JP3841265B2 - Fixing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fixing device that heats and presses a sheet holding an unfixed toner image with a heating roller and a pressure roller, and fixes the unfixed toner image onto the sheet. The present invention relates to a fixing device that can replace and use more than one type of heating roller.
[0002]
[Prior art]
In a fixing device of an electrophotographic printing apparatus, a toner image formed (electrostatic transfer) on a sheet is heated and pressed by a heating roller and a pressure roller to be fixed on the sheet, but a part of the toner image is heated. In general, a release agent is applied to the heating roller in order to prevent it from adhering to the roller surface and being re-fixed after the next page to cause erroneous printing.
[0003]
There are mainly two types of heating rollers, so-called hard rollers using a fluororesin or PFA tube, and so-called soft rollers using silicon rubber.
[0004]
In order to secure fixing strength when printing on thick paper such as postcards, it is necessary to set the surface temperature of the heating roller to a high temperature of about 190 ° C. to 200 ° C. Considering the wear resistance and thermal durability of the surface material, Use. On the other hand, when realizing high image quality by using approximately 90 kg of continuous paper, a soft roller is used to follow the irregularities of the paper without crushing the toner image. Therefore, it is necessary to set the surface temperature of the heating roller to a low temperature of about 160 ° C to 170 ° C.
[0005]
FIG. 3 shows an example of the difference in surface set temperature between the hard roller and the soft roller. Thereby, the release agent application mechanism to the heating roller is also roughly divided into two types. A conventional release agent coating mechanism for a heating roller in an electrophotographic printing apparatus will be described with reference to the drawings.
[0006]
4 and 5 are cross-sectional views showing a release agent coating mechanism for the heating roller according to the surface coating material of the heating roller. FIG. 4 shows a release agent coating mechanism when a hard roller is used. In the figure, 1 is a heating roller, and 2 is a pressure roller, and the toner image 4 is fixed on the printing paper 3 by electrostatic transfer. Here, the heating roller 1 includes a cored bar 1a, a surface coating material layer 1b provided on the cored bar 1a, and a heater 1c provided in the cored bar 1a.
[0007]
The release agent 5 is supplied from the tank 6 by the pump 7 to the release agent discharge unit 8 having a large number of holes 13 and is discharged from the holes 13. At this time, the discharged release agent 5 is uniformly applied to the heating roller 1 through the Euler belt 9 including the nonwoven fabric 10, the core 11, and the core 12 as an intermediate medium. The nonwoven fabric 10 of the Euler belt 9 is wound around a core A11 in a roller shape around a driven shaft (not shown), and the heating roller 1 and the nonwoven fabric 10 are printed during printing by a core B12 attached to a driving shaft (not shown). The nonwoven fabric 10 is wound up for each printing amount while slightly shifting the contact portion.
[0008]
FIG. 5 shows a release agent application mechanism when a soft roller is used. In this case, since the surface coating material 1b of the heating roller 1 is made of silicon rubber, which is difficult to wear, the Euler belt is difficult, and the oil roller 14 is used instead. The oil roller 14 has a cylindrical core material 14a and a nonwoven fabric 14b provided on the cylindrical core material 14a. The oil roller 14 is attached so as to be rotatable by an arm 15. The arm 15 is rotated by a spring 16 and is pressed against the heating roller 1 to be rotated.
[0009]
The release agent 5 is supplied from the tank 6 by the pump 7 to the release agent discharge unit 8 having a large number of holes 13 and is discharged from the holes 13. At this time, the discharged release agent 5 is uniformly applied to the heating roller 1 through the oil roller 14 as an intermediate medium.
[0010]
An example of the release agent application amount with respect to the print amount in each release agent application mechanism is shown in FIG.
[0011]
In the combination of the hard roller and the Euler belt, since the nonwoven fabric 10 is wound up, the release agent 5 soaked into the nonwoven fabric 10 is not applied to the heating roller 1 again, so that the application efficiency is poor, and the release agent. The application amount increases. On the other hand, in the combination of the soft roller and the oil roller, since the application efficiency is good because consideration is given to the swelling of silicon rubber and the nonwoven fabric 14 always follows the heating roller 1, the amount of release agent applied is reduced.
[0012]
[Problems to be solved by the invention]
In the above-described conventional fixing device, the surface coating material of the heating roller is distinguished and used according to the printing specifications, and the surface setting temperature of the heating roller and the amount of release agent applied are different. The surface set temperature of the heating roller and the amount of release agent applied are only one predetermined. When using a release agent coating mechanism that does not match the printing specifications, for example, when using a release agent coating mechanism that uses an Euler belt as a soft roller for high-quality printing, the life expectancy due to wear of the surface coating material of the heating roller is reduced. Will cause. Furthermore, the amount of the release agent applied to the heating roller will be insufficient, and an appropriate release property on the heating roller surface coating material layer cannot be ensured, resulting in an offset that causes the toner image to adhere to the heating roller. Causes the problem of poor printing.
[0013]
Conversely, when a release agent application mechanism using an oil roller is used as a hard roller for high-speed printing, an excessive amount of release agent is applied to the heating roller, resulting in a gloss difference in the solid black print image. The resulting vertical streak occurs. Furthermore, the problem of an increase in running cost of the release agent that is a consumable item will also be caused.
[0014]
In addition, if the surface temperature setting of the heating roller is not appropriate, it will not be possible to supply an appropriate amount of heat for fixing the toner image. This may cause problems such as poor fixing due to partial heat loss and uneven printing quality such as text blur due to excessive heat amount. become.
[0015]
As described above, when the printing specifications such as the importance of image quality and the corresponding amount of printing paper are different, it is difficult to share the release agent coating mechanism in the fixing device, and it is impossible to make a single housing in terms of the device configuration.
[0016]
The object of the present invention is to meet all printing specifications in one housing, and to share the soft roller and the hard roller only by exchanging the heating roller and oil roller which are consumables without changing the fixing device, In addition, the running cost of the release agent is not increased.
[0017]
[Means for Solving the Problems]
An object of the present invention is a fixing device that heats and presses a sheet holding an unfixed toner image with a heating roller and a pressure roller, and fixes the unfixed toner image on the sheet. In the fixing device that can be used by replacing the heating roller, a control unit that changes the surface set temperature of the heating roller and the amount of the release agent applied based on information on the mounted heating roller is provided. Achieved.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIG. Since the fixing process of the present invention is the same as that described in the prior art, it is omitted here. Further, the oil roller 14 and the release agent applying process to the heating roller 1 using the oil roller 14 are the same as those described with reference to FIG.
[0019]
Here, a control function for controlling the surface setting temperature of the heating roller and the amount of release agent applied according to the surface coating material 1b of the heating roller 1 according to the present invention will be described.
[0020]
In FIG. 1, the control unit 17 serves to control the lighting time and lighting cycle of the heater 1 c and the driving time and driving cycle of the pump 7. In addition, the controller 17 previously supplies the controller 1 with a lighting time and a lighting cycle of the heater 1c for realizing a set surface temperature of the heating roller 1 capable of supplying a heat amount necessary for fixing the toner image 4, and the releasing agent. Several driving times and driving cycles of the pump 7 determined in consideration of the amount of application 5 to the heating roller 1 are prepared.
[0021]
When the printing apparatus is used, the lighting control pattern of the heater 1c and the drive control pattern of the pump 7 according to the printing specifications such as the type of the surface coating material layer 1b of the heating roller 1 depending on the importance of image quality and the corresponding paper continuous amount. Select one from each. At this time, the lighting control pattern of the heater 1c and the control pattern of the pump 7 may be selected by any method such as manual automatic.
[0022]
Accordingly, an appropriate surface temperature setting corresponding to the heating roller 1 and the application of the release agent 5 are performed without changing the fixing device, and an appropriate fixing strength of the toner image and the heating roller 1 are set. The releasability with the surface coating material 1b can be secured.
[0023]
FIG. 2 shows an example of the release agent application amount with respect to the print amount in each release agent application mechanism.
[0024]
The reason why the amount of release agent applied in the combination of the hard roller and the oil roller of the present invention is smaller than the combination of the hard roller and the Euler belt of the prior art is that the application efficiency of the oil roller is good. to cause.
[0025]
Therefore, in the fixing device in the printing apparatus of one housing, the soft roller and the hard roller can be shared only by exchanging the heating roller and the oil roller, which are consumables, and the release agent running Cost can be reduced.
[0026]
【The invention's effect】
According to the present invention, even if the printing specifications such as the image quality importance and the corresponding paper continuous quantity are different, the printing apparatus is used as a single casing and the release agent application mechanism unit is shared, and the surface is changed according to the type of the heating roller. Since the controller controls the temperature and the amount of release agent applied, the hard roller and soft roller can be shared, and the running cost of the release agent that is a consumable item Can be suppressed.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an embodiment of a release agent application mechanism unit according to the present invention.
FIG. 2 is an explanatory diagram showing an example of a release agent coating amount with respect to a printing amount according to the present invention.
FIG. 3 is an explanatory diagram showing an example of a difference in surface set temperature between a hard roller and a soft roller.
FIG. 4 is a schematic view showing an embodiment of a release agent application mechanism unit according to the prior art.
FIG. 5 is a schematic view showing an embodiment of a release agent application mechanism unit according to the prior art.
FIG. 6 is an explanatory diagram illustrating an example of a release agent coating amount with respect to a printing amount according to a conventional technique.
[Explanation of symbols]
1 is a heating roller, 2 is a pressure roller, 3 is paper, 4 is a toner image, 5 is a release agent, 6 is a tank, 7 is a pump, 8 is a release agent discharge unit, 9 is an oil belt, and 10 is a non-woven fabric. , 14 is an oil roller.

Claims (2)

A fixing device that heats and presses a sheet holding an unfixed toner image with a heating roller and a pressure roller and fixes the unfixed toner image on the sheet, and replaces at least two different types of heating rollers. The fixing device can be used as a fixing device, and includes a control means for changing the surface setting temperature of the heating roller and the amount of the release agent applied based on information about the mounted heating roller. apparatus. The fixing device according to claim 1, wherein the information about the heating roller includes information about a surface coating material of the heating roller.

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