JP2998526B2 - Fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device used in an image forming apparatus such as a printer, a video printer, a facsimile, and a copying machine. More specifically, the present invention relates to an improvement in a fixing device that uses an image support such as an envelope, passes a powder visible image formed on the image support between a heating member and a pressure member, and heats and fixes the image.

[0002]

2. Description of the Related Art A conventional fixing device is disclosed in
As described in JP-A-97169, paper wrinkles are caused by poor contact of the leading end of the image support with a heating roller or a pressure roller, or a measurement phenomenon, which results in poor supply of the image support between the two rollers. Was. In order to solve this problem, the outer diameter of both ends of the heating roller is made larger than the central part in the roller axial direction,
In addition, the position and angle of the paper supply guide are specified. However, although this technique was effective in preventing wrinkles on a single sheet, depending on the angle of the paper discharge guide, the use of an envelope causes wrinkles at the rear end of the envelope, and also causes flaps on side flaps. Displacement and wrinkles occurred.

In Japanese Patent Application Laid-Open No. S53-37432, a paper discharge guide is extended along a fixing member in order to prevent the paper from wrinkling, whereby the paper gradually separates from the fixing roller, and A fixing device that does not form a curve has been disclosed. This technique has the effect of preventing the paper from wrinkling. However, depending on the pressing force between the heating roller and the pressing roller and the angle of the paper supply guide, wrinkles were generated at the rear end of the envelope, and the flaps were displaced and wrinkled.

In Japanese Patent Application Laid-Open No. Sho 54-17034, in order to prevent the paper from being wound or wrapped around the heating roller, the angle of entry of the paper with respect to a straight line connecting both roller shafts is made obtuse. There has been disclosed a fixing device for increasing a peeling force by a saw. In this technique, there was an effect of preventing the paper from being wound around the heating roller.
However, depending on the angle of the paper discharge guide, wrinkles were generated at the rear end of the envelope, and the flaps were displaced and wrinkled.

Japanese Utility Model Laid-Open Publication No. Sho 56-69756 discloses a fixing device that regulates the angle at which the paper enters the nip between the rollers in order to prevent the paper from curling.
This is because the curl of the paper was caused by the paper separated from the nip by the peeling claw in a hot state. To solve this problem, the angle of entry of the paper with respect to the straight line connecting both roller shafts is made obtuse, the distance from the nip to the peeling claw is increased, and the paper cools before reaching the peeling claw. This technique was effective in preventing paper curl. However, depending on the paper discharge direction, wrinkles were generated at the rear end of the envelope, and the flaps were displaced and wrinkled.

As described above, in the above-described conventional fixing device, it is impossible to prevent wrinkles and flap displacement occurring on folded paper such as an envelope at the same time.

[0007] Also, US Patent No. 4,958,195
The cause of wrinkles in folded paper such as envelopes is that the first paper and the second paper gradually shift, and because the rear end of the paper is closed, the shift accumulates at the rear end of the paper, and the heating roller and the heating roller are heated. It is said that the wrinkles are crushed in the nip with the pressure roller. Therefore, in order to stably prevent wrinkling of folded paper, the pressure between the heating roller and the pressure roller is released at the rear end of the envelope in this US patent. Although this technique had the effect of preventing wrinkles at the rear end of the envelope, wrinkles were generated from the front end of the envelope to the center, and the fixing at the rear end of the paper was insufficient. Is indispensable, the number of parts is increased, the structure is complicated, and the apparatus is complicated and large, and the cost is high.

[0008]

When an envelope is fixed by a conventional fixing device, a bulge is generated at the rear end of the envelope, and the swelling is caused by crushing the bulge, and a flap is formed on the side of the envelope.
In many cases, slippage and wrinkles occurred. Further, in order to prevent wrinkles at the rear end of the envelope, there are problems that the apparatus is complicated and large, the cost is high, and the fixing at the rear end of the paper is insufficient.

An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide a high-quality printed matter which is stably free from wrinkles and flaps even when folded paper such as an envelope is used. It is an object of the present invention to provide a fixing device which can be obtained, is advantageous in miniaturization and cost reduction, and is capable of fixing up to the rear end of paper with a simple configuration.

[0010]

The fixing device according to the present invention comprises:
A front paper guide member disposed between the pair of heating members and the pressing members that abut against each other, and a front paper guide member disposed upstream of the pair of members with respect to a feed direction of the image support; In the fixing device, which is guided and conveyed by a rear paper guide member disposed downstream of the member, a softer member of the pair of members is defined as a first member, and the first member is formed on a central cross section of an image support width. A region where a pair of members are in contact is defined as a nip, and a midpoint between a point at an upstream end and a point at a downstream end of the nip in the image carrier transport direction is set as a reference point, and a point at the upstream end and the downstream are defined. A line connecting the end points is a reference line, and a line connecting the upstream end point of the front paper guide member and the reference point is a first line.
And a line connecting the point at the downstream end of the rear paper guide member and the reference point is a second line, and the first member is formed at an angle formed by the first line and the second line. Is defined as α, and α satisfies the following expression. −1 <F−24 × π × t × (1−α ÷ 180) ≦ 7 F; total load [Kgf] t; thickness of image support [mm] α; [corner] The front paper guide member and the rear paper guide member are each formed of a plate-shaped member. The fixing devices of the present invention press against each other.
An image support between a pair of heating members and a pressure member, a plate-shaped front paper guide member disposed upstream of the pair of members with respect to a feed direction of the image support, In the fixing device, which is guided and conveyed by a roller-shaped rear paper guide member disposed downstream of the member, a softer member among the pair of members is defined as a first member, and the first member is formed on a central cross section of an image support width. The nip is a region where the pair of members are in contact with each other, the midpoint of the upstream end point and the downstream end point of the nip in the image support transport direction is a reference point, and the point of the upstream end is A line connecting the point at the downstream end is a reference line, a line connecting the point at the upstream end of the plate-shaped front paper guide member and the reference point is a first line, and the roller-shaped rear paper is A line connecting the nip portion of the guide member and the reference point is a second line, and the first line
When the angle between the line and the second line and the angle including the first member is α, α satisfies the following expression. −1 <F−24 × π × t × (1−α ÷ 180) ≦ 7 F; total load [Kgf] t; thickness of image support [mm] α; [corner] An image support between a pair of a heating member and a pressurizing member that press against each other, a transfer unit disposed upstream of the pair of members with respect to a feed direction of the image support, and the pair of members In the fixing device, which is guided and conveyed by a roller-shaped rear paper guide member disposed on the downstream side, a softer member among the pair of members is defined as a first member, and the first member is formed on a central cross section of an image support width. The nip is a region where the pair of members are in contact with each other, the midpoint of the upstream end point and the downstream end point of the nip in the image support transport direction is a reference point, and the point of the upstream end is A line connecting the point at the downstream end is a reference line, and a line connecting the point at the downstream end of the transfer unit and the reference point is a second line. The lines, the roller-like a line connecting the nip portion and the reference point of the rear paper guide member and the second line, the in the first line and the second line is the angle between the first
When the angle including the member is α, α satisfies the following expression. −1 <F−24 × π × t × (1−α ÷ 180) ≦ 7 F; total load [Kgf] t; thickness of image support [mm] α; [corner] An image support between a pair of a heating member and a pressurizing member that press against each other, a transfer unit disposed upstream of the pair of members with respect to a feed direction of the image support, and the pair of members In the fixing device, which is guided and conveyed by a plate-shaped rear paper guide member disposed on the further downstream side, a softer member of the pair of members is replaced with a first member.
And a nip in a region where the pair of members are in contact with each other on the central cross section of the width of the image support, and a midpoint between a point at an upstream end and a point at a downstream end in the image support transport direction of the nip. A reference point, a line connecting the point of the upstream end and the point of the downstream end is a reference line, and a line connecting the point of the downstream end of the transfer unit and the reference point is a first line, A line connecting the nip portion of the plate-shaped rear paper guide member and the reference point is defined as a second line, and an angle formed by the first line and the second line includes an angle including the first member. When α is set, α satisfies the following expression. −1 <F−24 × π × t × (1−α ÷ 180) ≦ 7 F; total load [Kgf] t; thickness of image support [mm] α;

[0011]

[0012]

Next, a description will be given of the operation and mechanism for suppressing the wrinkling of the envelope by the above-described configuration.

A heating roller composed of a metal cylinder will be described as an example of a heating member, and a pressure roller having an elastic body formed around a metal shaft will be described as an example of a pressure member. Therefore, since the pressure roller is softer, it becomes the first member,
The heating roller is the second member. An envelope is taken as an example of the image support. As is well known, the envelope is mostly composed of two sheets, and the remaining part is overlapped with three or four sheets of paper, so that the envelope can be treated as two-fold paper.

When the envelope is passed between the heating roller and the pressing roller, the peripheral speed differs between the heating roller and the pressing roller, and the feeding amount is different. For this reason, a shift occurs between the first paper contacting the pressure roller and the second paper contacting the heating roller. However, since the first paper and the second paper are fixed to each other at the ends, the misalignment causes distortion and causes wrinkles.

Therefore, by appropriately bending the paper path upstream and downstream of the nip of both rollers, a shift opposite to the shift occurring in the nip is generated upstream and downstream of the nip, and the difference in feed amount is substantially reduced. If you lose it, there will be no deviation,
We have found that wrinkles do not occur.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of an image forming apparatus using a fixing device according to a specific embodiment of the present invention, in which a charging member such as a charging roller or a charging blade is attached to a photosensitive member 1 to be charged. 2 and then selectively irradiate the photoconductor 1 with light emitted from a light source 3 such as a laser or an LED according to an image to obtain a potential contrast, thereby forming a desired electrostatic latent image pattern. Form. On the other hand, the developing machine 4 conveys the toner 5 as an image forming body and develops the electrostatic latent image pattern.
Further, the transfer device 6 such as a transfer roller is used to transfer the toner image onto the image support 14 such as an envelope. Further, the conveying speed of the image support 14 to the fixing device 7 is 10 to 300 mm.
/ Second, and transports the toner 5 using heat or pressure to the image support 1.
4 and a desired image can be obtained on the image support 14.

The image support 14 is made of a single sheet or a double-folded sheet having no overlap. Here the folded paper is at least 2
The sheets of paper overlap and at least one end is closed,
For example, there is an envelope.

FIGS. 2 and 3 are schematic sectional views of a fixing device according to a specific embodiment of the present invention.

The terms “upstream” and “downstream” described below are directions with respect to the feed direction.

The fixing device shown in FIG. 2 includes a pressure roller 12, a heating roller 11, and a front paper guide member 20 as a member for guiding paper disposed upstream of the nip, and a member for guiding paper disposed downstream of the nip. A rear paper guide member 21 is provided.

The fixing device of FIG. 3 is the same as the fixing device of FIG. 2 except that the front paper guide member 20 is omitted and the rear paper guide member is constituted by rollers 22.

The heating roller 11 is made of a metal cylinder having good heat conductivity, such as aluminum, and its surface is coated with a fluorine resin or the like so that paper, toner and the like are easily peeled off. The outer diameter used was 10 to 30 mm. Also, the heating roller 11
The outer diameter of the central portion and the outer diameter of the end portion in the axial direction may be changed as necessary. A halogen lamp or the like is disposed inside as a heat source. The surface temperature of the upper part of the heating roller is measured by a temperature detector (not shown), and the heat source is turned on based on the surface temperature.
・ Turn off and always control to the set temperature.

Generally, the surface temperature of the heating roller is 120 ° C.
Below, the fixing is incomplete and the toner peels from the paper,
Only low quality printed matter can be obtained. Further, when the surface temperature of the heating roller was higher than 190 ° C., the paper was scorched or deteriorated, and only low-quality printed matter was obtained. At higher temperatures, ignition can occur and is dangerous. Therefore, the surface temperature of the heating roller is preferably 190 ° C. or less. Therefore, in this embodiment, the surface temperature of the heating roller at the time of fixing is 120 to 190.
It was a constant temperature in the range of ° C.

Further, if necessary, a cleaner such as an oil impregnated pad may be brought into contact with the surface of the heating roller.

The pressure roller 12 is formed by forming an elastic body such as silicon rubber around a metal shaft 13 such as steel or stainless steel by injection molding or the like. It is preferable that the elastic body has a small compression set and has a resistance such as not to be fused to the toner. Outer diameter is 8-30
mm and a hardness of 16 to 60 degrees according to JIS-A. The outer diameter of the pressure roller 12 at the center in the axial direction and the outer diameter at the end may be changed as necessary. Further, it is pressed against the heating roller by a load means (not shown).

Therefore, in this embodiment, the pressing roller is softer than the heating roller, so that the pressing roller is the first member and the heating roller is the second member.

The angle at which the paper enters the pressure roller 12 is regulated by the front paper guide member 20, and the discharge angle is regulated by the rear paper guide member 21. The paper guide members 20 and 21 are formed as plate-like members as shown in FIG. The paper guide member may be constituted by a member having irregularities or a rib. Further, the rear paper guide member may be constituted by rollers 22 as shown in FIG. Also,
The front paper guide member 20 can be omitted. At this time, the paper separated from the transfer unit enters the fixing device due to the stiffness of the paper (paper strain).

FIG. 2 is a central sectional view of the width of the image support.
Is used to define α.

First, components for defining α will be described.

The area where the heating roller and the pressure roller are in contact on the central section of the width of the image support is defined as a nip. A line connecting the point P1 at the upstream end of the nip and the point P2 at the downstream end is defined as a reference line L3, and the reference point NP is defined as a middle point of the segment P1P2. Of the lines connecting the point on the path through which the image support passes upstream of the nip and the reference point NP, the line having the maximum acute angle with the reference line L3 is defined as a first line L1, and the first line L1 and the path Is P3. Also, among the lines connecting the point on the path through which the image support passes downstream of the nip and the reference point NP, the reference line L3
Is the second line L2, and the line at which the acute angle between
The intersection of the line L2 and the route is P4. Further, the approach angle β [degree] and the discharge angle γ [degree] are respectively the first line L1
Alternatively, an acute angle is formed between the second line L2 and the reference line L3, and the pressure roller side as the first member is in the minus direction.

[Alpha] [degree] is defined by the above components as follows.

Α is an angle formed by the first line L1 and the second line L2, and is an angle including the first member. At this time, α becomes 180 = β + γ.

In this embodiment, α is determined as described above. However, when it is difficult to determine α by the above method, the first line L1 is a line connecting the point at the upstream end of the front paper guide member 20 to the reference point NP, and the second line L2 is the line of the rear paper guide member 21. Since the value of α substantially coincides with a line connecting the point at the downstream end and the reference point NP, α is determined. For example, when the rear paper guide member is constituted by the roller 22 as shown in FIG. 3, if the second line L2 is a line connecting the reference point NP and the nip portion P5 of the roller 22, α is determined.

Further, as shown in FIG.
If the first line L1 is a line connecting the reference point NP and the point P6 at the downstream end of the transfer portion, the value of α substantially coincides, and therefore α is determined.

Hereinafter, detailed examples using various envelopes will be described in Experimental Examples 1 to 4.

(Experiment 1) As shown in FIG. 2, the fixing device used in this experiment mainly comprises a heating roller, a pressure roller, a front paper guide member, and a rear paper guide member.
The heating roller is made of an aluminum cylinder having a diameter of 18 mm and a thickness of 0.6 mm, and its surface is coated with a fluororesin. A halogen lamp of 400 W is arranged inside. The pressure roller formed a silicone rubber around the steel shaft 13 by injection molding. Outer diameter of pressure roller is φ
The outer diameter of the shaft was 10 mm and the thickness of the rubber was 4 mm. The hardness of this rubber is 23 degrees (JIS-A)
And In addition, the temperature of the upper part of the heating roller is measured by a temperature detector, and the temperature is set at 150 ° C. based on the surface temperature.
Was controlled. The heating roller was driven at a peripheral speed of 23 mm / sec by a driving unit (not shown).

In this experimental example, a Strathmore envelope (O
ld Colony). Assuming that t is the thickness of the paper constituting the envelope, t of the Strathmore envelope is 0.13 m.
m.

Using this fixing device, printing is performed by changing the entrance angle β and the discharge angle γ of the envelope to the nip portion between the heating roller and the pressure roller, and changing the total load of the roller to evaluate wrinkles and flap deviations. did.

Tables 1 to 9 show the results of evaluating the wrinkles of the print samples. Tables 1 to 9 have a vertical approach angle β and a horizontal discharge angle γ. Tables 1 to 9 show that the total load is 2 kgf, 3 kgf, 4 kgf, 5 kgf, respectively.
6kgf, 7kgf, 8kgf, 9kgf, 10kgf
The evaluation in is shown. In the table, ○ indicates that there is almost no wrinkle and there is no flap deviation, Δ indicates that there is a wrinkle of less than 3 cm and no flap deviation, and X indicates that there is a wrinkle of 3 cm or more and flap deviation. . In addition,-was the condition which did not perform an experiment.

As can be seen from Tables 1 and 2, the total load is 2 k
With gf and 3 kgf, no wrinkles or flap deviations occurred in the envelope. However, as can be seen from Tables 3-9, 4 kg
A wrinkle was generated depending on the approach angle β or the discharge angle γ at a total load of f or more. When the total load was further increased, several wrinkles of 3 cm or more were generated, and a flap displacement occurred. Also,
Even with the same total load, the sum of the entry angle β and the discharge angle γ
The condition of wrinkles has changed.

Then, using the aforementioned α (= 180 + β + γ) and the total load F, the occurrence of wrinkles and flap deviations is shown in Table 1.
0.

As shown in Table 10, when α was 190 degrees and the total load was 3 kgf or less, there were almost no wrinkles and there was no flap displacement. When α is 190 degrees and the total load is 6 kgf
Below, there was no wrinkle of 3 cm or more, and no flap displacement. When α is 180 degrees or less and the total load is 4 kgf
Below, there were almost no wrinkles and no flap deviation.

When the total load is greater than 4 kgf, wrinkles and flap misalignment may occur. However, the presence or absence of wrinkles, the degree of wrinkle and the presence of flap misalignment depend on α, and the smaller α is preferable. It became. The reason was examined as follows.

FIG. 4 is a conceptual diagram showing a fixing device of the present invention, and is an enlarged view of a main part of the fixing device. The numbers in the figure are the same as in FIG. Reference numeral 11 denotes a heating roller.
Reference numeral 12 denotes a pressure roller which forms an elastic body around a metal shaft 13. The image support 14 is an envelope, which enters the nip region N of both rollers from the right side as shown by the arrow in the figure, and is discharged to the left side in the figure. The image support 14 has a first paper 15 contacting the pressure roller and a second paper 16 contacting the heating roller.
And Further, B is a region from the contact of the pressure roller 12 and the image support 14 on the entrance side of the image support 14 to the entrance of the image support 14 to the nip region N, and C is a discharge side of the image support 14 in the nip region N. The area from the exit to the separation from the pressure roller 12 is shown.

In the nip region N, the image support 14 becomes convex downward, and the first paper 15 is conveyed longer than the second paper, causing a shift. The amount by which the second paper 16 and the first paper 15 are displaced from the time when the image support 14 enters the nip area N to the time when the image support 14 exits is represented by Δd1.
And F is the pressing force of the pressure roller 12 against the heating roller 11 (hereinafter referred to as total load). When F is increased, the pressure roller is elastically deformed according to its elastic coefficient k0 [kgf / mm], and the nip width NL [mm] increases. In the load range that we confirmed through the experimental examples, F and NL were in a proportional relationship. On the other hand, since the displacement between the first paper and the second paper occurs in the nip, the displacement △ d1 [mm] is proportional to the nip width NL.
Therefore, the following relationship holds for the deviation amount Δd1.

[0047]

(Equation 3)

Here, k1 and k2 are proportional constants and are dimensionless.

Introducing the proportional constant; k3≡k1 × k2 ÷ k0 [mm / kgf], equation (4) can be rewritten as Δd1 = k3 × F.

Next, in the areas B and C, the image support 14 becomes convex upward, and the second paper 16 is transported longer than the first paper 15. The total paper shift amount in the areas B and C is △ d2.

FIG. 5 is a conceptual diagram in the case where two sheets of paper are placed along the pressure roller. The image support 14 is a pressure roller 1
The angle from the contact of the image support 14 to the separation thereof is θ, and the angle between the tangent at the contact point P7 on the entrance side of the image support 14 and the tangent at the contact point P8 on the discharge side is η. Therefore, θ = 1
80- [eta].

It should be noted that α described in the present invention is substantially the same as η in this experimental example, and η is used in this experimental example to indicate a basic model that is a wrinkle suppressing mechanism. However, even if α is used, the wrinkle suppression mechanism is the same.

L4 is the center line of the first paper, and L5 is the center line of the second paper. The line perpendicular to the tangent at P7 and P
Lengths of L4 and L5 cut by a tangent line at 8 and a line orthogonal to L8 are denoted by l1 and l2, respectively. l1 and l2 are respectively given by the following equations. However, the radius of the pressure roller is R,
The thickness of the paper constituting the image support was defined as t.

L1 = 2π × (R + 0.5 × t) × (θ ÷ 360) l2 = 2π × (R + 1.5 × t) × (θ ÷ 360) Here, the shift amount in the regions B and C is ( l2-l1). That is, △ d2 is calculated using the dimensionless proportional constant k4,

[0055]

(Equation 4)

Is as follows.

Here, if Δd1 ≒ △ d2, the displacement of the paper in the area N is offset by the areas B and C, and the displacement of the paper is substantially eliminated, and no wrinkles occur.

Therefore, the condition under which the envelope serving as the image support is free from wrinkles is as follows.

[0059]

(Equation 5)

Is as follows. Here, if A≡k4 ÷ k3 [kgf / mm], equation (6) becomes

[0061]

(Equation 6)

Is obtained.

Here, α and η are substantially the same, so that equation (7)
Is

[0064]

(Equation 7)

Can be expressed as follows.

As a result of examining the experimental results shown in Table 10 from the viewpoint of equation (7 '), the best agreement was obtained when A = 24 [kgf / mm]. However, in the equation (7 '), even when the total load is small, there is an angle dependency, and a part that does not match the experimental result appears. Therefore, the inventors further studied the experimental results and found that it would be better to add the following correction.

[0067]

(Equation 8)

Next, the correction number a will be described.

The shift Δd 1 in the nip area N is generated by the frictional force between the paper and the pressure roller, that is, the conveying force, and the frictional force is proportional to the total load. Under a certain total load, it is considered that the drag due to the breakage of the paper edge overcomes the conveyance force. From the experimental results, when α = 180 °, no severe wrinkling occurred even if the sheet was conveyed while being sandwiched by the nip with a total load of 4 kgf. This is considered to be because the effect due to the folding of the paper edge overcomes the frictional force between the paper and the pressure roller, and the amount of deviation can be suppressed to a certain level that does not cause wrinkles. Therefore, up to a certain amount of deviation, the bending hardness of the paper prevails, and no wrinkles occur. It is assumed that the correction term for this is a.

By transforming equation (8),

[0071]

(Equation 9)

Is obtained. Table 11 shows the result obtained by calculating a corresponding to Table 10 from Equation (9). As a result, we have found that the range of a in which wrinkles of 3 cm or more do not occur is −1 <a ≦ 7. Therefore, a is preferably -1 <a ≦ 7.

From the above, we have found that when α satisfies the following equation (10), there is no wrinkle or flap deviation in the envelope and high quality printing can be obtained.

[0074]

(Equation 10)

As described above, we have found that the difference in the feed amount between the first paper and the second paper in the envelope is proportional to the thickness of the paper and the total load of the rollers, and does not cause wrinkles or flap misalignment in the envelope. It was found that a proper bending angle was necessary for this.

That is, by setting the bending angle, ie, α, in the range of the expression (10) with respect to the thickness of the paper and the total load of the roller, even if an envelope is used, the angle between the first paper and the second paper can be substantially reduced. It has been found that high quality printed matter free from wrinkles and flap deviations is obtained stably without any deviation.

[0077]

[Table 1]

[0078]

[Table 2]

[0079]

[Table 3]

[0080]

[Table 4]

[0081]

[Table 5]

[0082]

[Table 6]

[0083]

[Table 7]

[0084]

[Table 8]

[0085]

[Table 9]

[0086]

[Table 10]

[0087]

[Table 11]

(Experimental Example 2) In this experimental example, the same experiment as in Experimental Example 1 was performed except that the type of envelope used was different. In this experimental example, an airmail envelope (made by KIRK) having a thin paper thickness t of 0.08 mm was used.

In the same manner as in Experimental Example 1, the printing angle was changed by changing the entrance angle β and the discharge angle γ of the paper into the nip portion between the heating roller and the pressure roller, and changing the total load of the roller. evaluated. Tables 12 to 1 show the evaluation results.
It is shown in FIG.

Tables 12 to 19 take the paper entry angle β vertically and the discharge angle γ horizontally, and each has a total load of 2 kg.
f, 3kgf, 4kgf, 5kgf, 6kgf, 7kg
The evaluation at f, 8 kgf, and 9 kgf is shown. Evaluation criteria were the same as in Experimental Example 1.

As can be seen from Tables 12 to 14, no wrinkles or flap deviations occurred in the envelope when the total load was 2 kgf to 4 kgf. However, as can be seen from Tables 15 to 19, wrinkles are generated depending on the approach angle β or the discharge angle γ at a total load of 5 kgf or more, and when the total load is further increased, several wrinkles of 3 cm or more are generated, and the flap misalignment is caused. There has occurred. In addition, even with the same total load, the occurrence of wrinkles changed depending on the sum of the approach angle β and the discharge angle γ.

Then, using the above α (= 180 + β + γ) and the total load F, the occurrence of wrinkles and flap deviations is shown in Table 2.
0.

As shown in Table 20, when α was 190 degrees, there was almost no wrinkle under a total load of 4 kgf or less, and there was no flap displacement. When α is 190 degrees, the total load is 6 kg.
Below f, there were no wrinkles of 3 cm or more, and no flap deviation.

When α is 180 degrees or less, the total load 4
At less than kgf, there were almost no wrinkles and no flap deviation. Also, when the total load is greater than 4 kgf,
The presence or absence of wrinkles, the degree of wrinkles, and the presence or absence of flap displacement depend on α, and the smaller α is more preferable. When the total load is 8 kgf and α is 160 degrees or more, 3 cm
Several wrinkles described above occurred, and 2-3 were found on the flap side end.
Many wrinkles of mm occurred. However, even at the same 8 kgf, when α was 150 degrees or less, only light wrinkles were observed, and there was no flap deviation.

Therefore, even when a thin airmail envelope is used, the condition that there is almost no wrinkle and there is no flap deviation is in the range of the expression (10), and this expression was effective even when using different types of envelopes.

[0096]

[Table 12]

[0097]

[Table 13]

[0098]

[Table 14]

[0099]

[Table 15]

[0100]

[Table 16]

[0101]

[Table 17]

[0102]

[Table 18]

[0103]

[Table 19]

[0104]

[Table 20]

(Experimental Example 3) In this experimental example, using the fixing device shown in FIG. 6 or FIG. Wrinkles and flap deviations were examined.

FIG. 6 is a schematic cross-sectional view of the fixing device used in Example 3 of the present invention. The heating roller has an outer diameter of φ30 mm and a thickness of 1.5 mm
A halogen lamp of 500 W was arranged inside, and the temperature was constantly controlled at 170 ° C. Outer diameter of pressure roller is φ26mm
The outer diameter of the shaft was 12 mm, the thickness of the rubber was 7 mm, and the hardness of the rubber was 60 degrees (JIS-A). Also,
Both rollers were pressed against each other with a total load of 7 kgf, and the heating roller was driven at a peripheral speed of 120 mm / sec. A Strathmore envelope (manufactured by Old Colony) was used. The thickness t of the paper constituting this envelope was 0.13 mm.

First, printing was performed by a conventional fixing device in which the entrance angle β was set to +10 degrees by the front paper guide member 31 and the discharge angle γ was set to 0 degrees by the rear paper guide member 33. At this time, α was 190 degrees. As a result of printing, wrinkles of 3 cm or more are generated in the envelope, there is a flap deviation,
Poor quality prints were obtained.

Next, printing was performed by the fixing device of the present invention in which the entering angle β was set to −20 degrees by the front paper guiding member 32 and the discharging angle γ was set to −30 degrees by the rear paper guiding member 34. At this time, α was 130 degrees. As a result of printing, there was no wrinkle in the envelope, no flap deviation, and a high quality printed matter was obtained.

FIG. 7 is a schematic sectional view of the fixing device used in Example 3 of the present invention. The heating roller had an outer diameter of 20 mm and a wall thickness of 1 mm, and a halogen lamp of 400 W was disposed inside the heating roller, and the temperature of the heating roller was constantly controlled at 130 ° C. The pressure roller has an outer diameter of φ16 mm, a rubber thickness of 3 mm, and a rubber hardness of 20 degrees (JI
SA). Both rollers were pressed against each other with a total load of 5 kgf, and the heating roller was driven at a peripheral speed of 60 mm / sec.

An airmail envelope (made by KIRK) was used. The thickness t of the paper constituting this envelope was 0.08 mm.

First, printing was performed by a conventional fixing device in which the paper entry angle β was set to +30 degrees by the front paper guide member (not shown) and the discharge angle γ was set to +30 degrees by the rear paper guide member 33. At this time, α was 240 degrees. As a result of printing, wrinkles of 3 cm or more were generated in the envelope, flap deviation occurred, and a printed matter of poor quality was obtained.

Next, the paper entry angle β is determined by the front paper guide member 3.
2, and the discharge angle γ is set at the rear paper guide member 3.
The printing was performed by the fixing device of the present invention in which the temperature was set to −20 degrees according to Example 4. At this time, α was 140 degrees. As a result of printing, there was no wrinkle in the envelope, no flap deviation, and a high quality printed matter was obtained.

From the experiments described above, if the outer diameter of the heating roller, the outer diameter of the pressing roller, the hardness of the pressing roller, the surface temperature of the heating roller, and the paper feed speed are changed, wrinkles and flap displacement of the envelope occur. The situation changes, but α is given by equation (10)
It can be confirmed that, when it is within the range, no occurrence occurs as in Experimental Examples 1 and 2.

In general, a fixing device has a configuration in which a pressure roller is pressed against a heating roller to secure a contact nip, and the shaft of the heating roller and the pressure roller is deformed by this pressing force, and the central portion of the roller is deformed. Then, the nip is small, and the nip becomes large at both ends. Conventionally, when fixing a single sheet of paper, a configuration is adopted in which a heating roller is provided with an inverted crown to increase the paper feeding speed at both ends of the single sheet to increase wrinkles. This was a factor that significantly changed the distribution in the roller axis direction.

In Experimental Examples 1 and 2, when the total load was large, the envelopes tended to wrinkle and flap misalignment. I checked.

(Experimental Example 4) In this experimental example, two types of fixing devices were used. The configuration is shown below.

The fixing device A has an outer diameter of the heating roller of φ18 m.
m, the thickness is 0.6 mm, and the outer diameter of the pressure roller is φ
18, the rubber thickness was 2 to 5 mm, and the total load was 4 to 8 kgf. Further, the entrance angle β is set to −10 degrees, and the discharge angle γ is set to 0.
Degrees, α = 170 degrees.

The fixing device B has an outer diameter of the heating roller of φ20,
The thickness was 2 mm, the outer diameter of the pressure roller was φ16.5, the rubber thickness was 2 to 4 mm, and the total load was 4 to 8 kgf. The entrance angle β is −10 degrees, the discharge angle γ is −30 degrees, α
= 140 degrees.

Here, when the image support passes through the nip of the fixing device, the minimum nip width at the position where the image support passes is Nmin, the maximum nip width is Nmax, and Nmax / Nm
in is the nip ratio. In this experimental example, the nip ratio is used as the nip width distribution, and the paper passing position in the roller axis direction, the total load, the thickness, and the rubber hardness of the pressure roller are changed, and a Strathmore envelope (Old Colony, paper thickness t is 0) .13m
m), wrinkles were evaluated. A substantially central portion of the roller of the fixing device in the axial direction is simply referred to as a roller central portion, and a substantially end portion of the roller in the axial direction is referred to as a roller end. The direction of the roller axis is defined as the width direction of the envelope, the center of the envelope in the width direction is simply referred to as the center of the envelope, and the end of the envelope in the width direction is referred to as the end of the envelope.

The following 1) to 9) show the experimental results.

1) In the fixing device A, when the thickness of the pressure roller is 4 mm, the hardness is 23 degrees, the total load is 5 kgf, and when the envelope is passed through with the center of the envelope aligned with the center of the roller, Nmax is 2 .25 mm, Nmin was 2.10 mm, and the nip ratio was 1.07. At this time, the envelope had no wrinkles and no flap displacement.

2) When the same pressure roller is used in the fixing device A and the total load is 6 kgf at the same sheet passing position, Nmax is 2.41 mm, Nmin is 2.26 mm, and the nip ratio is 1.07. Met. At this time, the envelope had no wrinkles and no flap displacement.

3) In the fixing device A, when the same pressure roller is used, the same paper passing position and the total load are 7 kgf, Nmax is 2.52 mm, Nmin is 2.31 mm, and the nip ratio is 1.09. Met. At this time, the envelope had no wrinkles and no flap displacement.

4) In the fixing device A, when the same pressure roller is used, the total load is set to 5 kgf, and the envelope is passed through with the end of the envelope aligned with the end of the roller, the Nmax is 2.63 m.
m and Nmin were 2.10 mm, and the nip ratio was 1.25. At this time, there was no flap displacement in the envelope, but 3
There were wrinkles of less than cm.

5) In the fixing device A, when the same pressure roller is used at the same sheet passing position and the total load is 6 kgf, Nmax is 2.82 mm, Nmin is 2.26 mm, and the nip ratio is 1.25. Met. At this time, the envelope had no flap displacement, but had wrinkles of less than 3 cm.

6) In the fixing device A, when the same pressure roller is used at the same sheet passing position and the total load is 7 kgf, Nmax is 3.10 mm, Nmin is 2.31 mm, and the nip ratio is 1. 34. At this time, the envelope had no flap displacement, but had wrinkles of less than 3 cm.

7) In the fixing device B, the pressure roller had a thickness of 3.5 mm and a total load of 4 kgf. Nmax was 2.03 mm, Nmin was 1.92 mm, and the nip ratio was 1.06 when the envelope was passed through with the center of the envelope aligned with the center of the roller. At this time, the envelope had no wrinkles and no flap displacement.

8) In the fixing device B, the pressure roller had a thickness of 3.5 mm and a total load of 5 kgf. When the envelope is passed with the edge of the envelope aligned with the edge of the roller, Nmax is 2.
70 mm, Nmin is 2.00 mm, nip ratio is 1.3
It was 5. At this time, wrinkles of 3 cm or less occurred in the envelope.

9) In the fixing device B, when the thickness of the pressure roller is 4.0 mm, the total load is 8 kgf, and when paper is passed at the same position, Nmax is 3.23 mm and Nmin is 2.00 mm.
The nip ratio was 1.62. At this time, the envelope had wrinkles of 3 cm or more, and further a flap deviation occurred.

Hereinafter, similar experiments were conducted, and Table 21 summarizes the results. The evaluation criteria were the same as those in Experimental Example 1.

[0131]

[Table 21]

From Table 21, it was found that when the nip ratio was larger than 1.5, severe wrinkling occurred and flap deviation occurred. When the nip ratio is larger than 1.2 and equal to or smaller than 1.5, there is no flap deviation, but there is a tendency for slight wrinkles to occur. When the nip ratio was 1.2 or less, there was no tendency to wrinkle and no flap displacement.

This can be explained as follows.

When the nip width is different in the axial direction, when two sheets of the first sheet and the second sheet overlap each other and pass through the nip like an envelope, the deviation amount of the first sheet and the second sheet is expressed by: d1 changes in the roller axis direction with the distribution of the nip width. Since Δd2, which compensates for this, is substantially constant irrespective of the axial distribution of the nip width, a difference in the amount of displacement between the first paper and the second paper occurs in the axial direction of the roller, and as a result, wrinkling occurs. In some cases, it cannot be prevented. Also, since the feeding speed in the width direction of the envelope is different, the margin for gluing (the flap) of the envelope is different from the first paper and the second paper.
Flaps which are shifted between the sheets of paper.

In addition, when the paper was passed while the edge of the envelope was aligned with the edge of the roller, wrinkles tended to occur. This is because when one end of the envelope is passed through the roller end, the other end of the envelope passes through the center of the roller, so that the nip width at the roller end is Nma.
x, the nip width at the center of the roller is Nmin, and as described above, the nip width is small at the center of a general roller, and the nip width is large at both ends. It is.

Conversely, when the envelope is passed with the central portion of the envelope aligned with the central portion of the roller, the nip width at the position where one end and the other end of the envelope pass is substantially equal to Nmax, and the nip width at the central portion of the roller is Nmax. This is because the width becomes Nmin and the nip ratio approaches 1, so that no paper displacement occurs.

Further, when the total load was large, wrinkles tended to occur. This is because when the total load increases, the nip ratio also increases accordingly, the difference in the above-described shift amount increases, flap shift occurs, and wrinkles occur.

Therefore, as described above, in order to prevent the envelope from wrinkling and flap displacement, the nip ratio should be set to 1.5 for the nip ratio determined by the paper passing position, the total load, the shape of the heating roller, the hardness of the pressure roller, and the like. 1.2
In the following case, wrinkles and flap deviations of the envelope are not seen at all, which is more preferable.

Similarly, in order to make the nip ratio close to 1 and eliminate wrinkles, it is preferable to pass the paper with the center of the envelope aligned with the center of the roller.

In the foregoing, wrinkles and flap deviations of folded paper such as envelopes have been described. In addition, it is preferable that wrinkles do not occur on a single sheet of paper. Further, since the conditions of the total load and the sheet passing angle described so far greatly affect the occurrence of curling, next, wrinkles and curling of envelopes and single sheets will be examined in detail.

(Experimental Example 5) The same experiment as in Experimental Example 1 was performed by using β and γ and the total load, and using an envelope or a single sheet of paper, to evaluate wrinkles and curls.

As one sheet of paper, NBS PAPER (manufactured by Japan Business Supply Co., Ltd., thickness of 0.08 mm), which is apt to wrinkle, was used. Envelopes are Strathmore envelopes (Old Colony, paper thickness t is 0.13 mm) and airmail envelopes (KIRK, paper thickness t is 0.08 mm)
Was used.

First, when the wrinkles of one sheet were evaluated, the total load was 2 kgf to 10 kgf, and the entry angle β of the paper was −4 kgf.
When it is 0 degrees or more and 0 degrees or less, there is a tendency that wrinkles do not occur on one sheet of paper. On the other hand, wrinkles occurred when β was greater than 0 degrees. This is because the paper comes into contact with the heating roller before entering the nip of the fixing device and receives heat, so that a wave-like wrinkle is generated. When the paper enters the nip, the paper is folded and becomes wrinkled. On the other hand, wrinkles also occurred when β was less than −40 degrees. This is because the paper does not smoothly enter the nip, so that the paper is distorted and wrinkled. Therefore, when the entrance angle β is −40 degrees ≦ β ≦ 0 degrees in the fixing device of the present invention, not only does the envelope not have wrinkles and flap deviations but also tends to have no wrinkles on one sheet.

Next, when the curl of the envelope and the single sheet was evaluated, when the total load was 2 kgf to 10 kgf and the discharge angle γ was lower than −10 degrees, the paper remained bent toward the pressure roller so-called reverse. Curling occurs on envelopes and single sheets, and +
When the temperature is higher than 10 degrees, a so-called regular curl in which the bending toward the heating roller remains is generated. The reason for this is that the paper is bent before it cools, leaving the hot shape on the paper. Therefore, in the fixing device of the present invention, the discharge angle γ is set to −10 degrees ≦
When γ ≦ + 10 degrees, not only does the envelope not generate wrinkles or flap misalignment, but also no curl occurs between the envelope and one sheet of paper.

From these facts, the entry angle β is set to −40 degrees ≦ β ≦ 0 degrees, and the discharge angle γ is set to −10 degrees ≦ γ ≦ + 1.
By setting the angle α to 0 degree, that is, by setting the range of α to 130 ≦ α ≦ 190, no wrinkles occur on one sheet of paper, and
Curling of the sheet can be prevented.

Further, when α, β, and γ were set in the above ranges, the influence of the total load was examined.

When the total load F was less than 2 kgf, there was no wrinkle or flap displacement in the envelope if α satisfied Expression (10). However, if it is less than 2 kgf, the paper may not be smoothly transported, causing image disturbance and printing with poor image quality. Therefore, the total load is preferably 2 kgf or more.

When an airmail envelope (manufactured by KIRK) was used, wrinkles were the same as those in Table 20 of Experimental Example 2, and wrinkles occurred at 9 kgf or more. Therefore, α,
β and γ are within the above ranges, and the total load F is 2 kgf ≦ F
If it is <9 kgf, no wrinkles are generated on the single sheet, no curl is generated on the envelope and the single sheet, no image disturbance is generated, and no wrinkles are generated on the envelope.

Further, when one sheet of paper is used, the total load is 4
The wrinkles were further reduced at kgf or more. Further, when a higher fixing strength is desired, the total load should be 4 kgf or more. Therefore, if the total load F is set to 4 kgf ≦ F <9 kgf in the fixing device of the present invention, not only does the envelope not generate wrinkles and flap misalignment, but also wrinkles do not occur even when one sheet of paper which is likely to generate wrinkles is used. And higher fixing strength can be obtained.

The results of Experimental Example 5 can be summarized as follows: 1) When −40 degrees ≦ β ≦ 0 degrees, there is no wrinkle or flap deviation in the envelope, and no wrinkles occur on one sheet of paper.

2) When −10 degrees ≦ γ ≦ + 10 degrees, there is no wrinkle or flap deviation in the envelope, and no curl occurs between the envelope and one sheet of paper.

3) When 130 ≦ α ≦ 190, there is no wrinkle or flap deviation in the envelope, and no wrinkles occur on one sheet of paper.
In addition, no curl occurs on the envelope and the single sheet.

4) When the total load is 2 kgf or more, there is no image disturbance, and there is no wrinkle or flap displacement in the envelope.

5) When the total load F is 2 kgf ≦ F <9 kgf, there is no wrinkle or flap deviation in the envelope, no wrinkles on one sheet, and no curl on the envelope and one sheet.
No image disturbance occurs.

6) When the total load F is 4 kgf ≦ F <9 kgf, there is no wrinkle or flap deviation in the envelope, no wrinkles are generated even when one sheet of paper is used, and a stronger fixing strength is obtained.

The present invention has been described with reference to the embodiments.
As is clear from the principle of preventing wrinkles of the present invention, fixing using a square fixing member or a curved fixing member or a thin belt as a heating member and a pressing member, and using a rod-shaped resistance heating element as a heat source. Even if the present invention is applied to the apparatus, it is possible to reduce wrinkles and flap deviations of the envelope.

[0157]

As described above, according to the present invention, there is no wrinkle from the front end to the rear end, no flap displacement, even when using two-fold paper having a margin at the end such as an envelope. Fixing can be performed reliably to the trailing edge of the paper, and high-quality printed matter can be obtained.
In addition, a fixing device that is advantageous for downsizing and cost reduction can be obtained.

Further, according to the present invention, the fixing property of the toner is good, the printed matter has no curl, and wrinkles do not occur even when a single sheet of paper having no margin at the end is passed.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an image forming apparatus using a fixing device according to a specific embodiment of the present invention.

FIG. 2 is a schematic diagram of a fixing device according to a specific embodiment of the present invention, and is a central cross-sectional view of an image support width.

FIG. 3 is a schematic sectional view of a fixing device according to a specific embodiment of the present invention.

FIG. 4 is a conceptual diagram illustrating a fixing device of the present invention.

FIG. 5 is a conceptual diagram in a case where two sheets of paper are placed along a pressure roller.

FIG. 6 is a schematic cross-sectional view of an experimental example using a fixing device according to a specific embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view of one experimental example using a fixing device according to a specific embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor 2 charging member 3 light source 4 developing device 5 toner 6 transfer device 7 fixing device 11 heating roller 12 pressure roller 13 shaft 14 image support 15 first paper 16 second paper 20 front paper guide member 21 Rear paper guide member 22 Roller for rear paper guide member 31 Conventional front paper guide member 32 Front paper guide member of the present invention 33 Conventional rear paper guide member 34 Rear paper guide member of the present invention

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Kazuo Yoda 3-5-2-5, Yamato, Suwa-shi, Nagano Seiko Epson Corporation (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 13 / 20 G03G 15/20

Claims (10)

(57) [Claims] 1. A front paper guide in which an image support is disposed between a pair of a heating member and a pressurizing member which are pressed against each other and is located upstream of the pair of members with respect to a feed direction of the image support. A fixing member that is guided and conveyed by a rear paper guide member disposed downstream of the pair of members, wherein a softer member of the pair of members is defined as a first member; A region where the pair of members are in contact with each other on a central cross section is defined as a nip, and a midpoint between a point at an upstream end and a point at a downstream end of the nip in an image support conveying direction is set as a reference point, and the upstream end is And a line connecting the point at the upstream end of the front paper guide member and the reference point is defined as a first line, and a line connecting the point at the upstream end of the front paper guide member is defined as a first line. A line connecting the downstream end point and the reference point is defined as a second line, and the first line and the second line are connected to each other. When the corner including the at angle line of the first member and alpha, fixing device alpha is to satisfy the following equation. −1 <F−24 × π × t × (1−α ÷ 180) ≦ 7 F; total load [Kgf] t; thickness of image support [mm] α; 2. The fixing device according to claim 1, wherein the front paper guide member and the rear paper guide member are each formed of a plate-shaped member. 3. A plate-shaped front in which an image support is disposed between a pair of a heating member and a pressurizing member that are pressed against each other and is located upstream of the pair of members with respect to a feed direction of the image support. In a fixing device that is guided and conveyed by a paper guide member and a roller-shaped rear paper guide member disposed downstream of the pair of members, a softer member among the pair of members is a first member. An area where the pair of members are in contact with each other on the central cross section of the image support width is defined as a nip, and a midpoint between an upstream end point and a downstream end point of the nip in the image support transport direction is a reference point. A line connecting the point of the upstream end and the point of the downstream end is a reference line, and a line connecting the point of the upstream end of the plate-shaped front paper guide member and the reference point is a first line. A line connecting the nip portion of the roller-shaped rear paper guide member and the reference point is defined as a second line. And then, the when the first line second line corners comprising said first member at an angle to the alpha, fixing device alpha is to satisfy the following expression. −1 <F−24 × π × t × (1−α ÷ 180) ≦ 7 F; total load [Kgf] t; thickness of image support [mm] α; 4. An image supporter between a pair of a heating member and a pressurizing member which presses and abuts each other, and a transfer unit disposed upstream of the pair of members with respect to a feed direction of the image support. A fixing device that is guided and conveyed by a roller-shaped rear paper guide member disposed downstream of the pair of members, wherein a softer member of the pair of members is a first member; A region where the pair of members are in contact with each other on a central cross section of a width is defined as a nip, and a midpoint between a point at an upstream end and a point at a downstream end of the nip in the image support conveying direction is defined as a reference point, A line connecting an end point and the downstream end point as a reference line, a line connecting a downstream end point of the transfer unit and the reference point as a first line, the roller-shaped rear paper guide A line connecting the nip portion of the member and the reference point is defined as a second line, and the first line and the front line The fixing device is characterized in that when the angle formed by the second line and the angle including the first member is α, α satisfies the following expression. −1 <F−24 × π × t × (1−α ÷ 180) ≦ 7 F; total load [Kgf] t; thickness of image support [mm] α; 5. An image supporter between a pair of a heating member and a pressurizing member which presses and abuts each other, and a transfer unit disposed upstream of the pair of members with respect to a feed direction of the image support. A fixing device that is guided and conveyed by a plate-shaped rear paper guide member disposed downstream of the pair of members, wherein a softer member of the pair of members is a first member; A region where the pair of members are in contact with each other on a central cross section of a width is defined as a nip, and a midpoint between a point at an upstream end and a point at a downstream end of the nip in the image support conveying direction is defined as a reference point, A line connecting an end point and the downstream end point as a reference line; a line connecting the downstream end point of the transfer unit and the reference point as a first line; the plate-shaped rear paper guide A line connecting the nip portion of the member and the reference point is defined as a second line, and the first line and the second line A fixing device, characterized in that α satisfies the following expression, where α is an angle formed by the line and includes the first member. −1 <F−24 × π × t × (1−α ÷ 180) ≦ 7 F; total load [Kgf] t; thickness of image support [mm] α; 6. When the image support passes through the nip,
The nip ratio is 1.5 or less, where Nmin is the minimum nip width at the position where the image support passes, Nmax is the maximum nip width, and Nmax / Nmin is the nip ratio. The fixing device described in 1, 2, 3, 4, or 5. 7. An acute angle between a reference line and a first line is β, wherein β is a minus direction when the first member is disposed with respect to the reference line, and β is −40 degrees ≦ β ≦ 7. The method of claim 1, wherein the angle is 0 degrees.
The fixing device as described in the above. 8. An acute angle between a reference line and a second line is γ, wherein γ is a minus direction in which the first member is disposed with respect to the reference line, and γ is −10 degrees ≦ γ ≦ +10
The fixing device according to claim 1, 2, 3, 4, 5, or 6, wherein the temperature is in degrees. 9. The fixing device according to claim 7, wherein the value of α satisfies 130 ≦ α <190 [degrees]. 10. The fixing device according to claim 9, wherein a total load F for pressing and abutting the pair of members is 2 kgf ≦ F <9 kgf.