JP2955949B2 - Cleaning device for image forming apparatus - Google Patents

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 electrophotographic method such as an electrostatic copying machine and the same printer, and more particularly to a cleaning device thereof. .

(Prior Art and Problems to be Solved) In a known image forming apparatus that repeats a step of transferring a transferable toner image formed on the surface of an image carrier onto a transfer material such as paper, the transfer is performed on the transfer material during transfer. It is essential that the residual toner remaining on the image carrier be sufficiently cleaned each time.

Various cleaning means have been proposed for this purpose, but one edge of one edge of a blade made of an elastic material such as urethane rubber is brought into contact with the image carrier at a position after transfer. It is well known that the method of removing and removing the residual toner has a simple structure, is small in size, is advantageous in cost, and has an excellent toner removing function, so that it is widely used. .

As described above, urethane rubber is frequently used as a cleaning blade in this type of cleaning device, and it is normal that the blade is brought into contact with the traveling direction of the surface of the image carrier in a counter direction. Since urethane rubber has a large frictional force with the image carrier, it is large especially when a cleaning blade is first attached to the image carrier and activated, or when a large amount of images with low toner consumption are continuously copied. In some cases, the blade edge is turned up in the running direction of the image carrier due to friction, so that cleaning becomes impossible.

In order to avoid such a situation, it has been practiced to apply a fluorine-based fine resin powder such as polyvinylidene fluoride or polytetrafluoroethylene to the blade edge portion or the surface of the image carrier to act as a lubricant. However, such a means is not easy to apply uniformly in the longitudinal direction of the blade edge, and it becomes impossible to suppress the occurrence of the above-mentioned turning over of the blade due to dispersion of the application, or the amount of the powder is large. If too large, inconveniences such as adversely affecting the electrostatic characteristics of the image carrier and the toner cannot be avoided.

Further, while repeating the cleaning action, the fine powder disappears from the blade edge portion, and instead the toner acts as a lubricant, but in this case, the reduction of the lubrication action is inevitable, For this reason, in particular, when an organic semiconductor having relatively low mechanical strength is used as the photosensitive layer, the photosensitive layer is damaged and the problem of shortening the life of the image carrier remains.

In addition, as the urethane rubber, a thermosetting cast type liquid urethane is used because it has excellent abrasion resistance to the image carrier and does not contaminate the image carrier with components leached from the image carrier. However, such a material has a long time until heat curing and a high reactivity with moisture in the air, and thus has a problem in cost and quality control in manufacturing equipment.

The present invention provides a cleaning device for an image forming apparatus,
The urethane blade has been made to address the above-described problems, and has a low friction with the image carrier at all times without damaging the surface thereof. An object is to provide a blade with stable quality.

(2) Configuration of the Invention (Technical Means for Solving the Problems and the Function) To achieve the above object, the present invention provides a cleaning apparatus using a cleaning blade which is pressed against an image carrier, wherein the cleaning blade is made of silicon. The cleaning blade is made of a rubber composition, has an edge at an image carrier contact portion, and is formed integrally with a rigid support member as a positioning reference for setting a contact state with the image carrier by injection molding. However, this is a cleaning device in which the low-viscosity organosiloxane component contained in the silicone rubber is 5% by weight or less, the rubber hardness is in the range of 40 to 90 ° according to JISA, and the compression set is 20% or less.

With this configuration, the cleaning blade itself wears into a fine powder form and acts as a lubricant, so that stable cleaning can always be performed without turning over the blade.

FIG. 1 is a sectional side view of a cleaning apparatus suitable for applying the present invention, which has an axis perpendicular to the paper surface and is close to an image carrier 1 which rotates in the direction of arrow a. The cleaning device 5 is disposed in parallel with the support member 2 made of a rigid material such as metal and attached to the cleaning device.
An elastic cleaning blade 3 is integrally attached by injection molding, and one edge of the blade 3 is pressed against the surface of the image carrier 1 in the counter direction.

When the residual toner that has not been transferred to the transfer material at the transfer portion (not shown) reaches the position of the cleaning blade 3, the toner is scraped off by the blade 3 and stored in the cleaning device. Reference numeral 4 denotes a rake sheet.

In addition, although not shown, a primary charger, an image signal applying unit, a developing unit, a transfer unit, and other members necessary for image formation are of course arranged around the image carrier.

The cleaning blade is 100 g of TSE3032 (trade name: manufactured by Toshiba Silicon Co., Ltd.), which is an addition-type liquid silicon material that performs hydrosilylation reaction of hydrosilane with a polysiloxane polymer having a vinyl group at the end in the presence of a platinum-based catalyst.
Inject a hydrosilane crosslinking agent into a vinylpolysiloxane polymer obtained by adding a platinum-based catalyst to hydrophobic dry-processed silica RX200 (trade name: Nippon Aerosil Co., Ltd.) 20g with a hardness adjusted by the silicone resin component and reaction rate. The mixture was molded by injection using a molding machine.

The mold to be injected is heated to 170 ° C. in advance, and the rubber is injected into the mold with the support member 2 bonded with a vulcanizing adhesive attached thereto, and 60 seconds after the injection, the rubber is injected into the mold. The integrated cleaning blade 3 was removed from the mold and subjected to secondary vulcanization at 200 ° C. for 4 hours.

Thus, a cleaning blade having a rubber hardness of 66 ° (JISA), a low viscosity organosiloxane component (oil content) of 2.6% by weight and a compression set (70 ° C.) of 7% was obtained.

The cleaning blade made of the silicone rubber composition is the same as the above-mentioned TSE 3032 silicone material as the base material.
The silica as a filler is not limited to the RX-200, and as the filler, molybdenum disulfide as an inorganic fine powder, fluorocarbon, and the like, and an organic fine powder are not limited. Can be used as a multi-component system by using ultra-high-density polyethylene, nylon, fluorine-based resins, or the like alone or by appropriately mixing them.

Regarding the shape of the blade edge, in FIG.
It is preferable that the illustrated angle θ formed by both side surfaces of the edge b is approximately 90 °, but this angle can be appropriately set in the range of 70 to 90 °.

One surface c forming the edge b may be left as it is after molding if the molding accuracy is high, but it is preferable to cut the surface c to increase the accuracy.

In order to use the filler with the edge formed as it is, unless the above-mentioned filler has a primary particle size of 1 μm or less, the edge accuracy may be reduced and cleaning failure may be caused.

The means for setting the relative position between the cleaning blade and the image carrier will be described with reference to FIG.

Protrusions 6, 6 for positioning the blade are formed on the surface of the cleaning container on the side where the cleaning blade is provided, and the blade support member 2 has concave portions 6 that engage with these protruding portions 6. , 6 'are provided, and by locking them together, the amount of penetration of the blade indicated by symbol e in FIG. 4 into the image carrier is determined. In this case, the intrusion amount is expressed as a distance between the blade edge f and a surface (actually a line) g corresponding to an intersection with a surface including the blade edge facing the image carrier, in a state where the blade is not deformed. ing.

The direction in which the cleaning blade 3 contacts the image carrier 1 is as shown in FIG. 3 at an angle α with respect to a tangent to the image carrier 1 at a contact point b between the blade edge and the image carrier.
It is preferable to set the angle to about 15 to 30 °, and the contact pressure is 6.5 to 45 gr / cm.

As an embodiment, an OPC photoconductor is used for the image carrier,
Rubber hardness 66 mm (JISA), angle α is 25 mm, penetration amount 0.8 m
When a paper passing test was performed on 3,000 sheets at a pressure of 30 gr / cm and m, there was no defective image due to scratches on the image carrier, no blade turning during initial operation and during operation, and a good image was obtained until the end. Was done.

Further, as described above, this blade contained only 2.6% by weight of a low-viscosity organosiloxane component, so that there was no oil leaching.

It was confirmed that up to about 5% by weight of the oil ganosiloxane component, there was no leaching of oil.

If the hardness of the silicon rubber blade is too low, the rubber will be weak and the slidability will deteriorate due to contact with the image carrier on a large surface, so it is desirable to have a hardness of JISA40 ゜ or more. If the hardness is too high, the image carrier may be damaged, so the hardness is preferably JISA hardness 90 ° or less,
Preferably, JISA is 50 to 80 mm.

If the pressure of the cleaning blade against the image carrier is too small, for example, if the pressure is 6.5 gr / cm or less as described above, cleaning failure will occur, so that it is necessary to maintain a certain level of pressure. Due to this, irreversible deformation (creep) occurs inside the rubber, so that a smaller one is preferable. For this purpose, the compression set is 20% or less,
Preferably, it is 10%.

As the material of the silicone rubber, any material can be used as long as it satisfies the above requirements, such as a room temperature curing type RTV, a low temperature curing type LTV, and a high temperature curing type HTV.
LTV, which is an addition type liquid silicone rubber, is preferred in view of the rapid reactivity to heat, the absence of reaction residues, and the small amount of molding shrinkage.

As described above, by using silicon rubber as the cleaning blade, a cleaning blade which is extremely stable and has a good cleaning function can be obtained.

FIG. 5 shows another embodiment of the present invention. In the illustrated apparatus, the cleaning blade is in contact with the image carrier 1 in the forward direction.

The means for attaching the blade support member 2 to the container 5 of the cleaning device is the same as that shown in FIG. 1, and corresponding portions are denoted by the same reference numerals.

The blade 3 of the illustrated apparatus is a deformed blade having a slope portion h formed. With such a configuration, local stress concentration due to the deformation of the blade is reduced to perform stable cleaning over a long period of time. be able to.

FIG. 6 shows a mold (lower mold) for forming a cleaning blade according to another embodiment, in which a part 2 'for setting a blade support member in a mold 7 and a part 3' for pouring a blade material are formed. I have.

A large number of minute irregularities are formed in the portion 3 'into which the blade is poured, and the contact surface side of the formed blade is roughened so as not to impair the cleaning property, thereby further reducing the friction of the blade. It is possible to reduce the occurrence of blade turn-up and to reduce the driving torque of the image carrier.

In this case, when the average particle diameter of the toner to be cleaned is about 10 μm, it is preferable that the irregularities be R _z = 1 μm or less.

It goes without saying that the cleaning blade thus configured can be applied to both the counter arrangement and the forward arrangement.

FIG. 7 shows a mold for producing a cleaning blade. In the case shown, three blades can be formed in one mold at a time.

A lower mold 71 and an upper mold 72 having a plurality of support member installation sites 2 'and a blade material pouring site 3' are overlapped with each other, and liquid silicon is injected from an injection hole 8 formed thereby to form a blade. However, it goes without saying that the number of blades formed at one time is not limited to three.

Taking advantage of the speed of reaction of liquid silicon and the advantage of being able to form by injection, the productivity can be greatly improved in the manner described above.

(3) Effect of the Invention As described above, according to the present invention, when an elastic cleaning blade is used as a cleaning means, the cleaning blade is mainly made of silicone rubber and contains a low-viscosity organosiloxane. Ingredients are 5% by weight or less, rubber hardness is 40 ~ 90mm in JISA and compression set is 20% or less. As it wears, it is always present between the blade edge and the image carrier and acts as a lubricant, reducing the friction between the two without causing blade turnover and image carrier damage. It has a remarkable effect of always obtaining a stable cleaning action and obtaining a high quality image, and a reliable blade can be efficiently manufactured by using injection molding. Also to cost down is valid.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side sectional view of a cleaning device suitable for applying the present invention, FIG. 2 is a perspective view of a main part showing a cleaning blade positioning means, and FIG. FIG. 4 is a side view of a main part for explaining a contact condition to the image carrier; FIG. 4 is an explanatory view for explaining an amount of a cleaning blade penetrating into the surface of the image carrier; FIG. FIGS. 6, 6 and 7 are a plan view and a perspective view, respectively, showing a mold for manufacturing the cleaning blade according to the present invention. DESCRIPTION OF SYMBOLS 1 ... Image carrier, 2 ... Support member, 3 ... Cleaning blade, 4 ... Rake sheet, 5 ... Container, 6 ... Positioning protrusion.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 21/10

Claims (1)

(57) [Claims] 1. A cleaning apparatus using a cleaning blade that is in pressure contact with an image carrier, wherein the cleaning blade is made of a silicone rubber composition, has an edge at an image carrier contact portion, and The cleaning blade is formed integrally with a rigid support member serving as a positioning reference for setting the contact state by injection molding. The cleaning blade has a low viscosity organosiloxane component contained in silicone rubber of 5% by weight or less and a rubber hardness of JISA. It is in the range of 40 to 90 ゜ and has a permanent compression set of 20%
A cleaning device that is: