JPH04170560A - Picture forming device - Google Patents

Abstract

PURPOSE:To prevent generation of a defective picture by arranging a member for giving a toner to an image carrier in the upstream of a cleaning blade of a cleaner, forming an area of no adherence of the toner in this member and also arranging a spacer roller in a developer side brought into contact with a part of the image carrier corresponding to this area. CONSTITUTION:A spacer roller 9 in a developer side is brought into contact with an image carrier 1 in a location corresponding to both end parts of a magnet roller 3 in a cleaner side and a part A where a toner layer is cut by an end part scraper 12. Since no toner is provided in this cut part, a contact pressure of a cleaning blade 2 with an image carrier 1 is large generated, that is, cleaning action is strong by the blade, so that the toner, sticking to this cut part, can be easily removed eve when the toner is pressed by the spacer roller 9. In this way, a space between a developing sleeve 11 and the image carrier 1 can be accurately held to always obtain a good picture.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention (Field of Industrial Application) The present invention relates to an image forming apparatus using an electrostatic transfer process, such as an electrostatic copying machine and a printer thereof.

(Prior Art and Problems to be Solved) In the above-mentioned image forming apparatus, which processes fine powder toner to form an image, in addition to a cleaning blade for removing residual toner on the image carrier, A magnetic roller is installed, and a magnetic brush formed on the roller rubs the surface of the image carrier to remove fine paper dust generated from the paper used as the transfer material, precipitates such as rosin and talc, and high-pressure components inside the device. Measures have been proposed to remove foreign matter adhering to the image carrier due to the presence of corona products.

In this way, a cleaning means that uses a magnetic roller together with a cleaning blade does not require special magnetic particles to be prepared to form a magnetic brush when a one-component magnetic toner is used. The collected toner can be sequentially used for this purpose, and by appropriately setting the relationship with the cleaning blade, an appropriate amount of toner for lubrication can be supplied to the edge of the cleaning blade that contacts the image carrier. This method has the advantage of being able to maintain the functionality of the cleaning device.

On the other hand, if a magnetic brush is formed on the magnetic roller, a considerable amount of toner will adhere to the brush, which inevitably causes problems in the treatment of toner, particularly near both ends of the brush.

This will be briefly explained with reference to FIG. 5, which schematically shows the relative arrangement of the developing device side I and the cleaner side (1) in the vicinity of one end using a known device.

In the side work of the developer, the developing sleeve 11 is pivotally supported by the side wall 10 of the developer casing, and the spacer roller 9 disposed on the outside comes into contact with an image carrier (not shown) to prevent the development sleeve 11 from interfering with the image carrier. Maintaining spacing.

On the cleaner side (3), a cleaning blade 2 is placed in pressure contact with an image carrier (not shown), and a magnetic brush 7 formed on a magnet roller 3 is arranged to rub the surface of the image carrier.

In such a configuration, as shown in the figure, the spacer roller 9 is located at a position C where an end seal 8 exists for preventing toner from escaping from the side wall of the cleaner casing.
existed.

Therefore, as the copying process progresses, the toner that has entered between the end seal 8 and the image carrier, which are in contact with the image carrier, is fused and assimilated to the image carrier, and the spacer rollers 9 contact the image carrier. The body surface may be uneven, and the distance between the developing sleeve 11 and the image carrier may vary, resulting in uneven density in the image.

In order to avoid such problems, it is conceivable to arrange the spacer roller 9 on the outside of the end seal 8 on the cleaner side, as shown in the figure.
There is a drawback that the developing device has to be larger, and
There is no cleaning blade on the surface of the image carrier at the position where the spacer roller 9 comes into contact with the image carrier, and cleaning of this area is not performed. The decline is inevitable.

When the relative arrangement of each member is as shown in Figure 5, if the spacer roller 9 is disposed at the position where the cleaning blade 2 cleans the image carrier, at the part B in the diagram,
It was found that cleaning problems and the occurrence of scattered toner became noticeable, making it unsuitable for practical use as a side sole.

This will be explained with reference to FIG.

This figure is a schematic side view showing a rotating cylindrical image bearing member 1 and a cleaner C disposed close to the image bearing member 1, in which residual toner that has not been transferred to a transfer material at a transfer site (not shown) is cleaned. When it reaches the position of the cleaning blade 2, it is scraped off and removed, and the magnetic brush formed on the surface of the magnet roller 3 disposed upstream of the cleaning blade 2 (as seen in the running direction of the image carrier 1) The toner layer becomes a toner layer whose thickness is regulated by the regulation roller 4, and as the magnet roller rotates, it reaches a position close to the image carrier and rubs the surface thereof.

In this case, a portion of the toner layer reaches the position of the cleaning blade 2 as indicated by the reference numeral 7, and a considerable amount of toner is supplied to the blade edge portion, the portion B in FIG. This function stabilizes the contact state of the cleaning blade with the image carrier.

By the way, in such a state, if the spacer roller 9 exists in the part B as described above, a small amount of toner that happened to be scattered will arrive at the position of the spacer roller and be pressed against it, and this toner will be removed by the blade in the cleaner section. If the blade cannot be removed completely and the blade is lifted from the image carrier, as described above, a large amount of toner present in this area will escape through the blade, and this will be pressed against the image carrier by the spacer rollers and become firm. This creates a vicious cycle in which more toner adheres to the surface of the toner, causing even more toner to fall out, which rapidly leads to poor cleaning and deterioration of image quality.

The present invention has been made in order to cope with such a situation.In an image forming apparatus having a cleaning device equipped with a cleaning blade and a magnetic roller that applies toner to the cleaning blade, the present invention is provided with a cleaning device for a spacer roller on the developing unit side. It is an object of the present invention to provide an image forming apparatus that maintains the position maintenance function of the spacer roller over a long period of time and can always obtain good images by appropriately setting the positions corresponding to the cleaning blade, magnet roller, etc. This is the purpose.

(2) Structure of the Invention (Technical Means for Solving the Problems and Their Effects) In order to achieve the above object, the present invention provides an image forming apparatus in which a cleaning blade is installed in the cleaner and a cleaning blade is installed in the cleaner when viewed from the running direction of the image carrier. a toner applying member to the cleaning blade located upstream of the cleaning blade, and means for forming a portion at both ends of the toner applying member where toner is not applied to the image bearing member; A spacer roller is used to set the gap between the developing sleeve and the surface of the image carrier.
It is characterized in that it comes into contact with a portion of the toner applying member on the image carrier side that corresponds to a portion where toner is not applied.

With this configuration, the surface of the image carrier that comes into contact with the spacer roller on the developing unit side can be kept clean at all times, and the distance between the developing sleeve and the image carrier can be accurately maintained.

(Description of Embodiments) FIG. 1 is a side view of an image forming apparatus showing an embodiment of the present invention near a portion where a cleaning device exists, and is arranged close to an image carrier 1 rotating and traveling in the direction of arrow A. The edge of the cleaning blade 2 of the cleaning device is in contact with the edge of the cleaning blade 2, and a magnet roller 3 is disposed upstream of the blade 2 when seen in the running direction of the image carrier 1. A regulating roller 4 is provided to regulate the movement of the air, and these functions are the same as those shown in FIG.

Reference numeral 12 indicates an end scraper for cutting the toner layer on the magnet roller, which is arranged at both ends of the magnet roller, reference numeral 5 indicates a scraper for the regulation roller 4, and reference numeral 6 indicates a conveyance screw for discharging the collected toner. It is.

In the illustrated apparatus, an amorphous silicon photoreceptor with a diameter of 100 mm is used as an image carrier, and a process speed of 4 is used.
The cleaning blade was made of polyurethane rubber with a thickness of 13 mm.
It was brought into pressure contact with the image carrier at a pressure of gr/cm.

Further, FIG. 2 shows the magnet roller 3 and the regulating roller 4, including the image carrier 1, the cleaning blade 2 of the cleaner, the end seal 8, the magnet roller 3 and the toner layer 7 formed thereon, and the developing sleeve on the developing device side. 11. Spacer roller 9
FIG. 2 is a schematic diagram of the vicinity of the end portion showing the relative arrangement of FIG.

As shown in the figure, the spacer roller 9 on the developer side is located at both ends of the magnet roller 3 of the cleaner example, and at the end scraper 1.
2, the toner layer is in contact with the image carrier 1 at a portion corresponding to the cut portion A.

Since there is no toner in this cut portion, the contact pressure between the cleaning blade 2 and the image carrier 1 is large (in other words, since the cleaning action by the blade is strong, the toner adhering to this portion is pressed by the spacer rollers 9). can be easily removed.

Experiments were conducted using the apparatus configured as described above and the case where the spacer rollers were present in the B section in FIG. The toner that had passed through the cleaning blade adhered and began to be fused by the rollers, and at around 10,000 sheets, a considerable amount of toner fell out, resulting in a large amount of scattered toner.

In the former case, even after continuous copying of 200,000 sheets, no toner slip-through or fusion occurred, the gap between the image carrier and the spacer roller was maintained as set, and no deterioration in image quality was observed.

FIG. 3 shows the shape of the toner layer cut portion at the end of the cleaning blade and the corresponding end of the magnet roller, and FIG. 3(a) shows the cut state shown in FIG. 2. There is.

As can be seen from the figure, the shapes of the toner cut portions in FIGS. The amount of toner in parentheses is such that it does not come into contact with the image carrier.

This is because if the toner in this area is completely cut off, as mentioned above, there will be no lubricating effect on the toner between the blade edge and the image carrier, and the coefficient of friction will increase, causing the blade edge to This is to prevent the pressing force from becoming too strong and causing chatter at the end of the blade and eventually causing the blade to turn over.

In the cleaning device described above, a device that uses the magnetic roller itself as a means for applying toner to the cleaning blade has been described, but the toner applying means is not limited to this, and a device in which the magnetic roller is surrounded by a sleeve, and a fourth It is also possible to use a fur brush as shown in the figure.

FIG. 4A shows the relationship between the fur brush and the cleaning blade when a fur brush is used. At the end of the fur brush 13, there is a brush at a portion A corresponding to the spacer roller on the developing device side. There shall be a portion that does not form.

FIG. 4B shows a structure in which a magnetic roller is disposed inside.

Note that the fur brush may be rotated in any direction relative to the image carrier, and may be fixed.

3. As described in detail, according to the present invention, a member for applying toner to the image bearing member is disposed upstream of the cleaning blade of the cleaner, and an area where toner is not attached to the member is formed. By arranging the spacer roller on the developing device side in contact with the image carrier portion corresponding to the area, the portion of the image carrier that the spacer roller contacts is cleaned by the cleaning blade, and the distance between the image carrier and the sleeve is reduced. It has a remarkable effect on obtaining high-quality images that can be maintained constant at all times and that do not cause image defects due to uneven density.

[Brief explanation of the drawing]

FIG. 1 is a side view of an image forming apparatus in the vicinity of a cleaner showing an embodiment of the present invention; FIG. 2 is a schematic diagram showing the relative positional relationship of an image carrier, a cleaner, and a developing device; FIG. 3 is a magnet FIG. 4A and FIG. 4B are perspective views of main parts showing the configuration of other toner applying members. FIG. 5 is a diagram showing a cleaner and a developing device of a known image forming apparatus. FIG. 6 is a schematic side view of the cleaner illustrating the behavior of toner within the cleaner. I... Image carrier, 2... Cleaning blade, 3
...Magnetic roller, 4...Regulation roller, 7...
- Toner layer, 8... End seal, 9... Spacer roller, 11... Developing sleeve, 12... End scraper. Figure 1 Figure 2 Section 3 Figure 4A Figure 48 Figure 5

Claims (3)

[Claims] (1) The cleaner has a cleaning blade and a toner applying member to the cleaning blade located upstream of the cleaning blade as viewed in the running direction of the image bearing member, and the image bearing member is attached to both ends of the toner applying member. A spacer roller for setting a gap between the developing sleeve of the developing device and the surface of the image carrier is provided with a means for forming a part on which toner is not applied, and a spacer roller is provided to form a part on the toner applying member where toner is not applied. An image forming device that is in contact with a portion on the carrier side. (2) The image forming apparatus according to claim 1, wherein the means for applying toner to the cleaning blade is a magnetic roller. (3) The image forming apparatus according to claim 1, wherein the means for applying toner to the cleaning blade is a fur brush.