JPH0815996A - Transfer paper separating device - Google Patents

Abstract

PURPOSE:To prevent the deterioration of an image quality due to the toner omission without damaging the image carrier by adequately selecting the condition of a separating pawl in a transfer paper separating device adopting the separating pawl consisting of resin for separating the transfer paper while coming into contact with the image carrier. CONSTITUTION:The tip of the separating pawl 2 held in contact with the image carrier 1 is in a pyramidal shape, and when assuming the angle formed by the tangent of the image carrier 1 on the separating pawl contact point and the separating pawl contact face as alpha( deg.), the upper face projection pyramidal angle of the separating pawl 2 as theta2( deg.), the upper face projection tip radial of the separating pawl 2 as R(mum), the projection pyramidal angle of the separating pawl 2 in the rotary shaft direction of the image carrier l as theta1( deg.) and the projection tip radial of the separating pawl 2 in the rotary shaft direction as r(pm), the condition of the separating pawl 2 is set so that Bg, theta2, r, R, and alphais severally provided with the respective value so as to satisfy the following numerical formula, 2tan(theta2/2)(R (1/sin(theta2/2)-1)+r(cos(theta1/2)/ tan-(alpha+(theta1/2)+1))<200.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer paper separating device applied to a copying machine and a printer using an electrophotographic system.

[0002]

2. Description of the Related Art As a means for separating a transfer sheet electrostatically adsorbed on a photosensitive member and reliably conveying it to the next step,
In many cases, a separating claw is provided in the transfer paper separating device (Japanese Patent Laid-Open No. 3-245173, Japanese Patent Laid-Open No. 3-140666, Japanese Utility Model Publication No. 60-184070, Japanese Utility Model Publication No. 51-4).
3136).

In recent years, resin-made separating claws have come to be used from the viewpoints of reducing damage to the photoconductor and cost merit. 13, the separation claw 2 is adhered and held to the separation claw holder 3 that holds the separation claw. The separation claw holder 3 is rotatably fitted to a support shaft 4 provided in the rotation axis direction (direction perpendicular to the paper surface of FIG. 13) of the drum-shaped photoreceptor 1, and the transfer paper 10
While the photoconductor is rotating by means of a cam etc.
It is designed to move back and forth.

The reciprocating motion is such that the separating claw is made of resin, but has a certain hardness, so that the photosensitive member is damaged by contact with the photosensitive member. , In order to disperse these scratches, they are reciprocating. Alternatively, in the case of using a metal nail, there is one in which the abdomen of the nail is brought into contact with the photoconductor to protect the photoconductor and the nail position is fixed.

Regarding the separation claw capable of reciprocating movement, the separation claw is rotatably held on a support shaft, and the tip of the separation claw is pressed by a biasing means toward the center of the photosensitive member f. Are contacted at. Alternatively, instead of using a pressure spring, a configuration may be employed in which the rear portion 3a of the separation claw holder 3 centering on the support shaft 4 is brought into contact by utilizing the rotational moment due to its own weight.

In the image forming process, the toner image formed on the photoconductor 1 is transferred onto the transfer paper 1 at a predetermined transfer position.
Transcribed to 0. The transfer paper 10 after transfer is the conveyor belt 11
The leading end is separated from the photoconductor and is conveyed to the fixing process section by the conveyance belt 11 in the process of being sent by, but some of them reach the cleaning section 12 without being separated from the photoconductor. Since the image forming process cannot be continued with this, the transfer paper is separated by the separation claw 2 in advance. This is the function of the separating claw.

Most of the toner forming the toner image on the photoconductor 1 is transferred onto the transfer paper 10 as indicated by the reference symbol Tt, but some of the toner is indicated as the transfer residual toner by the reference symbol Tr. As described above, not all of them are transferred onto the transfer paper by transfer, but some of them may remain on the photoconductor.

When the transfer residual toner is scraped off by the separating claw, it falls on the transfer paper due to gravity and stains the image surface of the transfer paper.

The shape of the tip of the separating claw 2 is shown in FIG. 17 (a).
(Top view), FIG. 17 (b) (front view), FIG. 17 (c)
As shown in (a cross-sectional view as seen from the direction of the arrow in FIG. 17C), or as shown in FIG. 18A (top view), FIG.
As shown in (front view) and FIG. 18 (c) (a cross-sectional view as seen from the direction of the arrow in FIG. 18 (c)), the cross-section has a square or circular cone-like shape. The pointed shape is formed in this way because the width of scraping off the residual toner Tr is small when the pointed tip portion contacts the photoconductor 1 as shown in FIG. Incidentally, as shown in FIG. 19, the contact width W ₁ is narrower than the width of the residual toner Tr, whereas when the contact width W ₂ is large as shown in FIG. 20, the separation claw scrapes the transfer paper. The amount of toner that is dropped (hereinafter referred to as toner drop) is also increased, which increases the amount and range of soiling of the transfer paper and the degree of image defects.

Further, as the material of the separating claw, for example, a material having a high hardness such as polyimideamide is used, and in order to reduce damage to the photoconductor, it is reciprocally moved in the axial direction of the photoconductor by a mechanical means such as a cam. In the case of the configuration, as shown in FIGS. 21 to 22, in the case of the separating claw device that swings the separating claw 2 in the direction of the arrow along the support shaft 4, the separation claw 2 moves in the direction of the arrow in the swinging operation. Due to the gap between the separation claw holder 3 and the fitting portion, the tip of the claw is inclined with respect to the photoconductor 1 and a gap d is generated.

[0011]

Even if the contact area of the separation claw with respect to the photoconductor is reduced as described above, the tip of the separation claw tends to wear over time and the contact width with the photoconductor tends to increase. Is inevitable. Compared to the case where the contact width is narrow as W ₁ as shown in FIG. 19, when the contact width is as large as W ₂ as shown in FIG. 20, the transfer residual toner scraped on the image carrier (photoconductor) is scratched. There is a problem in that the amount of toner removed increases due to the increase in the amount of removal, and the image quality is impaired.

Further, as shown in FIGS. 21 and 22, in the structure in which the separating claw is constantly reciprocally moved on the support shaft by a mechanical means such as a cam, the separating claw is moved during the movement. A gap is created due to the inclination, and the toner enters the gap and passes while being rubbed by the separation claw, so that the toner abrades the separation claw at the time of this passage, and the abrasion amount increases, and The separation claw, which has a small contact width as shown in FIG. 14, has a large contact width W due to abrasion as shown in FIG. 15 (front view) and FIG. There is a problem with it.

Further, if the hardness of the separating claw is too high, the image carrier will be damaged and streaks will appear on the image.
When it is too low, abrasion of the separation claw is promoted, and the image quality is deteriorated due to toner loss.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a transfer paper separating device capable of appropriately selecting the condition of the separating claw and preventing the deterioration of the image quality due to the toner drop.

[0015]

In order to achieve the above object, the present invention is configured as follows.

(1). The tip of the separation claw that comes into contact with the image carrier is a pyramid shape, and the angle between the tangent line of the image carrier and the separation claw contact surface at the separation claw contact point is α (°). The weight angle is θ ₂ (°), the top projection tip radius of the separation claw is R (μm), the projection weight angle of the separation claw in the rotation axis direction of the image carrier is θ ₁ (°), the rotation axis When the projected tip radius of the separating claw in the direction is r (μm), ₂ tan (θ 2/2) [R {1 / sin (θ ₂ /
2) -1} + r _{[cos (θ 1/2) /} tan {α +
_{(Θ 1/2)} -} sin satisfy (theta _{1/2) +1]] <200, θ 1, θ} 2, r, we decided to use the separation claw having a value of R, alpha (claim 1) .

(2). In (1), the separation claw has a material Rockwell hardness of H ≦ 109 (M scale) (claim 2).

(3). In (2), the separating claw is movable in the rotation axis direction of the image carrier, and has a means capable of being fixed so as not to move in the rotation axis direction (claim 3).

[0019]

With respect to the first aspect, when such conditions are set, the wear width of the separation claws with time (= contact width with the image carrier)
Is 200 μm or less, and beyond this, it is difficult to increase. According to the second aspect, it is possible to reduce the abrasion speed of the separation claws while reducing the occurrence of scratches on the image carrier and the progress of the scratches. According to the third aspect, the separation claw does not always reciprocate, but can be fixed at a predetermined position for separating the transfer paper while the latent image carrier is rotating. There is no room for the separation claw to tilt with respect to the image carrier during rocking, and there is no acceleration of wear caused by the gap.

[0020]

EXAMPLE The separating claw is applied to the photoconductor, and a drum-shaped or belt-shaped dielectric is disposed so as to face the photoconductor, mainly for use in a color image copying machine or the like. There is also a system in which a toner image formed on a photoconductor is transferred onto the dielectric and then further transferred onto a transfer paper. In such a system, a separation claw is applied to the dielectric. In some cases, the image carrier to which the present invention is applied includes a dielectric in addition to the photoconductor.

(1). Description corresponding to claim 1.

Regarding the wear of the separating claw, the wear width (= contact width:
The relationship between W) and the toner removal level was tested and summarized in FIG. Here, for the determination of the toner removal level, items such as the number of black dots per unit area on the transfer paper, the size of the black dots, the frequency of occurrence of black dots (how many sheets are generated during copying, etc.) are determined. It was used as a scale and visually judged.

Here, the maximum black dot diameter of one toner drop is 0.5 mm ((-) charged toner having an average particle diameter of 7.5 μm is used), and the ratio of black spots per cm ² is 3% or less. It has a level.

According to this, the toner particle size, toner shape,
Depending on the combination of factors such as toner material, toner charge polarity, etc., and the material of the photoconductor, the toner adhesion force and toner adhesion amount to the photoconductor vary, and the toner drop level fluctuates. It was found that when the width: W) is 200 μm or less, the toner removal level falls within the allowable level and does not significantly deteriorate the image quality.

Therefore, how to set the condition of the separation claw becomes a problem in order to keep the wear width (= contact width: W) within a predetermined value, that is, within 200 μm. With respect to this point, as shown in FIG. 5, when the R shape (rounded shape) of the tip of the separation claw 2 remains, there is a gap on the photoconductor 1 in the acute angle portion of the tip indicated by the arrow j. The residual toner easily enters, and therefore the abrasion progresses due to the polishing effect of the toner. However, when this abrasion progresses and the tip R-shaped portion disappears as shown in FIG. Since it is in close contact with the peripheral surface of No. 1, the residual toner on the photoconductor 1 flows to the upper part of the separation claw as shown by the arrow k,
Alternatively, even if it is blocked, it does not enter under the separation claw, and the above polishing effect does not occur.

Therefore, the present inventor found that the contact width W when the tip R-shaped portion of the separating claw disappears can be obtained by the following calculation formula, and this and the contact width within 200 μm as described above. It has been found that by combining the conditions in which abrasion is less likely to occur when the setting is set to, it is possible to suppress an increase in the contact width and prevent toner from falling off.

A calculation formula for obtaining the contact width W when the tip R-shaped portion of the separating claw disappears will be described with reference to FIG. FIG.
1A is an enlarged view of a portion surrounded by a circle when the separation claw 2 shown in FIG. 1B is viewed from the rotation axis direction of the photoconductor 1, and FIG. As shown in FIG. 1 (d), when the separation claw 2 is viewed from above, it is an enlarged view of a portion surrounded by a circle.

In FIG. 1, the angle between the tangent line of the image carrier and the separation claw contact surface at the separation claw contact point is α.
(°), the top projection weight angle of the separation claw is θ ₂ (°), the top projection tip radius of the separation claw is R (μm), and the projection weight angle of the separation claw in the rotation axis direction of the photoconductor 1 is θ ₁ ( ), And the projected tip radius of the separation claw in the rotation axis direction of the photoconductor 1 is r (μm).

When the separating claw 2 is worn until the rounded end of the claw 2 disappears, reference numeral LL in FIG. 1 (a) indicates a wear line. Assuming that the distance from the intersection Q of the center line OO and the wear line L-L to the tip of the separation claw is denoted by the symbol d, the wear width (= contact width: W) can be obtained using the distance d. .

D = c + r-b (1) where c is the distance on the center line OO from the intersection Q to the intersection H between the wear line LL and the contour line of the separating claw. Further, b is an intersection point J (the center of the projected tip radius r of the separation claw) where a perpendicular line on the contour line of the separation claw raised from the intersection point H intersects with the center line OO, and a center line OO through the intersection point H. The distance on the center line OO between the lowered intersection K is shown. b, c
Each value of can be obtained as follows.

The a / c = tan {α + (θ 1/2)} c = a / tan {α + (θ 1/2)} = r · cos (θ 1/2) / tan {α + (θ 1/2 )} (2) where a is the distance from the intersection K to the intersection L.

[0032] _{b = r · sin (θ 1} /2) ... (3) (2), is substituted into (3) Equation (1), ∴d = r _{[cos (θ 1/2) /} tan { _{α + (θ 1/2}} -sin (θ 1/2) +1 ] (4) On the other hand, in FIG. 1 (c), the intersection of both the contour of the separating claw O _3, from to the intersection point Q the intersection point O ₃ Of the wear width (= contact width: W) on the center line OO of the separation c from the intersection point O ₃ to the center M of the projection projection tip radius R of the separation claw OO. Assuming that the above distance is f, W = 2g ... (5) g = e · tan (θ ₂ /2)...(6) e = f + d−R ... (7) where f · sin (θ ₂ / When f is calculated from 2) = R, f = R / sin (θ ₂ /2)...(8) Here, from equations (7), (4), and (8), e = R [{1 / _{sin (θ 2/2)}} - 1 ] + r [co _{(Θ 1/2) / tan} {α + (θ 1/2)} - sin (θ 1/2) +1 ]] ... (9) (9), (5), (6) where, W = 2 tan (θ
_{2/2) [R {1} / sin (θ 2/2) -1} + r [co
_{s (θ 1/2) /} tan {α + (θ 1/2)} - sin
(Θ _1/2) +1]].

Therefore, the value of W obtained by this equation is 200 μ
θ that satisfies the condition of being within m ₁, Θ₂, R, R, α
When the condition of the separation claw is set to have the value of
Even if you earn a number, you can suppress the increase in contact width and
-It can prevent falling.

The result of an experiment for confirming this is shown in FIG. FIG. 3 shows data obtained by measuring the actual wear width for each number of transferred sheets by using three types of separation claws satisfying the condition of W <200 in calculation. The conditions of the separating claw shown by the solid line are R = 75 μm and r = 60 μm, the conditions of the separating claw shown by the broken line are R = 75 μm and r = 35 μm, and the conditions of the separating claw shown by the one-dot chain line are R = 50 μm and r. = 25 μm, and the common condition for each of these separating claws is α = 13
(°), θ ₁ = θ ₂ = 30 (°), pressing force of the separating claw f = 1
g / f, the material of the separating claw is polyetherimide (PE
I), the tip shape of the separating claw is a quadrangular pyramid as shown in FIG. In FIG. 3, for each of these separation claws, the actual wear width W (μm) is measured and graphed for each copy number (transfer number).

In FIG. 3, in any separating claw,
The actual wear width (W) is 200 even with a separation claw with a large wear width.
It does not exceed about μm, and the calculated value and the experimental value are in good agreement. In fact, these separation claws did not cause deterioration of image quality due to toner loss over time.

(2). Description corresponding to claim 2 Generally, on the surface of the photoreceptor, a resin that is not easily worn or scratched, such as a polycarbonate resin, is used. During rotation of the photoconductor, the separation claw is fixed so as not to swing in the rotation axis direction of the photoconductor, and the tip of the separation claw is configured to abut the same position on the rotation axis direction of the photoconductor, When the material of the photoconductor was changed and the depth of scratches on the surface of the photoconductor with respect to the number of copies (the number of copies) was measured for each material, the results shown in FIG. 4 were obtained.

In FIG. 4, reference numeral PAI indicates the experimental result when polyamideimide (Rockwell hardness / M scale 119) was used as the material of the separating claw.

Further, reference numeral PEI is polyetherimide (Rockwell hardness / 109 on M scale), reference numeral PEEK
Is polyetheretherketone (Rockwell hardness, M
106) on the scale, and PEEK 'with the reference numeral represent the experimental results when polyetherketone (Rockwell hardness / 99 on the M scale) was used as the material of the separating claws.

In this example, when polyimide amide was used, the rising of the straight line was steeper than in the other examples, and the number of transferred sheets (200,000 sheets) was reached, which is the life level of the image bearing member (photoreceptor). It can be seen that the depth of the scratch on the image bearing member reaches the level at which streaks are generated in the image before reaching, so that it cannot be set as an appropriate material condition.

Codes PAI, PEI, PEEK, PEE
In all other material conditions indicated by K ′, the depth of the scratch on the surface of the image bearing member reaches the level at which streaks are generated in the image, and still reaches the life level of the image bearing member. It turns out to be appropriate.

It is considered that the hardness of the material is mainly related, and if the hardness of the material of the separating claw is 109 or less on the Rockwell M scale, it is considered to be appropriate as the material. In other words, this hardness does not cause image defects due to damage to the image carrier until the life of the image carrier.

(3). When the position of the separation claw is always fixed and used at an arbitrary position in the rotation axis direction of the photoconductor, for example, when the image is a key line, and the position of the key line is used. When the position of the separation claw and the position of the separation claw match, the separation claw continues to be positioned at the position corresponding to the key line, so that the residual toner after transfer continuously drops and the image quality is significantly deteriorated. . Even in the case where the separation claw is swung in the rotation axis direction of the photoconductor, when the key line, the band-shaped image, the specific format, etc. exist within the swing range, the transfer residual toner Toner drops occur intermittently, degrading image quality.

Further, in the system in which the separating claw swings in the direction of the rotation axis of the photosensitive body during rotation of the photosensitive body, as described with reference to FIGS. The abrasion is accelerated, and the image quality is deteriorated due to the toner loss. It is intended to provide a technique capable of avoiding such deterioration of image quality.

In FIG. 7, the two separating claws 2 are both
The support shaft 4 is rotatable, but its movement is restricted in the longitudinal direction of the shaft, and the support shaft 4 moves together with the support shaft 4. The separation claw 2 is adhered to a separation claw holder 3, and the separation claw holder 3 is attached to the support shaft 4.
A spring S ₁ hung between the upper protrusion and the upper protrusion urges the photosensitive member 1 to abut.

The support shaft 4 has ribs 13 provided on the immovable member 14.
And is supported so as to be movable in the axial direction. A step portion 4a is formed on the right end side of the support shaft 4, and an extensible spring S ₂ is interposed between the step portion 4a and the rib 13, so that the support shaft 4 is moved to the right in the drawing. Is urged to. The movement of the support shaft due to this urging is prevented by the right end of the support shaft 4 contacting the positioning plate 5 provided on the immovable member 14.

The positioning plate 5 is fixed by a screw 6 through an elongated hole having a longitudinal direction in the rotational axis direction of the photosensitive member 1.
4 is fixed. Therefore, if the positioning plate 5 is moved after loosening the screw 6, the separation claw 2 is also moved in the rotation axis direction of the photoconductor together with the support shaft 4.

Here, the spring S ₂ , the positioning plate 5, the elongated hole and the screw 6 constitute an example of a fixing means that makes the position of the separating claw movable and fixes the position.

With this configuration, for example, the symbol T in FIG.
Even if transfer residual toner is generated at the position of the separation claw 2 as indicated by r, the separation claw 2 is moved to the transfer residual toner Tr as shown in FIG.
The removal claw 2 does not cause the phenomenon of toner loss due to the removal of the transfer residual toner Tr.

9 and 10 show another example. Instead of attaching the support shaft 4 to the positioning plate 5 as shown in FIG. 7 and FIG. 8, the end of the support shaft 4 is screwed. It is configured such that it is connected to the portion 9 and the threaded portion 9 is screwed through the drum face plate 8 as a stationary member.

A knob 7 is provided at the end of the screw portion 9. By rotating this knob 7, the spindle 4
Can be moved in the direction of the rotation axis of the photoconductor 1. Therefore, also in this example, since the position of the separation claw can be appropriately changed by the movement of the separation claw and the fixing means at the predetermined position, by shifting the position of the transfer residual toner or the position of the separation claw, It is possible to avoid deterioration of image quality due to toner loss. In the examples of FIGS. 9 and 10, no tools are required, which is particularly convenient.

In a mechanism in which two separating claws positioned at regular intervals are used and the transfer paper is conveyed with the center as a reference, as shown in FIG. The movable range of the separation claw needs to be set so as to cover the area.

Further, in this example, in any of the examples of FIGS. 7 and 8 and FIGS. 9 and 10, once the position of the separating claw is set, the position of the separating claw is set at that position. Since the separation claw does not swing during the rotation of the photosensitive member, the gap d as shown in FIGS. 21 and 22 does not occur, and the separation claw shown in FIG. Since the leading end of the sheet does not form a gap by closely contacting with the photoconductor 2, the phenomenon of wear of the separation claw due to the gap does not occur.

As in this example, there is any difference in the degree of wear of the separation claw between the method of fixing the separation claw without moving it while the photoreceptor is rotating and the method of swinging the separation claw. The result of the experiment for investigating whether or not is shown in FIG.

In FIG. 12, the solid line represents the case without swinging,
The broken line shows the case where there is swinging. As can be seen from this example, the method of fixing the separating claw without swinging can reduce the wear of the contact width of the separating claw tip over time, leading to a defective image. It is possible to increase the number of sheets to be passed up to, that is, to extend the life of the separating claw.

[0055]

According to the present invention, it is possible to prevent the deterioration of the image quality due to the toner loss without damaging the image carrier by properly selecting the condition of the separating claw.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a separation claw.

FIG. 2 is a diagram illustrating a relationship between a wear width of a separation claw and a toner drop level.

FIG. 3 is a diagram illustrating a relationship between a wear width of a separation claw and the number of copies.

FIG. 4 is a diagram illustrating a relationship between the depth of a scratch given to an image carrier by a separation claw and the number of transferred sheets.

FIG. 5 is a diagram illustrating the shape of a separation claw before wear.

FIG. 6 is a diagram illustrating a shape of a separation claw after abrasion.

FIG. 7 is a view for explaining the position fixing means of the separation claw that can fix the position after position adjustment before the position adjustment.

FIG. 8 is a diagram for explaining the position fixing means of the separation claw capable of fixing the position after position adjustment, in a state after position adjustment.

FIG. 9 is a perspective view illustrating a position fixing means of the separation claw capable of fixing the position after position adjustment.

FIG. 10 is a cross-sectional view of an essential part of a position fixing unit of the separation claw that can fix the position after position adjustment.

FIG. 11 is a diagram illustrating the relationship between the movable range of the separation claw and the transfer paper size.

FIG. 12 is a diagram illustrating the relationship between the contact width and the number of copies when the separation claw is swung and fixed.

FIG. 13 is a front view of the separating claw and peripheral members for explaining the function of the separating claw.

FIG. 14 is a front view illustrating the initial contact state of the separation claw with the photoconductor.

FIG. 15 is a front view illustrating a contact state of the separation claw on the photoconductor after abrasion.

FIG. 16 is a plan view illustrating a state after the separation claw is worn.

FIG. 17 is a diagram illustrating the shape of a separating claw having a quadrangular cross section.

FIG. 18 is a diagram illustrating the shape of a separation claw having a circular cross section.

FIG. 19 is a diagram illustrating the relationship between the contact width of the separation claw and the width of the residual toner.

FIG. 20 is a diagram illustrating the relationship between the contact width of the separation claw and the width of the residual toner.

FIG. 21 is a front view illustrating a gap formed between the separation claw and the photoconductor when the separation claw is moving to the left.

FIG. 22 is a front view illustrating a gap formed between the separation claw and the photoconductor when the separation claw moves rightward.

FIG. 23 is a front view illustrating that there is no gap between the separation claw and the photoconductor when the separation claw is fixed.

[Explanation of symbols]

 2 separate nails

Claims (3)

[Claims] 1. A transfer paper separating device using a resin separating claw that abuts an image carrier and separates a transfer sheet, wherein a tip of the separating claw abutting the image carrier is a cone shape,
The angle between the tangent line of the image carrier and the separation claw contact surface at the separation claw contact point is α (°), the top projection weight angle of the separation claw is θ ₂ (°), the top projection tip of the separation claw The radius is R (μm), the projection weight angle of the separation claw in the rotation axis direction of the image carrier is θ ₁ (°), and the projection tip radius of the separation claw in the rotation axis direction is r (μ).
m), when _{a, 2tan (θ 2/2)} [R {1 / sin (θ 2/2) -
1} + r _{[cos (θ 1/2) /} tan {α + (θ 1 /
_{2)} - sin (θ 1} /2) +1 ] <meet _{200, θ 1, θ 2,} r, R, the transfer sheet separating device which is characterized by using a separation claw having a value of alpha. 2. The transfer paper separating device according to claim 1, wherein the separation claw has a material Rockwell hardness of H ≦ 109 (M scale). 3. The separation claw according to claim 2, wherein the separation claw is movable in the rotation axis direction of the image carrier and has means capable of being fixed so as not to move in the rotation axis direction. Transfer paper separating device characterized by.