JP4568153B2 - Fixing apparatus, image forming apparatus, and heating control method of fixing apparatus - Google Patents

Description

  The present invention relates to a fixing device used in an image forming apparatus, an image forming apparatus using the fixing device, and a heating control method for a heater for the fixing device.

  In the fixing device of the image forming apparatus, in order to shorten the start-up time of the apparatus, it is necessary to shorten the time required to reach the fixable temperature when the fixing device is heated. For this reason, the first and second heating sources (heating heaters) and heating sources (pressure heaters) for heating the first rotating body (heating roller) and the second rotating body (pressure roller) respectively are heaters. It is necessary to increase the heat capacity. However, it is difficult to simply increase the heat capacity of the heater because of the increase in maximum power consumption and compliance with flicker regulations. For this reason, a plurality of fixing heaters are divided into heaters having a small capacity and a plurality of light distributions.

  Such a fixing device having a plurality of heaters is disclosed in, for example, Patent Document 1 or 2. As related inventions, the inventions described in Patent Documents 3 to 7 are also known.

  Among these, Patent Document 1 discloses an endless fixing belt for conveying a sheet-like medium on which toner is fixed, a heating roller and a fixing roller around which the fixing belt is wound, and the fixing via the fixing belt. A pressure roller disposed opposite the roller, a first temperature detection means for detecting the temperature of the heating roller, a second temperature detection means for detecting the temperature of the fixing roller, and In a fixing device having control means for controlling the temperature of the heating roller to become a set temperature based on a detection signal of the first temperature detection means, the set temperature of the heating roller is detected by the second temperature detection means. There is a set temperature determining means that determines based on the signal, and the temperature control is accurately controlled by performing temperature control corresponding to the temperature drop due to rotation of the fixing belt so that the fixing is good. There, the fixing property is disclosed an invention that aims to provide a fixing device of stabilized belt type.

Further, Patent Document 2 discloses a fixing roller positioned on the side facing a visible image on a transfer material formed based on a light image of the image obtained by illuminating an original image with an exposure unit, and the fixing roller. In the fixing device for fixing the visible image on the transfer material by passing the transfer material between the pressure roller and the pressure roller, a temperature sensor and a heater with different power consumption are disposed on each of the fixing roller and the pressure roller. These are controlled independently of each other, and the control temperature of the pressure roller, which is set lower than the set temperature of the heating roller, is higher during paper feeding than during standby, and the pressure roller temperature during paper feeding is higher. It is configured so that the heaters of the fixing roller and pressure roller are not turned on simultaneously when the temperature of the heating roller approaches and the exposure unit is in operation, and the temperature is controlled within a range where power consumption can be satisfied. So, a fixing device is disclosed in which to be able to fit into the standard power supply capacity and prescribed power consumption advance to prevent the fixing property with a decrease in temperature of the pressure roller.
JP 2003-156966 A Japanese Patent No. 3186906 Japanese Patent Laid-Open No. 09-016015 Japanese Patent Laid-Open No. 11-161095 JP 2001-056622 A JP 2003-307963 A JP 2004-045687 A

  However, in the fixing device having a plurality of heaters as described above, if all of the plurality of heaters are turned on at the same time, this is the same as an increase in the heat capacity of the heater. It becomes difficult to comply with regulations.

  The present invention has been made in view of such a background, and an object thereof is to suppress the maximum power consumption by simple control and satisfy the flicker regulation.

To achieve the above object, the invention according to claim 1, by passing the recording medium between the first rotating member and second rotating member, the fixing device for fixing an image on the recording medium , a pair of the heating source for heating the first rotating body, a first temperature detecting means for detecting the surface temperature of the first rotary member, and a pressure heat source you heat the second rotor pressurizing second temperature sensing means, the pair of the heating source and the pressurized heat source based on the first temperature detecting means and the temperature sensed by the second temperature detecting means for detecting the surface temperature of the second rotary member each control means for controlling includes a control unit the heating amount of the, at the time of fixing standby, pressurized hot source is turned one heating source in this order of the pair of the heating source off one heat source of the performing control to turn the other heat source of the pair of the heating source at the time of the in And features.

According to another aspect of the present invention, there is provided a fixing device for fixing an image on the recording medium by passing the recording medium between the first rotating body and the second rotating body. A pair of heating sources for heating the first rotating body, first temperature detecting means for detecting the surface temperature of the first rotating body, and a pressurized heat source for pressurizing and heating the second rotating body; A pair of heating source and pressure heat source based on the temperature detected by the second temperature detecting means for detecting the surface temperature of the second rotating body, the first temperature detecting means and the second temperature detecting means Control means for controlling the heating amount of each of the pair of heating sources, and when the recording medium passes, the control means turns on one heating source of the pair of heating sources and the other heating source in this order, Turn on the pressurized heat source when both the source and the other heating source are turned off. And performing control.

According to a third aspect of the present invention, in the fixing device according to the second aspect, the control unit performs a control to turn off the pressure heat source when the temperature of the recording medium is increased before passing .

According to a fourth aspect of the present invention, in the fixing device according to any one of the first to third aspects, one of the pair of heating sources is a central heater having a light distribution characteristic in the central portion. One is an end heater having a light distribution characteristic at the end .

According to a fifth aspect of the present invention, in the fixing device according to any one of the first to fourth aspects, the pair of heat sources are provided in a first rotating body that rotates around a fixing belt. And

According to a sixth aspect of the present invention, in the fixing device according to any one of the first to fifth aspects, the first rotating body heats the image forming surface to be fixed on the recording medium. .

According to a seventh aspect of the present invention, in the fixing device according to any one of the first to sixth aspects, the second rotating body is located on the non-image forming surface of the recording medium or the image forming surface that is not a fixing target. The pressurizing heat source that is in contact with the recording medium pressurizes and heats the non-image forming surface side of the recording medium or the image forming surface side that is not a fixing target .

According to an eighth aspect of the present invention, in the fixing device according to any one of the first to seventh aspects, a heating member that is heated by a pair of heating sources and contacts the fixing target side, and a pressure member that pressurizes the recording medium The heat capacity is set such that the heat capacity of the heating member <the heat capacity of the pressure member .

According to a ninth aspect of the present invention, an image forming apparatus includes the fixing device according to any one of the first to eighth aspects .

Furthermore, in order to achieve the object, the invention described in claim 10 is a fixing device for fixing an image on the recording medium by passing the recording medium between the first rotating body and the second rotating body. In this heating control method, one of the pressure heat source that pressurizes and heats the second rotator and the pair of heat sources that heat the first rotator during standby for fixing the recording medium is turned on in this order. The control is performed to turn on the other heating source of the pair of heating sources when the one heating source is turned off.

In addition, in order to achieve the object, the invention described in claim 11 is a fixing for fixing an image on the recording medium by passing the recording medium between the first rotating body and the second rotating body. In the heating control method of the apparatus, one heating source and the other heating source of the pair of heating sources that heat the first rotating body when the recording medium passes are turned on in this order, and the one heating source and the other heating source are turned on in this order. Control is performed to turn on a pressurized heat source that pressurizes and heats the second rotating body when both of the heating sources are turned off .

According to a twelfth aspect of the present invention, in the heating control method for a fixing device according to the eleventh aspect, control is performed to turn off the pressure heat source when the temperature of the recording medium is increased before passing .

In the following embodiments, the first rotating body fixing roller, a heating roller and the fixing belt, the pair of pressing a heat source to the heater 321, 322, the first temperature sensing means first temperature sensor 350 In addition, the second rotating body is the pressure roller 340, the pressure heat source is the pressure heater 341, the second temperature detection means is the second temperature detection sensor 351, the control means is the control unit 701, and so on. Each corresponds.

According to the present invention, at the time of fixing standby or passage of the recording medium is controlled so that a plurality of heat sources are not turned on at the same time, also at Atsushi Nobori before passage of the recording medium, the on-off state of the pressurizing heat source Regardless, since the pressurized heat source is turned off, the maximum power consumption can be suppressed and the flicker regulation can be satisfied.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
FIG. 1 is a diagram showing a schematic configuration of a color printer as a color image forming apparatus according to an embodiment of the present invention. In FIG. 1, the color printer basically includes an image forming unit 100, a paper feed unit 200, a fixing unit 300, and a paper discharge unit 400.

  The image forming unit 100 includes CMYK photosensitive drums 101C, 101M, 101Y, and 101K, a writing unit for each color (not shown) that performs optical writing on the photosensitive drums 101C, 101M, 101Y, and 101K, and a photosensitive drum. Contact with the body drums 101C, 101M, 101Y, and 101K, and face each of the photosensitive drums 101C, 101M, 101Y, and 101K with the transfer belt 102 sandwiched between the drive pulley and the driven pulley. The transfer roller 103C, 103M, 103Y, 103K provided at the position where the transfer is performed, and the transfer roller 104 provided downstream of the black transfer portion and sandwiching the vertical conveyance path 105 are mainly configured.

  The sheet feeding unit 200 conveys the first and second sheet feeding trays 210 and 220 and the transfer sheets 212 and 222 fed from the sheet feeding trays 210 and 220 by the sheet feeding rollers 211 and 221 to the longitudinal conveyance path 105. A transfer sheet conveyance path 106 for manual transfer, and a manual feed tray 230 for manually feeding the transfer sheet to the vertical conveyance path 105.

  The fixing device 300 is provided on the downstream side of the longitudinal conveyance path 105 in the transfer sheet conveyance direction, and includes a fixing roller 310, a heating roller 320, a fixing belt 330, and a pressure roller 340.

  The paper discharge unit 400 is provided on the downstream side of the fixing device 300 in the transfer paper conveyance direction, and includes a paper discharge roller 410 and a paper discharge tray 420.

  In the color printer configured as described above, the transfer paper fed from the paper feed trays 210 and 220 or the manual feed tray 230 is sent out to the vertical conveyance path 105 and is formed by the image forming unit 100 that performs development and transfer. The full-color image superimposed on the surface of the transfer belt 102 is transferred onto the transfer paper by the transfer roller 104. The unfixed image transferred onto the transfer paper is sent to the fixing device 300 and is formed by a fixing roller 310 and a pressure roller 340 that are driven and driven inside the fixing belt 330 whose surface is heated by a heat source such as a heater. As a result, the sheet is fixed on the surface of the transfer paper and becomes a semi-permanent image, and is discharged to the discharge tray 420.

  FIG. 2 is a diagram illustrating a detailed configuration of the fixing device 300. The fixing device 300 includes a fixing roller 310, a heating roller 320, and a fixing belt 330 stretched between them. The fixing roller 310 and the heating roller 320 are fixed and are fixed by a spring (pressing means or elastic biasing means) not shown. Appropriate tension is held by a belt tension member (tension roller) 331 under pressure. In addition, an appropriate pressure is applied between the fixing roller 310 and the pressure roller 320 which are located on the inner side of the fixing belt 330 and formed of an elastic body, and thereby, a nip is formed between the fixing belt 330 and the pressure roller 340. Is formed.

  First and second heaters 321 and 322 are provided inside the heating roller 320, and the heating roller 320 is heated from the inside by the heaters 321 and 322 to heat the fixing belt 330. In this embodiment, there are two heaters, but more heaters may be used. Also, a temperature detection sensor 350 is provided on the outer peripheral portion of the heating roller 320 to detect the surface temperature of the fixing belt 330 in contact or non-contact, and the first heater is based on the detected surface temperature of the fixing belt 330. The energization of 321 is controlled to control the surface temperature of the fixing belt 330 to an appropriate temperature range. A heating heater (hereinafter referred to as a pressure heater) 341 is also provided inside the pressure roller 340, and the surface temperature of the pressure roller 340 is detected by a temperature detection sensor 351 provided on the outer periphery of the pressure roller 340. Then, the energization of the pressure heater 341 is controlled based on the detected surface temperature of the pressure roller 340, and the surface temperature of the pressure roller 340 is controlled within an appropriate temperature range. A cleaning member 360 is provided on the outer peripheral portion of the pressure roller 340 so as to clean dirt adhering to the surface of the pressure roller 340.

  In this embodiment, the fixing-side rotating body (fixing belt 330) side is the image surface side of the transfer paper P, and the pressure-side rotating body (pressure roller 340) side is the non-image side, and an unfixed image formed on the transfer paper 212 610 is fixed to the transfer paper 212 while passing through the nip heated as described above. That is, the fixing toner image 620 adheres to the surface of the transfer paper 212 and is fixed.

  Reference numeral 371 denotes an inlet guide plate, 372 denotes a separating member, and 373 denotes an outlet guide plate. In this embodiment, the heat capacity of the heating side member including the fixing belt 330, the fixing roller 310, and the heating roller 320 is set to be smaller than the heat capacity of the pressure roller 340. By configuring in this way, it is not necessary to use a plurality of pressure heaters 341 like the first and second heaters 321 and 322.

  FIG. 3 is a block diagram showing the configuration of the control circuit of the image forming apparatus according to the present embodiment, and only the part related to the control of the fixing device is shown. The control circuit 700 includes a control unit (CPU) 701 including a ROM and a RAM (not shown), a first temperature detection sensor 350 that detects the surface temperature of the fixing belt 330, and a second temperature that detects the surface temperature of the pressure roller 340. A temperature detection sensor 351; first and second heating heaters 321 and 322; a pressure heater 341; a fixing roller 310; and a driving motor 365 that rotationally drives the pressure roller 340. The sensors 350 and 351, each heater 321, 322, and 341 and a drive motor 365 are connected to the control unit 701. The control unit 701 executes a predetermined process programmed using a RAM (not shown) as a work area according to a program stored in a ROM (not shown).

  FIG. 4 is a flowchart showing a control procedure executed by the control unit 701. In the control procedure of FIG. 4, first, it is checked whether or not the transfer paper has passed through the fixing device 300, that is, so-called paper passing (step S1), and if it is paper passing, the pressure roller 340 is heated. It is checked whether there is a pressure heater ON request (step S2). Although referred to as paper passing here, the recording medium may be other than transfer paper, for example, a film type such as an OHP sheet. In this case, the recording medium corresponds to the state of passing through the nip. . If there is no heater turn-on request in step S2, the process returns to step S1, and if there is a turn-on request, it is checked whether there is a turn-on request for the first and second heat rollers of the heat roller 320 (step S3). If there is a request to turn on the first and second heaters 321 and 322, the process returns to step S2, and if there is no request to turn on, the turning on of the first and second heaters 321 and 322 is prohibited (step S4). Then, the pressure heater 341 is turned on (step S5), and the energization state of the pressure heater 341 controlled based on the temperature monitoring of the second temperature detection sensor 351 is turned off (step S6). The on prohibition of the first and second heaters 321 and 322 is canceled (step S7), and the process returns to step S1.

  When the paper is not passed in step S1 (standby) (step S1-N), it is checked whether or not the residual heat fixing is performed (step S8), and if the residual heat fixing is not performed, Finish the process. On the other hand, if the residual heat fixing has been performed, it is checked whether or not the pressure heater 341 is turned on (step S9). If the pressure heater 341 is turned on, the first and second heaters 321 and 322 are simultaneously turned on. Turning on is prohibited (step S10), and the pressure heater 341 is turned on (step S11). Then, when the pressure heater 341 is turned off by the control based on the temperature monitoring (step S11), the prohibition state of the step S10 is canceled, that is, the first and second heaters 321 and 322 are prohibited from being simultaneously turned on. The state is released (step S12), and the process returns to step S1.

  By controlling in this way, desired heating control can be performed without the three of the first and second heaters 321 and 322 and the pressure heater 341 being simultaneously turned on.

  The control timing at this time is shown in the timing chart of FIG. FIG. 5A shows the on / off timing of the three heaters 321, 322, and 341 during standby in step S 1, not during paper passing. After the pressure heater 341 is turned on in step S 9, When the first heater 321 is turned on and the first heater 321 is turned off, the second heater 322 is turned on. This is because it is prohibited in step S10 that the first and second heaters 321 and 322 are simultaneously turned on. In this embodiment, the first heater 321 (shown as the heater 1 in FIGS. 4 and 5) is disposed at the center of the heating roller 320, and the second heater 322 (in FIGS. 4 and 5). Each heater is arranged so that the end of the heating roller 320 is heated. At this timing, the ON state of the pressure heater 341 and one of the first and second heaters 321 and 322 may overlap, but the ON state of the first and second heaters 321 and 322 overlap. There is no.

  FIG. 5B shows the on / off timing of the three heaters 321, 322, and 341 at the time of passing paper. When the pressure heater 341 is off (step S 2 -N), the first and second heaters 321, 322, and 341 are turned on and off. When the heaters 321 and 322 are turned on and both the first and second heaters 321 and 322 are turned off (step S4), the pressure heater 341 is turned on (step S5), and the pressure heater 341 is turned off. (Step S6), the second heater 322 is turned on (Step S7). At this timing, the ON state of the first and second heaters 321 and 322 may overlap, but the ON state of the pressure heater 341 and the first and second heaters 321 and 322 do not overlap.

  In the above embodiment, it is described that an image is formed on one side of the transfer paper 212 and the image is fixed. However, the same applies to the case where images are formed on both sides of each side. In this case, the image forming surface on the non-fixing side comes into contact with the pressure roller 340.

  As described above, according to the present embodiment, the following effects can be obtained.

  In other words, when the fixing unit 300 is on standby, the pressure heater 341 is on / off controlled regardless of whether the heaters 321 and 322 are on or off. Simple control independent of the state can be achieved.

  When the fixing unit 300 passes the paper, the pressure heater 341 is controlled to be on / off so that it does not overlap with the heaters 321 and 322 being turned on, so that the maximum power consumption can be reduced and flicker regulations can be met. It becomes.

  Since there are two or more heaters 321 and 322, and they are controlled so that they do not overlap each other during standby, the maximum power consumption can be reduced and flicker regulations can be accommodated.

  There are two or more heaters 321 and 322, and they are controlled so that they may overlap each other when the paper is passed. Therefore, the heating is reduced while reducing the maximum power consumption and complying with the flicker regulations. Control of the heaters 321 and 322 can be made simple control independent of the state of each other.

  Since at least one of the plurality of heaters 321 and 322 has a light distribution characteristic at the center, and at least one of the other heaters is divided into end heaters having a light distribution characteristic at the end, and the functions are divided. Maximum power consumption can be reduced and flicker regulations can be met.

  Since the heaters 321 and 322 are provided in the heating roller 320 that is rotated around the fixing belt 330, the structure of the heaters 321 and 322 can be simplified and the thermal efficiency can be improved.

  Since the pressure heater 341 that heats the pressure roller 340 heats the back side of the image on the transfer paper 212, the fixing structure can be effectively performed by thermal fixing.

  Since the heat capacity of the heating side member composed of the heating roller 320, the fixing belt 330, and the fixing roller 310 is smaller than that of the pressure side member, it is not necessary to use a plurality of pressure heaters 341.

<Second Embodiment>
In the first embodiment, control is performed so that the ON states of a plurality of heaters do not overlap according to conditions so as to reduce the maximum power consumption and respond to the flicker regulation. In this condition, the pressure heater is actively turned off to obtain the same effect as in the first embodiment.

  FIG. 6 is a flowchart showing the control procedure according to the second embodiment, and FIG. 7 is a timing chart showing the relationship of the heating timing of the heater in the second embodiment. Since the image forming apparatus, the fixing apparatus, and the control circuit itself are configured in the same manner as the first embodiment shown in FIGS.

  In the second embodiment, first, it is checked whether the fixing unit 300 is in a paper passing state or a pre-passage temperature rising state (step S21), and if it is a notification state or a pre-passage temperature rising state (step S21-Y). ), The pressure heater 341 is turned off and the state is maintained (step S22). In this state, one of the first and second heaters 321 and 322 can be turned on, or both can be turned on (step S23). Then, in this state, the end of the sheet passing is checked (step S24), and the process is terminated assuming that the fixing of the sheet being passed is completed when the notification is completed.

  On the other hand, if the fixing unit 300 is not in the sheet passing state or in the pre-passage temperature rising state (step S21-N), it is checked whether or not the remaining heat fixing is performed (step S25), and the remaining heat fixing is not performed. If so, the process is terminated. On the other hand, if the residual heat fixing has been performed, it is checked whether any of the heaters 321 and 322 is on (step S26). If not, the process returns to step S21 and the subsequent processing is repeated. The pressure heater 341 is prohibited from being turned on (step S27), and the first and second heaters 321 and 322 are turned on (step S28). For example, when the heating roller 320 is heated up to a predetermined temperature and both the first and second heaters 321 and 322 are turned off, the ON state of the pressure heater 341 is canceled (step S30), and the pressure heater After making the heating possible, the process returns to step S21 and the subsequent processing is repeated.

  By controlling in this way, desired heating control can be performed without the three of the first and second heaters 321 and 322 and the pressure heater 341 being simultaneously turned on.

  The control timing at this time is shown in the timing chart of FIG. FIG. 7A shows the on / off timing of the three heaters 321, 322, and 341 when paper is passed in step S 21. The pressure heater 341 is turned off in step S 22, and the first and / Alternatively, when the second heaters 321 and 322 are turned on, here, when the first heater 321 is turned on, the second heater 322 is turned on for a shorter period of time than the first heater 321 and both heating is performed. This shows that the heaters 321 and 322 are simultaneously on. However, the pressure heater 341 and the first and / or second heaters 321 and 322 are not turned on at the same time.

  FIG. 7B shows the on / off timing of the three heaters 321, 322, 341 during standby, and the pressure heater when any of the heaters 321, 322 is on (step S 26 -Y). When the pressure heater 341 is off, the first and / or second heaters 321 and 322 are turned on. At this timing, the ON state of the first and second heaters 321 and 322 may overlap, but the ON state of the pressure heater 341 and the first and second heaters 321 and 322 do not overlap.

  In the above embodiment, it is described that an image is formed on one side of the transfer paper 212 and the image is fixed. However, the same applies to the case where images are formed on both sides of each side. In this case, the image forming surface on the non-fixing side comes into contact with the pressure roller 340.

Further, the heat capacity of the heating member is set such that the heat capacity of the heating member <the heat capacity of the pressure member. Here, the heating member corresponds to a member directly involved in heating, that is, the heating roller 320 and the fixing belt 330, and the pressure member corresponds to a member that applies pressure, that is, the pressure roller 340 and the fixing roller 310. . With this configuration, since the heat capacity on the pressure member side is large and the heat fluctuation is small, the fixing state can be controlled by heating control using a plurality of heat sources on the heating member side. Therefore, the pressure heater 341 which is a heating source on the heating member side. It is possible to sufficiently control the temperature of the fixing unit 300 without using a plurality of.

  Other parts that are not particularly described are configured in the same manner as the first embodiment and function in the same manner.

  As described above, according to the present embodiment, the following effects can be obtained.

  That is, when the fixing unit 300 passes the paper, the pressure heater 341 is turned off regardless of whether the heaters 321 and 322 are turned on or off. Therefore, the heaters 321 and 322 are controlled by turning the pressure heater 341 on / off. Simple control that does not depend on the off state can be achieved.

  When the temperature of the fixing unit 300 is increased before passing through the fixing heater, since the pressure heater 341 is turned off regardless of whether the heaters 321 and 322 are turned on or off, the heaters 321 and 322 are controlled. It is possible to make simple control independent of the state.

  There are two or more heaters 321 and 322, and these heaters are controlled so that they may overlap each other when the paper is passed, so that the heater is reduced while reducing the maximum power consumption and enabling compliance with flicker regulations. The control of 341 can be a simple control that does not depend on the state of each other.

  There are two or more heaters 321 and 322, and control is performed so that the ON state may overlap each other even when the temperature of the fixing unit 300 is increased before the heater passes through, so that the maximum power consumption is reduced and flicker regulation is performed. The heater control at the time of passing the sheet to the fixing unit 300 can be made simple control independent of the state of each other.

  When the fixing unit 300 is on standby, the ON / OFF control is performed so that the ON state of the pressure heater 341 and the heaters 321 and 322 does not overlap, so that the maximum power consumption can be reduced and the flicker regulation can be supported. it can.

  There are two or more heaters 321 and 322, and they are controlled so that they may overlap each other when the paper is passed. Therefore, while reducing the maximum power consumption and making it possible to meet the flicker regulations, Control of the heaters 321 and 322 at the time of paper feeding can be made simple control independent of the state of each other.

  Since at least one of the plurality of heaters 321 and 322 has a light distribution characteristic at the center, and at least one of the other heaters is divided into end heaters having a light distribution characteristic at the end, and the functions are divided. Maximum power consumption can be reduced and flicker regulations can be met.

  Since the heaters 321 and 322 are included in the heating roller 320 that is rotated by the fixing belt 330, the structure of the heaters 321 and 322 can be simplified and the thermal efficiency can be improved.

  Since the pressure heater 341 that heats the pressure roller 340 heats the back side of the image on the transfer paper 212, the fixing structure can be effectively used for heat fixing.

  Since the heat capacity of the heating member is (heat capacity of the heating member) <(heat capacity of the pressure member), a plurality of pressure heaters 341 need not be provided.

1 is a diagram illustrating a schematic configuration of a color printer as a color image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a diagram illustrating a detailed configuration of the fixing device illustrated in FIG. 1. FIG. 3 is a block diagram illustrating a portion related to the fixing device of the control circuit of the color printer according to the first exemplary embodiment of the present invention. It is a flowchart which shows the control procedure of the control performed in the 1st Embodiment of this invention. It is a timing chart which shows an example of the control timing of the control performed in the 1st embodiment of the present invention. It is a flowchart which shows the control procedure of the control performed in the 2nd Embodiment of this invention. It is a timing chart which shows an example of the control timing of the control performed in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Image forming part 105 Vertical conveyance path 200 Paper feed part 212 Transfer paper 300 Fixing device (unit)
310 Fixing roller 320 Heating rollers 321 and 322 Heating heater 330 Fixing belt 340 Pressing roller 341 Pressing heater 350 First temperature detection sensor 351 Second temperature detection sensor 400 Paper discharge unit 610 Unfixed toner image 620 Fixing toner image 700 Control circuit 701 Control unit

Claims (12)

By passing the recording medium between the first rotating member and second rotating member, the fixing device for fixing an image on the recording medium,
A pair of the heating source for heating the first rotary member, before Symbol a first temperature detecting means for detecting the surface temperature of the first rotating body, heat the pre Symbol second rotor pressurizing a pressure heat source, based on the previous SL second and the second temperature detecting means for detecting the surface temperature of the rotating member, before Symbol temperature sensed by said first temperature sensing means a second temperature sensing means and control means for controlling each of the heating amount of said pressurized hot source and the pair of the heating source Te,
The control means turns on the pressure heat source and one heating source of the pair of heating sources in this order at the time of fixing standby, and when the one heating source is turned off, the other of the pair of heating sources is turned on. A fixing device that performs control to turn on a heating source . In a fixing device for fixing an image on a recording medium by passing the recording medium between the first rotating body and the second rotating body,
A pair of heating sources for heating the first rotating body, a first temperature detecting means for detecting a surface temperature of the first rotating body, and a pressurized heat source for pressing and heating the second rotating body And a pair of heating based on the temperature detected by the second temperature detecting means for detecting the surface temperature of the second rotating body, the first temperature detecting means and the second temperature detecting means. Control means for controlling the heating amount of the source and the pressurized heat source, respectively,
The control means turns on one heating source and the other heating source of the pair of heating sources in this order when passing the recording medium, and turns off both the one heating source and the other heating source. constant Chakusochi Once you and performs a control to turn on the hot compressed source. The fixing device according to claim 2, wherein the control means, the passage before during heating of the recording medium, a constant Chakusochi you and performing control to turn off the pressurized heat source. 4. The fixing device according to claim 1, wherein one of the pair of heating sources is a central heater having a light distribution characteristic at a central portion, and the other is a light distribution at an end portion. constant Chakusochi you, wherein the characteristic is an end heater having. The fixing device of any of claims 1-4, wherein the pair of heating source, you characterized in that provided in said first rotary member to turn over the fixing belt constant Chakusochi . The fixing device according to any one of claims 1 to 5, wherein the first rotating body is constant Chakusochi you characterized by heating the imaging surface comprising a fixing target of the recording medium. 7. The fixing device according to claim 1, wherein the second rotating body is in contact with a non-image forming surface of the recording medium or an image forming surface that is not a fixing target, and the pressure is applied. the heat source, the you an image forming surface side that is not a non-image forming surface side or the fixing target recording medium, wherein the heating under pressure constant Chakusochi. 8. The fixing device according to claim 1, wherein the heat capacity of a heating member that is heated by the pair of heating sources and contacts a fixing target side and a pressure member that pressurizes the recording medium is heated. constant Chakusochi you characterized in that set in the heat capacity becomes relation capacity <pressing member of members. An image forming apparatus comprising the fixing device according to claim 1. In a heating control method of a fixing device for fixing an image on the recording medium by passing the recording medium between the first rotating body and the second rotating body,
One heating source of a pressure heat source that pressurizes and heats the second rotating body and a pair of heating sources that heat the first rotating body at the time of fixing the recording medium is turned on in this order. A heating control method for a fixing device, comprising: controlling to turn on the other heating source of the pair of heating sources when the heating source is turned off. In a heating control method of a fixing device for fixing an image on the recording medium by passing the recording medium between the first rotating body and the second rotating body,
One heating source and the other heating source of the pair of heating sources that heat the first rotating body when the recording medium passes are turned on in this order, and both the one heating source and the other heating source are turned off. heating control method of the fixing device and performs a control to turn on the pressurized hot source for heating presses the second rotating body at the time of the. 12. The heating control method for a fixing device according to claim 11, wherein control is performed to turn off the pressure heat source when the temperature of the recording medium is increased before passing.

Images