Door latch mechanism and door-equipped device using the same

Abstract

To provide a latch mechanism of an opening / closing door reducing tolerance in a direction of elastic deformation affecting latching force and operating force, compared with a case using an elastically deformable latch member for both of the opening / closing door and a device body.SOLUTION: A latch mechanism of an opening / closing door includes: an elastic component 4 provided on at least one of an opening / closing door 2 and a device body 1 facing an opening, having a spring member 5 that elongates and contracts so as to elastically deform in one direction, and floatably holding both ends of the spring member 5 via a holder 6; and a latch component 7 including a latch member 8 that is provided on the other of the opening door and the device body, when the opening / closing door 2 closes the opening, comes into contact with the holder 6 of the elastic component 4 and in a state where the spring member 5 is elastically deformed from an initial state, constrains the elastic component 4, and when opening the opening / closing door 2 from a closed position, moving the holder 6 against energizing force of the spring member 5 and releasing the constraint state of the elastic component 4 and the latch member 8.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a latch mechanism for an opening / closing door and an apparatus with an opening / closing door using the same. [Background technology]

[0002] As a conventional apparatus with an opening and closing door, for example, an image forming apparatus described in Patent Document 1 is known. Patent document 1 discloses a subunit mounting structure for an image forming device in which a latch mechanism is provided between the subunit and the unit receiving part, in which latch members (made of elastic members) provided on each of the subunit and the unit receiving part are freely engaged and detached to maintain the attached state of the two, and the peak position of the engagement reaction force of the latch mechanism during the subunit attachment operation is displaced forward from the complete engagement position of the latch mechanism (equivalent to the complete attachment position of the subunit), thereby reducing the operating force required to push the subunit into the unit receiving part. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-231322 (Means for Solving the Problem, Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0004] The technical problem that the present invention aims to solve is to reduce the tolerance in the direction of elastic deformation that affects the latch force and operating force in the latch mechanism for the opening and closing door, compared to when elastically deformable latch members are used on both the opening and closing door and the device main body. [Means for solving the problem]

[0005] The invention of claim 1 is a latch mechanism used in an apparatus with an opening / closing door that opens and closes an opening of an apparatus main body with an opening / closing door, which restrains the opening / closing door in a closed position and releases the restrained state when the opening / closing door is opened, characterized in that it comprises: an elastic part that is provided on either the opening / closing door or the apparatus main body facing the opening, and has a spring member that is elastically deformable in a predetermined direction and expands and contracts, and holds both ends of the spring member so that it can float via a holder; and a latch part that is provided on the other of the opening / closing door or the apparatus main body, and comes into contact with the holder of the elastic part when the opening / closing door closes the opening, and has a latch member that restrains the elastic part in a state where the spring member is elastically deformed from its initial state, and when the opening / closing door is opened from the closed position, moves the holder against the spring force of the spring member and releases the restrained state between the elastic part and the latch member.

[0006] The invention according to claim 2 is a latch mechanism for an opening and closing door according to claim 1, wherein the elastic part expands and contracts in the vertical direction. The aforementioned A latch mechanism for opening and closing a door characterized by the use of a spring member. The invention of claim 3 is a latch mechanism for an opening and closing door, characterized in that in the latch mechanism for an opening and closing door of claim 1 or 2, the elastic part forms a guide groove that follows the extension and contraction direction of the spring member relative to the object to be installed, and the holder is slidably held in the guide groove. The invention according to claim 4 is a latch mechanism for an opening and closing door according to claim 1, wherein the latch part clamps and restrains the elastic part. The aforementioned A latch mechanism for an opening and closing door is characterized by having a latch member. The invention of claim 5 is a latch mechanism for an opening and closing door according to claim 4, characterized in that the latch member or the holder has a first guide portion that guides the holder or the latch member so that when the opening and closing door closes the opening, the spring member is gradually compressed and deformed from its initial state until the compression amount of the spring member reaches its peak value, and a second guide portion that guides the holder or the latch member so that, after the compression amount of the spring member has overcome its peak value, the spring member gradually relaxes its compressive deformation from its peak state until it reaches a latch position where the compression amount is a predetermined value less than the peak value. The invention of claim 6 is a latch mechanism for opening and closing doors, characterized in that in the latch mechanism for opening and closing doors of claim 5, the latch member has a pair of latch arms that sandwich the elastic part, and one of the latch arms or holders has a guide surface on one side that is formed in a V shape with the boundary line between the first guide portion and the second guide portion as an inflection point, and the other latch arm or holder has a guide surface on the other side that is formed in a V shape at a wider angle than the guide surface on the one side, with the inflection point being a position past the boundary line between the first guide portion and the second guide portion. The invention according to claim 7 is a latch mechanism for an opening and closing door according to claim 1, wherein the latch part pushes and restrains the elastic part. The aforementioned A latch mechanism for an opening and closing door is characterized by having a latch member. The invention of claim 8 is a latch mechanism for an opening and closing door according to claim 7, characterized in that the latch member or the holder has a first guide portion that guides the holder or the latch member so that when the opening and closing door closes the opening, the spring member is gradually tensilely deformed from its initial state until the amount of tension of the spring member reaches a peak value, and a second guide portion that guides the holder or the latch member so that after the amount of deformation of the spring member has overcome the peak value, the spring member gradually relaxes its tensile deformation from the peak state until the amount of tension reaches a predetermined value that is less than the peak value. The invention of claim 9 is a latch mechanism for opening and closing doors, characterized in that in the latch mechanism for opening and closing doors of claim 8, the latch member has a latch block that pushes apart the elastic part, and the side of the latch block facing one of the holders or one of the holders has a guide surface on one side that is formed in a V shape with the boundary line between the first guide portion and the second guide portion as an inflection point, and the side of the latch block facing the other holder or the other holder has a guide surface on the other side that is formed in a V shape at a wider angle than the guide surface on the one side, with the inflection point being a position past the boundary line between the first guide portion and the second guide portion.

[0007] The invention of claim 10 is a device with an opening and closing door, comprising: a device main body having an opening; an opening and closing door that opens and closes the opening; and a latch mechanism that restrains the opening and closing door in a closed position and releases the restrained state of the opening and closing door when the opening and closing door is opened, wherein the latch mechanism is provided on either the opening and closing door or the device main body facing the opening, has a spring member that expands and contracts elastically in a predetermined direction, and holds both ends of the spring member so that it can float via a holder; and a latch member that is provided on the other of the opening and closing door or the device main body, comes into contact with the holder of the elastic member when the opening and closing door closes the opening, and has a latch member that restrains the elastic member in a state where the spring member is elastically deformed from its initial state, and moves the holder against the biasing force of the spring member when the opening and closing door is opened from the closed position, and releases the restrained state of the elastic member and the latch member. [Effects of the Invention]

[0008] According to the invention of claim 1, the tolerance in the direction of elastic deformation that affects the latch force and operating force of the latch mechanism for the opening and closing door can be reduced compared to when elastically deformable latch members are used on both the opening and closing door and the device main body. According to the invention of claim 2, when the restrained state by the latch mechanism is released, the elastic part can be easily returned to the initial position by its own weight. According to the invention of claim 3, when the elastic part is installed on the installation object, the spring member can be easily maintained in a floating state. According to the invention as defined in claim 4, it is possible to provide a latch mechanism that clamps and restrains the elastic part. According to the invention of claim 5, by devising the shape of the latch member or holder and utilizing the compressive deformation of the spring member, it is possible to provide a latch mechanism that clamps and restrains an elastic part. According to the invention of claim 6, when the door is closed, the retractability of the elastic part by the latch member can be maintained better, and the elastic part can be clamped and restrained. According to the invention as defined in claim 7, it is possible to provide a latch mechanism that stretches and restrains the elastic part. According to the invention of claim 8, by devising the shape of the latch member or the holder and utilizing the tensile deformation of the spring member, it is possible to provide a latch mechanism that spreads and restrains the elastic part. According to the invention of claim 9, when the door is closed, the retractability of the elastic part by the latch member can be maintained better, and the elastic part can be pushed out and restrained. According to the invention of claim 10, it is possible to construct an apparatus with an opening and closing door that includes a latch mechanism for the opening and closing door that can reduce the tolerance in the elastic deformation direction that affects the latch force and operating force, compared to when elastically deformable latch members are used on both the opening and closing door and the apparatus main body. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1(a) is an explanatory diagram showing an overview of an embodiment of a latch mechanism for an opening and closing door to which the present invention is applied and an opening and closing door device using the same; FIG. 1(b) is an explanatory diagram showing a schematic diagram of the behavior of the latch mechanism for an opening and closing door when it starts to latch; and FIG. 1(c) is an explanatory diagram showing a schematic diagram of the behavior of the latch mechanism for an opening and closing door when it has completed latching. [Figure 2] 1 is an external perspective view showing the overall configuration of an image forming apparatus as an apparatus with an opening / closing door according to a first embodiment. [Figure 3]FIG. 2 is an explanatory diagram illustrating an example of an image forming configuration of the image forming apparatus according to the first embodiment. [Figure 4] 1(a) is an explanatory diagram showing the attachment location of the elastic part of the latch mechanism according to embodiment 1, (b) is an explanatory perspective view showing the main part of the elastic part at part B in (a), (c) is a detailed view of part C in (b), and (d) is an arrow view seen from the direction D in (b). [Figure 5] 1A is a perspective explanatory view showing a main part of a latch component of a latch mechanism according to a first embodiment, and FIG. 1B is a view taken along an arrow B in FIG. 1A. [Figure 6] 10 is an explanatory diagram showing a state before the latch mechanism starts to latch before the door is closed in the image forming apparatus according to the first embodiment. FIG. [Figure 7] 10 is an explanatory diagram showing a state in which the latch mechanism is fully latched when the door is closed in the image forming apparatus according to the first embodiment. FIG. [Figure 8] 10A to 10D are explanatory diagrams showing the behavior of the latch mechanism when the door is closed in the image forming apparatus according to the first embodiment, in which (a) shows the state when latching starts, (b) shows the state when the upper inflection point is crossed, (c) shows the state when the lower inflection point is crossed, and (d) shows the state when latching is completed. [Figure 9] (a) to (d) are explanatory diagrams showing the behavior of the latch mechanism when the opening and closing door is closed in the image forming apparatus according to the second embodiment, where (a) is an explanatory diagram showing the state when latching starts, (b) is an explanatory diagram showing the state when the upper inflection point is overcome, (c) is an explanatory diagram showing the state when the lower inflection point is overcome, and (d) is an explanatory diagram showing the state when latching is completed. [Figure 10] (a) to (d) are explanatory diagrams showing the behavior of the latch mechanism when the opening and closing door is closed in the image forming apparatus according to the third embodiment, where (a) is an explanatory diagram showing the state when latching starts, (b) is an explanatory diagram showing the state when the upper inflection point is overcome, (c) is an explanatory diagram showing the state when the lower inflection point is overcome, and (d) is an explanatory diagram showing the state when latching is completed. [Figure 11] 10A to 10D are explanatory diagrams showing the behavior of the latch mechanism when the door is closed in an image forming apparatus according to the fourth embodiment, in which (a) shows the state when latching starts, (b) shows the state when the upper inflection point is crossed, (c) shows the state when the lower inflection point is crossed, and (d) shows the state when latching is completed. DETAILED DESCRIPTION OF THE INVENTION

[0010] Overview of the implementation form FIG. 1(a) shows an outline of an embodiment of a latch mechanism for an opening / closing door to which the present invention is applied and an apparatus with an opening / closing door using the same. In the same figure, the device with an opening / closing door comprises a device main body 1 having an opening not shown, an opening / closing door 2 that opens and closes the opening, and a latch mechanism 3 that restrains the opening / closing door 2 in a closed position and releases the restrained state of the opening / closing door 2 when the opening / closing door 2 is opened. In this example, the latch mechanism 3 is provided on either the opening / closing door 2 or the device main body 1 facing the opening (in this example, the device main body 1), and has a spring member 5 that expands and contracts elastically in a predetermined direction, and is equipped with an elastic part 4 that holds both ends of the spring member 5 so that it can float via holders 6 (specifically 6a, 6b), and a latch part 7 that is provided on the other of the opening / closing door 2 or the device main body 1 (in this example, the opening / closing door 2), and has a latch member 8 that comes into contact with the holders 6 (6a, 6b) of the elastic part 4 when the opening / closing door 2 closes the opening, and restrains the elastic part 4 in a state in which the spring member 5 is elastically deformed from its initial state, and when the opening / closing door 2 is opened from the closed position, moves the holders 6 (6a, 6b) against the biasing force of the spring member 5, and releases the restrained state between the elastic part 4 and the latch member 8. In the embodiment shown in Figure 1(a), the elastic part 4 is installed on the device main body 1 side and the latch part 7 is installed on the opening and closing door 2 side, but it is also possible to reverse the installation positions of the elastic part 4 and the latch part 7.

[0011] In such technical means, the latch mechanism 3 may be configured such that an elastic part 4 is installed on one of the opposing portions of the device main body 1 and the opening / closing door 2, and a latch part 7 is installed on the other, and may be installed in at least one location, but may also be installed in multiple locations. 1(a), for example, the elastic part 4 is installed on the device body 1 side, but since this is an embodiment in which the elastic part 4 is installed on the back side of the device body 1 facing the opening and closing door 2, an insertion opening 1a such as a slit into which the latch member 8 of the latch part 7 provided on the opening and closing door 2 side can be inserted is opened at a position on the device body 1 corresponding to the elastic part 4. However, in an embodiment in which the elastic part 4 is installed on the front side of the device body 1 (corresponding to the opening and closing door 2 side), if the elastic part 4 is installed close to the front side of the device body 1 and the latch member 8 interferes with the device body 1, it is necessary to provide the above-mentioned insertion opening 1a in the device body 1. However, if the elastic part 4 is installed so as to protrude from the front side of the device body 1, for example, the restraining action of the elastic part 4 by the latch member 8 can be performed without providing the above-mentioned insertion opening 1a.

[0012] In this example, the elastic part 4 may be any part in which both ends of a spring member 5 that expands and contracts along a predetermined direction (vertical direction in FIG. 1(a)) are held by holders 6 (6a, 6b). Here, the spring member 5 may be any suitable member, such as a coil spring or a leaf spring, as long as it elastically deforms in a predetermined expansion / contraction direction. Furthermore, the mounting structure for the holder 6 may be any suitable member, as long as it holds the spring member 5 so that it can float. For example, a guide groove 12 extending in the expansion / contraction direction of the spring member 5 may be formed in a mounting member 11 separately mounted to the device body 1, and a sliding portion that can slide along the guide groove 12 may be formed in the holder 6, and the holder 6 may be mounted slidably along the guide groove 12 via the sliding portion. While the holder 6 is mounted on the mounting member 11 in this example, it goes without saying that the mounting portion of the holder 6 may be integrally formed and mounted on a part of the device body 1.

[0013] On the other hand, since the latch member 8 needs to have the function of restraining the spring member 5 of the elastic part 4 by elastically deforming it, any suitable material may be used as long as it has at least the rigidity required to withstand the elastic deformation required by the spring member 5. In the embodiment shown in Figure 1(a), the latch component 7 may be provided on the device main body 1 side of the opening / closing door 2, and may be attached as a separate part from the opening / closing door 2, or the entire latch component 7 may be formed integrally with a part of the opening / closing door 2, or a part of the latch component 7 may be formed integrally with a part of the opening / closing door 2, with the remaining part formed separately. Furthermore, in the embodiment shown in Figure 1(a), the latch part 7 must have at least a latch member 8 that protrudes from the inside of the opening and closing door 2 toward the device body 1 and has a shape that can restrain the elastic part 4. Here, the number and shape of the latch members 8 need only be such that there are latch members 8 that restrain the elastic part 4 by utilizing the elastic deformation of the spring member 5 of the elastic part 4, and the restraining manner may be such that a pair of latch members 8 (specifically 8a, 8b) clamp the holder 6 of the elastic part 4 from the outside, as shown in Figures 1(b) and (c), or such that a single latch member (not shown) pushes the holder 6 of the elastic part 4 apart from the inside. It should be noted that the latch mechanism of Patent Document 1 can be applied to opening and closing doors in place of a subunit, but it is configured to engage and disengage a pair of latch members made of elastic material by elastic deformation, and the mounting tolerances of each latch member accumulate. If this cumulative tolerance becomes large, it will inevitably have a significant effect on the operating force and latching force of the latch mechanism, raising concerns that this may impair the operability of opening and closing doors.

[0014] Next, a representative or preferred embodiment of the latch mechanism 3 in this embodiment will be described. First, a preferred embodiment of the elastic component 4 is one that uses a spring member 5 that expands and contracts in the vertical direction. When the spring member 5 is installed in this manner, the spring member 5 moves downward in the vertical direction under its own weight when the restrained state by the latch mechanism 3 is released, which is preferable in that the elastic component 4 can be easily returned to its initial position under its own weight. Furthermore, a preferred embodiment of the elastic part 4 is one in which a guide groove 12 is formed in the device body 1, which is the object to be installed, along the direction in which the spring member 5 expands and contracts, and the holder 6 is slidably held in the guide groove 12. According to this example, the holder 6 acts as a slider, which is preferable in that the expansion and contraction movement of the spring member 5 is carried out smoothly.

[0015] Furthermore, a representative embodiment of the latch part 7 is one having the latch member 8 that clamps and restrains the elastic part 4, as described above. 1(b)(c), in a preferred embodiment of the present invention, the latch member 8 has a first guide portion 9 that guides the holder 6 so that when the opening / closing door 2 closes the opening, the spring member 5 is gradually compressed and deformed from its initial state until the amount of compression of the spring member 5 reaches its peak value, and a second guide portion 10 that guides the holder 6 so that, after the amount of compression of the spring member 5 has exceeded its peak value, the spring member 5 gradually relaxes its compressive deformation from the peak state until it reaches a latch position where the amount of compression is a predetermined value less than the peak value. In this embodiment, the spring member 5 is compressed and deformed to its peak value, and then its compressed state is relaxed, thereby enabling the latch member 8 to clamp and restrain the elastic part 4. 1(b) and 1(c), the elastic part 4 is depicted by simplifying the shapes of the spring member 5 and the holder 6, and the latch part 7 is depicted by simplifying the shape of the latch member 8.

[0016] A preferred embodiment of this type of first guide portion 9 and second guide portion 10 is one in which the latch member 8 (specifically 8a, 8b) has a pair of latch arms that sandwich the elastic part 4, as shown in Figures 1(b) and (c), and one of the latch arms has a guide surface on one side that is formed in a V shape with the boundary line between the first guide portion 9 and the second guide portion 10 as the inflection point, and the other latch arm has a guide surface on the other side that is formed in a V shape at a wider angle than the guide surface on the one side, with the inflection point being a position past the boundary line between the first guide portion 9 and the second guide portion 10. In this example, the compression of the spring member 5 reaches its peak when it passes through the boundary line P between the first guide portion 9 and the second guide portion 10 (corresponding to the inflection point P1 position of one of the latch arms), and then the compressed state is relaxed.However, when it passes through the inflection point P2 position of the other latch arm, the rate of change in the expansion of the span along the extension direction of the spring member 5 between the second guide portions 10 becomes larger than before the inflection point P2, which makes it easier for the elastic part 4 to be drawn into the second guide portion 10 of the latch part 7, and this is preferable in that the elastic part 4 is smoothly clamped and restrained by the latch part 7. In this example, the first guide portion 9 and the second guide portion 10 are both provided on the latch member 8, but it is also possible to provide them on the holder 6 instead of the latch member 8 and use them to guide the latch member 8.

[0017] Another representative embodiment of the latch part 7 is, as described above, an embodiment having a latch member 8 (different from the embodiment shown in Figures 1(b) and (c)) that pushes open and restrains the elastic part 4. In a preferred embodiment of this example, the latch member 8 may have a first guide portion 9 that guides the holder 6 (6a, 6b) so that when the opening / closing door 2 closes the opening, the spring member 5 is gradually tensilely deformed from the initial state until the amount of tension of the spring member 5 reaches a peak value, and a second guide portion 10 that guides the holder 6 (6a, 6b) so that, after the amount of deformation of the spring member 5 exceeds the peak value, the tensile deformation of the spring member 5 is gradually relaxed from the peak state until the amount of tension reaches a predetermined value that is less than the peak value. In this example, the spring member 5 is tensilely deformed to the peak value and then the tension state is relaxed, allowing the latch member 8 to spread and restrain the elastic part 4.

[0018] A preferred embodiment of this type of first guide portion 9 and second guide portion 10 is one in which, unlike Figures 1(b) and (c), the latch member 8 has a latch block (not shown) that pushes apart the elastic part 4, and the side of the latch block facing one holder 6 (e.g., 6a) has one guide surface that is V-shaped with the boundary line between the first guide portion 9 and the second guide portion 10 as the inflection point, and the side of the latch block facing the other holder 6 (e.g., 6b) has the other guide surface that is V-shaped at a wider angle than the one guide surface with the inflection point being a position past the boundary line between the first guide portion 9 and the second guide portion 10. In this example, the tension of the spring member 5 reaches its peak when it passes the boundary line between the first guide portion 9 and the second guide portion 10 (corresponding to the inflection point position on the side facing one of the holders 6 (e.g., 6a) of the latch block), and then the tension is relaxed.However, when it passes the inflection point position on the side facing the other holder 6 (e.g., 6b) of the latch block, the rate of narrowing of the span along the extension and contraction direction of the spring member 5 between the second guide portions 10 becomes larger than before the inflection point, so that the elastic part 4 is more easily drawn into the second guide portion 10 of the latch part 7, which is preferable in that the latch part 7 smoothly pushes and restrains the elastic part 4. In this example, the first guide portion 9 and the second guide portion 10 are both provided on the latch member 8, but it is also possible to provide them on the holder 6 instead of the latch member 8 and use them to guide the latch member 8.

[0019] The present invention will be described in detail below based on the embodiments shown in the accompanying drawings. Embodiment 1 FIG. 2 is an external perspective view showing the overall configuration of the image forming apparatus, which is an apparatus with an opening / closing door according to the first embodiment. -Overall configuration of image forming device- In the figure, the image forming device 20 has an image creation engine 30 (see FIG. 3) mounted in a device housing 21, a medium supply device 50 for storing media such as paper at the bottom of the device housing 21, and an image reading device 80 at the top of the device housing 21. Reference numeral 81 denotes a document feeder for feeding documents to the image reading device 80. In this example, the device housing 21 has a hollow portion 21a below the image reading device 80 into which media on which images are formed by the image creating engine 30 are discharged and stored, and below that there is space to store the image creating engine 30 etc. In this example, the device housing 21 includes a device main body 22 having an opening 23 on the user operation side (the "front side" in this example) for inserting and removing the image-forming engine 30, etc., and an opening / closing door 25 for opening and closing the opening 23 of the device main body 22.

[0020] Here, the device main body 22 includes a main body frame that frames the shape of the device housing 21, interior materials that are attached to the main body frame and installed inside the device housing 21, and exterior materials that are attached to the main body frame and installed outside the device housing 21. In addition, the opening / closing door 25 is swingably mounted on the lower edge of the opening 23 of the device main body 22 via a hinge not shown, and is capable of swinging open and closed between an open position in which it protrudes in an approximately horizontal position relative to the opening 23 of the device main body 22, and a closed position in which it closes the opening 23. In this example, a latch mechanism 100 is provided between the opening / closing door 25 and the device main body 22 to restrain the opening / closing door 25 in the closed position and to release the restrained state of the opening / closing door 25 when the opening / closing door 25 is opened.

[0021] -Example of image formation configuration of image forming device- <Imaging engine> In this embodiment, the image creation engine 30 is mounted in the device housing 21, as shown in FIG. 3, for example, and forms an image on a medium such as paper, and includes a plurality of (four in this example) image forming units 31 (31a to 31d in this example) that form a plurality of color component images, a belt-like intermediate transfer body 40 that primarily transfers and transports the color component images of each image forming unit 31, a transfer device 60 that collectively transfers the primary transferred image on the intermediate transfer body 40 onto the medium, and a fixing device 70 that fixes the image transferred onto the medium, but of course the invention is not limited to this.

[0022] <Image forming section> In this example, the image forming units 31 are arranged in a substantially horizontal orientation, and each unit forms an image of, for example, four colors (yellow (Y), magenta (M), cyan (C), and black (K)). Each image forming unit 31 (specifically, 31a to 31d) is basically configured to employ, for example, an electrophotographic system, and includes a drum-shaped photosensitive member 32, a charger 33 that charges the photosensitive member 32, a latent image writer 34 that writes an electrostatic latent image on the photosensitive member 32 charged by the charger 33, a developing unit 35 that develops the electrostatic latent image formed by the latent image writer 34 using toner powder (in this example, a two-component developer containing toner and carrier is used), and a cleaner 36 that cleans off residue (mainly residual toner) on the photosensitive member 32 after the toner image formed on the photosensitive member 32 is primarily transferred to the intermediate transfer member 40.

[0023] In this example, the charger 33 may be a charging roll that charges the photosensitive member 32 by contact, or a corotron or scorotron that charges the photosensitive member 32 without contact. Furthermore, in this example, the latent image writer 34 is configured to write separately to each photosensitive member 32 using, for example, an LED array, but this is not limited to this. A shared laser scanner may be provided to write an electrostatic latent image of each color component to each photosensitive member 32 using a corresponding laser beam, or a laser scanner may be provided separately for each photosensitive member 32. Furthermore, the developing device 35 may be one that uses, for example, a two-component developer containing toner and carrier, has a developing roll disposed in a developing container, and has, for example, a plurality of stirring and conveying members disposed in the developing container that charge the developer while stirring and mixing it, but is not limited to this and may be selected as appropriate. Furthermore, as the cleaner 36, a cleaning member such as a cleaning blade, a cleaning brush, or a cleaning roll that scrapes off the toner remaining on the photoreceptor 32 is appropriately selected and used. Incidentally, reference numeral 37 (specifically, 37a to 37d) denotes a toner cartridge that supplies each color component toner to each developing device 35 of each image forming section 31 (31a to 31d).

[0024] <Intermediate transfer body> The intermediate transfer body 40 is provided above the alignment direction of the plurality of image forming units 31 (31a to 31d), and is stretched over a plurality of (four in this example) tension rolls 41 to 44. In this example, the tension roll 41 is used as, for example, a drive roll, the tension roll 42 is used as an opposing roll of the transfer device 60 (transfer roll 61 is used in this example), and the tension roll 43 is used as a tension roll that applies tension to the belt-like intermediate transfer body 40. In addition, a primary transfer device 46 (in this example, a primary transfer roll) is provided on the back surface of the intermediate transfer body 40 facing the photosensitive body 32 of each image forming section 31 (31a to 31d), and a primary transfer bias is applied to the primary transfer device 46 so that the image on the photosensitive body 32 is transferred to the intermediate transfer body 40 side. Furthermore, an intermediate transfer body cleaner 47 is provided at the location where the intermediate transfer body 40 is stretched over the tension roll 41 .

[0025] <Transfer device and fixing device> In this embodiment, the basic configuration of the transfer device 60 is such that a transfer roll 61 is placed opposite the tension roll 42 of the intermediate transfer body 40, and for example, the transfer roll 61 is grounded and a transfer voltage from a transfer power source not shown is applied to the tension roll 42, thereby forming a transfer electric field in the transfer area between the intermediate transfer body 40 and the transfer roll 61, and thereby transferring the image on the intermediate transfer body 40 all at once to paper passing through the transfer area. <Fixing device> In addition, in this embodiment, the fixing device 70 is equipped with a rotatable heating fixing member (in this example, a heating fixing roll is used) 71 whose surface temperature is heated to a predetermined temperature by a heater as a heat source, and a pressure fixing member (in this example, a pressure fixing roll is used) 72 that contacts and rolls with a predetermined contact pressure along the axial direction of the heating fixing member 71, and is configured to fix the unfixed image by passing a medium carrying the unfixed image through the contact area between the two fixing members 71, 72.

[0026] <Media transport system> In this example, the medium supply device 50 has two medium supply units 50a and 50b. The number and layout of the medium supply units may be changed as needed, and a manual medium supply unit may be added as needed. 3, in this example, a medium transport path 51 extending in a substantially vertical direction is provided on the left side of the device housing 21 in the drawing, and the medium supplied from the medium supply device 50 is transported by transport rolls 52, aligned by alignment rolls 53 provided just before the transfer area between the intermediate transfer body 40 and the transfer device 60, and then transported to the transfer area, where the image on the intermediate transfer body 40 is transferred, and then the image is fixed by passing through the transfer area of ​​the fixing device 70. The medium that has been fixed by the fixing device 70 is then received in a medium discharge receiver 56 formed in the hollow portion 21a of the device housing 21 via discharge rolls 55. Furthermore, the design of the media discharge receiver 56 may be modified as appropriate depending on the discharge position of the media, and although the media transport system in this example employs a transport method that forms an image on one side of the media, it is also possible to form an image on both sides of the media by adding, for example, a double-sided transport module.

[0027] -Example of latch mechanism configuration- <Basic configuration example of latch mechanism> In this example, the latch mechanism 100 includes an elastic part 101 on the device body 22 facing the opening / closing door 25, and a latch part 102 on the opening / closing door 25 side, as shown in FIG. In this example, a front upper frame 110 that forms part of the device main body 22 is provided at a location facing the opening 23 of the opening / closing door 25, and this front upper frame 110 has multiple insertion holes 111 for the toner cartridges 37 (37a to 37d) shown in Figure 3, and the elastic part 101 is installed on a side part 112 (see Figure 4(a)) that is shifted to the left side in the figure from the position of the insertion holes 111 of the front upper frame 110.

[0028] -Example of elastic part configuration- In this example, as shown in Figures 4(a) and (b), the elastic part 101 is installed on the front side of the side part 112 of the front upper frame 110, which is part of the device main body 22, and is equipped with an elastically deformable spring member 113 that expands and contracts in the vertical direction, and a pair of holders 120 (specifically 120a, 120b) that hold both ends of the spring member 113. <Spring material> In this example, the spring member 113 is a compression coil spring that applies a biasing force in a tension direction by elastically deforming in a compression direction.

[0029] <Holder> As shown in FIGS. 4(a) to 4(d), the holders 120 (120a, 120b) have the same shape and are arranged symmetrically in the vertical direction. In this example, holder 120 has holder base 121 that receives both ends of spring member 113. This holder base 121 has a rectangular receiving surface 122 with short sides that are approximately the same length as the outer diameter of spring member 113 and long sides that are several times longer than the outer diameter of spring member 113. A guided protrusion 123 that protrudes from receiving surface 122 in a direction away from spring member 113 and has a cross section along the short side direction of receiving surface 122 that is formed into an acute-angled, approximately isosceles triangle shape, and is formed at the tip of the guided protrusion 123 that is sharp and extends in the long side direction of receiving surface 122. A pair of rectangular parallelepiped holder walls 124 are integrally formed on both sides of the long side of the receiving surface 122 of the holder base 121, and recesses 125 for accommodating ends of the spring member 113 are defined between the pair of holder walls 124, with positioning bosses 126 formed at the bottom of these recesses 125 for positioning both ends of the spring member 113. Furthermore, in this example, recessed grooves 127 having a rectangular cross section that extend in the direction of expansion and contraction of the spring member 113 are formed on both outer sides of the long side of the receiving surface 122 of the holder wall 124 of the holder 120, and these recessed grooves 127 are also formed continuing onto the holder base 121 side. Furthermore, a pair of approximately rectangular notches 128 are formed on both sides of the long side of the receiving surface 122 of the guided projections 123 of the holder base 121.

[0030] -Example of elastic part mounting structure- In this example, as shown in FIGS. 4(a) to 4(d), the elastic component 101 is supported on the side portion 112 of the front upper frame 110 via a mounting case 130 so as to be floatable in the vertical direction. Here, the mounting case 130 has a case body 131 that is integrally formed so as to protrude in a box shape from the front side (corresponding to the side facing the opening and closing door 25) of the side part 112 of the front upper frame 110. This case body 131 has a case front wall 133 that protrudes with a predetermined gap between it and the surface of the side part 112 of the front upper frame 110, and this case front wall 133 has a slit-like movement groove 134 with a bottom that extends vertically downward from approximately the center of the upper edge.

[0031] The recessed grooves 127 formed on both sides of the holder 120 (120a, 120b) are fitted into both side edges of this moving groove 134 so as to be able to slide (correspond to sliding movement), and the holder 120 is supported so as to be able to float along the moving groove 134. Furthermore, in this example, stopper stepped portions 135 are formed on both sides of the front wall 133 of the case near the terminal edge of the movement groove 134, and these stopper stepped portions 135 regulate the initial position Q0 of the elastic component 101 when the notch 128 of the lower holder 120b of the elastic component 101 abuts against the stopper stepped portions 135 and the elastic component 101 is not in contact with the latch component 102, that is, when the restrained state by the latch component 102 is released. In this example, when the elastic component 101 is located at the initial position Q0, as shown in FIG. 4(c), a minute gap 136 is secured between the guided protrusion 123 located at the tip of the lower holder 120b of the elastic component 101 and the terminal edge of the movement groove 134.

[0032] In this example, when attaching the elastic part 101 to the mounting case 130, first, a pair of holders 120 (120a, 120b) are temporarily held at both ends of the spring member 113 to assemble the elastic part 101, and then the recessed grooves 127 of the pair of holders 120 (120a, 120b) of the elastic part 101 are fitted into both side edges of the moving groove 134 of the mounting case 130, and the elastic part 101 is allowed to fall under its own weight and stopped at the initial position Q0.

[0033] -Example of latch component configuration- In this embodiment, the latch component 102 is molded integrally with the opening / closing door 25 using a resin material separate from the opening / closing door 25, as shown in FIGS. 2 and 5(a) and (b). In this example, the latch component 102 comprises a base member 140 in the shape of an approximately rectangular plate, which is fixed to a predetermined position inside the opening / closing door 25 via a stopper (not shown), and a latch member 150 which is provided on the base member 140 and which is oriented in the vertical direction when the opening / closing door 25 is in the closed position, and which protrudes toward the elastic component 101 on the device main body 22 side; when the opening / closing door 25 is closed, the latch member 150 clamps and restrains the elastic component 101 from above and below. In this example, the latch member 150 comprises an upper latch arm 151 that protrudes toward the upper holder 120a of the elastic part 101 on the device main body 22 side, and a lower latch arm 152 that is provided below the upper latch arm 151 of the base member 140 and protrudes toward the lower holder 120b of the elastic part 101 on the device main body 22 side. In this example, the resin material used in manufacturing latch component 102 is required to have the function of restraining elastic component 101 while elastically deforming it, so it is preferable that it has at least the rigidity required to withstand the elastic deformation required by spring member 113, and furthermore, it is preferable that the shapes of upper latch arm 151 and lower latch arm 152 are designed to make them less susceptible to elastic deformation.

[0034] <Upper latch arm, lower latch arm> In this example, the upper latch arm 151 and the lower latch arm 152 both protrude with a width dimension narrower than the width dimension of the moving groove 134 of the mounting case 130 of the elastic part 101, but have different cross-sectional shapes. First, the upper latch arm 151 has an arm main body 161 that is trapezoidal in cross section, with the upper side shorter than the lower side when the base member 140 side is the bottom side, and a latch claw portion 162 that protrudes in a V-shaped cross section is formed on the bottom side of this arm main body 161. Therefore, on the bottom surface of the latch claw portion 162, there are inclined portions 163 that are inclined at an angle θ1 with respect to the horizontal direction on the side away from the base member 140 with respect to an upper inflection point (corresponding to the upper vertex) P1 as the boundary, and inclined portions 164 that are inclined at an angle θ2 with respect to the horizontal direction on the side approaching the base member 140 with respect to the upper inflection point P1 as the boundary, and the surfaces of these inclined portions 163, 164 are formed as an upper latch guide surface 165. Further, the lower latch arm 152 has a tongue-shaped arm projection 171 that projects in a direction approximately perpendicular to the base member 140, and on the upper side of this arm projection 171, a horizontal portion 172 is formed on the base member 140 side, and an inclined portion 173 is formed that is inclined at an angle θ3 (in this example, θ2 > θ3) with respect to the horizontal portion 172 and has a sharp tip on the side away from the base member 140. Therefore, on the upper surfaces of the horizontal portion 172 and inclined portion 173 of the arm projection 171, a lower latch guide surface 175 that changes into a V-shape at an angle wider than the upper latch guide surface 165 of the latch claw portion 162 described above is formed.

[0035] Furthermore, in this example, the span between the upper latch arm 151 and the lower latch arm 152 of the latch member 150 changes in accordance with the change between the upper latch guide surface 165 and the lower latch guide surface 175 . Now, as shown in FIG. 5(b), let L1 be the span at the entrance position between the upper latch guide surface 165 and the lower latch guide surface 175, L2 be the span at the position where the upper latch guide surface 165 passes the upper inflection point P1, L3 be the span at the latch position where the elastic part 101 is constrained, and LS0 be the length in the expansion / contraction direction at the initial position Q0 of the elastic part 101. L1>LS0>L3>L2……(I) Meet the following.

[0036] <First guide section, second guide section> In this example, the latch member 150 (specifically, the upper latch arm 151 and the lower latch arm 152) has a first guide portion 181 that guides the pair of holders 120 (120a, 120b) so that when the opening / closing door 25 starts to latch the elastic part 101, the spring member 113 is gradually compressed and deformed from its initial state until the compression amount of the spring member 113 reaches its peak value, and a second guide portion 182 that guides the holders 120 (120a, 120b) so that after the compression amount of the spring member 113 has exceeded its peak value, the spring member 113 gradually relaxes its compressive deformation from the peak state until it reaches a latch position where the compression amount is a predetermined value less than the peak value.

[0037] The first guide portion 181 here refers to the area of ​​the upper latch guide surface 165 corresponding to the inclined portion 163 toward the upper inflection point P1, and the area of ​​the lower latch guide surface 175 corresponding to the inclined portion 163 of the upper latch guide surface 165. In addition, the second guide portion 182 refers to the area of ​​the upper latch guide surface 165 corresponding to the inclined portion 164 past the upper inflection point P1, and the area of ​​the lower latch guide surface 175 corresponding to the inclined portion 164 of the upper latch guide surface 165. In addition, in this example, the upper latch arm 151 has an upper latch guide surface 165 formed in a V-shape with the boundary line P between the first guide portion 181 and the second guide portion 182 as the upper inflection point P1 (corresponding to the upper vertex). In contrast, the lower latch arm 152 has a lower latch guide surface 175 that is V-shaped and has a wider angle than the upper latch guide surface 165, with an inflection point P2 at a position Δd past the boundary line P between the first guide portion 181 and the second guide portion 182.

[0038] - Example of door opening and closing operation - Next, an example of the opening and closing operation of the door 25 in this embodiment will be described. <When closing the door> 2, when the door 25 is closed from the open position, as shown in FIG. 6, when the door 25 is moved toward the closed position, the latch part 102 of the latch mechanism 100 moves toward the elastic part 101 of the device main body 22 (the front upper frame 110 in this example), and the latch members 150 (upper latch arm 151, lower latch arm 152) of the latch part 102 abut against the upper and lower holders 120 (120a, 120b) of the elastic part 101, which is attached to the attachment case 130 so as to sandwich them from above and below, thereby starting the latch operation by the latch part 102. Then, when the door 25 reaches the closed position, the latch part 102 sandwiches and restrains the elastic part 101 while elastically deforming it, as shown in FIG. 7, and the latch operation of the elastic part 101 by the latch part 102 is completed.

[0039] <Latch mechanism behavior when closing the door> The behavior of the latch mechanism 100 accompanying the opening and closing operation of the opening and closing door 25 will be described in detail with reference to FIGS. 4, 5 and 8(a) to 8(d). In Figures 8(a) to (d), the elastic part 101 is represented by simplifying the shapes of the spring member 113 and the holder 120 (120a, 120b), and the latch part 102 is represented by simplifying the shapes of the latch member 150 (upper latch arm 151, lower latch arm 152). Now, when the opening / closing door 25 moves toward the closed position and the latch part 102 starts to latch the elastic part 101, as shown in Fig. 8(a), the latch members 150 (upper latch arm 151, lower latch arm 152) pinch the tips of the upper and lower holders 120 (120a, 120b) of the elastic part 101 located at the initial position Q0, causing the elastic part 101 to float along the moving groove 134. At this time, the holders 120 (120a, 120b) of the elastic part 101 come into contact with the first guide part 181 of the latch member 150, with the spring member 113 of the elastic part 101 maintaining the free length before compression deformation.

[0040] Thereafter, when the opening / closing door 25 is further moved toward the closed position, the holder 120 of the elastic part 101 is guided along the first guide portion 181 toward the upper inflection point P1, and the span between the pair of holders 120 is gradually narrowed by the first guide portion 181, so that the spring member 113 held by the holder 120 is gradually compressed and deformed from its initial state. Then, as shown in FIG. 8(b), when the holders 120 of the elastic element 101 reach the upper inflection point P1, the span between the pair of holders 120 becomes minimum, and the compression amount of the spring member 113 reaches its peak value. Thereafter, when the opening / closing door 25 is further moved toward the closed position, the holder 120 of the elastic part 101 is guided along the second guide portion 182, and when it reaches the second guide portion 182, the span between the pair of holders 120 gradually expands from the minimum span L2, and the compression amount of the spring member 113 held by the holder 120 is gradually relaxed from the peak value.

[0041] 8(c), the holders 120 of the elastic element 101 pass through the lower inflection point P2. At this time, the rate of change in the expansion of the span between the holders 120 of the elastic element 101 positioned between the second guide portions 182 is greater after the lower inflection point P2 than before the lower inflection point P2, so the elastic element 101 is more likely to be drawn into the second guide portions 182. Then, when the opening / closing door 25 reaches the closed position, as shown in Figure 8(d), the elastic part 101 reaches the latch position P3, which is past the lower inflection point P2, and the spring member 113 of the elastic part 101 is held at the latch position P3 of the second guide part 182 while maintaining a compression amount of a predetermined value that is less than the peak value. In this state, the latch member 150 (upper latch arm 151, lower latch arm 152) clamps and restrains the elastic part 101 while keeping it compressed and deformed, and the latching operation of the elastic part 101 by the latch part 102 is completed.

[0042] In this case, since the latch position P3 of the elastic part 101 by the latch part 102 is determined depending on the installation accuracy of the latch part 102, it is only necessary to appropriately select the installation position of the latch part 102 so that the latch force and operating force of the latch mechanism 100 are appropriate. In this way, in this example, the elastic part 101 is provided on the device main body 22 side, and the latch part 102 is provided on the opening / closing door 25 side, but since the elastic part 101 is provided so that it can float relative to the device main body 22, even if there is an installation error in the elastic part 101, the installation error is absorbed in the direction of expansion and contraction of the elastic part 101, so the tolerance between the elastic part 101 and the latch part 102 does not increase cumulatively, and the latch force and operating force of the latch mechanism 100 are determined by the installation accuracy of the latch part 102.

[0043] <When opening the door> Conversely, when opening the opening / closing door 25 that is in the closed position, as shown in Figure 7, when an attempt is made to open the opening / closing door 25 from the closed position, the latch part 102 of the latch mechanism 100 moves in a direction away from the elastic part 101 of the device main body 22, and as shown in Figure 6, the restraint state of the elastic part 101 by the latch part 102 is released, the latch part 102 completes the unlatching operation of the elastic part 101, and the opening / closing door 25 is opened to the open position shown in Figure 2.

[0044] <Latch mechanism behavior when opening the door> At this time, when the opening / closing door 25 is in the closed position, the latch part 102 is restrained by clamping the elastic part 101 in a compressed and deformed state at a predetermined latch position P3, as shown in Figure 8(d). In this state, when opening the opening / closing door 25 from the closed position, an operating force for opening the opening / closing door 25 is applied against the latching force of the latch mechanism 100 at the latch position P3 (corresponding to the spring force of the spring member 113 at the latch position P3). However, since it is easy to appropriately select the latching force of the latch mechanism 100 at the latch position P3, there is no concern that the operating force for opening the opening / closing door 25 will be unnecessarily large. When the opening and closing door 25 is opened in this manner, the latch mechanism 100 can release the latched state of the elastic part 101 by passing through the states of Figure 8(d) → Figure 8(c) → Figure 8(b) → Figure 8(a).

[0045] Embodiment 2 -Example of latch mechanism configuration- 9(a) to 9(d) are explanatory views showing the main parts of a latch mechanism according to the second embodiment. In this embodiment, the latch mechanism 100 differs from embodiment 1 in that an elastic part 101 is provided on the opening / closing door 25 (see Figure 2) side, and a latch part 102 is provided on the device main body 22 (see Figure 2) side. In this example, the elastic part 101 has both ends of a spring member 113 held by a pair of holders 120 (120a, 120b), and the holders 120 are supported so as to be able to float in the extension / contraction direction of the spring member 113 relative to the opening / closing door 25 using a method substantially similar to that of embodiment 1. In particular, in this example, unlike embodiment 1, of the holders 120 (120a, 120b) of the elastic part 101, an upper latch guide surface 265 that changes into a V-shape at an upper inflection point P1 is formed on the upper side of the upper holder 120a, and a lower latch guide surface 275 that changes into a V-shape at a wider angle than the upper latch guide surface 265 is formed on the lower side of the lower holder 120b, at a lower inflection point P2.

[0046] Furthermore, the latch component 102 has a latch member 150 (upper latch arm 151, lower latch arm 152) integrally provided on the base member 140, with the upper latch arm 151 having an arm projection 191 that projects in a direction substantially perpendicular to the base member 140, and the arm projection 191 has a latch claw 192 formed at its tip with an isosceles triangular cross section and a sharpened tip on the lower side. On the other hand, the lower latch arm 152 is provided symmetrically to the upper latch arm 151, and has an arm projection 201 that projects in a direction substantially perpendicular to the base member 140, and the arm projection 201 has a latch claw 202 formed at its tip with an isosceles triangular cross section and a sharpened tip on the upper side.

[0047] Furthermore, in this example, when the opening / closing door 25 closes the opening 23, the holder 120 (upper holder 120a, lower holder 120b) has a first guide portion 281 that guides the latch member 150 (upper latch arm 151, lower latch arm 152) so that after the elastic part 101 starts to latch, the spring member 113 is gradually compressed and deformed from its initial state to bring the compression amount of the spring member 113 to its peak value, and a second guide portion 282 that guides the latch member 150 (upper latch arm 151, lower latch arm 152) so that after the compression amount of the spring member 113 has exceeded its peak value, the spring member 113 gradually relaxes its compressive deformation from the peak state to reach a latch position P3 where the compression amount is a predetermined value less than the peak value.

[0048] The first guide portion 281 here refers to the area of ​​the upper latch guide surface 265 corresponding to the inclined portion 263 toward the upper inflection point P1, and the area of ​​the lower latch guide surface 275 corresponding to the inclined portion 263 of the upper latch guide surface 265. In addition, the second guide portion 282 refers to the area of ​​the upper latch guide surface 265 corresponding to the inclined portion 264 past the upper inflection point P1, and the area of ​​the lower latch guide surface 275 corresponding to the inclined portion 264 of the upper latch guide surface 265. In addition, in this example, the upper holder 120a has an upper latch guide surface 265 formed in a V-shape with the boundary line P between the first guide portion 281 and the second guide portion 282 as the upper inflection point P1 (corresponding to the upper vertex). In contrast, the lower holder 120b has a lower latch guide surface 275 that is V-shaped and has a wider angle than the upper latch guide surface 265, with the lower inflection point P2 located slightly past the boundary line P between the first guide portion 281 and the second guide portion 282.

[0049] -Latch mechanism behavior- According to the latch mechanism 100 of this embodiment, when the opening / closing door 25 is to be closed from the open position, the elastic part 101 on the opening / closing door 25 side moves toward the latch part 102 on the device main body 22 side, and as shown in FIG. 9(a), the latch claws 192, 202 of the latch member 150 (upper latch arm 151, lower latch arm 152) abut against the first guide part 281 of the holder 120 (upper holder 120a, lower holder 120b) of the elastic part 101. Furthermore, when the opening / closing door 25 is moved in the closing direction, the latch claws 192, 202 of the latch member 150 (upper latch arm 151, lower latch arm 152) are guided along the first guide part 281 toward the upper inflection point P1, and the holder 120 (upper holder 120a, lower holder 120b) of the elastic part 101 is pushed in the approaching direction. Therefore, the span between the pair of holders 120 is gradually narrowed by the first guide portion 281, and the spring members 113 held by the holders 120 are gradually compressed and deformed from the initial state. Then, as shown in FIG. 9(b), when the holders 120 of the elastic element 101 reach the upper inflection point P1, the span between the pair of holders 120 becomes minimum, and the compression amount of the spring member 113 reaches its peak value. Thereafter, when the opening / closing door 25 is further moved toward the closed position, the latch claw portions 192, 202 of the latch member 150 (upper latch arm 151, lower latch arm 152) are guided along the second guide portion 282, and when they reach the second guide portion 282, the span between the pair of holders 120 gradually expands from the minimum span L2, and the compression amount of the spring member 113 held by the holder 120 is gradually relaxed from the peak value.

[0050] 9(c), the holders 120 of the elastic element 101 pass through the lower inflection point P2. At this time, the rate of change in the expansion of the span between the holders 120 of the elastic element 101 positioned between the second guide portions 282 is greater after the lower inflection point P2 than before the lower inflection point P2, so the elastic element 101 is more likely to be drawn into the second guide portions 282. Then, when the opening / closing door 25 reaches the closed position, as shown in Figure 9(d), the latch claw portions 192, 202 of the latch member 150 (upper latch arm 151, lower latch arm 152) reach the latch position P3, which is past the lower inflection point P2, and the spring member 113 of the elastic part 101 is held at the latch position P3 of the second guide portion 282 while maintaining a compression amount of a predetermined value that is less than the peak value. In this state, the latch member 150 (upper latch arm 151, lower latch arm 152) clamps and restrains the elastic part 101 while keeping it compressed and deformed, and the latching operation of the elastic part 101 by the latch part 102 is completed. Furthermore, when the opening and closing door 25 is opened from the closed position, the latch mechanism 100 can release the latched state of the elastic part 101 by passing through the states of Figure 9(d) → Figure 9(c) → Figure 9(b) → Figure 9(a).

[0051] Embodiment 3 10(a) to 10(d) are explanatory views showing the main parts of a latch mechanism according to the third embodiment. In this embodiment, the latch mechanism 100 is similar to the first embodiment in that an elastic part 101 is provided on the device main body 22 (see FIG. 2) side and a latch part 102 is provided on the opening / closing door 25 (see FIG. 2) side, but unlike the first and second embodiments, the latch part 102 pushes and restrains the elastic part 101. In this example, the basic configuration of elastic element 101 is substantially the same as in embodiment 1, but unlike embodiment 1, spring member 114 uses a tension coil spring that applies a biasing force in a compression direction by elastically deforming in a tension direction. Furthermore, holder 120 (120a, 120b) that holds both ends of spring member 114 differs from embodiment 1 in that guided protrusions 123 having a protruding shape (for example, an isosceles triangular cross section) are arranged to face each other, and part of guided protrusions 123 has a structure (for example, a recess) that allows the end of spring member 114 to be hooked.

[0052] Furthermore, the latch component 102 is, for example, a latch member 150 formed integrally on the inside of the opening / closing door 25. In this example, the latch member 150 has one latch block 153, and has an upper latch guide surface 365 that protrudes upward on an upper side facing the upper holder 120a of the latch block 153 and is formed in a V-shape with an upper inflection point P1 as the boundary, and a lower latch guide surface 375 that is formed in a V-shape with a wider angle than the upper latch guide surface 365 on a lower side facing the lower holder 120b of the latch block 153 and is formed in a V-shape with a lower inflection point P2 as the boundary. Furthermore, in this example, the latch block 153 has a first guide portion 381 that guides the holder 120 (upper holder 120a, lower holder 120b) so that when the opening / closing door 25 is closed, the spring member 114 is gradually tensilely deformed from its initial state until the tensile amount of the spring member 114 reaches its peak value, and a second guide portion 382 that guides the holder 120 (upper holder 120a, lower holder 120b) to a latch position P3 where the tensile deformation of the spring member 114 is gradually relaxed from the peak state after the tensile amount of the spring member 114 has exceeded its peak value, and the tensile amount reaches a predetermined value that is less than the peak value. In this example, the upper inflection point P1 and the lower inflection point P2 may coincide with each other, but the lower inflection point P2 is positioned slightly shifted toward the second guide portion 382 from the upper inflection point P1.

[0053] -Latch mechanism behavior- According to the latch mechanism 100 of this embodiment, when the opening / closing door 25 is to be closed from the open position, the latch member 150 (in this example, the latch block 153 is used) of the latch part 102 on the opening / closing door 25 side moves toward the elastic part 101 on the device main body 22 side, and as shown in FIG. 10(a), the holder 120 (upper holder 120a, lower holder 120b) of the elastic part 101 abuts against the first guide portion 381 of the latch member 150 (latch block 153) of the latch part 102. When the opening / closing door 25 is further moved in the closing direction, the holder 120 (upper holder 120a, lower holder 120b) of the elastic part 101 is guided along the first guide portion 381 toward the upper inflection point P1, and the holders 120 (upper holder 120a, lower holder 120b) of the elastic part 101 are pushed apart in the direction of moving away from each other. Therefore, the span between the pair of holders 120 is gradually widened by the first guide portion 381, and the spring member 114 held by the holders 120 is gradually tensile-deformed from the initial state. Then, as shown in FIG. 10(b), when the holders 120 of the elastic element 101 reach the upper inflection point P1, the span between the pair of holders 120 becomes maximum, and the tension of the spring member 114 reaches its peak value. Thereafter, when the opening / closing door 25 is further moved toward the closed position, the holder 120 of the elastic part 101 is guided along the second guide portion 382, ​​and when it reaches the second guide portion 382, ​​the span between the pair of holders 120 is gradually narrowed from the maximum span, and the tension of the spring member 114 held by the holder 120 is gradually relaxed from the peak value.

[0054] 10(c), the holders 120 of the elastic element 101 pass through the lower inflection point P2. At this time, the rate of narrowing of the span between the holders 120 of the elastic element 101 positioned between the second guide portions 382 is greater after the lower inflection point P2 than before the lower inflection point P2, so the elastic element 101 is more likely to be drawn into the second guide portions 382. Then, when the opening / closing door 25 reaches the closed position, as shown in Figure 10(d), the holder 120 of the elastic part 101 reaches the latch position P3, which is past the lower inflection point P2, and the spring member 114 of the elastic part 101 is held at the latch position P3 of the second guide part 382 while maintaining a tension amount of a predetermined value that is less than the peak value. In this state, the latch member 150 (latch block 153) spreads and restrains the elastic part 101 while keeping it tensile-deformed, and therefore the latching operation of the elastic part 101 by the latch part 102 is completed. Furthermore, when the opening and closing door 25 is opened from the closed position, the latch mechanism 100 can release the latched state of the elastic part 101 by passing through the states of Figure 10(d) → Figure 10(c) → Figure 10(b) → Figure 10(a).

[0055] Embodiment 4 11(a) to 11(d) are explanatory views showing the main parts of a latch mechanism according to the fourth embodiment. In this embodiment, the latch mechanism 100 is similar to the second embodiment in that an elastic part 101 is provided on the opening / closing door 25 (see FIG. 2) side and a latch part 102 is provided on the device main body 22 (see FIG. 2) side, but unlike the first and second embodiments, the latch part 102 pushes and restrains the elastic part 101. In this example, the basic configuration of elastic element 101 is substantially the same as in embodiment 1, but unlike embodiment 1, spring member 114 uses a tension coil spring that applies a biasing force in a compression direction by elastically deforming in a tension direction. Furthermore, holder 120 that holds both ends of spring member 114 is substantially the same as in embodiment 2, but unlike embodiment 2, upper holder 120a is formed on the lower side with upper inflection point P1 as the boundary and upper latch guide surface 465 that protrudes and changes in a V-shape, and lower holder 120b is formed on the upper side with lower inflection point P2 as the boundary and lower latch guide surface 475 that changes in a V-shape at a wider angle than upper latch guide surface 465.

[0056] Furthermore, unlike embodiment 2, latch component 102 uses a rod-shaped latch block 154 extending in the vertical direction as latch member 150, and latch claw portions 155, 156 having a cross section of an approximately isosceles triangle shape with sharp tips are formed at the upper and lower ends of this latch block 154. Furthermore, in this example, when the opening / closing door 25 closes the opening 23, the holder 120 (upper holder 120a, lower holder 120b) has a first guide portion 481 that guides the latch member 150 (latch block 154) so ​​that, after the elastic part 101 starts to latch, the spring member 114 is gradually tensilely deformed from the initial state to bring the tensile amount of the spring member 114 to a peak value, and a second guide portion 482 that guides the latch member 150 (latch block 154) so ​​that, after the tensile amount of the spring member 114 has exceeded the peak value, the tensile deformation of the spring member 114 is gradually relaxed from the peak state to reach a latch position P3 where the tensile amount is a predetermined value less than the peak value. In this example, the upper inflection point P1 and the lower inflection point P2 may coincide with each other, but the lower inflection point P2 is positioned slightly shifted toward the second guide portion 482 from the upper inflection point P1.

[0057] -Latch mechanism behavior- According to the latch mechanism 100 of this embodiment, when the opening / closing door 25 is to be closed from the open position, the elastic part 101 on the opening / closing door 25 side moves toward the latch part 102 on the device main body 22 side, and as shown in FIG. 11(a), the latch claws 155, 156 of the latch member 150 (latch block 154) abut against the first guide part 481 of the holder 120 (upper holder 120a, lower holder 120b) of the elastic part 101. When the opening / closing door 25 is further moved in the closing direction, the latch claws 155, 156 of the latch member 150 (latch block 154) are guided along the first guide part 481 toward the upper inflection point P1, and the holders 120 (upper holder 120a, lower holder 120b) of the elastic part 101 are pushed apart in the direction of moving away from each other. Therefore, the span between the pair of holders 120 is gradually widened by the first guide portion 481, and the spring members 114 held by the holders 120 are gradually tensilely deformed from the initial state. Then, as shown in FIG. 11(b), when the holders 120 of the elastic element 101 reach the upper inflection point P1, the span between the pair of holders 120 becomes maximum, and the tension of the spring member 114 reaches its peak value. Thereafter, when the opening / closing door 25 is further moved toward the closed position, the latch claws 155, 156 of the latch member 150 (latch block 154) are guided along the second guide portion 482, and when they reach the second guide portion 482, the span between the pair of holders 120 is gradually narrowed from the maximum span, and the tension of the spring member 114 held by the holder 120 is gradually relaxed from the peak value.

[0058] In particular, in this example as well, the latch claws 155, 156 of the latch member 150 (latch block 154) pass through the lower inflection point P2 as shown in Figure 11(c) . At this time, the rate of change in the expansion of the span between the holders 120 of the elastic element 101 located between the second guide portions 482 is greater after the lower inflection point P2 than before. This makes it easier for the latch member 150 (latch block 154) to be drawn into the second guide portions 482. Then, when the opening / closing door 25 reaches the closed position, as shown in Figure 11(d), the latch claw portions 155, 156 of the latch member 150 (latch block 154) reach the latch position P3, which is past the lower inflection point P2, and the spring member 114 of the elastic part 101 is held at the latch position P3 of the second guide portion 482 while maintaining a tension amount of a predetermined value that is less than the peak value. In this state, the latch member 150 (latch block 154) spreads and constrains the elastic part 101 while keeping it tensile-deformed, and therefore the latching action of the elastic part 101 by the latch part 102 is completed. Furthermore, when the opening and closing door 25 is opened from the closed position, the latch mechanism 100 can release the latched state of the elastic part 101 by passing through the states of Figure 11(d) → Figure 11(c) → Figure 11(b) → Figure 11(a). [Explanation of symbols]

[0059] 1...device body, 1a...insertion opening, 2...opening / closing door, 3...latch mechanism, 4...elastic part, 5...spring member, 6 (6a, 6b)...holder, 7...latch part, 8 (8a, 8b)...latch member, 9...first guide portion, 10...second guide portion, 11...mounting member, 12...guide groove

Claims

1. A latch mechanism used in an apparatus with an opening / closing door that opens and closes an opening of an apparatus body with the opening / closing door, which restrains the opening / closing door in a closed position and releases the restrained state when the opening / closing door is opened, an elastic component provided on either the opening / closing door or the device body facing the opening, the elastic component having a spring member that expands and contracts elastically in a predetermined direction, and that floatably holds both ends of the spring member via a holder; a latch member that is provided on either the opening / closing door or the device main body and that comes into contact with the holder of the elastic element when the opening / closing door closes the opening, and that restrains the elastic element in a state in which the spring member is elastically deformed from its initial state, and that moves the holder against the biasing force of the spring member when the opening / closing door is opened from its closed position, thereby releasing the restrained state between the elastic element and the latch member; A latch mechanism for an opening and closing door, comprising:

2. 2. The latch mechanism for an opening and closing door according to claim 1, A latch mechanism for an opening and closing door, characterized in that the elastic part uses a spring member that expands and contracts in the vertical direction.

3. The latch mechanism for an opening and closing door according to claim 1 or 2, A latch mechanism for an opening and closing door, characterized in that the elastic part has a guide groove formed in the installation object in the direction of expansion and contraction of the spring member, and the holder is slidably held in the guide groove.

4. 2. The latch mechanism for an opening and closing door according to claim 1, A latch mechanism for an opening and closing door, characterized in that the latch part has the latch member that clamps and restrains the elastic part.

5. 5. The latch mechanism for an opening and closing door according to claim 4, a latch mechanism for an opening and closing door, characterized in that the latch member or the holder has a first guide portion that guides the holder or the latch member so that when the opening and closing door closes the opening, the spring member is gradually compressed and deformed from its initial state until the compression amount of the spring member reaches its peak value, and a second guide portion that guides the holder or the latch member so that, after the compression amount of the spring member has overcome its peak value, the spring member gradually relaxes its compressive deformation from the peak state until it reaches a latch position where the compression amount is a predetermined value less than the peak value.

6. 6. The latch mechanism for an opening and closing door according to claim 5, The latch member has a pair of latch arms that sandwich the elastic part, and one of the latch arms or holders has a guide surface on one side that is formed in a V shape with the boundary line between the first guide portion and the second guide portion as the inflection point, and the other latch arm or holder has a guide surface on the other side that is formed in a V shape at a wider angle than the guide surface on the one side with the inflection point being a position past the boundary line between the first guide portion and the second guide portion.A latch mechanism for opening and closing doors, characterized in that

7. 2. The latch mechanism for an opening and closing door according to claim 1, A latch mechanism for an opening and closing door, characterized in that the latch part has the latch member that pushes the elastic part apart and restrains it.

8. The latch mechanism for an opening and closing door according to claim 7, a latch mechanism for an opening and closing door, the latch member or the holder having a first guide portion that guides the holder or the latch member so that when the opening and closing door closes the opening, the spring member is gradually tensile-deformed from its initial state until the amount of tension of the spring member reaches a peak value, and a second guide portion that guides the holder or the latch member so that, after the amount of deformation of the spring member has overcome the peak value, the spring member gradually relaxes its tensile deformation from the peak state until the amount of tension reaches a predetermined value that is less than the peak value.

9. The latch mechanism for an opening and closing door according to claim 8, The latch member has a latch block that pushes apart the elastic part, and the side of the latch block facing one of the holders or one of the holders has a guide surface on one side that is formed in a V-shape with the boundary line between the first guide portion and the second guide portion as the inflection point, and the side of the latch block facing the other holder or the other holder has a guide surface on the other side that is formed in a V-shape at a wider angle than the guide surface on the one side, with the inflection point being a position past the boundary line between the first guide portion and the second guide portion.A latch mechanism for opening and closing doors, characterized in that

10. a device body having an opening; an opening / closing door that opens and closes the opening; a latch mechanism that restrains the door at a closed position and releases the restrained state of the door when the door is opened; Equipped with the latch mechanism is provided on either the door or the device body facing the opening, and has a spring member that expands and contracts elastically in a predetermined direction, and an elastic part that holds both ends of the spring member via a holder so that the spring member can float; a latch member that is provided on either the opening / closing door or the device main body and that comes into contact with the holder of the elastic element when the opening / closing door closes the opening, and that restrains the elastic element in a state in which the spring member is elastically deformed from its initial state, and that moves the holder against the biasing force of the spring member when the opening / closing door is opened from its closed position, thereby releasing the restrained state between the elastic element and the latch member; A device with an opening and closing door, comprising:

Images