JP2000305386A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device capable of surely securing a guide path for transfer material with a simple structure. SOLUTION: By fixing a fixing section 13 disposed on one end side of a guide means 10 to a first position 11 of the fixing device, and inserting the leading end of a linear section 14 in a hole 17 disposed on the second position of the fixing device so that the linear section 14 on the guide means is deviated only in the direction crossing the transfer material, even in the case where the guide means 10 is expanded, the linear section is deformed in an arch shape in only the direction regularly crossing the guide means 10. Thus, the guide means, being free from the positional change in the direction of the height, can guide the transfer material in the same state.

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 a copying machine, a printer, and the like, and more particularly, to a fixing device in which unfixed powder toner carried on a transfer material surface is uniformly melted and fixed by hot air. Related to the device.

[0002]

2. Description of the Related Art There is known a fixing device in which a transfer material carrying a heat-soluble powder toner is passed through to thermally fix the toner on the transfer material. For example, a hot-air fixing device that forms a space across a passage that passes through the transfer material and that blows heat from a heater provided inside the transfer material with a blower to fix the transfer material, or a xenon lamp or the like during the passage of the transfer material. 2. Description of the Related Art A flash fixing device that performs fixing using radiant heat is known.

[0003] In particular, taking the above-mentioned hot air fixing device as an example, a fixing device which passes a transfer material carrying a heat-meltable powder toner and thermally fixes the toner on the transfer material,
An upper first and a lower second cover having opposing openings are provided on the toner carrier surface side and the rear side of the transfer material with the transfer material passage therebetween, and a predetermined cover is provided along the transfer material passage in the first cover. A plurality of sheet heaters spaced apart from each other over the width are provided, and these sheet heaters are arranged so as to have a heating surface in a direction intersecting with a surface of the transfer material passing therethrough. Air from the top to the bottom and the hot air generated by the
There is known a fixing device provided with a blowing means for circulating the air inside the cover.

In order to allow the transfer material to pass through the fixing device without being caught between the first cover and the second cover, conventionally, the transfer material is transported to the first cover and the second cover, respectively. The first and second positions, which are the ends in the direction, are bridged by a metal wire or the like so as to be slightly oblique to the transfer direction of the transfer material. The wire is alternately bridged between the first position and the second position, and is fixed with a tension that does not bend.

However, when the fixing device reaches an appropriate fixing temperature at which the transfer material is fixed, the expansion ratio of the wire is generally larger than the expansion ratio of the frame of the fixing device, so that the wire deflects. It hangs down. Particularly, in a fixing device using a large-sized transfer material of A2 size or more, if the wire is fixed with a large tension because the transfer material is wide in the width direction, the fixing device main body is greatly distorted in the vicinity of the central portion, and the uniformity is caused. It is not possible to form a simple space. For this reason, the wire must be fixed to the fixing device with a somewhat weak tension in order to stretch the wire, and the deflection of the wire when the fixing temperature is reached is further increased. In order to prevent this, the strength of the components of the fixing device may be increased, but this increases the cost.

[0006]

In the above-described fixing device, if the wire provided on the first cover is bent, the transfer material carrying the unfixed toner comes into contact with the wire and disturbs the toner image. There is a problem of doing so. Also, if the wire provided on the second cover is bent, the path of the transfer material is changed, and the transfer material is not guided linearly and may cause a paper jam,
The manner in which heat is transmitted is changed, causing problems such as poor fixing.

Furthermore, the transfer material may be guided by bridging the wire from the first position to the second position using a stiff wire member. However, when both ends are fixed, It is not known in which direction the wire member will deform due to expansion when the fixing temperature is reached, and the width of the guide path will not be constant. Further, when the wire member is fixed to only one end side, the direction in which the wire member is bent due to the twisting of the wire member is not stable, so the guide path of the transfer material is not stable, and the transfer material is careless. A paper jam or the like due to contact occurs.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems, and has as its object to provide a fixing device that can reliably secure a guide path for a transfer material with a simple configuration.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a fixing device which passes a transfer material carrying an unfixed toner to melt and fix the toner.
In a fixing device having a plurality of guide units arranged side by side so as to be oblique to the transfer direction of the transfer material from a first position to a second position in the fixing device, the guide unit may include:
An elastically deformable member having a strength not to be deformed by the contact of the transfer material, and a bridging portion for fixing one end to the first position and a bridge between the first position and the second position; And the linear portion is provided so as to be substantially parallel to the transfer direction of the transfer material with no load when the fixed portion is fixed to the fixing device, and The second straight portion is formed so as to bend in a direction crossing the transfer direction of the transfer material.
A hole slightly larger than the thickness of the linear portion is provided at the position, and the straight portion is curved and obliquely provided by inserting the tip of the linear portion into the hole.

Further, the guide means has a substantially U-shape having two linear portions, and the guide means is provided above a surface of a transfer material carrying toner. And the guide means is provided below the surface of the transfer material carrying the toner.

In such a configuration, a fixing portion provided on one end side of the guide means is fixed to the first position of the fixing device,
The guide means may be expanded by inserting the tip of the straight part into a hole provided at the second position of the fixing device so that the straight part of the guide means is deflected only in the direction traversing the transfer material. However, the straight portion always deforms like a bow only in the direction crossing the transfer material. Therefore, there is no change in the position of the guide means in the height direction, and the transfer material can be guided in the same state.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic side sectional view of a fixing device 1 according to the present invention. The fixing device 1 is provided inside the first cover 2, a first cover 2 located on the side of the transfer material that holds the powder toner, a second cover 3 located on the back side of the transfer material. It has a plurality of sheet heaters 5 as heating means spaced apart from each other over a predetermined width along the path 4 of the transfer material, and a cross flow fan 6 as blowing means for blowing air toward the heater surface of the sheet heater 5.

FIG. 2 is a schematic diagram of the first cover 2 of the fixing device as viewed from the direction of arrow A in FIG. 1, and FIG. 3 is a schematic diagram of the second cover 3 of the fixing device as viewed from the direction of arrow B. Show. FIG.
1 to 3, the first cover 2 and the second cover 3
Is formed of a box-like body in which openings 8a and 8b are provided opposite to each other with respect to the transfer material conveying surface with the transfer material passage 4 interposed therebetween, and a space is formed by four walls. Each wall of the first cover 2 and the second cover 3 is provided with an air layer or a heat insulating material layer therebetween in order to prevent heat generated in the first cover 2 from escaping to the outside of the fixing device 1. It has a double structure.
The insides of the first cover 2 and the second cover are preferably plated with black, or are coated with a black heat-resistant paint to ensure good heat retention. Each corner of the first cover 2 is formed in a round shape in order to efficiently circulate hot air in the cover. First cover 2 and second cover
In the openings 8 a and 8 b of the cover 3, heat-resistant guide means 10 for guiding the transfer material toward the discharge roller pair 7 are provided.
Is provided. Reference numeral 11 indicates a first position, and reference numeral 12 indicates a second position.

FIG. 4 shows an example of a preferred shape of the guide means. FIG. 4A shows a front view of the guide means 10 and FIG.
(B) shows a side view of the guide means 10. The guide means 10 has a fixed portion 13 having one end fixed to the first position 11 of the fixing device 1 and a straight portion 14 bridging from the first position 11 to the second position 12. Fixed part 13
Has a shape that can be provided at a position where the transfer material does not enter or abut against the inside of the first cover 2 or the second cover 3. Alternatively, the second cover 3 has a key shape to be fixed to the first position 11 with a screw or the like.
The first position 11 is located at the exit side of the transfer material of the fixing device in the embodiment.

The linear portion 14 is made of a spring material having elasticity, and is provided so as to be substantially parallel to the transfer material transport direction with no load when the fixed portion 13 is fixed at the first position 11. Have been. In addition, the straight line portion 14
Has a longer length than the section between the first position 11 and the second position 12 in order to bridge to the position 12.

FIG. 5 shows another shape of the guide means 10. 5A shows a front view of the guide means 10, FIG. 5B shows a side view of the guide means 10, and FIG.
0 shows a top view. The guide means 10 has a substantially U-shape having two straight portions, and has two straight portions 14.
Are connected to form a fixed portion 13. Fixed part 1
Reference numeral 3 has a shape that can be provided at a position where the transfer material does not enter or abut against the inside of the first cover 2 and the second cover 3. As described above, the straight portion is provided so as to be substantially parallel to the transfer material transport direction with no load when the fixed portion is fixed at the first position of the fixing device.

FIG. 6 is a schematic sectional view showing a state where the guide means 10 is provided on the second cover 3. The transfer material is conveyed from the direction of arrow C, and is provided so as to have a step in the direction sequentially downward so that the transfer material does not hit or catch on a part of the fixing device 1. The fixed portion 13 is fixed at the first position 11, and the leading end of the straight portion 14 is inserted into a hole provided at the second position 12 to bridge. As shown in the drawing, a projection 15 is provided on a part of the fixing device by cutting or raising, and the fixing portion 13 is hooked on the projection 15 so as not to come off, and the holding plate 16 is fixed to the second cover 3 from above. The guide means 10 is fixed to the fixing device main body. Although the description has been given of the second cover 3, the same method is used when the guide means is provided on the first cover.

FIG. 7 is a perspective view of still another guiding means 10. As shown in FIG. The guide means 10 has a fixed portion 13 and a straight line portion 14. In FIG. 7A, the guide means 10 has a substantially U-shaped planar shape, and in FIG. 13 form a substantially triangular shape, and in FIG.
3 is Y-shaped. In the example of FIG. 7, as described above, when the fixing portions 13 are fixed to the first position 11 of the first cover 2 or the second cover 3 of the fixing device, respectively, in the transfer direction of the transfer material under no load. It is formed so as to be substantially parallel with respect to. As a method for fixing the guide means, in addition to the above-described method for fixing the screw or the holding plate 16 or the like, for example, if the guide means 10 shown in FIG. It may be inserted in the hole and fixed.

The second position 12 is slightly larger than the thickness of the linear portion 14 of the guide means 10 at a position where the transfer material does not enter or hit the first cover 2 and the second cover 3. A hole 17 having a shape is provided, and the hole 17 is provided at a position where the straight portion 14 bends in a direction transverse to the transport direction of the transfer material. The tip of the linear portion 14 is inserted into a hole 17 provided at the second position 12 to bend the linear portion 14 so as to be inclined.
In the embodiment, when bridging a cover having a width of 120 mm, the bridging is performed obliquely by providing a hole 17 at a position shifted by about 20 mm in the outer direction.

The position deviated from the fixed position may be such that the linear portion 14 is curved in an arc only in a direction crossing the transfer material. By arranging the linear portion 14 obliquely in this manner, the portion that comes into contact with the conveyed transfer material does not move obliquely and does not contact the same place, and the transfer material does not enter the inside of the cover.

FIG. 8 is a partially enlarged view as seen from the direction of arrow D in FIG. In the guide means 10, the fixed portion 13 is fixed to the fixing device, and the end of the linear portion is inserted into a hole located at a position shifted from the end of the linear portion in a no-load state. This causes the straight portion to bend in the direction of arrow E. The diagonal arrangement of the linear portions is provided so as to extend outward with respect to the transport direction of the transfer material around the center of the transfer material.

In the embodiment, the exit side of the transfer material of the fixing device is set to the first position 11, but if the guide means is provided so that the transfer material is guided without being caught, the second position is used.
The position 12 may be the exit side of the transfer material.

The guide means 10 is preferably made of an elastically deformable member having such a strength as not to be deformed by the contact of the transfer material. In the embodiment, a spring material having a diameter of 1.0 mm is used.

In FIG. 1, reference numeral 18 denotes a rail made of a metal material for pulling out the unitized planar heater unit from the fixing device, and also serves as a shielding member for performing good recirculation in the cover. . The blowing by the blower 6 is gentle, and the air volume is such that the toner does not soar when hot air hits the unfixed powder toner carried on the transfer material.

The sheet heater 5 has a heating surface in a direction intersecting the surface of the passing transfer material, and a plurality of sheet heaters 5 are separated from each other in a direction following the transfer material transport direction. It is provided at an angle. As a result, the hot air impinges obliquely from above along the traveling direction of the transfer material.
The wind bounced off the cover 3 is prevented from winding up from under the transfer material and coming into contact with the guide means provided on the first cover 2.

The planar heater 5 is a belt-shaped heater, and is attached by heat-resistant insulating members 19 (FIG. 2) provided on both sides of the fixing device 1. The planar heater 5 is desirably coated with black plating or black heat-resistant paint.

In the embodiment, as the sheet heater 5, a rolled nichrome wire is preferably used.
A strip-like nichrome wire having a thickness of 5 to 50 mm and a thickness of 0.2 to 0.5 mm is used. The temperature of the sheet heater 5 rises very quickly when energized, and heats the sheet heater 5. By blowing air along the sheet heater 5, the heat of the sheet heater 5 can be efficiently received and converted into hot air.

The sheet heater 5 is formed in a wavy shape, so that the surface area of the sheet heater 5 is made larger than that in a state where the sheet heater 5 is normally stretched. As a result, the amount of heat generated from the planar heater 5 increases, and the size of the apparatus is reduced.

Further, even if a trouble such as a paper jam occurs in the fixing device 1 (or in other places in a copying machine or the like), a stop signal of the transfer material conveying system is detected to supply electricity to the sheet heater 5 and to supply air to the blower. The heat of the sheet heater 5 is rapidly reduced by stopping the driving of the transfer member 6, and the stoppage of the blower 6 prevents hot air from shining on the transfer material, so that the transfer material does not ignite or smoke.

The planar heaters 5 separated from each other are provided with a blower 6
In order to prevent an accident in which adjacent planar heaters 5 come into contact with each other due to the air blow, a heat-resistant insulating guide 20 is provided. The heat-resistant insulating guide 20 has a cutout portion that sandwiches the planar heater 5 and is provided so as to cross the stretched planar heater 5. The heat-resistant insulating guides 20 are preferably made of mica and are provided at predetermined intervals.

The operation of the fixing device 1 having such a configuration will be described. A fixed portion of the guide means is fixed at a first position on each of the first cover and the second cover. At this time, the linear portion is provided so as to be in a direction substantially parallel to the transfer direction of the transfer material with no load. Next, the front end of the linear portion is inserted through a hole provided at a position shifted to the second position. This insertion causes the straight portion to bend like a bow.

In FIG. 1, a transfer material carrying an unfixed powder toner is guided into a fixing device by a known image forming method. The transfer material is guided by the guide means of the second cover 3, is fixed by the blowing of the blowing means, and is discharged to the outside. At this time, the transfer material moves above the linear portion 14 of the guide means. Even when the guide unit is deformed due to thermal expansion, the height position of the guide unit is set by inserting the tip of the linear portion 14 further into the hole 17 or by bending the linear portion only in the direction crossing the transfer material. Maintain a constant position at all times. Even when the guide means provided on the first cover 2 is similarly deformed due to thermal expansion, the end of the linear portion is further inserted into the hole, or the linear portion further curves only in the direction crossing the transfer material. By doing so, the height position of the guide means is always kept constant.

In this way, the circulating air is uniformly blown to each planar heater 5 and has a fixed fixing temperature on the passing transfer material. When the transfer material is conveyed into the fixing device 1, it is uniformly and uniformly spread on the transfer material. The transfer material is conveyed while being pressed against the linear member 10b provided on the second cover 2, and the unfixed powder toner carried on the transfer material is melted. Let it settle.

The transfer material is further conveyed and discharged outside by a discharge roller pair 7. After the transfer material is completely discharged,
By detecting this, the energization of the planar heater 5 may be cut off,
Further, the driving of the blowing means may be stopped. These are to prevent unnecessary heat from leaking from the fixing device to other sections in the copying machine, for example, an image forming section such as the photosensitive drum 2 as much as possible.

Although the fixed portion of the guide means is provided on the exit side of the fixing device, it may be provided on the entrance side. At this time, it is necessary to prevent the transfer material from hitting the leading end of the transfer material. In the above description, the guide means is provided on the first cover and the second cover, but may be provided on either one of them.

[0036]

As described above, the fixing device of the present invention is a first fixing device in the fixing device.
A plurality of guide means having a linear portion and a fixed portion are arranged side by side so as to be inclined with respect to the transfer direction of the transfer material from the position to the second position, and a hole of the fixing device provided at a position shifted from the linear portion Even if the linear part of the guide means is deformed due to expansion, it is further curved in a certain direction or further inserted into the hole, so that the height can be kept constant and the transfer material can be securely inserted. I can guide you. Also, the transfer material is provided symmetrically so as to be oblique from the vicinity of the center toward the outer direction, but since it is oblique due to the curvature of the linear portion, it is possible to use guide means of the same shape, Can be shared.

[Brief description of the drawings]

FIG. 1 is a schematic sectional side view showing a fixing device according to the present invention.

FIG. 2 is a schematic top view showing the first cover viewed from the direction of arrow A in FIG. 1;

FIG. 3 is a schematic top view showing the second cover as viewed from the direction of arrow B in FIG. 1;

FIG. 4A is a side view showing a guide unit. (B) Front view showing guide means.

FIG. 5A is a side view showing another guide means. (B) Front view showing another guide means. (C) A top view showing another guide means.

FIG. 6 is a schematic side view showing a state where a guide unit is attached to a fixing device.

FIG. 7A is a schematic perspective view showing still another guide means. (B) The schematic perspective view which shows another guide means. (C) The schematic perspective view which shows another guide means.

FIG. 8 is a partially enlarged top view of the second cover when the guide unit of FIG. 6 is viewed from the direction of arrow D.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixing apparatus 2 1st cover 3 2nd cover 4 Passage 5 Planar heater 6 Cross flow fan 7 Discharge roller pair 8a, 8b Opening 9 Discharge roller 10 Guide means 11 1st position 12 2nd position 13 Fixed part 14 Linear part 15 Protrusion 16 Hold down plate 17 Hole 18 Rail 19 Heat resistant insulation member 20 Heat resistant insulation guide

Claims (4)

[Claims] 1. A fixing device for dissolving and fixing a toner by passing a transfer material carrying an unfixed toner, comprising:
In a fixing device having a plurality of guide units arranged side by side so as to be oblique to the transfer direction of the transfer material from a first position to a second position in the fixing device, the guide unit may include:
An elastically deformable member having a strength not to be deformed by the contact of the transfer material, and a bridging portion for fixing one end to the first position and a bridge between the first position and the second position; And the linear portion is provided so as to be substantially parallel to the transfer direction of the transfer material with no load when the fixed portion is fixed to the fixing device, and The second straight portion is formed so as to bend in a direction crossing the transfer direction of the transfer material.
A hole slightly larger than the thickness of the linear portion is provided at the position, and the tip of the linear portion is inserted into the hole so as to bend the linear portion so as to be inclined. 2. The fixing device according to claim 1, wherein the guide unit has a substantially U-shape having two linear portions. 3. The image forming apparatus according to claim 1, wherein said guide means is provided above a surface of a transfer material carrying toner.
Or the fixing device according to any one of 2. 4. The image forming apparatus according to claim 1, wherein said guide means is provided below a surface of the transfer material carrying the toner.
Or the fixing device according to any one of 2.