JP2751299B2 - Image forming apparatus blade cleaning device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for cleaning the surface of an image bearing member such as a photosensitive drum in an electrophotographic image forming apparatus, and more particularly, to a photosensitive drum. The present invention relates to an apparatus for preventing the blade from being pressed on the toner scraped by the blade when the blade is stopped.

(Prior Art) In an image forming apparatus using a xerography method, such as an electronic copying machine or a printer, a toner image is formed on an image carrier such as a photosensitive drum and the toner image is transferred to paper. By doing so, it is configured as a device that creates recording paper.

In the image forming apparatus as described above, in order to form a toner image on the surface of the photoconductor drum, the surface of the photoconductor drum is uniformly charged, and optical information from an image reading device, a writing device, or the like is used. A step of irradiating the surface of the photoconductor drum to form an electrostatic latent image and supplying and attaching toner from a developing device to the electrostatic latent image formed on the photoconductor drum as a toner image The process is performed through a process of forming a visible image and a process of transferring the toner image to a sheet by discharging a corotron or the like.

Then, after the toner image is transferred to the paper, the toner remaining on the surface of the photosensitive drum is cleaned by a cleaning device disposed downstream in the rotation direction of the photosensitive drum, and the next image forming operation is performed. To be able to deal with.

As a cleaning device for cleaning the image carrier as described above, a blade cleaning device is generally used. This blade cleaning device
By pressing the blade with a uniform pressure in the width direction of the photoconductor drum and rotating the photoconductor drum, the toner remaining on the surface thereof can be scraped off.

However, in a general blade cleaning device, as the number of recording papers formed increases, a mixture of paper dust and toner from the paper accumulates at the leading end of the blade, which hinders the cleaning function of the blade. May occur.

When the lump of toner adheres to the tip of the blade and solidifies, the cleaning function of the blade is reduced, the toner remains on the surface of the photosensitive drum, and streak-like dirt occurs on the copy. Problem arises.

Further, even when the operation of the image forming apparatus is stopped, as described above, the lump of toner deposited on the tip of the blade remains in a state in which the blade is pressed against the surface of the photosensitive drum by the blade as it is. If the lump of toner is left while being strongly pressed, problems such as scratching the surface of the photosensitive drum occur.

Therefore, in the conventional blade cleaning device, for example, as shown in Japanese Patent Application Laid-Open No. 60-166472, when one process of making a copy is completed,
Immediately before the rotation of the photosensitive drum is stopped, it is proposed that the blade be retracted to release the pressing state on the photosensitive drum.

As described above, there is an example in which the operation of retracting the blade is performed after the photosensitive drum is stopped, as disclosed in Japanese Patent Application Laid-Open No. 54-147047.

An apparatus such as disclosed in Japanese Patent Application Laid-Open No. 60-49381 is also known in which the photoconductor drum is slightly rotated in the reverse direction after the process to remove the lump of toner attached to the tip of the blade. is there.

(Problems to be Solved by the Invention) However, in the apparatus provided with the conventional blade retraction mechanism as described above, for example, the blade is retracted immediately before the rotation of the photosensitive drum stops. In this case, the residual toner and paper dust adhering to the photoconductor drum have a portion that remains without being cleaned.

Then, since the remaining toner and the like are transferred to the next copy, there is a problem that the first copy of the process is stained, and further, the toner remaining on the surface of the photosensitive drum is removed. The rotation of the photosensitive drum scatters the surroundings, thereby easily causing a problem such as soiling the apparatus around the charging corotron or the optical system.

When a method is used in which the blade is retracted while the rotation of the photoconductor drum is stopped, when the blade is returned, the toner mass adhering to the surface of the photoconductor drum is removed. This causes the problem that the mass of the toner is strongly pressed against the surface.

Further, it is necessary to slightly reverse the photoconductor drum so as to remove the lump of toner attached to the blade,
Although it is relatively good in that it can exert the cleaning effect on the tip of the blade, reversing the photoconductor drum generates a large frictional force between the blade and the surface of the photoconductor drum. There is a problem such as shortening.

On the other hand, as shown in JP-A-60-178478, it is possible to retract the blade and rotate the photosensitive drum slightly in the opposite direction until the blade is pressed again. Proposed.

However, in the apparatus of the related art, during the operation of making a copy of one process, the blade is pressed against the photosensitive drum while the solenoid is energized, and the solenoid is turned off. In the meantime, it is configured to perform an operation of rotating the photosensitive drum in the reverse direction. Therefore, while the operation of making a copy is being performed, the solenoid is in an energized state.
In the case where a large number of copies are continuously made from the viewpoint of the performance of the solenoid, inconveniences such as overheating of the solenoid are likely to occur.

Further, in the blade cleaning device as shown in the conventional example, since the blade is retracted after the rotation of the photosensitive drum is stopped, the distance between the stop of the photosensitive drum and the retraction of the blade is long. In such a case, there is a possibility that a problem such as pressing of a lump of toner against the surface of the photoreceptor drum by a blade and fusing the same is caused.

(Object of the Invention) The present invention solves the above-mentioned disadvantages of the conventional apparatus, and prevents the tip of the blade from pressing the scraped toner mass when the image carrier is stopped. It is an object of the present invention to provide a device that can prevent the occurrence of the influence of the residual toner mass when producing the recording paper.

(Means and Actions for Solving the Problems) The present invention removes toner remaining on the surface of an image carrier after transferring a toner image formed on an image carrier such as a photoconductor drum onto paper. Therefore, the present invention relates to an image forming apparatus provided with a blade cleaning device. In the present invention, the blade of the cleaning device is pressed against the surface of the image carrier by a biasing means such as a spring, and in accordance with an image forming process, a means for retracting by a solenoid device and a link mechanism is provided.
The driving mechanism is configured so that the image carrier can be driven in a direction opposite to that in the case of image formation, and immediately before the image carrier is stopped at the end of the image forming process, and when a new image forming process is performed. When the operation is started or when the image forming process is restarted, when performing the operation of reversely driving the image carrier, the retracting means of each of the blades is operated for a predetermined time, and the blade is imaged. It is characterized in that an operation of separating from the carrier is performed.

Therefore, while the photoconductor is stopped, inconveniences such as pressing the mass of toner accumulated between the tip of the blade and the photoconductor by the blade and fusing the mass of toner occur. And damage to the blade and the photoconductor can be prevented.

Further, in the device of the present invention, since the solenoid is operated only for a relatively short time for retracting the blade, it is possible to prevent the solenoid from generating heat and the like and not to consume extra current. The benefits can be demonstrated.

(Embodiment) The configuration of the blade cleaning device of the image forming apparatus of the present invention will be described with reference to the illustrated example.

In the cleaning device 10 of the present invention shown in FIG. 1, an opening is formed in a portion of the housing 11 facing the photosensitive drum 1, and the blade 20 is pressed against the surface of the photosensitive drum 1 from the opening. It is provided in. The blade
20 is a plate-like member made of polyurethane rubber or the like, similarly to a conventionally used blade,
It is detachably attached to the blade holder 21.

The blade holder 21 that holds the blade 20 is attached to a lower bracket 22 that is swingably provided with respect to a support shaft 23, and the lower bracket 22 projects through a stud 26 that is provided to protrude to the rear. By being swung, an operation of pressing the blade holder 20 against the photosensitive drum 1 and an operation of separating the blade holder 20 from the photosensitive drum 1 are performed. In addition, the photosensitive drum 1 as an image carrier of the present invention
The mechanism for driving the photosensitive drum is configured so that the photosensitive drum can be driven forward and backward. When the image is formed, the photosensitive drum is driven in the reverse direction by retracting the blade. Is performed according to a program set in the control device.

On the back plate 12 of the housing 11 of the cleaning device,
A stud 26 for swinging the blade has a hole formed therethrough, and a spring 31 on the outside of the back plate 12,
A link device 25, a solenoid 30 for driving the link device, and the like are arranged.

Further, inside the housing 11, as described above, the blade 20 and the blade holder 21, and an auger for carrying the scraped toner out of the housing.
14 and a flicker bar 15 for dropping toner staying inside the housing to a lower portion are provided. Each of these devices is connected to a drive mechanism (not shown) to perform a predetermined operation.

Further, a brush 13 as an upper seal member is provided in an upper portion of the opening of the housing 11, and a lower seal such as a film is disposed in a lower portion. The toner cloud is prevented from leaking from between the body drum.

Blade cleaning device configured as described above
In 10, when the photosensitive drum 1 is driven to form a recording sheet, the stud 26 is urged upward by the spring 31. Therefore, after the tip of the blade 20 is pressed against the surface of the photosensitive drum 1 to transfer a toner image to a sheet, an operation for removing toner and the like remaining on the surface of the photosensitive drum is performed.

Then, when one process of making the recording paper is completed, the solenoid 30 is driven as described later, and the stud 26 is lowered via the link mechanism 25 to move the blade 20 away from the photosensitive drum. Do.

Next, in the blade cleaning device configured as described above, in relation to the process of creating the recording paper,
Control of the swinging operation of the blade and control of the rotation of the photosensitive drum will be described with reference to FIGS. 2 and 3.

2 and 3 show the relationship between the rotation direction of the photosensitive drum 1 and the operation of retracting the blade 20. FIG.

First, during the process of forming the recording paper, as shown in FIG. 2A, the photosensitive drum 1 is driven in the counterclockwise direction (positive direction) in FIG. The blade 20 is pressed to remove the toner remaining on the surface of the photosensitive drum after the transfer of the toner image.

Therefore, during the cleaning operation as described above, the lump of the toner t is accumulated at the lower end portion of the blade 20 and the lump of the toner is dropped at any time or the lump of the toner is fixed. As it grows in size, it falls to the bottom of the housing.

As described above, when the process of preparing the recording paper is completed and the signal is input, the solenoid is energized by a command from the control device, and as shown in FIG. Since the blade 21 is swung, the blade 20 is separated from the surface of the photosensitive drum 1, but the photosensitive drum is driven for a certain period thereafter.

Then, when the photosensitive drum 1 is stopped and the blade 20 is returned to a state where the blade 20 is pressed again by the photosensitive drum, as shown in FIG. Stop at a position downstream from the position where the movement is performed.

When the next process is restarted from the state where the photosensitive drum 1 is stopped, the rotation of the photosensitive drum and the swinging operation of the blade are performed in the order shown in FIG. Done. That is, when the next process is restarted, first, the photosensitive drum 1 is driven in the forward direction as shown in FIGS. The blade 20 is separated, and then the blade 20 is retracted.

Thereafter, as shown in FIG. 4C, the photosensitive drum 1 is driven in the reverse rotation direction, and is moved upstream from the position where the toner mass t is pressed by the blade. Then, the process of creating the next recording paper is started from the state shown in FIG.

The operations of controlling the rotation of the photosensitive drum and controlling the swing of the blade as described above are performed as shown in the timing chart of FIG. In the above-described embodiment, the diameter of the photosensitive drum is
Use a 150mm one and the rotation speed (peripheral speed) is 100mm / sec
The example in the case of is shown.

That is, when the start button of the image forming apparatus is first depressed at the time of forming the recording paper, the photosensitive drum is driven in the normal rotation direction for a predetermined time (300 msec), and the blade is retracted on the way. The operation of retracting the blade is performed for 1100 msec. After the photosensitive drum is rotated forward for a certain period of time and then driven in the reverse direction for 700 msec, as shown in FIG. In this way, the mass of toner is set at a position downstream of the position where the blade contacts the photosensitive drum. Thereafter, the photosensitive drum is driven in the normal rotation direction, and an operation of pressing the blade against the photosensitive drum is performed. In this state, the operation of forming the recording paper is continued.

Then, the blade is retracted after a predetermined time T has elapsed since the signal for detecting the trailing end portion P of the last sheet is input to the control device, after the operation for forming the last recording sheet of the process is completed. . After that, the drive of the photosensitive drum in the normal rotation direction is stopped, and then the operation of retracting the blade is ended, and the job of creating the recording paper is ended.

The above-described operation is performed each time a recording paper creation command is input to the image forming apparatus. For one recording paper creation process, the first and last operations of the command are performed. Then, the control is performed in accordance with the programs set in the control device.

In the blade cleaning device of the present invention, a device for retracting the blade is provided at the rear portion of the housing as shown in FIG. In the embodiment shown in FIG. 5, a stud 26 provided at the rear of the blade holder is attached to a lever 27, and one end of the lever 27 is connected to a fulcrum 27a.
It is supported by the back plate 12 of the housing.

The lever 27 is provided with a plurality of springs 31. The springs urge the studs 26 upward, thereby performing an operation of pressing the blade against the photosensitive drum. A solenoid 30 and a link device 28 are provided to oppose each other. Then, when the blade is retracted, the solenoid 30 is energized to perform an operation of pulling down the lever 27 via the link device 25. When the collected toner is discharged from the housing by the auger, the toner discharge pipe
Use 17 to guide to the toner recovery device.

The blade cleaning device having the above-described configuration includes:
The present invention can be applied to an image forming apparatus as shown in FIG. The image forming apparatus shown in FIG. 6 is connected to a computer or the like and is configured as an apparatus for producing a recording sheet. A writing device 35 is provided around the photosensitive drum 1, Developing device 36, pre-transfer corotron
37, in addition to the transfer / peeling corotron 38 and the blade cleaning device 10, in addition to the peeling claw 42, the eraser 43, the charge corotron 45, and the like, a thermistor 44 for detecting the surface temperature of the photosensitive drum is disposed. I have. In addition, an introduction path 40 is disposed on the upstream side of the paper transport path that passes through the image transfer portion by the transfer / peeling corotron 38, and a transport belt device 41 and the like are disposed on the downstream side. The device is arranged.

And, by the discharge by the charge corotron 45,
After uniformly charging the surface of the photoconductor drum, light from a light emitting unit such as an LED provided in the writing device 35 is irradiated on the photoconductor drum to form an electrostatic latent image on the surface of the photoconductor drum, Toner is attached to the electrostatic latent image by a developing roller 36a of a developing device 36, and is visualized as a toner image.

After that, the toner image is transferred to the sheet by the discharge from the transfer / peeling corotron 38, and the sheet is peeled from the photosensitive drum together with the action of the peeling claw 42 to remove the sheet carrying the unfixed toner image. The sheet is transported toward the fixing device.

After the toner image is transferred to the paper, the toner remaining on the surface of the photosensitive drum is cleaned by a cleaning device, and is uniformly charged by the eraser 43 and the charge corotron. To be able to correspond to the formation.

Note that the blade cleaning device of the present invention as described above is not used only for an image forming apparatus as shown in the embodiment, but is a general xerographic apparatus such as an electronic copier or a laser printer. It can be used for various devices.

Further, the blade retracting mechanism and the control of the rotation of the photosensitive drum of the present invention are configured in accordance with the characteristics of the image forming apparatus, and are particularly limited to those described in the embodiments. Not something.

(Effect of the Invention) Since the blade cleaning device of the image forming apparatus of the present invention has the above-described configuration, the mechanism for retracting the blade can be simplified, and only when the blade is retracted, Since the solenoid is operated for a short time, there is no problem such as heating of the solenoid, and the stability of the device can be improved.

In the cleaning device of the present invention, while the photoconductor is stopped, the mass of toner accumulated between the tip of the blade and the photoconductor is pressed by the blade to melt the mass of toner. It is possible to prevent inconveniences such as wearing, and prevent the blade and the photoconductor from being damaged.

Further, in the device of the present invention, since the solenoid is operated only for a relatively short time for retracting the blade, it is possible to prevent the heat generation of the solenoid and the like, and not to consume an extra current. It is possible to demonstrate.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the cleaning device of the present invention, and FIG. 2 shows the state of a photosensitive drum and a blade at the end of a recording paper forming process. FIG. 3 is an explanatory view showing a state of a body drum and a blade, FIG. 3 is an explanatory view at the start of a process, and FIGS. 3A to 3D are explanatory views showing states of a photosensitive drum and a blade, respectively; 4 is a timing chart showing the state of control of the operation of the apparatus of the present invention, FIG. 5 is a view of the housing of the blade cleaning apparatus viewed from the back, and FIG. 6 is applicable to the blade cleaning apparatus of the present invention. FIG. 3 is an explanatory diagram illustrating an example of an image forming apparatus. Reference numerals 1 in the drawing: photoreceptor drum, 10: blade cleaning device, 20: blade, 21: blade holder, 23:
Support shaft, 25 Link device, 26 Stud, 27 Lever, 28 Retract mechanism, 30 Solenoid, 31
… Spring, 35… writing device, 36… developing device, 45
...... Charge corotron.

Claims (1)

(57) [Claims] An image formed by transferring a toner image formed on an image carrier such as a photosensitive drum to a sheet of paper, and then providing a blade cleaning device to remove toner remaining on the surface of the image carrier. In the forming apparatus, a means for pressing the blade of the cleaning device against the surface of the image carrier by a biasing means such as a spring and retracting the same by a solenoid device and a link mechanism in accordance with an image forming process is provided. The driving mechanism is configured so that the carrier can be driven in a direction opposite to the direction of image formation, and immediately before stopping the image carrier at the end of the image forming process, and the operation of a new image forming process. When the image carrier is driven to rotate in the reverse direction when starting image forming or when restarting the image forming process. Retraction means de actuates predetermined time, blade cleaning device of the image forming apparatus characterized by causing the operation of separating the blade from the image bearing member.