JP2019028185A - Heat-fixing device and image forming apparatus including the same - Google Patents

Abstract

To provide a fixing device that eliminates a gap between a stay and a regulation member to control the generation of abnormal noise.SOLUTION: A fixing device comprises: a rotating pressing body; a sleeve-like film that forms a nip part with the pressing body and rotates in association with the pressing body; a regulation member 104 that regulates the locus of the film; and a structure with rigidity that is arranged inside the film and supported by the regulation member, and the fixing device passes a heating target material through the nip part to be heated. The fixing device has at least one member between the structure and regulation member, or the regulation member is elastically deformed.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a fixing device that fixes a toner image on a recording material P, and an image forming apparatus including the same.

  In an electrophotographic image forming apparatus, a process of fixing a toner image onto a sheet through charging, exposure, development, transfer, and fixing steps is generally performed.

  In the fixing process, a fixing method of a roller pair using a fixing roller and a pressure roller has been conventionally used.

  From the viewpoint of energy saving, there is also a fixing film type fixing device in which the fixing roller is made of a thin metal film and the heat capacity is reduced to realize standby-less.

  The fixing device of the fixing film system is a system in which a pressure member fixedly supported inside the fixing film is provided, and the fixing film and the member to be fixed are sandwiched and conveyed between the pressure member and the elastic pressure roller to be fixed. is there.

  As disclosed in Japanese Patent Application Laid-Open No. H10-230, there is a fixing device that includes a regulating member that regulates the orbit of the fixing film and a metal stay provided on the inner surface of the fixing film to maintain strength. The end of the stay is supported by being engaged with a regulating member.

JP 2012-8377 A

  In the fixing device disclosed in Patent Document 1, when the stay and the regulating member are engaged, there is a gap between the stay and the regulating member, and the stay has a backlash. Due to this play, self-excited vibration called stick-slip occurs on the inner surface of the fixing film and the sliding surface of the heating member. There is a problem that a large abnormal noise is caused by the deterioration of the self-excited vibration.

  Here, stick-slip will be described using the one-mass system vibration model of FIG. The mass body in FIG. 1 is an object that vibrates while in contact with a mating member. When the mating member is moving at a constant speed U, the mass body generates friction with the mating member, and therefore moves with the displacement x. At this time, when the slidability between the mass body and the mating member is poor, a sticking state (stick state) and a sliding state (slip state) occur on the ground contact surface. This vibration in which the stick state and the slip state are repeatedly generated is called stick-slip.

  Next, stick slip on the inner surface of the fixing film and the sliding surface of the heating member will be described. A lubricant is interposed between the inner surface of the fixing film and the sliding surface of the heating member in order to improve the slidability. However, since the lubricant is exposed to a high temperature by sliding for a long time and is slid in a state where the viscosity of the lubricant is lowered, the lubricant gradually flows out from the nip between the fixing film and the heating member to the outside of the nip. To go. As a result, the slidability between the inner surface sliding layer of the fixing film and the heating member is deteriorated, and eventually a stick slip that repeats a stick state and a slip state is generated, thereby causing self-excited vibration. When it gets worse, a big noise is generated.

  FIG. 2 shows the result of measuring the time transition of the speed in the direction of conveying the sheet of the fixing film at the time of (a) normal and (b) occurrence of stick slip with a digital laser Doppler meter. The speed of the fixing film was set to 50 mm / s. At normal times, the speed of the fixing film is stable at around 50 mm / s as shown in FIG. 2A, but when squealing occurs, zero and 50 mm / s are set as shown in FIG. 2B. It can be confirmed that the speed is oscillating within a large range. Here, the state where the speed is zero is a stick state, and the state where the speed greatly increases from the zero speed indicates a slip state.

  Accordingly, an object of the present invention is to provide a fixing device that eliminates the gap between the stay and the regulating member and suppresses the generation of the above-described abnormal noise.

In order to achieve the above object, a fixing device according to the present invention includes:
A pressure member that rotates, a sleeve-like film that forms a nip portion with the pressure member and rotates with the pressure member, a regulating member that regulates the trajectory of the film, and is disposed inside the film, A fixing device having a rigid structure supported by the regulating member, and heating the heated material through the nip portion;
It has at least one member between the structure and the restricting member, or the restricting member is elastically deformed.

  According to the fixing device of the present invention, it is possible to suppress noise generated when stick slip deteriorates by eliminating the gap between the stay and the regulating member.

Diagram explaining stick-slip of one-degree-of-freedom system model The figure explaining the speed in the direction which conveys the paper of a fixing film at the time of stick slip occurrence Main cross section of image forming device Side view of fixing device Cross section of fixing device The perspective view explaining engagement of a control member and a stay Restriction member front view for explaining engagement between the restriction member and the stay The figure explaining engagement of the regulating member and stay in Example 1 Diagram for explaining the length Y ₁ between the length X ₁ and the stay end between the engagement hole of the regulating member in Embodiment 2 Diagram for explaining the length Y ₂ between the length X ₂ and the stay end between the engagement hole of the regulating member in Embodiment 2 The figure explaining engagement of the regulating member and stay in Example 3 Diagram for explaining the length Y ₃ between the length X ₃ and the stay end between claw portion in Embodiment 3 The figure explaining engagement of a nail | claw part and a stay in the nail | claw catching part in Example 3. The figure explaining engagement of the regulating member and stay in Example 4

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. It is not intended to limit the scope to the following embodiments.

[Configuration of Image Forming Apparatus]
FIG. 3 is a cross-sectional view of a color electrophotographic printer which is an example of the image forming apparatus of the present embodiment, and is a cross-sectional view orthogonal to the conveyance direction of the recording material P.

In this embodiment, the color electrophotographic printer is simply referred to as “printer”. The recording material P is for forming a toner image. Specific examples of the recording material P include plain paper, a resin-made sheet that is a substitute for plain paper, cardboard, and an overhead projector sheet. The printer shown in FIG. 2 includes image forming units 10 for each color of Y (yellow), M (magenta), C (cyan), and Bk (black). The photosensitive drum 11 is charged in advance by a charger 12.
Thereafter, a latent image is formed on the photosensitive drum 11 by the laser scanner 13. The latent image becomes a toner image by the developing device 14. The toner image on the photosensitive drum 11 is sequentially transferred to, for example, an intermediate transfer film 31 which is an image carrier by the primary transfer blade 17.

  After the transfer, the toner remaining on the photosensitive drum 11 is removed by the cleaner 15. As a result, the surface of the photosensitive drum 11 becomes clean and prepares for the next image formation.

  On the other hand, the recording material P is sent one by one from the first-stage sheet feeding cassette 20 a, the second-stage cassette 20 b, or the multi-sheet feeding tray 25, and is fed to the registration roller pair 23. The registration roller pair 23 once receives the recording material P and straightens it when the recording material P is skewed.

  The registration roller pair 23 feeds the recording material P between the intermediate transfer film 31 and the secondary transfer roller 35 in synchronization with the toner image on the intermediate transfer film 31. The color toner image on the intermediate transfer film is transferred to the recording material P by, for example, a secondary transfer roller 35 which is a transfer body.

  Thereafter, the toner image on the recording material P is fixed to the recording material P by heating and pressing the recording material P by the fixing device 40. When a toner image is formed only on one side of the recording material P, the recording material P faces the sheet discharge tray 64 disposed on the side surface of the image forming apparatus 1 via the sheet discharge roller 63 by switching the switching flapper 61. The sheet is discharged up (the toner image is on the upper side) or discharged face-down to the sheet discharge tray 65 disposed on the upper surface of the image forming apparatus 1. When toner images are formed on both surfaces of the recording material P, the recording material P on which the toner image has been fixed by the fixing device 40 is guided upward by the flapper 61, and when the trailing edge reaches the reversal point R, the conveyance path 73 is switched back and is turned upside down.

  Thereafter, the recording material P is conveyed through the double-sided conveyance path 70, undergoes a process similar to that for single-sided image formation, forms a toner image on the other side, and is discharged onto the discharge tray 64 or the discharge tray 65. . The portion constituted by the flapper 61, the switchback conveyance path 73, and the like is an example of a reversing unit.

[Configuration of Fixing Device]
Next, the fixing device 40 will be described in detail with reference to the side view of the fixing device in FIG. 4 and the sectional view of the fixing device in FIG.

  The fixing device 40 is a film heating type heating device. The fixing device 40 includes a pressure roller 106 as a pressure member, a ceramic heater 100 as a heating member, a cylindrical film 101 as a fixing member, and a regulating member that is installed at the end of the film 101 and guides the rotation trajectory of the film 101. 104 and a guide member 103 for forming a nip portion N between the film 101 and the pressure roller 106, the film 101, and an inner surface of the film for securing the strength of the guide member The stay 102 is made up of.

  The pressure roller 106 as a pressure member includes a cored bar 106a, a heat-resistant / elastic material layer 106b made of silicone rubber, fluororubber, fluororesin, or the like, which is concentrically molded and coated around the cored bar. The release layer is provided on the surface layer. For example, the release layer may be made of a material having good release properties and heat resistance such as fluororesin, silicone resin, fluorosilicone rubber, fluororubber, silicone rubber, PFA, PTFE, FEP. Bearing members (not shown) made of heat-resistant resin such as PEEK, PPS, liquid crystal polymer, and the like are attached to both ends of the core metal, and are arranged to be rotatably held on the side plate 105.

  A ceramic heater 100 (hereinafter referred to as a heater) as a heating member is basically composed of an elongated thin plate-like ceramic substrate and an energized heating resistor layer provided on the substrate surface. It is a low heat capacity heater that heats up with a steep rise characteristic when energized. The heater 100 is fitted and supported in a fitting groove 103a provided on the lower surface of the guide member 103 along the longitudinal direction (lateral direction in FIG. 4).

  The film 101 is a cylindrical heat-resistant film as a heat generating member that transmits heat to the recording material P, and is loosely fitted to the regulating member 104. The fixing film 101 is formed of a silicone rubber layer (elastic layer), a PFA resin tube on a film (base layer) formed into a seamless film shape having a thickness of 0.04 mm, for example, by drawing a SUS base tube or nickel electroforming. Is coated.

  The guide member 103 is a heat-resistant and heat-insulating member having a substantially semi-circular cross section with the direction intersecting the recording material P conveyance direction as the longitudinal direction. The phenolic resin, polyimide resin, polyamide resin, polyamideimide resin, PEEK resin, A material having good insulation and heat resistance such as PES resin, PPS resin, PFA resin, PTFE resin, and LCP resin is used, and the nip portion N is formed by being in pressure contact with the pressure roller 106.

The stay 102 is a member for imparting longitudinal strength to the guide member 103 and for correcting the guide member 103 by pressing against the back surface of the relatively flexible guide member 103 made of resin.
The restriction member 104 includes an inner surface support portion 104 a and an end surface support portion 104 b and is engaged with both ends of the assembly of the guide member 103 and the stay 102.

  The inner surface support portion 104 a guides rotation by contacting the inner surface of the film 101, and the end surface support portion 104 b regulates movement by contacting the longitudinal end surface of the film 101 when moving in the thrust direction of the film 101. The regulating member 104 is fitted and held on the side plate 105.

  The pressure roller 106 is rotationally driven by a driving unit controlled by a controller of the image forming apparatus via a gear 112 attached to an end portion in the longitudinal direction. The film 101 is driven to rotate by the pressure roller 106.

  Separation member 107 is made by forming a flat plate of a resin such as PBT + ABS, PPS, LCP, or a metal such as SUS, and applying a fluorine coating to the surface. Peeling recording material P after passing through nip N from film 101 To do.

  A configuration according to the first embodiment of the present invention will be described with reference to FIGS. 6, 7, and 8.

  As shown in FIG. 6, the stay end 102 a and the restriction member 104 are engaged by inserting the stay end 102 a into the engagement hole 310 of the restriction member 104. In the conventional example, as shown in FIG. 7, there is a gap 300 in the engagement hole 310 between the regulating member 104 and the stay 102 in the direction of the arrow in FIG. 7 (hereinafter referred to as the conveyance direction). The gap 300 is about 0.7 mm, for example.

  In contrast to the conventional example, in this embodiment, an elastic member 201 is provided at the stay end 102a as shown in FIG. The elastic member 201 is a member that deforms when a force is applied, but returns to the original when the force is removed. For example, the elastic member 201 is a member such as silicon rubber or a spring. When the stay 102 is engaged with the regulating member 104, the elastic member 201 is attached so that the width in the conveyance direction is crushed from 1.4 mm to 0.7 mm. As a result, there is no gap between the stay end 102a and the regulating member 104. At this time, the spring coefficient k of the stay 102 was 2.0 N / mm in the conventional example, but increased to 2.7 N / mm in the present example.

  The effects of this embodiment will be described below.

  First, conditions will be described. The elastic member 201 is made of silicon rubber. The temperature of the heater 100 was set to 180 ° C., and the pressure applied to the pressure roller 106 was set to a constant condition of 150N.

  Next, an effect confirmation method will be described. The speed of the film 101 was changed, and the speed at which abnormal noise due to stick-slip occurred was confirmed.

  In the above conditions and method, in the conventional configuration, abnormal noise was generated when the speed of the film 101 was 75 mm / s or less. In this example, abnormal noise was generated when the speed of the film 101 was 65 mm / s or less. Stick-slip is unlikely to occur when the film speed is high and is likely to occur when the film speed is slow. For this reason, abnormal noise is less likely to occur when the film speed is high, and is likely to occur when the film speed is slow. Therefore, as compared with the conventional example, it becomes worse when abnormal noise is generated at a higher film speed, and improved when abnormal noise is generated only at a slower film speed.

  In this example, compared with the conventional example, there was an effect that generation of abnormal noise caused by stick-slip was improved by 10 mm / s.

  The reason for the above effects will be described.

  In the conventional example, there is a gap 300 between the stay end 102a and the regulating member 104 as shown in FIG. The presence of the gap 300 causes the stay 102 to vibrate in the transport direction as the film 101 slides. The stay 102 is connected to the heater 100 through the guide member 103. Therefore, the vibration in the conveying direction of the stay 102 in the engagement hole 310 increases the stick-slip of the heater 100 and promotes the generation of abnormal noise.

  On the other hand, in this embodiment, the stay end 102 a is pressed against the regulating member 104 by the elastic member 201. Therefore, the vibration constant of the elastic member 201 is added to the spring constant of the stay 102 in the vibration in the conveying direction of the stay end 102 a in the engagement hole 310. From the equation of Hook's law F = kx, when the load F is constant, the amplitude x decreases as the spring constant k increases. Since there is no change in the force F applied to the stay 102 between this embodiment and the conventional example, the vibration (amplitude x) of the stay 102 is reduced, and the generation of abnormal noise is suppressed.

  The elastic member described in the present embodiment refers to a member having a Young's modulus of 30 MPa or less. Further, in this embodiment, the elastic member 201 is made of silicon rubber or a spring. However, the elastic member 201 may be a member to which an elastic force is applied, such as a sponge, and does not limit the scope of the present invention.

  Next, the form of Example 2 is demonstrated using FIG.

First the length _{X 1} between the engaging hole 310 of the regulating member 104 as shown in FIG. 9, the length _{Y 1} between the stay ends 102a to the relationship of _X 1> _{Y 1.} Since the stay 102 is a metal part and the restriction member 104 is a resin material part, the rigidity of the restriction member 104 is smaller than the rigidity of the stay 102. Therefore, when the stay 102 is attached to the engagement hole 310, the regulating member 104 is elastically deformed. Then, the attaching the stay 102 in a state in which shrink the length X ₁ between the engagement holes 310. Since the regulating member 104 generates a force to return to the original shape after the attachment, the regulating member 104 comes into contact with the stay end portion 102a so as to expand. Since X ₁ > Y ₁ at the time of non-engagement, the regulating member 104 always comes into close contact with the stay end 102a. Therefore, the vibration constant in the conveying direction of the stay end 102 a in the engagement hole 310 adds the spring constant of the restricting member 104 to the spring constant of the stay 102. From the above, abnormal noise is improved for the same reason as in the first embodiment.

Further, the case where the length between the engagement holes 310 of the restricting member 104 and the length between the stay end portions 102a are set as X ₂ and Y ₂ respectively and will be described as shown in FIG. In FIG. 10, the relationship between X ₂ and Y ₂ is set to Y ₂ > X ₂ . Since the rigidity of the restriction member 104 is smaller than the rigidity of the stay 102, the restriction member 104 is elastically deformed when the stay 102 is attached to the engagement hole 310. Then, the attaching the stay 102 in our extended length _{X 2} between the engaging hole 310. Since the restriction member 104 generates a force to return to the original shape after the attachment, the restriction member 104 comes into contact with the stay end portion 102a so as to narrow. At the time of non-engagement, since Y ₂ > X ₂ , the regulating member 104 always comes into close contact with the stay end 102a. Therefore, the vibration constant in the conveying direction of the stay end 102 a in the engagement hole 310 adds the spring constant of the restricting member 104 to the spring constant of the stay 102. From the above, abnormal noise is improved for the same reason as in the first embodiment.

  Next, the form of Example 3 is demonstrated using FIG.11, FIG.12, FIG.13.

  As shown in FIG. 11, the claw portion 104 c is added to the restricting member 104 in the engagement hole 310. The stay end portion 102a is recessed to provide a claw catching portion 102b. The claw catching portion 102 b is for preventing the regulating member 104 from coming off the stay 102.

FIG. 12 is a view showing the claw portion 104c of the restricting member 104 and a perspective view A when the cross section of the stay 102 is cut and viewed from the direction of the arrow so that the groove bottom portion of the claw catching portion 102b of the stay 102 can be seen. 3 is a cross-sectional view of a stay 102. FIG. In FIG. 12, it is assumed that Y ₃ > X ₃ with respect to the length Y ₃ between the claw catching portions 102b of the stay 102 and the length X ₃ between the claw portions 104c. If the stay 102 is to be attached to the engagement hole 310 at this time, the claw portion 104c is elastically deformed in the transport direction in order to avoid the stay end portion 102a. Therefore, when the stay 102 is attached to the regulating member 104, the claw portion 104c attempts to return to its original shape as shown in FIG. At the time of non-engagement, since Y ₃ > X ₃ , the regulating member 104 generates the force even while engaged. The stay end 102a is pressed against the regulating member 104 by the force. Therefore, in the vibration in the conveying direction of the stay end portion 102 a in the engagement hole 310, the spring constant of the restricting member 104 is added to the spring constant of the stay 102. Therefore, abnormal noise is improved for the same reason as in the first embodiment.

  The form of Example 4 is demonstrated using FIG.

  In the engagement hole 310, a fastening hole 320 penetrating in the conveying direction of the regulating member 104 is formed. Further, the stay end portion 102a is recessed and a fastening member receiver 102c is provided. After the stay 102 is engaged, the fastening member 202 is fastened to the fastening hole 320. When the end portion of the fastening member 202 passes through the fastening hole 320, the fastening member receiver 102 c can be contacted and the stay end portion 102 a can be pressed against the regulating member 104. As a result, vibration in the conveying direction of the stay end portion 102 a in the engagement hole 310 can be suppressed by the fastening member 202. Therefore, the vibration of the stay 102 is reduced and the generation of abnormal noise is suppressed.

40 fixing device, 100 ceramic heater, 101 cylindrical film,
102 stay, 102a stay end, 102b claw catching part,
102c fastening member receiver, 103 guide member, 104 regulating member,
104a inner surface support portion, 104b end surface support portion, 104c claw portion,
106 pressure roller, 107 separating member, 201 elastic member, 202 fastening member,
300 Clearance in the conveying direction between the restricting member and the stay end in the engagement hole,
310 engagement hole when inserting the stay into the restricting member, 320 fastening hole,
N Nip part

Claims (5)

A rotating pressure body (106);
A sleeve-like film (101) that forms a nip with the pressure body (106) and rotates with the pressure body (106);
A regulating member (104) for regulating the trajectory of the film (101);
A rigid structure (102) disposed within the film (101) and supported by the regulating member (104);
In the fixing device (40) for heating the material to be heated (100) through the nip portion,
A fixing device having at least one elastic member (201) having elasticity between the structure (102) and the regulating member (104). The fixing device according to claim 1, wherein the elastic member (201) restricts a gap (300) generated in a conveyance direction of the restricting member (104) and the structure (102). A rotating pressure body (106);
A sleeve-like film (101) that forms a nip with the pressure body (106) and rotates with the pressure body (106);
A regulating member (104) for regulating the trajectory of the film (101);
A rigid structure (102) disposed within the film (101) and supported by the regulating member (104);
In the fixing device (40) for heating the material to be heated (100) through the nip portion,
The fixing device, wherein the regulating member (104) is elastically deformed in the transport direction between the structure (102) and the regulating member (104). A rotating pressure body (106);
A sleeve-like film (101) that forms a nip with the pressure body (106) and rotates with the pressure body (106);
A regulating member (104) for regulating the trajectory of the film (101);
A rigid structure (102) disposed within the film (101) and supported by the regulating member (104);
In the fixing device (40) for heating the material to be heated (100) through the nip portion,
A fixing device having a fastening member (202) between the structure (102) and the regulating member (104). The fastening member (202) presses the structural body (102) against the regulating member (104) in a gap (300) generated in the transport direction of the structural body (102) and the regulating member (104). The fixing device according to claim 4.