JPH1195592A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make coating with oil uniform and stable, for preventing the generation an image noise, with a long service life and a compact constitution, at a low cost by controlling a carrying means, never to make a releasing agent a saturated state in a releasing agent holding layer. SOLUTION: An unfixed toner image formed on a sheet 10 is pressed/heated/ fixed between a fixing roller 20 and a pressure roller 30. At this time, the surface of the fixing roller 20 is coated with oil 0, because there is a fear that an offset phenomenon occurs due to the fact that a part of retransferred to a next carried sheet 10. The oil 0 is guided to an oil coating means 40 by an oil carrying means 46 and the surface of the roller 20 is coated with the oil O through a coating roller 50 rotated with the rotation of the roller 20. In such a case, the oil quantity of an oil holding layer 56 is controlled so that the oil holding layer 56 always works under unsaturated conditions.

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 in an image forming apparatus such as an electrophotographic printer or a copying machine, and more particularly to a fixing device for fixing an image to a rotating body for heat and pressure fixing. The present invention relates to a fixing device provided with a mechanism for applying a release agent.

[0002]

2. Description of the Related Art Printers using an electrophotographic process,
2. Description of the Related Art An image forming apparatus such as a copying machine has a fixing device that fixes an unfixed toner image held on a sheet as a recording medium. As the fixing device, a pressure-heating fixing type is widely used.

Since the fixing device of this type has a configuration in which the surface holding the toner among the two surfaces of the sheet directly contacts the surface of the fixing roller, a part of the unfixed toner image on the sheet is transferred to the fixing roller side. Easy to be. For this reason, a so-called offset phenomenon occurs in which the toner fused to the fixing roller is transferred again to the rear end of the sheet to stain the sheet, or is transferred again to the next conveyed sheet to stain the sheet. There is a disadvantage that it is easy.

Therefore, a fixing device using a pressure heating fixing method, particularly a fixing device for a color, generally has a mechanism for applying a release agent to the fixing roller in order to smoothly release the toner from the fixing roller. ing. As the release agent, a silicone release agent (hereinafter, also simply referred to as “oil”) is used.

In such an oil applying mechanism, when the sheet passes through the sheet, that is, when the sheet passes, the sheet or the like carries away the oil on the surface of the fixing roller, so that the oil on the surface of the fixing roller must be replenished. The oil application mechanism needs to be provided with a mechanism for replenishing oil.

As such an oil replenishing mechanism, an excessive amount of oil is applied to the surface of the fixing roller, and excess oil is collected by an oil collecting mechanism and reused (for example, Japanese Patent Application Laid-Open No. 5-265346). Japanese Patent Application Laid-Open No. H10-260, or an apparatus in which a small amount of oil is exuded from a roller in which a predetermined amount of oil is stored in advance, and the whole is replaced when a predetermined amount of oil is used. 2-23382) and the like.

[0007]

However, in the former method, there is a disadvantage that more oil than necessary is taken by the sheet, and an oil recovery mechanism is required, which is disadvantageous in cost.

In the latter method, the amount of oil retained is limited, and if an attempt is made to retain a large amount of oil in order to extend the life, the entire apparatus becomes large. In order to hold a large amount of oil, for example, the diameter of the application roller must be large. However, if a large-diameter application roller is used, the device itself becomes large.

As shown in FIG. 10, when the roller in which the oil is stored is set, the amount of oil seeping is large, but the amount of oil seeping gradually decreases as the number of sheets passed increases. A situation has arisen in which the amount of oil seepage differs depending on the amount of oil retained. For this reason, the amount of oil seepage is not stable, and in some cases, oil may leak from the fixing roller, causing a problem such as an oil streak, an offset, and image noise.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems associated with the prior art described above, and is a fixing device which has a long service life, is compact in construction, and is excellent in cost. It is another object of the present invention to provide a fixing device that can be stable and can prevent the occurrence of image noise.

[0011]

The object of the present invention is achieved by the following means.

(1) A pair of rotating bodies for heat and pressure fixing an unfixed toner image held on a sheet, coating means for contacting one of the rotating bodies and applying a release agent, Transport means for transporting the release agent to the application means in a timely manner,
The coating unit includes at least one hollow roller, and has a release agent holding layer for temporarily holding the release agent on the outer peripheral surface and transferring the release agent to the rotating body. In the fixing device configured to supply the release agent to the agent holding layer by the transport unit, the transport unit is controlled so that the release agent is not always saturated in the release agent holding layer. A fixing device characterized by the above-mentioned.

(2) The coating means has a first roller rotatable in contact with the rotating body, and a release agent holding layer on the outer peripheral surface, and the release agent is supplied inside from the transport means. Second
And a coating layer for transferring the release agent impregnated in the release agent holding layer to the rotating body by the outer peripheral surface of the first roller. apparatus.

(3) The coating means temporarily holds the hollow core metal that allows the release agent supplied from the transport means to seep into the surface layer, and the extruded release agent. A releasing agent holding layer for transferring the releasing agent to the rotating body.

(4) A pair of rotating members for fixing the unfixed toner image held on the sheet by heat and pressure, a coating means for applying a release agent in contact with one of the rotating members, And a control unit for controlling the supply of the release agent to the application unit in a timely manner. The control unit is configured to release the release agent based on information on the number of sheets passing through the rotating body. A fixing device characterized in that a supply amount and / or a timing of conveying a mold agent are controlled.

(5) The fixing device, wherein the control means controls the supply amount and / or the timing of transport of the release agent based on the rotation speed information of the rotating body.

(6) The fixing device, wherein the control means controls the supply amount and / or the timing of transport of the release agent based on the information on the paper passing mode.

(7) The fixing device, wherein the control means controls the supply amount and / or the timing of conveyance of the release agent based on information on the size of the sheet.

(8) The fixing device, wherein the control means controls the supply amount and / or the timing of transport of the release agent based on information on the number of rotations of a roller constituting the coating means.

(9) The fixing device, wherein the control means controls the supply amount and / or the timing of transport of the release agent based on the weight of a roller constituting the coating means.

(10) The control means includes information on the number of sheets passing through the rotating body, information on the sheet passing mode, information on the size of the sheet, information on the number of rotations of the rollers constituting the application means, or information on the weight. A supply amount of the release agent and / or a timing of transporting the release agent based on a plurality of pieces of information selected from the group consisting of:

(11) The fixing device, wherein the control means variably controls a supply amount and / or a conveyance timing of the releasing agent.

(12) A pair of rotating members for fixing the unfixed toner image held on the sheet by heat and pressure, and an application means for applying a release agent in contact with one of the rotating members.
A conveying unit for appropriately conveying the release agent to the application unit, a control unit for controlling the supply of the release agent, and a forcible switch for forcibly supplying the release agent, and the forcible switch is operated. Then, the release agent is supplied in preference to the control by the control means.

(13) The fixing device according to the present invention, wherein the control means resets a counter for determining a supply amount of the release agent and / or a timing of transport when the forcible switch is operated.

(14) A pair of rotating members for fixing the unfixed toner image held on the sheet by heat and pressure, and an application means for applying a release agent in contact with one of the rotating members.
A transport unit for appropriately transporting the release agent to the application unit, and a control unit for controlling the supply of the release agent, wherein the control unit supplies the release agent when the application unit is replaced. And / or resetting a counter for the timing of conveyance.

(15) A pair of rotating members for fixing the unfixed toner image held on the sheet by heat and pressure, and an application means for applying a release agent in contact with one of the rotating members.
The apparatus has a transporting unit for appropriately transporting the release agent to the application unit, and a control unit for controlling the supply of the release agent, wherein the control unit supplies a predetermined amount of the release agent at the supply timing of the release agent. A fixing device wherein an image forming operation is prohibited when the image forming operation cannot be performed.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram illustrating a fixing device according to the first embodiment, FIG. 2 is a schematic configuration diagram illustrating an oil conveying unit according to the first embodiment, and FIG. 3 is a flowchart illustrating an oil supply operation according to the first embodiment. FIG. 4 is a graph showing the relationship between the oil content and the amount of applied oil according to the first embodiment, and FIG. 5 is a graph showing the oil supply state according to the first embodiment.

In FIG. 1, a fixing device 100 is of a pressure heat fixing type, and is used by being incorporated in an image forming apparatus such as a printer having a known electrophotographic image forming means.

The fixing device 100 is provided so as to be rotatably driven in the direction of the arrow a, and is pressed against the fixing roller 20 in a pair with the fixing roller 20. The fixing device 20 is driven by the rotation of the fixing roller 20. Rotating pressure roller 30
And heaters 21 and 31 for heating the respective rollers 20 and 30
And at least one of the rollers (the fixing roller 2 in the illustrated example).
0) has an oil applying means 40 for applying oil O as a release agent for preventing offset, and a conveying means 46 for conveying the oil O to the applying means 40 in a timely manner.

The fixing roller 20 and the pressure roller 30
Corresponds to a rotating body R for fixing the toner 11 held on the sheet 10 with heat and pressure. Silicon oil is used as the oil O. Also, reference numeral “4” in FIG.
Reference numeral 1 "denotes a cleaning roller having a surface provided with a fiber layer.

The fixing roller 20 is a hollow metal pipe 2
2 is coated with a fluororesin to form a release layer 23 having good releasability and heat resistance to the toner. On the center axis of the fixing roller 20, a tubular heater such as a halogen lamp 21 is arranged.
The fixing roller 20 has a driving gear (not shown) fixed to one end thereof, and is driven to rotate by a driving source (not shown) such as a motor connected to the driving gear.

The pressure roller 30 is a hollow metal pipe 3
2, a silicon rubber layer 33 is provided on the outer periphery, and the halogen lamp 31 is arranged on the center axis thereof. The silicone rubber layer 33 is a rubber layer having releasability from which the sheet 10 is easily separated from the surface and having heat resistance. The pressure roller 30 is fixed to the fixing roller 2 by a spring material (not shown).
It is pressed in the direction toward zero. The fixing roller 2
In the case where the toner can be sufficiently fixed only by the halogen lamp 21 built in the printer 0, the halogen lamp 31 on the pressure roller 30 side may be omitted.

Here, in fixing the toner, first, a predetermined voltage is applied to the halogen lamps 21 and 31, and the radiant heat generated from the halogen lamps 21 and 31 causes the outer wall temperature of the fixing roller 20 and the pressure roller 30 to rise. Is heated to a temperature suitable for fixing.

Sheet 10 Holding Unfixed Toner 11
1 is conveyed from the right as indicated by an arrow b in FIG. 1 and sent toward a nip portion 12 which is a contact portion between the fixing roller 20 and the pressure roller 30.

The sheet 10 is conveyed while being nipped by the nip 12 while the heat from the fixing roller 20, the heat from the pressure roller 30, and the pressure applied from the pressure roller 30 are applied.

As a result, the unfixed toner 11 is
0 is fixed. The toner 11 is held on the side of the sheet 10 that contacts the fixing roller 20.
The sheet 10 that has passed through the nip 12 is naturally separated from the fixing roller 20 by a curvature according to the strength of the sheet 10 itself,
In FIG. 1, it is conveyed to the left.

The sheet 10 is conveyed by a discharge roller (not shown) and discharged onto a discharge tray (not shown).

The oil applying means 40 extends along the axial direction of the fixing roller 20 and is driven and rotated by the fixing roller 20 to remove the oil O on the outer peripheral surface of the fixing roller 2.
The application roller 50 is formed of a hollow roller that extends along the axial direction of the application roller 50 and supplies oil O to the application roller 50.

This will be described in more detail. This application roller 50
It is constituted by a hollow roller having a silicon rubber layer 52 provided on the outer periphery of a metal pipe 51, and is supported so as to be able to rotate freely as the fixing roller 20 rotates. This coating roller 5
0 is the oil application means 40 in the present embodiment.
This is a portion that constitutes a coating layer that transfers the oil O to the rotating body R.

On the other hand, as shown in FIGS. 1 and 2, the supply roller 53 is formed of a hollow roller in which an outer periphery of a cylindrical metal core 55 having a plurality of through holes 54 and an oil holding layer 56 is covered. It is supported so as to be driven to rotate with the rotation of the application roller 50. In addition, on the central axis of the supply roller 53, a supply nozzle 43, which is a part of a conveying unit 46 described later, is arranged in a non-rotating state.

In the supply roller 53, the through-hole 54 is a means for allowing oil O supplied from the conveying means 46 to seep into the surface layer. In this case, the through-hole 54 communicates the inner and outer surfaces of the cored bar 55. As described above, the holes are formed as small holes opened at substantially equal intervals. The oil holding layer 56
Is a portion for temporarily holding oil O to be supplied to the application roller 50, and is formed of, for example, a porous material such as sponge, paper material, felt, silicon rubber, etc. which can impregnate the oil therein. ing.

As shown in FIG. 2, the transport means 46
A plurality of discharge holes 42 provided in the supply roller 53 are provided.
A supply nozzle 43 for supplying oil O into the supply roller 53 from above, a sealed oil tank 45 storing the oil O, an oil pump 60 for feeding the oil O in the oil tank 45 to the supply nozzle 43, A tube 6 communicating with the oil tank 45, the oil pump 60, etc.
1 and 62 and control means 70 for controlling the motor M of the oil pump 60.

The supply nozzle 43 has a pipe 65 made of stainless steel or the like. A supply hole 66 is opened at one end of the pipe 65, the tube 62 communicates with the supply hole 66, and the other end of the pipe 65 is plugged. It is closed by a member 67 and the like, and a plurality of discharge holes 42 are opened in an intermediate portion.

The discharge holes 42 are configured such that the amount of oil discharged from each of them is uniform. That is, a plurality of through-holes 68 are formed at a predetermined pitch in the pipe 65, and tube pipes 69 made of stainless steel or the like having substantially the same hole diameter are inserted into these through-holes 68. The opening cross-sectional areas of the oil O discharge holes 42 are made substantially the same.

In this case, since the diameters of the through hole 68 and the tube pipe 69 are substantially the same along the longitudinal direction, it is necessary to increase the diameter of the pipe 65 even if the nozzle length is increased. Therefore, it is possible to avoid an increase in the size of the oil applying means 40.

In addition, since the diameters of the holes are substantially the same, the formation of the discharge holes 42 does not become complicated, the increase in manufacturing cost can be suppressed, and the fixing device 100 can be made compact and cost can be reduced.

The oil tank 45 is of a closed type.
This is because a large amount of oil O can be held without spilling even if vibration is applied or tilted to the oil tank 45.

In particular, in the present embodiment, with respect to the holding of the oil O, the conveying means 46 is controlled so that the oil O is not always saturated in the oil holding layer 56.

Oil O impregnated in oil holding layer 56
Is transferred from the supply roller 53 to the surface of the application roller 50. If this state is analyzed in more detail, the supply roller 53 and the application roller 50 come into contact with each other with a predetermined force. Supply roller 53 having
Is driven to rotate with the rotation of the application roller 50.

During this rotation, the oil O is quickly discharged from the oil holding layer 56 by contact, and
Will be transferred to the surface, but when rotation stops,
The oil accumulates in the lower part of the oil holding layer 56 under the action of gravity.

In this case, if the oil content of the oil holding layer 56 is higher than necessary, the oil holding layer 56 falls down and falls on the application roller 50. This causes oil streaks, offsets, and the like when restarted. On the other hand, if the oil content of the oil holding layer 56 is extremely low, the oil does not flow to the application roller 50, and the function of removing and releasing the toner becomes insufficient.

For this reason, in the oil holding layer 56 according to the present embodiment, the oil holding layer 56 is not always saturated. More specifically, the control unit 70 controls the amount of oil supplied to the oil holding layer 56 and the timing at which the oil is conveyed, so that the oil amount in the oil holding layer 56 is not always saturated.

In this case, the control of the amount of oil in the oil holding layer 56 does not necessarily need to control both the amount of oil supplied and the timing at which the oil is conveyed. In some cases, only one of them may be controlled.

Here, the relationship between the oil content of the oil holding layer 56 and the amount of applied oil can be represented by a curve as shown in FIG. 4 when the oil content of the oil O is expressed by volume percentage.

On the premise of such a relationship, an experiment was conducted in which the release state was checked for each predetermined number of sheets passed to determine the quality.

In the experiment, the oil content of the oil O impregnated in the oil holding layer 56 is expressed as a volume percentage, and when each of the ten sheets is passed through the rotating body R at intervals of 10 minutes under each oil content. The results are shown in Table 1 below, in which the presence / absence of stains and oil streaks on the sheet due to retransfer and the occurrence of unevenness in image gloss are visually observed.

[0057]

[Table 1]

In this experiment, the oil content must be 20% or more in order to eliminate the stain on the sheet due to the retransfer, and the oil content must be 80% in order to eliminate the generation of oil streaks.
It turns out that it must be: Further, it can be seen that the oil content is preferably 30% or more in order to prevent the occurrence of image gloss unevenness which is a problem in color copying and the like. However, the image gloss unevenness that occurred when the oil content was 30% was a practically acceptable level.

As is clear from these results, the oil retaining layer 56 can be made practical to some extent by setting the volume percentage in a range of 20% to 80%, and more effective. In order to achieve this, a value between 40% and 60% is preferable. That is, if such a range is selected, uniformity, stabilization, and long life of the oil application can be achieved, and the oil holding layer 56 can always be in a good oil state.

Therefore, in the present embodiment, the oil content of oil O impregnated in oil holding layer 56 is 4% by volume percentage.
The amount of oil O supplied to the inside of the supply roller 53 and the timing of its conveyance are controlled so as to be between 0% and 60%. This control is performed by controlling the motor M of the oil pump 60 by the control means 70.

As the control means 70, a CPU or the like incorporated in a main body of a copying machine or the like may be used.
As shown in FIG. 2, the motor M of the oil pump 60 is connected to the motor M, and a change in the torque applied to the motor M is detected by a torque sensor (not shown) or the like. It is determined that the oil has been conveyed so as to have a predetermined oil content. If it exceeds 10%, it is determined that an abnormal situation has occurred such as an excessive supply of oil or a shortage of oil in the tank. To be processed.

However, the initial oil content of the oil retaining layer 56 is set in the above range by a method such as measuring the weight of the supply roller 53 in a state where the oil retaining layer 56 is impregnated with the oil O. .

In this manner, the operation of the oil holding layer 56 is started from a state where the oil content of the oil O is 40% to 60% from the beginning. When the number of sheets reaches a predetermined number, a predetermined amount of oil O is supplied at a predetermined timing.

As a result, in the oil supply state of the first embodiment, as shown in FIG. 5, a predetermined amount of oil O is intermittently supplied every predetermined number of sheets passed, and a predetermined oil content is always maintained.
The oil O in the oil holding layer 56 is controlled so as not to be saturated.

Here, in the first embodiment, the control means 7
Although the number of sheets passed is used as a control factor of 0, this is usually performed by counting the number of sheets passed. This is because it is easy to process.

According to experiments, the amount of oil required for one sheet 10 is 10 mg to 15 mg. According to this, when the number of sheets passed is 1000 sheets, 10 g
An oil application amount of 15 g is required.

Accordingly, if the oil content of the oil holding layer 56 is 40% to 60%, the amount of oil and the supply timing can be easily controlled by using the number of sheets passed as a control factor. 70.

However, the present invention is not limited to only such control factors, and other control factors can be used. For example, the number of sheets passed through the control factor used here is the number of sheets that have passed through the fixing roller 20 and the application roller 50. Therefore, the number of rotations of the fixing roller 20 and the rotation of the application roller 50 are not corrected. A number could be used as a control factor.

Further, information on the size of the sheet 10 can be used as a control factor. FIG. 6 shows a change in the amount of applied oil when a small-sized sheet 10 such as B5 size is used and when a large-sized sheet 10 such as A4 size is used. Here, as the number of passed sheets increases, the amount of applied oil shows a decreasing tendency, which shows that the tendency is more remarkable when the large-sized sheet 10 is used. , Means that the size of the sheet 10 can be set as one control factor though it depends on the number of sheets passed. Here, the number of rotations of the fixing roller 20 and the number of rotations of the application roller 50 are described in parentheses in addition to the number of papers passed along the horizontal axis. This means that the same result is obtained even if the number of rotations is changed to 50.

It is needless to say that the fixing roller 2
The number of rotations of the application roller 50 may be set to 0 or the number of rotations of the pressure roller 30 or the supply roller 53.

The information on the paper passing mode can be used as a control factor. FIG. 7 shows changes in the amount of oil applied when paper is intermittently passed and when paper is continuously passed. Again, as the number of passed papers increases, the amount of oil applied tends to decrease, and this tendency is apparently more pronounced when paper is intermittently passed. The paper mode also means that it can be a control factor, though via the number of sheets passed. Here, in addition to the number of sheets passed on the horizontal axis, the fixing roller 20 is written in parentheses.
The number of rotations and the number of rotations of the application roller 50 are also described.
This also means that the same result is obtained even if the number of sheets passed is replaced with the number of rotations of the fixing roller 20 or the number of rotations of the application roller 50.

The paper passing mode does not only mean intermittent paper passing or continuous paper passing but also includes a single-sided printing mode and a double-sided printing mode. In particular, in the double-sided printing mode, the sheet 10 that has passed once passes again, but when the sheet 10 passes this second time, the amount of oil used is reduced. For this reason, it is significant to use the case of the one-sided printing mode or the two-sided printing mode as the control factor.

The weight of the application roller 50 and the supply roller 53 can be used as a control factor. This is because the weight of these rollers changes depending on the amount of oil applied.

Further, information on the number of sheets passing through such a fixing device, information on the sheet passing mode, information on the size of the sheet, information on the number of rotations of the application means constituted by the application roller, the weight of the application roller, etc. A plurality of pieces of information selected from the above may be used as the control factors.

Next, the operation of the above embodiment will be described.
In a copier or the like, the unfixed toner image formed on the sheet 10 is fixed by being pressed and heated between the fixing roller 20 and the pressure roller 30, and a part of the unfixed toner is fixed. There is a possibility that the toner adheres to the surface of the roller 20 and is transferred again to the sheet 10 to be conveyed again, causing an offset phenomenon.
Oil O is applied to the surface of the zero.

The oil O is guided by the oil conveying means 46 to the oil applying means 40, and passes through a path of being applied to the surface of the fixing roller 20 via the applying roller 50 which is driven and rotated by the fixing roller 20.

This will be described in more detail. The oil O is sucked up from the oil tank 45 by driving the pump 60 of the oil conveying means 46, is conveyed to the supply nozzle 43 provided in the supply roller 53 through the tubes 61 and 62, and is And is discharged as droplets.

The droplets of the oil O in the supply nozzle 43 are supplied in a point-like manner, are absorbed by the oil holding layer 56, and spread in a plane. However, each discharge hole 42 of the supply nozzle 43 has a uniform diameter. In addition, since they are provided at intervals of a predetermined pitch, the amount of oil discharged from each discharge hole 42 is uniform. In addition, since the supply roller 53 is driven and rotated by the application roller 50, the oil O
Is applied over the entire area of the oil holding layer 56 and further squeezed out to some extent by the pressing of the application roller 50, expanded and transferred to the application roller 50. The coating is applied so as to be uniformly distributed over the entire surface of the roller 20.

As a result, the toner adhering to the surface of the fixing roller 20 is removed by the action of the oil O and the cleaning roller 41.

However, for example, when the apparatus is stopped, the oil O impregnated in the oil holding layer 56 collects below the oil holding layer 56 under the influence of gravity, thereby causing the above-described offset at the time of restart. Because there is a fear,
The amount of oil in the oil holding layer 56 is controlled and the oil holding layer 5 is controlled.
6 always operates under unsaturated conditions. That is, in the present embodiment, the sheet 1 that has passed the rotating body R
The supply amount and supply timing of the oil O are controlled based on the number information of 0.

FIG. 3 is a flowchart showing the oil supply operation of this embodiment. In the present embodiment, the number of sheets 10 is counted by a sheet passing counter (not shown) provided at a predetermined position (step 1), and it is determined whether the sheet passing counter has reached a set value (step 1). Step 2).

When the number of passed sheets does not reach the set value,
Returning to step 1, when the number of passed sheets reaches the set value, as shown in FIGS. 4 and 5, the oil in the oil holding layer 56, which initially had an oil content of, for example, 60%, gradually decreases. For example, when it reaches about 40%, it becomes necessary to replenish.

Accordingly, when the motor M is turned on (step 3) and the pump 60 operates, the oil O is pumped to the oil holding layer 56. That is, the supply amount of the oil O is controlled by adjusting the rotation speed of the motor M, and the supply timing, which is the rotation start timing of the motor M, is controlled by the sheet passing counter.

At the time of pumping the oil, a torque is applied to the motor M. If this torque fluctuation is 10% or less (step 4), a predetermined amount of oil O is normally supplied,
Assuming that the oil content of the oil holding layer 56 has reached 60%, the motor M is stopped and the sheet passing counter is reset in step 5 (step 5).

However, if the fluctuation of the torque of the motor M does not become less than 10% in spite of the state in which the oil is to be supplied, it is determined that an abnormal situation has occurred and the information for prohibiting the image forming operation is notified. (Step 6), and the oil supply operation is stopped.

The case where the fluctuation of the torque is not less than 10% is a case where a predetermined amount of the oil O cannot be supplied at the time of supplying the oil O. For example, the supply roller 53 is clogged for some reason. In this case, the oil O cannot be pumped and the torque of the motor M increases, or the oil O in the oil tank becomes empty and the torque of the motor M becomes extremely small.

In such a case, the operation is stopped along with the display of "image forming operation prohibited" automatically by the control means 70. In some cases, the oil O is forcibly supplied. Even if the operation of the control means 70 is ignored by turning on the forcible switch 72, or if the counter for the supply amount of oil O and the timing of conveyance is reset by turning on the forcible switch 72, good.

When the supply amount and supply timing of the oil O are controlled in this way, the oil content of the oil O in the oil holding layer 56 periodically fluctuates between 40% and 60%. If the width of the fluctuation is within the range, the oil applying means 40 can be more effective.

Further, clogging of the supply roller 53,
When the oil O in the oil tank becomes empty, there is a case where these are replaced. However, at the time of such replacement of the applying means, the counter for controlling the supply amount and timing of the oil O is reset. Is also good.

The present invention is not limited to the above-described embodiment, but can be variously modified and used within the scope of the claims.

For example, the control means may be configured as shown in FIGS.
It can be incorporated in a device as shown in FIG. In FIGS. 8, 9 and 10, members common to those shown in FIGS. 1 and 2 are denoted by the same reference numerals.

FIG. 8 is a schematic configuration diagram showing a second embodiment of the present invention. In the first embodiment, since the oil content of the oil holding layer 56 is set to a predetermined value, oil does not leak or drip from the oil holding layer 56, and the oil pan 58 needs to be provided below the supply roller 53. Therefore, there is an advantage that the device configuration can be simplified.

However, for the sake of safety, as shown in FIG. 8, an oil pan 58 is provided below the supply roller 53, and an oil application roller is provided to remove oil not applied to the fixing roller 20. An oil regulating blade 57 having a length substantially equal to the axial length of 50 may be provided, and the oil O removed by the oil regulating blade 57 may be received by the oil pan 58.

FIG. 9 is a schematic configuration diagram showing a third embodiment of the present invention. In the first embodiment, since the oil applying unit 40 uses the application roller 50 as the application layer of the supply roller 53, the oil application unit 40 includes two rollers. However, the present invention necessarily uses two rollers. There is no need, and only one may be used.

In the third embodiment, the supply roller 53 comes into direct contact with the rotating body R, and the application roller 50 is not used. Even in this case, since the oil content of the oil holding layer 56 is controlled to a predetermined value, the oil can be transferred from the oil holding layer 56 to the rotating body R without causing an offset or the like. Can also be simplified.

FIG. 10 is a schematic configuration diagram showing a fourth embodiment of the present invention. In the first to third embodiments, the oil holding layer 56 is provided on the outer peripheral surface of the roller. However, the present invention does not necessarily require the use of the roller.

In the coating means of this embodiment, an oil holding layer 56 is provided so as to be in contact with a coating roller 50 which is pressed against the fixing roller 20, and oil O is dropped from the supply nozzle 43 to the oil holding layer 56 to impregnate it. It is supposed to be. The oil holding layer 56 is formed of a porous material such as sponge and felt.

[0098]

As described above, the present invention has the following effects.

According to the first aspect of the present invention, since the release agent is not always saturated in the release agent holding layer, the service life of the release agent is extended, and the entire apparatus is compact. Thus, the fixing device is excellent in cost. Also,
The application of oil can be made uniform and stable, so that the occurrence of image noise can be prevented.

According to the second aspect of the present invention, since the applying means is constituted by two rollers, one of the rollers is provided with a release agent holding layer, and the other roller is used as an oil applying layer. Oil can be more uniformly and stably applied.

According to a third aspect of the present invention, the coating means is provided with a release agent holding layer on a surface layer of a hollow core metal from which the release agent is exuded. Is transferred, the management of the release agent in the release agent holding layer is simplified, and the workability of oil application is improved.

According to the fourth aspect of the present invention, since the supply amount and / or the timing of transport of the release agent is controlled using the number of sheets passed, the number of rotations of the rotating body and the like as control factors, the control is simplified. .

According to the eleventh aspect of the present invention, since the supply amount of the release agent and / or the timing of transporting the release agent are variably controlled, the release agent in the release agent holding layer can be managed. It will be more accurate.

According to the twelfth aspect of the present invention, since the forcible switch for forcibly supplying the release agent is provided prior to the control by the control means, even if an abnormal situation occurs, it can be easily dealt with. .

According to the thirteenth and fourteenth aspects of the present invention, when the forcible switch is actuated or the coating means is replaced, the counter for determining the supply amount of the release agent and / or the timing of transport is reset. Therefore, there is no malfunction in the processing after the occurrence of the abnormal situation, and the operability and safety are high.

According to the fifteenth aspect, the image forming operation is prohibited when a predetermined amount of the release agent cannot be supplied at the time of supply of the release agent. It is economical, has no malfunction in processing after occurrence of an abnormal situation, and has high safety.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing Embodiment 1 of the present invention.

FIG. 2 is a schematic configuration diagram illustrating an oil conveying unit according to the first embodiment.

FIG. 3 is a flowchart showing an oil supply operation of the first embodiment.

FIG. 4 is a graph showing a relationship between an oil content and an oil application amount according to the first embodiment.

FIG. 5 is a graph showing an oil supply state according to the first embodiment.

FIG. 6 is a graph showing the relationship between the number of sheets passed and the amount of applied oil when the size of a sheet changes.

FIG. 7 is a graph showing the relationship between the number of sheets passed and the amount of applied oil when the sheet passing mode changes.

FIG. 8 is a schematic configuration diagram showing a second embodiment of the present invention.

FIG. 9 is a schematic configuration diagram showing a third embodiment of the present invention.

FIG. 10 is a schematic configuration diagram showing a fourth embodiment of the present invention.

FIG. 11 is a graph showing the relationship between the number of sheets passed and the amount of applied oil in the conventional apparatus.

[Explanation of symbols]

 Reference Signs List 10: sheet, 11: toner, 40: coating means, 46: transport means, 50: coating roller (first roller, coating layer), 53: supply roller (second roller), 56: release agent holding layer Reference numeral 52: hollow core metal; 70, control means; 72, forced switch; O, release agent (oil); R, rotating body.

Claims (15)

[Claims] 1. A pair of rotating members for fixing an unfixed toner image held on a sheet by heat and pressure, coating means for contacting one of the rotating members and applying a release agent, and the coating device Means for transporting the release agent in a timely manner, wherein the application means is constituted by at least one hollow roller, temporarily holds the release agent on the outer peripheral surface, and transfers the release agent to the rotating body. In a fixing device having a release agent holding layer for transferring, and configured to supply the release agent to the release agent holding layer by the transport unit, the release agent is disposed in the release agent holding layer. A fixing device characterized in that the conveying means is controlled so as not to be always saturated. 2. The coating unit has a first roller rotatable in contact with the rotating body, and a release agent holding layer on an outer peripheral surface,
A second roller to which a release agent is supplied from the transport means, and wherein the release layer impregnated in the release agent holding layer transfers the release agent to a rotating body. 2. The roller according to claim 1, wherein the first roller is formed by an outer peripheral surface.
3. The fixing device according to claim 1. 3. The coating means is for temporarily holding a hollow core metal for allowing the release agent supplied from the transport means to seep into the surface layer, and for temporarily holding the extruded release agent. And a coating layer for transferring the release agent to the rotating body.
3. The fixing device according to claim 1. 4. A pair of rotating bodies for heat and pressure fixing an unfixed toner image held on a sheet, coating means for contacting one of the rotating bodies with a releasing agent, and applying the releasing agent. Means for transporting the release agent in a timely manner, and control means for controlling the supply of the release agent, wherein the control means releases the mold based on information on the number of sheets passing through the rotating body. A fixing device characterized in that the supply amount and / or the timing of transport of the agent are controlled. 5. The apparatus according to claim 4, wherein the control means controls the supply amount and / or the timing of transport of the release agent based on the rotation speed information of the rotating body. Fixing device. 6. The fixing device according to claim 4, wherein the control unit controls the supply amount and / or the timing of transporting the release agent based on the information on the paper passing mode. . 7. The fixing device according to claim 4, wherein the control unit controls a supply amount and / or a timing of conveying the release agent based on information on a sheet size. . 8. The method according to claim 4, wherein said control means controls the supply amount and / or the timing of transport of the release agent based on information on the number of revolutions of a roller constituting said coating means. The fixing device as described in the above. 9. The fixing device according to claim 4, wherein the control unit controls a supply amount and / or a timing of conveying the release agent based on a weight of a roller constituting the application unit. apparatus. 10. The information processing apparatus according to claim 1, wherein the control means selects information on the number of sheets passing through the rotating body, information on a sheet passing mode, information on a sheet size, information on the number of rotations of a roller constituting the application means, or weight. 5. The fixing device according to claim 4, wherein the supply amount and / or the timing of conveying the release agent are controlled based on a plurality of pieces of selected information. 11. The fixing device according to claim 4, wherein the control unit variably controls a supply amount of the release agent and / or a conveyance timing. 12. A pair of rotating members for fixing an unfixed toner image held on a sheet by heat and pressure, a coating means for contacting one of the rotating members with a releasing agent, and a coating device. The conveying means for appropriately conveying the release agent to the means, a control means for controlling the supply of the release agent, and a forcible switch for forcibly supplying the release agent, when the forcible switch is operated, A fixing device, wherein a release agent is supplied prior to control by the control unit. 13. The apparatus according to claim 12, wherein the control means resets a counter for determining a supply amount of the release agent and / or a timing of transport when the forcible switch is operated. The fixing device as described in the above. 14. A pair of rotating bodies for heat and pressure fixing an unfixed toner image held on a sheet, coating means for contacting one of the rotating bodies with a releasing agent, and applying the releasing agent. Means for transporting the release agent in a timely manner, and control means for controlling the supply of the release agent, wherein the control means supplies the release agent and / or supplies the release agent when the application means is replaced. Alternatively, a fixing device for resetting a counter for the timing of conveyance is provided. 15. A pair of rotating bodies for fixing an unfixed toner image held on a sheet with heat and pressure, coating means for applying a release agent in contact with one of the rotating bodies, and the coating method. Means for transporting the release agent in a timely manner, and control means for controlling the supply of the release agent, wherein the control means cannot supply a predetermined amount of the release agent at the supply timing of the release agent. A fixing device for prohibiting an image forming operation in a case where the fixing operation is performed.