JPH0654403B2 - Paper peeling claw - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a paper peeling claw of a copying machine such as an electrophotographic machine, which is arranged in the vicinity of a photoconductor and peels the paper on which a toner image is transferred from the photoconductor. In particular, the present invention relates to an improvement of a paper peeling claw capable of maintaining peeling performance for a long period of time without damaging the surface of a photoreceptor.

[Prior Art] In a conventional copying machine such as an electrophotographic apparatus, a toner image formed on a photosensitive drum (a) is transferred onto a sheet (c) by a transfer corotron (b) as shown in FIG. The image is fixed by the fixing device (d) to obtain a copy of the original document (f) placed on the platen (e).

By the way, a paper (c) is produced by the transfer corotron (b).
When a toner image is transferred from the photosensitive drum (a) to the paper (c) side by applying an electrostatic charge to the paper (c),
Is electrostatically attracted to the side of the photosensitive drum (a), so unless the sheet (c) is forcibly peeled from the photosensitive drum (a), it enters the cleaning device (g) and causes a serious trouble. there were.

Therefore, conventionally, a method has been adopted in which a paper peeling device is arranged between the transfer corotron (b) and the cleaning device (g) to prevent the occurrence of the above troubles.

And as this device, one that uses a paper peeling claw,
There are a type in which a vacuum device is arranged and peeling by suction force, a type in which a separation belt is arranged to force peeling, and a type in which peeling occurs naturally by utilizing the own weight of the paper (c).

However, the vacuum device is not practical because it has the disadvantages that the device is large and the cost is high, and it is mainly used only for ultra-high-speed machines. Although it is excellent in that the paper (c) can be reliably peeled off, it has the drawback that an image cannot be formed at the edge of the paper (c) and the photosensitive drum (a) is also easily scratched. Further, the one using the self-weight of the paper (c) has an advantage that it does not need to be provided with a special device and is inexpensive, but it is unreliable in terms of surely peeling, and particularly the thin paper (c) is used. In that case, there was a drawback that the reliability was extremely lowered.

On the other hand, the one using the paper peeling claw is relatively inexpensive without image loss, and can be sufficiently used in terms of reliability by appropriately selecting the shape, material, number of the claws, mounting state, etc. Therefore, it is generally widely used, and as shown in FIG. 12, the front end side of the paper peeling claw (h) is disposed in contact with the surface of the photosensitive drum (a).

By the way, as this type of paper peeling claw, as shown in FIG. 13, a wedge-shaped one is known in which a rigid metal such as aluminum or iron is integrally molded. Since this paper peeling claw (h ₁ ) has rigidity, it has the advantage that it does not deform even if it is used for a long period of time and its peeling performance does not deteriorate. When the contact pressure to (1) is high, there is a defect that the surface of the photosensitive drum (a) is damaged due to its rigidity, and the manufacturing cost is high because the processing cost is high.

Therefore, as a paper peeling claw that does not have this drawback, see Fig. 14 ~
A paper peeling claw (h ₂ ) shown in FIG. 15 has also been developed. That is, this paper peeling claw (h ₂ ) is obtained by forming a plate-like elastic body having a thickness of about 50 μm, for example, a stainless steel plate into a band-like body by photo-etching and processing the tip side into a sharp shape. The base material side is fixedly disposed on the support material (j) and the tip end side thereof is disposed in contact with the surface of the photosensitive drum (a) for use. The paper peeling claw (h ₂ ) is more flexible and has a weaker contact force with the photosensitive drum (a) than the paper peeling claw (h ₁ ) integrally formed of metal. (A) It has an advantage that the surface is less likely to be scratched and has an advantage that the contact force can be further reduced by setting the length (l) of the paper peeling claw (h ₂ ) to be long. .

However, this paper peeling claw (h ₂ ) is apt to be deformed when it is used for a long period of time, and there is a drawback that the paper (c) cannot be peeled if its tip end side is bent away from the photosensitive drum (a). In addition, there is a defect that the surface of the photosensitive drum (a) is damaged if it is deformed in the direction of coming into contact with the photosensitive drum (a) side.

Therefore, as a further improvement of the plate-shaped paper peeling claw (h ₂ ), there is known a plate-shaped elastic body formed by increasing the thickness of the plate-shaped elastic body as shown in FIGS. 16 to 17. That is, the paper peeling claw (h ₃ ) has a thickness of 250 to 300 μm, for example.
A plate-shaped stainless steel plate having a shape similar to that shown in FIG. 17 is formed by punching a plate-shaped stainless steel by a punching method and the like, and mechanically polishing the tip side of the plate-shaped sheet peeling claw (h ₂ ). As well
Since the base end side is fixedly arranged on the support material (j) and the tip end side is arranged in contact with the surface of the photosensitive drum (a), the support material (j) has an advantage that deformation is unlikely to occur as the thickness increases. I have.

[Problems to be Solved by the Invention] However, in this paper peeling claw (h ₃ ),
As shown in the figure, when the inclination angle (θ) on the bottom surface (h _b ) side of the leading end portion is formed to be large, the leading end of the paper (c) conveyed along with the rotation of the photosensitive drum (a) causes the paper peeling claw. (H ₃ ) There is a disadvantage that the component force (F ₂ ) of the impact force (F ₁ ) on the side of the photosensitive drum (a) becomes large when it collides with the tip portion, and therefore the surface of the photosensitive drum (a) is There was a problem that it hurt.

On the other hand, when the inclination angle (θ) of the bottom surface (h _b ) of the tip of the paper peeling claw (h ₃ ) is formed small, the component force (F ₂ ) to the photosensitive drum (a) side becomes small, but There has been a problem that the thickness of the leading end of the paper peeling claw (h ₃ ) becomes extremely thin, and deformation easily occurs, and the peeling performance deteriorates over time.

[Means for Solving Problems] The present invention has been made in view of the above problems, and a problem is that a sheet capable of maintaining peeling performance for a long period of time without damaging the surface of the photoreceptor. To provide a peeling nail.

That is, according to the present invention, a plate-shaped claw member that peels a sheet fed by the rotation of the photoconductor when the tip side contacts the surface of the photoconductor, and a sheet that supports the claw member and is peeled from the photoconductor is used. And a concave curved surface shape in which the thickness gradually increases in the peeling direction of the paper from the tip side of the side of the claw member that does not come into contact with the photosensitive member. The paper peeling nail is characterized in that a portion of the tip of the nail member that comes into contact with the photoconductor has a convex curved surface shape.

In such a technical means, a plate-shaped metal material such as stainless steel, iron, phosphor bronze or the like can be used as a material forming the claw member, and the material thickness is photoetching workability, strength required for the claw member, Also, in consideration of the thickness of the paper to be peeled off, etc., it is preferably about 50 μm to 500 μm. As a method of manufacturing the above-mentioned claw member, a photo-etching method that has high processing accuracy, does not cause distortion during processing, and does not cause burrs at the claw ends is preferable. Side etching processing during this photo-etching processing is preferable. As a result, a claw member having a concave curved surface at its tip can be obtained.

Further, as a method of processing the portion of the tip of the claw member that comes into contact with the photosensitive member into a convex curved surface shape, after manufacturing the claw member by a photo-etching method, the claw member is again immersed in the etching treatment liquid. It is possible to use a method of etching the portion of the tip of the nail member that comes into contact with the photoconductor to make the corners round and to form a convex curved surface. As another processing method, a nail member manufactured by a photo-etching method is subjected to electrolytic polishing, and a partial corner portion of the tip of the nail member which comes into contact with the photosensitive member is rounded to be processed into a convex curved surface shape. Is also good.

The peeling claw main body includes a supporting portion that supports the claw member and a guide portion that guides the peeled sheet in a direction away from the photoconductor, and is usually formed of a plastic material having excellent workability.

Further, the supporting portion for supporting the claw member preferably has a structure in which the claw member is sandwiched from both sides in order to increase the supporting strength thereof, and when the thickness of the claw member is thin, the tip end of the claw member is left and the base end is left. A configuration in which the entire side is clamped is desirable.

[Operation] According to the technical means as described above, the tip portion is composed of the concave curved surface-shaped claw member, and the peeling claw main body that supports the claw member and guides the peeled sheet, When the leading edge of the sheet conveyed along with the rotation of the photoconductor collides with the leading edge of the claw member, the leading edge of the sheet is guided along the concave curved surface of the leading edge of the claw member sequentially in the direction away from the photoconductor. , It is possible to weaken the component force of the impact force to the photoconductor side, and the part of the tip of the claw member that comes into contact with the photoconductor has a convex curved surface. Even if the pressure is increased, there is an effect that the photoconductor is less likely to be scratched.

[Embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. A paper peeling claw according to this embodiment is shown in Figs.
As shown in the figure, it is composed of a claw member (1) and a peeling claw main body (2) that supports the claw member (1).

First, the claw member (1) is manufactured by a photo-etching method of a stainless steel plate (SUS 304 CSP) described below, and the planar shape of the tip side thereof is a substantially triangular shape, and the bottom surface of the tip part ( 3) The side shape is a concave curved surface shape whose thickness gradually increases from the tip side to the base side as shown in FIG. 6, and the claw member (1) contacts the photoconductor at the tip. The shape of the portion (1a) to be formed is a convex curved surface shape.

On the other hand, the peeling claw body (2) is formed by integrally molding a plastic material such as ABS resin, and the arm body (4) and the claw member (1) provided on the tip side of the arm body (4). A holding part (5) for holding the paper, a guide part (6) provided on the bottom surface side of the arm body (4) for guiding the paper separated by the claw member (1), and the arm body (4). The mounting hole (10) which is provided at the substantially central portion of the mounting hole (10) is fitted to the rod-shaped mounting member (9) when the paper peeling claw (8) is arranged near the photosensitive drum (7) as shown in FIG. ) And an engaging portion which is provided on the base end side of the arm body (4) and which engages with the fixing portion (11) of the copying machine when arranging the paper peeling claw (8) and regulates the arrangement position. (12)
It is composed of and.

In the paper peeling claw (8) configured as described above, the leading end of the paper (p) conveyed with the movement of the photosensitive drum (7) is the paper peeling claw (8) as shown in FIG. ), The bottom surface (3) side of the tip part of the claw member (1) has a concave curved surface shape whose thickness gradually increases from the tip side toward the base side. Therefore, immediately after the collision, the paper (p) is guided in the substantially same direction as the conveying direction of the photosensitive drum (7),
Then, the vehicle is gradually guided downward.

Therefore, the component force (F ₂ ) of the impact force (F ₁ ) on the photosensitive drum (7) side when the paper (p) collides is remarkably reduced, and the photosensitive drum (7) is less likely to be scratched. It has the advantages of

Furthermore, since the shape (1a) of the tip of the claw member (1) that contacts the photoconductor is a convex curved surface, the part (1a) that contacts the photoconductor is the surface of the photoconductor drum (7). It also has an advantage that the photosensitive drum (7) is not easily scratched even if it comes into contact with.

Therefore, even if the thickness of the claw member (1) is set to be large or a material having high rigidity is used, or the contact pressure of the paper peeling claw (8) to the photosensitive drum (7) is increased, the photosensitive drum Since it does not damage (7), the claw member (1)
It is possible to obtain a paper peeling claw which is unlikely to be deformed and whose peeling performance can be maintained for a long time.

If the thickness of the claw member (1) is small,
As shown in this embodiment, the whole of the base end side of the claw member (1) is left with the tip end side left behind, and the holding part (5) of the peeling claw body (2) is provided.
By sandwiching the claw member with the claw member (1), the rigidity of the tip portion of the claw member (1) is increased, so that the deformation resistance thereof can be improved.

Here, the thickness (T) dimension of the claw member (1), the thickness (t) dimension of the tip portion (13) thereof, and the concave curved surface formed on the bottom surface (3) side thereof shown in FIG. Explaining the length (L) dimension, regarding the thickness (T) dimension of the claw member (1), the photo-etching property of the metal material such as stainless steel constituting the claw member (1) and the strength required for the claw member (1). , And the thickness of the sheet of paper (p) to be peeled off, etc., and is preferably about 50 μm to 500 μm.

Further, the thickness (t) of the tip portion of the claw member (1) is required to be smaller than the thickness of the paper (p) so that the paper (p) can be efficiently separated from the photosensitive drum (7). Since the thinnest sheet (p) has a thickness of about 50 μm, it is preferably 50 μm or less, preferably about 20 μm to 40 μm.

The length (L) of the concave curved surface is preferably set as long as possible so that the impact force of the paper (p) to the photosensitive drum (7) side can be appropriately reduced. (1) The thickness of the tip side becomes thin, which causes an adverse effect of impairing rigidity. Therefore, considering the thickness (T) dimension of the claw member (1), it is preferable to set the range of 0.5T <L <2T ... From the relationship with the thickness (T) dimension.

Below, concrete data about the thickness (t) dimension of the tip portion (13) and the length (L) dimension of the concave curved surface that are suitable for various thickness (T) dimensions of the stainless steel plate are listed.
It becomes like 1.

<Manufacture of Claw Member> A method for manufacturing the claw member (1) used in this example by photoetching will be described below.

First, a photoresist (FSR, manufactured by Fuji Yakuhin Kogyo Co., Ltd., trade name FSR) film is uniformly formed on both sides of a stainless steel plate (sus 304 csp), and pattern exposure is performed from both sides, and then the resist in the unexposed portion is dissolved and removed. Fig. 10 to Fig. 11 (A)
As shown in (3), photoresists (15) and (16) are formed on both surfaces of the stainless steel plate (14) by shifting the tip positions thereof.

Next, this is immersed in an etching solution of ferric chloride solution (FeCl ₃ ) and subjected to photo-etching treatment. The etching proceeds not only in the thickness direction of the stainless steel plate (14) but also in the lateral direction, and is side-etched. 11 A claw member (1) having a tip shape as shown in FIG. 11B is manufactured.

During the side etching process, since the photoresists (15) and (16) are formed so as to be displaced relative to the center line, the tip of the stainless steel plate (14) in contact with the end of the photoresist (15). While the portion corresponding to the portion (1a) contacting the photoconductor is slightly side-etched, the other photoresist (16) side is much more side-etched than the photoresist (15) side.

On the other hand, the shape of the tip of the claw member (1) obtained by the photo-etching treatment is considerably angular as shown by the chain double-dashed line in FIG. 11 (C) regardless of the side etching amount. , Its angle R is R _{1 to} R ₃ μm (that angle R
Has a radius of curvature of 1 μm to 3 μm). Therefore, if the claw member (1) is used as it is as a sheet peeling claw, the surface of the photosensitive drum (7) may be damaged.

For this reason, it is necessary to make at least a portion of the tip of the claw member (1) corresponding to the portion (1a) in contact with the photosensitive member into a convex curved surface. As a processing method thereof, the claw member (1) is used. ) Is immersed in a photoetching treatment solution to etch the tip of the claw member (1) again, or the electrolytic polishing treatment described below is preferably performed.

That is, the nail member (1) was electropolished (liquid composition, 600 ml of phosphoric acid, 300 ml of sulfuric acid, 100 ml of chromic acid, and 50 ml of water).
The claw member (1) was immersed in an electrolytic bath filled with 100 ° C., subjected to electrolytic polishing for 5 minutes under conditions of 100 ° C., DC 10 V (V) and current density of 800 A / dm ² , and
As shown by the solid line in FIG. 6C, the portion (1a) in contact with the photosensitive member was formed into a convex curved surface shape to obtain the claw member (1) of the above example. At this time, at the tip of the claw member (1), not only the portion (1a) contacting the photoconductor but also the other portion (1b) are simultaneously formed into a convex curved surface shape. The angle R of (1b) was R _{5 to} R ₁₀ μm.

When the degree of scratching of the photosensitive drum (7) by the claw member (1) was confirmed, good results were obtained as shown below.

That is, the thickness not subjected to the electrolytic polishing treatment 50μ
m, and a claw member with an edge angle R of R ₂ μm was placed in contact with the surface of the selenium photosensitive drum with its pressing force of 0.9 gf, and continuous copying was performed. In the solid image copy (equivalent to 0.4 to 0.5 gray in Macbeth reflection density), a streak-shaped blank image due to the nail member was found. At this time, the surface roughness of the scratched portion of the photosensitive drum was measured and found to be R _z = 0.22 μm.

On the other hand, the claw member (1) according to this embodiment in which the portion (1a) contacting the photoconductor is electrolytically polished, that is, the claw member (1a) having a corner R of R7 μm (the portion R1a contacting the photoconductor) When a similar inspection was performed using 1), the above-mentioned blank image was discovered only when the number of copies was 60,000, and the nail member (1) according to the example hardly scratches the photosensitive drum (7). It was confirmed.

Although a selenium photoconductor is used as the photoconductor drum (7), the same improvement effect was observed when OPC (organic photoconductor) was used instead of the selenium photoconductor.

[Effects of the Invention] As described above, the present invention comprises a claw member having a concave curved end at its tip and a peeling claw main body which supports the claw member and guides a peeled sheet. When the leading edge of the sheet conveyed along with the rotation of the body collides with the leading edge of the claw member, the leading edge of the sheet is guided along the concave curved surface of the leading edge of the claw member sequentially in the direction away from the photosensitive member. It becomes possible to weaken the component force of the impact force to the photoconductor side,
Since the portion of the tip of the claw member that comes into contact with the photoconductor has a convex curved surface, even if the contact pressure of the paper peeling claw on the photoconductor is increased, the photoconductor is less likely to be scratched.

Therefore, even if the thickness of the claw member is set to a large value or the material having high rigidity is used, the photoreceptor is not damaged and the peeling performance can be maintained for a long period of time.

[Brief description of drawings]

1 to 9 show an embodiment of the present invention. FIG. 1 is a perspective view of a paper peeling claw according to this embodiment, FIG. 2 is a side view thereof, and FIG. 3 is a plan view thereof. FIG. 4 is a bottom view thereof, FIG. 5 is a partially enlarged view of FIG. 4, FIG. 6 is a sectional view taken along line VI-VI of FIG. 5, and FIG. FIG. 8 is a diagram for explaining the action of the sheet peeling claw, FIG. 9 is a diagram for explaining the dimensions of the claw member, and FIGS. 10 and 11 show the manufacturing process of the sheet peeling claw. , Tenth
The figure is a plan view in which photoresist is formed on both sides of the stainless steel plate, FIG. 11 (A) is this vertical cross-sectional view, and FIG. 11 (B) is a vertical cross-sectional view showing the side-etched state during photoetching. FIG. 12 (c) is a vertical sectional view of the obtained nail member, and FIG. 12 is an explanatory view of a copying machine for electrophotography, FIG.
FIGS. 18 to 20 show a conventional paper peeling claw, FIG. 13 is a perspective view of an example thereof, FIGS. 14 and 15 are side views and plan views of other conventional examples, and FIGS. FIG. 18 shows another conventional example, FIGS. 16 and 18 are side views thereof, and FIG. 17 is a plan view thereof. [Description of symbols] (1) …… Claw member (2) …… Peeling claw body (4) …… Arm body (5) …… Clamping part (6) …… Guide part (8) …… Paper peeling claw (10) ) …… Mounting hole (12) …… Engagement part

Claims (4)

[Claims] Claim: What is claimed is: 1. A plate-shaped claw member, the front end of which is in contact with the surface of a photoconductor and peels off a sheet fed by the rotation of the photoconductor, and a sheet which is peeled while supporting the claw member. And a tip of the nail member on the side not in contact with the photoconductor, which has a concave curved surface shape whose thickness gradually increases from the tip side toward the sheet peeling direction. In addition, the paper peeling claw is characterized in that the portion of the tip of the claw member that comes into contact with the photoconductor has a convex curved surface shape. 2. Manufactured by a photo-etching processing method,
The sheet peeling claw according to claim 1, wherein a claw member in which the concave curved surface shape is formed by a side etching process at the time of this processing is used. 3. A photo-etching method is used for manufacturing,
The sheet peeling claw according to claim 1, wherein a claw member in which the convex curved surface shape is formed by a re-etching process after this processing is used. 4. A photo-etching method is used for manufacturing,
The sheet peeling claw according to claim 1, wherein a claw member having the convex curved surface shape formed by electrolytic polishing treatment after the processing is used.