JP2002091211A - Fixing device and image forming device provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device capable of improving an image quality, by preventing the difference of glossiness on the fixing image derived from such as fixing numbers, or amid machines and the image forming device equipping this fixing device. SOLUTION: This fixing device is provided with a glossiness detecting means 16 for detecting the glossiness on a surface of an output image on recording material P after fixation, and a controlling means being set so as to change fixating condition so that the glossiness being detected by the glossiness detecting means 16 becomes the specified glossiness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for fixing an unfixed image on the recording material by heating and pressing the recording material holding the unfixed image while nipping and conveying the recording material between a fixing member and a pressing member. The present invention relates to a fixing device for forming an image and an image forming apparatus including the image forming device.

[0002]

2. Description of the Related Art As a fixing device provided in a conventional image forming apparatus, for example, a fixing device having a configuration like a fixing device 5 shown in FIG. 9 is known.

[0005] As shown in detail in FIG. 9, a fixing device 105 includes a fixing roller 151 serving as a rating member, which is rotatably disposed.
A pressure roller 152 serving as a pressure member that rotates while being pressed against the fixing roller 151; a release agent application device 153 serving as a release agent supply / application unit;
155. Fixing roller 151
Inside the pressure roller 152, heaters 156 and 157 such as halogen lamps are provided, respectively. or,
Thermistors 158 and 159 are disposed so as to be in contact with the fixing roller 151 and the pressure roller 152, respectively.
The temperature of the surface of the fixing roller 151 and the pressure roller 152 is adjusted by controlling the voltage of the fixing roller 151 and the pressure roller 152. In this state, when the paper is conveyed, the fixing roller 151
And the pressure roller 152 rotate at a constant speed, and the fixing roller 1
Silicone oil is applied as a release agent to the surface of the paper 51, and when the paper P passes between the fixing roller 151 and the pressure roller 152, the paper P is pressed and heated at a constant pressure and temperature from both sides. The unfixed toner image on the paper surface is melted and fixed, and a full-color image is formed on the paper P. The paper P on which the image has been fixed is pressed by the lower separation claw 168 into the pressure roller 1.
52 and is discharged outside the machine.

[0004] The fixing roller used in the fixing device 105 described above is coated with a material having good releasability, such as fluorine resin or silicone rubber, and having excellent heat resistance and abrasion resistance. Has formed. For example, when the image forming apparatus places a high priority on image quality, such as a color copying machine using an electrophotographic system, a fixing roller 151 having a silicone rubber outer layer is often used. . This silicone rubber is slightly inferior in release property to fluororesin, but when silicone oil is applied as a release agent, the releasability is improved as compared to fluororesin.

[0005]

However, in the above-described conventional image forming apparatus, the following problem may occur.

First, in a thermal fixing device of a copying machine, heat is applied to a recording material at the time of fixing to fix the recording material.
The surface temperature of the fixing roller after the fixing is reduced. Then, a temperature decrease sensor on the surface of the fixing roller is detected by a temperature detection sensor in contact with the surface of the fixing roller, and based on the output, a heat source such as a halogen heater inside the fixing roller is turned on to supply heat to the fixing roller.

As a result, the surface temperature of the fixing roller is restored to the initial temperature, but a time delay occurs while heat from the heat source reaches the surface of the fixing roller. Further, in a machine having a large number of copies per unit time, the heat supply tends to catch up and the temperature drop tends to be larger. As a result, there is a possibility that the output image at the time when the temperature is not lowered at the beginning of the copy and the output image at the time when the temperature is lowered have different fixing properties, and the gloss of the output image may be different.

[0008] In addition, the initial fixing property also includes a temperature control temperature, a contact pressure of a temperature detection sensor, a pressing force between a fixing roller and a pressing roller,
Due to errors in the rotation speed of the fixing roller, the supply amount of the release agent, and the like, an error in fixability occurs for each machine, and as a result, the gloss of the output image may be different.

In addition, if the fixing roller is used for a long period of time, the surface of the fixing roller is deteriorated so that the unevenness becomes large, the surface of the temperature detecting sensor becomes dirty, and the amount of the release agent applied becomes large due to wear of parts. As a result, the gloss of the output image may be different between the same machine at the beginning of use and after a long use.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fixing device capable of preventing a difference in gloss of a fixed image due to the number of sheets to be fixed, a difference between machines, and the like, and improving image quality, and an image forming apparatus provided with the fixing device. I do.

[0011]

According to the present invention, an object of the present invention is to provide a fixing member and a pressing member which are pressed against each other and rotate, and a recording material for carrying an unfixed image is fixed by the fixing member and the pressing member. In a fixing device in which the unfixed image is fixed to the recording material by heating and pressing while nipping and conveying to form a fixed image, a fixed image gloss detecting a glossiness of a surface of the fixed image on the recording material after fixing is performed. The first aspect of the present invention is achieved by the first invention including a detection unit and a control unit configured to change a fixing process condition so that the glossiness detected by the fixed image gloss detection unit becomes a predetermined glossiness.

Further, according to the present application, the object is to provide a recording material having an unfixed image formed in accordance with a document image, comprising a fixing member and a pressure member which rotate in pressure contact with each other. In a fixing device in which the unfixed image is fixed on the recording material by applying heat and pressure while being nipped and conveyed by a pressing body to form a fixed image, the glossiness of the surface of the fixed image on the recording material after fixing is detected. Fixed image gloss detection means, original image gloss detection means for detecting the glossiness of the original image, and a difference between the glossiness detected by the glossiness detection means and the glossiness detected by the original image glossiness detection means. The present invention is also achieved by the second invention including a control unit configured to change the fixing processing conditions so as to achieve the predetermined glossiness.

Further, according to the present invention, the above object is achieved in the first invention or the second invention, wherein the fixed image gloss detecting means or the original image gloss detecting means is provided for detecting the total reflection light from the fixed image or the original image. This is also achieved by the third invention in which the ratio of the specular reflection light is detected as the glossiness.

According to the present application, the above object is achieved by any one of the first to third inventions, wherein the control means comprises:
The present invention is also achieved by the fourth invention in which the fixing processing conditions are set so as to change the glossiness detected by the gloss detection means to the predetermined glossiness during the continuous fixing process.

Further, according to the present application, the above object is achieved by the fifth invention in any one of the first to fourth inventions, wherein the control means is capable of changing a fixing speed as a fixing processing condition. Is also achieved.

According to the present application, the above object is achieved by any one of the first to fifth inventions, wherein the control means comprises:
This is also achieved by the sixth invention in which the fixing temperature can be changed as the fixing processing condition.

Further, according to the present application, the above object is achieved in any one of the first to sixth inventions, wherein the control means is capable of changing a pressing force by the fixing body and the pressing body as a fixing processing condition. This is also achieved by the seventh invention.

Further, according to the present application, the object is to provide an image forming apparatus for recording an image formed by a series of image forming processes on a recording material, wherein the image forming apparatus is any one of the first to seventh inventions. The present invention is also attained by the eighth invention including the fixing device of (1).

[0019]

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.

FIG. 1 is a sectional view showing a schematic configuration of a four-drum laser beam printer (hereinafter, referred to as a printer) as an example of an image forming apparatus according to the present embodiment. Such a printer is an image forming apparatus having a plurality of optical scanning units as shown in FIGS.

As shown in FIG. 1, such a printer is an image forming means comprising a developing device and the like around an electrophotographic photosensitive member (hereinafter referred to as a "photosensitive drum") as a latent image carrier. Four image forming stations are provided, and the image on the photosensitive drum formed in each image forming station is transferred to a recording material such as paper (hereinafter, referred to as paper) on a transport unit that moves and passes adjacent to the photosensitive drum. (Hereinafter simply referred to as paper).

As shown in FIG. 2, photosensitive drums 1a, 1b, 1c, and 4d are formed on image forming stations Pa, Pb, Pc, and Pd for forming images of magenta, cyan, yellow, and black, respectively. 1d is arranged, and each photosensitive drum is rotatable in the direction of the arrow.
Further, around the photosensitive drums 1a, 1b, 1c, 1d, chargers 12a, 12b, 12c, 12d, developing devices 2a, 2b, 2c, 2d, and cleaners 4a, 4d.
b, 4c, and 4d are sequentially arranged along the rotation direction of the photosensitive drum, and a transfer unit 3 is provided below each photosensitive drum.
Are arranged. The transfer section 3 has a transfer belt 31 as a recording material conveying means common to each image forming station and transfer chargers 3a, 3b, 3c, 3d.

In the printer as described above, the paper P supplied from the paper supply cassette 61 as the recording material supply means shown in FIG. 1 is supported on the transfer belt 31 and conveyed to each image forming station. The toner images of the respective colors formed thereon are sequentially transferred. When the transfer process is completed, the paper P is separated from the transfer belt 31 and is conveyed to the fixing device 5 by the conveyance belt 62 serving as a recording material guiding unit.

The fixing device 5, as shown in detail in FIG.
A fixing roller 51 serving as a fixing member rotatably disposed, a pressure roller 52 serving as a pressing member which rotates while being pressed against the fixing roller 51, a release agent applying device 53 serving as a release agent supply / applying means, The configuration has roller cleaning devices 54 and 55. Heaters 56 and 57 such as halogen lamps are provided inside the fixing roller 51 and the pressure roller 52, respectively. The thermistors 58 and 59 are disposed so as to be in contact with the fixing roller 51 and the pressing roller 52, respectively.
6. The temperature of the surfaces of the fixing roller 51 and the pressure roller 52 is adjusted by controlling the voltage to the heater 57. In this state, when the paper is conveyed, the fixing roller 51 and the pressure roller 52 rotate at a constant speed, silicone oil is applied as a release agent to the surface of the fixing roller 51, and the paper P When passing between the pressure roller 52 and the front and back surfaces, the unfixed toner image on the paper surface is melted and fixed by pressing and heating at a constant pressure and temperature from the front and back surfaces, and the full-color image is formed on the paper P. Is formed. The paper P on which the image has been fixed is separated from the pressure roller 52 by the lower separation claw 68 and discharged out of the apparatus.

The fixing roller used in the fixing device 5 as described above is coated with a material having good releasability, such as fluorine resin or silicone rubber, and having excellent heat resistance and abrasion resistance. Has formed. For example, when the image forming apparatus places a high priority on image quality, such as a color copying machine using an electrophotographic method, a fixing roller 51 in which silicone rubber is used as an outer layer of the roller is often used. . This silicone rubber is slightly inferior in release property to fluororesin, but when silicone oil is applied as a release agent, the releasability is improved as compared to fluororesin.

As shown in FIG. 4, the printer according to the present embodiment is provided with a glossiness detection means 16 as a fixed image glossiness detection means for detecting the glossiness of the surface of the output image (fixed image) at the discharge position after fixing. CPU as control means
(Not shown), as shown in the flowchart of the fixing condition change control in FIG. 5, the control is performed such that the optimum fixing condition is set in accordance with the glossiness of the output image surface detected by the glossiness detecting means 16. .

FIG. 4 shows the gloss detecting means 16 of this embodiment.
The measurement is performed by the method specified in JISZ8741. In other words, the measurement method is such that a light beam having a specified opening angle is incident on the output image surface at a specified incident angle, and the light beam having a specified opening angle reflected in the mirror reflection direction is measured by the light receiver.

In FIG. 4, a light beam irradiated by the irradiation light source 108 passes through a lens 110 and is incident on the recording material P at an angle ∂. Then, the light beam reflected in the mirror reflection direction is detected by the light receiver 109 through the lens 110. By arranging this output image glossiness detecting means between the fixing device of FIG. 1 and the paper discharge tray, the glossiness of the output image surface can be detected. In this embodiment and all other embodiments described later, the surface gloss was detected with an incident angle ∂ of 600.

In the present embodiment, as shown in FIG. 5, first, at least three or more copies are set on the operation screen (S101), and an image is formed by pressing a copy button (S102). Then, fixing is performed by the fixing device (S103).

Then, while the recording material is discharged onto the discharge tray after fixing, the glossiness G1 of the output image for one day is first detected by the glossiness detection means 16 shown in FIG. 4 (FIG. 4). S104).

Next, similarly, the output image is conveyed by forming the second image continuously (S105, S106), and similarly, the gloss G2 of the second output image is detected by the gloss detecting means 16 similarly. (S107).

Next, the CPU calculates the change rates of the gloss levels G1 and G2 of the first and second output images (S108).
When a change is detected, the pressing force of the fixing roller and the pressure roller is controlled so as to correct the change according to the change rate (S109, S110).

For example, if the change in glossiness is low, the above-mentioned pressing force is increased. Conversely, if the glossiness is high, the above-mentioned pressing force is reduced. As the pressure changing means for changing the pressing force, for example, a shaft provided with an eccentric cam is brought into contact with a sheet metal on which a pressing spring is fixed (not shown), and the pressing force is varied by rotating the eccentric cam. can do.

Then, the glossiness Gn of the output image after forming the n-th image is similarly detected (S111 to S11).
3) The gloss Gn of the n-th sheet and the gloss G of the (n-1) th sheet
Similarly, the CPU calculates the rate of change from n-1 (S11).
4) Feeding back to the control of the pressing force again (S
115, S116). This is sequentially repeated for each image formation (S117), and when the specified number of images have been formed, the pressing force returns to the initial state (S118). In this manner, the time delay due to the heat supply can be compensated for by the variable pressing force, and the output image at the time when the temperature has not decreased at the initial time during continuous copying and the output image at the time when the temperature has decreased have been reduced. The change in gloss could be made smaller than before.

Since the rate of change of the output image and the rate of change of the pressing force vary depending on the configuration of the fixing device and the toner material, it is necessary to set each for each model.

(Second Embodiment) Next, a second embodiment of the present invention will be described. The description of the same configuration as that of the first embodiment is omitted.

In the present embodiment, an image forming apparatus similar to that of the first embodiment is used to eliminate the difference in the glossiness of the output image with the machine.

As described above, the glossiness of the output image varies from machine to machine due to various setting errors and the like. In the present embodiment, as the output image glossiness adjustment mode,
The control as shown in FIG. 6 was performed.

In FIG. 6, first, using the same image forming apparatus as in the first embodiment, an image pattern in which toner is uniformly applied on the entire surface is output (S202). After completion of the fixing (S203), the glossiness Gp at that time is detected by the image glossiness detection means (S204).

Then, the difference between the value of the detected gloss Gp and the value of the specified gloss Gr is obtained, and the pressure is finely adjusted in accordance with the difference (S205, S206, S20).
7).

That is, when Gp <Gr, the pressing force is increased,
In the case of Gp> Gr, the pressure was weakened, and control was performed so as to match the default value for each model. The value of the fine adjustment of the pressing force varies depending on the configuration of the fixing device and the toner material. Basically, by performing such control at the time of shipping or installation of the device, any device can be adjusted to the default value.

The fine adjustment can be performed not only by the pressing force but also by adjusting the temperature adjustment temperature, the fixing speed, and the like as the fixing conditions.

(Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIGS. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected.
The description is omitted.

In this embodiment, similarly to the first embodiment and the second embodiment, a glossiness detecting means 1 is provided on the discharge side of the fixing device.
In the image forming apparatus provided with the image forming apparatus 6, glossiness detecting means 108 to 1 for detecting the glossiness of the original as shown in FIG.
10 is provided to control so as to correct the difference in glossiness between the document and the output image.

7 and 8, when the copy key of the operation unit is pressed (S301), a pre-scanning process for forming an image is started, and the irradiation light sources 103 and 108 are placed on the platen 102. The original 101 is irradiated.

The light reflected from the original 101 by the irradiation light source 103 is reflected by the imaging element array 104 and the infrared cut filter 1.
05 and CCD (contact color sensor CCD) 1
06 and is imaged. On the other hand, the reflected light from the document 101 by the irradiation light source 108 passes through the condenser lens 110 and reaches the light receiver 109.

Then, the optical system unit 107 is
While moving in the direction of arrow C, the platen 102
The upper document 101 is scanned.

Then, based on the image information read by the CCD 106, a document range, an optimum document irradiation light amount, and the like are calculated and determined. Further, based on the image information read by the light receiver 109, the reflected light is converted into a gloss value (gloss) by a gloss value conversion circuit according to a control device (processing circuit), and the entire screen of the original 101 is displayed. The maximum value in the calculation is calculated by a gross maximum calculation circuit (S302). And CC
The image information read in D106 is subjected to arithmetic processing and sent to a printer.

In the printer, the image is formed based on the image information as described above (S303). After the fixing is completed (S304), the glossiness of the output image is detected by the glossiness detecting means 16 (S305). . Here, the glossiness Gr of the document and the glossiness Gp of the output image are compared (S
306), according to the difference between the values, fine adjustment of the pressing force is performed in the fixing unit, and when Gp> Gr, the pressing force is increased and Gp <G
In the case of r, the pressure was weakened, and control was performed so as to match the default value for each model (S307, S308).

In this way, even if the gloss of the output image is reduced due to the deterioration of the fixing member or the like, the gloss can be corrected by changing the pressing force. In addition, the same image gloss as in the initial stage can be maintained.

The fine adjustment can be performed not only by the pressing force but also by adjusting the temperature adjustment temperature and the fixing speed as fixing conditions.

[0053]

As described above, according to the first aspect of the present invention, the fixing processing conditions are changed by the control means so that the glossiness detected by the fixed image gloss detection means becomes the predetermined glossiness. Therefore, it is possible to prevent a difference in the gloss of the fixed image due to the number of sheets fixed, between the units, and the like, and to improve the image quality.

According to the second invention of the present application,
The control unit changes the fixing processing conditions so that the difference between the glossiness detected by the fixed image gloss detection unit and the glossiness detected by the document image gloss detection unit becomes a predetermined glossiness. It is possible to prevent a difference in gloss of a fixed image due to a gap or the like, thereby improving image quality.

Further, according to the third aspect of the present invention, the glossiness detected by the fixed image gloss detection means or the glossiness detected by the fixed image gloss detection means and the glossiness of the original image are controlled by the control means. Since the fixing processing conditions are changed so that the difference between the glossiness detected by the detection means and the glossiness becomes a predetermined glossiness, it is possible to prevent a difference in glossiness of a fixed image due to a fixed number of sheets, an inter-machine, or the like, and improve image quality. Can be.

According to the fourth invention of the present application,
During the continuous fixing process, the control unit determines whether the gloss detected by the fixed image gloss detecting unit or the difference between the gloss detected by the fixed image gloss detecting unit and the gloss detected by the document image gloss detecting unit. Since the fixing processing conditions are changed so as to achieve the predetermined glossiness, it is possible to prevent a difference in gloss of the fixed image due to the number of fixed images, between apparatuses, and the like during the continuous fixing processing, and to improve the image quality.

Further, according to the fifth aspect of the present invention, the glossiness detected by the fixed image gloss detection means or the glossiness detected by the original image gloss detection means is increased or decreased by the control means. Since the fixing speed is changed so as to be faster or slower, it is possible to prevent a difference in the gloss of the fixed image due to the number of sheets to be fixed or between the apparatuses, and to improve the image quality.

According to the sixth aspect of the present invention,
The control unit changes the glossiness detected by the fixed image gloss detection unit or the fixing temperature to be lower or higher as the glossiness detected by the original image gloss detection unit is larger or smaller.
It is possible to prevent a difference in gloss of the fixed image due to a difference between the apparatuses, and to improve the image quality.

Further, according to the seventh aspect of the present invention, the glossiness detected by the fixed image gloss detection means or the glossiness detected by the original image gloss detection means is increased or decreased by the control means. Since the pressure applied by the fixing body and the pressing body is changed to be lower or higher as much as possible, it is possible to prevent a difference in the gloss of the fixed image due to the number of sheets to be fixed or between the apparatuses, and to improve the image quality.

According to the eighth invention of the present application,
The glossiness detected by the fixed image gloss detection means or the difference between the glossiness detected by the fixed image gloss detection means and the glossiness detected by the document image gloss detection means becomes the predetermined glossiness. Since the fixing processing conditions are changed as described above, it is possible to prevent the difference in gloss of the fixed image due to the number of fixed images, between the apparatuses, and the like, and to improve the image quality.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of an image forming unit of the image forming apparatus of FIG.

FIG. 3 is a schematic sectional view of a fixing device provided in the image forming apparatus of FIG.

FIG. 4 is a cross-sectional view illustrating a schematic configuration of a fixed image gloss detection unit according to the first embodiment of the present invention.

FIG. 5 is a flowchart illustrating an operation of detecting glossiness of a fixed image according to the first embodiment of the present invention.

FIG. 6 is a flowchart illustrating an operation of detecting glossiness of a fixed image according to the second embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a schematic configuration of a document image gloss detection unit according to a third embodiment of the present invention.

FIG. 8 is a flowchart illustrating an operation of detecting glossiness of a fixed image and a document image according to a third embodiment of the present invention.

FIG. 9 is a schematic sectional view of a fixing device provided in a conventional image forming apparatus.

[Explanation of symbols]

5 Fixing Device 16 Glossiness Detecting Means (Fixed Image Glossy Sensing Means) 51 Fixing Roller (Fixing Body) 52 Pressure Roller (Pressing Body) 101 Document 108 to 110 Glossiness Detecting Means (Original Image Glossy Sensing Means) P Recording Material

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Mitsuhiro Ota 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H033 AA10 AA11 BB04 CA01 CA26 CA30 CA36 CA39 CA40

Claims (8)

[Claims] An unfixed image is provided by heating and pressing a recording material carrying an unfixed image while nipping and transporting the recording material between the fixing member and the pressure member. Is fixed on the recording material to form a fixed image, the fixed image gloss detecting means for detecting the glossiness of the surface of the fixed image on the fixed recording material, and the fixed image gloss detecting means. A fixing unit configured to change a fixing processing condition so that the glossiness becomes a predetermined glossiness. 2. A fixing device comprising a fixing member and a pressurizing member which rotate in pressure contact with each other, wherein a recording material carrying an unfixed image formed in accordance with an original image is heated and heated while being nipped and conveyed by the fixing member and the pressurizing member. In a fixing device in which the unfixed image is fixed to the recording material by applying pressure to form a fixed image,
A fixed image gloss detecting means for detecting the gloss of the surface of the fixed image on the recording material after fixing, a document image gloss detecting means for detecting the gloss of the document image, and a gloss detected by the gloss detecting means. A fixing unit configured to change a fixing processing condition so that a difference between the glossiness detected by the document image gloss detection unit and the glossiness becomes a predetermined glossiness. 3. The fixed image gloss detecting means or the original image gloss detecting means is configured to detect a ratio of specular reflection light to total reflection light from the fixed image or the original image as glossiness. 2. The fixing device according to claim 1. 4. The apparatus according to claim 1, wherein the control unit changes the fixing processing condition so that the glossiness detected by the gloss detection unit becomes a predetermined glossiness during the continuous fixing process. 4. The fixing device according to claim 1. 5. The fixing device according to claim 1, wherein the control unit is capable of changing a fixing speed as a fixing processing condition. 6. The fixing device according to claim 1, wherein the control unit is capable of changing a fixing temperature as a fixing processing condition. 7. The fixing device according to claim 1, wherein the control unit is capable of changing a pressing force by the fixing body and the pressing body as a fixing processing condition. 8. An image forming apparatus for recording an image formed by a series of image forming processes on a recording material, comprising the fixing device according to claim 1. Description: Image forming apparatus.