JPH07248700A - Heating device, image heating device and image forming device - Google Patents

Abstract

PURPOSE:To prevent generation of high-temperature offsetting and lack of heating of an image by determining the heating temperature of the first supplying sheet members to be heated and reducing heating temperature in accordance with the number of supplying sheet members when the sheet members to be heated are continuously supplied. CONSTITUTION:The heating condition of a device is detected when power supply to a heating member (heater) 6 is cut off and heating is started to be applied to a next member to be heated (a material to be recorded) P, a temperature determining means (CPU) 10 is provided for determining the set temperature of the heating member 6 necessary for the first supplying sheet member to be heated in accodance with a detected level and the heating temperature of the heading member 6 is gradually reduced when the members to be heated P are continuously supplied. The heating condition of the device is detected immediately prior to starting of supplying the first member to be heated P, and in accordance with the detected level thereof, the set temperature of the heating member 6 is changed corresponding to the number of supplied members to be heated P.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device, an image heating device, and an image forming apparatus.

More specifically, a heating member, a temperature detecting member for detecting the temperature of the heating member, and a temperature detecting member for heating the member to be heated so that the temperature detected by the temperature detecting member is kept constant at a predetermined heating temperature. The present invention relates to a heating device that has an energization control unit that controls energization to a heating member, and heats a heated member that has passed through the device with heat from the heating member.

In an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus, an appropriate image forming process means is used on a recording material (image supporting member) such as a transfer material, a photosensitive paper or an electrostatic recording paper. The present invention relates to an image heating device that heats an image that has been formed and carried to perform image fixing, surface modification such as gloss, and hypothetical attachment, and an image forming device including the image heating device.

[0004]

2. Description of the Related Art As a heat fixing device which is a typical image heating device, there are disclosed in JP-A-63-313182 and JP-A-2-1.
Japanese Patent Laid-Open No. 57878 proposes a film heating type device using a heating body (hereinafter referred to as a heater) having a high temperature rise as a heating member and a thin film.

FIG. 4 shows a schematic diagram of the structure of an example of the film heating type image heating apparatus. That is, a thin heat-resistant film 2 (or sheet), a movement driving means 51 for the film 2, and a heater 6 which is fixedly supported on one side of the film 2 with the film 2 in between and which is controlled at a constant temperature. And pressurizing the developed image-bearing surface of the recording material P as a heated material to be image-fixed to the heater 6 on the other surface side so as to face the heater 6 through the film 2. The film 2 has a member (pressurizing roll) 4, and at least when the image fixing is performed, the film 2 is conveyed in the space between the film 2 and the pressing member 4 and is substantially forward in the forward direction with respect to the recording material P to be image-fixed. The recording material P is visualized by passing through the nip portion N as a fixing portion formed by press contact between the heater 6 and the pressing member 4 with the traveling moving film 2 sandwiched therebetween while traveling at the same speed. The supporting surface is heated by the heater 6 through the film 2. Image (unfixed toner image) the thermal energy imparted allowed softened and melted to T, then a heating apparatus which is based on that the film 2 after fixing portion passing to separate the recording material P at the separation point.

In the apparatus of this example, an endless belt-shaped film 2 is used, which is suspended and stretched between three members of a driving roll 51, a tension roll 52, and a heater 6 and is rotationally driven by a driving roll 110. I am letting you.

The temperature of the heater 6 is controlled by controlling energization of the heater 6 to the heating element 6b so that the temperature detected by the thermistor 5 is constant.

Such a film heating type heating device can use the heating member 6 having a very small heat capacity and a rapid temperature rise, and the time required for the heating member 6 to reach a predetermined heating temperature can be greatly shortened.

[0009]

FIG. 5 is a schematic diagram showing changes over time in the heater temperature, film temperature, and pressure roll surface temperature at the time of fixing in such a film heating type image heating apparatus (heat fixing apparatus). It is a figure.

The heater 6 as a heating member is adjusted to a constant temperature of 200 ° C. at the start of fixing. Meanwhile, the pressure roll 4
Has a large heat capacity, the surface temperature gradually rises. At this time, the film temperature also gradually rises while taking an intermediate value between the heater temperature and the surface temperature of the pressure roll, and the change amount thereof reaches about 40 deg.

By the way, when the film temperature becomes β ° C. or lower, fixing failure occurs, and when it becomes α ° C. or higher, high temperature offset (hot offset) occurs.

Therefore, in order to prevent fixing failure, the heater temperature is set so that the film temperature becomes β ° C. or more for the first sheet of recording material to be passed, and the apparatus warms up and the recording material to be passed 7
High temperature offset occurs after the first sheet, and conversely, to prevent high temperature offset after the seventh sheet of recording material is passed, if the heater temperature is lowered, fixing is performed on the first sheet of recording material that is cold in the device. It causes a defect.

Therefore, it is conceivable to lower the heater temperature when a predetermined number of sheets are printed during continuous printing. However, depending on how the apparatus warms up, the first sheet of recording material for keeping the film temperature at an appropriate temperature may be used. Since the heater temperature and the number of sheets of recording material that are appropriate for lowering the heater temperature are different, high temperature offset and low temperature offset also occur.

Therefore, in the present invention, such a heating device is designed so that neither under-heating nor over-heating occurs, and in the image heating device of the image forming apparatus, the high temperature of the image is obtained regardless of the process speed. The purpose is to prevent offset and insufficient heating.

[0015]

The present invention is a heating device, an image heating device, and an image forming device characterized by the following constitutions.

(1) A heating member, a temperature detecting member for detecting the temperature of the heating member, and the heating member for heating the member to be heated so that the temperature detected by the temperature detecting member is kept constant at a predetermined heating temperature. In a heating device having an energization control means for controlling energization to a member, and heating the member to be heated passed through the device with heat from the heating member, the heating device is heated based on the temperature of the heating member before the start of temperature control. It has a temperature deciding means for deciding the heating temperature of the first sheet of the heating member, and a temperature deciding means for lowering the heating temperature according to the number of sheets to be passed when continuously feeding the heated member. Characteristic heating device.

(2) A heating member, a temperature detecting member for detecting the temperature of the heating member, and the heating so that the temperature detected by the temperature detecting member is maintained constant at a predetermined heating temperature when the member to be heated is heated. In a heating device that has an energization control unit that controls energization to a member, and heats a heated member that has been passed through the device with heat from the heating member, it is determined based on the temperature of the heating member before the start of temperature adjustment. And a temperature determining means for determining the heating temperature of the first sheet to be heated, by comparing the heated temperature with the temperature of the heating member at the time of the final sheet passage of the heated member before the power is turned off. A heating device comprising temperature determining means for lowering a heating temperature according to the number of sheets to be passed when continuously passing a heated member.

(3) In the heating device of (2), the heating temperature of the first sheet to be heated, which is determined by comparison, is selected to be higher.

(4) It has a film which moves in contact with the heating member, and a pressing member which forms a nip portion with the heating member through the film, and the member to be heated is introduced into the nip portion. The heating device according to any one of (1) to (3), wherein the heating device receives heat from the heating member via the film by moving and passing through the nip portion together with the film, and the heating process is performed.

(5) The energization control means turns off the energization to the heating member when the apparatus is on standby (1)
The heating device according to any one of (4) to (4). In the heating device, the image heating temperature of the first sheet of recording material to be compared and determined is selected to be higher.

(6) A heating member, a temperature detecting member for detecting the temperature of the heating member, and the heating member so that the detected temperature of the temperature detecting member is kept constant at a predetermined image heating temperature during image heating. An image heating apparatus having an energization control unit for controlling energization to a recording material, which heats an image on a recording material passed through the apparatus with heat from a heating member. Has a temperature determining means for determining the image heating temperature of the first sheet to be passed through the recording material, and when continuously passing the recording material, the image heating temperature is lowered according to the number of passed sheets. An image heating apparatus having a temperature determining means.

(7) A heating member, a temperature detecting member for detecting the temperature of the heating member, and the heating member so that the detected temperature of the temperature detecting member is kept constant at a predetermined image heating temperature during image heating. An image heating apparatus having an energization control unit for controlling energization to a recording material, which heats an image on a recording material passed through the apparatus with heat from a heating member. Image heating temperature determined based on the temperature of
The temperature determination means determines the image heating temperature of the first sheet of the recording material by comparing the temperatures of the heating members during the final passage of the recording material before the power is turned off. An image heating apparatus having a temperature determining unit that lowers the image heating temperature according to the number of sheets to be continuously fed.

(8) In the image heating apparatus of (7) above,
An image heating apparatus characterized by selecting a higher image heating temperature for the first sheet of recording material to be compared and decided.

(9) It has a film that moves in contact with the heating member, and has a pressing member that forms a nip portion with the heating member through this film, and the recording material is introduced into the nip portion. The image heating apparatus according to any one of (6) to (8), wherein the image is heated by receiving heat from a heating member through the film by moving and passing through the nip portion together with the film. .

(10) The image heating apparatus according to any one of (6) to (9), wherein the energization control means turns off the energization to the heating member when the apparatus is on standby.

(11) An image forming means for forming an image on a recording material, and an image on the recording material sent from the image forming means is subjected to a heat treatment (6) to (10). An image forming apparatus comprising the image heating device of FIG.

[0027]

When the heating member is de-energized and the heating process for the next member to be heated is started, the warming condition of the device is detected, and it is necessary to feed the first member to be heated according to the detection level. In addition to having a temperature determining means for determining the set temperature of the heating member, the heating temperature of the heating member is sequentially lowered when the heating target member is continuously fed, that is, it can be rapidly heated to a high temperature. In the heating device, the warming condition of the device is detected immediately before the first sheet to be heated is started to pass, and the set temperature of the heating member is changed corresponding to the number of passed sheets of the heated member according to the detection. As a result, it is possible to provide a heating device that does not generate insufficient heating or excessive heating.

When this apparatus is used as an image heating apparatus for a recording material of an image forming apparatus, high temperature offset of an image and insufficient heating do not occur regardless of process speed.

[0029]

【Example】

Example 1 (1) Example of Image Forming Apparatus FIG. 1 shows a schematic configuration of an example of the image forming apparatus. The image forming apparatus of this embodiment is a reciprocating platen type, a rotary drum type, a transfer type, and a process cartridge attaching / detaching type electrophotographic copying apparatus.

Reference numeral 100 is an apparatus casing, 101 is a reciprocating type document placing table made of a transparent plate member such as a glass plate disposed on an upper surface plate 102 of the apparatus casing, and the apparatus casing upper surface plate 101
The upper part 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, which is placed on the upper surface of the original placing table 101 with the image surface side to be copied facing downward according to a predetermined placing standard, and the original pressure plate 103 is placed on the original placing table 103 and pressed down. Set.

Reference numeral 104 denotes a slit opening serving as a document illuminating section, which is opened on the surface of the machine top plate 102 with the direction perpendicular to the reciprocating direction of the document placing table 101 (direction perpendicular to the paper surface) as the longitudinal direction.

The downward image surface of the document G placed and set on the document placing table 101 sequentially moves the positions of the slit openings 104 from the right side to the left side in the forward movement process of the document placing table 101 to the right a. The light L of the lamp 105 is passed through the slit opening 104 and the transparent original placing table 101 to be illuminated and scanned in the passing process, and the original surface reflected light of the illumination scanning light is reflected by the image element array 106 by the photosensitive drum. Image formation exposure is performed on the 107th surface.

The photosensitive drum 107 is coated with a photosensitive layer such as a zinc oxide photosensitive layer or an organic semiconductor photosensitive layer, and is rotated in a clockwise direction indicated by an arrow b at a predetermined peripheral speed about a central support shaft 108. During the rotation process, the charging device 109 receives a uniform positive or negative charging process, and the uniformly charged surface is subjected to the image formation exposure (slit exposure) of the original image, so that the surface of the photosensitive drum 107 is formed. An electrostatic latent image corresponding to the image-exposed original image is sequentially formed.

This electrostatic latent image is sequentially visualized by a developing device 110 with toner made of resin or the like that is softened and melted by heating, and the toner image as the visualized image is provided with a transfer discharger 111 as a transfer portion. It moves to the part.

Reference numeral S denotes a cassette in which transfer material sheets P as recording materials are stacked and housed, and the sheets in the cassette are fed out and fed one by one by the rotation of the feeding roll 112.
Next, when the leading edge of the toner image forming portion on the drum 107 reaches the portion of the transfer discharger 111 by the resist roll 113, the leading edge of the transfer material sheet P also reaches exactly the position between the transfer discharger 111 and the photosensitive drum 107. Then, the sheets are synchronously fed with the timing adjusted so that they coincide with each other.

Then, the toner images on the side of the photosensitive drum 107 are sequentially transferred by the transfer discharger 111 onto the surface of the fed sheet.

The sheet to which the toner image has been transferred at the transfer portion is sequentially separated from the surface of the photosensitive drum 107 by a separating means (not shown), and is guided to the image heating device (heat fixing device) 50 by the conveying device 114 to be carried. The unfixed toner image that has been subjected to heat fixing is discharged as an image-formed product (copy) onto a discharge tray 117 outside the machine through a discharge roll 116.

The surface of the photosensitive drum 107 after the image transfer is subjected to removal of adhered contaminants such as transfer residual toner by the cleaning device 118, and is repeatedly used for image formation.

The PC is a process cartridge that is attached / detached to / from the cartridge attaching / detaching portion 120 in the apparatus main body 100.
In the case of the present example, the apparatus main body 10 including the four process devices of the photosensitive drum 107 as an image bearing member, the charging device 109, the developing device 110, and the cleaning device 118 together.
It is detachable and replaceable with respect to 0.

(2) Image Heating Device 50 FIG. 2 is a schematic view of the image heating device 50. The image heating apparatus 50 of this example is disclosed in Japanese Patent Laid-Open No. 4-44075-44083.
This is an image heating apparatus of tensionless type film heating system disclosed in Japanese Patent Publication No. 4-204980-204984 and the like.

In this type of device, at least part of the circumference of the film is always tension-free (a state in which no tension is applied), and the traveling movement of the film is obtained from the rotational driving force of the pressing member. Even if the same film heating type device is used, as in the device shown in FIG.
The advantage is that the control and mechanism such as driving and running of the film is simplified, and the driving torque can be greatly reduced, compared to the tension type in which the tension is constantly applied all over the circumference to move in tension. .

Reference numeral 1 denotes a horizontally long stay made of heat-resistant resin, which serves as an inner surface guide member of the endless heat-resistant film 2 described below.

The endless heat-resistant film 2 is fitted onto the stay 1 including a heater (heating body) 6 as a heating member. The inner peripheral length of the endless heat-resistant film 2 and the outer peripheral length of the stay 1 including the heater 6 are larger than those of the film 2 by, for example, 3 mm.
Is loosely fitted to the stay 1 including the heater 6 with a sufficient circumferential length.

The film 2 has a total thickness of 10 in order to reduce the heat capacity and improve the quick start property.
PTFE / PF with heat resistance, releasability, strength and durability of 0 μm or less, preferably 50 μm or less, 20 μm or more
PT on a single layer such as A / FEP or on the outer surface of polyimide / polyamideimide / PEEK / PES / PPS
A composite layer film coated with FE / PFA / FEP can be used. In this example, a polyimide film coated with PTFE on the outer peripheral surface was used.

The heater 6 is a substrate 6a made of alumina or the like.
Along the length of the center of the surface of, for example, Ag / Pd
An electric resistance material (heating element) 6b such as (silver-palladium) is applied to the thickness of about 10 μm and a width of 1 to 3 mm by screen printing or the like, and glass, a fluororesin or the like is coated thereon as a protective layer 7.

Reference numeral 4 denotes a film pressure roll as a rotating body for driving the film 2 by forming the fixing nip portion N by sandwiching the film 2 between the heater 6 and the core shaft 4a and the exterior of this shaft. And a roll portion 4b made of a heat-resistant rubber elastic body having good releasability such as a silicon rubber, and the end portion of the core shaft 4a is driven in the counterclockwise direction indicated by an arrow by being driven by a driving means (not shown). Driven. When the pressure roll 4 is rotationally driven, the endless heat resistant film 2 is also rotationally driven in the clockwise direction shown by the arrow.

When the endless heat-resistant film 2 is not driven, most of the remaining portion except the portion sandwiched by the nip portion N between the heater 6 and the pressure roll 4 is tension-free. .

When the pressure roll 4 is rotationally driven, a moving force is applied to the film 2 at the nip portion N by a frictional force between the film 2 and the rotary pressure roll 4, and the film 2 has a speed substantially equal to the rotational peripheral speed of the pressure roll 4. The back surface of the film is driven to rotate clockwise while sliding on the heater 6 surface (= protective layer 7 surface). When the film is driven, the nip portion N and the nip portion N are
Tension is applied to the film only on the upstream side in the film moving direction and between the nip portion and the film inner surface guide portion near the nip portion.

In the state in which the film is driven and the heater 6 is energized to the heating element layer 6b, the recording material P carrying the unfixed toner T is placed on the rotating film 2 in the nip portion N.
When the recording material P is introduced between the rotary pressing roller 4 and the rotary pressing roll 4 upward, the recording material P passes through the nip portion N together with the film 2 and is in contact with the back surface of the film at the nip portion N. The thermal energy of the heater 6 is applied to the recording material P via the film 2, and the toner image T is thermally fixed by the pressing force in the nip portion N.

(3) Temperature Control of Heater 6 In the heater 6, voltage is applied (power supply) across the lengthwise ends of the heat generating layer 6b, so that the heat generating layer 6b generates heat and the substrate 6a is heated to a low temperature. The temperature of the entire heater 6, which is the heat capacity, rises rapidly and rises rapidly.

In order to control the temperature of the heater 6, the output of the thermistor 5 provided on the heater 6 is A / D converted and taken into the CPU 10. Based on the information, an AC is supplied to the heating element layer 6b of the heater 6 by the triac 11. The voltage is controlled by controlling the power supplied to the heater by controlling the phase and wave number. 12
Is an AC power supply.

That is, when the temperature detected by the thermistor 5 is lower than a predetermined set temperature, the heater 6 is heated, and when it is high, the heater 6 is cooled so that the heater 6 is cooled. The temperature is adjusted to a certain level.

Reference numeral 13 is a main control circuit of the image forming apparatus,
The fixing operation is continuously executed during continuous printing by a plurality of image forming commands (print commands). In addition, the power supply to the heater 6 is turned off during the standby for waiting the print command, and the power supply to the heater 6 is started after the print command is issued by turning on the main switch.

A. Determination of Fixing Temperature at Heater Startup When there is a print command, the fixing temperature is first determined at heater startup as follows.

.. When the print command is input, the thermistor 5 detects the temperature T ₀ of the heater 6 when the apparatus is in standby (heater temperature immediately before the start of operation).

.. From the detected temperature T ₀ , the heater temperature T ₁ for adjusting the temperature of the first print is determined by the table shown in Table 1.

The CPU 10 has a temperature determining function for determining the heater controlled temperature T ₁ of the first print according to the table shown in Table 1 based on the temperature T ₀ of the heater 6 before the start of temperature control detected by the thermistor 5. Have.

[0059]

[Table 1] ． After printing the first sheet of the heater temperature adjustment temperature T ₁ is determined, the heater 6 rises energized.

.. When the temperature detected by the thermistor 5 is detected 5 deg before the desired heater control temperature T ₁ , 300
Switch to constant power supply near W.

The constant power control is performed by controlling the phase and the wave number according to the AC power supply voltage value and the resistance value of the heater 6.

In the present embodiment, constant voltage energization is performed by detecting the input voltage and heater resistance before turning on the heater 6 and performing phase control.

In this embodiment, as shown in Table 1, the heater control temperature T ₁ is determined according to the detection level −5 of the temperature T ₀ . This is because when the detected temperature T ₀ is lower than 50 ° C., it is determined that the device is cold, and the higher temperature control temperature 190
Select ° C. Then, it is determined that the apparatus is warming as the detected temperature T ₀ increases, and the heater temperature control temperature T ₁
I try to select a lower value.

B. Determination of Fixing Temperature During Continuous Printing It is necessary to switch the fixing temperature depending on how warm the device 50 is during continuous printing.

As the apparatus 50 warms up, heat is supplied from the pressure roller 6 to the recording material (paper) P, so that the total amount of heat applied to the recording material P is always kept constant. This is because the control temperature of the heater 6 has to be gradually lowered.

If the temperature on the heater 6 side is not lowered, the heat is excessively supplied to the recording material and the toner is excessively melted to cause high temperature offset.

As a method of temperature control switching during this continuous printing, in the present embodiment, as shown in Table 2, the switching time is determined by the heater temperature control temperature T ₁ described above and the number of sheets passed. .

The CPU 10 has a temperature determining function for switching the heating set temperature T ₁ in the lowering direction as shown in Table 2 according to the number of sheets passed during continuous printing.

[0069]

[Table 2] By controlling in this way, the set temperature T ₁ of the heater 6 is always switched at an appropriate timing regardless of whether the apparatus 50 is sufficiently cooled or sufficiently warmed, and the recording material P is directly The temperature of the film heated by contact is kept substantially constant in the range of α ° C and β ° C as shown in FIG.

In this way, the warming condition of the device 50 immediately before printing is detected, the heater temperature control temperature T ₁ of the first print sheet is determined according to the detected temperature, and the heater temperature control temperature is determined according to the number of sheets passed thereafter. By determining T ₁ , it became possible to prevent both fixing failure and high temperature offset. In addition, this method has an advantage that the temperature adjustment temperature T ₁ is set without depending on the process speed, and it is easy to cope with the speedup.

<Embodiment 2> In Embodiment 1, the temperature control temperature T ₁ is set differently according to the detected temperature T ₀ , but it is more preferable to divide the temperature control temperature T ₁ more finely. This is an example of this embodiment.

Specifically, as shown in Table 3, the detected temperature T ₀ is divided into 8 levels, and the temperature adjusted temperature T ₁ is determined correspondingly. Then, as shown in Table 4, the temperature control temperature is lowered according to the number of prints with respect to the temperature control temperature T ₁ .

By doing so, even when the heater temperature of the first print is regulated to the same 180 ° C., the temperature before printing is 50 to 60 ° C. and 60 to 70 ° C.
The number of sheets to switch from 180 ° C to 170 ° C is different from the fifth sheet to the third sheet. Therefore, the temperature of the film 2 enters a smaller width and the variation toward the high temperature side is reduced, so that the high temperature offset margin can be increased.

[0074]

[Table 3] <Third Embodiment> In the first and second embodiments, the heater temperature of the first print is determined by the heater temperature T ₀ immediately before printing. In this embodiment, however, the control at that time is performed at the end of printing. The temperature T ₂ and the number of recording materials (the number of printing materials) N are stored.

Then, the temperature-controlled temperature T ₁ determined by the heater temperature T ₀ is compared with the previous data T _2, and the larger one is given priority to be the control value.

In this embodiment, the CPU 10 controls the temperature T ₁ determined based on the detected temperature T ₀ of the heater 6 before the start of the temperature control, and the heater 6 at the time of the final passage of the recording material before the energization is turned off. A temperature determining function for determining the heater control temperature T ₁ of the first print by comparing the control temperature T ₂ of the prints and decreasing the control temperature T ₁ according to the number of passed sheets during continuous printing. It has a decision function.

For example, suppose that the previous print was in the state of (3) in Table 4 and the print was completed at the fifth sheet under control at 170 ° C. In this situation, when the device 50 is getting cold, immediately after the end, from Table 4 (4) to (8), T ₁
= Select 170 ° C~150 ° C, which is below its order stored have been T ₂ = 170 ° C.

Therefore, in this case, if the control temperature T ₂ is prioritized and the print signal is input again, 170 ° of (3) in Table 4 is obtained.
After returning to the control from C and the sixth sheet, the subsequent control is performed.

On the other hand, when the apparatus 50 cools to the states (1) to (3) in Table 3, T ₁ = 180 ° C. to ₁
Since the temperature becomes 90 ° C. and T ₁ > T ₂ , the memory is reset and the control is newly started by T ₁ from the first sheet.

In this way, by comparing the detected temperature T ₁ and the control temperature T ₂ and giving priority to the higher one, not only simple continuous printing but also continuous printing and intermittent printing are mixed. Even if the heater 6 is at a high temperature, the entire device may not be warmed. By storing the control temperature T ₂ and the number of printed sheets N in such a situation, the warming condition of the apparatus 50 can be reflected in the control, and the control can be performed in a range without fixing failure and high temperature offset. . The switching during continuous printing follows Table 4 and is the same as described above.

Although each of the above embodiments is the tensionless type film heating type image heating apparatus, the tension type film heating type image heating apparatus of FIG. 4 and other types of heating apparatus or image heating apparatus are described. Also, the same effect can be obtained by applying the present invention.

[0082]

As described above, according to the present invention, the heating member, the temperature detecting member for detecting the temperature of the heating member, and the temperature detected by the temperature detecting member when heating the member to be heated are kept constant at a predetermined heating temperature. A heating device that has an energization control unit that controls energization of the heating member so that the heating member is maintained, and heats the heated member that has been passed through the device with heat from the heating member. It is possible to prevent any of the above from occurring, and in the image heating apparatus of the image forming apparatus, it is possible to prevent high temperature offset and insufficient heating of the image regardless of the process speed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an example of an image forming apparatus.

FIG. 2 is a schematic configuration diagram of an image heating apparatus (tensionless type film heating method) used.

FIG. 3 is a graph showing changes in film temperature and heater temperature with time.

FIG. 4 is a schematic view of an example (tension type) of a film heating type heating device as an image heating device.

FIG. 5: Time-dependent change diagram of each temperature of heater, film, and pressure roll

[Explanation of symbols]

 50 heating device (image heating device) 1 film guide member 2 heat resistant film 4 pressure roll 5 thermistor (temperature detection member) 6 heater (heating member) 6a heater substrate 6b heating element layer 7 protective layer 10 CPU (temperature determining means) 11 Triac (energization control means) 12 AC power source P Recording material (heated member) N Fixing nip part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Abe 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Manabu Takano 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Ryo Hayakawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (11)

[Claims] 1. A heating member, a temperature detecting member for detecting the temperature of the heating member, and the heating member so that the temperature detected by the temperature detecting member is kept constant at a predetermined heating temperature when the member to be heated is heated. In a heating device that has an energization control unit that controls the energization to the device, and heats the heated member that has been passed through the device with the heat from the heating member, the heating target is based on the temperature of the heating member before the start of temperature adjustment Material passing 1
A heating device having a temperature determining means for determining the heating temperature of the first sheet and further having a temperature determining means for lowering the heating temperature in accordance with the number of sheets to be passed when continuously passing the heated member. . 2. A heating member, a temperature detecting member for detecting the temperature of the heating member, and the heating member so that the temperature detected by the temperature detecting member is kept constant at a predetermined heating temperature when the member to be heated is heated. In a heating device that has an energization control unit that controls the energization to the device, and heats the heated member that has been passed through the device with the heat from the heating member, it was determined based on the temperature of the heating member before the start of temperature adjustment. It has a temperature determining means for comparing the heating temperature with the temperature of the heating member at the time of passing the final heated member before turning off the energization, and having a temperature determining means for determining the heating temperature of the first sheet to be heated. A heating device comprising temperature determining means for lowering the heating temperature according to the number of sheets to be passed when the heating member is continuously passed. 3. The heating device according to claim 2, wherein the heating temperature of the first sheet to be heated, which is determined by comparison, is selected to be higher. 4. A film having a film that moves in contact with a heating member, and a pressure member that forms a nip portion with the heating member through the film, and the member to be heated is introduced into the nip portion and the film is introduced. The heating device according to any one of claims 1 to 3, wherein heat is received from a heating member via the film by moving and passing through the nip portion together with the heating device. 5. The heating device according to any one of claims 1 to 4, wherein the energization control means turns off the energization to the heating member when the device is on standby. 6. A heating member, a temperature detecting member for detecting the temperature of the heating member, and a heating member for detecting the temperature of the heating member so that the temperature detected by the temperature detecting member is kept constant at a predetermined image heating temperature. In an image heating device having an energization control means for controlling the energization of the recording material, the image heating device heats the image on the recording material passed through the device with heat from the heating member. A temperature determining means for determining the image heating temperature of the first sheet of recording material based on the temperature;
An image heating apparatus having a temperature determining unit that lowers the image heating temperature according to the number of sheets to be passed when the recording material is continuously passed. 7. A heating member, a temperature detecting member for detecting the temperature of the heating member, and a heating member for maintaining the detection temperature of the temperature detecting member at a predetermined image heating temperature during image heating. In an image heating device having an energization control means for controlling the energization of the recording material, the image heating device heats the image on the recording material passed through the device with heat from the heating member. The image heating temperature determined based on the temperature is compared with the temperature of the heating member during the final passage of the recording material before the energization is turned off to determine the image heating temperature of the first sheet of the recording material. An image heating apparatus having means, and temperature determining means for lowering the image heating temperature according to the number of sheets to be passed when continuously passing a recording material. 8. The image heating apparatus according to claim 7, wherein the higher image heating temperature of the first sheet of recording material to be compared and determined is selected. 9. A film having a film that moves in contact with a heating member, and a pressure member that forms a nip portion with the heating member through the film, and the recording material is introduced into the nip portion and the film is introduced. 9. The image heating apparatus according to claim 6, wherein heat is applied to the image from the heating member via the film by moving and passing through the nip portion together with the image heating process. 10. The energization control means turns off energization to the heating member during standby of the apparatus.
The image heating device according to any one of 1 to 9 above. 11. The image according to claim 6, wherein the image forming means for forming an image on the recording material and the image on the recording material sent from the image forming means are heat-treated. An image forming apparatus comprising a heating device.