JP2003066753A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of uneven oil on an image resulting from an oil pool D caused by a shock during the fixing engagement of a cardboard without necessitating a cost or a space in an image forming apparatus having a releasing agent coating means 40 to coat the surface of a fixing means 4a with a releasing agent O. SOLUTION: The image forming apparatus comprises an image forming means to form an image on a sheet, a fixing means 4a to heat or pressurize the sheet on which the image is formed so as to fix the image, the releasing agent coating means 40 to coat the surface of the fixing means with the releasing agent O, a regulating means 44 to regulate the quantity of the releasing agent, a vibration generating means to give vibration to the regulating means, and a control means which adjusts the vibration generation timing of the vibration generating means so that an uneven releasing agent caused by the vibration means comes between the sheets of the sheets to be continuously fixed.

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 a printer, a facsimile, a copying machine, or a multi-function peripheral having these functions.

[0002]

2. Description of the Related Art For example, in an image forming apparatus such as a copying machine, a printer or a facsimile, a recording material (transfer material, photosensitive paper or the like) is formed by an appropriate image forming process mechanism such as an electrophotographic method, an electrostatic recording method, a magnetic recording method. A device for thermally fixing an unfixed toner image formed and carried on a recording material such as an electrostatic recording paper or a printing paper) by a transfer method (indirect method) or a direct method corresponding to target image information as a permanently fixed image. Is widely used.

As such a fixing device, a device for applying a silicone oil as a releasing agent on a fixing roller which is a fixing means in order to improve the releasing property of a sheet which is a recording material from the fixing means and prevent a jam. Is the mainstream. Some examples are given below.

1) Cleaning the fixing roller A cleaning web is impregnated with silicon oil, and oil is applied simultaneously with cleaning the fixing roller.

2) A roller or felt impregnated with silicon oil is brought into contact with the fixing roller.

3) A large amount of oil is drawn from the oil pan by the drawing roller, and while the oil is being transferred to the plurality of rollers, the amount of oil is regulated by the blade in the middle of the process and the oil is applied onto the fixing roller.

4) Same as 3) above, but instead of the oil pan, the oil pumped is directly supplied onto the pumping roller.

There is a device such as

The above examples 1) and 2) are used for monochrome output machines and color output machines with relatively low productivity. The examples 3) and 4) are used for a color output machine having a relatively high productivity.

The example 3) will be described in detail below.
In FIG. 8, 4a is a fixing roller as a fixing unit, and 4a is a fixing roller.
Reference numeral b denotes a pressure roller as a pressure means, which is made by fixing silicon rubber to the surface layer of an aluminum cored bar,
The fixing nip portion N is formed by vertically arranging them in parallel and bringing them into pressure contact with each other with a predetermined pressing force. Both rollers 4a
4b is rotationally driven at a predetermined peripheral speed in the direction of the arrow by a drive system (not shown). 45a and 45b are fixing rollers 4a
And a halogen heater, which is a heating source disposed inside the core of each roller of the pressure roller 4b, and the fixing rollers 4 and 47.
a is a thermistor arranged in contact with the surface layer of silicon rubber of each roller of the pressure roller 4b.

The fixing roller 4a and the pressure roller 4b are heated by the halogen heaters 45a and 45b, and the thermistors 46 and 47 detect the surface temperature of the rollers. The controller unit (not shown) is each thermistor 46.
The temperature detected by 47 is compared with a preset temperature. If the temperature is lower than the set temperature, the halogen heaters 45a and 45b are turned on via the AC driver, and if the temperature is higher than the set temperature, the halogen heaters 45a and 45b are controlled not to be turned on. 4a and pressure roller 4b
The temperature control is performed so that each of the temperatures is maintained at a predetermined constant value.

The sheet on which the unfixed toner image t is formed and carried in a state in which the fixing roller 4a and the pressure roller 4b are rotationally driven and the temperatures of the fixing roller 4a and the pressure roller 4b are adjusted to predetermined temperatures. S is introduced into the fixing nip portion N such that the unfixed toner image carrying surface side faces the fixing roller 4a, and is nipped and conveyed. In the process in which the sheet S is nipped and conveyed through the fixing nip portion N, heat and pressure are applied to the unfixed toner image t on the surface of the sheet S to be fused or fixed as a permanently fixed image on the surface of the sheet S. .

Reference numeral 40 denotes an oil applying roller as a releasing agent applying means for applying silicone oil as a releasing agent to the fixing roller 4a, which is brought into contact with the fixing roller 4a. The silicone oil O in the oil pan 65 is supplied to the oil applying roller 40 via the first to third pumping rollers 43, 42 and 41.

That is, a part of the first pumping roller 43 is immersed in the oil O in the oil pan 65,
The second pumping roller 42 is attached to the first pumping roller 43.
Adjacent to each other, and the third pumping roller 41 is adjacent to the second pumping roller 42.
Is adjacent to the oil applying roller 40. The second pumping roller 42 is rotationally driven in the direction of the arrow from the drive source M via the transmission system, and from there, the third pumping roller 4 is driven.
1, and the drive is transmitted to the coating roller 40, which is a release agent coating means, via the first scooping roller 43 to rotate the rollers 43, 41, 44 in the directions of the arrows. . In this way, the oil applying roller 4
0 is supplied with the oil O sequentially transferred from the oil pan 65 by the three first to third scooping rollers 43, 42, 41, and the oil is applied to the surface of the fixing roller 4a by the oil applying roller 40. To be done.

Further, a metering blade 44 serving as a release agent regulating means made of an elastic material such as fluororubber urged by a spring (not shown) so that a constant pressure is always maintained against the oil applying roller 40. Are in contact with each other and regulate the amount of oil on the oil applying roller 40 to a predetermined value. The regulated oil on the oil applying roller 40 is transferred to the fixing roller 4a at the oil applying portion which is the contact portion between the oil applying roller 40 and the fixing roller 4a.

[0016]

[Problems to be Solved by the Invention] In recent years,
Even in such an image forming apparatus, it is desired to handle not only so-called copy paper but also various kinds of sheet materials. As one of them, thick paper (150 g / m ² or more)
However, in order to fix thick paper having a large heat capacity, the pressing force of the fixing roller is an important condition as well as the amount of heat applied to the sheet S, and it is necessary to increase the pressing force.

However, as an adverse effect of increasing the pressing force, at the moment when the leading edge of the sheet S (particularly thick paper) is pinched by the fixing nip portion T which is the pressure contact portion between the fixing roller 4a and the pressure roller 4b as shown in FIG. However, the driving load increases significantly. As a result, the rotation fluctuation of the motor itself and the fixing roller 4
When the drive transmission path up to a is long, the rotational fluctuation of the fixing roller 4a is likely to occur due to the accumulation of minute flexures and deformations of the drive system.

FIG. 11 is a graph showing fluctuations in the rotation of the fixing roller 4a. The horizontal axis represents time t, and the vertical axis represents the peripheral speed V of the fixing roller 4a. The rotation fluctuation when pinched is shown. As shown in the figure, the peripheral speed drops once as the load rapidly increases. The load decreases when the fixing roller 4a gets over the leading edge of the sheet,
The peripheral speed rises from the steady speed due to the reaction of the drive system that is bent when the load increases. After that, the rotation fluctuation is attenuated and returns to the steady speed.

When this rotation variation occurs, the oil application roller 40 is also driven and transmitted from the same drive source as the fixing roller 4a, so that the oil application roller 40 also undergoes the rotation variation. Therefore, the following bad phenomena occur.

That is, as described with reference to FIG. 8, the oil O which is sequentially delivered from the oil pan 65 by the three first to third scooping rollers 43, 42, 41 is supplied to the oil applying roller 40. The oil supplied to the oil application roller 40 is regulated by the metering blade 44 on the oil application roller 40, but the regulated oil is steadily maintained between the edge portion of the metalling blade 44 and the oil application roller 40. A minute oil pool D is formed during rotation (over the entire length).

This oil pool D is a metering blade 4
It is formed with a balance due to the amount of oil slipping through from 4, the surface tension, the oil viscosity, the gravity, etc. However, if vibration such as the uneven rotation described above is applied, the balance is lost at that moment, The oil sump D is shown in FIG.
Is discharged onto the oil applying roller 40 as described above.

The discharged oil in the oil reservoir D is transferred to the fixing roller 4a side at the contact portion between the oil applying roller 40 and the fixing roller 4a, and is carried to the fixing nip portion N as shown in FIG. It is transferred in the form of streaks as an excessive oil mark on the sheet S being nipped and conveyed through the nip portion N. The position corresponds to the length L from the metering blade 44 to the fixing nip portion N measured from the leading end of the sheet S.

If the amount of the oil streaks is small, there is no problem on the image. However, if the amount is large, the oil streaks appear in the image as uneven gloss or color unevenness and deteriorate in proportion to vibration such as rotation fluctuation.

In order to suppress such rotational fluctuation, there is a method in which a flywheel is provided on the drive system in order to increase the inertial force of the fixing roller 4a. Therefore, in order to avoid the influence of the bending of the drive system, the effect cannot be obtained unless the flywheel is attached near the fixing roller. However, since the rotation speed is low near the fixing roller, a very large flywheel is required, resulting in a large space.

Further, the fixing roller itself will be damaged if it is not stopped immediately when it is jammed.
Brake means for stopping the roller is required, which has the adverse effect of increasing the cost.

Alternatively, there is a method of strengthening the drive system itself so as not to cause bending, but it is still necessary to sacrifice considerable cost and assembly.

Therefore, in the present invention, in an image forming apparatus having a releasing agent applying means for applying a releasing agent to the surface of the fixing means, a shock when the fixing paper is caught in the thick paper causes an oil unevenness on the image caused by the oil pool. The purpose of this is to prevent the occurrence of the above without increasing the cost or the space.

[0028]

The present invention is an image forming apparatus characterized by the following means.

(1) Image forming means for forming an image on a sheet, fixing means for fixing the image by heating or pressurizing the sheet on which the image is formed, and release for applying a release agent on the surface of the fixing means. Agent coating means, regulating means for regulating the amount of the releasing agent, vibration generating means for vibrating the regulating means, and unevenness of the releasing agent generated by the vibrating means between the sheets which are continuously fixed. Image forming apparatus having a control unit that adjusts the vibration generation timing of the vibration generation unit.

(2) The release agent applying means is a rotating member that rotates adjacent to the fixing means, and the vibration generating means is an intermittent drive force transmitted to the rotating member. (1) The image forming apparatus.

(3) Intermittent driving force is the motor OFF / O
(2) The image forming apparatus according to (2), characterized in that N is performed.

(4) The image forming apparatus according to (2), characterized in that the driving force is interrupted by turning off / on the clutch in the driving system.

(Operation) That is, an image forming apparatus such as a printer, a facsimile machine, a copying machine, or a multi-function machine having these functions, and having a releasing agent applying means for applying a releasing agent to the surface of the fixing means. With regard to the above, a vibration generating means for giving vibration to the regulating means for regulating the amount of the releasing agent is provided, and the unevenness of the releasing agent generated by the vibrating means is set so that the unevenness of the releasing agent is continuously applied between the sheets. Adjusting the vibration generation timing of the vibration generating means, that is, the release agent accumulated in the vicinity of the release agent regulating means is timed by the forced vibration means so that it is between the sheets, and the release agent is discharged to form a sheet. By preventing transfer, even on sheets such as thick paper that vibrate the fixing means, it is possible without cost and space to prevent image unevenness. .

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] (FIGS. 1 to 5) (1) Example of Image Forming Apparatus FIG. 1 is a schematic configuration diagram of an image forming apparatus equipped with a fixing device according to the present invention. The image forming apparatus of this example is a color laser printer using a transfer type electrophotographic process.

When the document G is placed and set on the document table glass 11 of the reader unit 1 with the image surface facing downward and the printer is started, the moving scanning optical system 12 and the reduction lens 1
3, the reading function section including the CCD array 14 photoelectrically reads the original image. The document image information is photoelectrically converted, A / D converted, and then transferred to the memory. The reading function unit has a color separation reading function for a color image.
The maximum document size is LTR or A3.

An image forming unit 2 includes a cyan toner image forming unit, a magenta toner image forming unit,
Four image forming units, that is, a yellow toner image forming unit and a black toner image forming unit, are arranged on the upper side of the sheet conveying belt 28 arranged substantially horizontally in order from the upstream side to the downstream side in the sheet conveying direction. . Each image forming unit includes an electrophotographic photosensitive drum 23, a charger 24,
It has a developing device 25, a cleaning device 27, and the like.

Reference numeral 21 denotes a laser emitting section controlled by a laser driver, which emits a laser beam modulated corresponding to a time-series electric digital pixel signal of the original image read by the reader section 1. Then, the polygon mirror 22 is rotated to scan in the generatrix direction of the photosensitive drum 23 of the image forming unit, and a latent image is formed on the surface of the photosensitive drum 23 which is charged in advance by the charger 24. This latent image is developed by the developing device 25 provided around the photosensitive drum 23. In the case of a color image, the image forming unit forms a cyan toner image, the image forming unit forms a magenta toner image, the image forming unit forms a yellow toner image, and the image forming unit forms a black toner image.

The sheet S as the recording material fed from the side of the paper feeding unit 3 is fed by the registration rollers 29 to the feeding belt 28 at a predetermined control timing, and is sequentially fed through the image forming units. In the process, four toner images of a cyan toner image, a magenta toner image, a yellow toner image, and a black toner image are sequentially and multiple-transferred by the transfer charger 26, and a color toner image is synthetically formed.

Sheet S in each image forming unit
The toner remaining on the surface of the photosensitive drum 24 after the transfer of the toner image is removed by the cleaning device 27.

When the sheet S on which the toner image is transferred in the image forming section 2 is guided to the fixing device 4 by the conveyor belt 8 and passes through the fixing nip portion N which is the pressure contact portion between the fixing roller 4a and the pressure roller 4b. The toner image is fused, that is, fixed on the sheet S by applying heat and pressure to the sheet. The sheet S that has undergone the fixing process is discharged to the discharge tray 5.

The paper feeding unit 3 is provided below the image forming unit 2 and is provided with two upper and lower parts.
It has a plurality of paper feed points, the first and second paper feed cassettes 31 and 32 that are detachably attached to the stack, a large capacity paper feed deck 33, and a manual paper feed section 34. One sheet S can be separated and fed from the paper part.

The sheet S is separated and fed one by one from each sheet feeding point as follows. A solenoid (not shown) connected to the pickup roller 35 is turned on when the solenoid is on standby.
The pickup roller 35 is separated from the sheet surface. The next time the sheet is fed, the solenoid will turn off.
The FF is performed, and the pickup roller 35 contacts the sheet surface.
Then, the pickup roller 35 which is rotationally driven.
To feed the first sheet. The drive of the pickup roller 35 is transmitted from the conveying roller 36 via the timing belt.

The sheet picked up is conveyed by the conveying roller 3
6 and the retard roller 37 nip and convey. The conveyance roller 36 is rotationally driven in the sheet conveyance direction, and the retard roller 37 is rotationally driven in the opposite direction to the conveyance direction via a torque limiter (not shown). Therefore, since there is only one sheet between the rollers 36 and 37 on the leading edge side of the first sheet, the torque limiter loses the frictional force between the sheet and the rollers, and the retard roller 37 rotates in the conveying direction. Next, when the sheets overlap and reach the nip portion of the rollers 36 and 37, the frictional force between the first and second sheets is lost by the torque limiter and the retard roller 37 reverses in the conveying direction. , Only the uppermost sheet is separated and fed first. Even if a plurality of sheets S are picked up, the same operation causes only the uppermost one sheet to be separated and fed in advance.

By the paper feeding operation as described above, it is possible to feed the stacked sheets one by one.

Any of the above-mentioned sheet feeding points 31.3 of the sheet feeding section 3
The leading edge of the sheet S fed by 2.33, 34 is temporarily stopped by the registration roller 29, and the sheet S is fed again according to the image formed by the image forming section 2 and the image is transferred by the transfer section. . The rotation of the registration roller 22 is performed by connecting a clutch (not shown), and its control is controlled by the controller of the main body.

This printer also has a double-sided printing function using the intermediate tray section 38, but since it is outside the gist of the invention, its explanation is omitted.

(2) Fixing Device 4 FIG. 2 is a schematic view of a main part of the fixing device 4 portion. FIG. 8 above
The same members and portions as those of the fixing device of FIG.

The sheet S introduced into the fixing device 4 by the conveyor belt 8 is guided by the guide 75 and enters the fixing nip portion N.

In the oil applying mechanism portion for the fixing roller 4a, the above-mentioned oil pan 65, the first to third scooping rollers 43, 42 and 41, the oil applying roller 40,
The metering blade 44 and the like are assembled to a fixing device chassis (not shown), and the fixing device chassis is swingably supported around the shaft of the second scooping roller 42, which is a drive roller, and the pressing spring 71 is used. Second fixing device chassis
The oil applying roller 40 is always brought into a predetermined pressure contact state with the fixing roller 4a by rotating and urging the shaft of the drawing roller 42 counterclockwise in the drawing. The metaling blade 44 is held by a holder 73 which is swingable around a shaft 72, and the holder 73 is urged to rotate clockwise around the shaft 72 by a pressure spring 74 in the drawing. The oil applying roller 40 is kept in contact with the oil applying roller 40 at a constant pressure.

The oil on the oil application roller 40 whose amount is regulated by the metering blade 44 is the oil application roller 40.
Is transferred to the fixing roller 4a at the oil application portion which is the contact portion between the fixing roller 4a and the fixing roller 4a. The oil remaining on the application roller 40 is cleaned by the cleaning blade 3 before reaching the portion adjacent to the oil application roller 40 and the third scooping roller 41.
9, the oil pan 65 is attached together with the toner and the paper powder that are attached to the fixing roller 4a and transferred to the applying roller 40.
Removed outside. The removed oil is collected through a filter in an oil tank as described later, and circulates in the oil pan 65 for reuse.

The oil applying section will be described in more detail. The oil O drawn from the oil pan 65 by the first drawing roller 43 is
The amount of oil passing through is regulated to some extent by the gap between the and. Usually, a predetermined gap (0.1 mm to 0.3 mm) is provided between the first and second pumping rollers 43 and 42.
mm), and the amount of oil passing through is determined by this gap. Silicon oil O
Are pumped to the nip portion between the third pumping roller 41 and the second pumping roller 42. Here, the second scooping roller 42 has a groove with a depth of about 0.1 cut on the surface,
The oil O accumulated in the groove is transferred to the third scooping roller 41. The third scooping roller 41 is in contact with the coating roller 40 so as to slightly penetrate the coating roller 40, and the surface of the third scooping roller 41 has a surface roughness Ra3.2 so as not to damage the coating roller 40 whose surface layer is silicon rubber. I'm making it small. Here, the material of each pumping roller is metal. Next, the oil O transferred from the third scooping roller 41 is carried on the circumference of the coating roller 40 to the metering blade 44 which is a release agent coating means. Further, as described above, the oil applying roller 40 has a surface layer made of silicon rubber and an inside thereof made of foamed silicon sponge, and is fixed to a metal cored bar.

As described above, the metering blade 44 is rotatable about the rotation center shaft 72 of the holder 73.
The biasing spring 74 biases the coating roller 40 at a constant pressure. Therefore, the oil on the coating roller 40 passes through the portion in contact with the metering blade 44, so that the passing amount is regulated to a desired fixed amount, and an optimum oil film thickness is obtained. It is applied on the fixing roller 4a at the contact portion between the roller 40 and the fixing roller 4a.

The length of each roller is the same as that of the first pumping roller 4
The second scooping roller 42 is longer than the gap assurance flange portions at both ends of the third sheet 3, and the third scooping roller 41 is shorter than the second scooping roller 42. The third scooping roller 41 is shorter than the oil applying roller 40, and has a tapered end so as not to damage the surface rubber of the oil applying roller 40. The oil application roller 40 has a maximum sheet size of A3 with a width of 297 mm, and the variation of the sheet position is ± 2.
Considering mm, it is set to 301 mm. The metering blade 44 is longer than the oil application roller 40 so that the entire surface can be regulated.

The thermistor 48 is arranged in the oil pan 65, the oil temperature is detected by the controller 56 (FIG. 3), and the planar heater H is energized via the AC driver so as to be constant with respect to the set temperature. ing. Therefore, it is possible to secure the fixing property at the time of starting the machine and prevent the gloss change caused by the change in the oil application amount due to the oil viscosity.

Although FIG. 3 is a side view of the oil pan 65, the float 50 floats on the oil O in the oil pan 65. The float 50 is rotatably supported around a shaft 51 and moves up and down according to the liquid level of the oil O,
The flag 52 arranged on the opposite surface of the float 50 also rotates at the same time.

Therefore, when the oil O is consumed and the amount is reduced, the sensor 53 cannot detect the flag 52,
The signal is detected by the controller 56 of the main body, and the oil drawing pump 54 is operated. At that time, the oil pump 54 is installed in the lower part of the oil tank 55.
More oil O is pumped to the oil pan 65, and the sensor 5
3 detects the flag 52, the controller 56 stops the operation of the oil pumping pump 54, and the oil pan 6
Keep the liquid level of oil O in 5 constant.

Further, as described above, the cleaning blade 3
The oil containing the offset toner and the paper powder scraped off by 9 falls into the recovery pan 60. The collected oil is cleaned by the filter 61, returned to the oil tank 55, and circulated for use.

FIG. 4 is a diagram showing a drive system of the fixing device 4. The drive unit 9 on the printer body side is configured to output a drive by a drive motor unit including a motor unit 90 and a gear box 91, and a coupling 92 from an output shaft from the gear box 91 via an idle gear or a reduction gear train. Has been done.

The fixing device 4 is constructed so that it can be pulled out toward the front side of the printer main body for jam clearance and maintenance, and is connected to the printer main body side drive unit 9 via couplings 92 and 93. The drive transmitted from the couplings 92 and 93 is transmitted to the fixing roller 4a via a one-way gear 94 that locks in the drive direction and a reverse rotation prevention one-way gear 95 on the idle shaft. The pressure roller 4b is basically driven by the fixing roller 4a, and the driving force is transmitted so that the peripheral speed is slightly slower than that of the fixing roller 4a in case of slippage between the rollers. In order to prevent a conflict between the speeds of the two, a one-way gear 96 that locks in the driving direction is used, and when the fixing roller 4a is driven, the one-way gear 96 idles to absorb. The reverse rotation prevention one-way gear 95 is for preventing the fixing roller 4a from rotating in the direction opposite to the conveying direction by an external force of a user or the like. The one-way gear 94 is for reducing the load due to the acceleration of the drive unit by cutting off the drive when the user rotates the jam handling knob 97 during the jam handling.

(3) Image oil unevenness prevention control caused by oil pool D The image oil unevenness prevention control in this embodiment will be described. That is, a vibrating means for vibrating the metering blade 44 for regulating the amount of silicon oil with respect to the oil applying roller 40 is provided, and the oil unevenness on the applying roller 40 caused by the vibrating means is continuously fixed. The vibration generation timing of the vibration generating means is adjusted so as to come in between. That is, the metering blade 4
The oil pool accumulated in the vicinity of No. 4 is vibrated to the fixing roller 4a such as thick paper by adjusting the timing by the forced vibrating means so that it is located between the sheets and discharging it so that it is not transferred onto the sheet S. Even in the case of a sheet that gives a sheet, it is possible to prevent unevenness in the image without adding cost or space.

In the present embodiment, the vibration generating means is an intermittent drive force transmitted to the oil applying roller 40.
The driving force is interrupted by turning the motor off and on.

That is, the drive motor 90 (M) of the printer is turned on by the controller 56 (FIG. 3) of the printer body.
It is controlled to be turned on / off, and normally starts driving when a copy start signal is received, and stops when the sheet S is ejected outside the machine.

The controller 56 recognizes the paper thickness to be image-formed by the input from the user's operation unit.
The paper feed unit 3 may be configured to automatically recognize the paper thickness.

The timings of the above-mentioned paper feeding and image formation are also controlled by the controller 56 of the printer main body, and the time for the sheet S to reach the fixing nip portion N is calculated by the timer function. The sheet reaches 500m
100 seconds after turning off the drive motor 90 before sec
When the drive motor 90 is turned on after ec, the peripheral speed of the fixing roller 4a changes as shown in FIG.

At this time, the above-mentioned metering blade 44
The oil pool D accumulated at the position fluctuates similarly to the behavior when the leading end of the sheet S is caught in the fixing nip portion N. At this time, the oil sump D is discharged, and when the leading edge of the sheet S bites into the fixing nip portion N, the oil sump D has not grown yet, and the oil sump D is fixed even if the rotation fluctuation occurs as shown in FIG. Does not transfer to the roller 4a. Alternatively, even if the oil pool D occurs, it is so small that it does not pose a problem on the image.

The oil pool D generated by turning the drive motor OFF / ON is transferred to the fixing roller 4a, but does not appear on the image because it reaches the fixing nip portion N before the sheet S.

Further, in continuous sheet feeding in the continuous print mode, similarly, the oil pool D comes between the sheets (sheet interval), so that it is possible to prevent oil unevenness from occurring on the sheets. In that case, the waveform of FIG. 5 is repeated for each sheet.

In this embodiment, the peripheral speed of the fixing roller 4a is set to 20.
0 mm / s, the metering blade 4 which is the oil regulation part
The length L from 4 to the fixing nip portion N is 60 mm. The oil in the oil pool D on the fixing roller 4a that has passed through the fixing nip portion N and the oil in the oil pool D attached to the pressure roller 4b are respectively cleaned by the cleaning web 76.
-Wipe off by 77.

In this embodiment, the DC motor is used as the drive motor 90, but the stepping motor may be used for the control.

[Embodiment 2] (FIG. 6) In the present embodiment, the above-mentioned vibration generating means is an interruption of the driving force transmitted to the oil applying roller 40, and the interruption of the driving force is OFF / ON of the clutch in the drive train. Turn on.

That is, in this embodiment, as shown in FIG. 6, the electromagnetic clutch 100 is provided on the coupling shaft of the drive unit 9 on the printer body side, and the drive connection is established by the controller 56 (FIG. 3) of the printer body. Have control. The clutch 100 is turned off / on at the same timing as in the first embodiment.
Turn on. The position of the electromagnetic clutch may be provided on the fixing device 4 side as indicated by the chain double-dashed line 101.

The other structure of the apparatus is the same as that of the first embodiment, and therefore the repetitive description will be omitted.

[Embodiment 3] (FIG. 7) In this embodiment, as shown in FIG. 7, a swing arm 111 for giving an impact to the metering blade 44 is provided. The arm 111 is connected to the plunger of the solenoid 110, swings by hitting the pulsed current to the solenoid 110, and strikes the holder 73 of the metaling blade 44 to impact the metaling blade 44.

By turning on the solenoid 110 at the same timing as in the first embodiment, the metering blade 44 is turned on.
The part is shocked. The oil sump D is discharged at the moment when the shock is applied.

Instead of the solenoid 110, a means for giving vibration may be a cam, a motor with a weight that is out of balance, or a piezo or ultrasonic wave.

[Others] 1) Although the fixing roller has been described in the above embodiments, the fixing means may be a belt-shaped member such as a fixing belt, and the present invention is applicable. The fixing unit may be a pressure fixing member, and the present invention is applicable.

2) The image forming process means of the image forming apparatus is
It may be an appropriate image forming process means such as an electrophotographic system, an electrostatic recording system, a magnetic recording system or the like. Transfer method (indirect method)
Alternatively, the direct method may be used.

[0078]

As described above, according to the present invention, in an image forming apparatus such as a printer, a facsimile machine, a copying machine, or a multifunction machine having these functions, a release agent for applying a release agent to the surface of the fixing means. For those with coating means,
A vibration generating means for giving vibration to the regulating means for regulating the amount of the releasing agent material is provided, and the vibration is generated so that the unevenness of the releasing agent generated by the vibrating means comes between the sheets to be continuously fixed. By adjusting the vibration generation timing of the generating means, it is possible to prevent unevenness of an image even on a sheet such as a thick paper which vibrates the fixing means, without cost and space.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an image forming apparatus according to a first exemplary embodiment.

FIG. 2 is a schematic diagram of a main part of a fixing device.

FIG. 3 is a schematic diagram of the configuration of an oil pan

FIG. 4 is a schematic diagram of a fixing device drive system.

FIG. 5 is a diagram showing the peripheral speed fluctuation of the fixing roller.

FIG. 6 is a schematic diagram of a fixing device drive system according to a second exemplary embodiment.

FIG. 7 is a schematic diagram of a main part of a fixing device according to a third exemplary embodiment.

FIG. 8 is an explanatory view of the formation of an oil sump and its adverse effects in the conventional fixing device (No. 1).

FIG. 9 is an explanatory view (No. 2) of formation of an oil sump and its adverse effect in a conventional fixing device.

FIG. 10 is an explanatory view (No. 3) of formation of an oil sump and its adverse effect in a conventional fixing device.

FIG. 11 is a diagram showing the peripheral speed fluctuation of the fixing roller.

[Explanation of symbols]

1 ... Leader part, 2 ... Image forming part, 3 ... Paper feeding part 4
..Fixing device, 8..Conveying belt, 4a..Fusing roller, 4b..Pressure roller, 45a, 45b..Halogen heater, 46,47..Thermistor, 65..Oil pan, O..Silicone oil , 39 ··· Cleaning blade, 40 · · Oil application roller, 43 to 41 · · 1st
-Third pumping roller, 44 ... Metalling blade, 55 Oil tank 55, 90 Motor part, Gear box 91, 92 ... Coupling, 93 ... Coupling, 94 ... One way gear, 95 ... Reverse rotation prevention One-way gear, 96 ··· one-way gear, 97 · · jam handling knob, 100 · · electromagnetic clutch, 110 · · solenoid, 111 · · arm, S · · seat

Claims (4)

[Claims] 1. An image forming means for forming an image on a sheet, a fixing means for fixing the image by heating or pressurizing the sheet on which the image is formed, and a releasing agent for applying a releasing agent on the surface of the fixing means. Coating means, regulating means for regulating the amount of the release agent, vibration generating means for vibrating the regulating means, and unevenness of the releasing agent generated by the vibrating means between the sheets of the sheets which are continuously fixed. An image forming apparatus having a control means for adjusting the vibration generation timing of the vibration generation means so that the vibration generation means comes. 2. The release agent applying means is a rotating member which rotates adjacent to the fixing means, and the vibration generating means is an intermittent drive force transmitted to the rotating member. Claim 1
Image forming device. 3. The image forming apparatus according to claim 2, wherein the driving force is intermittently turned on / off by a motor. 4. Intermittent driving force is caused by the clutch O in the drive train.
The image forming apparatus according to claim 2, wherein the image forming apparatus is performed by FF / ON.