JPH09190112A - Fixing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress image glass irregularity without thinning a silicone rubber layer and without rapid temperature rising caused by a heater incorporated in a fixing roller. SOLUTION: When an auxiliary heater 16 is arranged on a transfer material rush-in side on the surface of the fixing roller 10, the transfer material 5 is held and carried between the roller 10 and a pressure roller 11, and heating is performed by the incorporated heater 15, the auxiliary heater 16 is heated with a timing that the roller 10 finishes rotating once so as to directly give the surface of the roller 10 a calorie taken away by the material 5. Thus, the change between fixing temperature of the roller 10 in the case of rotating once and the one in the case of rotating twice is restrained, so that the gloss irregularity can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device for melting and fixing a developer by heating, and an electrophotographic image forming apparatus equipped with this fixing device.

[0002]

2. Description of the Related Art A conventional full-color printer, which is one of electrophotographic image forming apparatuses, is constructed as shown in FIG. In FIG. 7, reference numeral 1 is a laser scanner unit, which forms an image of a laser beam emitted from the laser scanner unit 1 on the basis of an ON / OFF signal of a laser driver (not shown) on the photosensitive drum 2 and scans it, A latent image is formed on the photosensitive drum 2.

The latent image is developed by the developing cartridge housed in the developing rotary unit 3 which rotates counterclockwise as shown by the arrow. That is, each developing cartridge contains four color toners of magenta, cyan, yellow, and black, and each developing cartridge has a constant gap of about 300 μm with respect to the photosensitive drum 2 during development. By facing each other, each toner is attached to the latent image on the photosensitive drum 2, and for example, development is performed in the order of magenta, cyan, yellow, and black.

On the other hand, the transfer material 5 such as paper accommodated in the paper feed cassette 4 is supplied from the paper feed cassette 4 in the above process, and is temporarily stopped while being sandwiched by the registration rollers 6. Static electricity is applied to the transfer drum 7 by the attraction roller 8 that is in contact with the drum 7, and the transfer material 5 passes between the transfer drum 7 and the attraction roller 8 and then electrostatically attracts and winds around the transfer drum 7. At this point, the suction roller 8 separates from the transfer drum 7.

In this way, the toner image formed for each color of magenta, cyan, yellow, and black is transferred on each color on the transfer material 5 wound around the transfer drum 7,
A full-color image is formed by superimposing colors.

Next, the transfer material 5 on which the full-color image has been transferred is separated from the transfer drum 7 by the separating claw 9 which is in contact with the transfer drum 7, and a fixing roller 10 and a pressure roller 11 which are transfer material conveying means. And is conveyed to a fixing device having.

Then, the full-color toner image on the transfer material 5 is fixed on the transfer material 5 by being heated and pressed by the fixing roller 10 and the pressure roller 11, and after that, the full-color toner image is transferred through the paper discharge roller 12 to the machine. It is discharged to the outside.

The transfer drum 7 after the transfer process is completed.
The transfer cleaner unit 13 collects the toner remaining on the transfer drum 7, cleans the transfer drum, and removes the residual charge by the charge eliminating roller 14.

In all of the above steps, one full-color image was formed, and an image with excellent color reproducibility was formed on a transfer material such as paper.

[0010]

However, in the above-mentioned conventional example, in order to improve the releasability, the fixing roller 1 is generally used.
In No. 0, the surface of the metallic roller is coated with silicone rubber, but when the transfer material 5 passes through the fixing device, the fixing roller 1
Since the heat of 0 is taken to cause a temperature drop, the silicone rubber has a small thermal conductivity and takes a long time to rise in temperature, so that a fixing temperature difference may occur between the first and second rounds of the fixing roller 10. As a result, if the fixing temperature is high, the gloss becomes high, and conversely, if the fixing temperature is low, the gloss becomes low, so that uneven glossiness of the image occurs, and the appearance may deteriorate. For example, an average electric power of a halogen heater (not shown), which is a heating unit disposed in the fixing roller 10, is 220 W, a roller peripheral speed is 100 mm / sec, a nip portion has a width of about 5 to 6 m,
When a fixing temperature of 170 ° C. and a standard copy paper having a basis weight of 80 g / m ² are thrust into the fixing device 50, the surface temperature of the fixing roller 10 decreases by about 10 ° C. in the first and second laps. Is better obtained.

Therefore, it is conceivable to reduce the thickness of the silicone rubber layer. In this case, the fixing nip portion is formed as shown in FIG.
As shown in FIG. 8B, the state becomes as shown in FIG.
The effect of good fixing efficiency (wrapping effect) of fixing the toner on the transfer material by wrapping it in the fixing roller 10 cannot be obtained, and fixing failure may occur at the end of the upper layer of the multiple toner of the color image. In particular, when a transparent transfer material is fixed, it appears remarkably when projected on a screen by an overhead projector, and a pseudo contour in which a part of a color image becomes dark may occur.

Although it is considered that the temperature decrease is compensated for by the temperature increase of the heater, a rapid temperature increase on the surface of the fixing roller 10 cannot be expected because the heat capacity of the fixing roller 10 is large. Further, when a heater having improved performance is used and the temperature is rapidly raised, the interface temperature rises, resulting in material deformation, deterioration, cost increase, durability and safety deterioration of the fixing roller 10, and metal roller and silicone rubber There were peeling and further overshoot.

Therefore, according to the present invention, the fixing device and the image forming apparatus can suppress the uneven glossiness of the image without thinning the silicone rubber layer and without causing a rapid temperature rise by the heater contained in the fixing roller. The purpose is to provide a device.

[0014]

According to the first invention of the present application, the above object is to provide a transfer material transporting means for sandwiching and transporting a transfer material carrying an unfixed developer image, and the transfer material transporting means. And a heating means for heating the transfer material and the unfixed developer image through the sheet, and fixing the fixing material on the transfer material by melting the unfixed developer image by heating while nipping and transporting the transfer material. The heating means is provided at least at a position for heating the contact surface side of the transfer material conveying means with the transfer material at a position upstream of the sandwiching portion of the transfer material conveying means in the transfer material conveying direction. To be done.

According to the second invention of the present application,
In addition to the heating means of the first invention, the above-mentioned object is provided with a heating means for heating from a non-contact surface side of the transfer material conveying means with the transfer material, wherein the heating means of the first invention is a transfer material. When the sheet is nipped and conveyed, the contact surface of the transfer material conveying means with the transfer material is 1
This is achieved by heating after driving.

Further, according to the third invention of the present application, the above-mentioned object is to fix an unfixed image by forming an unfixed developer image on the transfer material and heating the transfer material while sandwiching and conveying the transfer material. A fixing device that melts the developer image and fixes it on the transfer material is provided, and the fixing device includes a transfer material transporting means for sandwiching and transporting the transfer material carrying the unfixed developer image, and the transfer material transporting means. An image forming apparatus having a transfer member and a heating unit for heating the unfixed developer image through
The heating means of the fixing device has a position for heating the contact surface side of the transfer material conveying means with the transfer material on the upstream side in the transfer material conveying direction with respect to the nipping portion of the transfer material conveying means, and a position of the transfer material conveying means. The transfer material is arranged at a position where heating is performed from the non-contact surface side with the transfer material, and the transfer material sandwiches the heating means arranged at a position where the contact surface side with the transfer material of the transfer material conveying means is heated. When being conveyed, the contact surface of the transfer material conveying means with the transfer material is 1
This is achieved by providing a control means set to drive the heating after the circuit is completed.

According to the fourth aspect of the present invention,
The above-mentioned object is arranged not only on the contact surface side of the transfer material conveying means with the transfer material, but also at the position where the heating means of the transfer material conveying means heats the transfer material before entering the holding portion of the transfer material conveying means. This is achieved by heating and driving the transfer material before and after the transfer material enters the holding portion.

Further, according to the fifth invention of the present application, the above-mentioned object is to fix an unfixed image by forming an unfixed developer image on the transfer material and heating the transfer material while nipping and transporting the transfer material. A fixing device that melts the developer image and fixes it on the transfer material is provided, and the fixing device includes a transfer material transporting means for sandwiching and transporting the transfer material carrying the unfixed developer image, and the transfer material transporting means. An image forming apparatus having a transfer member and a heating unit for heating the unfixed developer image through
The heating means of the fixing device is a position for heating the contact surface side of the transfer material conveying means with the transfer material on the upstream side in the transfer material conveying direction with respect to the nipping portion of the transfer material conveying means. The holding means of the device is provided at a position for heating the transfer material before the plunging, and the heating means is provided with a control means set to drive heating before and after the plunging of the transfer material into the sandwiching portion. Will be achieved.

According to a sixth aspect of the present invention,
The above object has a transfer material conveying means for sandwiching and conveying a transfer material carrying an unfixed developer image, and a heating means for heating the transfer material and the unfixed developer image via the transfer material conveying means, In a fixing device in which an unfixed developer image is melted and fixed on a transfer material by heating while sandwiching and transferring the transfer material, the transfer material conveying means makes contact with the transfer material when nipping and transferring the transfer material. This is achieved by driving the surface in the second lap at a slower speed than in the first lap.

Further, according to the seventh invention of the present application, the above-mentioned object is to fix an unfixed image by forming an unfixed developer image on the transfer material and heating the transfer material while nipping and transporting the transfer material. A fixing device that melts the developer image and fixes it on the transfer material is provided, and the fixing device includes a transfer material transporting means for sandwiching and transporting the transfer material carrying the unfixed developer image, and the transfer material transporting means. An image forming apparatus having a transfer member and a heating unit for heating the unfixed developer image through
Achieved by providing the transfer material conveying means with a control means set to drive the transfer material at a speed slower in the second lap than in the first lap of the contact surface with the transfer material when the transfer material is nipped and conveyed. To be done.

According to the eighth aspect of the present invention,
The above object has a transfer material conveying means for sandwiching and conveying a transfer material carrying an unfixed developer image, and a heating means for heating the transfer material and the unfixed developer image via the transfer material conveying means, In a fixing device that melts an unfixed developer image by heating it while sandwiching and transporting the transfer material to fix it on the transfer material, the outer peripheral length of the contact portion of the transfer material transport means with the transfer material is regulated. Is achieved by being longer than the length of the transfer material being used.

That is, in the first invention of the present application, the heating means is at least on the upstream side in the transfer material conveying direction of the transfer material conveying means with respect to the contact surface side of the transfer material conveying means with the transfer material. Since it is arranged at a heating position, the contact surface of the transfer material conveying means with the transfer material is directly heated, and the heat taken by the transfer material and the developer image is supplemented.

Further, in the second invention according to the present application, in addition to the heating means of the first invention, there is provided heating means for heating from the non-contact surface side of the transfer material conveying means with the transfer material, When the transfer material is nipped and conveyed, the heating means of the first aspect of the invention is driven to heat after the contact surface of the transfer material conveying means with the transfer material makes one round. Immediately compensates for the heat lost by the developer image, and the first lap and 2
Eliminates temperature change between the first and second laps.

Further, in the third invention of the present application, the fixing device is heated on the contact surface side of the transfer material conveying means with the transfer material on the upstream side in the transfer material conveying direction with respect to the nipping portion of the transfer material conveying means. And a heating means for heating from the non-contact surface side of the transfer material conveying means with the transfer material, and the contact surface side of the transfer material conveying means with the transfer material is controlled by the control means of the image forming apparatus. When the transfer material is nipped and conveyed, the heating means for heating is driven to heat after the contact surface of the transfer material conveying means with the transfer material makes one round, so that the transfer material and the developer image are captured within one round. Immediately compensates for the heat that is lost
Eliminates temperature change between the first and second laps.

Further, in the fourth invention of the present application, the heating means of the first invention is provided not only on the contact surface side of the transfer material conveying means with the transfer material but also on the sandwiching portion of the transfer material conveying means. It is arranged at a position to heat the transfer material before the plunging, and is heated and driven before and after the plunging of the transfer material into the nipping portion. Reduces the amount of heat taken from the transfer material conveying means.

Further, in the fifth invention of the present application, the fixing device is provided with not only the transfer material of the transfer material conveying means, which is in contact with the transfer material, but also the transfer material before being rushed into the nipping portion of the transfer material conveying means. Since the heating means is provided with heating means for heating, and the heating means is driven by the control means of the image forming apparatus before and after the transfer material enters the nip portion, the temperature difference between the transfer material and the transfer material conveying means becomes small, The amount of heat taken by the transfer material from the transfer material conveying means is reduced.

According to the sixth invention of the present application,
When the transfer material is nipped and conveyed, the transfer material conveying means is driven at a speed slower in the second rotation than in the first rotation of the contact surface with the transfer material, so that the image glossiness in the second rotation is not reduced. .

Further, in the seventh invention of the present application, when the transfer material conveying means of the fixing device is nipped and conveyed by the control means of the image forming apparatus, the transfer material conveying means makes one round of the contact surface with the transfer material. Since the second lap drives at a slower speed than the second lap, the image glossiness in the second lap is not reduced.

Further, in the sixth aspect of the present application, the length of the outer circumference of the contact portion of the transfer material conveying means with the transfer material is made longer than the prescribed length of the transfer material. For fixing, the contact surface of the transfer material conveying means with the transfer material is 1
Since the process is completed during the circumference, fixing is not performed by the portion where heat is taken by the transfer material, and uneven gloss does not occur.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) First, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. The image forming apparatus of the present embodiment is an electrophotographic printer similar to the conventional example as shown in FIG. 2, but differs from the conventional example in that a heater 16 is provided outside the fixing roller 10. In addition, the same reference numerals are given to the common parts with the conventional example, and the description is omitted.

FIG. 1 is a diagram showing a fixing device according to a first embodiment of the present invention. In FIG. 1, 10 is a fixing roller which is a transfer material conveying means. Thickness of multiple toner of four colors (several μm
In order to cope with this, an elastic layer of silicone rubber or the like is provided on a core metal of aluminum or the like of several tens of μm or more.

A pressure roller 11, which is a transfer material conveying means, is also arranged in pressure contact with the fixing roller 10, and the transfer material 5 is nipped and conveyed by the pressure contact portion while rotating with each other. Inside the pressure roller 11,
Since the halogen heater 15, which is a heating unit, is provided, the transfer material 5 and the unfixed developer image on the transfer material 5 are pressed and heated to be fixed and discharged.

Therefore, the heat of the fixing roller 10 is applied to the transfer material 5
In addition, the developer image on the transfer material 5 may be deprived of the toner, resulting in a decrease in temperature and a temperature difference between the first and second laps of the fixing roller 10.

Therefore, in this embodiment, the heater 16 is arranged as an auxiliary heating means on the transfer material rushing side of the surface of the fixing roller 10 for reasons such as thermal efficiency, and the silicone rubber on the surface of the fixing roller 10 is used. In order to prevent deformation and deterioration, the surface temperature of the fixing roller 10 is set to 200 ° C. or lower.

Then, the auxiliary heater 16 installed in the vicinity of the fixing roller 10 is turned on at the timing when the fixing roller 10 has completed one revolution, whereby the fixing roller 10 is turned on.
Heat the surface. As a result, the amount of heat taken by the transfer material 5 and the developer image is directly applied to the surface of the fixing roller 10 to suppress the change in the fixing temperature between the first and second rounds of the fixing roller 10, thereby preventing uneven gloss. .

The auxiliary heater 16 may be a halogen heater, a ceramic heater, a heating wire or the like.

A well-known CPU or the like may be used as the control means for the heater 15 and the heater 16, and the control means may be provided on the fixing device side or the image forming apparatus main body side. .

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 3 is a view showing a fixing device according to a second embodiment of the present invention. As shown in FIG. 3, in this embodiment, the heater 17 which is a heating means of the fixing roller 10 is attached to the fixing roller 10. It is provided outside to heat the surfaces of the transfer material 5 and the fixing roller 10.

The heater 17 sets the surface temperature of the fixing roller 10 to 170 ° C. and the surface temperature of the transfer material 5 to the melting point of the toner, for example, around 65 ° C.

As a result, in addition to the effects of the first embodiment, the temperature difference between the transfer material 5 and the fixing roller 10 becomes small, so that the amount of heat taken by the transfer material 5 from the surface of the fixing roller 10 can be made small, and the fixing roller can be made small. By suppressing the change in the fixing temperature between the first and second rounds of No. 10, uneven gloss can be prevented.

Furthermore, the temperature of the transfer material 5 suddenly rises during fixing, and the moisture contained in the transfer material 5 becomes water vapor,
For the same reason, it is possible to prevent the phenomenon that the toner before being fixed is blown off and the image is disturbed.

The heater may be a halogen heater, a ceramic heater, a heating wire or the like.

A known CPU or the like may be used as the control means for the heater 17, and the control means may be provided on the fixing device side or the image forming apparatus main body side.

(Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 4 is a drawing according to a third embodiment of the present invention. In FIG. 4, 18 is a fixing motor control circuit, 19 is a fixing motor, and the fixing motor 1
9, the fixing roller 10 is rotationally driven by using a known drive transmission means. The pressure roller 11
Is rotated by the fixing roller 10.

FIG. 5 shows a relationship between the gloss unevenness and the fixing speed when a paper passing experiment is performed. In this embodiment, the fixing speed is controlled based on this relationship.

That is, when the transfer material plunges into the fixing device,
The fixing motor control circuit 18 suppresses the fixing speed of the fixing roller 10 in the second lap rather than in the first lap so that even if the temperature decreases in the first lap, the fixing material is sufficient for the transfer material and the developer in the second lap. Applying sufficient heat to prevent uneven gloss.

The fixing motor control circuit as the control means may be arranged on the fixing device side or the image forming apparatus main body side.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 6 is a diagram showing a fixing device according to a fourth embodiment of the present invention. As shown in FIG. 6, the outer circumference of the fixing roller 10 of the present embodiment is larger than the prescribed length of the transfer material. It is getting bigger. In the case of an image forming apparatus that feeds A4 paper vertically, the outer circumference of the fixing roller 10 is 297 mm in the length of A4 paper.
It is better if it is larger. When this condition is satisfied, the transfer material is fixed within one revolution of the fixing roller 10, so uneven gloss can be prevented.

Further, when the transfer material is continuously fed, the peripheral length of the fixing roller, the peripheral speed, the paper interval, etc. are set so that the transfer material always rushes to the position where the fixing roller is provided, so that the fixing is uniform. Can be realized.

In each of the above-mentioned embodiments, the fixing roller is used as the transfer material conveying means of the fixing device, but it is disclosed in JP-A-63-313182 and JP-A-2-15787.
As disclosed in JP-A No. 8 and JP-A-4-44075 to 44083, a heat-resistant film is used as a transfer material conveying means, a heating means is provided on one side of the heat-resistant film, and a transfer material is provided on the other side. The present invention can also be applied to a fixing device of a type in which the transfer material is moved in contact with the transfer material along with the film to apply the thermal energy of the heating means to the transfer material and the developer image on the transfer material via the film.

[0055]

As described above, the first embodiment according to the present application is described.
According to the invention, since the heating means is arranged at a position for heating at least the contact surface side of the transfer material conveying means with the transfer material at the upstream side in the transfer material conveying direction with respect to the nipping portion of the transfer material conveying means, It is possible to supplement the heat taken by the material and the developer image and prevent uneven gloss.

According to the second invention of the present application,
In addition to the heating means of the first invention, a heating means for heating the transfer material conveying means from the non-contact surface side of the transfer material is provided, and the heating means of the first invention nips and conveys the transfer material. In this case, since the contact surface of the transfer material conveying means with the transfer material makes one revolution, the heating is driven, so that the heat taken by the transfer material and the developer image is immediately compensated for in one revolution. It is possible to prevent uneven glossiness by reducing the temperature difference between the second eye and the second round.

Further, according to the third invention of the present application, in the fixing device, the contact surface side of the transfer material conveying means with the transfer material is located on the upstream side in the transfer material conveying direction with respect to the nipping portion of the transfer material conveying means. A heating means for heating and a heating means for heating from the non-contact surface side of the transfer material conveying means with the transfer material are provided, and the contact surface side of the transfer material conveying means with the transfer material is controlled by the control means of the image forming apparatus. When the transfer material is nipped and conveyed, the heating means for heating the sheet is heated and driven after the contact surface of the transfer material conveying means with the transfer material makes one round. Immediately supplement the heat taken away, and the first lap and 2
It is possible to prevent uneven glossiness by eliminating the temperature change between the first and second rounds.

According to the fourth invention of the present application,
The heating means of the first invention is arranged not only on the contact surface side of the transfer material conveying means with the transfer material but also at a position for heating the transfer material before entering the holding portion of the transfer material conveying means. Since the heating is driven before and after the material rushes into the holding portion, the temperature difference between the transfer material and the transfer material conveying means becomes small, and the amount of heat taken by the transfer material from the transfer material conveying means can be reduced to prevent uneven gloss. it can. Furthermore, the temperature of the transfer material suddenly rises during fixing, and the water contained in the transfer material becomes water vapor.
It is also possible to prevent the phenomenon that the toner before being fixed is blown off and the image is disturbed.

Further, in the fifth aspect of the present invention, the fixing device is provided with not only the transfer material of the transfer material conveying means, which is in contact with the transfer material, but also the transfer material before being rushed into the nipping portion of the transfer material conveying means. Since the heating means is provided with heating means for heating, and the heating means is driven by the control means of the image forming apparatus before and after the transfer material enters the nip portion, the temperature difference between the transfer material and the transfer material conveying means becomes small, The amount of heat taken by the transfer material from the transfer material transporting means can be reduced to prevent uneven gloss. Further, it is possible to prevent a phenomenon in which the temperature of the transfer material suddenly rises at the time of fixing, the moisture contained in the transfer material becomes water vapor, and the toner before fixing is blown off to disturb the image.

According to the sixth invention of the present application,
When the transfer material is nipped and conveyed, the transfer material conveying means is driven at a speed slower in the second lap than in the first lap of the contact surface with the transfer material, so that the image glossiness in the second lap is lowered. It can prevent uneven gloss.

Further, in the seventh invention of the present application, when the transfer material conveying means of the fixing device is nipped and conveyed by the control means of the image forming apparatus, the transfer material conveying means makes one round of the contact surface with the transfer material. Since the second lap is driven at a slower speed than the second lap, it is possible to prevent the image glossiness in the second lap from decreasing and prevent uneven gloss.

Further, in the sixth aspect of the present application, the outer peripheral length of the contact portion of the transfer material conveying means with the transfer material is made longer than the prescribed length of the transfer material. For fixing, the contact surface of the transfer material conveying means with the transfer material is 1
Since the process is completed during the circumference, fixing is not performed by a portion where heat is taken by the transfer material, and uneven gloss can be prevented. Further, the fixing speed can be increased.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a fixing device according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram of an image forming apparatus according to the first embodiment of the present invention.

FIG. 3 is a schematic diagram of a fixing device according to a second embodiment of the present invention.

FIG. 4 is a block diagram of fixing motor control according to a third embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between fixing speed and glossiness in a third embodiment of the present invention.

FIG. 6 is a schematic diagram of a fixing device according to a fourth embodiment of the present invention.

FIG. 7 is a schematic diagram of a conventional image forming apparatus.

FIG. 8 is a diagram illustrating a wrapping effect.

[Explanation of symbols]

5 Transfer Material 10 Fixing Roller (Transfer Material Conveying Means) 11 Pressure Roller (Transfer Material Conveying Means) 15 Heater (Heating Means Heating from Non-Contact Surface Side of Transfer Material Conveying Means with Transfer Material) 16 Heater (Transfer Material Conveying) Heating means for heating from the contact surface side of the transfer material with the transfer material) 17 Heater (heating means for heating the transfer material conveying means and the transfer material from the contact surface side of the transfer material conveying means with the transfer material) 18 Fixing motor controller (transfer) Control means for speed of material conveying means)

Claims (8)

[Claims] 1. A transfer material carrying means for sandwiching and carrying a transfer material carrying an unfixed developer image, and a heating means for heating the transfer material and the unfixed developer image via the transfer material carrying means. In a fixing device that melts and fixes an unfixed developer image on a transfer material by heating the transfer material while sandwiching and transporting the transfer material, the heating means transports the transfer material more than at least the sandwiching portion of the transfer material transporting means A fixing device, characterized in that the fixing device is arranged at a position upstream of the transfer material conveying means for heating the contact surface side of the transfer material conveying means with the transfer material. 2. In addition to the heating means according to claim 1, a heating means for heating from a non-contact surface side of the transfer material conveying means with the transfer material is provided, and the heating means according to claim 1, The fixing device according to claim 1, wherein when the material is nipped and conveyed, heating is driven after the contact surface of the transfer material conveying means with the transfer material makes one round. 3. An image forming section for forming an unfixed developer image on a transfer material, and a fixing device for melting the unfixed developer image by heating while heating the transfer material while sandwiching and fixing it on the transfer material. The fixing device includes a transfer material conveying means for sandwiching and conveying a transfer material carrying an unfixed developer image, and a heating means for heating the transfer material and the unfixed developer image via the transfer material conveying means. In the image forming apparatus having the above, the heating means of the fixing device heats the contact surface side of the transfer material conveying means with the transfer material on the upstream side in the transfer material conveying direction with respect to the nipping portion of the transfer material conveying means. And a position for heating from the non-contact surface side of the transfer material conveying means with the transfer material, and a position for heating the contact surface side of the transfer material conveying means with the transfer material. When the transfer material is nipped and conveyed by the heated heating means, the transfer material is An image forming apparatus comprising: a control unit that is set to drive heating after the contact surface of the transfer unit with the transfer material makes one round. 4. The heating means according to claim 1 is arranged not only on the contact surface side of the transfer material conveying means with the transfer material, but also at a position for heating the transfer material before entering the holding portion of the transfer material conveying means. The fixing device according to claim 1, wherein the fixing device is provided and is heated and driven before and after the transfer material is thrust into the holding portion. 5. An image forming portion for forming an unfixed developer image on a transfer material, and a fixing device for melting the unfixed developer image by heating while heating the transfer material while sandwiching and fixing the image on the transfer material. The fixing device includes a transfer material conveying means for sandwiching and conveying a transfer material carrying an unfixed developer image, and a heating means for heating the transfer material and the unfixed developer image via the transfer material conveying means. In the image forming apparatus having the above, the heating means of the fixing device heats the contact surface side of the transfer material conveying means with the transfer material on the upstream side in the transfer material conveying direction with respect to the nipping portion of the transfer material conveying means. And a position for heating the transfer material before the transfer material is conveyed to the nipping portion of the transfer material conveying means, and the heating means is driven to heat the transfer material before and after the transfer material enters the nipping portion. To have a control means set to A characteristic image forming apparatus. 6. A transfer material carrying means for sandwiching and carrying a transfer material carrying an unfixed developer image, and a heating means for heating the transfer material and the unfixed developer image via the transfer material carrying means. In a fixing device that melts an unfixed developer image by heating it while sandwiching and transporting the transfer material to fix the transfer material on the transfer material, the transfer material transporting unit transfers the transfer material to the transfer material when sandwiching and transporting the transfer material. The fixing device is characterized in that the contact surface is driven at a slower speed on the second lap than on the first lap. 7. An image forming portion for forming an unfixed developer image on a transfer material, and a fixing device for melting the unfixed developer image by heating while heating the transfer material while sandwiching the transfer material. The fixing device includes a transfer material conveying means for sandwiching and conveying a transfer material carrying an unfixed developer image, and a heating means for heating the transfer material and the unfixed developer image via the transfer material conveying means. In the image forming apparatus having the above-mentioned configuration, the transfer material conveying means is set to be driven at a speed slower in the second lap than in the first lap of the contact surface with the transfer material when the transfer material is nipped and conveyed. An image forming apparatus comprising the control means described above. 8. A transfer material carrying means for sandwiching and carrying a transfer material carrying an unfixed developer image, and a heating means for heating the transfer material and the unfixed developer image via the transfer material carrying means. In a fixing device that melts an unfixed developer image by heating it while sandwiching and transporting the transfer material to fix it on the transfer material, the outer peripheral length of the contact portion of the transfer material transporting means with the transfer material is A fixing device characterized in that it is longer than the specified length of the transfer material.