predetermined value, and a means for cutting off the drive to the conveying screw when the drive to the conveying screw is cut off. The present invention is characterized in that means for detecting this and means for outputting a signal to display this are provided.

With q configured in this way, in a cleaning device configured to accumulate waste toner in the storage section, it is possible to reliably prevent excessive toner from accumulating in the storage section, and to easily control the toner accumulation state. This can prevent contamination of various parts and deterioration of image quality due to excess toner.

(Description of Embodiment) FIG. 1 shows an embodiment of the present invention, in which a drive unit 20 for driving a conveying screw of a cleaning device in a copying machine similar to that described in FIG. This figure shows the structure of the parts corresponding to those described above, and the same reference numerals are given to the parts corresponding to those described above.

The drive unit 20 is pivoted at a suitable position on the casing F of the cleaning device, and has a shaft 25 to which the conveying screw 17 is attached.
It is assumed that a gear 21 is loosely fitted into the gear 21, and a driving force is inputted to the gear from a driving source (not shown).

The shaft 25 is provided with a block 22 which is slidable in the i-line direction and rotates integrally with the shaft 25 in a manner similar to that shown in FIG.
is mounted and the block is biased towards the gear by a spring 23.

A protrusion 24 is formed on the gear 21, and this engages with a slope 22a formed in a recess 22' formed in the block 22, so that when the gear 21 rotates, the block 22,
The fact that the conveyance screw 17 is rotated via 825 and the toner collected in the cleaning device can be discharged from the device is exactly the same as in the device shown in FIG. Probably.

In such a device, in the illustrated device, a support plate 27 is attached to the casing, and a pin 27a provided on the support plate 27 is attached to the casing.
A bell crank member 28, which is given a clockwise rotational habit by a spring 29, is pivotally attached to the bell crank member 28, and one leg portion 28b of the bell crank member 28 is brought into contact with the block 22.

Furthermore, other pins 27b provided on the support plate 27 include
The arm 30 to which the microswitch 31 is attached is pivotally mounted, and a spring 32 gives the arm 30 the ability to rotate clockwise. The other leg portion 28a is positioned at an appropriate position below the other leg portion 28a in the drawing.

With the above structure, when the block 22 is displaced to the left in the drawing due to toner pressure, the bell crank 28 is rotated counterclockwise, and the other leg 28a is attached to the arm 30. The contact of the attached microswitch 31 will be turned on.

Therefore, this signal may be indicated by some kind of mark or message display type display at a suitable location that will easily attract the attention of the operator of the copying machine.

At this time, the on/off of the microswitch is controlled by block 2.
Since this is repeated by the reciprocating movement of 2, the above display is used to prevent malfunction.

It is also possible to carry out the process after the switch is repeatedly turned on and off for a predetermined number of times or for a predetermined period of time.

FIG. 2 shows another embodiment of the invention.

The means for driving the conveying screw are the same as those shown in the first part above.

In this device, the optical sensor 33 is attached to the support plate 27, and the rotation of the leg portion 28a of the bell crank 28 cuts the light receiving portion of the sensor, similar to the case of the aforementioned device. The amount of toner can be displayed.

FIG. 3 shows yet another embodiment of the invention.

The gear 21 on the input side is loosely fitted to the shaft 25, and the shaft 2 is connected to the shaft 25.
5, a block 33 is disposed which rotates together with this and is freely displaceable in the axial direction.

A friction pad 34 is provided between the gear 21 and the block 33.
A spring 23 is mounted on the shaft 25, and this spring biases the block 33 in the direction of the gear 21.

With this structure, when the gear 21 is driven, the torque is a! in the normal operating state. The shaft 25 is rotated through the scrubbing pad 34 and the block 33, and the conveyance screw 17 whose end is attached to the shaft is rotated to convey the toner collected in the cleaning device to the storage section inside the photoreceptor.

When the conveying screw exerts a braking action on the input side due to pressure from the toner side, slip occurs between the gear 21, the block 33, and the friction pad 34, and as the pressure on the toner side increases, Finally gear 21
becomes completely idle, and no more toner is conveyed.

Therefore, by appropriately determining the frictional action of the friction pad, it is possible to reliably prevent excess toner from being conveyed to the storage section and thereby causing the above-mentioned problems.

In the above device, a plurality of protrusions 33a, . 35b.

Therefore, when the friction pad 34 is working well, the block 33 rotates at a constant speed and signals are sent to the sensor 35 at regular intervals, but when the toner pressure increases and slipping occurs, the signal intervals change accordingly. Since the time will gradually deviate from the initial setting, appropriate measures may be taken, such as issuing an alarm or stopping the device, when a predetermined interval is reached.

As explained above, according to the present invention, when the toner storage section that receives toner in the cleaning device becomes full, toner feeding is automatically stopped, and this is detected and some means is taken. Since we have made it possible to display this, it may indicate that the toner storage section is full even though there is plenty of room, or it may not indicate this even though it is full, and excess toner may be sent to the storage section. It is possible to reliably prevent damage to the transfer material or contamination of the internal parts of the image forming apparatus.

Furthermore, in the above embodiments, an apparatus using a photoconductor as a toner storage section has been described, but the present invention is not limited to this, and can also be applied to a case where a toner container that can be taken out independently from an image forming apparatus at any time is used. Of course, the invention is applicable.

Furthermore, in each of the above embodiments, a case has been described in which the means for nullifying the torque on the input side is formed on the shaft that directly supports the conveying screw. It will be readily understood that it can be disposed in a portion upstream of 21.

Furthermore, in the above embodiments, the case where the present invention is applied to a copying machine has been described, but the present invention is not limited to this and can easily be applied to other image forming apparatuses. That would be understandable.

(3) Effects of the Invention Since the present invention has the configuration described above, when collecting used toner, it is possible to detect whether the collecting section is full regardless of whether it is full or vice versa. We will definitely prevent situations where the system is not instructed even when it is full.
This can prevent troublesome maintenance, damage to equipment, and contamination.

[Brief explanation of the drawing]

FIG. 1 is a side view of essential parts showing an embodiment in which the present invention is applied to a copying machine, FIGS. 2 and 3 are side views of essential parts showing other embodiments of the present invention, and FIG. FIGS. 5 and 6 are a side view showing the configuration of the main parts of a copying machine suitable for this application. FIGS. 5 and 6 are a plan view and a side view, respectively, showing the configuration of the toner collection and detection portions. 11φ... Cartridge, 12... Photoreceptor, 13φφ
- Developing device, 14...Cleaning device, 17. Conveying screw, 18... Pipe, 21--., 22.
33...Block, 23...e spring, 28・φ・bell crank, 31・fist・micro switch, 33.35φ
Fist/light detection sensor. Figure 1 Figure 2 Figure 5 Figure 6

Claims (1)

[Claims] In a cleaning device configured to discharge toner collected from the surface of an image carrier to the outside by a conveyance screw, a drive unit that drives the conveyance screw is configured to set a load on the conveyance screw to a predetermined value. It is characterized by being provided with a means for cutting off the drive to the conveying screw when it exceeds the limit, a means for detecting that the drive to the conveying screw has been cut off, and a means for outputting a signal to display the detection result. cleaning equipment.