JP2006208910A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that deters a unit (scanner section) from vigorously opening and then deters the unit etc., from being broken, without forcing the user to follow troublesome operation procedures or increasing the cost of the apparatus. <P>SOLUTION: As representative constitution, this image forming apparatus has a printer section 2, having an image forming portion which forms an image on a recording material and the scanner section 1, fitted to the printer section 2 in an openable/closable state and is provided with a pop-up spring 34, between the printer section 2 and the scanner section 1, which energizes the scanner section 1 in an opening direction and a scissor screen unit 100, which brakes the movement of the scanner section 1 in the opening direction, when a manual energizing force to the scanner section 1 in the opening direction disappears, while allowing the scanner section 1 to be moved manually in the opening direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus in which a scanner unit is installed to be openable and closable with respect to a printer unit.

  In recent years, in an image forming apparatus as a multifunction peripheral (MFP) having functions as a facsimile, a copier, and a printer, as shown in FIGS. Things are becoming mainstream. In such an image forming apparatus, a recording material P after image formation is ejected and stacked 3 formed between a scanner unit 1 as a document reading unit and a printer unit 2 as an image forming unit provided therebelow. Discharge and load.

  As such an image forming apparatus, there is an image forming apparatus that opens and closes as a maintenance cover 14 on the upper surface side of the casing of the printer unit 2 as shown in FIGS. Alternatively, in some cases, the scanner unit 1 opens and closes with respect to the printer unit 2 so that the discharged recording material P can be easily taken out.

  Such an image forming apparatus records in a discharge tray portion that includes a printer portion exterior top (top cover) 16 that constitutes the exterior of the printer portion 1 and a maintenance cover 14 that opens and closes for cartridge replacement and jam processing. The material P is discharged and loaded.

  Such an image forming apparatus has a document placement surface on which a document is placed. A document presser 4 for pressing and holding the document on the document placement surface is supported by the scanner unit 1 so as to be opened and closed in the same direction as the scanner unit 1.

  Further, an automatic document feeding means for conveying the documents stacked on the document stacking tray 6 U-turns one by one and reading the document by the scanner unit 1 and then guiding it to the document discharge tray 27 (also serving as the upper surface of the document retainer 4). There is also an image forming apparatus having (ADF) 5.

  The hinge unit 15 of the scanner unit 1 and the hinge unit 19 of the document holder 4 are disclosed in Patent Document 1 (Patent No. 3318098), Patent Document 2 (JP-A-8-101466), and Patent Document 3 (JP-A 2002-365743). As described above, a mechanism for balancing the weight using a compression spring and a cam is generally provided. The opening and closing operations of the scanner unit 1 and the document presser 4 are assisted with a light force and the weight is balanced so that a free stop is possible.

  However, in the image forming apparatus in which the document retainer 4 is provided in the scanner unit 1 and the scanner unit 1 and the document retainer 4 are provided to be openable and closable in the same direction, the center of gravity position G1 in a state where the document retainer 4 is closed and the opened state. The center of gravity position G2 is greatly different.

  The original presser 4 that is in a normal use state is set in a closed state so that the weight balance can be achieved. Therefore, when the document retainer 4 is closed (the state shown in FIG. 20), the weight balance is maintained at the hinge portion 15 even if the lock release button 20a is released. It does not open like the state of 21.

  However, as shown in FIGS. 22 and 23, when the scanner unit 1 is opened by releasing the lock release button 20a with the document presser 4 opened (the state shown in FIG. 22), the center of gravity is located at the rear side. G2 further moves, and finally moves backward from the hinge portion 15. Therefore, at this time, the opening speed of the scanner unit 1 is accelerated, and the scanner unit 1 opens with a great force.

  Further, as shown in FIG. 19, when the lock release button 20a is released, the scanner unit 1 is slightly popped up and opened by the urging force of the pop-up spring 34 so that the scanner unit 1 can be easily opened.

  The pop-up spring 34 acts moderately when the document presser 4 is closed. However, when the document retainer 4 is opened, there is a risk that the scanner unit 1 will open backward vigorously from the moment the lock release button 20a is released. Further, there is a risk that the scanner unit 1 itself, the document pressing unit 4, the automatic document feeding means (ADF) 5, and the hinge unit 15 may be damaged by the impact that the scanner unit 1 that has been vigorously opened suddenly stops.

  In addition, when the printer unit 1 is smaller and lighter than the scanner unit 1, there is a risk that the apparatus itself falls. In particular, in an apparatus provided with an automatic document feeder (ADF) 5, the center of gravity is further rearward by the weight of the ADF 5, and the risk of the apparatus falling over increases.

  In order to solve such a problem, as shown in Patent Document 4 (Japanese Patent Laid-Open No. 2001-022143), in addition to the locking mechanism of the scanner unit and the printer unit, a locking mechanism is also provided in the document pressing unit and the scanner unit. Things have been devised. The scanner unit can be opened with respect to the printer unit only when the document pressing unit and the scanner unit are locked.

Japanese Patent No. 3318098 JP-A-8-101466 JP 2002-365743 JP2001-022143

  However, the image forming apparatus described in Patent Document 1 requires a confusing operation procedure for the user, and requires a space for the lock mechanism itself in each of the scanner unit and the document holding unit, which increases the size and cost of the apparatus. There was a problem of being connected to. Moreover, the danger when the locking mechanism does not operate reliably increases.

  Therefore, the present invention suppresses the unit (scanner unit) from opening vigorously and prevents the unit from being damaged without forcing the user to perform misleading operation procedures, increasing the size and cost of the apparatus. An object of the present invention is to provide an image forming apparatus capable of performing the above.

  In order to solve the above-described problems, a typical configuration of an image forming apparatus according to the present invention includes an apparatus main body having an image forming unit for forming an image on a recording material, and an openable and closable attachment to the apparatus main body. In an image forming apparatus having a unit, an urging mechanism that urges the unit in a direction to open the unit and a manual movement of the unit in the opening direction are permitted between the apparatus main body and the unit. And a braking mechanism that brakes the movement of the unit in the opening direction when the manually biasing force in the opening direction is lost.

  As described above, according to the present invention, it is possible to prevent the unit (scanner unit) from opening vigorously without compromising the user's confusing operation procedure or increasing the size and cost of the device, and the unit is damaged. Can be suppressed.

[First embodiment]
A first embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings. 1 and 2 are perspective views of the image forming apparatus as viewed from the front right side of the apparatus according to the present embodiment. FIG. 1 is a view showing a state in which the scanner unit 1 is opened with the document presser 4 closed. FIG. 2 is a view showing a state in which the scanner unit 1 is opened with the document retainer 4 opened. FIG. 3 is a configuration diagram of the image forming apparatus in a state where both the document presser 4 and the scanner unit 1 are closed with respect to the printer unit 2. 4 is a main longitudinal sectional view of the image forming apparatus in the state of FIG. FIG. 5 is a configuration diagram of the image forming apparatus in a state where only the document presser 4 is opened. FIG. 6 is a configuration diagram of the image forming apparatus in a state where the document presser 4 is opened and the scanner unit 1 is popped up. FIG. 7 is a main longitudinal sectional view of the image forming apparatus in the state of FIG.

(Image forming device)
As shown in FIGS. 1 to 7, the image forming apparatus is attached to an apparatus main body (printer unit 2) having an image forming unit that forms an image on a recording material P, and to be openable and closable with respect to the printer unit 2. And a unit (scanner unit 1). Between the printer unit 2 and the scanner unit 1, a pop-up spring 34 that is an urging mechanism that urges the scanner unit 1 in the opening direction, and manually allowing the scanner unit 1 to move in the opening direction manually. A scissor link unit 100 is provided as a braking mechanism that brakes movement of the scanner unit 1 in the opening direction when the urging force of the scanner unit 1 in the opening direction is lost.

  In the image forming apparatus, a scanner unit 1 as an image reading unit is disposed on an upper part of a printer unit 2 that is a main body of the apparatus, and a discharge stacking unit 3 is formed between the printer unit 2 and the scanner unit 1.

  The printer unit 2 has a cassette 9 as a recording material stacking unit on which recording materials P are stacked. The cassette 9 is pulled out to the front of the apparatus (in the direction of the arrow in FIGS. 1 and 2). The recording material P loaded on the cassette 9 is separated and fed one by one by the pickup roller 11.

  The separated and fed recording material P is conveyed to the image forming unit, and is nipped and conveyed by the developing cartridge 7 having the photosensitive drum 12 and the transfer roller 10 to transfer the toner image. The recording material P to which the toner image has been transferred is pressurized and heated by the fixing device 8 to fix the image. The recording material P on which the image has been fixed is discharged and stacked on the discharge tray constituted by the printer unit exterior upper part 16 and the maintenance cover 14 from the rear to the front of the apparatus.

  The scanner unit 1 is a flatbed scanner having a document placement surface. Further, the scanner unit 1 includes an automatic document feeder (ADF) 5 at the upper part, and functions as a sheet-through scanner. The ADF 5 transports U-turns of the originals stacked on the original stacking tray 6 serving as the original stacking means one by one, automatically feeds them to the scanner surface, and stacks them on the original discharge tray 27 on the upper surface of the original retainer 4.

  The scanner unit 1 is formed to be rotatable about a hinge portion 17 at the upper rear end of the printer unit 2. As the scanner unit 1 rotates, the upper part of the printer unit 2 is opened and closed. As a braking mechanism for controlling the opening / closing operation of the scanner unit 1, scissor link units 100 are provided on the left and right sides between the scanner unit 1 and the printer unit 2.

  As shown in FIGS. 4 and 7, the opening 13 is exposed by opening the scanner unit 1 and opening the maintenance cover 14 above the printer unit 2. Through this opening 13, maintenance such as replacement of the cartridge 7 inside the printer 2 and jam processing can be performed.

(Scissor Link Unit 100)
Here, scissor link unit 100 will be described in detail. The scissor link unit 100 is provided behind the hinge portion of the maintenance cover 14, and is disposed at a position that does not interfere with maintenance of the cartridge 7 from the opening portion 13 when the maintenance cover 14 is opened, such as replacement of the cartridge 7 or jam processing. Has been.

  FIG. 8 is a perspective view of the scissor link unit 100 with the scanner unit 1 opened. FIG. 9 is a main longitudinal sectional view of the scissor link unit 100 in a state where the scanner unit 1 is opened (state shown in FIG. 8).

  As shown in FIG. 8, the scissor link unit 100 is formed by connecting a first arm 101 and a second arm 102 through a link pipe 103 so as to be rotatable within a predetermined angle by a link shaft 104. The link pipe 103 is provided with a torsion coil spring 105 as a weight balance means, and biases the first arm 101 and the second arm 102 in the opening direction.

  The first arm 101 has a rotating shaft 110 formed at the end, and the rotating shaft 110 is rotatably fitted in the scanner unit 1. The second arm 102 has a rotating shaft 111 at the end, and the rotating shaft 111 is rotatably fitted to a scissor link base 113 provided on the printer unit 2 side. Accordingly, the first arm 101 can be rotated with respect to the scanner unit 1 and the second arm 102 can be rotated with respect to the printer unit 2 in accordance with the opening and closing of the scanner unit 1.

  As shown in FIG. 9, the opening angle of the first arm 101 is restricted by abutting against a stopper 106 formed by the wall surface of the second arm 102.

  The torsion coil spring 105 has a torsional angular moment set so that the weight balance with the scanner unit 1 can be achieved. Therefore, when the angle between the scanner unit 1 and the printer unit 2 is within a predetermined angle, the weight of the scanner unit 1 and the biasing force of the torsion coil spring 105 are balanced, and the scanner unit 1 is supported by the user. Holds the open state without any (free stop). Thus, by using the torsion coil spring 105, the weight balance can be easily adjusted only by the torsion coil spring 105.

  Further, as shown in FIGS. 8 and 9, at least one of the left and right scissor link units 100 is provided with a large gear 107, a small gear 108, and a one-way hinge 109 that constitute load applying means.

  The large gear 107 is a fan-shaped first gear centered on the rotation shaft 111 and is provided on the second arm 102. The large gear 107 meshes with a small gear 108 that is a circular second gear provided on the scissor link base 113.

  The small gear 108 is fixed to a one-way gear shaft 112. The one-way gear shaft 112 is inserted into a one-way hinge 109 and is supported at both ends rotatably by frames 113a and 113b extending from the scissor link base 113.

  In such a configuration, when the scanner unit 1 is opened, the scissor link unit 100 is opened, the second arm 102 is rotated so as to be lifted, and the large gear 107 is rotated in the arrow R direction. In accordance with this, the small gear 108 meshed with the large gear 107 rotates in the direction of arrow L together with the one-way gear shaft 112.

  At this time, the one-way hinge 109 generates a predetermined torque with respect to the one-way gear shaft 112. With this torque, the scanner unit 1 is prevented from opening vigorously by the urging force of the torsion coil spring 105, and the scanner unit 1 is opened with an appropriate force.

  On the other hand, when the scanner unit 1 is closed, the large gear 107 and the small gear 108 rotate reversely, and the one-way hinge 109 rotates idly. Therefore, there is no load due to the one-way hinge 109 for the operation of closing the scanner unit 1, and the weight balance due to the torsion coil spring 105 of the scissor hinge unit 100 is maintained.

  The torsion coil spring 105, the large gear 107, the small gear 108, and the one-way hinge 109 may be installed on at least one of the left and right scissor links 100.

(Operation to open the scanner unit 1)
Next, an operation for opening the scanner unit 1 will be described. First, an operation of opening the scanner unit 1 with the document presser 4 closed will be described. As shown in FIG. 3, when both the document presser 4 and the scanner unit 1 are closed with respect to the printer unit 2, the lock lever 20 is hooked on the hook unit 32 provided on the bottom surface of the scanner unit 1 and locked. It has become.

  The distance L2 from the hinge part 17 to the front surface of the scanner part 1 is sufficiently longer than the distance L1 from the hinge part 17 to the scissor link 100. Therefore, when the scanner unit 1 is lifted by holding the lower side of the operation unit 18 provided on the front surface of the scanner unit 1 against a predetermined torque by the one-way hinge 109, the scanner unit 1 can be lifted with a small force by the principle of the lever. I can do it.

  When the unlock button 20a is pressed while the scanner unit 1 is closed and locked, the lock is released. Then, the pop-up spring 34 pushes up the pressing portion 33 provided on the lower surface of the scanner unit 1, and the scanner unit 1 is slightly opened (popped up) as shown in FIG. In the pop-up state, the scanner unit 1 is opened to a state where it does not hook on the hook unit 32 even when the lock lever 20 returns to the original position.

  From this state, the user can lift the scanner unit 1 together with the document presser 4 to the state shown in FIG. Since the scanner unit 1 is balanced in weight by setting the torsion coil spring 105, this state can be maintained even if the user releases his / her hand.

  Next, an operation of opening the scanner unit 1 in a state where the document presser 4 is opened with respect to the scanner unit 1 will be described. The document presser 4 can also be opened and closed by a predetermined angle with respect to the scanner unit 1 around the hinge unit 19. The hinge portion 19 is provided with a weight balancing mechanism that supports an opening / closing operation using a compression spring and a cam that are generally used conventionally. Therefore, the document retainer 4 can hold the opened state.

  As shown in FIG. 5, the center of gravity of the scanner unit 1 is moved from the center of gravity position G1 when the document retainer 4 is closed to the center of gravity position G2 behind the scanner unit 1 with the document retainer 4 opened. Since the center of gravity position G2 is closer to the hinge portion 17 that is the center of rotation than the center of gravity position G1, the scanner unit 1 is in a state where it can be easily opened.

  Therefore, when the lock release button 20a is pressed, the lock is released, and the scanner unit 1 is slightly opened by the pop-up spring 34, and opens rearward as it is popped up. When the position of the center of gravity moves rearward from the hinge portion 17, a moment to open the scanner portion 1 starts to act, so the opening speed of the scanner portion 1 is accelerated.

  However, as shown in FIGS. 8 and 9, a predetermined load is applied to the second arm 102 constituting the scissor link unit 100 in the direction to be opened by the one-way hinge 109 as described above. Therefore, in practice, the scanner unit 1 does not open suddenly. In other words, by setting the torque of the one-way hinge 109, the scanner unit 1 can be opened slowly, or the scanner unit 1 can be stopped in a pop-up state, and the user can manually open the document presser 4 in the closed state. You can also.

  As described above, the provision of the braking mechanism eliminates the risk of the scanner unit 1 being opened violently, the risk of damage to the device, and the risk of falling, and the scanner unit 1 can be opened and closed safely and smoothly. . In addition, the user can open and close naturally without paying special attention to the opening and closing operation of the scanner unit 1 regardless of whether the document presser 4 is closed or open.

  In addition, the conventional weight balancing mechanism using the compression spring and cam used in the opening / closing hinge portion of the original platen of the copying machine can only deal with a fixed center of gravity, whereas the braking mechanism of the present invention. Then, with a simple configuration, weight balance can be achieved even at different positions of the center of gravity, and costs can be reduced.

  As shown in FIG. 7, the distance L4 from the hinge portion 17 to the scissor link unit 100 is longer than the distance L3 from the center of gravity position G2 to the hinge portion 17 with the document presser 4 opened. Further, the force F1 × L3 for opening the scanner unit 1 at the center of gravity position G2 and the predetermined load F2 × L4 by the one-way hinge 109 become equal, so that the scanner unit 1 stops. Therefore, the balance between the force for opening the scanner unit 1 with the document retainer 4 closed and the force for suppressing the scanner unit 1 from opening with the document retainer 4 open is within the practical range. I can take it.

  FIG. 10 is a main longitudinal sectional view of the scissor link unit 100 in a state where the scanner unit 1 is closed and locked and folded. As shown in FIG. 10, the one-way hinge 109 is configured such that the outer shape is held with a gap Δ1 by the rib portion 114 of the scissor link base 113, and when the scanner portion 1 pops up, the one-way clutch 109 itself Can be rotated. For this reason, when the scanner unit 1 pops up, no load is applied. Note that the amount of rotation of the second arm 102 of the scissor link unit 100 is very small with respect to the pop-up amount of the scanner unit 1, and the backlash amount of the large gear 107 and the small gear 108 is sufficient.

[Second Embodiment]
Next, a second embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 11 is a perspective view of the scissor link unit 200 in a state where the scanner unit 1 according to the present embodiment is opened. FIG. 12 is a main longitudinal sectional view of the scissor link unit 200 in the state of FIG. About the part which overlaps with said 1st embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIGS. 11 and 12, the image forming apparatus of the present embodiment is provided with different scissor link units 200 and 300 on the left and right as a braking mechanism instead of the scissor link unit 100 of the first embodiment. is there.

  As shown in FIG. 11, in the scissor link unit 200, a first arm 201 and a second arm 202 are connected by a curl type friction hinge 203 which is a weight balance unit and a load application unit. The friction hinge 203 is formed by fixing the fixed shaft 203c to the fixed bracket 203b and winding the movable bracket 203a so as to tighten the fixed shaft 203c. Then, torque is generated by the frictional force between the movable bracket 203a and the fixed shaft 203c. An opening 203d exists at the winding end of the movable bracket 203a.

  In manufacture, the movable bracket 203a is wound slightly smaller than the diameter of the fixed shaft 203c, and grease is applied to the fixed shaft 203c and press-fitted. The fixed bracket 203b is fixed to the second arm 202 with screws 207, and the movable bracket 203a is fixed to the first arm 201 with screws 207.

  As shown in FIG. 12, the winding direction of the movable bracket 203a is the counterclockwise direction in FIG. When the scissor link unit 200 is rotated in the opening direction, the winding portion of the movable bracket 203a is deformed in a direction of loosening the fastening of the fixed shaft 203c. When the scissor link unit 200 is rotated in the folding direction, the winding portion of the movable bracket 203a is deformed in the direction in which the fixed shaft 203c is tightened. Accordingly, a small torque is generated when the scissor link unit 200 is opened, and a large torque is generated when the scissor link 200 is folded.

  As shown in FIG. 13, the other scissor link unit 300 is provided with a torsion coil spring 305 as a weight balance means on a link shaft 304 connecting the first arm 301 and the second arm 302. The torsion coil spring 305 biases the first arm 301 and the second arm 302 in the opening direction.

  Here, the spring force of the torsion coil spring 304 and the torque generated when the friction hinge 203 is closed are set so that the weight balance with the scanner unit 1 is achieved. That is, the resultant force of the torque required when the scissor link unit 300 is opened by the biasing force of the torsion coil spring 305 and the scanner unit 1 is opened and the torque required when the scissor link unit 200 is folded by the friction hinge 203 is It is set so as to support the scanner unit 1 in a state where the center of gravity is located forward with the unit 4 closed.

  Accordingly, the scanner unit 1 is free-stopped within a predetermined opening angle range or is slowly closed even when the document presser 4 is in the open state. Further, the scanner unit 1 stops in a pop-up state or opens slowly.

  Further, the torque generated when the friction hinge 203 is opened is such that the center of gravity position is located rearward with the document pressing portion 4 opened, and the scanner portion 1 can be opened rapidly when the lock release button 20a is pressed to release the lock. This is the torque necessary to suppress this.

  Here, in a state where the scanner unit 1 is opened with the document holder 4 closed (the state shown in FIG. 4), the moment around the rotation of the hinge portion 17 when the scanner unit 1 is closed causes the document holder 4 to open. When the scanner unit 1 is closed in the closed state (the state shown in FIG. 5), the moment about the hinge portion 17 when the scanner unit 1 is opened is greater than the moment of rotation.

  As described above, by using the friction hinge 203, it is possible to suppress an increase in operating force when the scanner unit 1 is opened with the document presser 4 closed, and an operating force when closing and a uniform small operating force. It is possible to open and close with.

  If the same torque is generated when the friction hinge 203 is opened and closed, the operating force when the scanner unit 1 is opened with the document presser 4 closed is increased, and usability is deteriorated.

[Third embodiment]
Next, a third embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 14 is a perspective view of the scissor link unit 400 with the scanner unit 1 opened. FIG. 15 is a main longitudinal sectional view of the scissor link unit 400 with the scanner unit 1 opened. FIG. 16 is a main longitudinal sectional view of the scissor link unit 400 in a folded state. FIG. 17 is a main longitudinal sectional view of the scissor link unit 400 with the scanner unit 1 popped up. About the part which overlaps with said 1st embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 14, the image forming apparatus according to the present embodiment is provided with a scissor link unit 400 as a braking mechanism instead of the scissor link unit 200 of the second embodiment.

  The scissor link unit 400 deletes the pop-up spring 34 and applies an opening force between the first arm 201 and the second arm 402 of the scissor link unit 200 (a cylindrical portion 402a, a cap 403, a compression spring 405). ) Is added. That is, the first arm 201 and the second arm 402 are connected by the friction hinge 203.

  As shown in FIG. 15, the second arm 402 is provided with a cylindrical part 402a, and a cap 403 is slidably provided in the cylindrical part 402a. A compression spring 405 is provided between the rod portion extending from the cap 403 and the cylindrical portion 402a of the second arm 402, and the cap 403 is prevented from coming off by an E-ring 404 at the end of the rod portion.

  The top of the cap 403 has a spherical shape, and a pressing force acts in the sliding direction so that the first arm 201 can be pressed by the top. The compression spring 405 is set so that a force larger than the torque required in the opening direction of the friction hinge 203 acts.

  As shown in FIG. 16, when the lock release button 20a is pressed to release the lock while the scissor link unit 400 is folded, the force that the scissor link unit 400 opens by the compression spring 405 and the other scissor link The resultant force of the scissor link unit 300 to open by the torsion coil spring 305 provided in the unit 300 overcomes the weight of the scanner unit 1 and pops up the scanner unit 1 to the state shown in FIG.

  As shown in FIG. 16, a gap Δ2 is provided between the rotating shaft 210 of the first arm 201 and the bearing portion of the scanner unit 1, and only the first arm 201 rotates and opens in the pop-up range. The second arm 402 is configured not to move.

  As described above, by providing an urging mechanism (402a, cap 403, compression spring 405) that applies an opening force between the first arm 201 and the second arm 402, the scanner unit 1 can be reliably popped up. Can do. Further, when the scanner unit 1 pops up, the first arm 201 and the second arm 402 are united by the torque of the friction hinge 203 so that the entire scissor link 400 is centered on the rotation axis 411 of the second arm 402 as the center of rotation. Oscillating motion between 1 and the scissor link table 413 can be prevented to generate a sound that hits the rattle.

FIG. 2 is a perspective view of the image forming apparatus according to the first embodiment as viewed from the front right side of the image forming apparatus (a state where the scanner unit is opened with the document presser closed). FIG. 2 is a perspective view of the image forming apparatus as viewed from the front right side of the apparatus (a state where the scanner unit is opened with the document presser opened). 1 is a main longitudinal sectional view of an image forming apparatus (a state where both a document presser and a scanner unit are closed); FIG. 3 is a main longitudinal sectional view of the image forming apparatus (a state where the scanner unit is opened with the document presser closed). 1 is a main longitudinal sectional view of an image forming apparatus (a state where a scanner unit is closed and only a document presser is opened); 1 is a main longitudinal sectional view of an image forming apparatus (a scanner unit is popped up and a document presser is opened). FIG. FIG. 3 is a main longitudinal sectional view of the image forming apparatus (a state where the scanner unit is opened with the document presser opened); It is a perspective view of a scissor link mechanism (open state). It is a main longitudinal cross-sectional view of a scissor link mechanism (open state). It is a main longitudinal cross-sectional view of a scissors link mechanism (folded state). It is a perspective view of one scissor link mechanism (open state) concerning a second embodiment. It is a main longitudinal cross-sectional view of one scissor link mechanism (open state) concerning 2nd embodiment. It is a perspective view of the other scissor link mechanism (open state) concerning a second embodiment. It is a perspective view of one scissor link mechanism (open state) concerning a third embodiment. It is a main longitudinal cross-sectional view of one scissor link mechanism (open state) concerning 3rd embodiment. It is a main longitudinal cross-sectional view of one scissor link mechanism (folded state) concerning 3rd embodiment. It is a main longitudinal cross-sectional view of one scissor link mechanism (pop-up state) concerning 3rd embodiment. FIG. 6 is a perspective view of the conventional image forming apparatus as seen from the front right side (the state where both the document presser and the scanner unit are closed). FIG. 10 is a perspective view of the conventional image forming apparatus viewed from the front right side (a state where the scanner unit is opened with the document presser closed). FIG. 6 is a main longitudinal sectional view of a conventional image forming apparatus (a state where both a document presser and a scanner unit are closed). FIG. 6 is a main longitudinal sectional view of a conventional image forming apparatus (a state where a scanner unit is opened with a document presser closed). FIG. 6 is a main longitudinal sectional view of a conventional image forming apparatus (a state where only a document presser is opened with a scanner unit closed); FIG. 6 is a main longitudinal sectional view of a conventional image forming apparatus (a state where a scanner unit is opened with a document presser opened);

Explanation of symbols

Δ1, Δ2: Gap, G1, G2: Center of gravity, L1 to L4: Distance, P ... Recording material, 1 ... Scanner unit, 2 ... Printer unit (corresponding to the apparatus main body), 3 ... Discharge stacking unit, 4 ... Document holder, 5 ... ADF, 6 ... Document stacking tray, 7 ... Developing cartridge, 8 ... Fixing device, 9 ... Cassette, 10 ... Transfer roller, 11 ... Pickup roller, 12 ... Photosensitive drum, 14 ... Maintenance cover, 15, 17, 19 ... Hinge part, 16 ... Printer unit exterior upper part, 18 ... Operation part, 20 ... Lock lever, 20a ... Unlock button, 27 ... Document discharge tray, 32 ... Hook part, 33 ... Press part, 34 ... Pop-up spring (Corresponding to the biasing mechanism), 100, 200, 300, 400 ... scissor link unit (corresponding to the braking mechanism), 101, 201, 301 ... first arm, 102, 202, 302, 402 ... second arm, 103 ... Link pipe, 104, 304 ... Link shaft, 105, 305 ... Torsion coil spring (weight loose) 106 ... stopper, 107 ... large gear, 108 ... small gear, 109 ... one-way hinge (corresponding to load applying means), 110, 111, 210, 411 ... rotary shaft, 113 ... scissor link base, 113a , 113b ... frame, 114 ... rib part, 203 ... friction hinge (corresponding to weight balance means and load applying means), 203a ... movable bracket, 203b ... fixed bracket, 203c ... fixed shaft, 203d ... opening, 402a ... cylindrical shape Part, 403 ... cap, 404 ... E-ring, 405 ... compression spring (corresponding to urging mechanism),

Claims (14)

In an image forming apparatus having an apparatus main body having an image forming unit for forming an image on a recording material, and a unit attached to the apparatus main body so as to be openable and closable.
Between the apparatus main body and the unit, an urging mechanism for urging the unit in the opening direction, and manually attaching the unit in the opening direction while allowing the unit to move in the opening direction manually. An image forming apparatus, comprising: a braking mechanism that brakes movement of the unit in the opening direction when power is lost.
The braking mechanism is provided between the apparatus main body and the unit, and a first arm and a second arm that can be opened and closed, and a weight balance unit that biases the first arm and the second arm in a direction of opening. The image forming apparatus according to claim 1, further comprising: a load applying unit that applies different loads depending on whether the first arm and the second arm are opened or folded.
The weight balance means is configured to bias the unit so that the unit is not closed by its own weight when the center of gravity of the unit is at a position where the unit is closed by its own weight so as to balance the weight. The image forming apparatus according to claim 2.
4. The image forming apparatus according to claim 2, wherein the load applying unit applies a load sufficient to suppress a behavior of the unit to open vigorously. 5.
The image according to any one of claims 2 to 4, wherein the load applying unit applies a predetermined amount of load only in a direction in which the first arm and the second arm are opened. Forming equipment.
The load applying means includes a first gear provided on the second arm, a second gear provided on the apparatus main body side and meshing with the first gear, the first arm, and the second arm. A one-way hinge that idles when the first gear rotates in the folding direction and generates a predetermined torque only when the first gear rotates in the direction to open the first arm and the second arm; The image forming apparatus according to claim 2, wherein the image forming apparatus is provided.
A predetermined amount of backlash is provided in meshing between the first gear and the second small gear, or the one-way hinge itself is rotatable by a predetermined amount, and the first arm and the second arm are folded. The image forming apparatus according to claim 6, wherein when the first gear is slightly opened, no torque is generated when the first gear rotates.
The image according to any one of claims 2 to 7, wherein the weight balance means is a torsion coil spring provided on a link shaft that connects the first arm and the second arm. Forming equipment.
The weight balance means and the load application means connect the first arm and the second arm, and a link shaft fixed to one of the first arm or the second arm, and the first arm, or A curl type friction hinge comprising a link bearing provided on the other side of the second arm and wound around the link shaft so as to be tightened with a predetermined load;
8. The torque according to claim 2, wherein when the first arm and the second arm are folded, a larger torque is generated than when the first arm and the second arm are opened. 2. The image forming apparatus according to item 1.
As the weight balance means,
A torsion coil spring provided on a link shaft connecting the first arm and the second arm;
A link shaft that connects the first arm and the second arm and is fixed to one of the first arm or the second arm, and is provided on the other of the first arm or the second arm, and the link shaft A link bearing wound so as to be tightened with a predetermined load, and a curl type friction hinge.
The resultant force of the biasing force of the torsion coil spring when the first arm and the second arm are folded and the torque of the friction hinge is such that the center of gravity of the unit closes due to its own weight. 8. The image forming apparatus according to claim 2, wherein the unit is supported so that the unit is not closed in some cases to achieve a weight balance. 9.
The biasing mechanism is provided between the first arm and the second arm, and the friction hinge opens the unit with a biasing force larger than a torque generated when the first arm and the second arm are opened. The image forming apparatus according to claim 9, wherein the image forming apparatus is an elastic unit.
The unit is an image reading unit that reads an original and supplies read image information to the apparatus main body.
12. The image reading means according to claim 1, further comprising: a document placing surface on which a document is placed; and an openable / closable document presser that presses and holds the document against the document placing surface. The image forming apparatus according to claim 1.
The document presser includes a document stacking unit that loads a document, and an automatic document feeding unit that automatically feeds the document loaded on the document stacking unit so that the scanner unit reads the document. The image forming apparatus according to claim 12.
A discharge stacking unit that is provided between the apparatus main body and the unit and discharges and stacks the recording material on which an image is recorded by the image forming unit;
2. A part of the upper exterior of the discharge stacking part is configured to be openable and closable, and the braking mechanism is provided behind a part of the opening / closing hinge part of the upper exterior of the discharge stacking part. The image forming apparatus according to claim 13.

Images