JPH05150675A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent heat damage, etc., of a fixing film in the image forming device where a film fixing device is utilized as the image heat fixing device. CONSTITUTION:In the image forming device provided with a heating body 14 heated by energization, a film 18 which is driven slidingly over the heating body 14, and which is the film fixing device 11 by which a toner image Ta is heated and fixed by heat from the heating body 14 through the film 18 by being moved and passed through the position of the heating body 14 with the film 18 with a toner image carrying recording material P from an image forming part adhered to a surface opposite to the heating body 14 side of the film 18, the speed of the film 18 which is driven at a first speed is changed over to a second speed after energizing to the heating body 14 of the heating device 11 is stopped, and then the driving of the film 18 is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image fixing device having a heating body which generates heat when energized and a film which is slidably moved on the heating body. An image that is a film type fixing device in which the toner image bearing recording material from the image forming unit is brought into close contact with the surface of the film and moved through the position of the heating body together with the film to heat and fix the toner image by the heat from the heating body through the film. Forming apparatus

More specifically, electrophotographic devices, printers,
A recording material (transferring material) such as an electrostatic recording device or a facsimile is formed by using a toner made of a heat-meltable resin by an appropriate image forming process means (image forming section) such as electrophotography, electrostatic recording, magnetic recording, etc. An unfixed toner image corresponding to the target image information is formed and carried on the surface of the material, photosensitive paper, electrostatic recording sheet, etc. by an indirect (transfer) method or a direct method, and the toner image is formed on the film as described above. The present invention relates to an image forming apparatus in which a fixing device heats and fixes the surface of a recording material.

An image forming apparatus of a type in which a color is formed by applying light, heat or pressure to microcapsules contained in a recording material or a transfer film,
An image forming device that sharpens or fixes an image with a film type fixing device, or a recording material carrying an image with a film type fixing device is heated to improve the surface properties such as gloss (gloss), and the image is presumed An image forming apparatus configured to do so is also included.

[0004]

2. Description of the Related Art Conventionally, a heat roller system has been generally used as an image heating and fixing device of an image forming apparatus. This is basically composed of a heating roller and a pressure roller in pressure contact with this roller, and heats and fixes the image by introducing and passing a recording material between the both rollers.

However, since the heat roller system has a large heat capacity, the heating roller takes a long time to rise to a predetermined temperature and lacks quick startability. The same applies to other heat fixing devices such as a hot plate system and a heat chamber system.

The above-mentioned film type fixing device is known from Japanese Patent Application Laid-Open No. 63-313182, which was previously proposed by the present applicant, and more specifically, it is thin (for example, 40 μm).
m) heat-resistant film (sheet), a means for moving the film, a heating element (heater) fixedly supported on one side of the film, and a heater on the other side. It has a pressure member such as a pressure roller which is arranged so as to face the heating body and which makes the developed image bearing surface of the recording material to be image-fixed to the heating body closely adhere to the heating body. When fixing is performed, the recording material conveyed between the film and the pressure member is moved forward at the same speed as the recording material to be image-fixed, and the traveling moving film is sandwiched between the heating member and the pressure member. A recording material is introduced into and passed through a fixing nip portion, which is a fixing portion formed by pressure contact, so that the surface of the recording material bearing the developed image is heated by the heating member through the film to form a developed image (unfixed toner image). Heat energy is applied to soften and melt Tighten, then an image heating fixing apparatus which is based on that are spaced from each other by a separation point of the recording material and the film after fixing portion passes.

The film may be of an endless type so as to be rotated and conveyed for repeated use, or it may be of an apparatus structure for feeding an end-rolled film and running it. The pressure member may be rotationally driven to serve as a film movement driving means.

In such a film-type fixing device, a low heat capacity heater can be used as a heating body, and a film having a thin wall and a low heat capacity and good heat transfer efficiency can be used. The time can be shortened, the quick start performance is good, and the power consumption can be reduced.

[0009]

(A) In the film type fixing device using the film that slides on the heating body as described above, if the film is constantly driven, the surface of the film and the heating body will be worn and noise will be generated. It is preferable to stop the film during non-fixing.

However, if the film is stopped and allowed to stand while the heating element is in a high temperature state, the heat causes the film to stick to a pressure roller as a pressure member or foreign matter to stick to the film. There was a problem of breaking.

Therefore, a method has been proposed in which the film is continuously driven after the power supply to the heating body is stopped, and then the film drive is stopped. However, in this example, the film is driven even after the fixing operation is completed. The motor continues to run for a certain period of time, giving the operator an unnatural feel.

(B) When the film is constantly driven, during continuous execution of image forming cycles (during continuous copying),
Since the heat of the heating element is wastefully consumed by the film during the period (paper interval) between one recording material and the next recording material at the time of non-fixing, wasteful power is consumed between the paper. Become.

Therefore, it is desirable to stop the driving of the film between the sheets during the non-fixing period to prevent the wasteful discharge of heat.

However, similar to the above (A), if the film is stopped while the heating element is in a high temperature state, the heat may cause the film to stick to the pressure roller or foreign matter to stick to the film. It may damage the film.

(C) In order to reduce the sliding friction between the heating body and the film, a grease such as heat resistant fluorine-based grease is applied to the sliding surface between the heating body and the film to form a lubricant.

In this case, since grease has a large viscosity at a low temperature due to its characteristics, a large torque is momentarily generated when the fixing device is started (when the film is driven) when the device is in a cold state. ..

In order to deal with this, it is necessary to increase the strength of the drive transmission means, such as gears, and to increase the drive torque of the motor of the drive means, which leads to the drawbacks of increased cost and increased size of the apparatus. Occur.

Further, since the film is being driven when the temperature of the heating body is raised during non-fixing, the heat of the heating body that is in the process of raising temperature escapes to the film in the driving state, so that the rise of temperature is delayed. There are drawbacks. As a measure against this,
Although it is possible to stop the film while the temperature is rising, there is a problem that thermal damage to the film becomes large when stopped and heated.

(D) As in the case of (C) above, as a problem due to the large viscosity at low temperature due to the characteristics of grease, when the previous image forming operation is completed, as in the case of performing the image forming operation in the morning, for example. When a next image forming operation is performed after a certain time from the above, a large torque is momentarily generated when the fixing device is started.

In order to deal with this, similarly to (C), it is necessary to increase the strength of the drive transmission means, for example, the gears, or increase the drive torque of the motor, which is the drive means, thereby increasing the size of the device. However, there is a drawback that the cost is increased.

Further, since the heat of the heating element escapes to the film because the film is driven at the time of raising the temperature, the state where the temperature of the fixing device is completely cooled, as in the case of forming an image for a certain time or more, is performed. However, there is a drawback that the rise of temperature becomes slow.

As a countermeasure against this, in this case as well, the film may be stopped while the temperature is rising, but if stopped and heated, thermal damage to the film becomes large,
As a result, it will damage the film,
Realization is impossible.

(E) In the conventional film type fixing device, the length of the recording material passing through the fixing device (the length in the recording material conveying direction)
However, since the film driving speed (fixing speed) is constant, when the recording material is short, the time in the non-fixing state in which there is no recording material in the fixing device is long and the electric power is wasted during that time. ..

Further, the sliding of the film with the heating body or the like when there is no recording material in the fixing device is uselessly damaging the film.

Further, small recording materials are often thick paper such as postcards and business cards, but if the paper is thick, the amount of heat that escapes to the paper when passing through the fixing device becomes large, which in turn lowers the fixing temperature. Poor fixing may occur.

(F) In the case of a small-sized recording material such as a business card or a postcard, the temperature of the portion of the film which is not in contact with the recording material is higher than that of the portion in contact with the recording material, so that the film portion receives the film. It had the drawback of increasing the heat damage.

Further, in the case of a recording material having a small size, the total amount of energy required for fixing is smaller than that of a recording material having a large size, but since the fixing speed is constant in the conventional apparatus, there is no recording material in the fixing device. Since the fixing device consumes unnecessary power during this time, the total amount of energy used for fixing to a small recording material as well as to a large recording material Did not change much and the power was not being used effectively.

Further, recording materials of small size are often thick papers such as postcards and business cards. However, if the recording material is thick, a large amount of heat escapes to the recording material, which in turn lowers the temperature of the heating element and causes poor fixing. There was a risk of causing.

An object of the present invention is to solve the above-mentioned problems in an image forming apparatus which employs a film type fixing device as an image fixing device.

[0030]

[Means for solving the problem] ◎ (1) to (3) below
Is the invention according to claims 1 to 3, and is a means for solving the above-mentioned problem (A).

(1) The image fixing device has a heating body that generates heat when energized and a film that is slidably driven on the heating body, and an image forming unit is provided on the surface of the film opposite to the heating body side. In the image forming apparatus, which is a film-type fixing device, in which the toner image-bearing recording material from (3) is closely adhered and the toner image is heated and fixed by the heat from the heating body through the film by moving and passing through the position of the heating body together with the film, An image forming apparatus characterized in that after the power supply to the heating element of the fixing device is stopped, the speed of the film being driven at the first speed is switched to the second speed, and thereafter the driving of the film is stopped.

(2) It is characterized in that it has means for deciding the timing for stopping the film driving after the power supply to the heating element of the fixing device is stopped, and the film driving is stopped when the timing is detected ( The image forming apparatus according to 1).

(3) The first speed is a normal drive speed of the film when the toner image is fixed, and the second speed is faster than the first speed. Image forming device.

(4) The following (4) to (6) are the inventions according to claims 4 to 6 and are means for solving the problem of the above (B).

(4) The image fixing device has a heating body that generates heat when energized and a film that is slidably driven on the heating body, and an image forming unit is provided on the surface of the film opposite to the heating body side. In the image forming apparatus, which is a film-type fixing device, in which the toner image-bearing recording material from (3) is closely adhered and the toner image is heated and fixed by the heat from the heating body through the film by moving and passing through the position of the heating body together with the film, When the recording material is present in the fixing device, the film is driven at the first speed, and when the recording material leaves the fixing device, the film is driven at the third speed.
An image forming apparatus characterized in that the speed of the film is changed and when the recording material is introduced into the fixing device again, the film drive is changed to the first speed.

(5) Driving the film from the first speed to the third
A means for determining the timing T1 for switching to the speed and a means for determining timing T2 for switching from the third speed to the first speed are provided, and when the timing T1 is detected, the film drive is switched from the first speed to the third speed. When the timing T2 is detected, the film drive is switched from the third speed to the first speed.

(6) The first speed is a normal drive speed of the film when fixing the toner image, and the third speed is slower than the first speed (4). Alternatively, the image forming apparatus according to (5).

(7) The following (7) to (9) are the inventions according to claims 7 to 9 and are means for solving the problem of the above (C).

(7) The image fixing device has a heating body which generates heat when energized and a film which is slidably moved on the heating body, and an image forming section is provided on the surface of the film opposite to the heating body side. In the image forming apparatus, which is a film-type fixing device, in which the toner image-bearing recording material from (3) is closely adhered and the toner image is heated and fixed by the heat from the heating body through the film by moving and passing through the position of the heating body together with the film, An image characterized in that the film is driven at a third speed from the start of the fixing device until the recording material is introduced into the fixing device, and the film is driven at the first speed when the recording material is introduced into the fixing device. Forming equipment.

(8) Means for determining the timing T1 for starting the driving of the film at the third speed after starting the image forming operation of the image forming unit, and means for determining the timing T2 for switching the film driving to the first speed. Have and timing T1
When the temperature is detected, energization of the heating element and the driving of the film at the third speed are started, and when the timing T2 is detected, the driving of the film is switched to the first speed (7).
The image forming apparatus described.

(9) The first speed is a normal driving speed of the film when fixing the toner image, and the third speed is slower than the first speed (7). Alternatively, the image forming apparatus according to (8).

The following (10) to (15) are claims.
The invention is described in any one of (1) to (15), which is a means for solving the problem (D).

(10) The image fixing device has a heating body that generates heat when energized and a film that is slidably driven on the heating body, and an image forming unit is provided on the surface of the film opposite to the heating body side. In the image forming apparatus, which is a film-type fixing device, in which the toner image-bearing recording material from (3) is closely adhered and the toner image is heated and fixed by the heat from the heating body through the film by moving and passing through the position of the heating body together with the film, It has a means for detecting the temperature of the heating body of the fixing device, and when the temperature detected by the temperature detecting means at the start of the image forming operation of the image forming section is below a predetermined temperature, the film is driven at the third speed. An image forming apparatus characterized in that when the recording material is introduced from the image forming section to the fixing device, the film drive is switched to the first speed.

(11) When the film is being driven at the third speed, it has means for detecting the timing for switching the film drive to the first speed, and when this timing is detected, the film drive is set to the first speed. The image forming apparatus according to (10), which is switched.

(12) The first speed is the normal drive speed of the film when the toner image is fixed, and the third speed is
The image forming apparatus according to (10) or (11), wherein the speed is slower than the first speed.

(13) The image fixing device has a heating body which generates heat when energized and a film which is slidably driven on the heating body, and an image forming section is provided on the surface of the film opposite to the heating body side. In the image forming apparatus, which is a film-type fixing device, in which the toner image-bearing recording material is closely adhered to the recording material and is moved through the position of the heating body together with the film to heat and fix the toner image by the heat from the heating body through the film, When the next image forming operation is started after measuring the time from the end of the forming operation to measuring the time of a predetermined time or more, the film of the fixing device is driven at the third speed, An image forming apparatus characterized in that the film drive is switched to a first speed when fixing a toner image.

(14) When the film is driven at the third speed, it has a means for detecting the timing for switching the film driving speed to the first speed, and when this timing is detected, the film driving speed is changed to the first speed. The image forming apparatus according to (13), characterized in that the image forming apparatus is switched to.

(15) The first speed is the normal drive speed of the film when the toner image is fixed, and the third speed is
The image forming apparatus according to (13) or (14) is characterized in that the speed is slower than the first speed.

◎ The following (16) and (17) are claims 16
The invention according to 17 is a means for solving the problem (E).

(16) The image fixing device has a heating body that generates heat when energized and a film that is slidably driven on the heating body, and an image forming unit is provided on the surface of the film opposite to the heating body side. In the image forming apparatus, which is a film-type fixing device, in which the toner image-bearing recording material is closely contacted with the film, and the toner image is heated and fixed by the heat from the heating body through the film by moving and passing through the position of the heating body together with the film, The image forming method is characterized in that the driving speed of the recording medium can be switched in at least two stages apparatus.

(17) The image forming apparatus according to (16), wherein the film driving speed is controlled to be slower when the recording material is shorter than when the recording material is long.

◎ The following (18) and (19) are claims.
The invention according to 19 is a means for solving the problem (F).

(18) The image fixing device has a heating body that generates heat when energized and a film that is slidably driven on the heating body, and an image forming unit is provided on the surface of the film opposite to the heating body side. In the image forming apparatus, which is a film-type fixing device, in which the toner image-bearing recording material is closely contacted with the film, and the toner image is heated and fixed by the heat from the heating body through the film by moving and passing through the position of the heating body together with the film, The driving speed and the control temperature of the heating element can be switched in at least two stages or more, and a means for detecting the length of the recording material in the conveying direction is provided, and the driving speed of the film and the heating element An image forming apparatus characterized by switching a control temperature.

(19) The image forming apparatus described in (18) is characterized in that the shorter the recording material is, the slower the film driving speed is and the lower the control temperature of the heating member is, as compared with the long recording material.

[0055]

[Action]

Effects of the Inventions (1) to (3) After the power supply to the heating body of the fixing device is stopped, the speed of the film driven at the first speed is switched to the second speed, and then the driving of the film is stopped, that is, When the last sheet to be fixed is discharged, the heating body is de-energized and the film is driven at high speed to accelerate the cooling of the heating body. The time until the film is cooled can be shortened.

Therefore, since the time during which the film is driven after the copy is completed is short, the operator does not feel unnatural. Further, since the film is stopped after the heating element is cooled, the film is protected from thermal damage, sticking to the pressure roller, adhesion of foreign matter, damage, etc., and the problem of the above (A) is solved. To be done.

Actions of the Inventions (4) to (6) The film is driven at the first speed when the recording material is present in the fixing device, and the film is driven at the third speed when the recording material leaves the fixing device. When the recording material is introduced into the fixing device again, the film drive is switched to the first speed, that is, when the recording material does not pass through the fixing device during continuous copying. By driving the film at a low speed to the third speed during the material interval (paper interval), it is possible to reduce the amount of heat wasted by the film from the heating element, so that the film is supplied to the heating element. You can save electricity. Further, since the speed of the film driving motor is low, the load on the motor is lightened, and the problem (B) is solved.

When the recording material is introduced into the fixing device, the film is driven at the third speed from the start of the fixing device to the introduction of the recording material into the fixing device. Drive at the first speed, that is, when the apparatus is started, the film is driven at a low third speed to heat the heating body, and during the non-fixing period, the heat wasted by the heating body to the film wastefully. The emission of heat can be reduced, the rise time of the temperature of the heating element can be shortened, and the power consumption can be saved.

Further, when the film driving torque of the fixing device is large and the temperature is low, the load on the motor can be reduced by driving the film at the low third speed. In addition, since the temperature of the heating element rises quickly, even if the time from the start of the copying operation to the arrival of the recording material in the fixing device is short, it is possible to cope with the increase in the electric power supplied to the heating element. Therefore, the problem (C) is solved.

The functions of the inventions (10) to (15) have means for detecting the temperature of the heating element of the fixing device, and the temperature detected by the temperature detecting means at the start of the image forming operation of the image forming section is predetermined. When the temperature is lower than the temperature, the film is driven at the third speed, and when the recording material is introduced from the image forming unit to the fixing device, the film is switched to the first speed.
Alternatively, it has a means for measuring the time from the end of the image forming operation, and when the next image forming operation is started after measuring the time of a predetermined time or more, the film of the fixing device is moved at the third speed. When the toner image is driven to fix the toner image, the film drive is switched to the first speed, that is, when the fixing device is completely cooled after a certain time has elapsed from the end of the previous copying, Since the film of the fixing device is driven at the low speed of the third speed at the start of copying,
The amount of heat that escapes from the heating element to the film decreases, and the temperature rises faster.

Further, when the fixing device is cold and the viscosity of the lubricant interposed between the heating body and the film is large and the driving torque is large and the temperature is low, the film is driven at a low third speed. Since this is done, the burden on the motor, gears, etc. can be reduced, and the problem (D) can be solved.

The operation of the inventions (16) and (17): The driving speed of the film can be switched in at least two steps or more, and means for detecting the length of the recording material used in the conveying direction is provided. The film drive speed can be varied by changing the film drive speed, that is, by detecting the length of the recording material and switching the film drive speed of the fixing device according to the length, the time when the recording material does not exist in the fixing device can be shortened. Therefore, the electric power supplied to the fixing device can be effectively used.

Further, when fixing the same number of sheets, the number of times of sliding of the film on the heating element of the fixing device is smaller than that of driving the film of the fixing device at a constant speed, so that damage to the film can be reduced. it can. Also, when the recording material is small and thick such as postcards and business cards, the drive speed of the film is slow, so the temperature stability during fixing is increased and fixing failure does not occur. The above problem (E) is solved.

Actions of the Inventions (18) and (19) The drive speed of the film and the control temperature of the heating element can be switched in at least two stages, and means for detecting the length of the recording material used in the transport direction is provided. By switching the drive speed of the film and the control temperature of the heating element according to the length of the recording material, that is, by detecting the length of the recording material and switching the drive speed of the film of the fixing device according to the length, Since the time when the recording material does not exist in the fixing device can be shortened, the electric power supplied to the fixing device can be effectively used.

Further, when fixing the same number of sheets, the number of times the film slides on the heating element of the film is smaller than when the film is driven at a constant speed, so that damage to the film can be reduced.

When the recording material is small, the fixing temperature is low, so that the heat damage given to the film can be reduced.

Further, when a recording material having a small size and a large thickness such as a postcard or a business card is used, the driving speed of the film is low, so that the stability of the temperature at the time of fixing is increased and the fixing failure does not occur. Therefore, the problem (E) is solved.

[0068]

【Example】

<Example 1> (Figs. 1 to 10) The present example and the following Example 2 are examples of the invention described in claims 1 to 3. That is, this is an embodiment of the invention characterized in that after the power supply to the heating body of the fixing device is stopped, the speed of the film being driven at the first speed is switched to the second speed, and then the driving of the film is stopped.

(1) Schematic Structure of Image Forming Apparatus (FIG. 1) The image forming apparatus of the present embodiment is a reciprocating platen type / rotating drum type / transfer type electrophotographic copying apparatus.

Reference numeral 100 denotes an apparatus casing, and 1 denotes a reciprocating type manuscript table (manuscript placing table) made of a transparent plate member such as a glass plate disposed on an upper surface plate 100a of the apparatus machine. The face plate 100a is driven to reciprocate to the right a and the left a'in the drawing at a predetermined speed.

Reference numeral G denotes an original document, which is placed on the upper surface of the original document table 1 with the image surface side to be copied facing downward in accordance with a predetermined placement standard, and the original document pressure plate 1a is placed on the original document platen 1a to set it. To be done.

Reference numeral 100b denotes a direction perpendicular to the reciprocating direction of the document table 1 on the surface of the machine top plate 100a (direction perpendicular to the paper surface).
Is a slit opening serving as a document illuminating part having a long side.

The downward image surface of the document G set on the document table 1 sequentially passes through the position of the slit opening 100b from the right side to the left side in the forward movement process of the document table 1 to the right a. In the course of the passage, the light L of the lamp 3 is received through the slit opening 100b and the transparent document table 1 and is illuminated and scanned. The light reflected from the document surface of the illumination scanning light is image-wise exposed on the surface of the photosensitive drum 4 by the short-focus small-diameter image-forming element array 2.

The photosensitive drum 4 is coated with a photosensitive layer such as a zinc oxide photosensitive layer or an organic semiconductor photosensitive layer, and the central support shaft 4
It is rotationally driven in the clockwise direction indicated by an arrow b at a predetermined peripheral speed around a, and in the course of the rotation, it is subjected to uniform charging treatment of positive polarity or negative polarity by the charger 5, and the uniformly charged surface is subjected to the above-mentioned By receiving the image formation exposure (slit exposure) of the document image, an electrostatic latent image corresponding to the image-formed exposure document image is sequentially formed on the surface of the photosensitive drum 4.

This electrostatic latent image is sequentially visualized by a developing device 6 with toner made of resin or the like which is softened and melted by heating,
The toner image, which is the visible image, moves to a portion where the transfer discharger 9 as a transfer portion is provided.

Reference numeral S denotes a cassette in which recording materials (transfer materials) P are stacked and accommodated. The recording materials P in the cassette are fed out and fed one by one by the rotation of the feeding roller 7, and then the registration roller 8 causes the drum to move. When the tip of the toner image forming portion on 4 reaches the portion of the transfer discharger 9, the tip of the recording material P also arrives at the position between the transfer discharger 9 and the photosensitive drum 4, and the timing is adjusted so that they coincide with each other. It is then delivered synchronously. Then, the toner image on the side of the photosensitive drum 4 is sequentially transferred by the transfer discharger 9 onto the surface of the fed recording material.

The recording material, to which the toner image has been transferred at the transfer portion, is sequentially separated from the surface of the photosensitive drum 4 by separating means (not shown), and is conveyed by the conveying device 10 to the film-type fixing device 1 described later.
The unfixed toner image carried to the sheet 1 is subjected to heat fixing processing, and is discharged as an image-formed product (copy) through the guide 43 and the discharge roller 44 onto the discharge tray 12 outside the apparatus.

The surface of the photosensitive drum 4 after the image transfer is subjected to removal of adhered contaminants such as transfer residual toner by the cleaning device 13 and is repeatedly used for image formation.

(2) Structure of the fixing device 11 (FIGS. 2 and 3) 18 is an endless belt-shaped fixing film, and includes a left driving roller 19, a right driven roller 20 and a space between the rollers 19 and 20. Low heat capacity linear heating element 14 as a heating element (heater) fixedly supported below
And a guide roller 19a disposed below the drive roller 19 are stretched between the four members which are parallel to each other.

The driven roller 20 also serves as a tension roller for the film 18, and the film 18 is rotated at a predetermined peripheral speed in the clockwise direction with the clockwise rotation of the driving roller 19, that is, the image forming section (image transfer section 9, FIG. The recording material P having an unfixed toner image Ta conveyed from the side 1) on its upper surface.
It is driven to rotate without wrinkling, meandering, or speed delay at the same peripheral speed as the transport speed of.

Reference numeral 21 is a pressure roller as a pressure member having a rubber elastic layer having a good releasability such as silicon rubber, and is placed on the lower surface of the heating body 14 with the lower film portion of the film 18 interposed therebetween. For example, a total pressure of 4
The recording material P is brought into counter pressure contact with a contact pressure of ˜7 kg, and rotates in the forward counterclockwise direction in the transport direction of the recording material P.

Since the film 18 which is rotationally driven is repeatedly used for heat fixing of the toner image, heat resistance, releasability,
A thin film having excellent durability and generally having a total thickness of 100 μm or less, preferably less than 40 μm is used.

For example, polyimide / polyetherimide /
A single layer film of a heat-resistant resin such as PES / PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin) or a composite layer film, for example, a 20 μm thick film, is provided with PTFE (tetrafluoroethylene) at least on the image contact surface side. (Resin) -PAF or other fluororesin with a conductive material added thereto and a release coating layer having a thickness of 10 μm.

The low-heat-capacity linear heating element 14 of this example has a laterally long, high heat resistance, high thermal conductivity, and a longitudinal direction in the transverse direction of the film (direction perpendicular to the running direction of the film 18).
Insulating heater substrate 15 and energization heating resistor (heating element)
16 and a temperature detecting element 17 as a means for detecting the temperature of the heating body 14, and the like.
The side surface faces downward, and is attached and supported by a heater holder 14A having rigidity, high heat resistance, and heat insulation.

The heater holder 14A is for holding the heating body 14 in adiabatic manner with respect to the fixing device and the image forming device, and for example, PPS (polyphenylene sulfide), PAI (polyamide imide), PI (polyimide), PEEK (polyether ether ketone). , A high heat resistant resin such as liquid crystal polymer, or a composite material of these resins and ceramic metal, glass or the like.

The heater substrate 15 is 1.0 m thick as an example.
It is an alumina substrate with m, width 6.0 mm and length 240 mm. Alternatively, it is a composite material substrate or the like.

[0087] the heating element 16 along the longitudinal substantially central portion of the lower surface of the substrate 15, for example _{Ag / Pd, RuO 2, Ta} 2 N
It is a linear or strip-shaped low-heat-capacity electric heating element provided by coating (screen printing, etc.) an electric resistance material such as the above with a width of 1.0 mm.

A heat-resistant fluorine-based grease or the like is applied as a lubricant to the surface of the heating element 14 on the side of the heating element 16 which is the film sliding surface in order to reduce the frictional friction resistance with the film 18. I am doing it.

The temperature detecting element 17 is the upper surface of the substrate 15 (the heating element 1).
It is a resistance temperature detector having a low heat capacity such as a thermistor and a Pt film provided on the surface opposite to the side on which 6 is provided. In this example, the temperature of the substrate 15 is set as the temperature of the heating body 14 and the temperature detecting element 17 is used.
Is detected by.

By energizing both longitudinal ends of the heating element 16, the heating element 16 generates heat and the temperature of the heating element 14 rises. Heating element 1
The electric power supplied to 6 is controlled by the output of the temperature detecting element 17 of the heating element 14, and the heating element 14 is controlled to a predetermined temperature.

As described above, the film 18 is slidably moved in contact with the temperature-controlled heating body 14, and the pressure contact portion N (fixing nip portion) between the temperature-controlled heating body 14 and the pressure roller 21 is fixed. The recording material P enters between the film 18 and the pressure roller 21, and the unfixed toner image surface of the recording material P moves in the same direction as the conveyance speed of the recording material P in the fixing film 18 in the surface movement state in the same direction. While passing through the fixing nip portion N between the heating body 14 and the pressure roller 21 while being pressed and overlapped with the fixing film 17, the fixing nip portion N is closely contacted with the lower surface without causing surface deviation or wrinkling, In the course of the passage, the heat of the heating body 14 is received through the film 18, and the toner image Ta is melted at a high temperature and softened and adhered to the surface of the recording material P, Tb.

In the case of the apparatus of this example, the recording material P and the film 18
Separation from the recording material P is performed when the recording material P passes through the fixing nip portion N and exits. While the recording material P separated from the film 18 is guided by the guide 43 and reaches the discharge roller pair (44), the temperature of the toner Tb, which is higher than the glass transition point, is naturally lowered (natural cooling) and is equal to or lower than the glass transition point. When the temperature reaches the solidification temperature Tc, the recording material (copy) on which the image is fixed is output onto the tray.

The fixing film 18 is not limited to the endless belt shape, and the endless fixing film 18 wound around the delivery shaft 41 as shown in FIG. 3 is wound between the heating body 14 and the pressure roller 21 and the guide roller. It may be configured such that it is engaged with the take-up shaft 42 via the underside of 19a and travels from the delivery shaft 41 side to the take-up shaft 42 side at the same speed as the conveyance speed of the recording material P.

The pressure roller 21 may also be used as a driving means for the film 18, and the film 18 may be rotated or driven by the rotational driving force of the pressure roller 21.

(3) Control A. Configuration of Control Circuit (FIGS. 4 and 5) FIG. 4 is a block diagram of a control unit of the image forming apparatus.

Reference numeral 101 is a control circuit, which is composed of a microcomputer or the like. Reference numeral 102 denotes a ROM, which stores control software executed by the control circuit 101 and control data. A RAM 103 is a writable storage unit used for control.

Reference numeral 104 is a position sensor (original sensor) of the reciprocating type document table 1, 105 is a paper feed sensor for detecting the presence of the recording material P in the paper feeding section, and 106 is the recording material P passing through the fixing device 11. A paper discharge sensor for detecting that the paper has been discharged, and a pre-fixing sensor 112 for detecting that the recording material P has arrived just before the fixing device 11.

Each of these sensors 104 to 106.11
Reference numeral 2 is composed of a photo interrupter and a flag (shield), and when the photo interrupter detects the flag, the signals thereof are input ports PO, PC, E of the control circuit 101, respectively.
Input to X and PTC, the input port changes from low level 0 to high level 1.

Reference numeral 107 denotes a main motor of the image forming apparatus,
M is a drive signal output port of the control circuit 101 for the motor 107.

Reference numeral 111 is a film motor (film drive motor) of the fixing device 11, and FM is a drive signal output port of the control circuit 101 for this motor. From the control circuit 101 to the motor 111: a, a first speed that is a normal speed when performing image fixing, b, a second speed that is faster than the first speed, c, a third speed that is slower than the first speed , And three drive signals are selectively output.

This is the same in all the embodiments described later.

Reference numeral 108 denotes a cooling fan drive motor, F
The AN is a control circuit 10 for the fan motor 108.
1 is a drive signal output port.

The main motor 107 is used for driving the load of the fixing device 11 other than driving the film and cooling fan.

Reference numeral 109 denotes a power supply power source (fixing power source) for the heating element 16 of the heating element 14 of the fixing device 11. The power source 109 supplies power to the heating element 16 of the heating element 14 to supply the heating element 14 Heats up.

The temperature of the heating element 14 is detected by the thermistor (temperature detecting element) 17, and the temperature information is input to the control circuit 101. Based on the temperature information, the output port TC of the control circuit 101 supplies the fixing power supply 109. The control signal is output,
Electric power controlled by the power source 109 is supplied to the heating element 16 to control the heating element 14 to a predetermined temperature.

Reference numeral 110 denotes an operation unit, which is connected to the control circuit 101 and used by the operator for key input and display. Figure 5
Is a plan view of the operation unit 110.

Reference numeral 118 is a JAM lamp and 117 is a 7-segment display section for displaying an error or a jam display together with a jam lamp, and for 7-segment setting of the number of sheets with operation keys.

Reference numerals 113 to 116 denote operation keys, which are 11
3 is a copy key, 114 is a clear key, 115 is a plus key, and 116 is an AE key. Reference numeral 120 denotes an AE lamp, which displays an AE operation.

B. Operation of control circuit. The operation from when the copy key 113 is NO until the film motor 111 reaches the regular first speed when performing image fixing (FIGS. 6 and 7).

FIGS. 6 and 7 are a timing chart and a control flow chart during this operation period. In the timing chart of FIG. 6, the copy key 113 is executed at timing T1.
At the same time when is turned on, the main motor 107 starts driving. Then, at a timing T2 after a lapse of a certain period of time, energization of the heating element 14 to the heating element 16 is started, and at the same time, the film motor 111 is driven. At this time, the drive signal output from the output port FM of the control circuit 101 is It is a signal (third speed signal) for driving the film motor 111 at a low speed (in the figure, the level indicating the timing is low, but this indicates that the motor 111 is driven at a low speed).

The timing T2 may be determined so that the heating body 14 reaches a predetermined temperature (fixing temperature) by the time the recording material P enters the fixing device 11. For example, after the copy key 113 is turned on. May be measured, or an existing signal (paper feed sensor 105, paper discharge sensor 106, etc.) may be used to measure the time since the input. If the copy speed is fast, this time should be short, and if the copy speed is slow, it should be long.

When the pre-fixing sensor 112 detects that the recording material P paper has arrived after a further time (timing T
3), a control signal (first speed signal) is output from the output port FM of the control circuit 101 to the motor 11 so that the film motor 111 has a regular first speed when performing image fixing.
It is output to 1.

In the flowchart of FIG. 7 (# indicates a step number), when the copy key 113 is turned on in # 1, the main motor 107 is turned on in # 2.

Wait for timing T2 at # 3 (W
AIT), and when timing T2 arrives, the heating element 16 starts at # 4.
Heating of the heating body 14 is started by energizing the film motor 111, and at the same time, the film motor 111 is driven at a low speed (third speed).

In # 5, WAIT is performed until the paper reaches the pre-fixing sensor 112, and when the pre-fixing sensor 112 detects the recording material P, the temperature of the heating element 14 is checked in # 6. If there is no abnormality in temperature, # At 8, the film motor 111 is driven at the regular first speed to perform the fixing operation. If the temperature is abnormal, error processing is performed in # 7.

.. A film driving operation when the recording material P does not pass through the fixing device 111 during continuous copying, that is, between recording materials (paper interval) (FIGS. 8 and 9).

In the timing chart of FIG. 8, when at least one of the pre-fixing sensor 112 and the paper discharge sensor 106 detects the presence of the recording material P, that is, when there is a recording material in the fixing execution state or immediately before the fixing state. The film motor 111 is driven at the normal first speed.

On the other hand, when both the pre-fixing sensor 112 and the paper discharge sensor 106 are not detecting the recording material, that is, when there is no recording material in the fixing execution state or immediately before the fixing state, the film motor 111 is set to the third speed. Drive at low speed.

In the flowchart of FIG. 9, it is checked at # 1 whether the pre-fixing sensor 112 and the paper discharge sensor 106 are both in a paper-free state. If either one of the recording materials is detected, the process returns to the main routine, and if neither detects the presence of the recording material, the film motor 111 is switched to the low speed driving of the third speed in # 2.

In # 3, WAIT is performed until the recording material reaches the pre-fixing sensor 112, and when the pre-fixing sensor 112 detects the recording material, the film motor 111 is driven at the normal first speed in # 4.

.. Operation at the end of copy operation (FIG. 10) FIG. 10 is a flowchart at the end of copy operation.

At # 1, it is determined whether the recording material currently being copied is the last one. The determination method may be a counter value that is subtracted from the number of sheets set by the user, or any method such as the fact that the paper feed sensor 105 detects the absence of recording material at a certain timing may be used.

When it is determined that the last sheet is the one in # 1,
In # 2, WAIT is performed until the discharge sensor 106 detects that the recording material has come out of the fixing device 11, and in # 3, the heating element 14
The heating of the heating element 16 of the
1 is driven at a high second speed.

Then, if the temperature of the heating element detected by the thermistor 17 in contact with the heating element 14 at # 4 drops to a certain set temperature, the film motor 111 is stopped at # 5 and the copying operation is completed.

As described above, when the last one sheet is discharged, the power supply to the heating element 16 of the heating element 14 is stopped and the film motor 111 is driven at the high speed second speed. Since the cooling is accelerated, the time until the film 18 is cooled can be shortened.

Therefore, after the copying is completed, the film 18
The operating time is short, so the operator does not feel unnatural.

After cooling the heating element 14, the film 18
Since the driving of the film is stopped, the film is protected from thermal damage, sticking to the pressure roller 21, adhesion of foreign matter, damage and the like.

<Embodiment 2> (FIGS. 11 and 12) This embodiment is another control example of the operation at the end of the copying operation of (3) -B- in Embodiment 1 described above.

FIG. 11 is a timing chart at the end of copying.

The last recording material passes through the fixing device 11,
When the discharge sensor 106 becomes 0 level, driving of the main motor 107 and energization of the heating element 16 of the heating element 14 are stopped. At that time, the drive speed of the film motor 111 is switched to the second speed which is a high speed, and stops after the time t has elapsed. The time t is set in advance until the temperature of the heating element 14 drops to a predetermined temperature.

In the flowchart at the end of copying in FIG. 12, it is judged at # 1 whether the recording material being currently copied is the last one.
Wait until F.

When the paper discharge sensor 106 is turned off, # 3
The main motor 107 is stopped at, the power supply to the heating element 16 of the heating element 14 is stopped at # 4, and the film motor 111
Is switched to the high speed second speed.

Then, the measurement of the time t is started at # 5. This time t is set to the time until the temperature of the heating element 14 drops to a predetermined temperature.

At # 6, the time t is awaited, and when the time t has elapsed, the film motor 111 is stopped.

The rest of the apparatus configuration and control are the same as those in the first embodiment, and the repetitive description will be omitted. In the case of this embodiment, the same operational effect as that of the first embodiment is obtained.

<Embodiment 3> (FIGS. 1 to 10) This embodiment and the next embodiment 4 are embodiments of the invention described in claims 4 to 6. That is, it is an embodiment of the invention regarding drive control of a film between sheets.

In the first embodiment, (1) the overall schematic structure of the image forming apparatus (FIG. 1), (2) the structure of the fixing device (FIGS. 2 and 3), and (3) control (FIG. 4 to 10) are the same in this embodiment.

Thus, (3) -B- (FIG. 8) of the first embodiment.
As described in FIG. 9), the fixing device 1 is in continuous copying.
When the recording material P does not pass through 1, that is, when the recording material is between the recording materials (paper interval), the film is driven from the heating body 14 to the film 18 by setting the low speed to the third speed. Since the amount of heat released to the heating element 14 can be reduced, the power supplied to the heating element 14 can be saved. In addition, since the speed of the film driving motor 111 is low, the load on the motor 111 is lightened. <Fourth Embodiment> (FIGS. 13 to 15) FIG. 13 is a block diagram of a control unit according to the present embodiment. The control unit of the present example has a configuration in which the pre-fixing sensor 112 is removed from the control unit of FIG. 4 described above, and is otherwise the same.

FIGS. 14 and 15 show the film driving in the present embodiment when the recording material P is not passing through the fixing device 11 during continuous copying, that is, between the recording materials (paper interval). It is a timing chart and a flow chart of operation.

In the timing chart of FIG. 14, when the paper discharge sensor 106 is turned on, a counter (not shown) in the control circuit 101 starts measuring the time t.

At this time t, the discharge sensor 106 is turned on.
It is the time from when the next recording material comes to the front of the fixing device 11 and is constant regardless of the size of the recording material P.

When the paper discharge sensor 106 is turned off, the film motor 111 is switched to the low speed driving of the third speed.

When the time t has elapsed, the speed of the film motor 111 is switched to the regular first speed.

In the flowchart of FIG. 15, whether or not the recording material has passed through the paper discharge sensor 106 is detected in # 1, and when the recording material is removed, the drive of the film motor 111 is switched to the second speed which is a low speed in # 2.

Waiting for the time t described above to pass in # 3, when the time t passes, the drive of the film motor 111 is switched to the regular first speed in # 4 to fix the toner image.

The other device configuration and control are the same as in the first embodiment. This embodiment also has the same effects as the above-mentioned third embodiment.

<Embodiment 5> (FIGS. 1 to 10) This embodiment and the next embodiment 6 are embodiments of the invention described in claims 7 to 9. That is, it is an embodiment of the invention about the film driving at the time of starting the fixing device.

In the first embodiment, (1) the overall schematic structure of the image forming apparatus (FIG. 1), (2) the structure of the fixing device (2. FIG. 3), and (3) control (FIG. 4). (FIG. 10) is the same in this embodiment.

Then, (3) -B- in FIG.
As described with reference to FIG. 7), the heating element 1 of the heating element 14 from when the copy key 113 is turned on to when the film motor 111 reaches the regular first speed when performing image fixing.
6 does not energize the heating element 16 of the heating element 14 immediately after the start of the copying operation, and the film 18 is driven.
At the time of starting, the film is rotated at a low third speed to heat the heating body 14.

Therefore, during the non-fixing period, it is possible to reduce the heat released from the heating body 14 to the film 18 in vain, so that the rise time of the heating body temperature can be shortened and the power consumption can be saved.

Further, since the film 18 is driven at the low third speed when the film driving torque of the fixing device 11 is large and the temperature is low, the load on the motor 111 can be reduced.

Further, since the heating member temperature rises quickly, even if the time from the start of the copying operation until the recording material arrives at the fixing device 11 is short, the power supplied to the heating member 14 is not increased. Can respond.

<Sixth Embodiment> (FIGS. 16 to 18) FIG. 16 is a block diagram of a control unit of the present embodiment. The control unit of this example has a configuration in which an FMON sensor 121 is added to the control unit of FIG. 4 described above, and is otherwise the same.

The FMON sensor 121 is a sensor for detecting the timing of starting the driving of the film motor 111, and the recording material P passes through the paper feeding portion and the fixing device 1
The recording medium P is installed by the time of entering 1, and when the recording material P passes through the sensor portion, the input port PF of the control circuit 101 becomes high level 1.

FIGS. 17 and 18 are timing charts and a flow chart of the film driving from the turning on of the copy key 113 to the regular first speed when the film motor 111 executes the image fixing in this embodiment. is there.

In the timing chart of FIG. 17, when the recording material P is fed and passes through the FMON sensor 121 (timing T1), the input port PF becomes high level. At this time, the film motor 111 is operated at the low speed second speed.
Driving at a speed is started, and at the same time, energization of the heating element 14 of the heating element 14 is started.

When the recording material reaches the pre-fixing sensor 112 (timing T2), the input port PTC becomes high level, at which time the speed of the film motor 111 is switched to the normal first speed, and the toner image is heated. It is fixed.

In the flowchart of FIG. 18, when the copy key 113 is turned on in # 1, the main motor 107 is driven in # 2.

In # 3, WAIT is performed until the FMON sensor 121 detects the passage of the recording material, and when detected, in # 4, the low speed driving of the film motor 111 at the second speed is started, and the heating element 16 of the heating element 14 is started. Energize to.

At # 5, WAIT is performed until the recording material arrives at the pre-fixing sensor 112, and at # 6, whether or not the temperature of the heating body 14 is within a predetermined range is chucked. If it is within the predetermined range, the drive of the film motor 111 is switched to the regular first speed in # 8 and fixing is performed.

The other device configuration and control are the same as in the first embodiment. This embodiment also has the same operation and effect as the above-mentioned fifth embodiment.

<Embodiment 7> (FIG. 19) This embodiment to Embodiment 9 are embodiments of the invention described in claims 10 to 12. That is, the temperature state of the heating body 14 at the time of starting the film (at the start of the copying operation) (= the temperature state of the lubricant (heat-resistant fluorine-based grease) interposed between the heating body 14 and the film 18), that is, It is an Example about the invention which controls the film drive at the time of starting the film in relation to the viscosity state.

The general schematic structure of the image forming apparatus (1) of the first embodiment (FIG. 1) and the structure of the fixing device (2) (FIGS. 2 and 3) of the first embodiment are the same in this embodiment. ..

The control system is also almost the same as that of the first embodiment, but in the present embodiment, the thermistor 17 of the heating body 14 also serves as a means for detecting the temperature of the heating body 14 at the start of the copying operation, and the copying operation is started. At times, the temperature of the heating element 14 is detected by the thermistor 17, and if the temperature is lower than a certain temperature, the film 18 is controlled so as to be activated at a second speed which is a low speed.

FIG. 19 is a flowchart from when the copy key 113 is turned on to when fixing is started.

When the copy key 113 is turned on in # 1,
The main motor 107 is driven in # 2. In # 3, it is checked whether the temperature T of the heating element 14 is lower than a predetermined temperature T1. If not, in # 6, the film motor 111 is set to a normal speed for image fixing.
Driving at speed, fixing is performed as it is.

When it is detected that T is lower than T1 in # 3, the film motor 111 is set to the low speed second speed in # 4.
It is driven at a speed, and at the same time, energization of the heating element 14 of the heating element 14 is started.

Next, in # 5, the pre-fixing sensor 112 waits until the recording material P is detected to be in front of the fixing device 11. Then, in # 6, the drive speed of the film motor 111 is switched to the regular first speed, Fix it.

By controlling in this manner, when the fixing device is completely cooled after a certain time has elapsed since the end of the previous copy, the film 18 of the fixing device 11 is driven at the start of the next copy. Is performed at a low third speed, the amount of heat escaping from the heating body 14 to the film is reduced, and the temperature rises quickly.

Further, when the fixing device is cold and the viscosity of the lubricant interposed between the heating body 14 and the film 18 is large and the driving torque is large, the film 18 is driven at a low speed at a low speed. Since the operation is performed at two speeds, the load on the motor 111 and gears is reduced.

<Embodiment 8> (FIGS. 20 and 21) This embodiment is another control example of Embodiment 7.

FIG. 20 is a block diagram of the control unit of this embodiment. The control unit of the present example has a configuration in which the pre-fixing sensor 112 is removed from the control unit of FIG. 4 described above, and is otherwise the same.

However, a timer is built in the control circuit 101 to count a time T2 which is shorter than the time required for the recording material P to reach the fixing device 11, and the speed of the film motor 111 is determined by the end of the counting. Switch.

In the flowchart of FIG. 21, when the copy key 113 is turned on in # 1, the main motor 107 is driven in # 2.

At # 3, the temperature of the heating element 14 is checked. If the temperature is T1 or higher, at # 8, the film motor 111 is driven at the regular first speed for image fixing, and fixing is performed as it is.

When it is detected in # 3 that the temperature of the heating element 14 is T1 or lower, the film motor 111 is driven at a low third speed in # 4, and at the same time, the heating element 16 of the heating element 14 is transferred to the heating element 16. Energization also starts.

Then, in # 5, the timer value inside the control circuit is set to t2, and in # 6 and # 7, it is counted until the timer value becomes 0. When the counting is completed, the film motor 111 is switched to the first speed at # 8 and fixing is performed.

The other device configuration and control are the same as in the first embodiment. This embodiment also has the same effects as the above-described seventh embodiment.

<Ninth Embodiment> (FIGS. 22 and 23) This embodiment is still another control example of the seventh embodiment.

FIG. 22 is a block diagram of the control unit of the present embodiment, which is similar to the control unit of the eighth embodiment (FIG. 20), but the control unit of the present embodiment does not include a timer.

In the flowchart of FIG. 23, when the copy key 113 is turned on in # 1, the main motor 107 is activated in # 2.

At # 3, the temperature of the heating element 14 is chucked, and T
If the temperature is higher than 1, film motor 11 with # 6
1 is driven at the regular first speed for image fixing, and fixing is performed as it is.

On the other hand, if the temperature of the heating element 14 is lower than T1 in # 3, the film motor 111 is driven at the low third speed in # 4, and the temperature of the heating element 14 becomes higher than T1 in # 5. When it becomes high, the driving speed of the film motor 111 is switched to the second speed which is a low speed and fixing is performed at # 6.

Other device configurations and controls are the same as in the first embodiment. This embodiment also has the same effects as the above-described seventh embodiment.

<Embodiment 10> (FIGS. 24 and 25) This embodiment and the following Embodiment 11 are embodiments of the invention described in claims 13 to 15. That is, it is an embodiment of the invention for controlling the film drive at the time of starting the film in relation to the leaving time of the apparatus until the start of the film (start of the copying operation).

The general schematic structure of the image forming apparatus (1) of the first embodiment (FIG. 1) and the structure of the fixing device (2) (FIGS. 2 and 3) of the first embodiment are the same in this embodiment. ..

The control system is almost the same as that of the first embodiment, but in this embodiment the control unit has a timer 122 as shown in FIG. Other configurations of the control unit are the same as those in FIG.

The timer 122 is reset by the input of a signal from the control circuit 101 to the terminal R at the end of copying, the timer value is started, and a certain time T
Until 1 has passed, a high level “1” signal is output to the input port TI of the control circuit 101.

The timer 122 is configured to operate even when the power switch of the image forming apparatus main body is not turned on, and the time measurement after the end of the copying operation is continued even when the power switch is off.

In the flowchart of FIG. 25, when the copy key 113 is turned on in # 1, the main motor 107 is driven in # 2.

Next, at # 3, it is checked whether or not time T1 or more has elapsed since the last copy was completed.

If the elapsed time from the end of the previous copying is within T1, the film motor 111 is driven at the regular first speed for image fixing, and when the recording material P reaches the fixing device 11, the fixing is performed as it is.

When the time T1 or more has elapsed from the end of the previous copying in # 3, the film motor 111 is driven at the low speed third speed in # 4, and at the same time, the heating element 1 of the heating element 14 is driven.
6 is energized to start heating the heating element 14.

Next, in # 5, the pre-fixing sensor 112 waits until the recording material P is detected to be in front of the fixing device 11. Then, in # 6, the driving speed of the film motor 111 is set to the normal speed for image fixing. Fixing is performed by switching to the first speed.

The timer 122 in this embodiment may be a simple one that merely uses the discharge of the capacitor. Further, a method of counting inside the control circuit 101 may be used without providing the timer 122 independently of the control circuit 101 as in the present embodiment.

By controlling in this way, when the fixing device 11 is completely cooled after a lapse of a certain amount of time from the end of the previous copy, the film 18 of the fixing device 11 at the beginning of the next copy is started. Since the driving is performed at the low third speed, the amount of heat escaping from the heating body 14 to the film 18 is reduced, and the temperature rises faster.

When the fixing device is cold and the viscosity of the lubricant interposed between the heating body 14 and the film 18 is high and the driving torque is large, the film 18 is driven at a low speed at a low speed. Since it is performed at 3 speeds, motor 1
The burden on 11 and gears is also reduced.

<Embodiment 11> (FIGS. 26 and 27) This embodiment is another control example of the tenth embodiment.

FIG. 26 is a block diagram of the control unit of this embodiment. The control unit of this example is the same as the control unit of the tenth embodiment (see FIG.
The configuration is the same as that in 4) except that the pre-fixing sensor 112 is removed, and the others are the same.

However, a timer is built in the control circuit 101 to count a time T2 shorter than the time required for the recording material P to reach the fixing device 11, and the speed of the film motor 111 is determined by the end of the counting. Switch.

In the flowchart of FIG. 27, when the copy key 113 is turned on in # 1, the main motor 107 is driven in # 2.

At # 3, it is checked whether or not a time T1 or more has elapsed from the end of the previous copy. The passage of time is T
If it is less than 1, the film motor 111 is driven at the regular first speed for image fixing in # 6, and at the same time, energization of the heating element 16 of the heating element 14 is started and fixing is performed as it is.

If the time T1 or more has elapsed from the end of the previous copying in # 3, the film motor 111 is driven at a low third speed in # 4, and at the same time, the heating element 1 of the heating element 14 is driven.
Energization of 6 is started.

Next, in # 5, the timer value in the control circuit 101 is set to T2, and in # 6 and # 7, counting is performed until the timer value becomes 0. When the counting is completed, in # 8, the film motor 111 is turned on. The driving speed is switched to the regular first speed for image fixing, and fixing is performed.

The other device configuration and control are the same as in the first embodiment. This embodiment also has the same effects as those of the tenth embodiment.

<Embodiment 12> (FIGS. 28 and 29) This embodiment and the next embodiment 13 are embodiments of the invention described in claims 16 and 17. That is, this is an embodiment of the invention for controlling the film drive in relation to the length of the used recording material P in the transport direction.

The general schematic structure of the image forming apparatus (1) (FIG. 1) and the structure of the fixing device (2) (FIGS. 2 and 3) in the first embodiment are the same in this embodiment. is there.

The control system is also substantially the same as that in the first embodiment, but in this embodiment, when the length of the recording material P used is longer than the predetermined length l, the film 18 is driven during fixing. When the speed is less than l, the fixing is performed at the third speed, which is slower than the first speed. The length l here needs to be set to a length shorter than the length of the sheet path between the fixing device 11 and the developing device 6 in FIG.

FIG. 28 is a timing chart from the detection of the recording material P by the paper feed sensor 105 to the fixing of the recording material P. FIG. 28 (a) shows that when the length of the recording material P is longer than l.
(B) is a chart when it is shorter than l. FIG. 30 is a flowchart thereof.

The timing chart of FIG. 28 is a timing chart after the copy key 113 is turned on.

The film motor 111 is initially driven at the third speed. When the recording material P enters the paper feeding section, the paper feeding sensor 105 detects the presence of the recording material P (timing T1), and the time t is counted from this point.

Here, the time t is the time required for the recording material P having the length 1 to pass through the paper feeding section, and is stored in the control circuit 101 in advance.

At the end of counting t (timing T2), the output of the paper feed sensor 105 is checked again. If the paper feed sensor 105 still detects the presence of the recording material P at this time, (a) in FIG. As described above, when the pre-fixing sensor 112 detects the arrival of the recording material P (timing T3), the drive speed of the film motor 111 is switched to the first speed.

If the paper feed sensor 105 does not detect the presence of the recording material P at the timing T2 as shown in FIG. 28B, the film motor 111 is driven at the timing T3. Fix at 3 speeds.

In the flowchart of FIG. 29, first,
In # 1, it is detected whether or not the recording material P arrives at the paper feed section, and when the recording material P arrives, the time t is measured in # 2.

After the lapse of time t, it is checked in # 3 whether or not there is the recording material P in the paper feeding section, and if not, the fixing is performed at the same speed. Waiting for P to arrive, the drive speed of the film motor is switched to the first speed in # 5.

As described above, by detecting the length of the recording material P and switching the drive speed of the film 18 of the fixing device 11 according to the length, the time when the recording material P does not exist in the fixing device 11 is detected. Therefore, the electric power supplied to the fixing device can be effectively used.

In the case of fixing the same number of sheets, rather than driving the film 18 of the fixing device 11 at a constant speed,
Since the number of times the film 18 slides on the heating body 14 or the like is small, damage to the film 18 can be reduced.

Further, when a recording material having a small size and a large thickness such as a postcard or a business card is used, the driving speed of the film 18 is slow, so that the temperature stability at the time of fixing is increased and the fixing failure occurs. Disappear.

<Embodiment 13> (FIGS. 30 to 32) This embodiment is another control example of the twelfth embodiment.

FIG. 30 is a block diagram of the control unit of this embodiment. The control unit of the present example has a length sensor 12 for detecting the length of the recording material P in addition to the control unit of the first embodiment (FIG. 4).
3 has the same structure as the others.

The length sensor 123 is the paper feed sensor 105.
It is installed at a position of the seat path portion at a distance of 1 from. The distance l here is the same as the length l of the twelfth embodiment.

FIG. 31 is a timing chart from the detection of the recording material P by the paper feed sensor 105 to the fixing of the recording material P. FIG. 31A shows a case where the length of the recording material P is longer than l.
(B) is a chart when it is shorter than l. FIG. 32 is a flowchart at this time.

In the timing chart of FIG. 31, if the length sensor 123 detects the presence of the recording material P at the timing T2 after the recording material P arrives at the sheet feeding portion (timing T1), the pre-fixing sensor 112 detects it. After waiting for the recording material P to arrive, the drive speed of the film motor 111 is switched to the first speed.

When the length sensor 123 detects the recording material P, if the recording material P is not present in the paper feed sensor 105 as shown in (b), the speed of the film motor 111 becomes the third speed.
Fix at the same speed.

In the flow chart of FIG. 32, when it is detected that the recording material P has arrived at the paper feed section in # 1, it waits for the recording material P to arrive at the length sensor 123 in # 2, and when it arrives, it is supplied in # 3. It is checked whether or not the recording material P is still present on the paper portion, and if not, the fixing is performed at the third speed.

When the presence of the recording material P is detected in # 3, # 4
Then, waiting for the recording material P to arrive at the pre-fixing sensor 112, the drive speed of the film motor 111 is switched to the first speed in # 5.

Other device configurations and controls are the same as in the first embodiment. This embodiment also has the same operation and effect as the above-mentioned twelfth embodiment.

<Embodiment 14> (FIGS. 33 to 35) This embodiment and the next embodiment 15 are embodiments of the invention described in claims 18 and 19. That is, this is an embodiment of the invention for controlling the film drive and the heating body temperature in relation to the length of the recording material P used in the transport direction.

The general schematic structure of the image forming apparatus (1) (FIG. 1) and the structure of the fixing device (2) (FIGS. 2 and 3) in the first embodiment are the same in this embodiment. is there.

The control system is almost the same as that of the first embodiment, but the control unit of this embodiment controls the power supply by the signal output from the output port PT of the control circuit 101 to the fixing power supply 109 as shown in FIG. Then, the temperature of the heating element 14 can be switched between the first temperature and the second temperature lower than the first temperature.

Further, the drive signal F of the film motor 111
Two outputs of M are output, that is, a first speed that is a regular speed for fixing at the same speed as the developing device 6 and a third speed that is slower than the first speed.

FIG. 34 is a timing chart from the detection of the recording material P by the paper feed sensor 105 to the fixing of the recording material P. FIG. 34 (a) shows that when the length of the recording material P is longer than l.
(B) is a chart when it is shorter than l. FIG. 35 is a flowchart thereof.

FIG. 34 is a timing chart after the copy key 113 is turned on. Film motor 11
No. 1 is initially driven at the third speed, and the control temperature of the heating element 14 is the second temperature.

When the recording material P enters the paper feeding section, the paper feeding sensor 105 detects the presence of the recording material P (timing T
1) From this point, time t is counted.

Here, the time t is the time required for the recording material P having the length 1 to pass through the paper feeding section, and is stored in advance in the control circuit.

At the end of counting t (timing T2), the output of the paper feed sensor 105 is checked again. If the paper feed sensor 105 still detects the presence of the recording material P at this time, that is, the length of the recording material P is increased. When is longer than l,
When the pre-fixing sensor 112 detects the arrival of the recording material P (timing T3) as shown in (a), the drive speed of the film motor 111 is switched to the first speed, and the control temperature of the heating body 14 is switched to the first temperature. ..

Further, as shown in (b), if the paper feed sensor 105 does not detect the presence of the recording material P at the timing T2, that is, if the recording material P is shorter than l, even at the timing of T3. The film motor 111 is driven at the third speed, and the temperature of the heating body 14 is also maintained at the second temperature to perform the fixing.

In the flowchart of FIG. 35, it is detected at # 1 whether the recording material P has arrived at the paper feed section, and when the recording material P arrives, #
The time t is measured at 2.

When the time t has passed, the recording material P is fed to the paper feeding section at # 3.
If there is a recording material P, wait for the recording material P to arrive in front of the fixing device 11 in # 4, and then in # 5. The drive speed of 111 is switched to the first speed, and the control temperature of the heating element 14 is switched to the first temperature in # 6.

By thus detecting the length of the recording material P and switching the drive speed of the film 18 of the fixing device 11 according to the length, the time during which the recording material P does not exist in the fixing device 11 is shortened. Therefore, the electric power supplied to the fixing device can be effectively used.

Further, when fixing the same number of sheets, the number of sliding times of the film 18 is smaller than that of driving the film 18 at a constant speed, so that damage to the film can be reduced.

When the recording material P is small, the fixing temperature is low, so that the heat damage given to the film 18 can be reduced.

Further, when a recording material having a small size and a large thickness such as a postcard or a business card is used, the driving speed of the film is low, so that the temperature stability at the time of fixing is increased and the fixing failure does not occur. ..

<Fifteenth Embodiment> (FIGS. 36 to 38) This embodiment is another control example of the fifteenth embodiment.

FIG. 36 is a block diagram of the control unit of this embodiment. The control unit of this example is the same as that of the fourteenth embodiment (see FIG.
3) is further provided with a length sensor 123 for detecting the length of the recording material P, and is otherwise the same.

The length sensor 123 is the paper feed sensor 105.
It is installed at a distance of 1 from. The distance l here is the same as the length l in the fourteenth embodiment.

FIG. 37 is a timing chart from the detection of the recording material P by the paper feed sensor 105 to the fixing of the recording material P. FIG. 37 (a) shows that when the length of the recording material P is longer than l.
(B) is a chart when it is shorter than l. FIG. 38 is a flowchart thereof.

In the timing chart of FIG. 37, after the recording material P arrives at the paper feeding portion (timing T1), the length sensor 123 detects the recording material P at timing T2. At this time, if the paper feed sensor 105 still detects the presence of the recording material P as shown in (a), it waits for the recording material P to arrive at the pre-fixing sensor 112, and then the drive speed of the film motor 111 is set to the first value. The speed is switched to 1 and the control temperature of the heating element 14 is switched to the first temperature.

When the length sensor 123 detects the recording material P and the recording material P is not present in the paper feed sensor 105 as shown in (b), the speed of the film motor 111 is the third.
Fixing is performed at the same speed and the control temperature of the heating element 14 at the third temperature.

In the flow chart of FIG. 38, when it is detected that the recording material P has arrived at the paper feed section in # 1, it waits for the recording material P to arrive at the length sensor 123 in # 2, and when it arrives, it is fed in # 3. It is checked whether or not the recording material P is still present in the copy, and if not, the fixing is performed at the third speed.

When the presence of the recording material P is detected in # 3, the process waits for the recording material P to arrive at the pre-fixing sensor 123 in # 4.
In # 5, the drive speed of the film motor 111 is switched to the first speed, and in # 6, the control temperature of the heating body 14 is switched to the first temperature.

Other device configurations and controls are the same as in the first embodiment. This embodiment also has the same operation and effect as the above-mentioned fourteenth embodiment.

[0254]

As described above, according to the present invention, in the image forming apparatus in which the image fixing means is the film type fixing device, the items (A) to ((A) to () described above are mentioned. It is possible to solve problems such as F), and the intended purpose is often achieved.

[Brief description of drawings]

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

FIG. 2 is a schematic configuration diagram of an example of a film type fixing device using an endless belt-shaped fixing film.

FIG. 3 is a schematic configuration diagram of an example of a film type fixing device using a roll-wound end fixing film.

FIG. 4 is a block diagram of a control unit.

FIG. 5 is a plan view of the operation unit

FIG. 6 is an operation timing chart from when the copy key is pressed until the film reaches the first speed.

[Fig. 7] Operation flowchart

FIG. 8 is a timing chart of a film driving operation between sheets.

FIG. 9 is a flowchart of the operation

FIG. 10 is an operation flowchart when the copy operation ends.

FIG. 11 is an operation timing chart at the end of a copy operation in the image forming apparatus of the second embodiment.

FIG. 12 is a flowchart of the operation

FIG. 13 is a block diagram of a control unit of the image forming apparatus according to the fourth embodiment.

FIG. 14 is a timing chart of a film driving operation between sheets.

FIG. 15 is a flowchart of the operation

FIG. 16 is a block diagram of a control unit of an image forming apparatus according to a sixth embodiment.

FIG. 17: The film is first displayed after the copy key is pressed.
Operation timing chart up to speed

FIG. 18 is a flowchart of the operation

FIG. 19 is an operation flowchart of the image forming apparatus according to the seventh embodiment from when the copy key is pressed until the film reaches the first speed.

FIG. 20 is a block diagram of a control unit of the image forming apparatus according to the eighth embodiment.

FIG. 21: The film is first displayed after the copy key is pressed.
Operation timing chart up to speed

FIG. 22 is a block diagram of a control unit of the image forming apparatus of the ninth embodiment.

FIG. 23: The film is first displayed after the copy key is pressed.
Operation timing chart up to speed

FIG. 24 is a block diagram of a control unit of the image forming apparatus according to the tenth embodiment.

FIG. 25: The film is first displayed after the copy key is pressed.
Operation timing chart up to speed

FIG. 26 is a block diagram of a control unit of the image forming apparatus according to the eleventh embodiment.

FIG. 27: The film is first displayed after the copy key is pressed.
Operation timing chart up to speed

28A and 28B are timing charts of the fixing speed switching operation of the image forming apparatus according to the twelfth embodiment, in which FIG. 28A is for a recording material longer than a predetermined length, and FIG. Things

FIG. 29 is a flowchart of the switching operation.

FIG. 30 is a block diagram of a control unit of the image forming apparatus according to the thirteenth embodiment.

FIG. 31 is a timing chart of a fixing speed switching operation, in which (a) is a recording material whose length is longer than a predetermined length and (b) is a short recording material.

FIG. 32 is a flowchart of the operation

FIG. 33 is a block diagram of a control unit of the image forming apparatus according to the fourteenth embodiment.

34A and 34B are timing charts of a switching operation (fixing switching) between a fixing speed and a fixing temperature, where (a) is a recording material whose length is longer than a predetermined length and (b) is a short recording material.

FIG. 35 is a flowchart of the switching operation.

FIG. 36 is a block diagram of a control unit of the image forming apparatus according to the fifteenth embodiment.

FIG. 37 is a timing chart of a switching operation (fixing switching) between the fixing speed and the fixing temperature, where (a) is for a recording material longer than a predetermined length and (b) is for a shorter recording material.

FIG. 38 is a flowchart of the switching operation.

[Explanation of symbols]

 11 General Reference Code of Fixing Device 14 Heater 15 Heater Substrate 16 Electric Heater 17 Temperature Detector (Thermistor) 18 Fixing Film 21 Pressure Roller P Recording Material (Transfer Material) 101 Control Circuit (Microcomputer) 102 ROM 103 RAM 104 Original Stand sensor 105 Paper feed sensor 106 Paper discharge sensor 107 Main motor 109 Fixing power supply 110 Operation unit 111 Film motor 112 Pre-fixing sensor 113 Copy key 121 FMON sensor 122 Timer 123 Length sensor

Claims (19)

[Claims] 1. An image fixing device has a heating body that generates heat when energized, and a film that is slidably driven on the heating body, and a surface of the film opposite to the heating body side is provided with an image forming unit. In the image forming apparatus, which is a film-type fixing device, in which the toner image-bearing recording material of (3) is brought into close contact with the film and moved through the position of the heating body together with the film to heat and fix the toner image by the heat from the heating body through the film, An image forming apparatus, characterized in that after the power supply to the heating body of the apparatus is stopped, the speed of the film being driven at the first speed is switched to the second speed, and thereafter the driving of the film is stopped. 2. After the power supply to the heating element of the fixing device is stopped,
The image forming apparatus according to claim 1, further comprising: a unit that determines a timing at which the film driving is stopped, and the film driving is stopped when the timing is detected. 3. The first speed is a normal drive speed of a film when fixing a toner image, and the second speed is faster than the first speed.
The image forming apparatus described. 4. An image fixing device has a heating body that generates heat when energized and a film that is slidably driven on the heating body, and a film is formed on the surface of the film opposite to the heating body side from the image forming unit. In the image forming apparatus, which is a film-type fixing device, in which the toner image-bearing recording material of (3) is brought into close contact with the film and moved through the position of the heating body together with the film to heat and fix the toner image by the heat from the heating body through the film, When the recording material is present in the apparatus, the film is driven at the first speed, and when the recording material leaves the fixing device, the film drive is switched to the second speed, and when the recording material is introduced into the fixing device again. An image forming apparatus characterized in that the film drive is switched to a first speed. 5. A means for determining a timing T1 at which the film drive is switched from the first speed to the third speed, and a means for determining a timing T2 at which the film speed is switched from the third speed to the first speed, and the timing T1 is provided. 5. The image forming apparatus according to claim 4, wherein the film drive is switched from the first speed to the third speed when it is detected, and the film drive is switched from the third speed to the first speed when timing T2 is detected. 6. The method according to claim 4, wherein the first speed is a normal drive speed of the film when fixing the toner image, and the third speed is slower than the first speed. The image forming apparatus described in 5 above. 7. An image fixing device has a heating body that generates heat when energized, and a film that is slidably driven on the heating body, and a surface of the film opposite to the heating body side is provided with an image forming unit. In the image forming apparatus, which is a film-type fixing device, in which the toner image-bearing recording material of (3) is brought into close contact with the film and moved through the position of the heating body together with the film to heat and fix the toner image by heat from the heating body through the film, Image formation characterized in that the film is driven at a third speed from the start of the fixing device until the recording material is introduced into the fixing device, and is driven at the first speed when the recording material is introduced into the fixing device. apparatus. 8. A means for deciding a timing T1 for starting the driving of the film at the third speed after the start of the image forming operation of the image forming section, and a means for deciding the timing T2 for switching the film driving to the first speed. 8. The image according to claim 7, wherein when the timing T1 is detected, energization of the heating element and driving of the film at the third speed are started, and when the timing T2 is detected, the driving of the film is switched to the first speed. Forming equipment. 9. The method according to claim 7, wherein the first speed is a normal drive speed of the film when fixing the toner image, and the third speed is slower than the first speed. The image forming apparatus described in 8 above. 10. An image fixing device has a heating body that generates heat when energized, and a film that is slidably driven on the heating body, and a surface of the film opposite to the heating body side is provided with an image forming unit. In the image forming apparatus, which is a film-type fixing device, in which the toner image-bearing recording material of (3) is brought into close contact with the film and moved through the position of the heating body together with the film to heat and fix the toner image by heat from the heating body The apparatus has means for detecting the temperature of the heating body of the apparatus, and when the temperature detected by the temperature detecting means at the start of the image forming operation of the image forming section is below a predetermined temperature, the film is driven at the third speed, An image forming apparatus characterized in that when the recording material is introduced from the image forming section to the fixing device, the film drive is switched to the first speed. 11. When the film is being driven at a third speed, it has a means for detecting the timing of switching the driving of the film to the first speed, and when this timing is detected, the driving of the film is switched to the first speed. The image forming apparatus according to claim 10, wherein: 12. The method according to claim 10, wherein the first speed is a normal drive speed of the film when fixing the toner image, and the third speed is slower than the first speed. The image forming apparatus described in 11 above. 13. An image fixing device has a heating body that generates heat when energized, and a film that is slidably driven on the heating body, and a surface of the film opposite to the heating body side is provided with an image forming unit. In the image forming apparatus, which is a film-type fixing device, in which the toner image-bearing recording material of (3) is brought into close contact with the film and moved through the position of the heating member together with the film to heat and fix the toner image by heat from the heating member It has a means to measure the time from the end of the operation,
When the next image forming operation is started after measuring a predetermined time or more, the film of the fixing device is driven at the third speed, and when the toner image is fixed, the film is driven at the first speed. An image forming apparatus characterized by switching to. 14. When the film is driven at a third speed, the device has means for detecting a timing for switching the film driving speed to the first speed, and when the timing is detected, the film driving speed is set to the first speed. The image forming apparatus according to claim 13, wherein the image forming apparatus is switched. 15. The method according to claim 13, wherein the first speed is a normal drive speed of the film when fixing the toner image, and the third speed is slower than the first speed. 14. The image forming apparatus described in 14 above. 16. An image fixing device has a heating body that generates heat when energized, and a film that is slidably driven on the heating body. The image forming unit is provided on a surface of the film opposite to the heating body side. In the image forming apparatus, which is a film-type fixing device, in which the toner image-bearing recording material of (3) is brought into close contact with the film and moved through the position of the heating body together with the film to heat and fix the toner image with the heat from the heating body, An image forming apparatus characterized in that the driving speed can be switched in at least two stages and has means for detecting the length of the recording material used in the conveying direction, and the film driving speed can be varied depending on the length of the recording material. .. 17. The image forming apparatus according to claim 16, wherein the driving speed of the film is controlled to be slower when the length of the recording material is shorter than when the length of the recording material is long. 18. An image fixing device has a heating body that generates heat when energized, and a film that is slidably driven on the heating body, and a surface of the film opposite to the heating body side is provided with an image forming unit. In the image forming apparatus, which is a film-type fixing device, in which the toner image-bearing recording material of (3) is brought into close contact with the film and moved through the position of the heating body together with the film to heat and fix the toner image with the heat from the heating body, The drive speed and the control temperature of the heating element can be switched in at least two stages, and the device has a means for detecting the length of the recording material used in the transport direction. The control of the film driving speed and the heating element depending on the length of the recording material. An image forming apparatus characterized by switching the temperature. 19. The image forming apparatus according to claim 18, wherein the shorter the length of the recording material is, the slower the film drive speed is and the lower the control temperature of the heating member is, compared with the long length.