JPH10319809A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the consumption of toner, to prevent the rolling up of a cleaning blade, at the time of starting the rotation of an image carrier and to form an excellent image by forming a toner pattern on the image carrier, after the image is formed and before a driving means is stopped. SOLUTION: The toner pattern is formed on a photoreceptor drum, after the image is formed and a motor 21 is stopped. For the fact, a toner pattern forming means 25 making use of an internal control function in a CPU 22 is used. The toner pattern forming means 25 forms the toner pattern by the operations of an electrifier 2, an image exposure device 3a and a developing device 4, after the completion of the formation of the image and before the control timing of stopping the motor 21. The toner pattern is moved by the rotation up to the stop of driving by the motor 21, of the photoreceptor drum. But, the formation of the image is completed and then, a transfer device 5 and a separating device 6 stop operating, so that reaching the contact part of the cleaning blade with the photoreceptor drum is attained without the influence of the devices 5 and 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a cleaning means having a cleaning blade for transferring a visible image on a driven image carrier onto a transfer material to form an image and cleaning the transferred surface. The present invention relates to an image forming apparatus, 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 A cleaning blade is made of an elastic member such as urethane rubber so as not to damage the surface of an image carrier. It can be firmly contacted from the counter direction. As a result, the edge of the cleaning blade formed with high precision adheres well to the image carrier, and the toner remaining on the image carrier can be sufficiently scraped off.

On the other hand, a cleaning blade exhibiting a sufficient cleaning effect, in particular, also functions to change the surface state of the image carrier at the same time as scraping off residual toner, so that a courageous photosensitive member which is initially in a mirror-finished state is removed. Is gradually roughened, and is gradually mirror-finished with respect to the inorganic photoreceptor which is initially in a roughened state or has been subjected to a roughening treatment. When the image carrier is in a mirror state, the tip of the cleaning blade that is in close contact with the image carrier surface adheres to the mirrored image carrier surface, and tends to be carried by the rotation of the image carrier. It may be turned over, making cleaning impossible or the cleaning blade itself damaged and unusable.

Japanese Unexamined Patent Publication No. Hei 6-318019 discloses a technique for solving such a problem, in which a mirror surface of a photoreceptor is detected, and a toner image is formed on one surface of a non-image portion in accordance with the detection result. A technique is disclosed in which when a cleaning blade scrapes a toner image, the surface of the photoconductor is roughened by friction caused by rubbing the entire surface of the photoconductor with toner.

[0005]

However, in the above-described conventional roughening method, toner is consumed more than necessary.

Also, when the photoconductor stops rotating,
When the cleaning blade is in close contact with the same position of the photoconductor for a long time, the photoconductor may be turned up when the next rotation is started, but this cannot be prevented by the above-mentioned conventional technology.

An object of the present invention is to reduce toner consumption and
An object of the present invention is to provide an image forming apparatus capable of preventing a cleaning blade from being turned up at the start of rotation of an image carrier and forming a good image.

[0008]

According to another aspect of the present invention, there is provided an image forming apparatus comprising: an image carrier; a driving unit configured to drive the image carrier to form an image; 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 cleaning the residue remaining on the surface after transferring the visible image of the image carrier, and after image formation,
And a toner pattern forming means for forming a toner pattern on the image carrier before the driving means stops.

In such a configuration, the image carrier is driven by the driving means, the latent image formed by the latent image forming means is developed by the developing means, and the developed visual image is transferred to the transfer material by the transferring means. Then, the residual material on the surface after the transfer is cleaned by the cleaning blade of the cleaning unit, and the image forming is completed, and the driving unit stops. Before the driving unit stops, a toner pattern is formed on the image carrier by the toner pattern forming unit, and the toner pattern is immediately transferred to the image carrier of the cleaning blade when the driving of the image carrier for the next image formation is started. It works on the contact area of the
It is possible to prevent the cleaning blade from being turned up at the start of driving of the image carrier. In addition, the toner pattern can be formed during a required time period after the image formation is completed and before the driving of the image carrier is stopped, so that the consumption of toner can be suppressed.

According to a second aspect of the present invention, in order to form a toner pattern, a toner pattern is formed on the image carrier before the driving means is stopped, in accordance with a detection result of a detection means for detecting an image forming state. The timing for forming the toner pattern is set according to the image forming state, and the next driving of the image carrier is started while the toner consumption is minimized. Occasionally, the cleaning blade can be sufficiently supplied to the contact portion of the image carrier to reduce friction between the two, and it is possible to reliably prevent the cleaning blade from being turned up.

According to a third aspect of the present invention, in any one of the first and second aspects of the present invention, the driving means is further stopped before the rear end of the toner pattern passes through the cleaning section. While the next driving of the image carrier is started, the toner pattern acts on the contact portion of the cleaning blade with the image carrier, and the toner pattern passes through the contact portion before the driving of the image carrier is stopped. To avoid having to work at the start of the next drive,
It is possible to reliably prevent the cleaning blade from being turned up.

[0012]

As described above, according to the image forming apparatus of the present invention, it is possible to form a good image by suppressing the consumption of toner and preventing the cleaning blade from being turned up at the start of driving the image carrier. it can.

[0013]

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 system. As shown in FIG. 3, 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 a visualized toner image to a transfer material 27 (not shown), a separating device 6 for separating the transferred transfer material 27 from the photosensitive drum 1, a transfer material Photoconductor drum 1 after separation
The cleaning device 7 for cleaning particles remaining on the surface of the photosensitive drum, that is, the residual toner, and the charge removing device 8 for removing charges remaining on the photosensitive drum 1
Are sequentially arranged along the rotation direction of the.

As the photosensitive drum 1, an organic photosensitive member is used. In addition, an inorganic photosensitive member such as a selenium arsenic photosensitive member, a selenium telluride photosensitive member, a CdS photosensitive member, or an amorphous silicon photosensitive member can be used. In short, a mechanism for supporting particles for forming an image, and a transfer material 27
Various image carriers can be employed according to the type of mechanism for transferring the image to the image carrier.

As the charging device 2, 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 device 6 is not particularly necessary when the separation can be performed by the stiffness of the transfer material.

As the cleaning device 7, an elastic material,
For example, a cleaning device using a single cleaning blade 9 made of polyurethane rubber is used, but if the cleaning blade 9 is present, it may be a combination with a brush or a roller. In addition, as the material of the cleaning blade 9, a silicon-based or fluorine-based rubber may be used.

As shown in FIG. 1, the cleaning device 7 is pivotally supported by the main body of the cleaning device 7 so that the cleaning blade 9 can swing about a swing fulcrum shaft 17. Is pressed against the surface of the photosensitive drum 1 in a counter direction with respect to the rotation direction of the photosensitive drum 1.

The photosensitive drum 1 is driven by a motor 21, and the charging device 2, the image exposing device 3 a, the developing device 4, the transfer device 5, the separating device 6, the cleaning device 7, and the neutralizing device 8 cooperate therewith. To form an image.
The image forming operation is controlled by, for example, a control circuit using the CPU 22 shown in FIG. 4, and starts image formation according to the set conditions and the number of documents by operating the start key 24 of the operation panel 23. Driving or operation of the drum 1 and other components is stopped according to a predetermined program. Since the specific operation is well known, the description is omitted.

When the rotation of the photosensitive drum 1 is stopped, the cleaning blade 9 comes into close contact with the same position of the photosensitive drum 1, and if this continues for a long time, the photosensitive drum 1 starts the next rotation. When it is done, it is easy to be turned up.

In order to solve this problem, in the present embodiment, after the image is formed and before the motor 21 is stopped, the photosensitive drum 1 is stopped.
A toner pattern 10 as shown in FIG. 2 is formed above.
The toner pattern 10 may be formed in any manner, but in the present embodiment, a toner pattern forming unit 25 using an internal control function of the CPU 22 is used. The toner pattern forming means 25 is provided with the motor 21 after the image formation is completed.
Before the control timing at which is stopped, the charging device 2, the image exposure device 3a, and the developing device 4 are formed to operate.
As another toner pattern forming means, the photosensitive drum 1
As long as the toner pattern 10 can be formed, any material such as a device for applying a toner pattern to the charged surface can be adopted.

Toner pattern 1 formed after image formation
0 is moved by the rotation of the photosensitive drum 1 until the driving by the motor 21 is stopped. However, since the operation of the transfer device 5 and the separation device 6 is stopped after the image formation, these movements are not affected by FIG. As shown in (2), the cleaning blade 9 can reach the contact portion with the photosensitive drum 1. When the transfer device 5 is of a contact type such as a transfer roller, a transfer drum, or a transfer belt, the transfer device 5 is separated from the photosensitive drum 1 only during the passage of the toner pattern 10 so as not to hinder the passage of the toner pattern 10. You need to do that.

The toner pattern 10 formed before the driving of the photosensitive drum 1 is stopped is replaced with the photosensitive drum 1 of the cleaning blade 9 immediately after the driving of the photosensitive drum 1 for the next image formation is started. Release material reaching the contact area,
Since the cleaning blade 9 works as an abrasive and reduces friction between the two, the photosensitive drum 1 is most likely to be turned up.
It is possible to prevent the cleaning blade 9 from being turned up at the start of the driving of. In addition, the toner pattern 10 may be formed during a necessary time after the image formation is completed and before the driving of the photosensitive drum 1 is stopped, so that toner consumption can be suppressed. If the driving of the photosensitive drum 1 is stopped before the trailing end 10-2 of the formed toner pattern 10 passes through the contact portion of the cleaning blade 9 with the photosensitive drum 1, the above-described operation and effect can be surely obtained. When the tip 10-1 of the toner pattern 10 reaches the contact portion so that the toner pattern 10 acts on the contact portion of the cleaning blade 9 with the photosensitive drum 1 at the same time as the drive of the photosensitive drum 1, the photosensitive drum 10 is exposed. The body drum 1 is preferably stopped.
Moreover, if the photosensitive drum 1 is stopped when the leading end 10-1 of the toner pattern 10 reaches the contact portion, the toner of the toner pattern 10 is not used for preventing the blade from turning up when the photosensitive drum 1 starts driving. Can be prevented from being consumed.

The toner pattern 10 is preferably formed with the maximum developing width of the developing device 4 corresponding to the entire length of the edge of the cleaning blade 9. However, when it is desired to suppress the toner consumption, it is effective to form the cleaning blade 9 only in the range corresponding to both ends where the turning-up of the cleaning blade 9 is likely to occur. Further, when the photosensitive drum 1 is stopped, if the toner pattern 10 is exposed from the toner receiving port 7a of the cleaning device 7, it may cause toner spills and dust to be scattered. It is preferable that the length in the rotational direction of 1 is such that it fits in the toner receiving port 7a of the cleaning device 7 as shown in FIG.

In order to satisfy the above preferable conditions, FIG.
As shown in the figure, the toner pattern 1 formed with the maximum development width
0 corresponds to the size of the toner receiving port 7a of the cleaning device 7, the leading end 10-1 reaches the cleaning blade 9, and the rear end 10-2 of the photosensitive drum 1 is the toner receiving port. It is preferable that the photosensitive drum 1 is stopped in a state where the photosensitive drum 1 is in the position 7a.

However, it is needless to say that the present invention is not limited to this, and it is preferable to reduce the toner consumption amount on condition that the turning of the cleaning blade 9 at the start of driving of the photosensitive drum 1 can be prevented. . Toner pattern 1
In the case of 0, it is sufficient that the toner is uniformly present in the pattern, and a mesh pattern or a grid pattern may be used instead of a solid image.

In order to determine the timing for forming the toner pattern 10 as described above, it is preferable to detect the image forming state, for example, the end point of the image exposure by the detecting means 26 utilizing the internal control function of the CPU 22 or the like. According to this detection result, a toner pattern is formed on the photosensitive drum 1 at a necessary time before the motor 21 stops, and when the photosensitive drum 1 stops, the toner pattern 10 is changed to the state and position shown in FIG. What should be done is. This makes it possible to reliably prevent the cleaning blade 9 from turning the photosensitive drum 1 while minimizing toner consumption.

Although not shown, the photosensitive drum 1
Detecting means for detecting the specularity of the photosensitive drum 1, detecting means for detecting the driving torque of the photosensitive drum 1, detecting detecting the rotation time of the photosensitive drum 1, detecting the temperature and humidity around the photosensitive drum 1. A condition in which the cleaning blade 9 is easily turned up; a state in which the photosensitive drum 1 is in a mirror surface state; a state in which the frictional force between the cleaning blade 9 and the photosensitive drum 1 is large; If the toner pattern 10 is formed as necessary by detecting a condition such as a high ambient temperature or high humidity,
Excess toner consumption can be further suppressed.

[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 schematic configuration diagram showing a state where a toner pattern according to the present invention is formed by the apparatus of FIG. 1;

FIG. 3 is a schematic configuration diagram showing a preferable state in which a photosensitive drum is stopped after forming the toner pattern of FIG. 2;

FIG. 4 is a block diagram schematically showing a main configuration of a control circuit of the apparatus shown in FIG.

[Explanation of symbols]

 Reference Signs List 1 photoconductor drum 2 charging device 3a image exposure device 4 developing device 5 transfer device 9 cleaning blade 10 toner pattern 21 motor 22 CPU 24 start key 25 toner pattern forming means 26 detecting means 27 transfer material

Continued on the front page (72) Inventor Shinya Matsuura 2-3-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka Inside Osaka International Building Minolta Co., Ltd. (72) Inventor Kazuhiro Sakamoto 2-chome Azuchi-cho, Chuo-ku, Osaka-shi, Osaka No. 13 Osaka International Building Minolta Co., Ltd.

Claims (3)

[Claims] An image carrier, a driving unit for driving the image carrier for image formation, a latent image forming unit for forming a latent image on the image carrier, and a developing unit for developing the latent image on the image carrier. Developing means for transferring a visible image on the image carrier to a transfer material; and at least cleaning for cleaning residual matter remaining on the surface after transferring the visible image on the image carrier. An image forming apparatus comprising: a cleaning unit having a blade; and a toner pattern forming unit configured to form a toner pattern on the image carrier after the image is formed and before the driving unit stops. 2. An image carrier, a driving device for driving the image carrier for image formation, a latent image forming device for forming a latent image on the image carrier, and a developing device for developing the latent image on the image carrier. Developing means for converting the visible image on the image carrier to a transfer material to form an image, and residue remaining on the surface after transferring the visual image on the image carrier A cleaning unit having at least a cleaning blade for cleaning the image forming unit; a detecting unit for detecting an image forming state; and forming a toner pattern on the image carrier before the driving unit stops according to a detection result of the detecting unit. An image forming apparatus comprising: a toner pattern forming unit. 3. The driving unit is stopped before a rear end of the toner pattern passes through the cleaning unit.
3. The image forming apparatus according to claim 2.