JPH034285A - Image forming device - Google Patents

Abstract

PURPOSE:To clean a cleaning blade rapidly and surely by forming an electrifying part on a photosensitive drum before an image forming action starts or after its completion, and controlling so that the electrifying part passes by the top part of the cleaning blade. CONSTITUTION:An electrifying device 6, a exposure device 4, a developing device 7, a transfer device 12, a separating device 13, a cleaning device 16 and a destaticizing lamp 8 are provided around a photosensitive drum in that order. The destaticizing lamp 8 destaticizes the surface of the photosensitive drum 5 after residual toner is scraped off by the cleaning blade 20 provided in the cleaning device 16. Moreover the transfer device 12 forms the electrifying part 9 on the photosensitive drum 5 in the cleaning process of the cleaning blade 20. The cleaning blade 20 is fixed on one side end of a holding member 11, turns in the direction of an arrow E, centered around a blade rotating shaft 21, and then, the surface of the photosensitive drum which rotates in the direc tion of an arrow D abuts on or separates from the top part of the cleaning blade 20. This abutting and separation are controlled by a control circuit 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus. More details can be found in an image forming apparatus such as an electrophotographic copying machine that is provided with a cleaning device that removes residual toner from the surface of a photoreceptor drum using a cleaning blade.

Figure 5 is a schematic diagram of an electrophotographic copying machine. A charging device (6), an exposure device (4), a developing device (7), and a transfer device (
12), separation bag ff (13) and cleaning equipment! (1
6) is provided. Charging device (6) and exposure device (
4) forms a latent image on the photoreceptor drum (5),
Next, toner development is performed by a developing device (7).
The image developed on the photoreceptor drum (5) is transferred to the paper feeder (
22) onto a transfer paper (not shown) introduced from the transfer device (12). The transfer paper after the transfer is separated from the photosensitive drum (5) by the separation bag 1 (13) and then discharged to the outside of the copying machine main body (26).

Inside the cleaning device (16) is a cleaning plate.
The drum (20) is provided so that its tip can come into contact with the surface of the photoreceptor drum (5). Residual toner on the photosensitive drum (5) is scraped off by a cleaning blade (20).

The cleaning blade (20) is made of an elastic material such as rubber, but if it is kept in pressure contact with the photoreceptor drum (5) for a long time, the photoreceptor drum (5) will be dented, causing image defects. Therefore, conventionally, the cleaning blade (20) is separated from the photosensitive drum (5) at the end of the copying operation.

However, as the copying operation is repeated, as shown in FIG.
Not only the blade surface (23) but also the blade back surface (23)
Toner (25) also adheres to 4). Back side of blade (2
The toner (25) adheres to the surface of the photosensitive drum (5) rotating in the direction of arrow (B) or the blade surface (23).
), etc., caused by scattering of toner (25).

As shown in FIG. 6, when a copying operation is performed with toner (25) attached to the back surface of the blade (24), the residual charged portion of the photoreceptor drum (5) is transferred to the cleaning blade (20). There is a problem in that when the toner passes through the tip, the toner (25) on the back surface of the blade (24) adheres to the residual charged portion and is transferred as part of the image.

Therefore, in order to solve the above problems,
In Publication No. 2477q, a charging device charges a photoreceptor drum to form a charged portion, and this charged portion passes through the tip of a cleaning blade while an exposure device, a developing device, and a transfer device 1 separation device are not operating. A method of cleaning the cleaning plate has been proposed in which the toner adhering to the cleaning blade is adsorbed to the charged portion before copying is started, and the toner is removed. In this cleaning method, the developing device is not operated when the charging portion passes through the developing device, thereby preventing toner from the developing device from adhering to the charging portion.

On the other hand, Japanese Patent Application Laid-Open No. 61-132981 proposes a recording device in which a cleaning blade is brought into contact with a photoreceptor drum and mechanical vibration is applied to the photoreceptor drum to remove toner adhering to the cleaning blade. ing.

However, in general, even when the developing device is not operating, the charged portion of the photoreceptor drum attracts toner from the developing device as it passes through the developing device. , in a configuration in which a portion charged by a charging device passes through a developing device as is, as in Japanese Patent Application Laid-Open No. 59-152477, toner from the developing device adheres to the charging portion, resulting in wasted toner consumption. However, it is also possible to prevent toner from adhering to the charging section by separating the developing device from the photoreceptor drum, or by providing a mechanism for shielding the opening of the developing device and a control means for controlling its operation. However, there is a problem that the device becomes complicated.

In addition, in order to reliably prevent toner from adhering to the charging section, the timing for cleaning the cleaning blade must be set when the toner is not charged; however, the cleaning blade must be cleaned immediately after the image forming apparatus finishes operating. In this case, this cleaning method cannot be used because the toner is still electrically charged. In other words, with this method, the cleaning blade must be cleaned after a considerable amount of time has passed after the copying operation is completed. For this reason, in the case of electrophotographic copying machines where copying is actually done frequently, cleaning blades can only be cleaned when the main switch is turned on first thing in the morning, however, depending on the number of copying operations. As a result, the amount of toner adhering to the cleaning blade increases, and as time passes, the toner adhering to the cleaning blade tends to stick to the blade surface. Therefore, if cleaning of the cleaning blade is limited to when the main switch is turned on as described above, it is difficult to completely and reliably remove toner adhering to the cleaning blade.

In addition, in the configuration in which a charging device charges the photoconductor drum for cleaning the cleaning blade as in the conventional example described above, the distance between the charging device and the cleaning device is long, so if the circumferential speed of the photoconductor drum is slow. There is also the problem that the charging voltage must be set high in advance because the potential of the charging section is greatly reduced and the toner adsorption effect of the cleaning blade is reduced.

On the other hand, in the device disclosed in JP-A-59-152477, toner is removed by mechanical vibration force applied to the cleaning blade, but a portion of the removed toner is scattered outside the cleaning device. It may adhere to the transfer device, the copy paper conveyance path, etc. and contaminate the inside of the device.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems, and to quickly and efficiently clean the cleaning blade at a low voltage before the start of image forming operation and/or after the end of image forming operation with a simple configuration without consuming toner in the developing device. An object of the present invention is to provide an image forming apparatus that can perform image formation reliably.

In order to achieve the above-mentioned object of cleaning the buds, the present invention provides an image forming apparatus in which a transfer device and a cleaning device are sequentially arranged around a photoreceptor drum. By operating the transfer device for a predetermined period of time, a charged portion is formed on the photoreceptor drum, and the tip of a cleaning blade provided in the cleaning device so as to be able to come into contact with the surface of the photoreceptor drum is charged. The structure includes a control means for controlling the passage of the part.

In particular, it is preferable that the cleaning blade is provided with a vibration imparting means that generates mechanical vibrations in the cleaning blade by bringing the cleaning blade into contact with and separating from the surface of the photoreceptor drum.

The vertical shell transfer device is located downstream of the developing device in terms of the rotational direction of the photosensitive drum. Therefore, the charged portion of the photoreceptor drum formed by the transfer device according to the configuration of the present invention contacts the cleaning blade as it is, so that
Toner adhering to the cleaning blade is efficiently adsorbed.

Next, when the photoreceptor drum comes into contact with the developing device due to continued rotation, most of the charged parts already have toner attached (by the cleaning device), or have been neutralized by the static elimination lamp and are only slightly or slightly charged. Almost no toner exists.Therefore, toner in the developing device is not adsorbed wastefully.

Regarding the potential of the charging portion formed on the photoreceptor drum, since the rotational distance from the transfer device to the cleaning device is short, when it comes into contact with the cleaning blade, the potential at approximately the time of charging is maintained.

Furthermore, when the cleaning blade is provided with a vibration imparting means that generates mechanical vibrations, the toner scattered by the vibration is electrically attracted to the charging section, so that the toner is not scattered outside the cleaning device. The inside of the image forming apparatus main body is not contaminated with toner.

Examples of the present invention will be described below based on the drawings. Note that the same parts as those described in the related art are given the same reference numerals and detailed explanations will be omitted.

FIG. 1 is a schematic diagram of essential parts of an electrophotographic copying machine showing an embodiment of the present invention. A charging device (6), an exposure device (4), and a developing device (7) are installed around the photosensitive drum (5) with an inner diameter of 90 mm (peripheral length of 90 πam) that rotates in the direction of arrow (C) at a circumferential speed of 80 III/sec. ), a transfer device (12), and a separation device (13).

A cleaning device (16) and a static elimination lamp (8) are provided. As shown in FIG. 2, the static elimination lamp (8) removes residual toner from the photoreceptor drum (5) after the residual toner is scraped off by the cleaning blade (20) provided in the cleaning device (16). Eliminates static electricity on the surface of Note that the static elimination lamp (8) is installed at a position extending from the transfer device (12) toward the rotation direction of the photoreceptor drum (5) at an angle of about 120° with respect to the center of rotation. Further, the transfer device (12) forms a charging portion (9) on the photoreceptor drum (5) in the cleaning process of the cleaning blade (20).

FIG. 2 shows how the cleaning device (16) operates. The cleaning blade (20) is fixed to one end of the support member (11), rotates in the direction of arrow (E) about the blade rotation axis (21), and cleans the photoconductor rotating in the direction of arrow (D). The surface of the drum (5) contacts and separates from the tip. This contact and separation is performed by a weight (10), a solenoid (1), a drive circuit (2), and a control circuit (3).

The control circuit (3) is constituted by a microcomputer or the like, and operates the drive circuit (2). The drive circuit (2) operates the solenoid (1). When the solenoid (1) is activated, the weight (10) provided at the end of the supporting member (11) on the side where the cleaning blade (20) is not provided is pulled up by the magnetic force of the solenoid (1). The tip of the cleaning blade (20) separates from the surface of the photoreceptor drum (5) (cleaning blade (20) OF F). When the solenoid (1) is inactive, the weight (10) causes the tip of the cleaning blade (20) to come into contact with the surface of the photoreceptor drum (5) (cleaning blade (20) ON). , the drive circuit (2), the control circuit (3), and the weight (10) perform 0N10FF of the cleaning blade (20), and at the same time, these also move the cleaning blade (20) onto the surface of the photoreceptor drum (5). By making contact and separation, it also acts as a vibration imparting means that generates mechanical vibrations in the cleaning blade (20).

In this example, a weight (10) and a solenoid (1
) Cleaning blade (20)
is rotated in the direction of the arrow (I, for example, JP-A-61-1
A solenoid and a pressure spring may be used as disclosed in Japanese Patent No. 32981, or a combination of a solenoid, a pressure spring, and a weight may be used.

The operation of this embodiment shown in FIG. 1 will be explained below as shown in FIG. 3 (
This will be explained based on a)(b) and FIG.

FIG. 3(a) is a flowchart showing the main operations of this embodiment. When the copying machine is turned on in step (I1), it is determined in step (I2) whether or not the copying machine is in a stable state. This determination is made depending on whether various conditions are satisfied, such as, for example, that the temperature of each part within the copying machine is constant.

If the copying machine is not in a stable condition, step (12) is repeated until it is stabilized. If the n5 machine is stable, proceed to step (13).

In step (I3), cleaning of the cleaning blade (20), which will be described later, is performed.

Next, in step (I4), it is determined whether a print key (not shown) is turned on. print key is on
If not, step (I4) is repeated until it is turned on. If the print key is turned on, the process advances to step (I5) and a copying operation is performed.

Next, in step (I6) it is determined whether the copying has been completed. If the copy has not finished, step (
Return to step I5), and if the copying is complete, click Step (
Proceed to cloud 7).

Step (Iwa 7) is a process of cleaning the cleaning blade (20), similar to step (I3). When step (tooth 7) is completed, the main operation of the copying machine is completed.

Next, cleaning of the cleaning blade (20) will be explained based on FIG. 3 Q:1) showing the subroutine of step (I3) and step (117) and FIG. 4 showing the timing chart thereof. The operation of each part is controlled by control means including the control circuit (3).

First, in step (1100) the cleaning blade (
20), a main motor (not shown) that rotates the photoreceptor drum (5), a developing bias power source (not shown) that applies a bias voltage to prevent toner from scattering from the developing device (7), and a static elimination lamp (8). ) and transfer device (12) are turned on.
state. FIG. 4 shows the 0N10FF operation of each of the above-mentioned parts after this time is assumed to be 0 seconds. In addition, in this subroutine for cleaning the cleaning blade (20), the charging device (6) and the separating device (13)
is in the OFF state.

Next, in step (1101) it is determined whether one second has elapsed. If one second has not elapsed, the determination in step (1101) is repeated until one second has elapsed.

When one second has elapsed, the process advances to step (1102). Step (1102) 't' is the cleaning blade (2o
) turns off. Next, in step (11103), the step (1102) cleaning block l/-)"(
20) is judged whether one second has elapsed since the OFF Lte. Here, wait for 1 second to elapse, and when 1 second has elapsed, proceed to step (1104).Step (11104)
), the cleaning blade (20) is turned on. Then, in step (1105), step (1104)
Then, it is determined whether one second has passed since the cleaning blade (20) was turned on. If 1 second has elapsed here, proceed to step (1106). In step (cloud 106), the cleaning blade (20) and transfer device (12)
turns off.

As mentioned above, the charged portion (9) is formed on the photoreceptor drum (5) by turning on the transfer device (12) for 3 seconds.
When passing through the tip of the cleaning blade (20), the toner adhering to the cleaning blade (20) is absorbed and removed. At the same time, the cleaning blade (20) is turned off after 1 second by the vibration applying means.
, by turning on after 2 seconds and turning off after 3 seconds, the adhering toner is scattered and the toner can be more effectively attracted to the charging section (9). Furthermore, paper powder adhering to the tip of the cleaning blade (20) can also be removed by using the vibration applying means in combination. The paper powder is generated from the transfer paper, and if it adheres to the tip of the cleaning blade (20), it will cause damage to the photoreceptor drum (5).
The surface may not be cleaned properly.

In step (1106), the static elimination lamp (8), the main motor, and the developing bias power supply remain in the ON state, and in step (11107), after the transfer device (12) and cleaning blade (20) are turned off, .4
It is determined whether or not seconds have elapsed. If 1.4 seconds have not elapsed, step (1110?) is repeated until it has elapsed, and if it has elapsed, proceed to step (110B).

The rear end of the charged portion (9) moves 112+wm (143
°) Move. As described above, since the static elimination lamp (8) and the transfer device (12) are arranged at an angle of about 120° with respect to the center of the photoreceptor drum (5), the charging section (9) all pass through the static eliminating lamp (8) when the static eliminating lamp (8) is in the ONO state. Therefore, the charged portion of the photoreceptor drum (5) does not pass through the developing device (7). Of course, step (1) is not limited to 1.4 seconds, but can be performed after the charging section (9) has passed the static elimination lamp (8).
108) may be performed.

In step (1108), the main motor, the developing bias power source, and the static elimination lamp (8) are set to 0FFL, and the above cleaning process of the cleaning blade (20) is completed. As explained in FIG. 3(a), this cleaning step is performed before and after the copying operation, so during the copying operation that is performed after the cleaning operation is completed, the charging section (9) is moved to the cleaning blade ( 20) to be scraped off and removed.

Mitsuho and Yosei As explained above, according to the image forming apparatus of the present invention, after the charged portion is formed on the photoreceptor drum by the transfer device, it reaches the cleaning device without passing through the developing device. The cleaning blade can be reliably cleaned before the start of the image forming operation and/or after the end of the image forming operation with a simple configuration without consuming toner in the developing device.

Furthermore, since the distance between the transfer device and the cleaning device is short, the cleaning blade can be cleaned quickly, and the potential drop of the charging portion over time is small.
As a result, the cleaning blade can be effectively cleaned with a low voltage.

In particular, according to an image forming apparatus in which the cleaning blade is provided with a vibration imparting means that generates mechanical vibrations, the toner scattered from the cleaning blade due to the vibration is statically deposited on the charged portion formed by the transfer device. Since it is electrically attracted, the cleaning blade can be cleaned more reliably without contaminating the outside of the cleaning device.

Moreover, since paper dust adhering to the cleaning blade can also be removed, there is also the effect of suppressing the occurrence of cleaning failures caused by adhesion of paper dust.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the main parts of an electrophotographic copying machine for explaining the present invention, FIG. 2 is an explanatory diagram of its cleaning device, and FIG.
FIG. 4 is a flowchart showing the operation of an embodiment of the present invention, FIG. 4 is a timing chart thereof, FIG. 5 is a schematic diagram of a conventional electrophotographic copying machine, and FIG. 6 is an explanatory diagram of its cleaning blade. (1)... Solenoid, (2) --- Drive circuit. (3) --control circuit, (4) --exposure device. (5) . . . Photosensitive drum, (6) . . . Charging device. (7)...Developing device, (8)...-Static elimination lamp. (9)... Charged part, (10) -... Weight. (11)...Supporting member, (12)--Transfer device. (13)...Separation device, (16)...Cleaning device. (20)...Cleaning blade. (21)--Blade rotating shaft, (22)--Paper feeding device. (23) --- Blade surface, (24) --- Blade back surface. (25)--Toner, (26)-Copying machine body.

Claims (2)

[Claims] (1) In an image forming apparatus in which a transfer device and a cleaning device are sequentially provided around a photoreceptor drum, the photoreceptor drum is A charging section is formed in the cleaning device, and control means is provided for controlling the charging section to pass through a tip of a cleaning blade provided in the cleaning device so as to be able to come into contact with the surface of the photoreceptor drum. An image forming apparatus characterized by: (2) The device according to claim 1, further comprising a vibration imparting means for generating mechanical vibrations in the cleaning blade by bringing the cleaning blade into contact with and separating from the surface of the photoreceptor drum. Image forming device.