JP6540133B2 - Fixing device and image forming apparatus - Google Patents

Description

  The present invention relates to a fixing device and an image forming apparatus.

Patent Document 1 discloses a configuration in which the deformation member expands with the temperature rise of the temperature-sensitive magnetic member, and the expansion causes the temperature-sensitive magnetic member to contact the fixing belt.
In Patent Document 2, heating is started in a state where the temperature sensitive member is separated from the heat generating member before the temperature of the temperature sensitive member reaches the heating set temperature or more, and the temperature sensitive member reaches the heating set temperature or more. There is disclosed a configuration in which the temperature sensitive member is brought into contact with the heat generating member after the heat treatment.

JP, 2013-20216, A Unexamined-Japanese-Patent No. 2009-282413

In the fixing device, when the member to be heated is brought into contact with the fixing member after the fixing process is completed, the fixing member is hard to cool, and the temperature decrease until the next fixing process can be suppressed. Further, at the time of warm-up, in order to shorten the heating time, the members to be heated are separated and heating is performed.
However, since it takes time to separate the members to be heated, the fixing member may come into contact with the fixing member at the start of the warm-up. At this time, if the temperature of the member to be heated is lower than the predetermined temperature, even if heating of the fixing member is started, the heat of the fixing member is absorbed by the member to be heated in the cold state, so the warm-up time is delayed.
An object of the present invention is to suppress an increase in warm-up time due to the temperature of a heated member in contact with a fixing member falling below a predetermined temperature.

The invention according to claim 1 comprises a fixing member for fixing an image on a recording material to the recording material, a heated member disposed so as to face the fixing member and constituted by a temperature-sensitive magnetic member, and the fixing. Print job with heating means for electromagnetic induction heating the member and the member to be heated, contact / separation means for separating and contacting the member to be heated to the fixing member, and the fixing member and the member to be heated being in contact with each other the first case above temperature, the heated member and the fixing member fixing operation was performed a temperature of our Keru the heated member after the completion is predetermined with respect to the temperature of the heated member itself depending on without spacing between, when the member to be heated is lower than the first temperature, the member to be heated is separated from the fixing member, further, the object to be heated when a new print job is received The member is the fixing unit Until when you are in contact, the member to be heated and a control means for separating from the fixing member, the new print job after the fixing operation is completed is received, When the temperature of the heated member which has exceeded the first temperature becomes lower than the first temperature, the heated member is removed from the fixing member without waiting for the reception of the new print job. The fixing device is a fixing device that separates the heated member from the fixing member at the time of reception of the new print job .
The invention according to claim 2 is a fixing member for fixing an image on a recording material to the recording material, a heated member disposed so as to face the fixing member and constituted by a temperature-sensitive magnetic member, and the fixing. Print job with heating means for electromagnetic induction heating the member and the member to be heated, contact / separation means for separating and contacting the member to be heated to the fixing member, and the fixing member and the member to be heated being in contact with each other When the temperature of the heated member is equal to or higher than the first predetermined temperature after the fixing operation performed in accordance with the above is completed, the contact state between the heated member and the fixing member is maintained, and the heated member When the temperature is lower than the first predetermined temperature, the control unit controls the contact / separation unit to separate the heated member from the fixing member, and when a new print job is received, The heated member and the fixing If the the wood are in contact, the member to be heated is separated from the fixing member by said control means, in a state where the heated member is separated from the fixing member, a fixing apparatus for heat by the heating means It is.
The invention according to claim 3 is a fixing member for fixing an image on a recording material to the recording material, a heated member disposed so as to face the fixing member and constituted by a temperature-sensitive magnetic member, and the fixing Print job with heating means for electromagnetic induction heating the member and the member to be heated, contact / separation means for separating and contacting the member to be heated to the fixing member, and the fixing member and the member to be heated being separated in after fixing operation was performed has been completed according to, the temperature of the heating member is equal to or larger than a first predetermined temperature is brought into contact with the heated member and the fixing member, the member to be heated is the first when the case of less than a predetermined temperature which has a control means for controlling said moving means so as to maintain a state in which the heated member is separated from the fixing member, and receives a new print job , The heated member and the front In the case where the fixing member are in contact, the member to be heated is separated from the fixing member by said control means, in a state where the heated member is separated from the fixing member, performing the heating by the heating means fixing It is an apparatus.
The invention according to claim 4 is the fixing device according to any one of claims 1 to 3 , further comprising a heated member temperature detection means for detecting the temperature of the heated member .
The invention according to claim 5 is the fixing device according to any one of claims 1 to 4 , further comprising fixing member temperature detection means for detecting the temperature of the fixing member .
According to a sixth aspect of the present invention, there is provided a fixing member for fixing an image on a recording material to the recording material, a heated member disposed so as to face the fixing member and constituted of a temperature-sensitive magnetic member, and the fixing. Print job with heating means for electromagnetic induction heating the member and the member to be heated, contact / separation means for separating and contacting the member to be heated to the fixing member, and the fixing member and the member to be heated being in contact with each other When the temperature of the heated member is equal to or higher than the first predetermined temperature after the fixing operation performed in accordance with the above is completed, the contact state between the heated member and the fixing member is maintained, and the heated member If the temperature is lower than the first predetermined temperature, the control means controls the contact / separation means to separate the heated member from the fixing member, and the control means performs a new print job the object to be heated when the received If the temperature of wood and the fixing member are in contact and the member to be heated is lower than a higher second predetermined temperature than the first predetermined temperature, is separated the heated member from the fixing member, the If the temperature of the heating member is equal to or greater than the second predetermined temperature is a fixing device not the member to be heated is separated from the fixing member.
The invention according to claim 7 comprises an image forming means for forming an image on a recording material, a fixing member for fixing an image formed on the recording material by the image forming means to the recording material, and the fixing member. a heated member configured by arranged thermosensitive magnetic member so as to, wherein the fixing member and the heating member and the heating means for electromagnetic induction heating, contact to separate and contacting said heated member to the fixing member After the fixing operation performed according to the print job is completed in a state in which the fixing unit and the heated member are in contact with each other, the heated member is heated when the temperature of the heated member is equal to or higher than a predetermined temperature. Control means for maintaining contact between the member and the fixing member, and controlling the contact / separation means to separate the heat receiving member from the fixing member when the heating member is below a predetermined temperature; have, new If the heated member and the fixing member are in contact with each other when the print job is received, the control member separates the heated member from the fixing member, and the heated member fixes the fixed member. The image forming apparatus may perform heating by the heating unit in a state of being separated from a member .

According to the invention of claim 1 or 2, compared with the case where the temperature of the heated member left in contact with the fixing member heated member be lowered below a predetermined temperature, due to temperature drop of the heated member An increase in warm-up time can be suppressed.
According to the invention of claim 3, it is possible to suppress an increase in the warm-up time.
According to the invention of claim 4 , the temperature of the member to be heated is made more accurate than in the case where the temperature of the member to be heated is indirectly detected by detecting the temperature of another member different from the member to be heated. I can understand.
According to the fifth aspect of the present invention, the temperature of the member to be heated can be detected without directly detecting the temperature of the member to be heated.
According to the invention of claim 6 , the warm-up time is higher than in the case where the heated member is separated from the fixing member when the temperature of the heated member is equal to or higher than the second predetermined temperature higher than the first predetermined temperature. To reduce power consumption.
According to the invention of claim 7 , even when the temperature of the heated member is lowered below the predetermined temperature, the warm-up caused by the temperature decrease of the heated member as compared with the case where the heated member is kept in contact with the fixing member. An increase in time can be suppressed.

FIG. 1 is a diagram showing an entire configuration of an image forming apparatus of the present embodiment. It is a figure explaining a fixing device. FIG. 6 is a diagram showing the state of the fixing device in the heat storage mode. It is a figure which compares a rapid-heating mode and a thermal storage mode. It is the figure which showed the correlation of a rapid-heating mode and a thermal storage mode. FIG. 6 is a diagram showing an example of processing executed by the image forming apparatus. FIG. 7 is a view showing processing executed at the time of remote printing in step 104 of FIG. 6; 5 is a flowchart showing the flow of processing executed when a job ends. FIG. 9 is a diagram showing the temperature of the fixing belt when the process shown in FIG. 8 is performed.

FIG. 1 is a view showing the overall configuration of an image forming apparatus 10 of the present embodiment.
The image forming apparatus 10 includes an image forming unit 240 as an example of an image forming unit that forms an image on a sheet P as a recording material, and an image reading unit 238 that reads an image on a document G. Furthermore, a UI (User Interface) 230 configured of a touch panel or the like is provided. The UI 230 displays information to the user and receives information input from the user.
Further, in the image forming apparatus 10, a control unit 200 that controls each part of the image forming apparatus 10 is provided. In other words, the control unit 200 is provided to control the image forming operation and the fixing process. The control unit 200 is configured of a program-controlled CPU.

  A document conveying device 12 that automatically conveys a plurality of documents G one by one, a first platen glass 16 on which the document G is placed, and a document conveying device 12 are carried on the top of the device body 10A of the image forming device 10. An image reading unit 238 is provided which reads the document G or the document G placed on the first platen glass 16. Further, the document conveyance device 12 is provided with a document table 13 on which a plurality of documents G are placed.

  The image reading unit 238 is provided with a first mirror unit 18 which moves along the first platen glass 16. Furthermore, a second mirror unit 22 for reflecting light from the first mirror unit 18 (reflected light from a document) is provided. The light from the second mirror unit 22 passes through the lens 24 and travels to the imaging device 26 such as a CCD line sensor.

  An image forming unit 240 for forming an image on the sheet P is provided at the center in the vertical direction of the apparatus main body 10A. The image forming unit 240 is provided with a plurality of image forming units 30 for forming toner images of different colors. As the image forming unit 30, four image forming units 30Y, 30M, 30C, and 30K of yellow (Y), magenta (M), cyan (C), and black (K) are provided.

On the upper side of each image forming unit 30, an intermediate transfer belt 32 to which the toner image generated by each image forming unit 30 is transferred is provided. The intermediate transfer belt 32 circulates in the arrow A direction.
Each image forming unit 30 includes a photosensitive drum 34 for holding a toner image to be formed, a charging member 36 for charging the photosensitive drum 34, an exposure device 40 for exposing the photosensitive drum 34, and an exposure device 40. A developing device 42 is provided which adheres toner to the electrostatic latent image generated on the photosensitive drum 34 to form a toner image.

A primary transfer member 46 used for transferring the toner image formed on the photosensitive drum 34 to the intermediate transfer belt 32 is provided on the opposite side of the photosensitive drum 34 with the intermediate transfer belt 32 interposed therebetween.
Further, each image forming unit 30 is provided with a cleaning device 44 for removing toner and the like remaining on the photosensitive drum 34 without being transferred from the photosensitive drum 34 to the intermediate transfer belt 32.

At the time of image formation, first, light based on image data of each color is emitted from an exposure device 40 provided in each of the image forming units 30Y, 30M, 30C, and 30K. The light exposes the surface of the photosensitive drum 34 of each color charged by the charging member 36, and an electrostatic latent image is formed on the surface of the photosensitive drum 34.
The electrostatic latent image formed on the surface of the photosensitive drum 34 is developed by the developing device 42 as a toner image of each color.

  The toner images of the respective colors of yellow (Y), magenta (M), cyan (C) and black (K) formed on the surface of the photosensitive drum 34 are transferred onto the intermediate transfer belt 32 by the primary transfer member 46. Ru. At this time, the toner images of the respective colors are transferred onto the intermediate transfer belt 32 in a state of being superimposed on each other.

  Inside the intermediate transfer belt 32, a drive roll 48 for driving the intermediate transfer belt 32, a support roll 50 for supporting the intermediate transfer belt 32 from the inside, a tension applying roll 54 for applying tension to the intermediate transfer belt 32, an intermediate transfer belt 32 are provided with idler rolls 56, 58 placed in contact.

Further, on the opposite side of the driving roller 48 with the intermediate transfer belt 32 interposed therebetween, a cleaning device 52 for cleaning the intermediate transfer belt 32 is provided.
Further, a secondary transfer member 60 for transferring the toner image on the intermediate transfer belt 32 to the sheet P is disposed on the opposite side of the support roll 50 with the intermediate transfer belt 32 interposed therebetween. Hereinafter, in the present specification, this portion where the toner image on the intermediate transfer belt 32 is transferred to the sheet P is referred to as a secondary transfer portion T2.

A fixing device 64 is provided above the secondary transfer member 60. The sheet P on which the toner image has been transferred by the secondary transfer member 60 reaches the fixing device 64. The fixing device 64 applies pressure and heat to the sheet P to fix the toner image on the sheet P.
The fixing device 64 is provided with a fixing belt unit 64A disposed on the image surface side of the sheet P, and a pressure roll 64B for pressing the sheet P toward the fixing belt unit 64A.

On the downstream side of the fixing device 64 in the conveyance direction of the sheet P, a first discharge unit 69 and a second sheet discharge unit 72 are provided to discharge the fixed sheet P.
Further, a gate 68 is provided to switch the discharge destination of the sheet P to either the first discharge portion 69 or the second sheet discharge portion 72. Further, on the downstream side of the fixing device 64, a plurality of transport rolls 73 for transporting the sheet P are provided.

  On the other hand, at the lower part of the apparatus main body 10A, on the upstream side of the secondary transfer member 60 in the sheet conveyance direction, sheet feeding sections 80, 82, 84, 86 are provided. In each of the sheet feeding units 80, 82, 84, and 86, the sheet P is accommodated.

Each of the paper feed units 80, 82, 84, 86 is provided with a paper feed roll 88 for feeding the stored paper P. Further, on the downstream side of the paper feed roll 88, a transport roll 90 for further transporting the sheet P and a transport roll 92 are provided.
Further, on the downstream side of the transport roll 92, there is provided a delivery roll 94 for stopping the sheet P at one end and delivering the sheet P to the secondary transfer portion T2 at a predetermined timing.

FIG. 2 is a view for explaining the fixing device 64. As shown in FIG.
The fixing device 64 is provided with a fixing belt unit 64A disposed on the image surface side of the sheet P, and a pressure roll 64B for pressing the sheet P toward the fixing belt unit 64A.

The fixing belt unit 64A is provided with an endless fixing belt 302. The fixing belt 302 functions as a fixing member, and is used to fix the toner image on the sheet P.
Cylindrical cap members (not shown) are fitted at both ends in the width direction of the fixing belt 302. In the present embodiment, both ends of the fixing belt 302 are supported via the cap member. Further, a gear rotated by a motor (not shown) meshes with one of the cap members. When the motor rotates, the fixing belt 302 rotates in the direction indicated by the arrow 2A.

  At a position facing the outer peripheral surface of the fixing belt 302, a bobbin 308 made of an insulating material is disposed. The bobbin 308 is formed to follow the outer peripheral surface of the fixing belt 302 and has an arc shape. The bobbin 308 is provided with a convex portion 308A which protrudes in a direction away from the fixing belt 302. The distance between the bobbin 308 and the fixing belt 302 is set to, for example, 1 to 3 mm.

An exciting coil 310 is wound around the bobbin 308 to generate a magnetic field by energization. Specifically, it is wound around the convex portion 308A.
Further, in the present embodiment, the magnetic core 312 is disposed at a position facing the exciting coil 310. The magnetic core 312 has a shape that follows the shape of the bobbin 308.

The fixing belt 302 has a base layer, a heat generating layer, an elastic layer, and a releasing layer.
The base material layer is made of a material that has strength to support the heat generating layer, is heat resistant, penetrates the magnetic field (magnetic flux), and does not generate heat or hardly generates heat by the action of the magnetic field. For example, a polyimide belt can be used.
The heat generating layer is made of a metal material through which an eddy current flows so that the magnetic field (AC magnetic field) generated by the exciting coil 310 passes in the thickness direction and generates a magnetic field that cancels the magnetic field. Specifically, for example, a metal material of gold, silver, copper, aluminum, zinc, tin, lead, bismuth, beryllium, antimony, or an alloy thereof can be used.

As the elastic layer, silicon rubber or fluorine rubber is used from the viewpoint of obtaining elasticity and heat resistance.
The release layer is provided on the outermost layer of the fixing belt 302 and weakens the adhesive force between the toner image on the sheet P and the fixing belt 302 so that the sheet P can be easily peeled off from the fixing belt 302. As the release layer, fluorine resin, silicon resin, polyimide resin or the like can be used.

  Inside the fixing belt 302, a temperature-sensitive magnetic member 314 disposed so as to face the fixing belt 302 is provided. The temperature sensitive magnetic member 314 has a shape that follows the inner peripheral surface of the fixing belt 302, and contacts the inner peripheral surface of the fixing belt 302.

  The magnetic permeability of the temperature-sensitive magnetic member 314 starts to decrease continuously from the permeability change start temperature in the temperature range (temperature range) not less than the fixing set temperature of the fixing belt 302 and not more than the heat resistant temperature of the fixing belt 302. It has temperature sensitive characteristics. A specific material is, for example, a binary magnetizable alloy steel such as Fe-Ni alloy (Permalloy) or Fe-Ni-Cr alloy whose permeability change start temperature is set in a range of 140 to 240 ° C., for example. A ternary system of magnetic shunt steel or the like is used.

  The temperature sensitive magnetic member 314 is disposed opposite to the exciting coil 310 functioning as a heating unit, and is heated together with the fixing belt 302 by receiving a magnetic field. In addition, in the present embodiment, the temperature-sensitive magnetic member 314 and the fixing belt 302 are heated by electromagnetic induction heating. Here, the temperature-sensitive magnetic member 314 can be regarded as a heated member.

  Inside the temperature sensitive magnetic member 314, a derivative 318 made of aluminum is provided. The derivative 318 is desirably a nonmagnetic metal having a thickness equal to or greater than the skin depth and low in specific resistance, and silver, copper, or aluminum can be used as the material. The derivative 318 is disposed at a position that induces the magnetic flux penetrating the temperature sensitive magnetic member 314.

  Furthermore, the derivative 318 is provided with a pressed portion 318A that is pressed by a cam 66A described later. The pressed portion 318A is connected to the main body 318B of the derivative 318. Further, the pressed portion 318A is disposed so as to extend in the inward direction of the fixing belt 302 starting from a point connected to the main body 318B.

  Furthermore, in the present embodiment, the derivative 318 and the temperature-sensitive magnetic member 314 are connected at both ends of the temperature-sensitive magnetic member 314 in the drawing. In other words, the temperature-sensitive magnetic member 314 has one end 314A located on the right side in the figure and the other end 314B located on the left side in the figure, but at the one end 314A and the other end 314B, The derivative 318 and the temperature sensitive magnetic member 314 are connected. In the present embodiment, the temperature-sensitive magnetic member 314 moves (details will be described later). At this time, the derivative 318 and the temperature-sensitive magnetic member 314 move integrally.

Inside the fixing belt 302, a support frame F is provided. The derivative 318 and the temperature sensitive magnetic member 314 are supported by the support frame F.
Further, at the lower part of the support frame F, a pressing pad 332 is provided. The pressing pad 332 presses the fixing belt 302 in the outward direction of the fixing belt 302. In the present embodiment, the pressure roller 64 B is pressed against the pressing pad 332. The pressing pad 332 is formed of an elastic material such as urethane rubber or sponge.

  Further, an advancing and retracting mechanism 66 for advancing and retracting the temperature sensitive magnetic member 314 and the derivative 318 with respect to the inner peripheral surface of the fixing belt 302 is provided. The advancing and retracting mechanism 66 functions as contact / separation means for moving the temperature sensitive magnetic member 314 into and out of contact with the fixing belt 302. In the present embodiment, contact of the temperature sensitive magnetic member 314 with the fixing belt 302 and separation of the temperature sensitive magnetic member 314 from the fixing belt 302 are performed by the advancing and retracting mechanism 66.

  The advancing and retracting mechanism 66 is provided with a biasing member (not shown) for biasing the temperature-sensitive magnetic member 314 and the derivative 318 on the side opposite to the support frame F (toward the inner circumferential surface of the fixing belt 302). ing. Further, the advancing and retracting mechanism 66 is provided with a cam 66A that functions as a pressing member and presses the pressed portion 318A. Furthermore, a motor M for rotating the cam 66A is provided.

The biasing member is constituted by, for example, a coil spring, and biases the temperature sensitive magnetic member 314 and the derivative 318 on the side opposite to the support frame F side. In addition, the temperature sensitive magnetic member 314 and the derivative 318 are energized toward the upper side in the figure. Thus, in the present embodiment, the temperature-sensitive magnetic member 314 contacts the inner circumferential surface of the fixing belt 302.
The cam 66A presses the pressed portion 318A and moves the temperature-sensitive magnetic member 314 and the derivative 318 in a direction away from the inner circumferential surface of the fixing belt 302. As a result, the temperature-sensitive magnetic member 314 is separated from the inner circumferential surface of the fixing belt 302.

A pressure roller 64 B is pressed against the outer peripheral surface of the fixing belt 302. The pressure roller 64B follows the fixing belt 302 and rotates in the direction indicated by the arrow 2B. The pressure roller 64B includes a core 306 made of metal such as aluminum and an elastic layer 307 disposed around the core 306. Is provided.

The elastic layer 307 is made of, for example, a foamed silicone rubber sponge having a thickness of 5 mm. Further, on the outside of the elastic layer 307, a release layer made of carbon-containing PFA is formed.
Further, in the present embodiment, a retract mechanism (not shown) for separating the pressure roller 64B from the fixing belt 302 is provided.

Inside the fixing belt 302, a belt thermistor 334 is provided as an example of a temperature detecting unit that detects (measures) the temperature of the fixing belt 302.
Furthermore, in the present embodiment, a thermistor 335 for a temperature-sensitive magnetic member is provided as an example of a temperature detection unit that detects the temperature of the temperature-sensitive magnetic member 314.

The belt thermistor 334 is in contact with the inner circumferential surface of the fixing belt 302. Further, the belt thermistor 334 is positioned in the area not facing the exciting coil 310 and in the area on the paper P discharge side.
Further, a plurality of belt thermistors 334 are provided and arranged in the width direction of the fixing belt 302. Thus, in the present embodiment, the temperature of the fixing belt 302 is detected at a plurality of locations in the width direction of the fixing belt 302.

The belt thermistor 334 detects the surface temperature of the fixing belt 302 by converting the resistance value changed according to the amount of heat supplied from the fixing belt 302 into a temperature.
The belt thermistor 334 is connected to the control unit 200 (see FIG. 1). The control unit 200 performs temperature conversion based on the electric signal sent from the belt thermistor 334 to grasp the temperature of the fixing belt 302. Then, the detected temperature is compared with a predetermined fixing temperature (for example, 170 ° C.), and if the detected temperature is lower than the fixing setting, the exciting coil 310 is energized to generate a magnetic field. . If the detected temperature is higher than the fixing temperature, the energization is stopped.

  A plurality of the temperature sensitive magnetic member thermistors 335 are also provided, and arranged in the width direction of the fixing belt 302. Thus, in the present embodiment, the temperature of the temperature-sensitive magnetic member 314 is detected at a plurality of locations in the width direction of the fixing belt 302. Furthermore, also in the temperature-sensitive magnetic member thermistor 335, the temperature of the temperature-sensitive magnetic member 314 is detected by converting the resistance value changed according to the amount of heat supplied from the temperature-sensitive magnetic member 314 into a temperature.

  Here, as the fixing mode, the fixing device 64 of the present embodiment is a “heat storage mode” which is a first fixing mode in which the fixing process is performed in a state where the temperature sensitive magnetic member 314 is in contact with the fixing belt 302; The temperature sensitive magnetic member 314 is separated from the fixing belt 302, and has a "fast heat mode" which is a second fixing mode in which the fixing process is performed.

In the heat storage mode, as shown in FIG. 3 (a diagram showing the state of the fixing device 64 in the heat storage mode), the cam 66A is in a lying state, and it is felt that it is biased by a biasing member (not shown). The heat magnetic member 314 contacts the inner circumferential surface of the fixing belt 302.
On the other hand, in the rapid thermal mode, as shown in FIG. 2, the cam 66A is in a standing state, and the temperature sensitive magnetic member 314 is separated from the fixing belt 302.

Here, as described above, the fixing device 64 of the present embodiment includes the “fast heat mode” and the “heat storage mode” as the fixing mode, and basically, the number of sheets P on which the fixing process is to be performed. In response, one of these two modes is set (selected).
In the present embodiment, the control unit 200 rotationally drives the cam 66A to set (switch) the fixing mode.

FIG. 4 is a diagram comparing the fast heat mode with the heat storage mode.
Here, in the "fast heat mode", the warm-up time is shortened. On the other hand, the number of sheets of paper P that can be processed per unit time decreases. In the "heat storage mode", the warm-up time becomes long. On the other hand, the number of sheets of paper P that can be processed per unit time increases.
For this reason, the "fast heat mode" is suitable for small amount processing of one to several sheets (hereinafter, referred to as "N ₀ sheets"). On the other hand, the "heat storage mode" is suitable for mass processing of the number of sheets exceeding N ₀ sheets.

(Processing when the number of processed sheets is known at the start of fixing)
Here, in the present embodiment, when the number of processed sheets of paper P (the number of sheets of paper P to be subjected to the fixing process) in one job is known (when the number of processed sheets is known before starting the fixing process) Before starting the process, a fixing mode is selected which minimizes the processing time.

Specifically, in the present embodiment, either the fast heat mode or the heat storage mode is selected depending on whether the following equation (1) is satisfied. More specifically, the fast heat mode is selected when the equation (1) is established, and the heat storage mode is selected when the equation is not established.
W1 + F1 + P1 × N <W2 + F2 + P2 × N (1)

here,
N: Number of processed sheets of image processing F1: Time from the operation of the copy start button in the fast heat mode to the discharge of the first sheet P to the first discharge portion 69 (First Copy Output Time / FCOT)
F2: Time from the operation of the copy start button in the heat storage mode to the discharge of the first sheet P to the first discharge portion 69 (First Copy Output Time / FCOT)
P1: Processing time per sheet in the rapid heating mode P2: Processing time per sheet in the thermal storage mode W1: Warm-up operation time in the rapid heating mode (warm up time)
W2: Warm-up operation time of heat storage mode (warm-up time)
It is.

FIG. 5 is a diagram showing the correlation between the fast heat mode and the heat storage mode. The horizontal axis indicates the number of processed sheets, and the vertical axis indicates time.
As shown in FIG. 5, the rapid thermal mode characteristic curve S, which is a characteristic curve for the rapid thermal mode, maintains a directly proportional characteristic with a slope dependent on P1 after the warm-up time (W1 + F1) has elapsed. The heat storage mode characteristic curve C maintains a directly proportional characteristic with a slope dependent on P2 after the warm-up time (W2 + F2) has elapsed.

  In FIG. 5, since the number of processed sheets is on the horizontal axis and the time is on the vertical axis, it means that the processing takes more time as the inclination is larger. Here, in the present embodiment, the slope of the rapid thermal mode characteristic curve S is larger than that of the heat storage mode characteristic curve C.

In the present embodiment, since the slope (P1) of the rapid thermal mode characteristic curve S and the slope (P2) of the thermal storage mode characteristic curve C are different, both (the rapid thermal mode characteristic curve S and the thermal storage mode characteristic curve C) are It will cross. The location where the intersection occurs (location indicated by the symbol K in FIG. 5) is the number of sheets (processing number N ₀ ) at the boundary as to whether the fixing mode is the fast heat mode or the heat storage mode. The boundary is, for example, 10 sheets. In this case, the fast heat mode is selected up to 10 processed sheets, and the heat storage mode is selected if the processed sheets exceed 11 sheets.

(Processing when the number of processed sheets is unknown at the start of fixing)
On the other hand, when copying processing of a large amount of documents G is performed, the number of processed sheets is unknown at the time of starting fixing processing, and at the time of starting processing, it is difficult to determine by the above equation (1). Become. Therefore, in the present embodiment, when the number of processed sheets is unknown at the start of the fixing process, the process described below is performed.

  Here, the job performed in the image forming apparatus 10 includes copying and remote printing, and also, for example, “print anywhere” as on-demand processing.

“Copying” is a process in which the image forming unit 240 forms an image on the sheet P while reading the document G by the image reading unit 238 (see FIG. 1).
In the "copying" process, the number of sheets P to be fixed is unknown at the start of the copying process, and the selection of the fixing mode (selection based on the equation (1) at the time of starting the copying process. ) Can not do.
In the image forming apparatus 10, the power saving mode or the like is provided, but when the power saving mode is released, there is no information on copying. For this reason, it is not possible to select the fixing mode even when the power saving mode is released.

  If the copying process is started after waiting until all the document G is read, the number of processed sheets is known before the fixing process is started, but in this case, the entire processing time becomes long. Therefore, in general, the image forming process (fixing process) is performed in parallel with the image reading process.

Besides the copying process, there is also a process called "remote printing".
In “remote printing”, the image forming apparatus 10 receives image information and print type (number of pages, number of copies, N-up, etc.) from a PC (Personal Computer) or the like. In this "remote printing", the number of processed sheets can be recognized, and the number of processed sheets is known before the fixing process is started. Therefore, either the fast heat mode or the heat storage mode can be set before the fixing process is started.

Next, "print anywhere" will be described.
In "anywhere print", image information stored in a PC, a server or the like is output using the image forming apparatus 10 near the user. When the user operates the image forming apparatus 10, image information is output from the storage destination to the image forming apparatus 10, and the image forming apparatus 10 forms an image on the sheet P. In printing anywhere, selection of the fixing mode (selection based on the equation (1)) can not be performed when the power saving mode is released.

  Here, in the present embodiment, there is a case where the selection of the fixing mode may not be performed as described above. In this case, the fixing process is first started in the fast thermal mode. Then, based on the number of processed sheets to be found after that, the fixing mode is selected again and the fixing process is continued. Here, in this process, a process of taking over the fast heat mode, which is the first mode, or a process of switching from the fast heat mode to the heat storage mode is performed.

FIG. 6 is a diagram showing an example of processing executed by the image forming apparatus 10. As shown in FIG. Note that this process is performed by the control unit 200.
First, at step 100, it is judged whether or not the power saving mode is recovered, and if the negative judgment is made, the power saving mode is maintained and this routine is ended. If an affirmative determination is made in step 100, the process proceeds to step 102 to determine the type of job.

  If it is determined in step 102 that the received job is remote printing, the process proceeds to step 104 to perform fixing processing in the remote print fixing mode. The fixing process in the remote print fixing mode will be described later.

On the other hand, when it is determined in step 102 that the received job is copying (copying), switching processing to the rapid thermal mode is executed (step 106).
In this switching process, as shown in FIG. 2, the cam 66A is in a standing state. In this case, the temperature sensitive magnetic member 314 is separated from the fixing belt 302.

  In the next step 107, it is judged whether or not there is a copy start instruction (operation of the start button), and if it is judged that there is a copy start instruction, the process proceeds to step. In step 108, the image reading unit 238 starts reading the document G.

Next, the process proceeds to step 118, where an initial movement process is started.
In the initial movement process of step 118, the fixing process in the rapid thermal mode is performed. In this initial movement process, since the fast heat mode is used, as shown in FIG. 4, the warm-up time is as short as 3 to 6 seconds and can be fixed immediately, and the document G is read while the document P is read. Image formation can be performed.

On the other hand, if the received job is other than remote printing and copying in step 102, more specifically, for example, if "print anywhere", the process proceeds to step 110. Thereafter, the UI 230 (see FIG. 1) is operated by the user, and an instruction to execute image formation is issued by the user. In step 110, it is determined whether or not the instruction to execute image formation has been issued.
If it is determined in step 110 that there is no execution instruction, the standby process is performed in step 112, and then the entire process ends. The standby process refers to a process of acquiring information having a large amount of information such as an image.

On the other hand, when it is determined in step 110 that there is an execution instruction, the process proceeds to step 114, and the switching process to the rapid thermal mode is executed. Next, the process proceeds to step 116. At step 116, the corresponding job is retrieved and the document is selected. Note that the job search includes access to a designated PC or server.
Next, at step 117, it is judged whether or not there is a copy start instruction (operation of the start button). If it is judged that there is a copy start instruction, the routine proceeds to step 118, where an initial movement process is performed. In the initial movement process, as described above, the fixing process in the rapid thermal mode is performed.

Next, in step 120, it is determined whether the number of processed sheets has been identified based on the number of read originals G, the number of copies, etc., and if the number of processed sheets has been determined, the process proceeds to step 122.
At step 122, the parameters F1, F2, P1, P2, W1, W2 are fetched. Since these parameters have fixed numerical values (constants) and values which vary depending on the environment (variables), it is preferable to capture them each time the fixing process is performed.

In step 124, the number of processed sheets N is grasped, and then the process proceeds to step 126. In step 126, the arithmetic expression (1) is read.
In step 128, the parameter acquired in step 122 and the number of processed sheets N grasped in step 124 are substituted into the read out equation (1). Then, in step 130, it is determined whether or not the arithmetic expression (1) is established.

  Then, if it is determined in step 130 that the equation (1) is established, processing for maintaining the fast heat mode currently set is performed, and then the process proceeds to step 134. On the other hand, when it is determined that the arithmetic expression (1) is not established, the process of switching to the heat storage mode is performed (step 132), and then the process proceeds to step 134. Then, in step 134, the fixing process to the sheet P is further continued.

FIG. 7 is a diagram showing the process executed at the time of remote printing in step 104 of FIG.
First, at step 150, the parameters F1, F2, P1, P2, W1, W2 are fetched. Next, at step 152, the number of processed sheets N is grasped, and at step 154, the arithmetic expression (1) is read. Next, at step 156, the parameters F1, F2, P1, P2, W1, W2 and the number of processed sheets N obtained at step 150 and step 152 are substituted into the arithmetic expression (1). Then, in step 158, it is determined whether the arithmetic expression (1) is established.

  Then, if it is determined in step 158 that the condition is satisfied, the process proceeds to step 160 to perform switching processing to the rapid thermal mode. On the other hand, when it is determined in step 158 that the condition is not established, the process proceeds to step 162, and a switching process to the heat storage mode is performed. Thereafter, the image forming process on the sheet P is started (step 164).

FIG. 8 is a flow chart showing the flow of processing executed when the job ends.
In addition to the processing executed at the end of the job, FIG. 8 also describes processing at the start of the job executed next to the job. Also, in the following description, two jobs that are temporally adjacent to each other will be described. Of the two jobs, the first job to be performed (a job for explaining the end processing) is referred to as a “preceding job” and The job to be processed (the job that explains the start process) is referred to as "following job". Further, in the following description, the case where the subsequent job is a job for starting the fixing process in the rapid thermal mode will be described.

  In the present embodiment, when the preceding job ends (step 201), it is determined whether the temperature of the temperature-sensitive magnetic member 314 is equal to or higher than a predetermined threshold (predetermined predetermined temperature) (step 202). ). Here, the temperature of the temperature-sensitive magnetic member 314 is grasped by the temperature-sensitive magnetic member thermistor 335 shown in FIG. Note that this determination and each process described below are performed by the control unit 200.

  Here, if it is determined in step 202 that the temperature of the temperature-sensitive magnetic member 314 is lower than a predetermined threshold value, then the temperature-sensitive magnetic member 314 contacts the fixing belt 302 in step 203. Determine if it is. Then, when the temperature-sensitive magnetic member 314 is in contact with the fixing belt 302, the temperature-sensitive magnetic member 314 is separated from the fixing belt 302 (step 204). Then, in step 205, it is determined whether or not there is a subsequent job (a job to be started in the rapid thermal mode). If there is no subsequent job, the process is ended.

  On the other hand, if it is determined in step 205 that there is a subsequent job (job to be started in the rapid thermal mode), the process proceeds to step 210. In this step 210, the job is started in the rapid thermal mode. In addition, in the state where the temperature sensitive magnetic member 314 is separated from the fixing belt 302, this subsequent job is started.

Next, a process when it is determined in step 202 that the temperature of the temperature-sensitive magnetic member 314 is equal to or higher than a predetermined threshold value will be described.
When it is determined in step 202 that the temperature of the temperature-sensitive magnetic member 314 is equal to or higher than a predetermined threshold value, in step 206, the fixing device 64 is in any of the fast heat mode and the heat storage mode. Determine if it is. In addition, it is determined whether the preceding job has ended in the fixing mode such as the fast heat mode or the heat storage mode.

When it is determined in step 206 that the state of the fixing device 64 is in the rapid thermal mode, the temperature-sensitive magnetic member 314 is brought into contact with the fixing belt 302 (step 207).
On the other hand, if it is determined in step 206 that the state of the fixing device 64 is in the heat storage mode, the state is maintained.

Next, in step 208, as in the case of step 205, it is determined whether there is a subsequent job (a job to be started in the rapid thermal mode). Then, if it is determined in step 208 that there is no subsequent job, the process returns to step 202, and the processes after step 202 are executed again.
On the other hand, if it is determined in step 208 that there is a subsequent job, the process proceeds to step 209. At step 209, the temperature sensitive magnetic member 314 is separated from the fixing belt 302. Next, in step 210, the subsequent job is started in the rapid thermal mode. In addition, the following job is started in a state where the temperature sensitive magnetic member 314 is separated from the fixing belt 302.

  Here, although the case where the succeeding job is a job for starting the fixing process in the rapid thermal mode has been described as an example, the succeeding job is a job for starting the fixing process in the heat storage mode. The temperature sensitive magnetic member 314 is brought into contact with the fixing belt 302 at the time of reception. Alternatively, when the temperature-sensitive magnetic member 314 is in contact with the fixing belt 302 at the time of receiving the subsequent job, the contact state is maintained.

FIG. 9 is a diagram showing the temperature of the fixing belt 302 when the process shown in FIG. 8 is performed.
The temperature curve indicated by reference numeral 9A in FIG. 9 indicates the temperature of the fixing belt 302 when the processes of steps 202, 206, 208, 209, and 210 of FIG. 9 are performed.
More specifically, the temperature sensitive magnetic member 314 in a state in which the temperature is higher than the threshold is brought into contact with the fixing belt 302 until the subsequent job is started (until the subsequent job is received by the image forming apparatus 10). 18 shows a temperature curve when the temperature-sensitive magnetic member 314 is separated from the fixing belt 302 at the time of reception of a subsequent job (at the time of start).

In the process when the temperature curve indicated by reference numeral 9A is obtained, the temperature sensitive magnetic member 314 having a large heat capacity and still having heat is in contact with the fixing belt 302 until the subsequent job is started. Therefore, the fixing belt 302 is difficult to cool.
In this case, the temperature of the fixing belt 302 is high at the start of the subsequent job, whereby the fixing belt 302 reaches a predetermined fixing temperature in a shorter time.

In the present embodiment, separation of the temperature-sensitive magnetic member 314 from the fixing belt 302 (movement of the temperature-sensitive magnetic member 314) is performed in a section indicated by reference numeral 9D in FIG.
This section (hereinafter referred to as “separating section 9D”) is a section in which the temperature sensitive magnetic member 314 is still in contact with the fixing belt 302, and the temperature sensitive magnetic member 314 is not heated. Heats the fixing belt 302 in contact. For this reason, the slope of the temperature rise is reduced in the separated section 9D.
In addition, in the present embodiment, when the subsequent job is received, the heating of the fixing belt 302 is started. At this time, in the separated section 9D, part of the heat of the fixing belt 302 escapes to the temperature-sensitive magnetic member 314 and the temperature The slope of the rise is reduced.

  The temperature curve indicated by reference numeral 9B in FIG. 9 indicates the temperature of the fixing belt 302 in the first comparative example. More specifically, the temperature of the fixing belt 302 when the temperature-sensitive magnetic member 314 is not in contact with the fixing belt 302 is shown.

In the first comparative example, since the temperature-sensitive magnetic member 314 is not in contact with the fixing belt 302, the heat radiation from the fixing belt 302 having a small heat capacity proceeds. For this reason, in the section indicated by reference numeral 9E in the drawing (hereinafter, referred to as "heat release section 9E"), the slope of the temperature decrease is large, and the temperature of the fixing belt 302 decreases to room temperature.
Thereafter, when the subsequent job is received, the fixing belt 302 is heated. As a result, the temperature of the fixing belt 302 rises, and the temperature of the fixing belt 302 reaches a predetermined fixing temperature.
In the first comparative example, the temperature of the fixing belt 302 is room temperature when the subsequent job is received. Therefore, it takes more time to reach the fixing temperature (compared to the case where the temperature curve indicated by reference numeral 9A is obtained) as compared to the present embodiment.

A temperature curve indicated by reference numeral 9C in FIG. 9 indicates the temperature of the fixing belt 302 in the second comparative example. This temperature curve shows the temperature of the fixing belt 302 when the temperature-sensitive magnetic member 314 is in contact with the fixing belt 302 until the subsequent job is received, regardless of the temperature of the temperature-sensitive magnetic member 314.
In addition, even when the temperature of the temperature-sensitive magnetic member 314 falls below a predetermined threshold value, the temperature-sensitive magnetic member 314 is brought into contact with the fixing belt 302 until the subsequent job is received. Indicates the temperature.

In the temperature curve shown by the code 9C, the temperature sensitive magnetic member 314 is brought into contact with the fixing belt 302 until the subsequent job is received, so that the fixing belt 302 is hard to cool like the temperature curve shown by the code 9A. Compared to the temperature curve shown in, the decrease in temperature is gradual.
On the other hand, in the second comparative example, the time for reaching the fixing temperature (indicated as "t3" in the figure) is longer than in the example and the first comparative example. In addition, the warm-up time is the longest.

Here, in the second comparative example, the temperature of the temperature-sensitive magnetic member 314 is smaller than the threshold when receiving the subsequent job. In this case, even if heating of the fixing belt 302 is started, the heat of the fixing belt 302 is taken away by the temperature-sensitive magnetic member 314 in a cooled state.
As a result, in the separated section 9D in which the temperature sensitive magnetic member 314 is in contact with the fixing belt 302, the temperature rise of the fixing belt 302 is suppressed. Then, when the separation section 9D ends, the temperature rise starts.

  In the second comparative example, since the temperature rise is suppressed in the separation section 9D, the warm-up time is longer than in the first comparative example. In the first comparative example, although the temperature of the fixing belt 302 is lowered to room temperature, the temperature of the fixing belt 302 rises in the separated section 9D, so the warm-up time is shorter than that of the second comparative example.

When the temperature-sensitive magnetic member 314 is brought into contact with the fixing belt 302, the heat radiation of the fixing belt 302 is suppressed, and basically the warm-up time is shortened.
However, if the temperature of the temperature-sensitive magnetic member 314 is lowered too much, the heat of the fixing belt 302 will be taken reversely at the time of heating, and the warm-up time will be longer than in the embodiment where the temperature-sensitive magnetic member 314 is not in contact at all. Sometimes.
For this reason, in the present embodiment, when the temperature of the temperature-sensitive magnetic member 314 falls below a predetermined temperature, the temperature-sensitive magnetic member 314 is separated from the fixing belt 302.

  In the above description, the temperature of the temperature-sensitive magnetic member 314 is measured, and the separation of the temperature-sensitive magnetic member 314 from the fixing belt 302 is performed depending on whether the temperature of the temperature-sensitive magnetic member 314 exceeds a predetermined threshold. Although the presence or absence is determined, whether or not to perform this separation may be determined based on information other than the temperature of the temperature-sensitive magnetic member 314. For example, based on the temperature of the fixing belt 302, it may be determined whether or not separation is performed.

Further, for example, based on the number of sheets P subjected to the fixing process by the fixing device 64 (based on the number of sheets P subjected to the fixing process in the preceding job), it may be determined whether separation is performed. .
More specifically, when the number of sheets of paper P subjected to the fixing process is large, the heat of the temperature-sensitive magnetic member 314 is taken away by the sheet P, and the temperature decrease of the temperature-sensitive magnetic member 314 is accelerated. The temperature sensitive magnetic member 314 is separated from the fixing belt 302.
On the other hand, when the number of sheets P subjected to the fixing process is small, the temperature drop of the temperature-sensitive magnetic member 314 is suppressed, so that the fixing belt 302 starts at a later timing than when the number of sheets P is large. The temperature sensitive magnetic member 314 is separated.

  Further, for example, it may be determined whether or not separation is to be performed based on an elapsed time from the end of energization of the exciting coil 310 (see FIG. 2). More specifically, when the elapsed time is long, the temperature of the temperature-sensitive magnetic member 314 decreases, so the temperature-sensitive magnetic member 314 is separated from the fixing belt 302 earlier. On the other hand, when the elapsed time is short, the temperature sensitive magnetic member 314 is separated from the fixing belt 302 at a late timing.

Furthermore, even if the threshold described above is set according to the temperature (environmental temperature) of the portion where the image forming apparatus 10 is installed (in-machine temperature of the image forming apparatus 10 or external temperature of the image forming apparatus 10). Good. In addition, the threshold may be changed in accordance with the temperature (environmental temperature) of the place where the image forming apparatus 10 is installed. The setting (changing) of the threshold is performed by the control unit 200 that functions as setting means.
Further, the threshold may be set in accordance with the value of the power supply voltage supplied to the image forming apparatus 10. In other words, the threshold may be changed in accordance with the value of the power supply voltage supplied to the image forming apparatus 10.

  Further, in the present embodiment, when the print job is received, the separation control is performed. However, the control is not performed according to the conditions. For example, when the temperature of the member to be heated is higher than the fixing temperature (ready temperature) (a predetermined temperature higher than the above-mentioned predetermined threshold), the warm-up is short even if the heating is continued. . Therefore, by performing control not to separate, it is possible to shorten the heating time for the separated part.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 64 Fixing device 66 Advancing and moving mechanism 200 Control part 240 Image forming part 302 Fixing belt 310 Excitation coil 314 Temperature sensitive magnetic member 334 Thermistor for belt 335: Thermistor for temperature sensitive magnetic members

Claims (7)

A fixing member for fixing an image on a recording material to the recording material;
A heated member disposed to face the fixing member and configured of a temperature-sensitive magnetic member ;
Heating means for electromagnetically heating the fixing member and the heated member;
Contact / separation means for moving the heated member away from and in contact with the fixing member;
The temperature of the fixing member and the member to be heated and our Keru the heated member after the fixing operation was performed is finished according to the printing job in contact are predetermined with respect to the temperature of the heated member itself for more than a first temperature, without the separation between the heated member and the fixing member, when the member to be heated is lower than the first temperature, it is separated the heated member from the fixing member And control means for separating the heated member from the fixing member when the heated member is in contact with the fixing member when a new print job is received .
Have
In the case where the temperature of the heated member that has exceeded the first temperature becomes lower than the first temperature after the fixing operation is completed and the new print job is received. The heating member is separated from the fixing member without waiting for the reception of the new print job, and when the new print job is received, the heating member is already separated from the fixing member. apparatus. A fixing member for fixing an image on a recording material to the recording material;
A heated member disposed to face the fixing member and configured of a temperature-sensitive magnetic member ;
Heating means for electromagnetically heating the fixing member and the heated member;
Contact / separation means for moving the heated member away from and in contact with the fixing member;
In the case where the temperature of the heat-receiving member is equal to or higher than the first predetermined temperature after the fixing operation performed according to the print job is completed in a state where the fixing member and the heat-receiving member are in contact, Control means for maintaining the contact state between the fixing member and the fixing member, and controlling the contact / separation unit to separate the heating member from the fixing member when the heating member is less than the first predetermined temperature When,
Have
When the heated member and the fixing member are in contact with each other when a new print job is received, the control member separates the heated member from the fixing member, and the heated member is the heated member. A fixing device that performs heating by the heating unit in a state of being separated from the fixing member . A fixing member for fixing an image on a recording material to the recording material;
A heated member disposed to face the fixing member and configured of a temperature-sensitive magnetic member ;
Heating means for electromagnetically heating the fixing member and the heated member;
Contact / separation means for moving the heated member away from and in contact with the fixing member;
In the case where the temperature of the heated member is equal to or higher than the first predetermined temperature after the fixing operation performed according to the print job is finished in a state where the fixing member and the heated member are separated , the heated member and brought into contact with the said fixing member, control the heated member is configured to control the moving means so that if it is less than the first predetermined temperature maintaining the state in which the heated member is separated from the fixing member Means,
Have
When the heated member and the fixing member are in contact with each other when a new print job is received, the control member separates the heated member from the fixing member, and the heated member is the heated member. A fixing device that performs heating by the heating unit in a state of being separated from the fixing member . The fixing device according to any one of claims 1 to 3, further comprising a heated member temperature detection unit that detects a temperature of the heated member . The fixing device according to any one of claims 1 to 4 , further comprising a fixing member temperature detection unit that detects a temperature of the fixing member . A fixing member for fixing an image on a recording material to the recording material;
A heated member disposed to face the fixing member and configured of a temperature-sensitive magnetic member ;
Heating means for electromagnetically heating the fixing member and the heated member;
Contact / separation means for moving the heated member away from and in contact with the fixing member;
In the case where the temperature of the heat-receiving member is equal to or higher than the first predetermined temperature after the fixing operation performed according to the print job is completed in a state where the fixing member and the heat-receiving member are in contact, Control means for maintaining the contact state between the fixing member and the fixing member, and controlling the contact / separation unit to separate the heating member from the fixing member when the heating member is less than the first predetermined temperature When,
Have
The control means is configured to contact the heated member and the fixing member when a new print job is received, and the temperature of the heated member is higher than the first predetermined temperature. less than in the case, the the member to be heated is separated from the fixing member, when the temperature of the member to be heated is equal to or greater than the second predetermined temperature, the fixing device is not the member to be heated is separated from the fixing member. Image forming means for forming an image on a recording material;
A fixing member for fixing an image formed on a recording material by the image forming means to the recording material;
A heated member disposed to face the fixing member and configured of a temperature-sensitive magnetic member ;
Heating means for electromagnetically heating the fixing member and the heated member;
Contact / separation means for moving the heated member away from and in contact with the fixing member;
After the fixing operation performed according to the print job is completed in a state where the fixing member and the member to be heated are in contact , if the temperature of the member to be heated is equal to or higher than a predetermined temperature, the member to be heated and the fixing Control means for maintaining the state of contact with the member, and controlling the contact / separation means to separate the heated member from the fixing member when the heated member is less than a predetermined temperature;
Have
When the heated member and the fixing member are in contact with each other when a new print job is received, the control member separates the heated member from the fixing member, and the heated member is the heated member. The image forming apparatus performs heating by the heating unit in a state of being separated from the fixing member .

Images