JPS62121480A - Cleaning device - Google Patents

Abstract

PURPOSE:To remove residual toner almost completely without damaging an image formation body by providing a conductive roller which is applied with a potential having a different polarity from the residual toner at the upstream side of a main cleaning means and specifying the potential. CONSTITUTION:The image formation body drum 1 is provided with a toner recovery toner 3 made of a conductive material at the upstream side of a cleaning blade 2 rotatably at slight distance from the surface of the image formation body drum 1 together with the cleaning blade 2, and the peripheral speed of the roller 3 and the moving direction at the gap part are equalized to the peripheral speed of the drum 1. A DC high voltage power source 7b which has the opposite polarity from a charge that toner has and applies a enough potential to attract the toner to the surface of the roller 3 is connected to the toner recover roller 3. The potential (V) of the conductive roller 3 is the upper limit Vmax=4,000.d+200 and lower limit Vmin=2,000.d+200.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an improvement in a cleaning device for removing residual toner etc. adhering to the surface of an image forming body in an electrostatic recording device including an electrophotographic copying machine. It is.

[Conventional technology]

In an electrophotographic copying machine, the so-called residual toner adhering to the surface of the image forming body must be removed before it undergoes processing for forming a new image after being transferred to the recording paper.

Therefore, various cleaning devices have been proposed in which a cleaning member is disposed in contact with the surface of the image forming drum and can automatically remove residual toner in cooperation with the rotation of the image forming drum.

Among them, the blade cleaning device has the simplest structure, yet has high cleaning efficiency, and has the feature of not causing separated toner to scatter or float, so it is used in many electrophotographic devices.

However, on the other hand, the toner separated by the grade will naturally fall onto the surface of the image forming drum and will accumulate and adhere to the residual toner on the image forming drum, which will only increase the cleaning burden on the blade. Moreover, it also has the disadvantage of causing inconvenience in toner collection.

Another disadvantage is that the fallen toner leaks out of the cleaning device and contaminates the outside.

As a means for solving this drawback in the blade cleaning device, a means as shown in FIGS. 3a and 3b is known. That is, a Mylar blade is detached from the cleaning blade 2 below the cleaning grade 2 (referred to as upstream when viewed from the rotational direction of the image forming body drum 10) and is used to remove toner falling on the surface of the image forming body drum 10. 4a is provided so as to be in sliding contact with the surface of the image forming body drum (Fig. 3a),
Upstream of the cleaning blade 2, a foamed roll 4b made of foamed plastic or the like is installed upstream of the cleaning grade 2 and is rotated counterclockwise so as to be in sliding contact with the surface of the image forming drum (Fig. 3b). ), but in either case, the separated toner is pressed against the surface of the image forming drum again, causing the toner to form a film, causing toner leakage, which may cause a malfunction of the device, or the image forming drum 1 There were drawbacks such as damage and deterioration. Japanese Patent Publication No. 47-42340 describes an apparatus for removing toner separated by cleaning grade, which eliminates the above-mentioned drawbacks.

As shown in FIG. 1, a cleaning blade 2 and a toner collection roller 3 made of a conductive material are placed upstream of the cleaning blade 2 and slightly spaced from the surface of the image forming drum 1. The circumferential speed of the toner collecting roller 30 and the direction of movement in the gap are made to be the same as the circumferential speed of the image forming drum. A DC high-voltage power source 7b is connected to the toner collection roller 3 in order to apply a potential having a polarity opposite to that of the toner and sufficient to attract the toner to the surface of the toner collection roller 3.

This device almost completely removes residual toner on the image forming drum, causes less damage to the surface of the image forming drum, prevents toner spillage, and maintains stable performance for a long period of time. It can be maintained.

[Problem that the invention seeks to solve]

However, the above-mentioned Japanese Patent Publication No. 47-42340 discloses the mutual positional relationship between the cleaning blade 2 and the toner recovery roller 3, the gap amount between the surface of the image forming body drum 1 and the toner recovery roller 3, and the toner recovery roller 3. There was no detailed description of the interrelationship with the voltage applied to the voltage, which lacked precision, made it impossible to demonstrate its performance in practice, and could even be harmful depending on the conditions.

The present invention conducted experiments to clarify the above points, and determined the optimum value. Based on this value, a grade cleaning device having a toner collection roller to which the above-mentioned high voltage was applied is configured, and the image forming body is It is an object of the present invention to provide an apparatus that can almost completely remove residual toner on an image forming member without causing damage.

[Means for solving problems]

The above purpose is to provide a cleaning device for removing toner, etc. remaining on an image forming body, which includes a cleaning means for actively scraping and removing toner from the surface of the image forming body, and a cleaning device for removing the toner from the surface of the image forming body; a conductive roller that is rotatably arranged slightly apart from the residual toner and to which a potential of a different polarity than the residual toner is applied;
Unit: ■) is 0 upper limit -V max = 4000 ・d + 20
0 (vlO lower limit...V min = 2000-
d + 200 (V), and the
A cleaning device characterized in that the toner that falls and scatters is collected by a cleaning device (where d is the gap dimension between the surface of the image forming body and the conductive p-layer (unit: mm))
) is achieved by

[Effect]

The present inventors obtained the following experimental results regarding the collection roller.

First, as a result of various experiments regarding the installation position and rotation speed of the toner collection roller 3, we found that it is better to install the toner collection roller 3 as close to the cleaning blade 2 as possible for better toner collection efficiency.
Further, the relative drum speed between the toner collection roller 3 and the image forming body drum 1 is higher (and the preferable range of the circumferential speed V is O≦v
<100mm/IM, but is not limited to this range. ” Second, the surface of the image forming body drum 1 and the toner collection roller 3
Various experiments were conducted regarding the relationship between the gap amount between the toner collector p-ler 3 and the potential applied to the toner collection p-ler 3.

As a result: 1) The polarity of the toner charge and the polarity of the voltage applied to the toner collection roller must be opposite.

11) The smaller the gear d, the better the toner collection efficiency, but the same collection efficiency can be obtained by increasing the applied voltage as the gap d becomes larger.

111) If the magnitude of the applied voltage is smaller than a certain value when the value of the gap d is constant, the collection efficiency will suddenly deteriorate and toner will fall out from between the gaps, whereas if it is larger than a certain value, This causes dielectric breakdown and causes a so-called lightning strike phenomenon, causing leakage, and furthermore, deteriorating and damaging the image forming body.

1v) The relationship shown in Figure 2 is obtained between the magnitude of the above applied voltage and the size of the gap d, and the following functional relationship is obtained from Figure 2 regarding the upper and lower limits of the usable range. It was done.

Upper limit V max = 4000 ・d + 200
Volt lower limit V min =2000-d-200
Bolt However, the dimensional unit of gear knob d is no. In practical terms, Vmax is 4000・d + 100.
Vmin=2000·d-100 volts is preferable.

(2) This result was not only true for the OPC photoreceptor (the same was true for the Se photoreceptor as well).

〔Example〕

According to the above experimental results, the configuration and arrangement of each member are the same as in FIG. 1 described above, but the toner collection roller 3 is installed as close as possible to the cleaning blade 2,
The rotation speed is such that the relative circumferential speed V with respect to the image forming body drum 1 is O≦
Select it so that it is in the range of y < 100u+/sec (
The direction of rotation is opposite to that of the image forming drum 1 and is in the forward direction (see Figure 1). Also, the gear d between the toner collection roller 3 and the image forming drum 1 is used during assembly work or maintenance inspection of the device. It is a size that does not require harshness, and
02 to 0. Do not increase the voltage applied to the toner recovery p-ler 3 unnecessarily. :3rm, and the applied voltage was set to 700v from the graph of FIG.

As a result of good cleaning of the electrostatic recording device equipped with the above-mentioned cleaning device, toner filming does not occur on the photoconductor, and dielectric breakdown of the photoconductor due to lightning strikes does not occur. It was confirmed that the lifespan of the photoreceptor was longer than before.In addition, the inside of the electrostatic recording device was much less contaminated by toner than before, so the accident rate was reduced, and the inside of the device was The burden of cleaning and other services has also been significantly reduced.

Next, another example will be given.

An OPC photoreceptor with a diameter of 100 mm was used as the image forming drum, and a resin coating carrier with an average particle size of 100 μm and a polyester (0.8 wt% silicone resin, 0 styrene-butadiene copolymer) with an average particle size of 9 μm were used as the developer. A two-component developer mainly consisting of toner (containing .2 wt%) was used.

The toner collection roller has a diameter of 14 mm, 12 mm, and 1 mm.
0an, 8m! No. 1 metal roller was used.

Then, set the line speed of the drum to 140 Shoulder H/Se.
C.

Metal p-ra line speed 50 mm/s each
ee, 280 Kuzuho/! An experiment was conducted under the same conditions as in the previous example, except that the line speed of the drum was 58 B/see, and the line speed of the metal roller was 58 III/sea. Similar excellent effects were obtained.

Furthermore, as shown in FIGS. 1 and 3 above, the toner collecting device is placed above the horizontal axis passing through the center of the drum, but it is not limited thereto and may be placed below.

〔Effect of the invention〕

As described above, the arrangement, rotational direction, rotational speed, and magnitude of applied voltage of the important components of the cleaning device have been clarified, and standards for device design have been established, and toner recovery efficiency has been improved without unnecessarily increasing manufacturing costs. Since an extremely high-quality cleaning device can be provided, toner can be used repeatedly and high-quality images with few failures can be obtained. Electrostatic image forming apparatuses including electrophotographic copying machines and the like have been realized.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part showing an embodiment of the present invention, FIG. 2 is a graph showing the relationship between the gear knob d and the voltage value applied to the toner collector, and FIG. 3(a). fbl is a diagram showing a detached toner collecting section of a cleaning device of the prior art. 1 Image forming body drum 2 ・Cleaning 7 Rude 3 Toner collection roller 4 ・Toner scraping blade

Claims (1)

[Claims] In a cleaning device for removing toner, etc. remaining on an image forming body, there is provided a cleaning means for actively scraping and removing toner from the surface of the image forming body, and a cleaning device located upstream of the cleaning means and slightly spaced from the surface of the image forming body. and a conductive roller that is rotatably disposed and to which a potential of a different polarity from that of the remaining toner is applied, and the potential (unit: V) is an upper limit of Vmax=4000 d+200.
A cleaning device characterized in that the lower limit is between Vmin=2000 and d-200, and the cleaning means collects falling and scattering toner. However, d is the gap dimension (unit: mm) between the surface of the image forming body and the conductive roller.