JPH11161076A - Releasing agent coating control method for fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a releasing agent coating control method for a fixing device capable of fixing a high-quality image on a recording medium. SOLUTION: In the fixing device, there is possibility that oil is concentrated at a low end because an oil roller 60 is held in fixed posture when specified time or more elapses after performing fixing processing or when the roller 60 is exchanged. By turning the roller 60 for a specified time in a state where the roller 60 abuts on a heating roller 56 before performing the fixing processing, the thickness of an oil film formed on the roller 56 is made uniform. Since the fixing processing is performed by the roller 56, the fixed image on the recording medium has high quality without irregular gloss.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the application of a release agent to a fixing device provided in an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, image forming apparatuses such as a color printer and a color copy using an electrophotographic technique have been used. These image forming apparatuses are provided with a fixing device including a heating roller and a pressure roller in order to fix an unfixed image formed by the image forming unit on a recording medium. In this fixing device, a release film (for example, an oil film) is formed on the surface of the heating roller in order to prevent the toner from being peeled from the recording medium to the heating roller. That is, the oil is supplied by bringing the oil roller into contact with the heating roller to form an oil film on the outer peripheral surface of the heating roller, thereby preventing separation of the toner from the recording medium.

[0003] This oil roller is composed of an oil holding layer formed of a foam or the like impregnated with oil, and an oil control layer that allows oil to permeate the outer peripheral surface of the roller by gravity, centrifugal force, thermal expansion, or the like. ing.

[0004]

In such a fixing device, when the oil roller is kept in contact with the heating roller, the oil is locally accumulated in the contact portion between the oil roller and the heating roller. Become. If an unfixed image is fixed on the recording medium by rotating the heating roller in this state, the oil locally concentrates and adheres to the recording medium, and the recording medium becomes uneven in gloss. .

Therefore, when it is not necessary to supply oil, the oil roller is separated from the heating roller.

However, when the image forming apparatus has not been used for a long time, the lower end (6
Oil concentrates in the direction of time). Therefore, immediately after replacing the oil roller with a new one, when the power is turned on, or when the stop time from the end of the previous printing is long, a local portion of the heating roller where the lower end of the oil roller is in contact is used. There was a risk that the oil would concentrate on the oil.

When the image is fixed on the recording medium in this state, the oil locally concentrated on the surface of the oil roller is transferred to the recording medium via the heating roller. The oil changes the gloss on the recording medium. In particular, gloss unevenness becomes remarkable in a high-density color image. In particular, this tendency becomes more prominent in color image OHP paper, and a portion of the OHP paper surface where oil is locally concentrated and adhered has a lens-like convex shape. Therefore, when the OHP paper is used, the transmitted light cannot go straight, and the projected image may be darkened.

In view of the above, it is an object of the present invention to provide a method for controlling the application of a release agent in a fixing device capable of fixing a stable high-quality image free of gloss unevenness and transmission unevenness of OHP paper onto a recording medium. I do.

[0009]

According to the first aspect of the present invention, a releasing agent supply member is provided to a fixing roller for fixing an unfixed image to the fixing surface by pressing against a fixing surface of a recording medium. A release agent application control method comprising a step of applying a release agent to the fixing roller in contact with the release roller, wherein the release agent application step is performed continuously with the release agent application step based on a fixing process state on the recording medium. The release agent supply member is brought into contact with a fixing roller, and the fixing roller is rotated for a predetermined time.

Therefore, when the release agent is unevenly distributed in the release agent supply member, the release agent may be locally concentrated on the release film formed on the fixing roller in contact with the release agent. Before the fixing to the medium, the release agent supply member and the fixing roller are brought into contact with each other and rotated for a predetermined time, so that not only a release film is formed on the surface of the fixing roller, but also the thickness of the release film. Can be made uniform. As a result, a good image can be fixed on the recording medium.

According to a second aspect of the present invention, when the release agent supply member is replaced with a new one,
The release agent supply member is brought into contact with the fixing roller continuously with the release agent application step, and the fixing roller is rotated for a predetermined time.

When the release agent supply member is replaced with a new one, the release agent supply member has maintained a fixed posture during packing, so that the release agent concentrates on the lower end portion of the release agent supply member. ing. Therefore, before the fixing is performed, the release agent supply member is brought into contact with the fixing roller and rotated, whereby the release film formed on the fixing roller surface becomes uniform, and a good image is fixed on the recording medium. be able to.

According to a third aspect of the present invention, in the first aspect of the invention, when the power is turned on, the release agent supply member is brought into contact with the fixing roller continuously with the release agent application step. The fixing roller is rotated for a predetermined time.

Since the operation of the release agent supply member has been stopped for a long time before the power is turned on, the release agent is concentrated on the lower end portion of the surface of the release agent supply member. Here, if the release agent supply member is brought into contact with the fixing roller, the release agent may adhere to a part of the fixing roller, but the release agent supply member may contact the fixing roller for a predetermined time. By touching and rotating,
The thickness of the release film formed on the surface of the fixing roller can be made uniform.

According to a fourth aspect of the present invention, in the first aspect of the present invention, when the time from the end of the previous print to the present print instruction exceeds a set allowable time, the release agent applying step is performed. The release agent supply member is continuously brought into contact with the fixing roller, and the fixing roller is rotated for a predetermined time.

In the image forming apparatus, the state of concentration of the release agent on the lower end of the release agent supply member differs depending on the elapsed time from the previous printing. Therefore, if it is within the allowable time, there is no effect on the recording medium, and if the allowable time is exceeded, it is determined that the effect of the release agent unevenness will occur, and the release agent supply member is brought into contact with the fixing roller. And rotate. Thereby, the thickness of the release film formed on the fixing roller surface becomes uniform.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the predetermined time is changed according to the type of the recording medium.

The sensitivity of the influence of the release agent unevenness of the fixing roller differs depending on the type of recording medium. For example, in the case of OHP paper, gloss unevenness is much more likely to occur than in the case of plain paper. Therefore, a good image can be fixed regardless of the type of recording medium by extending the contact time between the release agent supply member and the fixing roller depending on the type of recording medium and further uniformizing the release film. .

According to a sixth aspect of the present invention, in the first aspect of the present invention, the predetermined time is changed according to the type of image such as black and white or color.

Depending on the type of image, for example, whether the image is color or black and white, the sensitivity of the influence of the release agent unevenness of the fixing roller differs. For example, in the case of color, gloss unevenness is more likely to occur due to the release agent unevenness than in the case of black and white. Therefore, the contact time between the release agent supply member and the fixing roller is extended,
By making the release film more uniform, a good image is fixed regardless of the type of image information.

[0021]

FIG. 1 shows an image forming apparatus 10 including a fixing device 14 according to the present invention. As shown in FIG. 1, the image forming apparatus 10 is covered with a casing 12 and formed in a substantially box shape.

Below the image forming apparatus 10, a plurality of recording medium trays 16 (three recording medium trays 16A, 16B, and 16C are shown in the present embodiment) are provided. Each of the recording medium trays 16A, 16B, 16
C is provided with recording media 18 having different sizes such as B5 size, B4 size, A4 size, and A3 size. A half-moon roller 20 is provided in the recording medium tray 16 in the vicinity of the recording medium discharge section, and the sheets 18 are sent out one by one from the designated sheet tray 16.
It is transported in a predetermined direction by a plurality of transport roller pairs 22. In addition, when the image forming apparatus 10 instructs image formation on both sides (front and back) of the sheet 28, a sheet reversing unit 17 that reverses the front and back of the sheet 18 on which image formation on the front side is completed is provided. I have.

On one side of the image forming apparatus 10, a manual feed tray 24 for manually inserting paper 18 as necessary.
Are arranged. A half-moon roller 20 is provided near the paper insertion portion of the manual feed tray 24, similarly to the above-described paper tray 16, so that the paper 18 can be sent out one by one.

A fixing device 1 is provided above the image forming apparatus 10.
4 is provided with a discharge tray 26 from which the sheet 18 on which a desired image is fixed is discharged.

Paper tray 16 in image forming apparatus 10
In the upper part of the image data, image data obtained by reading an original with a scanner and performing various image processing (because the image forming apparatus 10 in the present embodiment is for a color image, image processing is performed by yellow, magenta, cyan, (Which is converted into image data of four colors of black)
And an image forming unit 28 including a fixing device 14 for fixing a desired image on the sheet 18 and the like.

The optical scanning device 32 includes a light source, a rotating polygon mirror 3
4. fθ lens, cylindrical mirror, reflection mirror 3
6 and the like. A laser beam emitted from a light source (not shown) is deflected by a rotating polygon mirror 34 and fθ lens, cylindrical mirror, reflection mirror 36
Irradiation is performed on the photoreceptor 30 via the like.

A charger 3 is provided around the photosensitive member 30.
8, a rotary developing device 40, an intermediate transfer member 42 composed of an IBT belt, a photoreceptor cleaner 44, and a static elimination lamp (not shown) are provided.

The photosensitive member 30 rotates at a constant speed in the direction of arrow A shown in FIG. The charging member 38 negatively charges the photoconductor 30 uniformly. The rotary developing device 40 includes four color toners 46Y of yellow, magenta, cyan, and black.
46M, 46C and 46Bk are supplied. The intermediate transfer body 42 is wound around a plurality of rollers 48, and the rotation of the rollers 48 causes an arrow B shown in FIG.
Move at a constant speed in the direction. Photoreceptor cleaner 44
Removes toner remaining on the photoreceptor 30 without being transferred to the intermediate transfer body 42. Further, the charge removing lamp removes the charge of the photosensitive member 30 after the residual toner is removed by the photosensitive member cleaner 44.

Further, an image detection sensor 51 and a cleaner 50 for the intermediate transfer member are disposed around the intermediate transfer member 42. The image detection sensor 51 is provided upstream of the transfer unit 52 in the rotation direction of the intermediate transfer body 42, and detects the presence or absence of a toner image formed on the intermediate transfer body 42. The intermediate transfer body cleaner 50 is provided downstream of the transfer unit 52 in the rotation direction of the intermediate transfer body 42, and after the transfer of the toner image from the intermediate transfer body 42 to the sheet 18 is completed, the intermediate transfer body 42 The toner remaining on the surface is removed.

The photosensitive member 30 rotating in the direction of arrow A is uniformly negatively charged by the charger 38, and
First, a first-color black latent image is formed on the photoreceptor 30 by the laser light emitted from the photoreceptor 2. This latent image is developed with black toner by the black developing device of the rotary developing device 40. The developed black toner image is transferred to the intermediate transfer member 42.
Is transferred to The toner remaining on the photoconductor 30 without being transferred is removed by a cleaner (not shown), and the photoconductor 30 is discharged by a discharge lamp.

Then, the photosensitive member 30 is uniformly negatively charged again by the charger 38, and the second color yellow image is formed. In this manner, a total of four color toner images are sequentially transferred to the intermediate transfer member 26 from the third color magenta to the fourth color cyan. When the transfer of the four color toner images to the intermediate transfer member 42 is completed, a final toner image is formed on the surface of the intermediate transfer member 42.

Below the intermediate transfer member 42, an intermediate transfer member 4
A transfer section 52 for transferring the final toner image formed on the sheet 2 to the sheet 18 is provided. The paper 18 is conveyed from the paper tray 16 provided with the paper 18 of the designated size to the transfer unit 52 by the conveyance roller pair 22 as described above.

The fixing device 14 is provided downstream of the transfer unit 52 in the transport direction of the sheet 18. In the fixing device 14, a predetermined image is formed on the sheet 18 by performing a fixing process on the sheet 34 onto which the final toner image has been transferred. The details of the fixing device 14 will be described below.

As shown in FIG. 2, the fixing device 14
A heating roller 56 for fusing and fixing the toner transferred on the sheet 8 to the sheet 18, a pressure roller 58 for sandwiching and pressing the sheet 18 together with the heating roller 56, and a separation roller on the surface of the heating roller 56. And an oil roller 60 for supplying oil as a mold agent.

The heating roller 56 is formed of iron metal hollow gold having a thickness of about 3 mm. The contact surface with the paper 18, that is, the surface of the heating roller 56 has a thickness of 2 mm.
About a rubber layer is formed. The heating roller 56
A halogen lamp as a heating element (not shown) is built in the inside.

The pressing roller 58 has a rubber layer having a thickness of about 1 mm formed around the iron core bar, similarly to the heating roller 56 described above. The pressure roller 58 presses the heating roller 56 with a constant pressure by a spring (not shown). Thereby, the heating roller 56 and the pressure roller 58
As a result, the sheet 18 is nipped and conveyed. In this way, when the sheet 18 passes between the heating roller 56 and the pressure roller 58, the toner is melted and fixed on the sheet 18 by pressure.

The oil roller 60 is composed of an oil holding layer formed of a foam or the like impregnated with oil, and an oil control layer that allows oil to permeate the outer peripheral surface of the roller by gravity or centrifugal force. The oil roller 60 is rotatably supported inside the cassette 62. The rotation shaft 65 of the oil roller 60 is supported by one end of a lever 66 and enters an elliptical guide groove 63 provided on a side surface of the cassette 62. A cam 64 is in contact with the other end of the lever 66, and the eccentric movement of the cam 64 causes the lever 66 to rotate about the rotation shaft 67. Note that the lever 66 is always cam 64 by a spring 69.
Is biased to the side.

With this configuration, the cam 64
Due to the eccentric movement of, the rotating shaft 65 with which one end of the lever 66 abuts moves while being guided by the guide groove 63. That is,
The oil roller 60 is configured to be able to contact and separate from the heating roller 56.

When the oil in the oil roller 60 is consumed, the cassette 62 is replaced together with the cassette 62.

As shown in FIG. 3, a gear 70 is supported at one end of a cam shaft 68 on which the cam 64 is formed, and a rotation regulating member 7 for regulating the amount of rotation of the cam 64.
2 are formed.

As shown in FIG. 4, the gear 70 has a large diameter portion 73 having teeth 71 formed on the outer peripheral surface, and a small diameter portion continuous with the large diameter portion 73 and having a one-way clutch 74 provided on the outer peripheral surface. 7
5 is comprised. The one-way clutch 74 transmits the rotational force of the gear 70 only in one direction (the direction of arrow C) by slidingly contacting the inner peripheral surface of the rotation regulating member 72.

The gear 70 meshes with a gear (not shown) provided on a rotating shaft of a member which is always driven when the power is turned on, and is always rotating in the C direction.

On the outer peripheral surface of the rotation restricting member 72, claws 76 and 78 are formed at different positions in the axial direction and the rotational direction of the camshaft 68 so as to project therefrom. The claws 76, 78
The rotation of the rotation restricting member 72 is restricted by being locked by locking portions 82 and 84 of a locking member 80 described later.

The locking member 80 has a solenoid 86 at one end,
A spring 88 is connected to the other end, and rotates in the directions of arrows D and E around the rotation shaft 90 by turning on / off the solenoid 86.

That is, when the solenoid 86 is biased, the drive shaft 87 of the solenoid 86 is shortened, the locking member 80 is rotated about the rotation shaft 90 in the direction of arrow D, and the locking portion 84 is moved. While being separated from the claw 78 of the rotation regulating member 72, the locking portion 82 comes into contact with the outer peripheral surface of the rotation regulating member 72. Rotational force is transmitted to the rotation restricting member 72 by the one-way clutch 74, and rotates together with the gear 70 in the direction of arrow C. As a result, the pawl 76 is fixed to the locking portion 8 of the locking member 80.
2 to stop (restrict) the rotation of the camshaft 68. As a result, the cam 64 performs an eccentric motion.
As a result, the lever 66 rotates clockwise about the rotation center shaft 67, and the movement of the rotation shaft 65 guided by the guide groove 63 causes the oil roller 60 to contact the heating roller 56 (the solid line in FIG. 2 →). Two-dot chain line).

When the solenoid 86 is deenergized, the drive shaft 87 of the solenoid 86 extends, and the locking member 80 rotates about the rotation shaft 90 in the direction of arrow E, and 82 is separated from the pawl 76 of the rotation restricting member 72, and the locking portion 84 contacts the outer peripheral surface of the rotation restricting member 72. Rotational force is transmitted to the rotation regulating member 72 by the one-way clutch 74, and the rotation regulating member 72 rotates together with the gear 70 in the direction of arrow C. As a result, the pawl 78 is locked by the locking portion 84 of the locking member 80, and the rotation of the camshaft 68 is stopped (regulated). As a result, the cam 64 performs an eccentric motion. As a result, the lever 66 rotates counterclockwise about the rotation shaft 67, and the movement of the rotation shaft 65 guided by the guide groove 63 causes the oil roller 60 to be separated from the heating roller 56 (two-dot chain line in FIG. 2). Part → solid line part).

The on / off control of the solenoid 86 is performed by a microcomputer including a CPU, a ROM, a RAM, and an input / output port (not shown).
A control routine shown in FIGS. 10 to 12 described later is controlled by a control circuit 112 stored in advance.

On the side of the cassette 62, a mechanism for detecting whether or not the oil roller 60 is new is provided. As shown in FIG. 7, one end of the cassette 62 has a first plate 9 made of a conductive material.
The second plate 94 and the second plate 94 are fixed at a predetermined distance from each other, and a third plate 96 made of a conductive material is fixed on the two plates 92 and 94. The third plate 96 has a triangular cut 98 for cutting.
Is provided.

The first to third plates 92, 94, 96 are in contact with first to third conductive portions 102, 104, 106 formed of a conductive material in the sensor 100. The first to third conducting parts 102, 104, 106 are shown in FIG.
As shown in the figure, the first to third plates 92 are formed by leaf springs bent in a U-shape and have predetermined elasticity.
94 and 96 respectively.

A cutter 110 provided on a main body drive shaft 108 rotatably supported by the casing 12 is provided so as to be able to enter the cut 98 of the third plate 96 (see a two-dot chain line portion in FIG. 8). ).

Therefore, when the cassette 62 has just been replaced, the first conducting portion 102 and the second conducting portion 104 of the sensor 100 conduct through the first plate 92, the third plate 96, and the second plate 94. By this conduction, the sensor 100 detects that the cassette 62 is new,
A new product detection signal is output to the control circuit 112.

After replacement of the cassette 62, the paper 1
8, when the unfixed image is fixed, the main body drive shaft 108 rotates in the direction of arrow F, and the cutter 110 moves the third plate 9.
6. Enter the notch 98 of FIG. Thereby, as shown in FIG. 9, the third plate 96 is cut and divided into two parts. As a result, the first conductive portion 10 of the sensor 100
2 and the second conducting portion 104 are interrupted. As a result, the sensor 100 determines that the cassette 62 is not new (hereinafter, referred to as “new”).
And outputs an old product detection signal to the control circuit 112.

Next, the operation of the embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. The control routines of FIGS. 10 to 12 are stored in the control circuit 112 in advance as described above.

Here, first, the paper 18 is transferred to the fixing device 14.
Roller 56 and oil roller 6 before being conveyed to
The setting (setting the flag F = 1) of the condition that both rollers are rotated two turns in a state where 0 is contacted (hereinafter, referred to as idle rotation of the heating roller 56) will be described.

In the first idling condition setting control routine, as shown in FIG. 11, conditions are set based on the following determination before a print instruction.

First, in step 122, it is determined whether the power of the image forming apparatus 10 has just been turned on. This is because before the power is turned on in the image forming apparatus 10,
It is considered that the oil roller 60 in the fixing device 14 was kept in a constant posture for a long time without rotating. Therefore, there is a possibility that the oil may be concentrated at the lower end portion (6 o'clock direction) of the outer peripheral surface of the oil roller 60.
It is determined that the oil (oil film) applied to the surface needs to be evenly distributed. Therefore, if the power has just been turned on, the routine proceeds to step 126, where the flag F = 1.
And Otherwise, go to step 124.

In step 124, it is determined whether the cassette 62 including the oil roller 60 has been replaced. Here, it is determined whether the cassette 62 has just been replaced (new) or not (old) based on the detection signal input from the sensor 100 to the control circuit 112. This is the cassette 62
If the new oil roller 6 has just been replaced,
This is because oil is considered to be held in a constant posture until it is replaced, and it is considered that oil is concentrated at the lower end of the oil roller 60. Therefore, if it has just been replaced, it is determined that the idle rotation of the heating roller 56 is necessary, and the routine proceeds to step 126, where the flag F = 1.

Thus, the control routine for setting the first idling condition is repeated. The control routine for setting the second idling condition (see FIG. 12) is started when the start of image processing is input from the personal computer to the control unit 112 by a signal.

First, in step 132, the control circuit 112 determines the type of the paper 18 based on an image processing input signal from a personal computer or the like (not shown). Here, it is determined whether the paper is plain paper or OHP paper.

In step 134, the interval (rest time) since the last fixing in the fixing device 14 is read out to the control circuit 112.

At step 136, it is determined whether or not it corresponds to the circle in the table shown in FIG. This is OH
Since gloss unevenness due to uneven distribution of oil in the heating roller 56 is more likely to occur in the P sheet than in the plain sheet, conditions under which idle rotation is not required (allowable rest time of the oil roller 60) are severe. That is, the idling condition differs depending on the type of the paper 18. As shown in the table of FIG. 13, if the rest time is less than 30 minutes for plain paper, the influence of uneven distribution of oil on the oil roller 60 does not affect the paper 18 as gloss unevenness via the heating roller 56. On the other hand, in the case of the OHP sheet, if the rest time is not shorter than 5 minutes, the oil unevenness of the oil roller 60 appears as gloss unevenness on the sheet 18.

Therefore, if the condition of に お い て is not satisfied (x) in the table shown in FIG. 13, it is determined that the idle rotation is necessary, and the routine proceeds to step 138, where the flag F = 1.
And

As described above, in the second idling condition setting control,
Each time an image processing signal is input from the personal computer to the control circuit 112, the above condition setting control is performed.

The operation control of the oil roller 60 shown in FIG. 10 is performed with the idling condition setting control being performed in advance in this manner.

First, at step 102, it is determined whether or not a print instruction input signal has been received from the personal computer to the control circuit 112. The process proceeds to step 104 only when a print instruction is issued.

In step 104, the print size and the number of continuous prints are integrated on the basis of the input signal input from the personal computer to the control circuit 112, and this is used as the count. Here, the size of the paper 18 is A
The number of counts is changed depending on the size, such as 1 count for 4 sizes and 2 counts for A3 size. In addition, the rest time from the previous print is read out, and the application time T is set based on the rest time and the count based on the table shown in FIG.

The reason for setting the application time T based on the count number in this manner is that the amount of oil consumed (adhered to the paper 18) differs depending on the size of the paper 18. This is because it is necessary to adjust the application time T that rotates while being brought into contact with the paper 18 according to the size of the paper 18. In addition, in the case of continuous printing, there is not enough time to apply oil to the heating roller 56 each time one sheet is fixed, so that an amount of oil corresponding to the number of continuous prints is applied to the heating roller 56 in advance. Because you have to put it.

The reason for changing the application time T according to the rest time is that if the rest time is short (within 5 minutes), it takes time for the oil to seep out from the control layer on the surface of the oil roller 60. This is because a sufficient time is required to apply a predetermined amount of oil to the heating roller 56.

When the rest time is short (within 5 minutes), the count is kept as it is, and is added to the new count at the next printing. If the rest time is long, clear the count number. If the rest time is medium, the count number is set to four.

This is because if the rest time is short, the surface of the oil roller 60 is not sufficiently oozed with oil, so that a margin is provided.

For example, after the power is turned on, A4 size paper 1
If three 8 were printed, the count would be 1 × 3 = 3,
The rest time is 5 minutes or more, the application time is 3.2 seconds, and the count number is cleared (3 → 0).

On the other hand, after printing 19 sheets of A4 size paper 18 in the previous printing, the A
3 is printed, the previous count 19 (1
× 19) and the current count number 4 (2 × 2) are added to the count number 23, and the count number is held as it is with the application time of 24 seconds.

At step 106, it is determined whether or not the flag F = 1. That is, it is determined whether or not idling time is required to equalize the unevenness of the oil film of the heating roller 56 due to uneven distribution of oil in the oil roller 60. If idling is required (flag F = 1), step 10
Proceed to 8. If idle rotation is not required (flag F = 0),
Proceed to step 110.

In step 108, the application time T is changed to T + α. That is, the heating roller 60 is applied during the application time T for applying the amount of oil adhering to the paper 18 to the heating roller 56.
Is added to the time α for making the oil film formed uniform.

At step 110, the control circuit 112
The solenoid 86 is energized by an output signal from the controller 86. As a result, the locking member 80 rotates in the direction D, and the locking portion 82 locks the claw 76 (see FIGS. 6 to 5). The rotation of the rotation restricting member 72 and the cam shaft 68 in the direction D causes the cam 64 to perform an eccentric motion. As a result, the oil roller 60
Abuts on the heating roller 56 (see a solid line part → a two-dot chain line part in FIG. 2).

Then, by driving and rotating the heating roller 56, oil is applied from the oil roller 60 to the outer peripheral surface of the heating roller 56. At this time, since the heating roller 56 and the oil roller 60 are brought into contact with each other and rotated two or three times,
The thickness of the oil film formed on the heating roller 56 can be made uniform.

In step 112, it is determined whether or not the application time T has elapsed. By applying the oil during the application time T, an appropriate oil film is formed on the heating roller 56 regardless of whether or not the oil is unevenly distributed on the oil roller 60 in accordance with the paper size and continuous / discontinuous printing. You. After the elapse of the application time T, the process proceeds to step 114.

At step 114, the solenoid 86 is deactivated. As a result, the locking member 80 rotates in the direction E to separate the locking portion 82 from the outer peripheral surface of the rotation restricting member 72, and causes the locking portion 84 to abut on the outer peripheral surface of the rotation restricting member 72 (see FIG. 5 →). See FIG. 6). Thus, the locking portion 84 locks the claw 78 to restrict the rotation of the rotation restricting member 72, that is, the rotation of the cam 64. By this series of operations, the lever 66 rotates to move the rotating shaft 65, and the oil roller 60 is
6 (see two-dot chain line part → solid line part in FIG. 2). Thus, the application of the oil to the heating roller 54 is completed.

Next, at step 116, the flag F is returned to 0. Then, in step 118, the unfixed image is fixed by pressing the conveyed sheet 18 between the heating roller 56 and the pressing roller 58 under pressure.

This series of operation control of the oil roller 60 is performed again from step 102. Since the operation control of the oil roller 60 is performed in this manner, when there is a possibility that oil is concentrated on a specific portion of the oil roller 60,
Since the oil roller 60 and the heating roller 56 are brought into contact with each other to rotate the application time T (T + α), the thickness of the oil film formed on the heating roller 56 can be made uniform, and the unfixed image is fixed. The image on the paper 18 has good image quality without gloss unevenness.

Further, since the application time T is set to be changed according to the rest time and the count number, an appropriate amount of oil is applied from the oil roller 60 to the heating roller 56.

The application time T can be changed based on a table similar to the table shown in FIG. 13 depending on whether the unfixed image is color or monochrome.

In the oil roller operation control of this embodiment, the table shown in FIG. 14 is used to set the application time T in step 104, but it is also possible to use the table shown in FIG. In this case, paper 1
The number of counts is calculated from the size of No. 8 and the number of continuous prints, and the application time T is set based only on the number of counts. The count is cleared every time. Therefore, each time, the application time T can be determined only from the number of prints and the size.

Further, in the present embodiment, a print instruction is input from the personal computer to the control circuit 112. However, the print instruction may be input from the operation panel of the image forming apparatus 10, or another input method may be used. .

[0085]

According to the first aspect of the present invention, even if the release agent is concentrated on a part of the release agent supply member, the thickness of the release film is uniform on the fixing roller. Therefore, a good image can be formed without causing gloss unevenness or the like in the image of the recording medium by the fixing process.

According to the second aspect of the present invention, since the above-described configuration is employed in the first aspect, even when the release agent supply member is replaced with a new one, an unfixed image is suitably fixed on the recording medium.

According to the third aspect of the present invention, since the above-described configuration is adopted in the first aspect of the present invention, an unfixed image is suitably fixed on a recording medium even when the power is just turned on.

According to a fourth aspect of the present invention, since the above-described configuration is employed in the first aspect of the present invention, even if a sufficiently long time has elapsed since the previous printing, the uneven distribution of the release agent in the release agent supply member. The unfixed image is suitably fixed on the recording medium without being affected by the image.

According to the fifth aspect of the present invention, since the above-described configuration is employed in the first aspect of the present invention, the contact time of the release agent supply member with respect to the fixing roller is adjusted in accordance with the type of the recording medium, and the time is appropriately adjusted. An appropriate amount of release agent can be applied to the fixing roller.

According to the sixth aspect of the present invention, since the above-described configuration is employed in the first aspect of the present invention, the contact time of the release agent supply member with respect to the fixing roller is adjusted in accordance with the type of the image, and an appropriate time is provided. An amount of release agent can be applied to the fuser roller.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram of an operation of the fixing device according to the embodiment of the present invention.

FIG. 3 is a perspective view of a main part of a camshaft rotation mechanism according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view of a main part of the camshaft rotation mechanism according to the embodiment of the present invention.

FIG. 5 is an operation explanatory view of the camshaft rotation mechanism according to the embodiment of the present invention.

FIG. 6 is an operation explanatory view of the camshaft rotation mechanism according to the embodiment of the present invention.

FIG. 7 is a plan view of the new article detection mechanism according to the embodiment of the present invention.

FIG. 8 is a side view of the new article detection mechanism according to the embodiment of the present invention.

FIG. 9 is a plan view of the new article detection mechanism according to the embodiment of the present invention.

FIG. 10 is a flowchart illustrating a control routine according to the embodiment of the present invention.

FIG. 11 is a flowchart illustrating a control routine according to the embodiment of the present invention.

FIG. 12 is a flowchart illustrating a control routine according to the embodiment of the present invention.

FIG. 13 is a control table according to the embodiment of the present invention.

FIG. 14 is a control table according to the embodiment of the present invention.

FIG. 15 is a control table according to the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 image forming apparatus 14 fixing device 18 paper (recording medium) 56 heating roller (fixing roller) 60 oil roller (release agent supply member)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Nobumitsu Kouchi, Inventor 3-7-1, Funai, Iwatsuki-shi, Saitama Fuji Xerox Co., Ltd. Iwatsuki Works (72) Inventor Kazumi Inaba 2274 Hongo, Ebina-shi, Kanagawa Fuji Xerox Corporation Ebina Office (72) Inventor Yasutaka Naito 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Corporation Ebina Office (72) Inventor Kunimasa Aoshima 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd. In business office

Claims (6)

[Claims] 1. A releasing agent supply member is brought into contact with a fixing roller for fixing an unfixed image to the fixing surface by pressing against a fixing surface of a recording medium to apply a releasing agent to the fixing roller. A method of controlling the release agent application, the method further comprising: contacting the release agent supply member with the fixing roller continuously with the release agent application process based on a fixing process state on the recording medium. A method of controlling the application of a release agent in a fixing device, wherein the fixing roller is rotated for a predetermined time. 2. When the release agent supply member is replaced with a new one, the release agent supply member is brought into contact with the fixing roller continuously with the release agent application step, and the fixing roller is contacted for a predetermined time. 2. The method according to claim 1, wherein the releasing agent is rotated. 3. When the power is turned on, the releasing agent supply member is brought into contact with the fixing roller continuously with the releasing agent applying step, and the fixing roller is rotated for a predetermined time. The method for controlling the application of a release agent in a fixing device according to claim 1. 4. When the time from the end of the previous print to the present print instruction exceeds a set allowable time,
2. The release agent for a fixing device according to claim 1, wherein the release agent supply member is brought into contact with the fixing roller after the release agent application step, and the fixing roller is rotated for a predetermined time. Application control method. 5. The method according to claim 1, wherein the predetermined time is changed in accordance with a type of a recording medium. 6. The method according to claim 1, wherein the predetermined time is changed according to the type of image such as black and white or color.