JP3740263B2 - Locking member, sheet stacking apparatus, and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a locking member that is attached to suppress vibration of a sheet stacking table during transfer of a sheet feeding device that is used by being mounted on an image forming apparatus such as a printer, a copier, or a facsimile machine. The present invention relates to an attachable sheet stacking apparatus, and further to an image forming apparatus using the sheet stacking apparatus.
[0002]
[Prior art]
Conventionally, a feeding cassette capable of stacking and storing a plurality of sheets needs to suppress vibration of the sheet stacking table during product transfer and prevent damage to the feeding cassette.
[0003]
For example, a configuration as shown in FIGS. 10 and 11 is known. FIG. 10 is an explanatory plan view of a feeding cassette D that is a sheet stacking apparatus, and FIG. 11 is an explanatory diagram of a UU cross section of FIG. In the figure, reference numeral 50 denotes an intermediate plate that is a rotatable sheet stacking base, and 51 denotes an elastic member that urges the intermediate plate upward. The intermediate plate 50 holds the sheet S at a predetermined height, and is attached so as to be rotatable around a rotation center 52 provided on the side surface of the cassette. 53 and 54 are side end regulating guides for regulating the position of the side end in the width direction orthogonal to the feeding direction of the sheet S.
[0004]
Separating claws 55 and 56 are swingably attached to the side end regulating guides 53 and 54, respectively. 53a and 54a are support shafts that swingably support the separation claws 55 and 56, 53b and 54b are locking claws that lock the free ends of the separation claws 55 and 56, and the intermediate plate 50 is an elastic member. It is a stopper when pressed upward by 51.
[0005]
The front wall surface 57 of the feeding cassette D is formed with a locking hole 58 that is a locking portion. E is a locking member, a contact surface 59 that contacts the intermediate plate 50, a contact surface 60 that contacts the front wall surface 57 of the feeding cassette D, and a groove that is inserted into the locking hole 58 and locked. 61 is formed. When the pressing of the intermediate plate 50 is released after the locking member E is inserted into the locking hole 58 while pressing down the intermediate plate 50 against the urging force of the elastic member 51, the groove 61 of the locking member E is formed. The abutting surface 60 of the locking member E comes into contact with the locking portion 62 and is locked by contacting the front wall surface 57 of the feeding force set.
[0006]
[Problems to be solved by the invention]
However, when the conventional sheet stacking apparatus is used, the locking member E that suppresses the swing of the intermediate plate 50 is locked by the urging force of the elastic member 51. If the vibration is large, the locking member E may fall off. In addition, there is a method of preventing the locking member E from falling off by attaching the locking member E in a state where the middle plate 50 is pushed down to the vicinity of the lowest position to increase the urging force. Since excessive force is required, the workability at the time of engagement / disengagement deteriorates. In addition, problems such as a spring sag, deformation of the intermediate plate, and deformation of the spring seat at the bottom of the feeding force set may occur. If a spring sag, deformation of the intermediate plate, or the like occurs, a sheet conveyance failure may occur, and a normal image forming operation may not be performed.
[0007]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems of the prior art. The object of the present invention is to provide a locking member excellent in assembling workability, operability and reliability, and a sheet stacking apparatus capable of attaching the locking member. Another object of the present invention is to provide an image forming apparatus.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a typical configuration according to the present invention includes a sheet stacking table for biasing stacked sheets to a feeding unit, and a sheet stacking apparatus having a locking portion on the downstream side in the sheet feeding direction. attached to, the the sheet stack tray to a locking member that abolish engaging said sheet stacking plate by contact with locked to the locking portion, thus the engagement to biasing movement of said sheet stacking table a first engaged portion which can be engaged with the stopper portion, elastically have a flexibility for enabling disengageable against the locking portion, in locked state with the locking portion And a second locked portion configured not to receive an urging force from the sheet stacking table .
[0009]
According to another aspect of the present invention, there is provided a sheet stacking device in which a sheet stacking table can be locked using the locking member, and an image forming apparatus capable of forming an image by mounting the sheet stacking device.
[0010]
In the above configuration, when the first locked portion and the second locked portion of the locking member are locked to the locking portion of the sheet stacking device, the first locked portion is biased by the sheet stacking table. The second locked portion is locked by its own elasticity. Therefore, even if the urging force of the sheet stacking table is weakened, the locking member does not fall off the locking portion. For this reason, in order to lock the locking member, it is possible to reduce the operating force for pushing down the sheet stacking table, and it is possible to improve the assembly workability and the operability.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of a locking member and a sheet stacking apparatus to which the locking member according to the present invention can be attached will be described. A sheet stacking apparatus according to the present invention is used as a sheet stacking apparatus of an image forming apparatus such as a copying machine, a printer, and a facsimile. In the following embodiments, a laser beam printer is exemplified as an image forming apparatus. An embodiment in which the present invention is applied to a sheet stacking apparatus of a printer will be described with reference to FIGS.
[0012]
FIG. 1 is a plan view explanatory view of a feeding cassette, FIGS. 2 to 8 are partial sectional explanatory views of the feeding cassette, and FIG. 9 is an explanatory view showing a schematic configuration of a laser beam printer. In the following description, the schematic configuration of the laser beam printer will be described first, and then the configuration of the feeding cassette unit that is the sheet stacking apparatus according to the present invention will be described.
[0013]
{Image forming device}
First, a schematic configuration of the laser beam printer A will be described with reference to FIG. In FIG. 9, reference numeral 1 denotes an apparatus main body of a laser beam printer, and a lower portion thereof is provided with a mounting portion for a feeding cassette B which is a sheet stacking device for stacking and storing sheets S. A feeding cassette B is attached. The feeding cassette B is configured to be detachable from the apparatus main body 1 of the laser beam printer A. Reference numeral 2 denotes a feeding roller as a feeding means, which feeds the sheets S stacked on the feeding cassette B one by one from the uppermost side. Reference numeral 3 denotes a guide member that guides the sheet S fed by the feeding roller 2. Reference numeral 4 denotes a registration roller pair, which is applied to the nip portion of the stopped roller pair 4 at the leading end of the sheet S to correct skewing, and then rotated at a predetermined timing to convey the sheet S to the image forming unit. To do.
[0014]
A process cartridge 5 is detachably mounted on the apparatus main body 1. Inside the process cartridge 5, an image forming unit such as a primary charger, a developing device, and a cleaning device (not shown) is provided around the photosensitive drum 6. A scanner unit 7 scans the laser beam L in accordance with image information, and performs writing (latent image formation) on the photosensitive drum 6 via the folding mirror 8. A transfer roller 9 is in pressure contact with the photosensitive drum 6, and transfers a developed image (toner image) from the photosensitive drum 6 when the sheet S passes between the transfer roller 9 and the photosensitive drum 6. Is done.
[0015]
A conveyance guide 10 guides the sheet S after image transfer to the fixing device 11. The fixing device 11 fixes an image (toner image) transferred to the sheet S, and includes a fixing inlet guide 11a, a fixing roller 11b, a pressure roller 11c, and a fixing discharge roller pair 11d. A pair of discharge rollers 12 discharges the sheet S after image fixing outside the apparatus with the image surface facing down. A discharge tray 13 is formed on the upper surface of the apparatus main body 1 and holds and holds the sheets S discharged outside the apparatus after image fixing.
[0016]
The image forming operation of the laser beam printer configured as described above will be described. When an image formation is instructed from a host computer (not shown), first, the feeding roller 2 rotates to rotate the uppermost sheet in the feeding cassette B. The sheets are fed one by one from S, guided by the guide member 3 and guided to the registration roller pair 4. The registration roller pair 4 conveys the sheet S between the photosensitive drum 6 and the transfer roller 9 in synchronization with the image formed on the photosensitive drum 6, and the sheet S is transferred to the photosensitive drum 6 and the transfer roller. An image (toner image) is transferred when passing between the two.
[0017]
Further, the sheet S after the image transfer is conveyed along the conveyance guide 10 to the fixing device 11, and when passing between the fixing roller 11b and the pressure roller 11c, heat and pressure are applied to fix the transferred image. Is done. The sheet S after image fixing is conveyed by the fixing discharge roller pair 11d, and further discharged and stacked on the discharge tray 13 by the discharge roller pair 12.
[0018]
{Sheet stacking device and locking member}
Next, a specific configuration of the feeding cassette B as a sheet stacking apparatus according to the present invention and a locking member attached thereto will be described with reference to FIGS.
[0019]
FIG. 1 is an explanatory plan view of a feeding cassette B that is a sheet stacking apparatus, FIG. 2 is an explanatory view taken along a line XX in FIG. 1, and FIG. 3 is an explanatory view taken along a line YY in FIG. As shown in the figure, an intermediate plate 14 that is a sheet stacking base is rotatably mounted around a rotation shaft 15 provided on the side of the cassette, and the intermediate plate 14 is attached by a spring 16 that is a biasing means. The sheet S stacked by being biased upward is held at a predetermined height. Further, the position of the side end in the width direction orthogonal to the feeding direction of the sheet S is regulated by the side end regulating guides 17 and 18.
[0020]
Separating claws 19 and 20 are attached to the side end regulating guides 17 and 18 so as to be swingable around the support shafts 17a and 18a, respectively. The free ends of the separating claws 19 and 20 can be locked to locking claws 17b and 18b formed on the side end regulating guides 17 and 18. The locking claws 17b and 18b It serves as a stopper when the plate 14 is pressed upward by the spring 16.
[0021]
A front wall surface 21 is formed on the front side in the sheet feeding direction of the feeding cassette B, and a locking hole 22 serving as a locking portion for locking a locking member C (described later) is formed at a substantially central portion of the front wall surface 21. Is formed. As shown in FIG. 4 (the Z-Z cross-sectional explanatory view of FIG. 1), the locking hole 22 includes a first locking part 22a hanging from above the locking hole 22 and side edges of the locking hole 22. A certain second locking portion 22b is formed.
[0022]
The locking member C locked in the locking hole 22 is for locking the middle plate 14 when the feeding cassette B is transferred and for restricting the movement of the middle plate 14. 1 to 3, the locking member C includes a first locked portion 23 that can be locked to the first locking portion 22a of the locking hole 22 by the urging force of the intermediate plate 14, The second locking portion 22b is constituted by two second locked portions 24 having flexibility that can be elastically engaged and disengaged.
[0023]
As shown in FIG. 2, a concave groove 23a is formed in the first locked portion 23, and an inclined surface 23b serving as a guide portion is formed on one side wall surface of the groove 23a. . On the other side wall surface, an abutting surface 23c that abuts on the front wall surface 21 of the feeding cassette B is formed. An inclined surface 23 d is formed at the tip of the first locked portion 23.
[0024]
On the other hand, as shown in FIG. 1, convex locking claws 24a are formed symmetrically on the outer end of the second locked portion 24 on the free end side. An inclined surface 24b is also formed at the tip of the locking claw 24a. In addition, an anti-slip portion 24c having a concavo-convex shape is formed at the center of the second locked portion 24.
[0025]
Further, as shown in FIG. 2 and FIG. 3, a convex contact surface 25 that contacts the intermediate plate 14 is formed on the lower surface of the locking member C, and this contact surface 25 is rotated around the intermediate plate 14. It is formed so as to contact the upper surface of the moving side end. An inclined surface 26 is formed at the rising portion of the contact surface 25.
[0026]
Next, a method for engaging and disengaging the locking member C with the locking hole 22 will be described. First, in the state of FIG. 5, the middle plate 14 is pushed down with one hand, and the second locked portion 24 of the locking member C is picked up with the other hand and inserted in the direction of arrow C in FIG. As shown in FIG. 7, the locking member C is easily moved into the locking hole 22 because the locking claw 24 a is flexed inward by picking the anti-slip portion 24 c. Further, as shown in FIGS. 1 and 2, since the inclined surfaces 23d and 24b are formed on the first locked portion 23 and the second locked portion 24, respectively, the first locking portion shown in FIG. It can approach while being guided by 22a and the 2nd latching | locking part 22b.
[0027]
Next, as shown in FIG. 8, when the contact surface 23c of the locking member C contacts the front wall surface 21 of the feeding cassette B, the middle plate 14 is pushed down after the hand holding the locking member C is released. Release your hands. At this time, the locking claw 24a of the second locked portion 24 opens outward, is locked by the second locking portion 22b of the locking hole 22, and does not move in the direction of arrow D in FIG. The locking member C is pushed up in the direction of arrow E in FIG. At this time, the first locking portion 22a of the locking hole 22 enters the groove 23a while being guided by the inclined surface 23b and the contact surface 23c of the first locked portion 23.
[0028]
As shown in FIG. 2, when the second locking portion 22b comes into contact with the bottom surface of the groove 23a of the locking member C, the rotational moment in the direction of arrow F in FIG. Work. Then, the abutment surface 23c of the locking member C abuts against the front wall surface 21 of the feeding cassette B, whereby the rotation of the intermediate plate 14 is restricted. At this time, the latching claw 24a of the second latched portion 24 does not contact the upper end of the latching hole 22 as shown in FIG.
[0029]
Since the middle plate 14 is always urged upward by the spring 16, the middle plate 14 may vibrate greatly in the directions of arrows G and H in FIG. When the middle plate 14 is greatly pushed down in the direction of arrow H in FIG. 2 by this vibration, the locking member C also moves in the direction of arrow I in FIG. 8 and the locking of the first locked portion 23 is released. However, at this time, since the locking claw 24a of the second locked portion 24 is still locked, it does not move in the direction of arrow D in FIG. When the intermediate plate 14 is pushed back in the direction of arrow G in FIG. 2, the first locking portion 22a of the locking hole 22 enters the groove 23a of the locking member C and is locked again.
[0030]
Thus, not only the first locked portion 23 is locked to the locking hole 22 by the biasing force of the intermediate plate 14, but also the second locked portion 24 is locked to the locking hole 22 by its own elasticity. Stop. For this reason, even if the urging force of the intermediate plate 14 is weakened, the locking member C does not fall out of the locking hole 22. Therefore, in order to lock the locking member C, the operating force for pushing down the intermediate plate 14 can be reduced.
[0031]
Normally, a separation sheet 27, which is a sheet-like friction member, is provided on the intermediate plate 14 to prevent double feeding of the lowest sheet. In order not to damage the surface of the separation sheet 27, an inclined surface 26 is formed at the end of the contact surface 25 formed on the locking member C so that the contact surface 25 does not contact the separation sheet 27. ing.
[0032]
In the case of removing the locking member C, the middle plate 14 is pushed down with one hand and the second locked portion 24 of the locking member C is picked with the other hand as shown in FIG. Pull it out in the direction of arrow D. At this time, as shown in FIG. 3, since the urging force of the intermediate plate 14 does not act on the locking claw 24a of the locking member C, the operation of gripping the second locked portion 24 can be easily performed. In addition, since the inclined surface 26 is formed on the lower surface of the locking member C, it is not caught on the separation sheet 27 provided on the intermediate plate, so that the separation sheet 27 can be prevented from being peeled off or damaged. .
[0033]
In the above-described embodiment, the laser beam printer is exemplified as an example of the image forming apparatus. However, this is naturally applicable to other image forming apparatuses such as a copying machine and a facsimile machine. .
[0034]
【The invention's effect】
Since the present invention is configured as described above, it is possible to prevent the locking member from coming off due to the vibration of the sheet stacking table during transfer without increasing the amount by which the sheet stacking table is pushed down when the locking member is mounted. Can do. Thereby, it is possible to reduce an operation force for pushing down the sheet stacking table when the locking member is engaged and disengaged. In addition, since the urging force of the sheet stacking table does not act on the flexible second locked portion of the locking member, it can be flexed with a small operating force, and the operability is dramatically improved.
[0035]
In addition, since the amount by which the sheet stacking table is pushed down is small, the load of the urging means acting on the sheet stacking device when the locking member is mounted can be reduced. Can be prevented. Further, since problems such as spring sag and deformation of the sheet stacking table are solved, the sheet transportability is not impaired.
[0036]
In addition, since the pressing force of the sheet stacking table is small, it is possible to prevent scratching due to vibration on the contact surface of the sheet stacking table with the locking member, and to prevent the occurrence of rust and the appearance. In addition, since the scratches due to vibration hardly occur on the contact surface between the front wall surface of the sheet stacking device and the locking member, the fed sheet is not caught. Since the urging force of the sheet stacking table does not act on the flexible second locked portion of the locking member, it is not deformed or damaged even if stored for a long time.
[Brief description of the drawings]
FIG. 1 is an explanatory plan view of a feeding cassette.
FIG. 2 is a cross sectional view taken along the line XX of FIG.
3 is a cross-sectional view taken along the line YY in FIG.
FIG. 4 is an explanatory diagram of a ZZ cross section of FIG. 1;
FIG. 5 is a cross-sectional explanatory view of a main part showing a state before the locking member is attached to the locking hole of the cassette.
FIG. 6 is an explanatory cross-sectional view of a main part showing a state in which a locking member is inserted into a locking hole by pushing down the middle plate of the cassette.
FIG. 7 is an explanatory view showing a state in which the second locked portion of the locking member is bent and inserted into the locking hole.
FIG. 8 is an explanatory cross-sectional view of a main part showing a state in which a locking member is attached to the locking hole.
FIG. 9 is an explanatory diagram showing a schematic configuration of a laser beam printer.
FIG. 10 is an explanatory plan view of a feeding cassette.
11 is a cross-sectional explanatory view taken along the line U-U in FIG. 10;
[Explanation of symbols]
A ... Laser beam printer B ... Feed cassette C ... Locking member L ... Laser beam S ... Sheet 1 ... Main body 2 ... Feeding roller 3 ... Guide member 4 ... Registration roller pair 5 ... Process cartridge 6 ... Photoconductor drum 7 ... Scanner unit 8 ... Mirror 9 ... Transfer roller
10… Conveyance guide
11… Fixing device
11a ... Fixing entrance guide
11b: Fixing roller
11c… Pressure roller
11d: Fixing discharge roller pair
12… discharge roller pair
13… discharge tray
14 ... Middle plate
15… Rotation axis
16 ... Spring
17, 18 ... Side end restriction guide
17a, 18a ... support shaft
17b, 18b ... locking claw
19, 20 ... Separation claw
21… Front wall
22… Locking hole
22a ... 1st locking part
22b ... second locking part
23… First locked part
23a ... groove
23b ... Inclined surface
23c ... Contact surface
23d ... inclined surface
24… Second locked part
24a ... locking claw
24b ... Inclined surface
24c ... Anti-slip part
25… contact surface
26… Inclined surface
27… Separation sheet

Claims (7)

It has a sheet stacking table that urges the stacked sheets to the feeding means, and is attached to a sheet stacking device having a latching portion on the downstream side in the sheet feeding direction, and comes into contact with the sheet stacking table to the latching portion a locking member that abolish engaging said sheet stacking plate by locking,
And lockable first engaged portion to said sheet stacking plate the locking portion depending on the biasing movement of the resiliently have a flexibility for enabling disengageable against the locking portion And a second locked portion configured not to receive a biasing force from the sheet stacking table while being locked to the locking portion.   The locking member according to claim 1, wherein the first locked portion includes a guide portion so as to be locked to the locking portion in conjunction with the urging movement of the sheet stacking table.   The locking member according to claim 1, wherein the second locked portion has an uneven slip preventing portion. The locking member according to claim 1, wherein an inclined surface is formed on a contact surface with the sheet stacking table. In a sheet stacking apparatus that is mounted on a feeding unit of an image forming apparatus and stacks sheets,
A sheet stacking table for loading sheets;
An urging unit for urging the sheet stacking unit to urge the stacked sheets to a feeding unit;
A locking portion for locking the locking member according to any one of claims 1 to 4 on the downstream side in the sheet feeding direction;
A sheet stacking apparatus comprising: The locking part has a first locking part locked by a first locked part of the locking member and a second locking part locked by a second locked part of the locking member. The sheet stacking apparatus according to claim 5 . In an image forming apparatus that forms an image by feeding a sheet,
A mounting portion for detachably mounting the sheet stacking apparatus according to claim 5 or 6 ,
A feeding means for feeding the sheets stacked on the sheet stacking device;
Image forming means for forming an image on the fed sheet;
An image forming apparatus comprising:

Images