Opening and closing device, image forming apparatus including opening and closing device, and gas spring unit for image forming apparatus

Abstract

To provide an opening and closing device capable of enhancing workability of replacing gas springs performed by an operator.SOLUTION: A fitting support member 14 at a cover-side end portion of a gas spring units 10 is pivotably fitted to a cover-side fitting member 30 of a top cover 450. A fitting support member 13 at a housing-side end portion of the gas spring units 10 is pivotably fitted to a housing-side fitting member 20 provided in a housing 420. The housing-side fitting member 20 is provided with a guide pocket 60. A movement range in a lateral direction of the gas spring unit 10 is restricted when side guides 61 of the guide pocket 60 come into contact with end surfaces of a shaft portion of the fitting support member 13. Meanwhile, a movement range in an insertion direction of the gas spring unit 10 is restricted when rear guide portions 23 come into contact with side surfaces of the shaft portion of the fitting support member 13. Then, the gas spring unit 10 is guided into a U-shaped groove 21 of the housing-side fitting member 20 by lower end portions 23a of the rear guide portions 23.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an opening / closing device for opening and closing a cover provided on a housing, an image forming apparatus including the opening / closing device, and a gas spring unit for an image forming apparatus. [Background technology]

[0002] As an electrophotographic or inkjet image forming apparatus, a device having an openable cover provided on the top surface of the housing has been proposed. Patent Document 1 discloses an inkjet recording apparatus that forms an image on a sheet with ink. In the inkjet recording apparatus, for example, a conveying roller that conveys the sheet, an ink drying section that dries the ink attached to the sheet, and a fixing roller that fixes the ink on the sheet after drying are arranged along the conveying path along which the sheet is conveyed. The housing that contains them is provided with an openable cover on the top, and parts of the conveying roller, ink drying section, fixing roller, etc. are arranged on this cover so that they can be lifted together with the cover. An operator can open the cover to perform so-called jam processing work to remove a sheet that has become clogged in the conveying path, and maintenance work such as cleaning the conveying roller, ink drying section, and fixing roller.

[0003] As described above, when the conveying roller, the ink drying unit, and part of the fixing roller are arranged on the cover, the weight of the cover including them becomes heavy. Therefore, in order to enable the operator to open and close the cover smoothly, an opening and closing device that uses a gas spring to assist in opening and closing the cover has been proposed (Patent Document 2). One end of the gas spring is rotatably supported by the cover, and the other end is fixed to the housing using a screw or the like. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-188624 A [Patent Document 2] JP 2007-121588 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, gas inside a gas spring may gradually leak due to repeated use. This will reduce the reaction force generated by the compressed gas, making it necessary to replace the gas spring. However, in the past, gas springs were fixed to a cover or a housing as described above. Also, in order to assist in opening and closing a heavy cover, a gas spring that is long in the expansion and contraction direction and has a large reaction force was used, and the other end of the gas spring had to be fixed at a position deep inside the housing away from the cover. Therefore, in order to replace the gas spring, an operator had to remove other units housed in the housing, which was time-consuming and troublesome.

[0006] The present invention has been made in consideration of the above problems, and aims to provide an opening / closing device that can improve the ease with which an operator can replace a gas spring that assists in opening and closing a cover, an image forming apparatus equipped with an opening / closing device, and a gas spring unit for an image forming apparatus. [Means for solving the problem]

[0007] An opening and closing device according to an embodiment of the present invention comprises a housing having an opening on an upper surface, a cover that is rotatably provided on the housing around a rotation axis along a first direction and opens and closes the opening, and a gas spring unit that has a cover side end that fits with the cover and a housing side end that fits with the housing, and that expands and contracts as the cover rotates, wherein the cover side end of the gas spring unit has a cover side shaft extending along the first direction, the cover has a cover side fitting portion that fits with the cover side shaft, and the cover side shaft fits into the cover side fitting portion, so that the gas spring unit is in a state where it is rotatable around the cover side axis relative to the cover, and the gas spring unit the housing side end of the gas spring has a housing side axis extending in the first direction, the housing has a housing side fitting portion that fits with the housing side axis, the housing supports the gas spring unit in a state in which the gas spring unit can rotate around the housing side axis relative to the housing by fitting the housing side axis into the housing side fitting portion, and when the housing side end of the gas spring unit is inserted into the housing from the opening, the housing side axis abuts against the housing side axis to limit the movement range of the gas spring unit and guide the housing side axis to a position where it fits with the housing side fitting portion.

[0008] A gas spring unit according to one embodiment of the present invention comprises a first gas spring which expands and contracts along a first direction, a second gas spring which expands and contracts along the first direction, a first shaft which extends along a second direction intersecting the first direction, and a second shaft which extends along the second direction, wherein both ends of the first gas spring and the second gas spring are provided with through holes, the first shaft is inserted into the through hole at one end of the first gas spring and the through hole at one end of the second gas spring, and the second shaft is inserted into the through hole at the other end of the first gas spring and the through hole at the other end of the second gas spring. Effect of the Invention

[0009] According to the present invention, it is possible to improve the ease with which an operator can replace a gas spring unit that assists in opening and closing a cover provided on a housing. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing an inkjet recording apparatus suitable for using the opening and closing device of the present embodiment. [Diagram 2] FIG. 4 is a perspective view showing a state in which the top cover of the fixing module is open. [Diagram 3] FIG. 2 is a right side view showing the opening / closing device of the present embodiment. [Figure 4] FIG. 1 is a front view showing a gas spring unit, (a) when an E-type retaining ring is used for the fixing ring, and (b) when a shaft collar is used for the fixing ring. [Diagram 5] FIG. 13 is a diagram for explaining replacement of a gas spring unit. [Figure 6] FIG. 1A is a top view showing the guide pocket, FIG. 1B is a left side view showing the guide pocket, FIG. 1C is a front view showing the guide pocket, and FIG. [Figure 7] 1A and 1B are a front view and a right side view, respectively, showing a gas spring unit provided with a positioning member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, an image forming apparatus suitable for using the opening and closing device of this embodiment will be described with reference to FIG. 1. Here, as an example of the image forming apparatus, a so-called sheet-fed inkjet recording apparatus 100 that forms an image on a sheet using ink and a reaction liquid will be described. The sheet may be any recording material that can receive ink, such as paper such as plain paper or cardboard, plastic film such as an overhead projector sheet, specially shaped sheets such as envelopes or index paper, and cloth.

[0012] In this specification, the side on which an operator stands when operating the inkjet recording apparatus 100 is referred to as the "front (or front)" and the opposite side is referred to as the "rear (or rear)". Furthermore, the left side as viewed from the front is referred to as the "left" and the right side as viewed from the front is referred to as the "right". Figure 1 shows the inkjet recording apparatus 100 as viewed from the front.

[0013] <Inkjet recording device> 1, the inkjet recording apparatus 100 includes a paper feed module 1000, a print module 2000, a drying module 3000, a fixing module 4000, a cooling module 5000, an inverting module 6000, and a stacking module 7000. A sheet S supplied from the paper feed module 1000 undergoes various processes while being transported along a transport path within each module, and is finally discharged into the stacking module 7000. The sheet S is an example of a medium on which an image is formed.

[0014] The paper feed module 1000, print module 2000, drying module 3000, fixing module 4000, cooling module 5000, reversing module 6000, and stacking module 7000 may each have a separate housing, and these housings may be connected to configure the inkjet recording apparatus 100. Alternatively, the paper feed module 1000, print module 2000, drying module 3000, fixing module 4000, cooling module 5000, reversing module 6000, and stacking module 7000 may be arranged in a single housing.

[0015] The paper feed module 1000 has storage chambers 1500a, 1500b, and 1500c for storing sheets S, and the storage chambers 1500a to 1500c are provided so as to be able to be pulled out to the front side of the apparatus in order to store the sheets S. The sheets S are fed one by one in each of the storage chambers 1500a to 1500c by a separation belt and a transport roller, and are transported to the print module 2000. The number of storage chambers 1500a to 1500c is not limited to three, and one, two, or four or more may be provided.

[0016] The print module 2000 has a pre-imaging registration correction section (not shown), a print belt unit 2200, and a recording section 2300. The sheet S conveyed from the paper feed module 1000 has its inclination and position corrected by the pre-imaging registration correction section and is conveyed to the print belt unit 2200. The recording section 2300 is disposed at a position facing the print belt unit 2200 with respect to the conveyance path. The recording section 2300 as an image forming section performs recording processing (printing) on ​​the conveyed sheet S from above with a recording head to form an image. The sheet S is attracted and conveyed by the print belt unit 2200, so that a clearance with the recording head is secured. The recording head has a plurality of recording heads arranged along the conveyance direction, for example, four colors of Y (yellow), M (magenta), C (cyan), and Bk (black), as well as a total of five line-type recording heads corresponding to reaction liquids.

[0017] The number of ink colors and recording heads are not limited to five. The inkjet method may be a method using a heating element, a method using a piezoelectric element, a method using an electrostatic element, a method using a MEMS (Micro Electro Mechanical Systems) element, or the like. Ink of each color is supplied to the recording head from an ink tank (not shown) via an ink tube. The sheet S printed by the recording section 2300 is transported by the print belt unit 2200, and an in-line scanner (not shown) arranged downstream of the recording section in the transport direction can detect the misalignment and color density of the image formed on the sheet S and correct the printed image.

[0018] The drying module 3000 includes a decoupling section 3200, a drying belt unit 3300, and a hot air blowing section 3400. The drying module 3000 reduces the liquid content of the ink applied to the sheet S in order to improve the fixation of the ink to the sheet S by the subsequent fixing module 4000. The sheet S on which an image has been formed is transported to a decoupling section 3200 arranged in the drying module 3000. In the decoupling section 3200, frictional force is generated between the sheet S and the belt by the wind pressure of the wind blown from above, and the sheet S is transported by the belt. In this way, the sheet S placed on the belt is transported by frictional force, thereby preventing the sheet S from shifting when the sheet S is transported between the print belt unit 2200 and the decoupling section 3200.

[0019] The sheet S conveyed from the decoupling section 3200 is sucked and conveyed by the drying belt unit 3300, and the ink applied to the sheet S is dried by blowing hot air from the hot air blowing section 3400 arranged above the belt. The ink applied to the sheet S is heated by the drying module 3000 to promote evaporation of moisture, thereby suppressing the occurrence of so-called cockling, in which ink is scattered on the sheet S and a line like a border is formed around the periphery. The drying module 3000 may be any device that can heat and dry the sheet S, but a hot air dryer or a heater is preferable. As the heater, for example, heating by an electric heating wire or an infrared heater is preferable from the viewpoint of safety and energy efficiency.

[0020] The fixing module 4000 has a fixing belt unit 4100. The fixing belt unit 4100, which serves as a conveying section, fixes ink onto the sheet S by passing the sheet S conveyed from the drying module 3000 between a heated upper belt 4110 and a lower belt 4120. The upper belt 4110 and the lower belt 4120 come into contact with each other to form a sheet conveying path 1 along which the sheet S is conveyed.

[0021] The cooling module 5000 has a plurality of cooling sections 5100, which cool the high-temperature sheet S transported from the fixing module 4000. The cooling section 5100, for example, takes in outside air with a fan into a cooling box to increase the pressure inside the cooling box, and cools the sheet S by blowing air from the cooling box through a nozzle due to the pressure against the sheet S. The cooling sections 5100 are disposed on both sides of the transport path of the sheet S, and cool both sides of the sheet S.

[0022] The cooling module 5000 is provided with a conveying path switching unit 5002. The conveying path switching unit 5002 switches the conveying path of the sheet S depending on whether the sheet S is to be conveyed to the reversing module 6000 or to a double-sided conveying path for double-sided printing in which images are formed on both sides of the sheet S.

[0023] The inversion module 6000 has an inversion section 6400. The inversion section 6400 inverts the sheet S being conveyed, and changes the orientation of the sheet S when it is discharged to the stacking module 7000. The stacking module 7000 has a top tray 7200 and a stacking section 7500, and stacks the sheet S conveyed from the inversion module 6000.

[0024] During double-sided printing, the sheet S is conveyed to a conveyance path below the cooling module 5000 by the conveyance path switching unit 5002. Thereafter, the sheet S passes through a double-sided conveyance path of the fixing module 4000, the drying module 3000, the print module 2000, and the paper feed module 1000, and is returned to the print module 2000. The double-sided conveyance section of the fixing module 4000 is provided with an inversion unit 4200 that inverts the sheet S. The sheet S returned to the print module 2000 has an image formed with ink on the other side on which the image is not formed, and is discharged to the stacking module 7000 via the drying module 3000, the fixing module 4000, the cooling module 5000, and the inversion module 6000.

[0025] Incidentally, for example, in the fixing module 4000, a sheet may become jammed in the sheet conveying path 1 formed by the upper belt 4110 and the lower belt 4120. In that case, a control unit (not shown) detects a jam of the sheet S based on a signal from a detection sensor (not shown) disposed in the sheet conveying path 1. When a jam of the sheet S is detected, an operator needs to expose the sheet conveying path 1 in order to remove the sheet S remaining in the sheet conveying path 1.

[0026] 2 is a perspective view showing a state in which the top cover 450 of the fixing module 4000 is open. The top cover 450 is rotatable about a rotation axis along a first direction. In this embodiment, the first direction is the same as the conveying direction of the sheet S. When the top cover 450 is closed, the opening 420a of the housing 420 is covered, whereas when the top cover 450 is open, the opening 420a of the housing 420 is exposed. That is, the top cover 450 opens and closes the opening 420a on the top surface of the housing.

[0027] 2, an operator can expose a sheet transport path 1 (see FIG. 1) from an opening 420a by lifting up a top cover 450 provided on a housing 420 of the fixing module 4000, and remove the sheet S from the sheet transport path 1. The top cover 450 is provided rotatably with respect to the housing 420 of the fixing module 4000, with a cover rotation shaft 410 (see FIG. 3) provided on the rear side as a rotation center. The top cover 450 has a handle 430 on the front side, which makes it easy for an operator to hold the handle 430 and lift the top cover 450 upward.

[0028] The upper belt 4110 as a first conveyor belt is disposed on the top cover 450 and moves integrally with the top cover 450. In accordance with the opening and closing of the top cover 450, the upper belt 4110 moves between an abutting position where it abuts against the lower belt 4120 as a second conveyor belt to form the sheet conveying path 1 and a separating position where it separates from the lower belt 4120 to open the sheet conveying path 1. When the upper belt 4110 is in the separating position, the sheet conveying path 1 is exposed, and an operator can remove the sheet S remaining on the lower belt 4120. In this embodiment, the top cover 450 including the upper belt 4110 is rotatably supported on the rear side, so that the front side of the top cover 450 can be opened upward.

[0029] <Switchgear> The weight of the top cover 450 including the upper belt 4110 described above exceeds, for example, 700N. Therefore, in this embodiment, an opening / closing device 400 for assisting in opening and closing the top cover 450 is provided in the fixing module 4000. The opening / closing device 400 will be described with reference to Figs. 3 to 7(b). Fig. 3 is a right side view showing the opening / closing device 400.

[0030] As shown in FIG. 3, the top cover 450 is rotatably connected to the housing 420 of the fixing module 4000 by a cover rotation shaft 410 provided on the rear side. The opening / closing device 400 has a gas spring unit 10 for assisting an operator in opening and closing the top cover 450. The gas spring units 10 are disposed on both ends of the top cover 450 in the left-right direction (see FIG. 2), and are disposed in a position closer to the cover rotation shaft 410 of the top cover 450 than the lower belt 4120 in the front-rear direction inside the housing 420 (inside the housing). One end of the gas spring unit 10 is rotatably connected to a cover-side fitting member 30 provided on the top cover 450. On the other hand, the other end of the gas spring unit 10 is rotatably connected to a housing-side fitting member 20 provided in the housing 420. For convenience, the end connected to the top cover 450 is called the cover-side end, and the end connected to the housing-side fitting member 20 is called the housing-side end. In this embodiment, the gas spring unit 10 expands and contracts in a direction intersecting the rotation axis direction of the top cover 40.

[0031] <Gas spring unit> A gas spring unit 10 for an image forming apparatus in this embodiment will be described with reference to Fig. 4(a). As shown in Fig. 4(a), the gas spring unit 10 has a first gas spring 11 and a second gas spring 12. These gas springs 11 and 12 are arranged side by side in a direction intersecting the direction of expansion and contraction (left and right direction in this embodiment) so that their expansion and contraction directions are the same. Through holes are formed at both ends of each of the gas springs 11 and 12. Note that the gas springs 11 and 12 are not limited to being arranged side by side in the left and right direction, and may be arranged side by side in the front and rear direction.

[0032] These gas springs 11 and 12 have a rod and a tube, and the rod-side end portions 11a and 12a (housing-side end portions) disposed in the housing 420 are fixed to a fitting support member 13 having a shaft portion extending in the rotational axis direction of the top cover 450. The fitting support member 13 is inserted through a through hole formed at the other end of the gas spring 11 and a through hole formed at the other end of the gas spring 12. On the other hand, the tube-side end portions 11b and 12b (cover-side end portions) disposed on the top cover 40 are fixed to a fitting support member 14 having a shaft portion extending in the rotational axis direction of the top cover 450. The fitting support member 14 is inserted through a through hole formed at one end of the gas spring 11 and a through hole formed at one end of the gas spring 12. Note that the housing-side end portion and the cover-side end portion are defined by the installation direction of the gas springs 11 and 12. For example, when the tube-side end portions 11b and 12b are disposed on the housing 420, the tube-side end portions 11b and 12b become the housing-side end portions.

[0033] The fitting support member 13 is a housing-side shaft, and the fitting support member 14 is a cover-side shaft. Step portions 13a and 14a (intermediate portions) having a diameter larger than that of the shaft portion are provided on the shaft portions of the fitting support members 13 and 14 (the first shaft and the second shaft), respectively. The step portions 13a and 14a enable the rod-side end portions 11a and 12a and the tube-side end portions 11b and 12b of the gas springs 11 and 12 to be arranged on the shaft portion at a predetermined interval so that the gas springs 11 and 12 do not contact each other. The fixing ring 15 fixes the rod-side end portions 11a and 12a and the tube-side end portions 11b and 12b of the gas springs 11 and 12 so as not to move in the left-right direction from the shaft portions of the fitting support members 13 and 14. As the fixing ring 15, for example, an E-ring is used. The length C of the fitting support members 13 and 14 is longer than the width A outside the tubes of the gas springs 11 and 12 arranged in parallel (A < C in the figure). In the present embodiment, the rod-side end portions 11a and 12a, the step portion 13a, the fitting support member 13, and the fixing ring 15 are components included in the housing-side end portion of the gas spring unit 10. Also, the tube-side end portions 11b and 12b, the step portion 14a, the fitting support member 14, and the fixing ring 15 are components included in the cover-side end portion of the gas spring unit 10.

[0034] The fixing ring 15 is not limited to an E-type retaining ring as shown in FIG. 4(a). For example, as shown in FIG. 4(b), a shaft collar 17 may be used as the fixing ring 15, and the shaft collar 17 may be fixed to the fitting support members 13, 14 by a set screw 16. In this case, the relationship between the width A of the outer tubes of the gas springs 11, 12 arranged in parallel, the outer spacing B of the shaft collar 17, and the length C of the fitting support members 13, 14 is "A <B<C」となる。

[0035] <Gas spring unit connection> Next, the connection between the gas spring unit 10 and the cover side fitting member 30 and the housing side fitting member 20 will be described. As shown in Fig. 3, the cover side fitting member 30 is provided inside the top cover 450 at both left and right ends. The cover side fitting member 30 has a convex portion that protrudes downward from the lower end of the top cover 450, and a U-shaped groove 31 is formed at the tip of the convex portion. The shaft portion of the fitting support member 14 that fixes the tube side ends 11b and 12b of the gas springs 11 and 12 is fitted into the U-shaped groove 31, so that the gas spring unit 10 is connected to the cover side fitting member 30 so as to be rotatable about an axis approximately parallel to the cover rotation axis 410 and to be detachable.

[0036] On the other hand, housing side fitting members 20 are provided inside the housing 420 at both left and right ends. A U-groove 21 is formed as a recess in the bottom of the housing side fitting member 20. The shaft portion of the fitting support member 13 to which the rod side ends 11a, 12a of the gas springs 11, 12 are fixed is fitted into the U-groove 21, whereby the gas spring unit 10 is detachably connected to the housing side fitting member 20 so as to be rotatable about an axis approximately parallel to the cover rotation axis 410.

[0037] Gas is sealed in the tubes of the gas springs 11 and 12, and the gas generates a reaction force in the gas springs 11 and 12 according to the expansion and contraction state of the rod relative to the tube. In the case of the gas spring unit 10 of this embodiment, in each of the gas springs 11 and 12, when the top cover 450 is closed, the rod enters the tube, and the gas in the tube is compressed by the rod. Then, when the top cover 450 is opened, a reaction force is generated by the compressed gas in the gas springs 11 and 12, which assists the opening operation of the top cover 450, and the operator can open the top cover 450 smoothly.

[0038] However, the gas springs 11 and 12 may deteriorate over the product lifespan, and therefore need to be replaced periodically or when they are accidentally broken. In the commercial printing market, the availability of the inkjet recording device 100 is one of the indicators that workers place importance on, so it is also required that the gas spring unit 10 described above can be quickly and reliably replaced by a worker. Therefore, in this embodiment, as described above, a connection structure is adopted in which the shaft portion of the fitting support member 14 is detachably fitted into the U-groove 31 of the cover-side fitting member 30, and the shaft portion of the fitting support member 13 is detachably fitted into the U-groove 21 of the housing-side fitting member 20.

[0039] The replacement work of the gas spring unit 10 will be described. As shown in FIG. 5, when replacing the gas spring unit 10, the worker pulls up the handle 430 formed on the front side of the top cover 450 and rotates the top cover 450 upward. In the case of this embodiment, as described above, the drying module 3000 is arranged upstream of the fixing module 4000 with respect to the conveying direction of the sheet S, and the cooling module 5000 is arranged downstream of the fixing module 4000, so that it is difficult to access from the left or right side to replace the gas spring unit 10. Therefore, in this embodiment, the front side of the top cover 450 is lifted and supported by the cover support member 50 in an open state, so that the worker can access the inside of the housing 420 from the front to replace the gas spring unit 10.

[0040] When the gas spring unit 10 is removed, the top cover 450 is supported by the cover support member 50 in an open state to a maintenance position that is more open than during jam clearance work. At this time, the gas springs 11, 12 of the gas spring unit 10 are in a free length state, and the shaft portion of the fitting support member 14 is out of the U-groove 31 of the cover-side fitting member 30. In other words, when the top cover 450 is rotated greater than a predetermined rotation amount with the gas spring unit 10 attached, the shaft portion of the fitting support member 14 is released from engagement with the U-groove 31 of the cover-side fitting member 30. The cover support member 50 supports the top cover 450 in a state rotated greater than a predetermined rotation amount.

[0041] This allows the worker to hold the gas spring unit 10 positioned further back than the lower belt 4120 from the opening 420a, and move the held gas spring unit 10 diagonally forward (in the direction of arrow D in FIG. 5), avoiding the lower belt 4120. As the gas spring unit 10 is moved diagonally forward, the shaft portion of the fitting support member 13 disengages from the U-groove 21 of the housing-side fitting member 20, and the worker can remove the gas spring unit 10 from the housing 420.

[0042] The cover support member 50 may be attached to the housing 420 in advance, or may not be attached to the housing 420, but may be prepared separately and attached from the outside.

[0043] Conversely, when the gas spring unit 10 is attached, with the top cover 450 supported by the cover support member 50, the gas spring unit 10 is inserted into the housing 420 from the opening 420a in the direction opposite to the arrow D, with the fitting support member 13 side leading. The housing-side fitting member 20 is provided with a guide pocket 60 as a guide portion for guiding the gas spring unit 10. The guide pocket 60 is provided to limit the movement range of the gas spring unit 10 by the fitting support member 13 coming into contact with the guide pocket 60, and to guide the gas spring unit 10 to a position where the shaft portion of the fitting support member 13 and the U-groove 21 of the housing-side fitting member 20 are fitted together.

[0044] The guide pocket 60 will be described. As shown in Fig. 6(a) to Fig. 6(d), the guide pocket 60 has side guides 61 extending in the vertical direction at both ends in the left-right direction, and a front guide 62 arranged so as to span the side guides 61 on the front side. Also, the housing-side fitting member 20 has a back guide portion 23 extending in the vertical direction at both ends in the left-right direction. The side guides 61, the front guide 62, and the back guide portion 23 of the housing-side fitting member 20 form an insertion / removal opening 60a through which the gas spring unit 10 can be inserted and removed. When the gas spring unit 10 is inserted into the inside through the insertion / removal opening 60a, the fitting support member 13 moves within a space surrounded by the side guides 61, the front guide 62, and the back guide portion 23 of the housing-side fitting member 20. At this time, the fitting support member 13 is sandwiched between the two side guides 61 in the left-right direction (rotation axis direction). Therefore, the tip surface of the shaft of the fitting support member 13 comes into contact with the side guide 61 as a first restricting portion, thereby restricting the left-right range (rotation axis direction) of the gas spring unit 10. The side guides 61 are disposed opposite each other so as to sandwich the fitting support member 13 in the left-right direction, and have flat plate portions which come into contact with the tip surface of the fitting support member 13 to restrict the left-right movement range of the gas spring unit 10.

[0045] The rear guide portion 23 as the second restricting portion extends from the insertion / removal opening 60a to the U-groove 21 of the housing-side fitting member 20. When the fitting support member 13 moves in the space surrounded by the side guide 61, the front guide 62, and the rear guide portion 23 of the housing-side fitting member 20, the side of the shaft portion of the fitting support member 13 comes into contact with the rear guide portion 23, thereby restricting the movement range of the gas spring unit 10 in the insertion direction. The lower end portion 23a of the rear guide portion 23 is formed in an inclined shape from the rear surface 20a side of the housing-side fitting member 20 toward the U-groove 21 side of the housing-side fitting member 20. After the side of the shaft portion of the fitting support member 13 comes into contact with the lower end portion 23a, the shaft portion of the fitting support member 13 slides in contact with the lower end portion 23a. In other words, the fitting support member 13 is guided to the fitting position by the lower end portion 23a. Therefore, by inserting the gas spring unit 10 while abutting the shaft portion of the fitting support member 13 against the rear guide 63 from the front side, the worker can reliably fit the shaft portion of the fitting support member 13 into the U-groove 21 of the housing-side fitting member 20. In this way, the worker can easily install the gas spring unit 10.

[0046] As described above, in this embodiment, the fitting support member 14 (cover side shaft) at the cover side end of the gas spring unit 10 is rotatably fitted to the cover side fitting member 30 of the top cover 450. The fitting support member 13 (housing side shaft) at the housing side end of the gas spring unit 10 is rotatably fitted to the housing side fitting member 20 provided in the housing 420. The housing side fitting member 20 is provided with a guide pocket 60 for guiding the gas spring unit 10. The guide pocket 60 limits the range of movement of the gas spring unit 10 in the left-right direction by contacting the side guide 61 with the tip surface of the shaft of the fitting support member 13. In addition, the back guide portion 23 is in contact with the side surface of the shaft of the fitting support member 13, thereby restricting the movement of the gas spring unit 10 in the insertion direction. The gas spring unit 10 is guided to the U-groove 21 of the housing side fitting member 20 by the lower end portion 23a of the back guide portion 23. In this way, when an operator installs the gas spring unit 10, the operator simply inserts the gas spring unit 10 along the guide pocket 60, so that the shaft portion of the fitting support member 13 can be securely fitted into the U-groove 21 of the housing-side fitting member 20. This improves the ease with which an operator can replace the gas spring.

[0047] In order to smoothly open and close the top cover 450, which weighs more than 700N, it is necessary to use a gas spring with a large extension force. Standard gas springs are designed so that the extension force is larger as the maximum length of the gas spring increases. Therefore, in order to assist the opening and closing of the top cover 450, which weighs more than 700N, it is necessary to use a gas spring with a large maximum length. However, in order to do so, it is necessary to secure a large space in the housing 420 in which the gas spring can expand and contract, which may result in the housing 420 becoming larger. In addition, if two gas springs with a large extension force are used and one of them breaks down for some reason, the auxiliary force of the gas spring is halved, which not only makes it difficult to smoothly open and close the top cover 450, but also may compromise safety during replacement work.

[0048] In contrast, in this embodiment, gas spring units 10 each consisting of two gas springs 11, 12 connected together are disposed between the top cover 450 and the housing 420, one on each side. This makes it possible to reduce the size of the housing 420 and the operating space for the gas springs. In addition, because multiple gas springs (four or more) are used, the auxiliary force does not change suddenly even if the extension force of each gas spring decreases due to different aging, and this also increases safety during replacement work. This embodiment is advantageous because even when such a gas spring unit 10 is used, the gas spring unit 10 can be easily replaced.

[0049] <Other embodiments> However, gas in the tubes of the gas springs 11 and 12 of the gas spring unit 10 gradually leaks due to repeated use, and the extension force of the gas springs 11 and 12 may decrease. The gas springs 11 and 12 leak gas in different ways from the tubes. Therefore, it is preferable that the gas springs 11 and 12 can be removed separately from the gas spring unit 10 and replaced. In other words, the gas springs 11 and 12 are not fixed to the fitting support members 13 and 14, but are provided so as to be detachable from the fitting support members 13 and 14.

[0050] However, if the gas spring 11 and the gas spring 12 are not fixed to the fitting support members 13 and 14, the gas spring 11 and the gas spring 12 may move along the fitting support members 13 and 14 in the left-right direction and come into contact with each other, which may result in damage. Therefore, in this embodiment, as shown in Figures 7(a) and 7(b), the cover-side fitting member 30 is provided with a positioning member 35 for positioning the gas spring 11 and the gas spring 12 at a predetermined position spaced apart from each other by the fitting support member 14 in the left-right direction. After the fitting support member 14 of the gas spring unit 10 is fitted and supported in the U-groove 31 of the cover-side fitting member 30, the positioning member 35 is attached to the cover-side fitting member 30, so that the positioning member 35 enters between the one ends 11B and 12B of the gas springs 11 and 12, and the left-right position is determined by being sandwiched between the fixing ring 15 and the positioning member 35.

[0051] In the above embodiment, the case where the gas spring unit 10 is replaced has been taken as an example. However, the present invention is not limited to this, and can also be applied to the case where the gas spring is used alone.

[0052] In the above-described embodiment, the present invention is applied to the fixing module 4000, but is not limited thereto. The sheet feed module 1000, the drying module 3000, the cooling module 5000, the reversing module 6000, and the stacking module 7000 also have top covers like the fixing module 4000, and may have, for example, a part of a transport unit provided on the top cover. The present invention is also applicable to such sheet feed module 1000, the drying module 3000, the cooling module 5000, the reversing module 6000, and the stacking module 7000. [Explanation of symbols]

[0053] 11...first gas spring, 12...second gas spring, 13, 14...fitting support member (first shaft, second shaft), 13a, 14a...middle portion (step portion), 20...housing side fitting member, 21...recess (U-groove), 23...second regulating portion (rear guide portion), 30...cover side fitting member, 50...cover support member, 60...guide portion, 61...first regulating portion (flat portion, side guide), 400...opening / closing device, 420...housing, 420a...opening, 450...cover (top cover), 2300...image forming portion (recording portion), 4100...conveying portion (fixing belt unit), 4110...first conveying belt (upper belt), 4120...second conveying belt (lower belt)

Claims

1. A housing having an opening on an upper surface thereof; a cover that is provided on the housing so as to be rotatable about a rotation axis along a first direction and that opens and closes the opening; a gas spring unit having a cover side end portion that fits with the cover and a housing side end portion that fits with the housing, the gas spring unit expanding and contracting in accordance with rotation of the cover, The cover side end of the gas spring unit has a cover side shaft extending along the first direction, the cover has a cover-side fitting portion that fits with the cover-side shaft, the cover-side shaft is fitted into the cover-side fitting portion, whereby the gas spring unit supports the cover in a state in which the gas spring unit can rotate about the cover-side shaft relative to the cover, The housing side end of the gas spring has a housing side axis extending in the first direction, the housing has a housing-side fitting portion that fits with the housing-side shaft, the housing-side shaft is fitted into the housing-side fitting portion, whereby the housing supports the gas spring unit in a state in which the gas spring unit can rotate around the housing-side shaft relative to the housing, a housing-side shaft that comes into contact with the housing-side end of the gas spring unit when the gas spring unit is inserted into the housing through the opening, thereby limiting the range of movement of the gas spring unit and guiding the housing-side shaft to a position where the housing-side shaft fits into the housing-side fitting portion; An opening and closing device characterized by the above.

2. the housing side fitting portion has a recess that receives a side surface of the housing side shaft to fit with the housing side shaft, The opening and closing device according to claim 1 .

3. The guide portion is a first restriction portion including two flat plate portions disposed opposite to each other so as to sandwich the housing side shaft in the first direction, the first restriction portion restricting a movement range of the gas spring unit in the first direction by each of the two flat plate portions contacting a tip end surface of the housing side shaft; a second restriction portion that restricts a range of movement of the gas spring unit in the insertion direction by contacting a side surface of the housing side shaft, The housing side shaft slides in a state in which a side surface of the housing side shaft is in contact with the second restriction portion, whereby the housing side shaft is guided. The opening and closing device according to claim 1 .

4. When the cover rotates by a greater amount than a predetermined amount from a state in which the gas spring unit supports the cover, the engagement between the cover-side shaft and the cover-side fitting portion is released. The opening and closing device according to claim 1 .

5. a cover support member that supports the cover in a state in which the cover has been rotated by a greater amount than the predetermined rotation amount; 5. The opening and closing device according to claim 4.

6. The cover-side fitting portion has a recess that fits with the cover-side shaft.

5. The opening and closing device according to claim 4.

7. The gas spring unit includes a first gas spring and a second gas spring that expand and contract in the same direction, The first gas spring and the second gas spring each have a through hole at both ends thereof, the cover-side shaft is inserted through the through hole at one end of the first gas spring and the through hole at one end of the second gas spring; the housing side shaft is inserted through the through hole at the other end of the first gas spring and the through hole at the other end of the second gas spring; The opening and closing device according to claim 1 .

8. Each of the cover-side shaft and the housing-side shaft is provided with an intermediate portion that is disposed between the first gas spring and the second gas spring and has a diameter larger than a diameter of a tip end of each shaft. The opening and closing device according to claim 7 .

9. The gas spring unit is supported removably on the housing. The opening and closing device according to claim 1 .

10. An opening and closing device according to claim 1; An image forming unit that forms an image on a medium.

1. An image forming apparatus comprising:

11. An opening and closing device according to claim 1; a conveying unit that conveys a medium on which an image is to be formed, The conveying unit includes a first conveying belt disposed inside the cover and a second conveying belt disposed inside the housing.

1. An image forming apparatus comprising:

12. a first gas spring that expands and contracts along a first direction; a second gas spring that expands and contracts along the first direction; A first axis extending along a second direction intersecting the first direction; a second axis extending along the second direction, The first gas spring and the second gas spring each have a through hole at both ends thereof, The first shaft is inserted through the through hole at one end of the first gas spring and the through hole at one end of the second gas spring, The second shaft is inserted through the through hole at the other end of the first gas spring and the through hole at the other end of the second gas spring.

1. A gas spring unit for an image forming apparatus.

13. Each of the first shaft and the second shaft has an intermediate portion disposed between the first gas spring and the second gas spring, the intermediate portion having a diameter larger than a diameter of a tip of each shaft.

13. A gas spring unit according to claim 12.

Images