Patent Publication Number: US-10310423-B2

Title: Heating roller having three heaters of three different heating sections and image forming apparatus using such heating roller

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of No. 106122786 filed in Taiwan R.O.C. on Jul. 7, 2017 under 35 USC 119, the entire content of which is hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This disclosure relates to a heating roller and an image forming apparatus using the same, and more particularly to a heating roller having three heaters of three different heating sections and an image forming apparatus using the same. 
     Description of the Related Art 
     A conventional heating roller only has a single heater, and a length of the heater is approximately equal to an axial length of the heating roller. When the maximum copy area of the copier is designed to be equal to the A3 size, the heater over the entire axial length of the heating roller needs to be used. If the original has the A4 size, then only the heater in the axial middle portion of the heating roller is used to fix the A4 size sheet. This wastes the heat generated in the axial areas on two sides of the heating roller, thereby wasting electrical energy or easily consuming the heating roller. In addition, because the heat in the axial areas on two sides of the heating roller is not taken away by sheets, the temperature thereon easily gets too high, so that the thermometer inside the heating roller senses the high temperature to turn off the power, and the copier enters a pause state. 
     Therefore, how to provide a heating roller capable of avoiding the energy waste and too-high temperature is a problem to be solved by this disclosure. 
     BRIEF SUMMARY OF THE INVENTION 
     An objective of this disclosure is to provide a heating roller and an image forming apparatus using the same to avoid the energy waste and too-high temperature, wherein the heating roller is applicable to various sizes of print sheets. 
     To achieve the above-identified object, this disclosure provides a heating roller including: a roller cylinder rotatably disposed; a base rotatably disposed in the roller cylinder; first to third heaters, which are mounted on the base, and respectively have a first heating section, a second heating section and a third heating section extending in directions substantially parallel to an axial direction of the roller cylinder; and a driving mechanism, which is connected to the base and rotates the base to multiple position states. The first to third heating conditions different from one another are provided according to the position states in conjunction with power-on and power-off states of the first heating section, the second heating section and the third heating section. 
     In the above-mentioned aspect, the roller cylinder provides the first to third heating conditions to cooperate with a pressure roller to fix toner onto first to third sheets having different widths. 
     This disclosure further provides an image forming apparatus including: the above-mentioned heating roller and pressure roller; and a control processor, which receives a printing signal so that the toner is fixed onto one of the first to third sheets. The control processor controls the driving mechanism to rotate the base to the position states according to width information of the printing signal. 
     This disclosure further provides an image forming apparatus including: the above-mentioned heating roller and pressure roller; a width detector, which detects a width of one of the first to third sheets to obtain a width signal; and a control processor, which receives a printing signal and the width signal so that the toner is fixed onto one of the first to third sheets. The control processor controls the driving mechanism to rotate the base to the position states according to width information of the width signal. 
     With the above-mentioned heating roller and image forming apparatus using the same, the print or copy procedures of more than three different sizes of sheets can be easily implemented, too-high temperature of the heating roller can be effectively avoided, the stable operational effect can be achieved, the waste of the heating power can be further effectively avoided, and the energy saving requirements of environmental protection can be achieved. 
     Further scope of the applicability of this disclosure will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of this disclosure, are given by way of illustration only, since various changes and modifications within the spirit and scope of this disclosure will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a schematic side view showing an image forming apparatus according to a first embodiment of this disclosure. 
         FIG. 2  is a schematic side view showing a heating roller and a pressure roller of  FIG. 1  in a first position state. 
         FIG. 3  is a schematic side view showing the heating roller and the pressure roller of  FIG. 1  in a second position state. 
         FIG. 4  is a schematic view showing sheets with different widths and the width direction of the heating roller of  FIG. 1 . 
         FIG. 5  is a schematic view showing sheets having different widths and the width direction of the heating roller according to a second embodiment of this disclosure. 
         FIG. 6  is a schematic view showing sheets having different widths and the width direction of the heating roller according to a third embodiment of this disclosure. 
         FIG. 7  is a schematic side view showing the heating roller and the pressure roller in the second position state according to the third embodiment of this disclosure. 
         FIG. 8  is a schematic side view showing the heating roller and the pressure roller in the third position state according to the third embodiment of this disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a schematic side view showing an image forming apparatus  100  according to a first embodiment of this disclosure. As shown in  FIG. 1 , the image forming apparatus  100 , such as a printer, a copier or a multi-function peripheral, includes a printing module  10 , a transporting mechanism  20  and a discharge mechanism  30 . 
     The printing module  10  sequentially prints data on multiple sheets M (it is represented by first to third sheets M 1  to M 3  in  FIG. 4 ). The transporting mechanism  20  transports the sheets M past the printing module  10 . In this embodiment, the transporting mechanism  20  includes transporting rollers  21 ,  22 ,  23  and  24 . In this embodiment, the laser printing module used in a laser printer is taken as an example for illustration, but this disclosure is not restricted thereto. 
     In the printing module  10 , a toner cartridge  11  accommodates toner C, and a supply roller  17  is rotatably disposed on the toner cartridge  11  to supply the toner C to a rotatable development roller  16 . A charger  13  uniformly charges a rotatable drum  15 , and a laser scanning unit  12  outputs a laser beam to form an electrostatic pattern on the drum  15 . A transfer roller  14  and the drum  15  are rotatably disposed upstream of a heating roller  19  (the effect of the fixation is provided in this embodiment, so it is also known as the fixation roller), and nip the sheet M fed from the rollers  23  and  24  therebetween to transfer the electrostatic pattern of the drum  15  onto the sheet M. Then, the sheet M is processed by a pressure roller  18  and the heating roller  19  so that the toner C is fixed onto the sheet M. Then, the fixed sheet M enters a sheet passage P. The discharge mechanism  30  includes a first roller  34  and a second roller  37 , which are located downstream of the transporting mechanism  20 , and transport the sheets M to a discharge tray. 
       FIGS. 2 and 3  respectively show the heating roller and the pressure roller of  FIG. 1  in two position states.  FIG. 4  is a schematic view showing a width direction of the heating roller. As shown in  FIGS. 1 to 4 , the heating roller  19  includes a roller cylinder  191 , a base  192 , first to third heaters  193 ,  194  and  195  and a driving mechanism  199 . 
     The roller cylinder  191  is rotatably disposed on, for example, a body or a housing of the image forming apparatus  100 . It is worth noting that the roller cylinder can also be implemented by a belt in conjunction with a heat-collecting metal sheet or a reflective sheet to provide the heat source for the roller cylinder. The base  192  may be rotatably disposed in the roller cylinder  191  and is rotatable relative to the roller cylinder  191 . For example, the base  192  may be in the form of a cylindrical frame. The first to third heaters  193 ,  194  and  195  are, for example, heating lamps mounted on the base  192 , and respectively have a first heating section  196 , a second heating section  197  and a third heating section  198  (including two heating sub-sections) extending in directions substantially parallel (may have a skew angle ranging from 0 to 2, 3, 4 or 5 degrees) to an axial direction of the roller cylinder  191  (perpendicular to the paper direction of  FIGS. 2 and 3 ), and the axial direction of the roller cylinder  191  is the horizontal direction of  FIG. 4 . In the first embodiment, when being axially or orthographically projected on the central axis of the roller cylinder  191 , a second range R 2  of the second heating section  197  covers and is larger than a first range R 1  of the first heating section  196 , the second range R 2  ranges between two third ranges R 3  of the third heating section  198 , and the second range R 2  is complementary to the two third ranges R 3 . In this embodiment, the two third ranges R 3  are located on two sides of the second range R 2 . The driving mechanism  199  is composed of a motor and a gear set, for example. In this embodiment, the driving mechanism  199  is connected to the base  192  and rotates the base  192  to multiple position states, such as a first position state ( FIG. 2 ) and a second position state ( FIG. 3 ). The first to third heating conditions different from one another are provided according to the position states in conjunction with power-on and power-off states of the first heating section  196 , the second heating section  197  and the third heating section  198 . The first to third heaters  193 ,  194  and  195  have the same axial length, and this facilitates the power supply to the first to third heaters  193 ,  194  and  195 . It is worth noting that in another example, the first to third ranges R 1  to R 3  may overlap slightly to avoid heat loss at the edges of heating sections. The first to third heating sections may be implemented by using resistor silks having high resistance or filaments. The sections other than the first to third heating sections are non-heating sections and have no effect of heating, but have an electroconductive effect and may be implemented by using the wires with the low resistance. For example, the third heater may be achieved by using a length of wire serially connected between two sections of the resistor silks or the filaments. 
     In this embodiment, the roller cylinder  191  provides the first to third heating conditions to cooperate with the pressure roller  18  to respectively fix the toner C onto the first to third sheets M 1  to M 3  having different widths. Thus, the first to third heating conditions relate to the widths of heating. For example, the first to third sheets M 1  to M 3  respectively have A5, A4 and A3 dimensions. 
     As shown in  FIG. 2 , in the first position state, the first heating section  196  is powered on to make the roller cylinder  191  provide the first heating condition, and the first heater  193  is closer to the pressure roller  18  than the second and third heaters  194  and  195 , so that heating efficiency can be improved, and the waste of the heat source can be reduced. The length of the heating section of the first heater  193  is short, is suitable for printing sheets having smaller sizes, such as sheets having A5 sizes or smaller sizes, and the required electrical energy is low. 
     As shown in  FIG. 3 , in the second position state, the first heater  193  is further from the pressure roller  18  than the second and third heaters  194  and  195 , and the second heating section  197  is powered on to make the roller cylinder  191  provide the second heating condition. The length of the heating section of the second heater  194  is moderate, and is suitable for printing sheets having medium sizes, such as the A4-sized sheets or sheets having the widths ranging between A4 and A5 sizes, and the required electrical energy is moderate. Also, in the second position state, the second heating section  197  and the third heating section  198  are powered on to make the roller cylinder  191  provide the third heating condition, and sheets having A3 sizes can be printed in the heating condition. In addition, in the second position state, a distance between the second heater  194  and the pressure roller  18  is equal to a distance between the third heater  195  and the pressure roller  18 , that is, the connection line between the second heater  194  and the third heater  195  with respect to the center point of the pressure roller  18  and the heating roller  19  is symmetrical. 
     Thus, the image forming apparatus  100  provided by this embodiment includes the above-mentioned heating roller  19  and pressure roller  18  and a control processor  40  (see  FIG. 1 ). The control processor  40  receives a printing signal PS so that the toner C is fixed onto one of the first to third sheets M 1  to M 3 , and the control processor  40  controls the driving mechanism  199  to rotate the base  192  to the position states (the first position state and the second position state in this embodiment) according to width information of the printing signal PS. 
     In another implementation method, the image forming apparatus  100  includes the heating roller  19 , the pressure roller  18 , a width detector  50  and the control processor  40 . The width detector  50  detects a width of one of the first to third sheets M 1  to M 3  to obtain a width signal WS. The control processor  40  receives width information of the printing signal PS and the width signal WS, so that the toner C is fixed onto one of the first to third sheets M 1  to M 3 . The control processor  40  controls the driving mechanism  199  to rotate the base  192  to the position states (the first position state and the second position state in this embodiment) according to the width information. When the control processor  40  receives information on the malfunction of the first heater  193 , the second heater  194  may be rotated to a position closest to the pressure roller  18 , and the second heater  194  is used to temporarily replace the heating function of the first heater  193 . 
       FIG. 5  is a schematic view showing sheets having different widths and the width direction of the heating roller according to the second embodiment of this disclosure. As shown in  FIG. 5 , in the axial direction, a first range R 1  of the first heating section  196  is located between two second ranges R 2  of the second heating section  197 , the two second ranges R 2  are respectively located between three third ranges R 3  of the third heating section  198 , and the two second ranges R 2  are complementary to the three third ranges R 3 . That is, the second and third ranges R 2  and R 3  do not overlap with each other but are complementary to one another. In addition, a middle one of the three third ranges R 3  is overlapped with the first range R 1  and has the same length as the first range R 1 . In this case, the two position states of  FIGS. 2 and 3  are also applicable. In the first position state, the first heating section  196  is powered on (or the first heater  193  is powered on) to make the roller cylinder  191  provide the first heating condition. In the second position state, the first heating section  196  and the two second heating sections  197  are powered on (or the first heater  193  and the second heater  194  are powered on) to make the roller cylinder  191  provide the second heating condition. In the second position state, the two second heating sections  197  and the three third heating sections  198  are powered on (or the second heater  194  and the third heater  195  are powered on) to make the roller cylinder  191  provide the third heating condition. When the control processor  40  receives information on the malfunction of the first heater  193 , the third heater  195  may be rotated to a position closest to the pressure roller  18 , and the third heater  195  is used to temporarily replace the heating function of the first heater  193 . 
       FIG. 6  is a schematic view showing sheets having different widths and a width direction of a heating roller according to a third embodiment of this disclosure.  FIGS. 7 and 8  are schematic side views showing the heating roller and the pressure roller in the second and third position states according to the third embodiment of this disclosure. As shown in  FIGS. 6 to 8 , in the axial direction, the third range R 3  of the third heating section  198  covers and is larger than the second range R 2  of the second heating section  197 , and the second range R 2  covers and is larger than the first range R 1  of the first heating section  196 . There are three types of position states in the third embodiment. In the first position state similar to the schematic side view of  FIG. 2 , the first heater  193  is closer to the pressure roller  18  than the second and third heaters  194  and  195 , and the first heating section  196  (or the first heater  193 ) is powered on to make the roller cylinder  191  provide the first heating condition. In the second position state, as shown in  FIG. 7 , the second heater  194  is closer to the pressure roller  18  than the first and third heaters  193  and  195 , and the second heating section  197  (or the second heater  194 ) is powered on to make the roller cylinder  191  provide the second heating condition. In the third position state, as shown in  FIG. 8 , the third heater  195  is closer to the pressure roller  18  than the first and second heaters  193  and  194 , and the third heating section  198  (or the third heater  195 ) is powered on to make the roller cylinder  191  provide the third heating condition. That is, the heating actions of the first to third heaters are independent, and because a distance between each powered heater and the pressure roller  18  may be adjusted to a minimum, the power consumption is lower. In addition, when the first heater  193  fails, the base  192  may be rotated to temporarily provide alternative heating functions using the second heater  194 . When the second heater  194  fails, the base  192  may be rotated to temporarily provide alternative heating functions using the third heater  195 . It is worth noting that the heating rollers of the first to third embodiments are also applicable to the above-mentioned image forming apparatus  100 , and the above-mentioned heating roller may also be applied to other occasions that require different heating conditions. 
     With the above-mentioned heating roller and image forming apparatus using the same, the print or copy procedures of more than three different sizes of sheets can be easily implemented, too-high temperature of the heating roller can be effectively avoided, the stable operational effect can be achieved, the waste of the heating power can be further effectively avoided, and the energy saving requirements of environmental protection can be achieved. 
     While this disclosure has been described by way of examples and in terms of preferred embodiments, it is to be understood that this disclosure is not limited thereto. To the contrary, it is intended to cover various modifications. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications.