This application is based on and claims the benefit of priorities from Japanese Patent application No. 2014-143445 filed on Jul. 11, 2014 and Japanese Patent application No. 2015-137912 filed on Jul. 9, 2015, the entire contents of which are incorporated herein by reference.
The present disclosure relates to a self-closing device which retracts a unit such as a sheet feeding cassette to an apparatus main body and an image forming apparatus including this self-closing device.
In an image forming apparatus such as a printer or a multifunction peripheral, a sheet feeding cassette in which a sheet to be image-formed is housed is configured to be able to be pulled out with respect to an apparatus main body for replenishment of sheets or the like. In the image forming apparatus, there is provided a self-closing device in which, when the sheet feeding cassette is pushed toward the apparatus main body to a certain extent, the sheet feeding cassette is automatically retracted into a sheet feeding position.
By using the self-closing device, a load required to push the sheet feeding cassette by a user is reduced and thus workability is improved, and the sheet feeding cassette is easily positioned at the sheet feeding position. Also, the self-closing device is provided with a buffering member to buffer a biasing force in a direction in which the paper feeding cassette is retracted.
In a case where a spring is used as a biasing member for retracting the sheet feeding cassette, in respect of the spring characteristics, a difference occurs in biasing force at a time of start of retracting and at a time of completion of the retracting. In general, the biasing force at the time of completion of the retracting is weaker than the biasing force at the time of start of retracting. If the biasing force at the time of completion of the retracting is weak, there may be a case in which a problem occurs in positioning precision of the sheet feeding cassette at the sheet feeding position and thus it is preferable that the biasing force at the time of completion of the retracting be as high as possible. In order to reduce the difference in the biasing force and maintain the biasing force at the time of completion of the retracting, there is a need to increase in size of the spring; and however, in that case, there is a problem that a size of the self-closing device is increased and a degree of freedom in design is reduced.
On the other hand, if the biasing force at the time of completion of the retracting is increased, when a user pulls out the sheet feeding cassette at the time of replenishment of sheets or the like, a large force against this biasing force is required, and workability is impaired. Thus, it is difficult to satisfy both of improvement in the user workability and improvement in positioning precision of the sheet feeding cassette, which are contrary to each other.
As a self-closing device using a member other than a spring as a biasing member, there is proposed a self-closing device which retracts a sheet feeding cassette by using a self-weight of a weight. This self-closing device is constructed such that, when the sheet feeding cassette is pushed up to a predetermined position, the sheet feeding cassette is coupled to the weight and then is retracted to the sheet feeding position by the self-weight of the weight, whereas if the sheet feeding cassette is pulled out to the predetermined position, the coupling to the plumb is released, and thus a load required to pull out is reduced.
However, in the self-closing device which retracts the sheet feeding cassette by the self-weight of the weight, a space housing the weight is required, and the self-closing device becomes heavy by the weight and thus there is a problem that a size of the self-closing device is increased.
In accordance with an embodiment of the present disclosure, a self-closing device is configured to retract a unit capable of being pulled out with respect to an apparatus main body, to the apparatus main body. The self-closing device includes a plurality of retracting modules configured to retract the unit from a retracting start position towards a retracting end position. The plurality of retracting modules are provided such that retracting strokes from the retracting start position to the retracting end position partially overlap each other and the retracting start positions are different from each other in the retracting direction.
In accordance with an embodiment of the present disclosure, an image forming apparatus includes a self-closing device. The self-closing device is configured to retract a unit capable of being pulled out with respect to an apparatus main body, to the apparatus main body. The self-closing device has a plurality of retracting modules configured to retract the unit from a retracting start position towards a retracting end position. The plurality of retracting modules are provided such that retracting strokes from the retracting start position to the retracting end position partially overlap each other and the retracting start positions are different from each other in the retracting direction.
The above and other objects, features, and advantages of the present disclosure will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present disclosure is shown by way of illustrative example.
In the following, with reference the drawings, a self-closing device and an image forming apparatus according to an embodiment of the present disclosure will be described.
With reference to
As shown in
In the left part inside the printer main body 2, an exposure device 8 composed of a laser scanning unit (LSU) is arranged and, in the right part, an image forming part 9 is provided. In the image forming part 9, a photosensitive drum 10 as an image carrier is rotatably arranged. Around the photosensitive drum 10, a charger 11, a development unit 12, a transferring roller 13 and a cleaning device 14 are located along a rotating direction (refer to an arrow X in
On a right side of the image forming part 9, a sheet conveying path 17 extending vertically from the sheet feeding cassette 5 to the ejected sheet tray 3 is provided. Along the sheet feeding path 17, a sheet feeding part 18 on a right side of the lower space 2 is provided at an upstream end, a transferring part 19 formed between the photosensitive drum 10 and transferring roller 13 is provided at an intermediate stream portion, a fixing device 20 is provided at a downstream part and a sheet ejecting part 21 is provided at an downstream end. The sheet feeding part 18 is configured to be engaged with the sheet feeding cassette 5 and then to feed the sheet stored in the sheet feeding cassette 5 when the sheet feeding cassette 5 is retracted to the sheet feeding position by the self-closing device 6.
Next, the operation of forming an image by the printer 1 having such a configuration will be described.
When the power is supplied to the printer 1, various parameters are initialized and initial determination, such as temperature determination of the fixing device 20, is carried out. Subsequently, when image data is inputted and a printing start is directed from a computer or the like connected with the printer 1, image forming operation is carried out as follows.
First, the surface of the photosensitive drum 10 is electric-charged by the charger 11. Then, exposure corresponding to the image data on the photosensitive drum 10 is carried out by a laser light P from the exposure device 8, thereby forming an electrostatic latent image on the surface of the photosensitive drum 10. Subsequently, the electrostatic latent image is developed by the development unit 12 into a toner image.
On the other hand, a sheet fed from the sheet feeding cassette 5 by the sheet feeding part 18 is conveyed to the transferring part 19 in a suitable timing for the above-mentioned image forming operation, and then, the toner image on the photosensitive drum 10 is transferred onto the sheet in the transferring part 19. The sheet with the transferred toner image is conveyed to a downstream side in the conveying path 17 to go forward to the fixing device 20, and then, the toner image is fixed on the sheet in the fixing device 20. The sheet with the fixed toner image is ejected to the ejected sheet tray 3 from the sheet ejecting part 21. The toner remained on the photosensitive drum 10 is collected by the cleaning device 14.
Next, the self-closing device 6 will be described with reference to
The self-closing device 6 has left and right retracting modules 30L, 30R. The left and right retracting modules 30L, 30R respectively have: an engaged part 31 provided between a retracting start position P1 and a retracting end position P2 along a retracting direction of the sheet feeding cassette 5; and an engaging part 32 engaging with the engaged part 31 at the retracting start position P1 to be retracted to the retracting end position P2. An interval between the retracting start position P1 and the retracting end position P2 is defined as a retracting stroke S. The left and right retracting modules 30L, 30R have the same retracting stroke S. In the left and right retracting modules 30L, 30R, the engaged parts 31 are provided on the left and right rails 4L, 4R, and the engaging parts 32 are provided on the left and right side faces of the sheet feeding cassette 5.
The left and right retracting modules 30L, 30R are arranged such that the respective retracting strokes partially overlap each other and the retracting start positions P1 are different from each other. Specifically, the retracting start position P1 of the right retracting module 30R is located on a downstream side in the retracting direction from the retracting start position P1 of the left retracting module 30L. Namely, the engaged part 31 of the left retracting module 30L is arranged on a slightly rear side from a center of the left rail 4L, and the engaged part 31 of the right retracting module 30R is arranged near a rear end of the right rail 4R.
By such arrangement, between the retracting start positions P1 of the left and right modules 30L, 30R, a region S1 in which only a retracting force of the left retracting module 30L acts is formed, and between the retracting start position P1 of the left retracting module 30R and the retracting end position P2 of the left retracting module 30L, a region S2 in which the retracting strokes S overlap each other is formed.
In addition, the left retracting module 30L is such arranged that when the engaging part 32 is engaged with the engaged part 31 and then retracted to close to the retracting end position P2 (the position indicated by double-dotted chain line of
Next, with reference to
As shown in
The base member 44 is a rectangular member elongated in the length direction of the right rail 4R and having a width equal to a width of the right rail 4R, and is secured to a bottom face of the right rail 4R by a screw B1. The base member 44 has a central recessed part 44a and an upper recessed part 44b extending in the length direction of the right rail 4R at a center and an upper end in the width direction, respectively. The center recessed part 44a and the upper recessed part 44b each are open toward the outside (outside of the lower space 2a of the printer 2), the center recessed part 44a has a wide rectangular sectional shape, and the upper recessed part 44b has a substantially square sectional shape. On a lower edge of the base member 44, hook portions 44c are formed at front and rear ends.
The center recessed part 44a is formed with a guide hole 51 along the length direction of the right rail 4R. The guide hole 51 has: a linear portion 51a along the length direction of the right rail 4R; and an orthogonal portion 51b curving downward at an angle of 90 degrees from a front end of the linear portion 51a.
The carriage pin 41 is provided on a slider 54 slidably supported in the center recessed part 44a of the base member 44. The slider 54 is a flat, rectangular solid-shaped member elongated in the length direction of the base member 44. At a front end of the slider 54, a stopper 54a extending in a direction crossing the length direction of the slider 54 is formed. On a front end face of the stopper 54a, a plurality of elastic pieces 54b are provided.
On a rear end portion of an inner face of the slide 54, a supporting pin 55 extending in a horizontal direction is erected, and around the supporting pin 55, a piece 56 is turnably supported. The carriage pin 41 is erected on an inner face of the piece 56. The supporting pin 55 and the carriage pin 41 engage with the guide hole 51 with the carriage pin 41 on a front side from the supporting pin 55. Also, the carriage pin 41 protrudes inward from the guide hole 51. If the slider 54 is slid forward along the guide hole 51 with the supporting pin 55 and the carriage pin 41 engaged with the guide hole 51, the carriage pin 41 is engagingly locked with a curved face of the guide hole 51. Afterwards, the piece 56 turns in the clockwise direction of
The slider 54 slides in the length direction of the right rail 4R in the center recessed part 44a of the base member 44 between the retracting start position P1 (refer to
The coil spring 42 is housed in the upper recessed part 44b of the base member 44. A rear end 42a of the coil spring 42 is engagingly locked with a rear end of the upper recessed part 44b, and a front end 42b is engagingly locked with the stopper 54a of the slider 54. The coil spring 42 biases the stopper 54a rearward. That is, the coil spring 42 biases the slider 54 to the retracting end position P2.
The oil damper 43 has a cylinder 43a and a piston 43b. The cylinder 43a is supported by the hook portions 44c of the base member 44 with the piston 43b directing forward. A tip end of the piston 43b is supported by the stopper 54a of the slider 54a. Incidentally, an air damper may be used in place of the oil damper 43.
As shown in
The main slider 61 has a length equal to a length of the right rail 4R, and is secured to the right side face of the sheet feeding cassette 5 so as to correspond to the right rail 4R.
The main slider 61, as shown in
As shown in
With reference to
As shown in
If the sheet feeding cassette 5 is pushed along the left and right rails 4L, 4R (refer to the outline arrow of
If the sheet feeding cassette 5 is further pushed, the inclined portion 65c of the recessed part 65 of the engaging part 32 abuts against the carriage pin 41, and the carriage pin 41 is guided upward along the inclined portion 65c so that the piece 56 turns in the counterclockwise direction of
On the other hand, in the right retracting module 30R, in a middle of retracting of the sheet feeding cassette 5 by the left retracting module 30L, as shown in
Afterwards, as shown in
Incidentally, as shown in
Next, an operation of pulling out the sheet feeding cassette 5 will be described. At the time of starting the pulling out operation, in the left and right retracting modules 30L, 30R, a force against the biasing force of each coil spring 42 of the engaged parts 31 is required. If the sheet feeding cassette 5 is pulled out against the biasing forces of the coil springs 42 of the left and right retracting modules 30L, 30R, the engaging part 32 of the right retracting module 30R reaches close to the retracting start position P1 (refer to
That is, in the region S1 between the retracting start position P1 of the right retracting module 30R and the retracting start position P1 of the left retracting module 30L, only the biasing force of the coil spring 42 of the left retracting module 30L acts on the sheet feeding cassette 5. If the sheet feeding cassette 5 is pulled out against this biasing force, the engaging part 32 of the left retracting module 30L reaches the retracting start position P1 (refer to
As described above, according to the self-closing device 6 of an embodiment of the present disclosure, in the middle of pulling out operation of the sheet feeding cassette 5 within a range of the retracting stroke S of the self-closing device 6, since the engaging part 32 and the engaged part 31 in the right retracting module 30R are disengaged from each other and thus the biasing force in the retracting direction does not act, a maximum value of the pulling out force can be reduced.
Further, a retracting start timing of the right retracting module 30R arranged closer to the sheet feeding device 18 is configured to be later than a retracting start timing of the left retracting module 30L. In this manner, in the right retracting module 30R arranged closer to the sheet feeding device 18, since a retracting force required to retract the sheet feeding cassette 5 toward the sheet feeding position exhibits comparatively significantly at the retracting end position P2, the sheet feeding cassette 5 can be smoothly retracted to the sheet feeding position.
Incidentally, the left and right retracting modules 30L, 30R are not always provided with the oil damper 43. However, if the left retracting module 30L having a longer rectangle stroke is provided with the oil damper 43, an impact buffering effect at the retracting work can be enhanced. As an impact buffering member during the retracting operation, it is preferable to use the oil damper 43 or an air damper which is inexpensive and versatile.
Further, since the left and right retracting modules 30L, 30R are incorporated in the left and right rails 4L, 4R with which the sheet feeding cassette 5 engages, an exclusive space for installing the self-closing device 6 is unrequired. Further, since the left and right retracting modules 30L, 30R are small in size and light in weight, the size and weight of the image forming apparatus 1 can be reduced.
Next, with reference to
In the self-closing device 6 according to the second embodiment, as shown in
As shown in
If the sheet feeding cassette 5 is further pushed, as shown in
Next, an operation of pulling out the sheet feeding cassette 5 will be described. At the time of starting pulling out, the force against the biasing force of the coil springs 42 of the engaged parts 31 of the left and right retracting modules 30L, 30R is required. If the sheet feeding cassette 5 is pulled out against the biasing force of the coil springs 42 of the left and right retracting modules 30L, 30R, the engaging part 32 of the right retracting module 30R reaches the retracting start position P1, and the engaging part 32 and the engaged part 31 are disengaged from each other (refer to
That is, in the region between the retracting start position P1 of the right retracting module 30R and the retracting start position P1 of the left retracting module 30L, only the biasing force of the coil spring 42 of the left retracting module 30L acts on the sheet feeding cassette 5. If the sheet feeding cassette 5 is pulled out against this biasing force, the engaging part 32 of the left retracting module 30L reaches the retracting start position P1 (refer to
As described above, by the self-closing device 6 according to the second embodiment of the present disclosure as well, in the middle of pulling out the sheet feeding cassette 5, the engaging part 32 and the engaged part 31 in the right retracting module 30R are disengaged from each other and the biasing force in the retracting direction does not act so that a maximum value of pulling out force can be reduced.
Incidentally, in the self-closing device 6 of the second embodiment, at least the left retracting module 30L is preferably provided with the oil damper 43. By providing the oil damper 43 in the retracting module having a longer retracting stroke, an impact absorbing effect of the retracting operation is enhanced, and the sheet feeding cassette 5 can be smoothly retracted.
Next, a self-closing device according to a third embodiment, which is a modification example of the second embodiment above, will be described. In the third embodiment, spring constants of the respective coil springs 42 of the left and right retracting modules 30L, 30R are different from each other.
In the second embodiment, a spring constant of the coil springs 42 of the left retracting module 30L having a longer retracting stroke is the same as a spring constant of the coil spring 42 of the right retracting module 30R having a shorter retracting stroke. On the contrary, in the third embodiment, the spring constant of the coil spring 42 of the left retracting module 30L is set to be smaller than the spring constant of the coil spring 42 of the left retracting module 30L in the second embodiment, and the spring constant of the coil spring 42 of the right retracting module 30R is set to be larger than the spring constant of the coil spring 42 of the right retracting module 30R in the second embodiment.
Therefore, in the third embodiment, at the retracting end position P2, a retracting force of the right retracting module 30R is larger than a retracting force of the left retracting module 30L.
Next, with reference to graphs shown in
In the first to third embodiments, if the retracting start positions P1 of the left and right retracting modules 30L, 30R are the same as each other, as indicated by the dashed lines of
However, as in the first to third embodiments, if the retracting start position P1R of the right retracting module 30R is positioned on the downstream side in the retracting direction from the retracting start position P1L of the left retracting module 30L, it is possible to reduce a maximum value of the pulling out force acting on the sheet feeding cassette 5. In this manner, a retracting force required to retract the sheet feeding cassette 5 is obtained, and it is also possible to prevent the maximum retracting force acting on the sheet feeding cassette 5 from being close to the maximum pulling out force Fmax. Also, since an entire stroke for retracting the sheet feeding cassette 5 is not reduced, operability at the time of insertion of the sheet feeding cassette 5 or a damper effect or the like is not degraded.
In the sheet feeding cassette 5 in the embodiments of the present disclosure, since the sheets are housed close to the sheet feeding device 18 in the sheet feeding cassette 5, there may be a case in which a load applied from the sheet feeding cassette 5 on the right rail 4R is larger than that on the left rail 4R. Then, as in the third embodiment, the spring constant of the coil spring 42 of the right retracting module 30R is set to be larger than the spring constant of the coil spring 42 of the left retracting module 30L, whereby the retracting force required to retract the sheet feeding cassette 5 can be appropriately distributed into the left and right retracting modules 30, 30R without increasing the maximum retracting force acting on the sheet feeding cassette 5. In this manner, it is possible to always smoothly retract the sheet feeding cassette 5.
Further, self-closing devices 6 according to fourth and fifth embodiments of the present disclosure will be described with reference to
In the self-closing device according to the fourth embodiment shown in
In the self-closing device according to the fifth embodiment shown in
Thus, the retracting modules 30 do not always need to be provided on the left and right rails 4L, 4R, and can be provided at appropriate positions in consideration of precision of positioning into the sheet feeding position or a layout space or the like of the retracting modules 30. Also, three or more retracting modules 30 may be provided. In addition, a plurality of retracting modules 30 may be integrated into a unit so as to operate independently.
The self-closing device 6, in addition to the sheet feeding cassette 5, is applicable to a variety of units removably provided on the printer main body 2, such as a sheet feeding device 18, an image forming unit 9 (such as a developing device 12 or a transferring unit 19), or a fixing device 20.
The embodiment was described in a case of applying the configuration of the present disclosure to the printer 1. On the other hand, in another embodiment, the configuration of the disclosure may be applied to another image forming apparatus, such as a copying machine, a facsimile or a multifunction peripheral, except for the printer 1.
While the present disclosure has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present disclosure.
Number | Date | Country | Kind |
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2014-143445 | Jul 2014 | JP | national |
2015-137912 | Jul 2015 | JP | national |
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5253015 | Morita | Oct 1993 | A |
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Number | Date | Country |
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2010-202330 | Sep 2010 | JP |
2011-020789 | Feb 2011 | JP |
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Entry |
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The extended European search report issued by the European Patent Office dated Nov. 23, 2015, which corresponds to European Patent Application No. 15176110.3-1705 and is related to U.S. Appl. No. 14/796,863. |
An Office Action issued by the Japanese Patent Office dated Mar. 13, 2018, which corresponds to Japanese Patent Application No. 2015-137912 and is related to U.S. Appl. No. 14/796,863; with English translation. |
Number | Date | Country | |
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20160009512 A1 | Jan 2016 | US |