JP2002148973A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus with a fixing device using radiation heat to enable stable feed of a transfer material and uniform fixation of a toner image to prevent overheat of the transfer material due to faulty feed of the transfer material. SOLUTION: An interval between a feeding member 104a consisting of endless wire and an auxiliary feeding member 104b is set to be narrower at a discharge port than that of an inlet region of the transfer material. The transfer material 106 is fed by driving the feeding member 104a and the auxiliary feeding member 104b by rotating feeding pulleys 110a, 110b by a rotationally driving source which is not shown in a figure, an unfixed toner image 107 is melted by the radiation heat and the transfer material 106 is fed to a guide member 108 at the inlet of a calender roller 105. The auxiliary feeding member 104b prevents intrusion of the transfer material 106 in the direction of a far infrared heating part 101, suppresses a curl on the tip of the transfer material 106 and performs the stable feed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile and the like equipped with a fixing device for making a toner image permanent on a transfer material surface using radiant heat.

[0002]

2. Description of the Related Art Heretofore, in a fixing device in an image forming apparatus such as a copying machine, a printer, a facsimile, etc., a heating method using a halogen heater as a heat source has been independently adopted. This fixing device has a fixing roller in which a halogen heater is arranged on at least one of a pair of rollers. While rotating the heated fixing roller, a toner is interposed between the rotating fixing roller and a pressure roller opposed thereto. The transfer material carrying the image is held and conveyed, and the toner is heated and melted to be fused on the transfer material.

[0003] Due to recent environmental regulations and an increase in environmental protection consciousness, it has been practiced to cut off the power supply to the heat source of the fixing device when not in use and to supply power only when necessary, thereby reducing power consumption. Have been done. In such an energy saving type image forming apparatus, the surface temperature of the fixing roller needs to immediately reach the set temperature during image formation. As a means for satisfying this requirement, measures such as reducing the thickness of the fixing roller and reducing the heat capacity are taken. However, temperature control is required in view of making the temperature distribution uniform over the entire length of the fixing roller.

On the other hand, as another method, a fixing device using radiant heat has been devised. The fixing device disclosed in Japanese Patent Application Laid-Open No. Hei 5-323810 has a far-infrared lamp as a heating source, is composed of a housing provided with movable and fixed reflectors, and directly heats the transfer material by radiant heating. It is a fixing device. With this device, the rise time can be reduced. Further, the far infrared rays emitted from the far infrared lamp are efficiently absorbed by the toner, and heat and melt the toner. However, since the far-infrared lamp generates a large amount of heat, the transfer material causes conveyance failure in the fixing device,
If the light enters the housing through the opening surface and gets too close to the lamp, there is a problem that smoke is caused by overheating of the transfer material and the toner image. For this reason, sufficient consideration is required for safety measures, and the following proposals have been made.

[0005]

In the fixing device disclosed in Japanese Patent Application Laid-Open No. 6-3986, a protective net is provided at an opening of a housing provided with a far-infrared lamp to prevent the transfer material from entering the inside of the housing. I have. Patent No. 2856
In the radiation fixing device disclosed in Japanese Patent No. 343, the transfer material is guided by stretching wires above and below a transfer material transport path provided in the fixing device, and at the same time, the efficiency of heat conduction is improved. .

However, even in the above-described fixing device, if the transfer material tip is curled by heat and lifts up, the transfer material tip is caught on the protection net or the transfer material guide wire, and a conveyance failure is likely to occur. There is. The transfer material whose tip is caught is overheated by staying there and receiving radiant heat, thereby causing danger such as smoking. Therefore, further improvement is required from the viewpoint of safety as well as the transport efficiency.

In view of the above problems, the present invention enables stable transfer of a transfer material in an image forming apparatus provided with a fixing device using radiant heat in order to prevent transfer material overheating due to transfer material transfer failure. Accordingly, it is an object to provide an image forming apparatus including a fixing device capable of fixing a uniform toner image.

[0008]

According to a first aspect of the present invention, a transfer material carrying a toner image is transported to a fixing device by a transport member, and the transfer material is radiated on the transfer material by radiant heat. An image forming apparatus having a fixing device that forms a permanent image on the surface of a transfer material by heating, wherein the conveying member includes a plurality of endless wires. According to a second aspect of the present invention, there is provided the image forming apparatus according to the first aspect, wherein a wire is coated with heat-resistant rubber in the conveying member.

According to a third aspect of the present invention, there is provided a fixing device in which a transfer material carrying a toner image is conveyed to a fixing device by a conveying member, and the transfer material is heated by radiant heat to form a permanent image on the surface of the transfer material. In the image forming apparatus having the transfer member, the transfer member is a member that comes into contact with the back of the toner image on the transfer material, and a transfer auxiliary member is disposed on the toner image surface side of the transfer material. 3. The image forming apparatus according to claim 1, wherein the discharge assisting member is narrower than the inlet portion, and the transport auxiliary member includes a plurality of endless wires. 4. According to a fourth aspect of the present invention, there is provided the image forming apparatus according to the third aspect, wherein the surface of the wire is coated with a heat-resistant resin in the transport assisting member. According to a fifth aspect of the present invention, there is provided the image forming apparatus according to the third or fourth aspect, wherein the transport assisting member is disposed at an angle with respect to a transfer material transport direction. The invention according to claim 6 is characterized in that the speed component of the transfer auxiliary member in the transfer material transfer direction is at least a speed equal to or higher than the transfer speed of the transfer member. The image forming apparatus described in (1).

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram of an image forming apparatus according to an embodiment of the present invention. A charging means 2, a cleaning device 3, a laser beam L by a laser optical system, and a developing sleeve 5 for supplying toner around the photosensitive member 1 rotating in the direction of arrow a to visualize the latent image on the photosensitive member 1. , A transfer device 6 and the like.
Further, the transfer material P in the detachable paper feed cassette 10 which is disposed on the lower side is supported by the middle plate 11 and pressed against the paper feed roller 13 via the arm 12 by the force of a spring (not shown). When a command is issued from a control unit (not shown) and the sheet feeding roller 13 rotates, the sheet feeding cassette 1 is rotated.
The transfer material at the top in 0 is transported to the registration roller 15 on the downstream side while preventing double feed by the separation pad 14,
The timing is set so as to synchronize with the image on the photoreceptor 1, and the transfer material is sent out toward the transfer means 6. The transfer material obtained from the photoreceptor 1 by the transfer means 6 is further conveyed to the fixing means 16 and heated and melted to fix the toner image. Thereafter, the transfer material on which the image has been formed is discharged to the discharge rollers 20.
As a result, the sheet is discharged and placed on the sheet discharge tray section 22 from the sheet discharge port 21. The ejection stopper is movable in the direction of arrow b in order to correspond to the size of the ejected transfer material. An operation surface is disposed on the right side, and an operation panel 30 protrudes from an upper front surface of the exterior unit 31.

The non-contact type fixing device utilizing radiant heat of the present invention may be used alone, or may be used together with a contact type fixing device having a pair of rollers. In this case, it is possible to adopt a configuration in which the transfer material is preliminarily heated by the non-contact type fixing device, and is pressed and fixed by the contact type fixing device.

(First Embodiment) FIG. 2 is a diagram showing a configuration of a fixing device according to a first embodiment of the present invention. The far-infrared heating unit 101 and the reflection plates 102a and 102b are arranged as shown in FIG. On the reflection plate 102a side, the transfer material 106
A protection net 111 is provided in order to prevent the intrusion into the far-infrared ray heating section 101. The transfer material 106 is conveyed by rotating the conveyance pulley 110 from a rotation drive source (not shown) and driving the conveyance member 104, and the unfixed toner image 107 is heated and melted by radiant heat. The transfer material 106 carrying the heat-fused unfixed toner image is transferred to the transport member 1
04 guide member 1 at the entrance of the calendar roller 105
08 to be held in pressure contact. Molten toner is transfer material 1
The anchor is anchored at 06 and the surface can obtain a gloss similar to that of the calender roller 105.

The timing of the fixing operation is as follows. When a printing signal is input to the controller board after the power of the apparatus is turned on, the maximum power is supplied to the heating sources 109 of the pair of calender rollers 105, and a preheating operation of heating to a predetermined temperature is performed. In synchronization with the preheating state, the above-described series of image forming processes is operated, an unfixed toner image 107 is formed on the transfer material 106, and the transfer member 104 guides the unfixed toner image 107 to the guide member 108 at the entrance of the calender roller 105. At this point, the calendar roller 105 is set so as to reach a predetermined temperature. Similarly, heating means A
Is synchronized with the operation of the imaging process, and the far-infrared heating unit 101
At the timing when the rear end of the transfer material 106 has passed through the conveying member 104.

Here, the transport member 104 is provided with a plurality of endless metal wires parallel to the transfer material 106 transport direction. With such a wire, it is difficult for the conveying member in contact with the back surface of the transfer material to take away the heat on the transfer material obtained by the radiant heat, thereby preventing a fixing failure. Further, by coating the metal wire of the transfer member with heat-resistant rubber such as silicone rubber, heat transfer to the transfer member can be reduced.

(Second Embodiment) FIG. 3 is a diagram showing a configuration of a fixing device according to a second embodiment of the present invention. The fixing device according to the first embodiment has a configuration in which a conveyance auxiliary member 104b is provided. The transport member 1 is rotated by rotating the transport pulleys 110a and 110b from a rotation drive source (not shown).
04a and the transport assisting member 104b to drive the transfer material 10
6, and the unfixed toner image 107 is heated and melted by radiant heat. Subsequently, the transfer material 106 is transported to the guide member 108 at the entrance of the calendar roller 105.

Here, the transport assisting member 104b has a plurality of endless metal wires provided in parallel to the transport direction of the transfer material 106. Transfer material 106 is far infrared heating unit 10
Intrusion in one direction can be prevented, and the safety of the fixing device can be ensured. Further, the transport member 104a and the transport auxiliary member 104b
Are narrower at the discharge port than at the transfer material entrance site. This is to prevent the transfer material from being rolled up and causing conveyance failure when the transfer material tip is curled by heat.

The metal wire of the transport assisting member 104b is
It can be covered with a heat-resistant resin such as a fluororesin. Thus, even if the transfer material is warped by heat and comes into contact with the transport auxiliary member, the unfixed toner image can be less likely to adhere to the transport auxiliary member.

Further, as shown in FIG.
04b may be configured to have an angle with respect to the transport member 104a. With this configuration, when the far-infrared rays emitted from the far-infrared heating unit reach the transfer material, the portion blocked by the transport assisting member 104a is reduced, and the toner image on the transfer material is fixed more uniformly. Can be made.

The speed component of the transfer auxiliary member in the transfer material transfer direction may be the same as the transfer speed of the transfer member, or may be higher. Depending on the moisture absorption state of the transfer material, the radiant heat is quickly transferred by the heating means A, the moisture evaporates, and the transfer material may curl. At this time, the tip of the transfer material
The sheet is conveyed to a position where the distance between the conveying member and the conveying auxiliary member is reduced, and is brought into contact with the conveying auxiliary member. It is preferable that the speed component of the auxiliary member in the transport direction is higher than the transport speed of the transport member.

[0020]

As described above, in a fixing device in which a transfer material carrying a toner image is conveyed to a fixing device by a conveying member and the transfer material is heated by radiant heat to form a permanent image on the surface of the transfer material. By adopting a configuration in which the transport member is composed of a plurality of endless metal wires, the transport member in contact with the back surface of the transfer material is less likely to deprive the heat on the transfer material obtained by radiant heat, preventing poor fixing and uniform fixing. Becomes possible. Furthermore, in addition to the transport member, an auxiliary transport member made of an endless metal wire is provided, and the interval between the transport member and the transport auxiliary member is narrower at the discharge outlet than the transfer material inlet portion, so that the curl starts receiving radiation heat. The transfer material tip
Stable transport becomes possible.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a fixing device according to the first embodiment.

FIG. 3 is a diagram illustrating a configuration of a fixing device according to a second embodiment.

FIG. 4 is a diagram illustrating an arrangement of a conveyance assisting member in a fixing device according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging means 3 Cleaning device 5 Developing sleeve 6 Transfer means 7 Developing device 10 Paper feed cassette 11 Middle plate 12 Arm 13 Paper feed roller 14 Separation pad 15 Registration roller 16 Fixing device 18 Heat fixing roller 19 Pressure roller 20 Discharge Paper roller 21 Discharge port 22 Discharge tray unit 30 Operation panel 31 Exterior unit 101 Far infrared heating unit 102a, 102b Reflector 104, 104a Transport member 104b Transport assist member 105 Calendar roller 106 Transfer material 107 Unfixed toner image 108 Guide member 109 Heat source 110a, 110b Transport pulley 112 Intermediate transport member L Laser beam P Transfer material

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Jun Yura 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (reference) 2H033 AA14 AA42 BA01 BA11 BA12 BA35 BC02 BC03 CA36 2H072 HA00 HB05 JA01 JA04 3F049 AA01 BA11 LA01 LB03

Claims (6)

[Claims] An image forming apparatus having a fixing device that conveys a transfer material carrying a toner image to a fixing device by a conveying member and heats the transfer material by radiant heat to form a permanent image on the surface of the transfer material. An image forming apparatus, wherein the conveying member comprises a plurality of endless wires. 2. The image forming apparatus according to claim 1, wherein a wire is coated with heat-resistant rubber in the conveying member. 3. An image forming apparatus having a fixing device for conveying a transfer material carrying a toner image to a fixing device by a conveying member and heating the transfer material by radiant heat to form a permanent image on the surface of the transfer material. The conveying member is a member that comes into contact with the back of the toner image on the transfer material, and a conveying auxiliary member is arranged on the toner image surface side of the transfer material. The image forming apparatus according to claim 1, wherein the transport assisting member is narrowly arranged, and the transport auxiliary member includes a plurality of endless wires. 4. The image forming apparatus according to claim 3, wherein a surface of the wire is coated with a heat-resistant resin in the transport assisting member. 5. The transfer assisting member according to claim 3, wherein the transfer assisting member is arranged at an angle with respect to a transfer material transfer direction.
Or the image forming apparatus according to 4. 6. The image according to claim 3, wherein a speed component of the transfer auxiliary member in the transfer material transfer direction is at least a speed equal to or higher than the transfer speed of the transfer member. Forming equipment.