JPH1115346A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a cleaning blade from being warped at the time of starting operation of an image carrier in an image forming device and form an image with excellent quality. SOLUTION: At the time of steady rotation of a photoreceptor drum 1, a second driving means 18 drives a transporting means 10 to transport the remaining substance as a waste toner which is removed from the image carrier 1 by a cleaning blade 9 toward a prescribed position in a recovery part. On the other hand, at the time besides the steady rotation of the photoreceptor drum 1, the second driving means 18 is driven in the reverse direction to the driving direction at the time of steady cleaning to inversely transport the waste toner which is being transported toward the prescribed position by the transporting means 10 to the image carrier 1 side and supply the toner to the surface of the image carrier 1.

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 having a cleaning device for forming an image by transferring a visible image on an image carrier onto a transfer material, and cleaning the transferred surface with a cleaning blade. Further, the present invention relates to driving of an image carrier such as a photoreceptor and a dielectric, and is used for a copying machine, a printer, a facsimile, a composite device thereof, and the like.

[0002]

2. Description of the Related Art In the field of a conventional image forming apparatus, as disclosed in Japanese Utility Model Laid-Open No. 01-118880,
There has been proposed an apparatus that detects the rotation torque of a photoconductor and stops the photoconductor when the torque is large.

According to this, when the friction between the cleaning blade and the surface of the photosensitive member increases, the photosensitive member is stopped by an increase in torque, so that the turning of the cleaning blade can be prevented.

[0004]

However, the prevention of the blade turning of the conventional image forming apparatus does not reduce the state where the friction between the photosensitive member and the cleaning blade is increased.

[0005] Therefore, even if the increase in friction is effective at times such as temperature and humidity, or when it is resolved by the passage of time, it is effective when the surface of the photosensitive drum is mirror-finished. There is a problem that the blade turning cannot be prevented when driving is started next time.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of forming a good image by preventing the cleaning blade from being turned up at the start of driving the image carrier.

[0007]

According to another aspect of the present invention, there is provided an image forming apparatus comprising: an image carrier; a first driving unit for driving the image carrier; Latent image forming means for forming a latent image on the body, developing means for developing the latent image on the image carrier to a visible image, transfer means for transferring the visible image on the image carrier to a transfer material, Cleaning means having at least a cleaning blade for removing a residue remaining on the surface after transferring the visible image from the image carrier.
The latent image formed by the latent image forming means on the image carrier driven by the driving means is developed by the developing means, the developed visual image is transferred to the transfer material by the transfer means, and the residual surface on the transferred surface is transferred. The object is cleaned and removed by the cleaning blade of the cleaning unit, the second driving unit stops, and the image formation ends.

[0010] The invention according to claim 1 further comprises a transporting means for transporting the removed residue, and a second driving means for driving the transporting means. The second driving means is driven in a direction opposite to the rotation direction during normal cleaning.

In such a configuration, in the image formation, the transporting means is driven by the second driving means, and the residue removed from the image carrier by the cleaning means is transported to a predetermined position such as a collecting section thereof. However, other than during the normal rotation of the image carrier, the second driving unit is driven in a direction opposite to the driving direction at the time of the cleaning, and the transporting unit conveys the residue that has been conveyed toward a predetermined position. Since it can be conveyed backward to the body side and supplied to the surface of the image carrier, this acts as a lubricant between the image carrier and the cleaning blade at the start of driving of the image carrier in the next image formation to reduce friction between the two. Further, it is possible to prevent the cleaning blade from being turned up at the start of driving the image carrier.

According to a second aspect of the present invention, there is provided a transport unit for transporting the removed residue, a second driving unit for driving the transport unit, and a detecting unit for detecting a surface state of the image carrier. The image forming apparatus further includes a second driving unit that is driven in a direction opposite to a rotation direction during normal cleaning, other than during the normal rotation of the image carrier, according to a detection result of the detection unit. Things.

In such a configuration, the conveying means is driven by the second driving means to convey the residue removed from the image carrier by the cleaning means to a predetermined position such as a collecting section thereof, and the detecting means is provided. The surface state of the image carrier to be detected is detected, but other than during the steady rotation of the image carrier, the second driving unit is driven in a direction opposite to the driving direction at the time of the cleaning, and the conveying unit is moved to a predetermined position. The residue transported toward the image carrier is reversely transported to the image carrier side and supplied to the surface of the image carrier, and this is used as a lubricant between the cleaning blade and the image carrier at the start of driving the image carrier in the next image formation. It is possible to reduce the friction between the two by working, and to prevent the cleaning blade from being turned up at the start of driving of the image carrier, by the minimum necessary operation according to the detection result.

[0012]

As described above, according to the first and second aspects of the present invention, the once removed residue is again supplied to the image carrier and the cleaning blade without affecting the normal image formation, and the next image formation is performed. At the start of driving of the image carrier, the friction between the image carrier and the cleaning blade is reduced to prevent the blade from being turned up and to form a good image.

According to the second aspect of the present invention, it is possible to particularly prevent the blade from being turned up with a minimum necessary operation.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical embodiment of the present invention will be described below with reference to the accompanying drawings.

The present embodiment is an example of an image forming mechanism common to image forming apparatuses such as a copying machine, a facsimile, a printer, and a multifunction machine for forming an image by an electrophotographic method. As shown in FIG. 2, a photosensitive drum 1 is used as an image carrier. A charging device 2 for uniformly charging the photosensitive drum 1 to a negative polarity or a positive polarity around the photosensitive drum 1, and irradiating the charged photosensitive drum 1 with a recording light image 3 to perform image exposure. , An image exposure device 3a for forming an electrostatic latent image corresponding to an original or an image signal, and applying charged colored particles, for example, toner, to the electrostatic latent image formed on the photosensitive drum 1 to visualize the image. Developing device 4, a transfer device 5 for transferring the visualized toner image on the photosensitive drum 1 to a transferred transfer material 16, and a separating device for separating the transferred transfer material 16 from the photosensitive drum 1 6. A cleaning device 7 for cleaning particles remaining on the surface of the photosensitive drum 1 after transfer material separation, that is, residual toner, and removing the toner from the surface of the photosensitive drum 1, and removing charges remaining on the photosensitive drum 1 Discharging device 8 are sequentially disposed along the rotation direction of the photosensitive drum 1 for.

As the photoconductor drum 1, an organic photoconductor is used. In addition, an inorganic photoconductor such as a selenium arsenic photoconductor, a selenium tellurium photoconductor, a CdS photoconductor, and an amorphous silicon photoconductor can be used. In short, the mechanism for supporting the particles forming the image, the transferred particle image to the transfer material 16
Various image carriers can be employed according to the type of mechanism for transferring the image to the image carrier. A belt-shaped one instead of a drum-shaped one can also be used.

The charging device 2 includes a charge wire 2a
Type that discharges by applying a high voltage to, but in addition to this, charging roller, charging brush, charging sheet,
Needle electrodes and the like can also be used.

As the transfer device 5, a discharge type device using a charge wire 5a is used as in the case of the charging device 2, but a transfer roller, a needle electrode, a transfer drum, a transfer belt, or the like can also be used. .

The separation device 6 includes a charge wire 6a
Although a type that neutralizes and removes the charge added to the transfer material by mainly applying an AC voltage is used, a separation claw or a separation belt can be used. Further, when the diameter of the photosensitive drum 1 is small or the like, the separation can be performed by the stiffness of the transfer material 16.
Is not required.

As a first embodiment of the cleaning device 7, a cleaning blade 9 made of polyurethane rubber as shown in FIGS.
A roll-shaped brush 10 rotatably supported near the contact portion of the cleaning blade 9 with the photosensitive drum 1 on the upstream side in the rotation direction of the cleaning blade 9. Brush 10
The cleaning blade 9 forms a transport means for cleaning the residue remaining on the surface of the photosensitive drum 1 by removing the residue remaining on the surface of the photosensitive drum 1 and scraping the residue to a collection path 13 having a collection screw 12. The collected residue is collected by a collecting unit (not shown) in cooperation with the above. The cleaning blade 9 is pivotally supported by the main body of the cleaning device 7 so as to be able to swing about a swing fulcrum shaft 14.
Is pressed against the surface of the photosensitive drum 1 in the counter direction with respect to the rotation direction of the photosensitive drum 1. Further, as a material of the brush 10, rayon-based, acrylic-based, nylon-based, other synthetic fibers, metal fibers, or the like can be used, and the conductivity and the insulating property are not particularly limited. Further, as shown in FIG. 2, there is a method of applying a voltage from a DC power supply 11 or the like to the shaft 10a of the brush 10 or grounding the brush 10 to adjust the function of transporting the charged toner and the residue. This is not particularly limited. Also, the cleaning blade 9
As a material for the other materials, silicon-based rubber or fluorine-based rubber may be used. Also, the cleaning device 7
May be a combination with another cleaning means as long as there is a cleaning blade 9 and a conveyance means of the residue. The brush 10 and the collecting screw 1 are used for conveying the residue.
A configuration other than the combination with the configuration 2 may be used.

In the first embodiment of the cleaning device 7 shown in FIG. 2 in this embodiment, a conductive acrylic fiber is used as the brush 10, the wire diameter is 6.2D (denier), and the brush is Density is 10,000 lines / inch ² Line length is 4
mm, and the number of rotations during normal rotation when the photosensitive drum 1 is rotated at a regular speed to form an image is 150 r.
pm, the cut-in allowance for the photosensitive drum 1 is 1.0 m
m, and a voltage having a polarity opposite to that of the toner is applied to the brush shaft 10a. In the first embodiment, since a positive polarity toner is used, a negative polarity voltage is applied to increase the toner and residue transport force.

The brush 10 is driven by a motor 16 or the like. The driving direction is the direction of rotation of the photosensitive drum 1 as shown by an arrow in FIG. In the same direction as brush 1
The traveling direction is set to be opposite to each other at a contact portion between the photoconductor drum 1 and the photosensitive drum 1 (hereinafter, this rotation is referred to as a counter rotation).

In this way, at the time of image formation, while collecting waste toner which is a residue such as toner removed from the photosensitive drum 1 by the cleaning blade 9 of the cleaning device 7, the waste toner is conveyed to the collection path 13 side to be scraped with the scraper 17. The collection path 13 is scraped off by the cooperation of the above, and the collection screw 12 conveys it to a collection unit (not shown).

In this embodiment, the motor 16 is driven in a direction opposite to the driving direction during the normal cleaning, and the brush 10 is conveyed toward the collection path 13 while being stored, except during the normal rotation of the photosensitive drum 1. The waste toner scraped to the recovery path 13 is conveyed from the recovery path 13 side to the photosensitive drum 1 side and supplied to the surface of the photosensitive drum 1 in advance. The supplied waste toner acts as a lubricant with the cleaning blade 9 at the start of driving of the photosensitive drum 1 in the next image formation to reduce friction between the two, and when the driving of the photosensitive drum 1 is started. The turning of the cleaning blade 9 can be prevented, and a good image can be formed.

The timing chart of FIG. 3 shows an example of such an operation control in the first embodiment of the present embodiment. To explain this, the rotation of the photosensitive drum 1 is started by an image formation start signal by operating a start key or the like, but it takes time T ₀ until the photosensitive drum 1 reaches a steady speed. From the start signal until the photosensitive drum 1 starts rotating, or
Starts rotating, and at the same time, the brush 10 is also rotated. The rotation direction of the brush 10 at this time is set in the opposite direction to that during the normal cleaning (hereinafter, this rotation is referred to as whis rotation). Due to the rotation of the brush 10, the waste toner accumulated in the brush 10 during normal cleaning is reversely conveyed from the recovery path 13 side to the photosensitive drum 1 side and sent between the photosensitive drum 1 and the edge of the cleaning blade 9. be able to.

When the photosensitive drum 1 is rotated at a regular speed, a cleaning device 7 for forming the first image is formed.
Usually needs to exert a cleaning function.
To the counter rotation. It is preferable that the timing of the transition be before or after the photosensitive drum 1 has reached the steady rotation, without any excessive or insufficient timing.

The timing for supplying the waste toner by the rotation of the brush 10 is not limited to the start of the operation of the photosensitive drum 1. For example, the rotation may be performed after the steady rotation before the rotation of the photosensitive drum 1 is stopped. When the waste toner is supplied between the photosensitive drum 1 and the cleaning blade 9, the next image formation is performed. When the photosensitive drum 1 starts to be driven, the turning of the cleaning blade 9 can be similarly prevented.

The second embodiment of the cleaning device 7 of the present embodiment
FIG. 4 shows an embodiment of the present invention. To explain this, the basic configuration is the same as that of the first embodiment shown in FIGS. 1 and 2, but the rotation direction of the photosensitive drum 1 at the contact portion of the cleaning blade 9 with the photosensitive drum 1 A paddle 111 is provided in the vicinity of the upstream side, and waste toner which is a residue such as toner scraped off from the surface of the photosensitive drum 1 by the cleaning blade 9 by the counter rotation of the paddle 111 is disposed in a rear collecting container provided in the cleaning device 7. It is designed to be scraped and collected in 112. Then, by rotating the paddle 11 with the unsteady rotation at the same timing as described in the first embodiment of the photosensitive drum 1, the waste toner on the photosensitive drum 1 side is reversely conveyed from the collection container 112 side. Is supplied to the surface of the photosensitive drum 1,
When the next driving of the photosensitive drum 1 is started, the lubricant becomes a lubricant to reduce the friction between the cleaning blade 9 and the photosensitive drum 1, thereby preventing the cleaning blade 9 from being turned up. It is to be noted that the paddle 111 is not limited to the paddle 111. Instead of the paddle 111, for example, various types of rollers can be used.

In addition to the above, a method of switching the polarity of the voltage applied to the brush 10 or the like to a polarity opposite to the polarity at the time of normal cleaning so that the gripped waste toner can be supplied to the surface of the photosensitive drum 1. There is also. If the switching of the voltage polarity and the switching of the driving direction described above are performed in combination, the efficiency of supplying waste toner to the photosensitive drum 1 can be increased, and the time required for such an operation can be reduced. There are advantages mentioned.

As a method of switching the rotation method, a method of switching the polarity of the drive voltage of the DC motor 18 for driving the brush 10 or the paddle 111 is generally used. But,
Although not shown, an electromagnetic clutch (not shown) is provided between the brush shaft 10a and the drive shaft to rotate the brush 10 using a motor shaft and a shaft interlocked with the photosensitive drum 1 as a drive shaft. The rotation can be performed by forcibly driving the electromagnetic clutch by setting the electromagnetic clutch to a connected state, and the rotation of the brush can be performed by setting the electromagnetic clutch to a disconnected state so that the brush 10 is rotated by contact friction with the photosensitive drum 1. .

As shown in FIG. 1 of the first embodiment and FIG. 4 of the second embodiment, a motor drive control 19 for driving the DC motor 18 and the like When the drum 1 is rotated at a time other than the normal rotation, the rotation of the drum 1 is performed in accordance with the detection result of the various detecting means 20 for detecting the surface state of the photosensitive drum 1. The waste toner is supplied only when the cleaning blade is turned up, and the turning-up of the cleaning blade 9 at the start of driving of the photosensitive drum 1 can be prevented with a minimum necessary operation.

The various detecting means 20 detects at least one of various image forming states which causes the friction between the cleaning blade 9 and the photosensitive drum 1 to increase. Is preferred. Specifically, the driving torque of the photosensitive drum 1 is detected. Alternatively, the specularity of the surface of the photosensitive drum 1 is detected. Alternatively, the number of image resistant images and the image resistant time are detected. Alternatively, the temperature and humidity around the photosensitive drum 1 are detected.
Alternatively, a steady rotation number of the photosensitive drum 1 is detected. For example, a substitute value that can determine a situation where the cleaning blade 9 is easily turned up is detected. Various detection means 20
May be adopted according to the detection target, and the same sensor may be shared depending on the detection item, such as performing the image density detection and the specularity detection at the same time by sharing the same photo sensor. it can.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of an image forming apparatus showing a representative embodiment of the present invention.

FIG. 2 is a configuration diagram of a cleaning device that is a first embodiment of the device of FIG. 1;

FIG. 3 is a time chart of the first embodiment showing an example of brush drive direction switching between the photosensitive drum of the apparatus of FIG. 1 during steady rotation and unsteady rotation.

FIG. 4 is a configuration diagram of a cleaning device according to a second example of the present embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor drum 2 charging device 3 a image exposure device 4 developing device 5 transfer device 7 cleaning device 9 cleaning blade 10 brush 13 recovery path 16 transfer material 18 motor 19 motor drive control unit 20 various detection means

Claims (2)

[Claims] An image carrier; first driving means for driving the image carrier; latent image forming means for forming a latent image on the image carrier; and developing the latent image on the image carrier. Developing means for forming a visible image, transfer means for transferring the visible image on the image carrier to a transfer material, and at least a cleaning blade for removing a residue remaining on the surface after transferring the visible image from the image carrier. A cleaning unit having the cleaning unit, a transporting unit for transporting the removed residue, and a second driving unit for driving the transporting unit. The image forming apparatus is driven in a direction opposite to a rotation direction during normal cleaning. 2. An image carrier, first driving means for driving the image carrier, latent image forming means for forming a latent image on the image carrier, and developing the latent image on the image carrier. Developing means for forming a visible image, transfer means for transferring the visible image on the image carrier to a transfer material, and at least a cleaning blade for removing a residue remaining on the surface after transferring the visible image from the image carrier. A cleaning unit having the cleaning unit, a transporting unit for transporting the removed residue, a second driving unit for driving the transporting unit, and a detecting unit for detecting a surface state of the image carrier. An image forming apparatus characterized in that the second driving means is driven in a direction opposite to the rotation direction during normal cleaning, in addition to the normal rotation of the image carrier, in accordance with the detection result of (1).