JP2018116113A - Fixation device and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixation device in which the power consumption at the time of the fixation operation is reduced by making the heat in a storage body of the fixation device hardly conducted to the outside of the storage body.SOLUTION: A fixation device 60 includes: a heating body 61 which heats a medium S formed with a toner image; a heat source 63 which applies the heat to the heating body 61; a pressure body 62 which forms a nip N with the heating body 61 and pressurizes the medium S conveyed and passing through the nip N; a heating body 61; a storage body HG being the storage body HG which stores the heat source 63 and the pressure body 62 and is formed with an opening HG1 through which the medium S can pass; a lid 68 which opens/closes the opening HG1; an opening/closing mechanism 69 which opens/closes the opening HG1 with the lid 68; and a control unit being the control unit which controls the heat source 63 and the opening/closing mechanism 69 and causes the opening/closing mechanism 69 to move the lid 68 for closing the opening HG1 at the time of application of the heat to the heating body 61 by the heat source 63 and at the time of stand-by being the non-passage time of the medium S through the nip N.SELECTED DRAWING: Figure 5A

Description

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

  For example, Patent Document 1 discloses a fixing device that fixes a toner image on a recording medium while conveying the recording medium through a nip portion between a heating member and a pressure member. In this fixing device, an opening through which a recording medium can pass is formed in a housing that accommodates a heating member and a pressure member.

JP 2004-271760 A

  By the way, in the case of the fixing device described above, the heat applied to the heating member by the heat source for performing the fixing operation is conducted from the opening to the outside of the casing (that is, outside the fixing device). As a result, in the case of the above fixing device, the heat conducted from the opening to the outside of the casing is wasted without being used for the fixing operation.

  An object of the present invention is to provide a fixing device in which power consumption during fixing operation is reduced by making it difficult for heat inside the container of the fixing device to be conducted outside the container.

  The first fixing device of the present invention is configured to rotate around a heating body that heats the medium on which the toner image is formed while rotating, and a heat source that applies heat to the heating body by which the heating body heats the medium. A heating body that forms a nip with the heating body, pressurizes the medium that is conveyed and passes through the nip, and a housing body that houses the heating body, the heat source, and the pressing body, the nip A container in which an opening through which a medium can pass is formed on the upstream side of the medium in the conveyance direction, a lid that opens and closes the opening, an opening and closing mechanism that moves the lid and opens and closes the opening by the lid; A control unit for controlling the heat source and the opening / closing mechanism, wherein the lid is moved by the opening / closing mechanism during standby when the heat source applies heat to the heating body and when the medium does not pass through the nip. Control to close the opening It has a, and.

  The second fixing device of the present invention further has a function of guiding the conveyed medium to the nip when the lid is moved by the opening / closing mechanism when the medium passes through the nip and the opening is opened. Have

  In the third fixing device of the present invention, the pressing body is further moved by the opening / closing mechanism to a first position where the nip is formed with the heating body and a second position separated from the heating body. The opening / closing mechanism moves the pressure member from the first position to the second position when the lid is moved to close the opening, and moves the lid to open the opening when the opening is opened. The pressing body is moved from the second position to the first position.

  In the fourth fixing device of the present invention, the waiting time is a ready time from when the control unit receives data for performing a fixing operation accompanying an image forming operation until the medium reaches the opening. ing.

  In the fifth fixing device of the present invention, the standby state is a sleep mode from the end of the fixing operation until the medium reaches the opening during the next fixing operation.

  In the sixth fixing device of the present invention, the standby time is a preparation time from when the power is turned on until the fixing operation is possible.

  The image forming apparatus of the present invention includes a forming unit that forms a toner image on a medium and the fixing device, and the medium on which the toner image is formed by the forming unit is heated and pressed to fix the toner image on the medium. A fixing device.

  The fixing device of the present invention reduces power consumption during the fixing operation by making it difficult for heat inside the housing of the fixing device to be conducted outside the housing.

1 is a perspective view of an image forming apparatus according to an exemplary embodiment. 1 is a schematic view (cross-sectional view) of an image forming apparatus according to an embodiment as viewed from the front side. FIG. 2 is a block diagram illustrating a relationship between a control unit configuring the image forming apparatus of the present embodiment and each unit configuring the image forming apparatus. FIG. 3 is a schematic diagram (longitudinal sectional view) showing a fixing device constituting the image forming apparatus of the present embodiment as viewed from the front side, and showing a state where the lid is opened (a state when the medium passes). FIG. 4B is a perspective view of a part of the cam mechanism in FIG. 4A. FIG. 6 is a schematic view (longitudinal sectional view) showing the fixing device of the present embodiment as viewed from the front side, and showing a state where the lid closes the opening (standby state). It is a one part perspective view of the cam mechanism in FIG. 5A. It is a flowchart of the fixing operation of this embodiment. It is a flowchart of the fixing operation of a 1st modification. It is a flowchart of the fixing operation of a 2nd modification.

<Overview>
Hereinafter, the entire configuration of the image forming apparatus 10 (see FIGS. 1 and 2) and the image forming operation by the image forming apparatus 10, and the fixing device 60 (see FIGS. 4A and 5A), which is the main part of the present embodiment. The configuration and the operation of the fixing device 60, and the effects and modifications of the present embodiment will be described in the order of description.

  In the present specification, the directions indicated by arrows Fr and Rr in the figure are the front and back sides of the apparatus depth direction, respectively, the directions indicated by arrows R and L are the right and left sides of the apparatus width direction, arrows U and arrows Lo, respectively. The directions shown are the upper side and the lower side of the apparatus height direction, respectively. Further, in this specification, the side of the image forming apparatus 10 viewed from the front side in the apparatus depth direction is described as the front side of the image forming apparatus 10.

<Overall configuration of image forming apparatus>
The overall configuration of the image forming apparatus 10 of this embodiment will be described with reference to FIGS. 1 and 2. As shown in FIG. 2, the image forming apparatus 10 includes a main body 20, a fan FN, a paper feed cassette 30, a transport device 40, a toner image forming unit 50, a fixing device 60, and a control unit CU. It is an electrophotographic apparatus that is configured to include.

  The main body 20 has a function of accommodating a paper feed cassette 30, a transport device 40, a toner image forming unit 50, a fixing device 60, and a control unit CU therein. The main body 20 is a box-shaped exterior. A part of the upper surface of the main body 20 is a discharge tray 22 from which the medium S on which the toner image is fixed (image is formed) is discharged. Note that a lid 24 is provided on the left end surface of the main body 20 as viewed from the front side, and the fixing device 60 described later can be attached to and detached from the main body 20 in a state where the lid 24 is tilted (see FIG. 1). Has been. Further, a fan FN for discharging the air in the main body 20 to the outside is attached to the right side of the main body 20 (upstream side in the conveyance direction of the medium S with respect to the fixing device 60) when viewed from the front side.

  The paper feed cassette 30 is arranged on the lower side of the main body 20 and accommodates the medium S on which an image is formed in an overlapping manner. The transport device 40 has a function of transporting the medium S stored in the paper feed cassette 30 along the transport path P from the paper feed cassette 30 to the discharge tray 22. The conveying device 40 includes a plurality of driven rollers and driving rollers, and a driving source (not shown) that drives the plurality of driving rollers. Here, the direction indicated by the arrow Y in the figure is the transport direction of the medium S.

  The toner image forming unit 50 has a function of forming a toner image on the medium S conveyed by the conveying device 40. The toner image forming unit 50 is disposed in the center of the main body 20 when viewed from the front side. The toner image forming unit 50 includes a photoconductor 51, a charging device 52, an exposure device 53, a developing device 54, and a transfer roller 55.

  The toner image forming unit 50 charges the photoconductor 51 rotating around the axis by the charging device 52, exposes the photoconductor 51 by the exposure device 53 to form a latent image, and forms the latent image as a toner image by the developing device 54. The toner image is developed and the toner image is transferred to the medium S by the transfer roller 55. As described above, the toner image forming unit 50 forms a toner image on the medium S.

  The fixing device 60 has a function of fixing the toner image on the medium S (the medium on which the toner image is formed) on which the toner image is transferred by the toner image forming unit 50. The fixing device 60 is disposed on the left side in the main body 20 when viewed from the front side. Since the fixing device 60 is a main part of the present embodiment, a specific configuration of the fixing device 60 will be described later.

  The control unit CU has a function of receiving image data from an external device (not shown) and controlling each unit constituting the image forming apparatus 10 based on the image data. The control unit CU controls, for example, a heat source 63 and a cam mechanism 69 of a fixing device 60 (see FIGS. 4A and 5A) described later, and applies heat to the heating roller 61 by the heat source 63 and a nip N of the medium S. When the camera is in a non-passing state, the cam mechanism 69 moves the lid 68 to close the opening HG1. Here, the standby time means a ready time from when the control unit CU receives data for performing a fixing operation accompanying the image forming operation until the medium S reaches the opening HG1. Other specific functions in the control unit CU will be described in the description of the image forming operation and the operation of the fixing device 60 described later.

<Image forming operation>
Next, an image forming operation by the image forming apparatus 10 of the present embodiment will be described with reference to FIGS.

  First, the control unit CU that has received image data from an external device (not shown) operates the toner image forming unit 50. Specifically, the control unit CU sends a remote signal for forming a toner image to the toner image forming unit 50 (see FIG. 3). As a result, the charging device 52 charges the photoconductor 51, the exposure device 53 exposes the photoconductor 51 to form a latent image, and the developing device 54 develops the latent image as a toner image. A toner image is formed.

  In addition, the control unit CU sends a remote signal for transporting the medium S to the transport device 40. Then, the conveying device 40 adjusts the timing at which the toner image formed on the photoconductor 51 reaches the transfer position (the portion where the photoconductor 51 and the transfer roller 55 are in contact) by the rotation around the axis of the photoconductor 51. The medium S is sent to the transfer position. As a result, the transfer roller 55 transfers the toner image formed on the photoconductor 51 to the medium S, and a toner image is formed on the medium S.

  Next, the control unit CU sends a remote signal for fixing the toner image on the medium S to the fixing device 60. Then, the fixing device 60 fixes the toner image transferred onto the medium S by the transfer roller 55 on the medium S. As a result, the medium S on which the toner image is fixed, that is, the medium S on which the image is formed is discharged to the discharge tray 22 of the main body 20 further downstream in the transport direction by the transport device 40, and the image forming operation is performed. finish.

<Configuration of main part (fixing device)>
Next, the configuration of the fixing device 60, which is a main part of the present embodiment, will be described in detail with reference to FIGS.

  The fixing device 60 includes a housing HG (an example of a container), a heating roller 61 (an example of a heating body), a pressure roller 62 (an example of a pressure body), a heat source 63, a temperature sensor 66, and a lid 68. And a cam mechanism 69 (an example of an opening / closing mechanism) and a pair of side plates (not shown). The heating roller 61, the pressure roller 62, and the heat source 63 are each long, and are positioned on the pair of side plates in a state in which their longitudinal directions are aligned with each other (in the apparatus depth direction). The fixing device 60 is long, and is attached to the main body 20 of the image forming apparatus 10 with the longitudinal direction thereof aligned with the apparatus depth direction (see FIG. 1).

〔housing〕
As shown in FIGS. 4A and 5A, the housing HG has a function of housing the heating roller 61, the pressure roller 62, the heat source 63, and the temperature sensor 66. In addition, openings HG1 and HG2 through which the medium S transported by the transport device 40 can pass are formed in the right and left portions of the housing HG as viewed from the front side. The opening HG1 is an opening on the upstream side in the transport direction of the medium S with respect to the nip N, which will be described later, and the opening HG2 is an opening on the downstream side in the transport direction of the medium S with respect to the nip N. Further, the housing HG has a stopper HG3 for positioning the lid 68 when a lid 68 described later is moved by the cam mechanism 69 so that the lid 68 opens the opening HG1.

[Heating roller]
The heating roller 61 has a function of heating the toner image (the toner constituting the toner image) formed on the medium S by the toner image forming unit 50 and the medium S. The heating roller 61 is a roller that includes a long pipe 61A and an elastic layer 61B that covers the outer periphery of the pipe 61A.

  The heating roller 61 is driven by a driving source (not shown) while being heated by a heat source 63 described later, and circulates around an axis. Here, the arrow A in FIG. 4A and FIG. 5A indicates the rotating direction of the heating roller 61. The heating roller 61 presses the medium S on which the toner image conveyed by the conveying device 40 is formed with the pressure roller 62 at a nip N described later. As a result, the heating roller 61 contacts the medium S on which the toner image is formed while rotating (rotating) around the axis, heats the medium S, and passes through the nip N with the pressure roller 62. The toner image is fixed on the medium S by pressurizing S.

  Flange (not shown) is fitted to both ends of the heating roller 61, and the heating roller 61 is bonded and fixed to each flange. And each flange is rotatably supported by a pair of side plate via the shaft (illustration omitted) each fitted.

[Pressure roller]
The pressure roller 62 has a function of pressing the toner image (the toner constituting the medium) formed on the medium S by the toner image forming unit 50 and the medium S with the heating roller 61 while rotating. The pressure roller 62 is a roller composed of a long shaft and an elastic coating layer covering the outer periphery thereof. The pressure roller 62 is disposed on the lower side of the heating roller 61 when viewed from the apparatus depth direction. The above-described nip N means a contact portion between the pressure roller 62 and the heating roller 61 formed by the pressure roller 62 and the heating roller 61. The pressure roller 62 is rotated (rotates) around the axis following the heating roller 61. Here, an arrow B in FIGS. 4A and 5A indicates the rotation direction of the pressure roller 62.

  In addition, the pressure roller 62 is located at a position where the nip N is formed with the heating roller 61 (hereinafter referred to as a first position) by a cam mechanism 69 described later, and a position where the nip N is not formed apart from the heating roller 61. (Hereinafter referred to as the second position). Here, the first position is the position of the pressure roller 62 shown in FIG. 4A. Further, the second position is the position of the pressure roller 62 shown in FIG. 5A.

[Heat source]
The heat source 63 has a function of applying heat to the heating roller 61 so that the heating roller 61 heats the medium S. As an example, the heat source 63 is a rod-shaped (or long-shaped) halogen lamp.

〔Temperature sensor〕
The temperature sensor 66 has a function of detecting the temperature of the heating roller 61. As shown in FIG. 4A and FIG. 5A, the temperature sensor 66 is disposed to face the outer periphery of the heating roller 61 as an example. In addition, the temperature (data regarding temperature) detected by the temperature sensor 66 is transmitted to the control unit CU at a predetermined cycle.

〔lid〕
As shown in FIGS. 4A and 5A, the lid 68 has a function of opening and closing an opening HG1 of the housing HG. The lid 68 has a long plate 68A and a protrusion 68B. The long plate 68A extends along the apparatus depth direction, and one end in the short direction is rotatably attached to the ridge line portion with the lower edge (ridge line portion) of the opening HG1 as an axis. The protrusion 68B protrudes from one end surface of the long plate 68A toward the inside of the housing HG. And the lid | cover 68 is comprised so that it may fall toward the inner side of the housing HG with dead weight. Here, FIG. 4A illustrates a state in which the projection 68B hits the stopper HG3 and the lid 68 opens the opening HG1 with the lid 68 tilted. In the state where the lid 68 is opened with the opening HG1 shown in FIG. 4A, the long plate 68A of the lid 68 is arranged below the transport path P along the transport path P. Yes. 4A, the long plate 68A has a function of guiding the medium S conveyed by the conveying device 40 to the nip N (leading the medium S so as to reach the nip N). FIG. 5A illustrates a state in which the lid 68 is moved by a cam mechanism 69 described later to close the opening HG1. In the present embodiment, the pressure roller 62 is positioned at the first position and the lid 68 is illustrated in FIG. 4B when the lid 68 is disposed at the position illustrated in FIG. 4A by the cam mechanism 69 described later. The pressure roller 62 is configured to be located at the second position in a state where the pressure roller 62 is disposed at the position where the pressure is applied.

[Cam mechanism]
The cam mechanism 69 has a function of moving the lid 68 and opening / closing the opening HG1 by the lid 68 during standby. The cam mechanism 69 moves the lid 68 to close the opening HG1 and moves the pressure roller 62 from the first position (see FIG. 4A) to the second position (see FIG. 5A), and moves the lid 68 to open the opening. When HG1 is opened, it has a function of moving the pressure roller 62 from the second position to the first position. The cam mechanism 69 has a main body 69A and a support portion 69B (see FIGS. 4A and 4B and FIGS. 5A and 5B).

(Body)
The main body 69 </ b> A has a combination 71 of a pair of first cam 72 and second cam 73. The main body 69A transmits the torque from the drive source (not shown), and the first posture (see FIGS. 4A and 4B) in which the posture of the combination 71 is determined, and the first posture of the combination 71 is changed to the first. It has a function of changing to a predetermined second posture (see FIGS. 5A and 5B) different from the posture.

  As shown in FIGS. 4B and 5B, the main body 69A has a pair of first cams 72, a second cam 73, a shaft 74, a shaft 75, a gear group 76, and a large gear 77. ing. Here, the shaft 74 and the shaft 75 are arranged along the apparatus depth direction as shown in FIGS. 4B and 5B. In addition, the shaft 75 is shorter than the shaft 74, and the shaft 74 and the shaft 75 are arranged in a state where their one ends (ends on the front side in the apparatus depth direction) are aligned.

  The pair of first cams 72 has a function of determining the posture of the support rod 80 by hitting a support rod 80 of a support portion 69B described later. The pair of first cams 72 are respectively fixed to both end sides of the shaft 74 as shown in FIGS. 4B and 5B.

  The second cam 73 has a function of determining the posture of the lid 68 while contacting the lid 68 and supporting the lid 68. As shown in FIGS. 4B and 5B, the second cam 73 is fixed to the other end side (the depth side in the apparatus depth direction) of the shaft 75.

  The gear group 76 has a function of transmitting torque transmitted from the driving source (not shown) to the large gear 77 to the shaft 74 and the shaft 75. As shown in FIG. 4B and FIG. 5B, the gear group 76 includes three spur gears as an example. As shown in FIGS. 4B and 5B, two spur gears of the spur gears of the gear group 76 are fixed to one end side of the shaft 74 and the shaft 75, respectively. Further, the spur gears fixed to the shaft 74 and the shaft 75 are in mesh with each other. Further, the remaining one of the spur gears of the gear group 76 and the spur gear fixed to the shaft 74 are in mesh with each other. With the above configuration, when the remaining one spur gear rotates around its axis, the spur gears fixed to the shaft 74 and the shaft 75 also rotate around their respective axes.

  The large gear 77 has a function of transmitting torque transmitted from a drive source (not shown) to the gear group 76. As shown in FIGS. 4B and 5B, the large gear 77 is disposed on the opposite side of the shafts 74 and 75 with the gear group 76 interposed therebetween. The large gear 77 has a configuration in which two spur gears having different diameters in the axial direction are overlapped in the axial direction around the axis. Here, as for the large gear 77 of FIG. 4B and FIG. 5B, only the spur gear with a larger diameter is illustrated among two spur gears with different diameters. The spur gear having the smaller diameter is hidden behind one spur gear constituting the large gear 77 in FIGS. 4B and 5B. The spur gear having the smaller diameter and the spur gear constituting the gear group 76 are hidden. Of these, the remaining one spur gear is in mesh with each other. The gear fixed to the rotation shaft of the drive source (not shown) and the gear having the larger diameter constituting the large gear 77 are in mesh with each other.

  With the above configuration, when the drive source (not shown) rotates around the axis, the large gear 77 rotates around the axis, and each spur gear of the gear group 76 rotates around each axis as the large gear 77 rotates. The shafts 74 and 75 are also rotated around their respective axes. Accordingly, the pair of first cams 72 fixed to the shaft 74 and the second cam 73 fixed to the shaft 75 rotate around the axes of the shafts 74 and 75, respectively. (Posture) is changed. The combination 71 of the pair of first cams 72 and the second cams 73 shown in FIGS. 4A and 4B has the above-described first posture, and the pair of first cams shown in FIGS. 5A and 5B. The combination 71 of the 1 cam 72 and the 2nd cam 73 is made into the above-mentioned 2nd attitude | position.

(Support part)
The support part 69B has a function of rotatably supporting the pressure roller 62. The support portion 69B includes a pair of support rods 80, a pair of support shafts 82, and a pair of coil springs (not shown). Each support shaft 82 is disposed on the left side of the pressure roller 62 when viewed from the front side, and is fixed to each side plate (not shown). Each support rod 80 has a through hole formed at one end in the longitudinal direction and at the center in the longitudinal direction. Each support shaft 82 is rotatably fitted in a through hole on one end side in the longitudinal direction of each support rod 80, and a shaft serving as a rotation shaft of the pressure roller 62 is fitted in a through hole in the center in the longitudinal direction. Yes. Each coil spring (not shown) urges each support rod 80 in the clockwise direction when viewed from the front side. Each support rod 80 is supported from the lower side by each first cam 72 while being biased from the upper side by each coil spring with each support shaft 82 as the center of rotation, and its posture is determined.

(Relationship between cam mechanism and support)
As described above, the main body 69A and the support portion 69B have been described separately. However, when the combination 71 is changed from the second posture to the first posture by the cam mechanism 69, the lid 68 is in a state in which the opening HG1 is opened and supported. The pressure roller 62 supported by the portion 69B is moved from the second position to the first position to form a nip N with the heating roller 61. On the other hand, when the combination 71 is changed from the first posture to the second posture by the cam mechanism 69, the lid 68 is in a state in which the opening HG1 is closed and the pressure roller 62 supported by the support portion 69B is provided. It moves from the first position to the second position and is separated from the heating roller 61.

<Operation of fixing device>
Next, the operation of the fixing device 60 of this embodiment (the fixing operation and the opening / closing operation of the lid 68 associated therewith) will be described with reference to FIGS. 3, 4A and 4B, 5A and 5B, and FIG. This will be described with reference to FIGS. 5A and 6). Note that the opening HG1 is closed as shown in FIG. 5A during the period other than the lid 68 of the fixing device 60 of this embodiment and the image forming operation. That is, in the fixing device 60 of the present embodiment, the period from the end of the fixing operation to the time when the medium S reaches the opening HG1 during the next fixing operation (hereinafter referred to as the sleep mode) is the same as in the ready mode. The lid 68 closes the opening HG1.

  Receiving the image data from the external device (not shown), the control unit CU sends a remote signal to the fixing device 60 (see FIG. 3). And the control part CU applies a voltage to the power supply of the heat source 63, and starts provision of the heat | fever to the heating roller 61 by the heat source 63 (refer step S10 of FIG.3 and FIG.6). Further, the control unit CU drives a drive source (not shown) of the heating roller 61 to rotate the heating roller 61 in the direction of arrow A (see step S20 in FIGS. 3 and 6). Along with this, the pressure roller 62 is driven by the heating roller 61 and rotates in the direction of arrow B (see FIG. 5A).

  Next, in accordance with the timing at which the heating roller 61 of the fixing device 60 reaches a predetermined heating temperature, the medium S on which the toner image is formed by the toner image forming unit 50 is transported by the transport device 40 in the transport direction (arrow Y direction). Along the nip N of the fixing device 60 (see FIG. 2). Specifically, the control unit CU determines the timing based on the temperature information of the heating roller 61 sent from the temperature sensor 66. Further, the control unit CU determines whether the medium S on which the toner image is formed has reached before the opening HG1 (see determination step S30 in FIG. 6). As a result, when an affirmative determination is made in determination step S30, the control unit CU drives the drive source of the cam mechanism 69 to move the lid 68 to open the opening HG1 (FIGS. 4A, 4B, and 6). Step S40). Accordingly, the pressure roller 62 moves from the second position (see FIG. 4A) to the first position (see FIG. 5A) to form a nip N with the heating roller 61. Note that the control unit CU repeats the determination step S30 until an affirmative determination is made (see NO in step S30 in FIG. 6).

  Next, the control unit CU determines whether all the media S that are scheduled for image formation (printing targets) have passed through the nip N based on the image data (determination step S50 in FIG. 6). As a result, when an affirmative determination is made in determination step S50, the control unit CU drives the drive source of the cam mechanism 69 again and moves the lid 68 to close the opening HG1 (FIGS. 5A and 5B and FIG. 6 step S60). Accordingly, the pressure roller 62 moves from the first position (see FIG. 5A) to the second position (see FIG. 4A) and is separated from the heating roller 61. The control unit CU repeats the determination step S50 until an affirmative determination is made (see NO in step S60 of FIG. 6).

  Then, the rear end of the last one medium S of the planned image formation target (print target) (or the medium S when the number of the print target medium S is one) passes through the nip N, and When the medium S is discharged from the fixing device 60, the control unit CU stops driving the heating roller 61 and applying a voltage to the heat source 63, and causes the fixing device 60 to end the fixing operation. That is, in the fixing device 60 of the present embodiment, the lid 68 closes the opening HG1 with the end of the fixing operation.

<Effect>
Next, the effect of this embodiment will be described.

<First effect>
For example, in the case of the fixing device disclosed in Patent Document 1, the heat applied to the heating member by the heat source for performing the fixing operation corresponds to the opening of the housing (corresponding to the housing HG) (the opening HG1 serving as the entrance of the medium S) ) From outside the casing (ie outside the fixing device). As a result, in the case of the fixing device described above, the heat conducted from the opening to the outside of the housing is wasted without being used for the fixing operation.

  In contrast, as shown in FIGS. 4A and 5A, the fixing device 60 of the present embodiment includes a lid 68 and a cam mechanism 69, and the control unit CU heats the heating roller 61 by the heat source 63. And the lid 68 is moved by the cam mechanism 69 to close the opening HG1 during the standby state (ready mode and sleep mode) when the medium nip N is not passed.

  Therefore, the fixing device 60 of the present embodiment reduces the power consumption during the fixing operation by making it difficult for the heat in the housing HG to be conducted outside the housing HG (the heat during the ready mode or the sleep mode is reduced). Effective use). Accordingly, the image forming apparatus 10 of the present embodiment reduces the power consumption during image formation by reducing the power consumption during the fixing operation. In the case of the present embodiment, as shown in FIG. 2, a fan FN for discharging the air in the main body 20 to the outside is attached to the upstream side in the conveyance direction of the medium S with respect to the fixing device 60. The above-mentioned effect appears remarkably.

<Second effect>
In the case of this embodiment, the lid 68 not only functions to open and close the opening HG1, but also falls in the housing HG and guides the medium S to be conveyed to the nip N in a state where the opening HG1 is opened. It has a function. Therefore, in the present embodiment, the lid 68 can exhibit functions necessary for the fixing device 60 in any posture.

<Third effect>
In the case of this embodiment, by using the cam mechanism 69, the opening / closing operation of the opening HG1 of the lid 68 and the moving operation of the pressure roller 62 can be performed simultaneously. Therefore, in the case of this embodiment, both operations can be performed with a simple configuration as compared with the case where the opening / closing operation of the opening HG1 of the lid 68 and the movement operation of the pressure roller 62 are operated by different mechanisms. it can.

  As described above, the present embodiment has been described by taking the present embodiment as an example, but the technical scope of the present invention is not limited to the present embodiment. For example, the following forms are also included in the technical scope of the present invention.

  For example, in the description of the present embodiment, the control unit CU has a function of controlling each unit (for example, the fixing device 60) included in the image forming apparatus 10 based on the image data. That is, in the description of this embodiment, the control unit CU is another component of the fixing device 60 in the image forming apparatus 10. However, a portion (function) for controlling the fixing device 60 in the control unit CU may be regarded as a part of the fixing device 60.

  In the description of the present embodiment, the standby time means a ready time from when the control unit CU receives data for performing a fixing operation accompanying the image forming operation until the medium S reaches the opening HG1. . However, as shown in the control flow diagram of the first modified example in FIG. 7A, the power supply of the main body of the image forming apparatus 10 (that is, the power supply of the fixing device 60) is turned on until the fixing operation by the fixing device 60 becomes possible. The time of preparation may be regarded as waiting time, and the opening HG1 may be closed by the lid 68 at the time of preparation. In the case of the first modification, there is an effect that heat at the time of preparation can be effectively used.

  Further, in the description of the present embodiment, it has been described that the lid 68 opens the opening HG1 during the period in which all the media S that are planned image forming targets (printing targets) pass through the nip N. However, as shown in the control flow diagram of the second modified example in FIG. 7B, when the fixing operation is performed on the plurality of media S, the opening HG1 is opened and closed by the lid 68 each time the media S passes through the nip N. You may do it. In the case of the second modification, it is possible to effectively use the heat during the fixing operation as compared with the case of the present embodiment.

10 Image Forming Apparatus 50 Toner Image Forming Unit (Example of Forming Unit)
60 fixing device 61 heating roller (an example of a heating body)
62 Pressure roller (an example of a pressure body)
63 Heat source 68 Lid 69 Cam mechanism (an example of an opening / closing mechanism)
CU control unit HG housing (an example of a container)
HG1 opening N nip S medium

Claims (7)

A heating body for heating the medium on which the toner image is formed while circling;
A heat source for applying heat to the heating body by the heating body to heat the medium;
A pressure body that forms a nip with the heating body while circling, and pressurizes the medium that is conveyed and passes through the nip;
A housing for housing the heating body, the heat source, and the pressurizing body, wherein the housing is formed with an opening through which a medium can pass on the upstream side of the medium in the transport direction of the medium;
A lid for opening and closing the opening;
An opening and closing mechanism for moving the lid and opening and closing the opening by the lid;
A controller for controlling the heat source and the opening / closing mechanism, wherein the lid is moved by the opening / closing mechanism during standby when the heat source applies heat to the heating body and when the medium does not pass through the nip. A controller for closing the opening;
A fixing device provided with The lid has a function of guiding the medium to be conveyed to the nip in a state where the opening is opened by being moved by the opening / closing mechanism when the medium passes through the nip.
The fixing device according to claim 1. The pressure body is movable by the opening / closing mechanism to a first position where the nip is formed with the heating body and a second position spaced apart from the heating body,
The opening / closing mechanism moves the pressure body from the first position to the second position when the lid is moved to close the opening, and moves the lid to open the opening when the lid is moved. Moving from the second position to the first position;
The fixing device according to claim 1. The standby time is a ready time from when the control unit receives data for performing a fixing operation accompanying an image forming operation until the medium reaches the opening.
The fixing device according to claim 1. The standby time is a sleep mode from the end of the fixing operation until the medium reaches the opening during the next fixing operation.
The fixing device according to claim 1. The standby time is a preparation time from when the power is turned on until the fixing operation is possible.
The fixing device according to claim 1. A toner image forming unit for forming a toner image on a medium;
7. The fixing device according to claim 1, wherein the toner image formed on the medium by the toner image forming unit is fixed on the medium.
An image forming apparatus.

Images