JP3331785B2 - 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 provided with a release agent supply device for supplying a release agent (oil) to a fixing roll or a pressure roll.

[0002]

2. Description of the Related Art This type of fixing device will be described with reference to FIG.
The release agent supplied to the fixing roll 1 is stored in an oil pan 2. Then, the end of the oil wick 3 having the contact portion 4 on the fixing roll 1 is inserted into the oil pan 2, the release agent is sucked up by capillary action, and the oil is applied directly from the contact portion 4 to the fixing roll 1. ing. The metering blade 5 scrapes off the oil by bringing the tip into contact with the roll surface, and controls the amount of the release agent applied to the paper.

In the device configured as described above, the amount of the normal oil corresponding to the oil consumed from the contact portion 4 is supplied to the oil pan 2 as fresh oil from a supply device (not shown). ing. Since the oil pan 2 is disposed adjacent to the fixing roll 1, the oil in the oil pan 2 is constantly heated by the radiant heat of the fixing roll 1. In such a state, in a copying machine or a printer in which the consumption of the release agent is relatively small, if no oil is consumed, no new oil is supplied and the oil is kept in the oil pan for a long time. severe thermal degradation depending on the type, performance degradation of the release agent spawning
As a result, the releasability of the fixing roll itself was reduced, which caused image quality defects and paper jams. further,
The configuration in which the oil wick 3 comes into direct contact with the fixing roll 1 and applies the release agent is performed by using a minute offset toner or a toner on the paper when a paper jam occurs.
Was contaminated, causing uneven application of the release agent, which eventually resulted in image quality defects and paper jams.

Japanese Patent Application Laid-Open No. Sho 59-100478 discloses a configuration in which oil assembled by a pump is directly dropped on the surface of a roll from an oil supply nozzle disposed above the roll in order to avoid the influence of heat of the fixing roll. However, depending on the location and spacing of the nozzles, there may be areas where the oil is not applied to the surface of the fixing roll, or in high-speed copiers and printers that consume a relatively large amount of release agent. Insufficient oil was supplied with respect to the release agent consumed at both ends of the roll, and the release property of the fixing roll was reduced, causing image quality defects and paper jams.

[0005]

Therefore, the present invention enables uniform and rapid supply of the release agent to the heating and pressure rolls even in a high-speed machine that consumes a relatively large amount of the release agent. If the release agent is supplied evenly over the entire image area ,
In addition, the release agent is avoided from the effects of heat, and the thermal degradation of the release agent
The present invention provides a fixing device capable of preventing the occurrence of a flaw.

[0006]

Means for Solving the Problems The fixing device of the present invention comprises:
A heating roll that rotates, and a pressure roll that presses against the heating roll, heats and presses an unfixed toner image on paper to fix the image, and at least one of the heating roll and the pressure roll in the fixing device provided with a release agent supply device for forming a clock-receiving portion release agent supplying a release agent, the release agent supply device accommodates a release agent, prior to
Serial heating roller and disposed parallel to and a cylindrical body provided with an oil pump for supplying a release agent to said tubular body, the release
The part to be supplied with the agent is at least the heating roll or
Donor roll that supplies a release agent to one of the pressure rolls
And the cylindrical body is spaced apart from the heating roll and the pressure roll, and
Disposed on top, and has a plurality of holes drilled axially upper surface, the release agent from the plurality of holes of the cylindrical body, wherein
A configuration is provided in which a part to be supplied with a release agent flows on the outer peripheral surface of the cylindrical body and is dropped.

[0007]

The release agent supplied from the oil pump overflows from the hole formed in the upper surface of the cylindrical body, and is dripped from the lower part of the hole over the entire length of the cylindrical body at the same time as the operation of the oil pump.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the fixing device of the present invention will be described with reference to the drawings. First Embodiment FIG. 1 is a schematic diagram of a fixing device provided with a release agent supply device. In a fixing device having a heating roll 10 having a heating source therein and a fixing unit having a pressure roll 20 pressed against the heating roll 10, a releasing agent such as silicone oil (hereinafter referred to as oil) is applied to the heating roll 10. Is supplied to the roll surface so as to contact and rotate. Further, a metalling roll 40 for controlling the amount of oil to be supplied comes into contact with the donor roll 30, and a metalling blade 45 for controlling the amount of oil of the metalling roll 40.
Are in contact with the metering roll 40. An oil wick 50 is disposed upstream of the contact portion of the metering roll 40 with the metering blade 45. Oil wick 5
Numeral 0 has a contact portion 55 that comes into contact with the metering roll 40, and has an inclined upper guide portion 53 and a lower guide portion 57 at the upper and lower portions.

A pipe 60 for containing oil is provided on the contact portion 55 of the oil wick 50 or on the upper portion of the upper guide portion 53. The oil storage pipe 60 is a cylindrical body, and has a hole 65 at the top. A plurality of holes 65 are provided in the axial direction (seven in this embodiment), the diameter of the holes 16a and 16b provided at one end is 0.8φ, and the diameter of the next two holes 16c and 16d is Is set to 1.0φ, and the hole diameters of the next three holes 16e, 16f, and 16g are set to 1.2φ. That is, the hole diameter is gradually increased from one end to the other end. The oil storage pipe 60 is provided in parallel with the axial direction of the heating roll 10. Oil storage pipe 60 has hole 6
The connecting pipe 75 connected to the oil pump 70 is connected to the side end surface 67 where the small hole 5a of 5 is provided. Oil pump 70 communicates with oil tank 77 .

The fixing device constructed as described above receives the detection signal from the detecting means for detecting the sheet passing through the heating roll 10 and the pressure roll 20, and receives the oil pump 7 for a certain period of time.
0 is activated, and a constant amount of oil is supplied to the oil pipe 60. Oil is oil pipe 6
0, the oil in the pipe 60
It overflows from a hole 65 drilled on the upper surface (top), passes through the outer peripheral wall surface of the pipe 60, and drops on the surface of the metering roll 40 or the oil wick 50, which is the oil supply portion.

The oil applied to the surface of the metalling roll 40 is applied to the surface of the heating roll 10 via the donor roll 30. In this case, the discharge amount of the oil pump 70 is set to a slightly larger amount than the amount of oil absorbed by the paper and consumed. Then, the surplus oil is scraped off by the metering blade 45, flows down the oil pan 73, and is collected in the oil tank 77. The collected oil is discharged again by the oil pump 70 and reused.

Next, the state of oil dripping from the oil pipe 60 will be described (see FIG. 3). Oil from the oil pump 70 is supplied from the connecting pipe 75 into the pipe 60.
The surplus oil in the pipe 60 overflows from the hole 65 formed in the upper part of the pipe 60, flows down the water dividing line of the pipe 60, flows down to the lower part of the pipe 60 as shown by the arrow, and drops. At this time, the upstream holes 65a and 65b through which the oil flows into the pipe 60 are replaced with the downstream holes 65f and 6b.
Since the hole diameter is smaller than 5 g, the amount of oil overflowing from each hole is almost the same. The oil is supplied to the pipe 60
The droplets spread over the entire peripheral wall and flow down, so that the droplets to be dropped have a constant size at short intervals. Further, even if foreign matter enters the oil pipe 60, the foreign matter sinks to the bottom of the pipe, so that the hole 65 is unlikely to be clogged.

As described above, in the fixing device provided with the release agent supply device shown in this embodiment, the oil pipe 60 for containing the oil is disposed above the heating roll 10 which is the oil supply portion at an interval. Thus, by avoiding the influence of heat and shortening the holding time of the oil in the oil wick 50, thermal deterioration of the oil is prevented. Also,
The oil supply from the oil pump 70 is set to be larger than the oil consumption so that the oil on the roll surface does not die,
Further, when the oil pump 70 is operated, uniform oil droplets are simultaneously dripped over the entire area of the roll 10 in the axial direction, so that the oil can be supplied uniformly.

REFERENCE EXAMPLE This reference example shown in FIG. 4 simplifies the structure of a release agent supply device. A metering blade 450 that controls the amount of oil in the heating roll 10 of the fixing unit constituted by the heating roll 10 and the pressure roll 20 is disposed in direct contact with the heating roll 10. The metering blade 450 is inclined at an angle such that the oil scraped off by the blade can stay at a fixed amount at the blade edge at the contact surface and the oil can flow toward the oil pan 730 containing the scraped oil. Is arranged. The oil pipe 60 is disposed above the contact portion of the metering blade 450 with the roll 10 surface or above the upstream portion of the heating roll 10 in parallel with the roll axis direction.

In the fixing device configured as described above, the pump 70 operates for a certain time in response to a signal from a sensor for detecting a sheet passing between the heating roll 10 and the pressure roll 20. The oil discharged from the pump 70 is supplied to the oil pipe 60 through a supply pipe 75, and is formed in a hole 6
Overflowing from 5. The oil flows on the outer peripheral surface of the pipe 60 and drops on the surface of the heating roll 10. Since the amount of oil supplied is controlled more than the amount consumed on paper,
Excess oil is scraped off by the metering blade 450,
A certain amount of the oil stays at the contact portion between the blade edge and the roll surface, and this oil is supplied directly to the roll surface as the heating roll 10 rotates. Then, the oil that has been further scraped down flows down the inclined surface of the blade 450, flows to the oil pan 730, and is collected in the oil tank 77. Then, the collected oil is discharged again by the oil pump 70 and reused.

As described above, the fixing device in this reference example eliminates the oil wick that holds the release agent in a fixed amount and supplies it to the heating roll 10, thereby simplifying the device and releasing the agent (oil). Thermal degradation due to the heat of the heating roll is minimized.

[0017]

As described above, the fixing device of the present invention
The pipe containing the release agent is arranged at a distance from the heating roll and the pressure roll to avoid the release agent from the influence of heat,
Thermal degradation is prevented. Further, since the supply hole of the release agent is disposed on the upper surface of the pipe with respect to the supplied portion, uniform release agent droplets can be formed, and the release agent in the roll axis direction can be formed. Simultaneous supply is possible, and even supply is possible to the entire image area, and high-quality images can be provided. further,
In a high-speed machine that consumes a large amount of toner, uniform release agent supply can be achieved, so that the release maintaining performance of each fixing roll is high and the life of the roll can be extended. In addition, since thermal degradation can be minimized, even a release agent that is thermally degraded by radiant heat can be used.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a fixing device.

FIG. 2 is a perspective view of an oil pipe.

FIG. 3 is an explanatory diagram of an oil flow state of an oil pipe.

FIG. 4 is a reference example of a fixing device.

FIG. 5 is an explanatory view showing a conventional example of a release agent supply device.

[Explanation of symbols]

Reference Signs List 10 heating roll, 20 pressure roll, 30 donor roll, 40 metering roll, 45 metering blade, 50 oil wick, 60 oil pipe, 65 holes, 70 oil pump, 73
Oil pan, 77 oil tank.

────────────────────────────────────────────────── ─── Continuation of the front page Examiner Kiyozumi Yazawa (56) References JP-A-2-236578 (JP, A) JP-A-60-129768 (JP, A) JP-A-59-100478 (JP, A) Kaihei 6-274061 (JP, A) Japanese Utility Model Showa 50-78230 (JP, U) Japanese Utility Model Showa 60-176459 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15 / 20

Claims (2)

(57) [Claims] A heating roller configured to heat and press an unfixed toner image on a sheet to fix the unfixed toner image on a sheet of paper; In a fixing device including a release agent supply device that forms a release agent supply portion that supplies a release agent to one of the rolls, the release agent supply device contains a release agent, and the heating device A cylindrical body disposed in parallel with the roll ; and an oil pump for supplying a release agent to the cylindrical body, wherein the part to which the release agent is supplied is at least the heating roll.
Or, a supply of release agent to one of the pressure rolls
A plurality of rolls having a knurled roll, the tubular body being disposed at an interval from the heating roll and the pressure roll, and being disposed above the release agent-supplied portion, and piercing the upper surface in the axial direction. has a number of holes, the releasing agent is a plurality of holes of the cylindrical body, the said release agent
A fixing device, wherein the fixing device flows onto an outer peripheral surface of the cylindrical body and is dropped on a supply portion . 2. The cylindrical body according to claim 1, wherein the diameter of the hole provided at the oil pump communication side end is reduced, and the diameter of the hole provided toward the other end in the axial direction is sequentially increased. Fixing device.