JP2002341684A - Fixing unit of image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the temperature rise of a resin cap with a simple configuration in a fixing unit of an image forming apparatus which thermally fixes a toner image transferred to a recording sheet and which is miniaturized by disposing a power feeding member with which a heater terminal is connected and the resin cap for supporting the power feeding member in the vicinity of the outer end of the heating roll. SOLUTION: The fixing unit of the image forming apparatus is provided with: a heating rotating member Fh and a pressurizing rotating member Fp; resin caps 1 and 2 placed on the outside of the outer end ion the axial direction of the heating rotating member Fh; electrically conductive metallic power feeding members 3, 6, and 7 connected to the power source for heater driving; heat generating parts h1a, h2a; and metallic lead wires h1b, h1d, h2b, and h2d. The fixing unit of the image forming apparatus is further provided with: heaters h1 and h2 having the lead wires h1b, h1d, h2b and h2d whose outer ends are connected to the power feeding members 3, 6, and 7; and thermal shield boards 5 and 11 placed between the outer end of the heating rotating member Fh and the resin caps 1 and 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an unfixed toner image on a recording sheet, wherein the recording sheet on which the toner image has been formed passes through a fixing area which is a contact area between a pair of fixing rotating members. And a fixing device for an image forming apparatus for heating and fixing a toner image on a recording sheet. The fixing device of the image forming apparatus of the present invention is used in an image forming apparatus such as an electrophotographic copying machine, a facsimile (FAX), and a printer.

[0002]

2. Description of the Related Art As a fixing device of the image forming apparatus, a fixing device described in the following publication (J01) is conventionally known. In this publication, a heat insulating cap or a shielding plate is arranged outside the both ends of the heating roll and inside the foils at both ends of the heater, and the heating degree of the foil at both ends of the heater is described. To prevent oxidation of the foil part and extend the life of the heater itself, and at the same time, use less expensive heat-resistant lead wires for the heater. There is described a fixing device which improves the image quality. However, there is a problem that it is difficult to reduce the size of the fixing device in which such a foil portion is arranged outside the heating roll.

[0003]

With the miniaturization of the image forming apparatus and its fixing device, a configuration is adopted in which a metal heater terminal is used and the metal terminal is connected to a power supply member fixed to a resin cap. It has become so. When such a configuration is adopted, since the resin cap and the heater are close to each other, there is a concern that the temperature of the resin cap may increase due to radiant heat of the heater.

[0004] In view of the above circumstances, the present invention has the following description (O01) as a technical subject. (O01) In the fixing device miniaturized by disposing the power supply member to which the heater terminal is connected and the resin cap supporting the power supply member close to the outer end of the heating roll, the temperature of the resin cap can be easily increased. To prevent it.

[0005]

Next, the present invention devised to solve the above-mentioned problems will be described. Elements of the present invention are used to facilitate correspondence with elements of the embodiments described later. , The reference numerals of the elements of the embodiment are enclosed in parentheses. The reason why the present invention is described in correspondence with the reference numerals of the embodiments described below is to facilitate understanding of the present invention and not to limit the scope of the present invention to the embodiments.

(1st invention) In order to solve the aforementioned problem,
The fixing device (F) of the image forming apparatus according to the present invention includes the following constituent features (A01) to (A05). (A01) A heating rotating member (F
h) and the heating rotating member (Fh) and the pressing rotating member (Fp) for fixing an unfixed toner image on a recording sheet passing through a fixing area (Q5) formed by the pressure contact area of the pressing rotating member (Fp). ), (A02) the heating rotary member (F
h) Resin caps (1, 2) arranged outside the outer end in the axial direction, (A03) A conductive metal support supported by the resin caps (1, 2) and connected to a heater driving power supply. Power supply members (3, 6, 7), (A04) heater heaters (h1a, h2a) and heater heaters (h1) disposed in the heating rotating member (Fh) so as to extend in the rotation axis direction.
a, h2a) and a metal lead wire (h1b, h1d, h2b, h2d) connected to the outer end of the lead wire (h1b, h1d, h2b, h2d). The heater (h) connected to the members (3, 6, 7)
(1, h2), (A05) A heat shielding plate (5, 11) disposed between the outer end of the heating rotary member (Fh) and the resin cap (1, 2).

(Operation of the First Invention) In the fixing device (F) of the image forming apparatus of the present invention having the above-described configuration, the heating rotating member (Fh) and the pressing rotating member (Fp) rotate while being pressed against each other. I do. A fixing region (Q5) is formed by the pressure contact region of the heating rotating member (Fh) and the pressing rotating member (Fp), and the heating rotating member (Fh) and the pressing rotating member (Fp) are fixed to the fixing region (Q5). To fix the unfixed toner image on the recording sheet passing therethrough. Heater (h1, h
2) a heater heating section (h1a, h2a) that is disposed inside the heating rotary member (Fh) so as to extend in the direction of the rotation axis.
And metal lead wires (h1b, h1d, h2b,...) Connected to outer ends of the heater heating portions (h1a, h2a).
h2d). The lead wires (h1b, h1d,
h2b, h2d) are connected at their outer ends to power supply members (3, 6, 7) made of conductive metal. The lead wire (h
1b, h1d, h2b, h2d) are directly connected to the power supply members (3, 6, 7) by welding, welding, or the like, or the lead wires (h1b, h1d, h2b, h2).
d) the heater terminals (h1c, h1e,
h2c, h2e). The power supply members (3, 6, 7) are supported by the resin caps (1, 2) and connected to a heater driving power supply. The resin cap (1, 2) is disposed outside the axially outer end of the heating rotary member (Fh). Since the heat shielding plates (5, 11) are disposed between the outer end of the heating rotation member (Fh) and the resin caps (1, 2), the heating rotation by the heaters (h1, h2) is performed. Heat applied to the resin cap (1, 2) from the outer end of the member (Fh) is shielded by the heat shield plates (5, 11). Therefore, it is possible to prevent the resin cap (1, 2) from being heated or damaged due to the temperature rise.

[0008]

(Embodiment 1) A fixing device (F) of an image forming apparatus according to Embodiment 1 of the present invention is characterized by having the following constitutional requirement (A06) in the present invention. . (A06) The power supply member (3, 6, 7) integrally formed with the heat shield plate (5, 11).

(Operation of the First Embodiment) The fixing device (F) of the image forming apparatus according to the first embodiment of the present invention having the above-described configuration.
Since the power supply members (3, 6, 7) are integrally formed with the heat shielding plates (5, 11), the number of components can be reduced.

(Second Embodiment) A fixing device (F) of an image forming apparatus according to a second embodiment of the present invention has the following constituent features (A07) and (A08) in the first embodiment of the present invention. It is characterized by the following. (A07) Movement of the heat-insulating collar (SP) for preventing a rise in temperature of the resin-made rotational force transmission gear (G1) or the bearing mounted on the outer end of the heating rotary member (Fh) to the axially outer end. Metal ring-shaped retaining ring (R) attached to the outer end of the heating rotary member (Fh) to regulate
08) A metal ring-shaped plate (P) arranged radially inside the retaining ring (R) in the axial direction of the heating rotating member (Fh) and having a larger radial width than the retaining ring (R).
L).

(Operation of the Second Embodiment) The fixing device (F) of the image forming apparatus according to the second embodiment of the present invention having the above configuration.
Then, a heat-insulating collar (SP) for preventing a rise in the temperature of the resin-made rotational force transmission gear (G1) or the bearing is attached to the outer end of the heating rotary member (Fh). A metal ring-shaped retaining ring (R) is attached to the outer end of the heating rotary member (Fh), and is connected to the axially outer end of the rotational force transmission gear (G1) or the heat insulating collar (SP). Restrict movement. When the heaters (h1, h2) generate heat, the torque transmitting gear (G
1) Alternatively, the heat insulating collar (SP) thermally expands to move its outer end face to the axial outer end side, or the metal ring plate (PL) due to the axial thrust force of the heating rotator.
May be pressed. In that case, since the ring-shaped plate (PL) has a larger width in the radial direction than the retaining ring (R), the outer end surface is regulated by a wider contact area than when regulated only by the stopper (R). . For this reason, the pressure (force per unit area) received from the ring-shaped plate (PL) by the outer end face of the rotational force transmission gear (G1) or the heat insulating collar (SP) during the thermal expansion becomes smaller, and the Deformation can be prevented.

Embodiment 1 Next, a specific example (embodiment) of an embodiment of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiment. In addition,
In order to facilitate understanding of the following description, in the drawings,
The front-rear direction is the X-axis direction, the left-right direction is the Y-axis direction, the up-down direction is the Z-axis direction, and the directions or sides indicated by arrows X, -X, Y, -Y, Z, -Z are forward, rearward, and rearward, respectively. Right, left, upper, lower, or front, rear, right, left, upper, lower. Also, in the figure, those in which “•” is described in “○” mean an arrow pointing from the back of the paper to the front,
A mark with "x" in "o" means an arrow pointing from the front to the back of the paper.

FIG. 1 is an explanatory view of a color image forming apparatus provided with a fixing device according to a first embodiment of the present invention. In FIG.
The image forming apparatus U includes an automatic document feeder U1 and an image forming apparatus main body (copier) U2 having a platen glass PG for supporting the same. The automatic document feeder U1
Is transported from a document feed tray TG1 on which a plurality of documents Gi to be copied are placed in a stack, and from a document feed tray TG1 through a copy position (document reading position) on the platen glass PG. And a document discharge tray TG2 from which the document Gi is discharged.

The image forming apparatus main body U2 has a UI (user interface) through which a user inputs an operation command signal such as a copy start signal, an exposure optical system A, and the like.
Reflected light from a document conveyed on the platen glass PG by the automatic document feeder U1 or a document (not shown) manually placed on the platen glass PG is transmitted through the exposure optical system A to the CCD (CCD). R (red), G
(Green) and B (blue). An IPS (image processing system) converts the RGB electrical signals into Y (yellow), M (magenta), C (cyan), and K (black) image data and temporarily stores the image data. Output to the laser drive circuit DL at a predetermined timing.

The surface of the image carrier (photosensitive drum) PR which rotates in the direction of the arrow Ya is uniformly charged by the charging roll CR, and the latent image writing position Q1, the developing area Q2, and the developing area Q1
The sheet sequentially passes through the next transfer area Q3. The laser drive circuit D
An ROS (latent image writing device) driven by L exposes and scans the surface of the image carrier PR at the latent image writing position Q1 with the laser beam L to form an electrostatic latent image on the surface of the image carrier PR. . To form a full-color image, four colors of Y (yellow), M (magenta), C (cyan), and K (black) are used.
An electrostatic latent image corresponding to a color image is sequentially formed. In the case of a monochrome image, only an electrostatic latent image corresponding to a K (black) image is formed.

The rotary type developing device G rotates in the developing area Q2 sequentially with the rotation of the rotating shaft Ga.
(Yellow), M (magenta), C (cyan), K
It has developing units GY, GM, GC, and GK for four colors (black). Each of the developing units GY, GM, GC, and GK has a developing roll GR for transporting a developer to the developing area Q2, and forms an electrostatic latent image on the image carrier PR passing through the developing area Q2. Develop into a toner image Tn.

Below the image carrier PR, a slide frame F1 is provided by a pair of left and right slide rails SR, SR.
(Indicated by a two-dot chain line) is slidably supported in the front-rear direction (X-axis direction). A belt frame F2 of the belt module BM is supported on the slide frame F1 so as to be rotatable up and down around a hinge axis F2a. The belt module BM includes a plurality of belt support rolls (Rd, Rd) that rotatably support the intermediate transfer belt B.
t, Rf, T2a), a primary transfer roll T1, a contact roll T2c, and the belt frame F2 that supports them. The plurality of belt support rolls (Rd, Rt, Rf, T2a) are
d, a tension roll Rt, an idler roll (free roll) Rf, and a backup roll T2a, and the backup roll T2a includes the contact roll T2c.
Is in contact.

The belt module BM is rotatable up and down around the hinge axis F2a. When the belt module BM is rotated downward, the belt module BM does not come into frictional contact with the image carrier PR together with the slide frame F1 to form an image. Device body U
2 can go in and out. The primary transfer roll T1
Is applied with a primary transfer voltage having a polarity opposite to the charge polarity of the toner by the power supply circuit E controlled by the controller C, and transfers the toner image Tn on the surface of the image carrier PR to the intermediate transfer belt B in the primary transfer area Q3. First transfer. In the case of a full-color image, Y, M, and Y are sequentially formed on the surface of the image carrier PR.
The toner images Tn of the respective colors C and K are transferred to the primary transfer area Q3.
In step (1), primary transfer is sequentially performed on the surface of the intermediate transfer belt B so that a full-color multiple toner image is finally formed on the intermediate transfer belt B. When a monochromatic monocolor image is formed, only one developing unit is used, and the monochromatic toner image is primarily transferred onto the intermediate transfer belt B. After the primary transfer, the residual toner on the surface of the image carrier PR is removed by the image carrier cleaner CLp.
And the charge is eliminated by the charge eliminating roll JR.

Below the backup roll T2a, a secondary transfer slide frame Fs slidable in the front-rear direction (X-axis direction) by a pair of left and right slide rails SR, SR is moved forward and backward with respect to the image forming apparatus main body U2. It is detachably supported in the direction. A secondary transfer lifting frame Ft of the secondary transfer unit Ut is supported on the secondary transfer slide frame Fs so as to be rotatable up and down around a hinge axis Fta. When the secondary transfer unit Ut is rotated downward, the secondary transfer unit Ut can enter and exit the image forming apparatus main body U2 without making frictional contact with the belt module BM. The secondary transfer unit Ut includes a secondary transfer roll T2b,
Next transfer roll cleaner CLt and roll support lever Lr
, Sheet guide SG2 after transfer, and sheet conveying belt B
H and the secondary transfer lifting frame Ft supporting them.
And

The roll support lever Lr is a lever for supporting the secondary transfer roll T2b and the secondary transfer roll cleaner CLt. The roll support lever Lr is rotated around a hinge axis La by a motor (not shown) to rotate the secondary transfer roll T2b. The intermediate transfer belt B is moved between a secondary transfer position in contact with the intermediate transfer belt B and a standby position separated from the intermediate transfer belt B. A secondary transfer area Q4 is formed by the contact area between the secondary transfer roll T2b and the intermediate transfer belt B, and a secondary transfer unit T2 is formed by the secondary transfer roll T2b, the backup roll T2a, and the contact roll T2c. I have.

The recording sheets S stored in the sheet feeding tray TR1 are taken out by a pickup roll Rp at a predetermined timing, separated one by one by a separating roll Rs, and conveyed to a registration roll Rr. The cashier roll Rr
The recording sheet S conveyed to the pre-transfer sheet guide S is synchronized with the timing at which the primary-transferred multi-toner image or single-color toner image moves to the secondary transfer area Q4.
The sheet is conveyed from G1 to the secondary transfer area Q4. When the recording sheet S passes through the secondary transfer area Q4, a secondary transfer voltage having the same polarity as the toner charging polarity is applied to the contact roll T2c of the secondary transfer unit T2 from the power supply circuit E controlled by the controller C. Is done. The secondary transfer unit T2 collectively transfers the color toner image primarily transferred onto the intermediate transfer belt B onto the recording sheet S in the secondary transfer area Q4.
Next transfer. The residual toner is removed from the intermediate transfer belt B after the secondary transfer by the belt cleaner CLb. Further, the secondary transfer roll T2b is a secondary transfer roll cleaner CLt.
As a result, the toner attached to the surface is collected.

Incidentally, the secondary transfer roll T2b and the belt cleaner CLb are arranged so as to be able to be separated (separated and contacted) from the intermediate transfer belt B, and when a color image is formed, the final color is not fixed. Until the toner image is primarily transferred to the intermediate transfer belt B, the toner image is separated from the intermediate transfer belt B. The secondary transfer roll cleaner CLt
Is the secondary transfer roll T2 with respect to the intermediate transfer belt B.
Move away from and move with b. The recording sheet S on which the toner image has been secondarily transferred is conveyed to a fixing area Q5 by a post-transfer sheet guide SG2 and a sheet conveying belt BH. When the recording sheet S passes through the fixing area Q5, a heating roll (heating rotating member) F
h and a fixing device F having a pair of fixing rolls (Fh + Fp) composed of pressure rolls (pressure rotating members) Fp. The recording sheet S on which the toner image has been fixed is discharged to the recording sheet discharge tray TR2.
The sheet transporting device SH is constituted by the elements indicated by the reference numerals Rp, Rs, Rr, SG1, SG2, and BH.

(Fixing Device) FIG. 2 is an enlarged view of the fixing device of the first embodiment shown in FIG. FIG. 3 is a sectional view taken along the line III-I of FIG.
FIG. 2 is a sectional view taken along line II. FIG. 4 is a sectional view taken along the line IV-IV of FIG. 2 to 4, the heating roll Fh of the fixing device F has a heater h1 for a small-size sheet and a heater h2 for a large-size sheet built therein, and both ends in the roll axis direction are provided with bearings Fha, Fha. It is rotatably supported by the front and rear frames Ff and Fr. Further, both ends in the roll axis direction of the pressure roll Fp are rotatably supported by front and rear frames Ff and Fr via bearings Fpa and Fpa.

At the rear end of the heating roll Fh, on the rear side of the bearing Fha, a gear G1 made of heat-resistant resin for transmitting rotational force is mounted with a heat insulating spacer (heat insulating collar) SP interposed therebetween. . A metal ring-shaped plate PL and a retaining ring R are mounted on the rear side of the resin gear G1. The radial width of the ring-shaped plate is set larger than the radial width of the retaining ring R, and the contact area of the ring-shaped plate PL with the rear side surface of the gear G1 is the retaining ring R
Is formed so as to be larger than a contact area in the case of contacting the rear side surface of the gear G1.

At the front end of the heating roll Fh, a heat insulating spacer SP is mounted in front of the bearing Fha.
A metal ring-shaped plate PL and a retaining ring R are mounted on the front side of the heat insulating spacer SP. The radial width of the ring-shaped plate is set to be larger than the radial width of the retaining ring R, and the contact area of the ring-shaped plate PL with the front surface is such that the retaining ring R is located on the front surface of the heat insulating spacer SP. It is formed so as to be larger than the contact area in the case of contact.

In FIG. 4, the small-size sheet heater h1 is a heater for fixing A4 SEF (A4 short edge feed, that is, a conveyance sheet whose front and rear ends in the conveyance direction are short edges of A4 size sheets). , The length of which is the length of the short edge of the A4 sheet. The small-size sheet heater h1 is a small-size sheet (the sheet width in the direction perpendicular to the sheet conveyance direction is A4SE).
F has a width the same as that of the small-size sheet fixing area R1 (see FIG. 4), which is an area through which the sheet F passes. Heater h1 for small size sheet is A4SEF and B5SE
When fixing the sheet F, the small-size sheet fixing area R
On / off control is performed to maintain the temperature of No. 1 at the fixing temperature.

The large-size sheet heater h2 is A4L.
EF (A4 long edge feed, that is, a heater used when fixing a transport sheet whose front and rear ends in the transport direction are long edges of an A4 size sheet), the length of which is the length of the long edge of the A4 sheet Same as length. The large-size sheet heater h2 is a large-size sheet (the sheet width in the direction perpendicular to the sheet conveyance direction is A4SEF).
It has the same width as the large-size sheet fixing area R2 (see FIG. 4), which is an area through which a longer sheet passes. A4LEF, A3SEF as the large size sheet
(A3 short edge feed), B4SEF, B5L
There are EF sheets etc. When fixing these sheets,
The fixing is performed using the large-size sheet heater h2. In FIG. 4, the large-size sheet heater h2 is turned on and off to maintain the temperature of the large-size sheet fixing region R2 at the fixing temperature. In FIG. 4, a difference fixing area R3 (= R2-R1), which is a difference area between the large-size sheet fixing area R2 and the small-size sheet fixing area R1, is heated only at the time of fixing the large-size sheet. Is an area that is not heated during fixing.

The small-size sheet heater h1 has a heater heating section h1a, a front heater terminal h1c connected to a front end thereof via a lead wire h1b, and a rear end section of the heater heating section h1a via a lead wire h1d. It has a rear heater terminal h1e connected thereto, and a glass h1f for sealing the heater heating section h1a and a part of the lead wires h1b and h1d before and after the heater heating section h1a. The front and rear heater terminals h1c and h1e protrude outward from the outer end of the heating roll Fh (heating rotating member). Similarly to the small-size sheet heater h1, the large-size sheet heater h2 has a heater heat generating portion h2a and front and rear lead wires h.
2b and h2d and heater terminals h2c and h2e
And sealing glass h2f.

FIG. 5 is an explanatory view of a front end portion of the heating roll, FIG. 5A is a perspective view, and FIG. 5B is a view showing a part of FIG. 3 to 5, front and rear resin caps 1 and 2 are arranged adjacent to and opposed to the front and rear ends of the heating roll Fh, respectively. The front resin cap 1 has a horizontal step portion 1a, and upper and lower upper vertical portions 1b and lower vertical portions 1c. The rear resin cap 2, like the front resin cap 1, has a horizontal step portion 2a, an upper vertical portion 2b, and a lower vertical portion 2c. The front horizontal step portion 1a
, A power supply plate for ground connection (ground-side power supply member) 3 is fixed, and the heater terminals h1c and h2c are fixed to the power supply plate 3 for ground connection with screws. The power supply plate 3 for ground connection is grounded by a ground wire 4. A heat shield plate 5 is fixed to the lower vertical portion 1c of the front resin cap 1 by a screw penetrating a cylindrical spacer having a screw through hole (not shown), and the lower vertical portion 1c, the heat shield plate 5, Between them, a gap is formed at a sufficient interval for shielding heat by the spacer (not shown). Therefore, the heat shielding plate 5 prevents the radiation heat of the heaters h1 and h2 from being applied to the front resin cap 1.

Power supply plates (power supply side power supply plates) 6, 7 for power supply connection are fixed to the rear horizontal step portion 2a, and the power supply plate 6 is a small-size sheet heater h.
The power supply plate 1 is a plate for supplying power, and is connected to a power supply circuit (not shown) via a power supply lead wire 8. Also,
The power supply plate 7 is a plate for supplying power to the large-size sheet heater h2, and is connected to a power supply circuit (not shown) via a power supply lead wire 9. As in the case of the front resin cap 1, the heat shield plate 11 is fixed to the lower vertical portion 2c of the rear resin cap 2 by screws (not shown) penetrating a cylindrical spacer (not shown). A gap is formed between the lower vertical portion 2c and the heat shield plate 11 at a sufficient interval to shield heat. Therefore, the heat shielding plate 11 prevents the radiant heat of the heaters h1 and h2 from being applied to the rear resin cap 2.

(Effect of Embodiment 1) The fixing device of the image forming apparatus of Embodiment 1 includes a heat shielding plate 5 between the end of the heating roll Fh and the resin caps 1 and 2 disposed outside the end.
Since the radiant heat radiated from the heater h1 or h2 of the heating roll Fh is shielded by the heat shield plates 5 and 11, the radiant heat can be prevented from entering the resin caps 1 and 2. Therefore, deformation or damage of the resin caps 1 and 2 due to heat can be prevented.

The radial width of the ring-shaped plate PL mounted between the outer surface (rear surface) of the resin gear G1 and the retaining ring R is greater than the radial width of the retaining ring R. The gear G of the ring-shaped plate PL is set to be large.
The contact area on the rear side of the gear 1 is formed to be larger than the contact area when the retaining ring R contacts the rear side of the gear G1. For this reason, the gear G1 made of resin is moved by the thermal expansion of the heat insulating spacer SP to the ring-shaped plate PL.
When the gear G1 is pressed, the contact pressure (the pressing force per unit area) of the ring-shaped plate PL acting on the gear G1 is smaller than when the gear G1 is pressed directly against the retaining ring R. Therefore, even if the resin gear whose temperature has risen is pressed by the ring-shaped plate PL, the contact pressure is small, so that the deformation of the resin gear G1 can be prevented.

A heat insulating spacer SP and a retaining ring R mounted on the front side of the bearing Fha on the front end side of the heating roll Fh.
The contact area between the ring-shaped plate PL and the front side surface of the heat-insulating spacer SP is larger than the contact area when the retaining ring R contacts the front surface of the heat-insulating spacer SP. Have been. For this reason, when the heat insulating spacer SP is pressed against the ring-shaped plate PL due to thermal expansion, compared with the case where the heat insulating spacer SP is directly pressed against the retaining ring R, the ring-shaped plate PL acting on the heat insulating spacer SP is reduced. Contact pressure (pressing force per unit area)
Becomes smaller. Therefore, even if the heat insulating spacer SP whose temperature has increased is pressed against the ring-shaped plate PL, the contact pressure is small, so that the deformation of the heat insulating spacer SP can be prevented.

The deformation of the gear G1 and the heat insulating spacer SP is prevented by the ring-shaped plate PL.
The ring-shaped plate PL, the heat insulating spacer SP, and the gear G
1. The generation of an axial gap between the members of the retaining ring R is prevented. Therefore, the heating roll Fh is prevented from moving in the axial direction, and damage to the fixing device F due to contact between the end faces of the heaters h1 and h2 and the heat shielding plates 5 and 11 due to the movement of the heating roll Fh is also prevented. Is prevented.

(Embodiment 2) FIG. 6 is an explanatory view of a main part of a fixing device of an image forming apparatus according to Embodiment 2 of the present invention. FIG. 6A is an enlarged sectional view of a front end portion of a heating roll, and FIG. It is an expanded sectional view of a rear end part. FIG. 7 is a perspective view of the front end of the second embodiment. In the description of the second embodiment, components corresponding to the components of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. Example 2
Is different from the first embodiment in the following points, but is configured similarly to the first embodiment in other points. 6 and 7
In the second embodiment, the power supply plate 3 for ground connection of the second embodiment
A power supply plate portion 3a fixed on the front horizontal step portion 1a of the resin cap 1, a heat shielding portion 3b arranged with a gap along a rear surface of the lower vertical portion 1c,
A heat shielding portion 3c disposed opposite to a central portion of the upper vertical portion 1b in the left-right direction, and a power supply plate portion 3a;
The heat shield 3b and the heat shield 3c are integrally formed.

The heater terminals h1c, h2 at the outer ends of the leads h1b, h2b are connected to the power supply plate 3a for ground connection.
c is fixed, and the heat shielding portion 3b is
Radiation heat from a, h2a is prevented from entering the lower vertical portion 1c. Therefore, in the second embodiment, the heat shield plate 5 of the first embodiment is omitted, and the power supply plate portion 3a and the heat shield portions 3b and 3c having the function of the heat shield plate 5 of the first embodiment are integrated. A formed power supply plate (heat shield plate and power supply plate) 3 is provided.

The power supply plate 6 for supplying voltage to the small-size sheet heater h1 has a power supply plate portion 6a and heat shielding portions 6b and 6c, like the power supply plate 3 for ground connection. The power supply plate 6a and the heat shields 6b, 6c are integrally formed. Power supply plate 7 for supplying power to large-size sheet heater h2
Like the power supply plate 6, the power supply plate 6 has a power supply plate portion 7a and heat shield portions 7b and 7c, and the power supply plate portion 7a and the heat shield portions 7b and 7c are integrally formed. Therefore, in the second embodiment, the heat shield plate 11 of the first embodiment is omitted, and the power supply plates 6 and 7 in which the power supply plate portions 6a and 7a and the heat shield portions 6b, 7b, 6c and 7c are integrally formed are provided. ing.

In the second embodiment, the heat shield 3c disposed between the upper vertical portion 1b and the front end of the heating roll Fh is provided only at the center in the left-right direction. Since the distance from the front end of the heating roll Fh is farther than the lower vertical portion 1c, the upper vertical portion 1b is deformed by radiant heat from the heater heat generating portions h1a and h2a,
It will not be damaged. Similarly, the heat shielding portions 6c, 7
c is also provided only at the center in the left-right direction (not shown), but the upper vertical portion 2b is farther from the rear end of the heating roll Fh than the lower vertical portion 2c. The portion 2b is not deformed or damaged by radiant heat from the heater heat generating portions h1a, h2a. The power supply plates 3, 6, and 7 of the second embodiment include heat shielding portions 3 b and 6.
Since b, 7b, 3c, 6b, and 7b are integrally formed, the number of parts can be reduced as compared with the first embodiment.

(Modifications) Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above-described embodiments, but includes the gist of the present invention described in the claims. Various changes can be made within the scope. Modified embodiments of the present invention will be exemplified below. (H01) The present invention can be applied to an image forming apparatus other than a copying machine, such as a printer and a facsimile. (H02) In each of the above embodiments, instead of forming a gap between the heat shielding portion and the resin cap, the heat radiated from the heater is shielded by using a heat insulating adhesive or a plate-shaped heat insulating spacer. It is also possible.

[0040]

The image forming apparatus according to the present invention has the following effect (E01). (E01) In the fixing device miniaturized by disposing the power supply member to which the heater terminal is connected and the resin cap supporting the power supply member close to the outer end of the heating roll, the temperature rise of the resin cap is simplified. Can be prevented.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a color image forming apparatus including a fixing device according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of the fixing device of the first embodiment shown in FIG.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a sectional view taken along line IV-IV of FIG.

5 is an explanatory view of a front end side portion of the heating roll, FIG. 5A is a perspective view, and FIG. 5B is a view showing a part of FIG. 5A by a virtual line.

FIG. 6 is an explanatory view of a main part of a fixing device of an image forming apparatus according to a second embodiment of the present invention. FIG. 6A is an enlarged sectional view of a front end of a heating roll, and FIG. It is an expanded sectional view.

FIG. 7 is a perspective view of a front end portion of the second embodiment.

[Explanation of symbols]

F: fixing device, Fh: heating rotary member, Fp ...
・ Pressurized rotation member, G1 ... Rotation force transmission gear, h1, h
2 ... heater, h1a, h2a ... heater heating section,
h1c, h2c: heater terminal, PL: ring-shaped plate, Q5: fixing area, R: retaining ring, SP
... Insulation collar, 1,2 ... Resin cap, 5,1
1 ... heat shield plate, 6, 7 ... power supply member.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Yoshiaki Hiranaka 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Kenji Hara 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. F-term (Reference) 2H033 AA21 AA23 BA03 BA05 BA26 BB18 BB21 BB22 BB36 BB37 3J103 AA02 AA41 AA74 BA05 CA52 CA78 FA01 GA02 GA57 GA58 GA60 3K058 AA12 BA18 CE17 CE21 DA02 DA11 GA06

Claims (3)

[Claims] 1. A fixing device of an image forming apparatus having the following constitutional requirements (A01) to (A05): (A01) a fixing member formed by a heating rotary member rotating while pressing against each other and a pressure contact region of a pressing rotary member. The heating rotary member and the pressing rotary member for fixing the unfixed toner image on the recording sheet passing through the fixing area; (A02) a resin cap disposed outside the axial outer end of the heating rotary member; A) a power supply member made of a conductive metal supported by the resin cap and connected to a power supply for driving the heater; (A04) a heater heat generating portion disposed inside the heating rotating member so as to extend in a rotation axis direction; A heater having a metal lead wire connected to an outer end portion of the heater, the outer end portion of the lead wire being connected to the power supply member; and (A05) an outer end portion of the heating rotary member and the resin. Placed between cap Heat shielding plates. 2. The method according to claim 1, wherein the following component requirements (A06) are provided.
(A06) The power supply member integrally formed with the shielding plate. 3. The fixing device for an image forming apparatus according to claim 1, wherein the fixing device has the following constitutional requirements (A07) and (A08).
(A07) The heating rotary member for restricting the axial movement of the heat-insulating collar for preventing the temperature rise of the resin-made rotational force transmission gear or bearing mounted on the outer end of the heating rotary member. (A08) A metal ring-shaped retaining ring attached to the outer end portion of (A08) a metal that has a greater radial width than the retaining ring and is disposed inside the retaining ring in the axial direction of the heating rotating member. Ring plate.