JP2001083828A - Fixing device for both-side color printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently carry out fixing regardlessly of printing condition or printing environment in a fixing device for both-side color printer. SOLUTION: This device is provided with a fixing roll 19 that is heated by a halogen lamp 20 to a specific temperature and rotated, a pressure roll 22 for fixing unfixed image to a sheet incorporatively with the fixing roll 19 by being brought into a press contact with the fixing roll 19, being heated by a halogen lamp 23 to a specific temperature different from that of the fixing roll 19 and being rotated in a forward direction of the fixing roll, a temperature detecting means 21 for detecting the surface temperature of the fixing roll 19 to control the surface temperature of the fixing roll 19 and a temperature detecting means 24 for detecting the surface temperature of the pressure roll 22 to control the surface temperature of the pressure roll 22. Also the fixing roll 19 and the press roll 22 are made into the same constitution as each other.

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 color double-sided printing used in an electrophotographic color copying machine, a color printer, a color facsimile and the like.

[0002]

2. Description of the Related Art Conventionally, as a fixing device for color double-sided printing used in an electrophotographic color copying machine, a color printer, a color facsimile, etc., a fixing device for color single-sided printing is mainly used.

In general, a fixing device for printing on one side of a color includes a fixing roller having a heat source such as a halogen lamp or a fixing roller having a heat source such as a heating resistor in the roller itself, and a fixing roller facing the fixing roller. A pressure roller that is partially pressed, a driving unit that rotationally drives the fixing roller or the pressure roller or both the fixing roller and the pressure roller, and a temperature detection unit that detects and controls the surface temperature of the fixing roller. An unfixed image is fixed on the recording member by a heated fixing roller.

Here, in color fixing, in addition to the function of fixing an unfixed image, that is, a toner image, which is a role of monochrome fixing, to a recording member such as paper, two-color or three-color toner is completely melted. In addition, a function of finishing the surface of the toner with high gloss to develop color is required. for that reason,
The fixing control temperature is set higher than in the case of monochrome.

[0005] Silicone rubber is used for the fixing roller mainly because a completely melted toner flows on a core metal such as aluminum or steel so that the toner hardly expands and a stress acts on the entire toner. Further, in order to reduce the consumption of a release agent such as silicone oil, a multilayer rubber structure in which a fluorine rubber or a fluorine coat is applied as a barrier layer between silicone rubber layers is adopted.

On the other hand, as for the pressure roller, silicone rubber is provided on an aluminum or steel core so that a release agent such as silicone oil is consumed little, and the toner has a releasability at normal temperature. High fluorine rubber, fluorine coat, and fluorine tube are used, and each roller has a different configuration.

However, silicone rubber and fluororubber for color fixing have high heat resistance but low thermal conductivity, and the fixing roller having a fluorine coating on a core metal such as aluminum or steel for monochrome fixing has a heat capacity. The difference of
There is a disadvantage that it is difficult to control the temperature of the roller surface.

Further, in the fixing device for single-sided printing of a color, when the printing surface which has been fixed first passes through the fixing device again, the fixed toner is re-melted and does not wind around the pressure roller when the printing surface which has been fixed first passes through the fixing device again. Holes are formed in the paper transport guide and housing, etc., and cooling is performed so that the temperature of the pressure roller is lowered by air flow.

[0009]

By the way, in a fixing device for color double-sided printing using the fixing device for single-sided printing of color, there is no means for controlling the temperature of the pressure roller.
When the surface of the fixing roller reaches the control temperature, that is, when the warm-up is completed, the surface temperature of the pressure roller is rising, and the surface temperature of the pressure roller changes depending on the printing state. For example, in the case of intermittent printing, the space between the sheets as recording members is widened, and the heat of the heated fixing roller is transmitted to the pressing roller, so that the surface temperature of the pressing roller increases. Conversely, in continuous printing, since the space between the paper sheets as recording members is narrow, the heat of the heated fixing roller is not transmitted to the surface of the pressure roller. There is an unstable surface where the roller surface temperature decreases.

In other words, in controlling the surface temperature of only the fixing roller, poor printing of hot offset due to a rise in the surface temperature of the pressure roller during intermittent printing and poor printing of a cold offset due to a decrease in the surface temperature of the pressure roller during continuous printing are considered. Therefore, the temperature control range where good fixing can be obtained becomes narrow.

Further, since the surface layer of the pressure roller is made of a fluorine-based member which consumes a small amount of a release agent such as silicone oil and has a good toner releasability at room temperature, the surface temperature of the apparatus is reduced. When the surface temperature of the heating roller becomes about 110 ° C. or higher due to a rise, intermittent printing, or the like, the first fixed toner is re-melted by double-sided printing and wraps around the pressure roller to cause paper jam. As a countermeasure, the pressure roller is cooled by air flow by opening a hole in the paper transport guide and housing, but at cold start or in a low temperature environment, the pressure roller is too cold and cold offset by single-sided color printing. Fixing failure occurs.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device for color double-sided printing capable of performing satisfactory fixing regardless of printing conditions and printing environment.

[0013]

In order to solve this problem, a fixing device for double-sided color printing according to the present invention comprises a fixing roller which is heated to a constant temperature by a first heat source and rotates, and is pressed against the fixing roller. A pressure roller that is heated to a fixed temperature different from that of the fixing roller by the second heat source, rotates in a forward direction with the fixing roller, and cooperates with the fixing roller to fix an unfixed image on the recording member; First temperature detecting means for detecting the surface temperature of the fixing roller and controlling the surface temperature of the fixing roller, and second temperature detecting means for detecting the surface temperature of the pressing roller and controlling the surface temperature of the pressing roller And the fixing roller and the pressure roller have the same configuration.

Thus, the surface temperature of the fixing roller and the surface temperature of the pressure roller having the same configuration are controlled to be constant by the first heat source and the second heat source, respectively, regardless of the printing conditions and the printing environment. And good fixing can be performed.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to a first aspect of the present invention is directed to a fixing roller which is heated to a constant temperature by a first heat source and rotates, and which is pressed against the fixing roller and is pressed by the second heat source. And a pressure roller that rotates in a forward direction with the fixing roller and cooperates with the fixing roller to fix an unfixed image to the recording member, and detects the surface temperature of the fixing roller to perform the fixing. A first temperature detector for controlling the surface temperature of the roller; and a second temperature detector for detecting the surface temperature of the pressure roller to control the surface temperature of the pressure roller. This is a fixing device for color double-sided printing in which the pressure roller and the pressure roller have the same configuration, and has the effect that satisfactory fixing can be performed regardless of printing conditions and printing environment.

According to a second aspect of the present invention, in the first aspect, the surface temperature of the pressure roller is determined by the surface temperature of the fixing roller and the ambient temperature of the apparatus. This is a fixing device, and has the effect that satisfactory fixing can be performed regardless of printing conditions and printing environment.

According to a third aspect of the present invention, in the second aspect of the invention, the surface temperature of the pressure roller is equal to the second temperature.
When the heat source is turned off, only the fixing roller is controlled at a certain temperature by the first temperature detecting means at a certain ambient temperature, and the heat generated when the fixing roller and the pressure roller are rotated without passing through the recording member is controlled. This is a fixing device for color double-sided printing that is set to the saturation temperature of the pressure roller, and has the effect that satisfactory fixing can be performed regardless of printing conditions and printing environment.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the fixing roller and the pressure roller are arranged such that the fixing roller and the pressure roller extend outward from the metal core to form a silicone rubber layer. This is a fixing device for color double-sided printing having a multi-layer structure of a fluorine rubber layer and a silicone rubber layer, and has the effect that satisfactory fixing can be performed regardless of printing conditions and printing environment.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In these drawings, the same members are denoted by the same reference numerals, and duplicate description is omitted.

FIG. 1 is a sectional view showing an electrophotographic full-color printer provided with a fixing device for color double-sided printing according to an embodiment of the present invention. FIG. 2 is a fixing diagram for color double-sided printing according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing the apparatus, FIG. 3 is an explanatory view showing the results of surface temperature changes of the fixing roller and the pressure roller during continuous printing at a certain ambient temperature in the fixing apparatus for color double-sided printing of FIG. 2, and FIG. FIG. 5 is an explanatory view showing the results of surface temperature changes of a fixing roller and a pressure roller during intermittent printing at a certain ambient temperature in a fixing device for color double-sided printing, FIG. 5 is a cross-sectional view showing a conventional fixing device for color single-sided printing, FIG. 6 is an explanatory diagram showing the results of surface temperature changes of the fixing roller and the pressure roller in continuous printing at a certain ambient temperature in the fixing device for single-sided color printing of FIG. 5, and FIG.
FIG. 8 is an explanatory view showing the results of surface temperature changes of a fixing roller and a pressure roller during intermittent printing at a certain ambient temperature in a fixing device for color single-sided printing of FIG. 8; FIG. 9 is an explanatory diagram showing the saturation temperature of the pressure roller when left unattended, and FIG. 9 is an explanatory diagram showing the rubber configuration of the fixing roller and the pressure roller of the fixing device for color double-sided printing according to one embodiment of the present invention. 10 is an explanatory view showing the configuration of a pressure roller in the fixing device for single-sided printing of FIG.

The printer 1 shown in FIG. 1 has an exposure device 4 to which image data obtained by rasterizing each color dot data of cyan, magenta, yellow and black (CMYK) is input as a light emission signal. This exposure apparatus 4
Irradiation is performed with a laser that switches between light emission and light off for each dot in accordance with a light emission signal of image data. Further, in the printer 1, a photosensitive member 2 on which a latent image is formed is rotatably adjusted by three rollers.

In the vicinity of the photoconductor 2, a charging device 3 for uniformly charging the photoconductor 2 negatively is arranged. By irradiating the above-described laser to the uniformly charged photoconductor 2 from the exposure device 4, an electrostatic latent image is formed on the photoconductor 2.

A black developing device 8 for developing a black toner image, a cyan developing device 7 for developing a cyan toner image, and a magenta developing device 6 for developing a magenta toner image so as to be able to approach and separate from the photosensitive member 2 respectively. And four developing units, a yellow developing unit 5 for developing a yellow toner image.

These developing units 5, 6, 7 and 8 are provided with a photosensitive member 2
The black developing device contact / separation cam 8a, the cyan developing device contact / separation cam 7a, the magenta developing device contact / separation cam 6a, and the yellow developing device contact / separation cam 5a are respectively rotated. The photosensitive member 2 is pressed against the urging force. Then, the pressed developing devices 5, 6, 7, 8
The latent image is visualized by the toner supplied from the photoconductor 2, and a toner image is formed on the photoconductor 2.

As shown, a transfer belt 9 is provided in contact with the photosensitive member 2. The transfer belt 9 is also rotatably adjusted by three rollers. The transfer belt 9 is pressed against the photoconductor 2 and rotates around the photoconductor 2 in the forward direction. The toner image formed on the photoconductor 2 is transferred to the transfer belt 9 by electrostatic force. You.

The printer 1 is provided with a paper feeding device 10. A sheet P, which is a recording member, is stored in the sheet feeding device 10, and the sheet P is taken out one by one by a sheet feeding roller 11 and is conveyed along a sheet feeding path.

On the paper feed path, a timing roller 12 for starting rotation at the timing of the leading edge of the toner image and the leading edge of the sheet P, and pressing the sheet P to the transfer belt 9 to feed the sheet P onto the transfer belt 9 A transfer roller 13 that transfers the toner image onto the sheet P is provided.

A fixing device 14 for color double-sided printing is provided on the conveyance path of the sheet P behind the transfer roller 13. Then, the transferred toner image is fixed to the sheet P by passing the sheet P through the fixing device 14 for color double-sided printing.

In order to perform double-sided printing on the sheet P, a switchback section 16 for reversing the front and back of the sheet P is provided behind the fixing device 14 for color double-sided printing on the conveyance path. Then, from the switchback unit 16,
A conveyance path for double-sided printing, which joins the sheet P inverted by the switchback unit 16 with the conveyance path immediately before the timing roller 12, extends.

A switching member 17 for feeding the sheet P from the switchback section 16 to the double-sided printing conveyance path is provided at the start position of the double-sided printing conveyance path. A plurality of transport rollers 18 for transporting the sheet P are arranged on the duplex printing transport path.

At the rear end of the transport path, a tray 15 for discharging the sheet P on which the toner image has been transferred and fixed is provided.

Next, the printer 1 having such a configuration will be described.
The operation of will be described.

When the outer peripheral surface of the photoreceptor 2 rotating in the direction of the arrow is uniformly charged to a predetermined potential by the charging device 3, the photoreceptor 2 is irradiated with a laser from the exposure device 4 to generate an electrostatic latent image. Is formed.

The electrostatic latent image is developed as a yellow toner image by a yellow developing device 5 and held on a transfer belt 9 rotating in the direction of the arrow. Similarly, magenta and cyan toner images are developed on the photoreceptor 2 by the magenta 6 and cyan developing units 7, respectively, and are superimposed on the yellow toner image on the transfer belt 9 to form a full-color toner image. Is done.

On the other hand, a sheet P, which is a recording member, is fed from a sheet feeding device 10 by rotation of a sheet feeding roller 11 and is conveyed to a transfer roller 13 at a timing with a toner image by a timing roller 12, where a full color image is formed. The toner image is transferred.

Next, the sheet P is conveyed to the fixing device 14 for color double-sided printing, where the toner image is fused and fixed, and is discharged to the tray 15. When a black image is formed, a black developing device 8 containing black toner is used.
Is used.

In double-sided printing, the switchback unit 1
The sheet P is turned upside down by 6, and is conveyed by the conveyance roller 18 through the conveyance path for double-sided printing by the switching member 17 and returned to the timing roller 12. Thereafter, printing is performed in the same process as described above, and double-sided printing on the sheet P is performed.

Here, the fixing device 14 for color double-sided printing
Has a fixing roller 19 as shown in FIG.
Then, it is compressed by the fixing roller 19 and is
Is arranged.

The fixing roller 19 is driven to rotate, for example, counterclockwise (in the direction of arrow 28) by driving means. As described above, the fixing roller 19 is in pressure contact with the pressure roller 22, and rotates the pressure roller 22 clockwise (in the direction of arrow 29).
In order to keep the rotation constant, the material is coated with a material having a large friction coefficient (for example, silicone rubber).

The fixing roller 19 is desirably made of a material having a high thermal conductivity from the viewpoint of supplying heat to the toner, and the core metal is preferably made of, for example, aluminum or copper.

Inside the fixing roller 19, one or more halogen heater lamps 20 as a first heat source are provided. Note that a resistance heating element, an electromagnetic induction heating device, or the like may be used as the first heat source.

In the vicinity of the fixing roller 19, a temperature detecting device (first temperature detecting means) 21 for detecting the surface temperature of the fixing roller 19 for controlling the surface temperature is provided. Is applied to the fixing roller 19.

A cleaning roller 26 which presses the oil application roller 25 to clean the surface of the oil application roller 25, and an oil roller which is a toner release oil supply source for supplying toner release oil to the oil application roller 25. 27 are provided.

The oil application roller 25 is pressed against the fixing roller 19 and is driven at the same peripheral speed as the fixing roller 19. The cleaning roller 26 and the oil roller 27 are pressed by the oil application roller 25 so as to rotate following the oil application roller 25.

When there is little toner releasing oil on the surface of the oil applying roller 25, the oil releasing roller 27 is driven to rotate and the toner releasing oil is supplied to the oil applying roller 25. When the release oil is sufficient on the surface, the oil application roller 25 and the oil roller 27 slip due to the toner release oil, and the oil roller 27 does not rotate, so that the toner release oil is not supplied. In this way, oil is stably applied to the fixing roller 19.

Since the surface of the oil application roller 25 is set to be coarser than that of the fixing roller 19, the sheet P
The remaining toner that has not been fixed is moved from the fixing roller 19 to the oil application roller 25. The cleaning roller 26 is provided to remove the toner that has moved to the oil application roller 25 as described above. The surface of the cleaning roller 26 is covered with a rougher surface than the oil application roller 25, and for example, a felt, a nonwoven fabric, or the like is used.

Incidentally, a halogen heater lamp 23 serving as a second heat source is provided inside the pressure roller 22 in order to stably perform fixing even during color duplex printing.
This is because in color double-sided printing, similarly to the fixing roller 19, it is important to stabilize the surface temperature of the pressure roller 22.

FIGS. 6 and 7 show the conventional fixing device for color single-sided printing shown in FIG. 5 in which the pressure roller 22 without the second heat source is used for continuous printing and for the intermittent printing. The surface temperature change is shown.

As shown in FIG. 6, in the prior art, the completion of warming-up is determined by the surface temperature of the fixing roller 19, so that at the start of printing, the surface temperature of the pressure roller 22 is rising, that is, unstable. It turns out that it is a situation.
Also, in continuous printing, the temperature of the pressure roller 22 decreases, and it is predicted that the gloss of the fixed image will decrease and that a cold offset defect will occur.

Further, as shown in FIG. 7, in the related art, in intermittent printing, the temperature of the pressure roller 22 gradually increases, and hot offset and roller winding are predicted. Particularly, in the case of double-sided printing, the situation is further deteriorated because the warm paper once fixed passes through the fixing device 14.

The temperature of the pressure roller 22 at the time of completion of warming-up depends on the environment.
Under the influence of the cooling by the air flow that is compatible with the double-sided fixing, several sheets from the first sheet are reduced in gloss and defective in the cold offset.

From the above situation, in order to stabilize the surface temperature of the pressure roller 22, a second heat source is provided to control the temperature. As the second heat source, a resistance heating element, an electromagnetic induction heating device, or the like may be used as in the case of the fixing roller 19.

In the vicinity of the pressure roller 22, a second temperature detecting device (second temperature detector) for detecting the temperature of the outer peripheral surface of the pressure roller 22 regardless of whether the pressure roller 22 is rotating or stopped. Temperature detecting means) 24 is provided.

Here, the control temperature of the surface of the pressure roller 22 is determined as follows.

FIG. 8 shows the temperature change of the pressure roller 22 when the temperature of the fixing roller 19 is controlled at a certain environmental temperature, and the rotation is driven to stand.

As shown in the figure, it can be seen that the surface temperature of the pressure roller 22 gradually rises and reaches a certain saturation temperature. At this time, the surface temperature difference between the fixing roller 19 and the pressure roller 22 is a heat loss in the fixing device, and the smaller the temperature difference, the better the thermal efficiency. That is, when fixing is performed within a limited heat amount range of the heat source, if the heat loss is large, the heat amount given to the recording member, that is, the sheet and the toner is reduced, and fixing failure such as cold offset occurs. On the other hand, when the heat amount of the heat source is considerably large, the ON-O
Since FF cannot be performed, temperature control is difficult, and in a region where heat loss is small, fixing failure such as hot offset occurs.

Therefore, the surface control temperature of the pressure roller 22 is preferably controlled at this saturation temperature from the viewpoint of thermal efficiency and also from the decrease in the amount of heat of the heat source. Moreover, the saturation temperature of the pressure roller 22 is experimentally determined by the ambient temperature of the fixing device 14 and the control temperature of the fixing roller 19, and is uniquely determined.

That is, the surface temperature of the pressure roller 22 during the fixing operation is controlled by turning off the halogen heater lamp 23 and controlling only the fixing roller 19 to a constant temperature by the temperature detecting means 21 at a certain ambient temperature. The saturation temperature of the pressure roller 22 when the fixing roller 19 and the pressure roller 22 are rotated without passing through P is set.

If the surface temperature of the pressure roller 22 is maintained at this saturation temperature when the fixing device 14 for color double-sided printing rises, the temperature always changes at this temperature when the sheet P does not pass. When the surface temperature of the pressure roller 22 decreases, heat is supplied from the halogen heater lamp 23, so that the surface temperature of the pressure roller 22 is stabilized at the set saturation temperature.

Further, since the saturation temperature of the pressure roller 22 is higher than the surface temperature of the pressure roller 22 in the conventional fixing device, the structure of the pressure roller 22 as shown in FIG. From the core metal 30 toward the outside,
In the configuration of the heat-resistant silicone rubber 31, the fluorine tube, and the fluorine-based member 32 such as fluorine rubber or fluorine coat, winding occurs due to re-melting of the toner.
Therefore, it is necessary that the configuration of the pressure roller 22 has a good toner releasability even at a high temperature, that is, the same configuration as the fixing roller 19. FIG. 9 shows the configuration.

In FIG. 9, the core 30 is desirably made of a material having a high thermal conductivity from the viewpoint of supplying heat to the toner. The core 30 is preferably made of, for example, aluminum or copper. Further, from the core metal 30 toward the outside, a silicone rubber layer 31 having high heat resistance, a fluorine rubber layer 32 for preventing the release oil from penetrating into the silicone rubber layer 31 to reduce oil consumption, and a toner releasing property. It is composed of a high and smooth silicone rubber layer 33.

By the way, the pressing roller 22 is
9 is driven to rotate by the friction with the arrow 9. When the sheet P enters between the pressure roller 22 and the fixing roller 19, there is a risk that the pressure roller 22 slips with respect to the fixing roller 19 to cause a conveyance failure of the sheet P. Therefore, it is desirable that each of the pressure roller 22 and the fixing roller 19 has a sufficient length of the non-sheet passing area (the area where the sheet P is not conveyed). Alternatively, it is preferable that the end of the fixing roller 19 is coated with a material having a low toner releasability, that is, a material having a high friction coefficient, so that a sufficient driving force is transmitted to the pressure roller 22.

Next, the operation of the fixing device 14 for color double-sided printing having such a configuration will be described.

In the fixing device 14, the fixing roller 19 is rotated in the direction of arrow 28 by a driving means such as a motor. As a result, the pressure roller 22 is driven to rotate in the direction of the arrow 29.

The fixing roller 19 and the pressure roller 22 are heated by heat from the halogen heater lamps 20 and 23, respectively. At this time, the fixing roller 19 and the pressure roller 2
2 is heated while being adjusted by the temperature detecting devices 21 and 24 near the pressure contact portion (nip portion) formed by the fixing roller 19 and the pressure roller 22 in order to avoid uneven gloss and poor fixing. Then, the fixing roller 19 and the pressure roller 22
After both of the surface temperatures reach the control temperature, the unfixed toner on the sheet P conveyed in the direction of the arrow 34 is applied to the fixing roller 19 at the nip formed by the fixing roller 19 and the pressure roller 22. The fixing roller 19 is melted by heat in contact with the pressure roller 22, and is further fixed on the sheet P by a pressure contact force between the fixing roller 19 and the pressure roller 22.

When the fixing is completed, the halogen heater lamps 20 and 23 and the driving motor are immediately turned off, and the rotation of the fixing roller 19 and the pressure roller 22 is stopped. While the apparatus is stopped, the apparatus enters a standby mode, in which the temperature of the fixing roller 19 is adjusted to a predetermined temperature, which is the temperature detecting device 21, and the temperature of the pressure roller 22 is also adjusted to the predetermined temperature by the temperature detecting device 24.

FIGS. 3 and 4 show the results of temperature control of the pressure roller 22 in continuous printing and intermittent printing by the color duplex printing fixing device 14 of the present embodiment.

Here, it can be seen that in the case of continuous printing, the surface temperature of the pressure roller 22 decreases at an initial stage, but recovers thereafter and is stable. In intermittent printing, since the saturation temperature is originally set at the saturation temperature, the surface temperature of the pressure roller 22 is stable without increasing.

As described above, according to the fixing device for color double-sided printing of the present embodiment, the surface temperatures of the fixing roller 19 and the pressure roller 22 having the same configuration are adjusted by the halogen heater lamp 20 and the halogen heater lamp. Since each is controlled to be constant by the reference numeral 23, good fixing can be performed regardless of printing conditions and printing environments.

[0070]

As described above, according to the present invention, the surface temperatures of the fixing roller and the pressure roller having the same configuration are controlled to be constant by the first heat source and the second heat source, respectively. Therefore, an effective effect that good fixing can be performed irrespective of printing conditions and printing environment is obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an electrophotographic full-color printer including a fixing device for color double-sided printing according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a fixing device for color double-sided printing according to an embodiment of the present invention;

FIG. 3 is an explanatory diagram showing the results of surface temperature changes of a fixing roller and a pressure roller in continuous printing at a certain ambient temperature in the fixing device for color double-sided printing of FIG. 2;

FIG. 4 is an explanatory diagram showing the results of surface temperature changes of a fixing roller and a pressure roller during intermittent printing at a certain ambient temperature in the fixing device for color double-sided printing in FIG. 2;

FIG. 5 is a cross-sectional view showing a conventional fixing device for color single-sided printing.

FIG. 6 is an explanatory diagram showing the results of surface temperature changes of a fixing roller and a pressure roller during continuous printing at a certain ambient temperature in the fixing device for color one-sided printing of FIG. 5;

FIG. 7 is an explanatory diagram showing the results of surface temperature changes of a fixing roller and a pressure roller during intermittent printing at a certain ambient temperature in the fixing device for color one-sided printing of FIG. 5;

FIG. 8 is an explanatory diagram showing the saturation temperature of the pressure roller when the roller is driven and left in the fixing device for single-sided printing of FIG. 5;

FIG. 9 is an explanatory diagram showing a rubber configuration of a fixing roller and a pressure roller of the fixing device for color double-sided printing according to one embodiment of the present invention.

10 is an explanatory diagram showing a configuration of a pressure roller in the fixing device for color single-sided printing of FIG. 5;

[Explanation of symbols]

 Reference Signs List 14 Fixing device for double-sided printing 19 Fixing roller 20 Halogen heater lamp (first heat source) 21 Temperature detecting device (First temperature detecting means) 22 Pressure roller 23 Halogen heater lamp (Second heat source) 24 Temperature detecting device (Second temperature detecting means) 30 core metal 31 silicone rubber layer 32 fluorine rubber layer 33 silicone rubber layer P sheet (recording member)

Claims (4)

[Claims] A fixing roller which is heated to a constant temperature by a first heat source and rotates; and which is pressed against the fixing roller and is heated to a constant temperature different from the fixing roller by a second heat source. A pressure roller that rotates in a forward direction to fix an unfixed image on a recording member in cooperation with the fixing roller; and a first roller that detects a surface temperature of the fixing roller and controls a surface temperature of the fixing roller. Temperature detecting means, and second temperature detecting means for detecting the surface temperature of the pressure roller to control the surface temperature of the pressure roller, wherein the fixing roller and the pressure roller are similar to each other. And a color double-sided printing and fixing device. 2. The fixing device according to claim 1, wherein the surface temperature of the pressure roller is determined by the surface temperature of the fixing roller and the ambient temperature of the apparatus. 3. The surface temperature of the pressure roller is controlled by turning off the second heat source and controlling only the fixing roller to a constant temperature by the first temperature detecting means at a certain ambient temperature. 3. The fixing device for double-sided color printing according to claim 2, wherein the saturation temperature of the pressure roller when the fixing roller and the pressure roller are rotated without passing through a recording member is set. 4. The fixing roller and the pressure roller,
The fixing device for color double-sided printing according to any one of claims 1 to 3, wherein the fixing device has a multilayer structure of a silicone rubber layer, a fluorine rubber layer, and a silicone rubber layer from the core metal toward the outside. .