JP7192386B2 - Document feeder and image forming apparatus provided with same - Google Patents

Description

The present invention relates to a document feeder and an image forming apparatus having the same.

An example of a sheet feeding mechanism and an automatic document feeder is described in Japanese Patent Laying-Open No. 2012-17190 (Patent Document 1).

In a device such as an automatic document feeder that picks up one sheet at a time from a stack of multiple sheet documents and feeds or transports them, even if multiple sheets are fed in order, the paper feed It is necessary to leave an appropriate gap between the sheets to be used. In order to provide such an interval, an electromagnetic clutch or the like is used to control the drive transmission from the motor for a certain period of time after each sheet is fed. For this reason, in a configuration in which an electromagnetic clutch is used in the paper feeding driving section, it is required to hold the pickup roller section at the standby position even when the electromagnetic clutch is in the OFF state during standby. For this reason, a configuration is known in which even when the electromagnetic clutch is in an OFF state, the pickup roller portion is held at the standby position by engaging a lever with the pickup roller portion.

JP 2012-17190 A

When the pickup roller portion is held at the standby position by a lever or the like, a holding force is required to prevent the pickup roller portion from falling even if a small impact is applied to the entire apparatus. In the case of a configuration in which a torque limiter in the paper feed unit exerts a pressing force on the pickup roller, even if the electromagnetic clutch is turned on to lower the pickup roller unit, the torque limiter may slip and the holding by the lever may not be released.

SUMMARY OF THE INVENTION Accordingly, the present invention provides a document document that can reliably lower the pickup roller portion when a driving force is applied while ensuring a sufficient holding force for the pickup roller portion when the pickup roller portion is at the standby position. An object of the present invention is to provide a conveying device and an image forming apparatus having the same.

In order to achieve the above object, the document conveying apparatus according to the present invention includes a first shaft, and a document conveying apparatus supported by the first shaft and rotated around the first shaft to move a stack of sheets from a stack of sheets stacked at a supply location. a pickup roller for picking up sheets one by one; a second shaft arranged parallel to the first shaft; a pick holder that supports a pickup roller; a drive source that rotates the second shaft in a first direction and a second direction that is opposite to the first direction; An upper member arranged above the first shaft, and an engaging member supported by the upper member and capable of being engaged with the pick holder or the first shaft. The pick holder is divided into a first mode in which the pick holder is rotated in the first direction about the second axis and the pickup roller is separated from the sheet bundle, and a mode in which the pick holder is rotated in the first direction about the second axis. A second mode in which the pickup roller presses the sheet bundle by rotating in the second direction is also possible. When the pick holder is in the first mode, the engagement member engages with the pick holder or the first shaft regardless of whether or not the rotation of the second shaft in the first direction is transmitted. maintains the first mode. Further, in this document conveying device, when the pick holder is in the first mode, the rotation of the second shaft in the second direction causes the engagement member to move either the pick holder or the first mode. An engagement releasing portion for releasing engagement with the shaft is provided.

According to the present invention, it is possible to easily switch between the first mode and the second mode depending on which direction of rotation is transmitted to the second shaft 72. Therefore, when the pickup roller portion is at the standby position, the pickup roller portion While ensuring a sufficient holding force for the pickup roller portion, the pickup roller portion can be reliably lowered when a driving force is applied.

1 is a perspective view of an image forming apparatus according to Embodiment 1 of the present invention; FIG. 1 is a sectional view of a document conveying device according to Embodiment 1 of the present invention; FIG. FIG. 2 is a first explanatory diagram of the pick holder and its surroundings of the document feeder according to Embodiment 1 of the present invention; FIG. 10 is a second explanatory diagram of the pick holder and its surroundings of the document feeder according to Embodiment 1 of the present invention; FIG. 4 is an explanatory diagram of a wider range of the pick holder and its surroundings of the document feeder according to Embodiment 1 of the present invention; FIG. 2 is a side view around a pick holder in the first mode of the document conveying device according to Embodiment 1 of the present invention; FIG. 2 is an explanatory diagram of an engaging member and its surroundings of the document conveying device according to Embodiment 1 of the present invention; FIG. 2 is a bottom view of a structure forming part of the document conveying device according to Embodiment 1 of the present invention; FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8; FIG. 9 is a cross-sectional view taken along line XX in FIG. 8; FIG. 10 is a first explanatory diagram of the action of the disengaging portion of the document conveying device according to Embodiment 1 of the present invention; FIG. 10 is a second explanatory diagram of the function of the engagement releasing portion of the document conveying device according to Embodiment 1 of the present invention; 4 is a plan view of a cam included in the engagement release portion of the document conveying device according to Embodiment 1 of the present invention; FIG. FIG. 2 is an oblique bottom view of the pick holder and its peripheral structure of the document feeder according to the first embodiment of the present invention; 1 is a perspective view of a cam and its vicinity of a document conveying device according to Embodiment 1 of the present invention; FIG. FIG. 7 is a conceptual diagram of a document conveying device according to Embodiment 2 of the present invention; FIG. 10 is a side view of a cam and its surroundings of the document feeder according to Embodiment 2 of the present invention; FIG. 10 is an explanatory diagram of how the cam of the document feeder presses the engaging member according to Embodiment 2 of the present invention; FIG. 10 is a perspective view of a cam and its surroundings of the document feeder according to Embodiment 2 of the present invention;

(Embodiment 1)
(composition)
An image forming apparatus and a document conveying apparatus according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 15. FIG.

FIG. 1 shows an image forming apparatus according to this embodiment. The image forming apparatus 801 includes an image forming apparatus main body 201 , an operation section 251 and a document feeder 101 . The document conveying device 101 includes a supply tray 81 , a discharge tray 82 and an upper member 4 . Details of the document conveying device 101 will be described later.

FIG. 2 shows a cross-sectional view of the document conveying device 101 in this embodiment. The document conveying device 101 includes a first shaft 71 , a second shaft 72 and a pick holder 3 . The pick holder 3 is supported by the second shaft 72 and is rotatable around the second shaft 72 . A pickup roller 5 is fixed to the first shaft 71 . When the first shaft 71 rotates, the pickup roller 5 also rotates. A paper feed roller 26 is fixed to the second shaft 72 . When the second shaft 72 rotates, the paper feed roller 26 also rotates. A passage 1 is provided downstream of the pick holder 3 .

FIG. 3 shows an enlarged view of the pick holder 3 and its surroundings. For convenience of explanation, FIG. 3 shows a state in which the sheet bundle 20 is placed on the supply tray 81 . A sheet bundle 20 is obtained by stacking a plurality of sheets 2 . Sheet 2 may be an original. Sheet 2 may be, for example, paper. In FIG. 3 , the pickup roller 5 does not come into contact with the sheet bundle 20 by rotating the pick holder 3 in the first direction 91 . This state is called "first mode". Another mode is shown in FIG. In FIG. 4 , the pickup roller 5 contacts and presses the sheet bundle 20 by rotating the pick holder 3 in the second direction 92 . This state is called "second mode".

A wider range of components around the pick holder 3 is shown in FIG. The drive source 10 may be a motor. The drive source 10 transmits rotation to the second shaft 72 via the drive transmission portion 21 and the electromagnetic clutch 22 . The electromagnetic clutch 22 can connect or disconnect the rotational drive. The rotation transmitted to the second shaft 72 is further transmitted to the first shaft 71 via the drive transmission section 11 . However, the second shaft 72 is provided with a first torque limiter 23 and a second torque limiter 24, so that the second shaft 72 slips when the torque exceeds a certain level in rotation in either direction of the arrows 91e and 92e.

The second shaft 72 rotates in the first direction 91 when the rotating shaft of the drive source 10 rotates in the direction of the arrow 91e and the electromagnetic clutch 22 is turned on. That is, the pickup roller 5 is lifted. In this way, the state shown in FIG. 3 is reached. As a result of the rise of the pickup roller 5, the first torque limiter 23 slips when it comes into contact with the upper member 4, and the pickup roller 5 does not rise any further.

Conversely, the second shaft 72 rotates in the second direction 92 when the rotating shaft of the drive source 10 rotates in the direction of the arrow 92e and the electromagnetic clutch 22 is turned on. That is, the pickup roller 5 descends. In this way, the state shown in FIG. 4 is reached. As shown in FIG. 4, when the pickup roller 5 is pressed against the sheet bundle 20, the second torque limiter 24 slips, and the pickup roller 5 does not descend any further.

FIG. 6 shows a state in which the pickup roller 5 is lifted, that is, a side view of the first mode. FIG. 6 is viewed in the direction of arrow 90 in FIG. The upper member 4 is laterally provided with a projection as a shaft 6c. The engaging member 6 has a C-shaped portion at its upper end. The engaging member 6 is attached to the upper member 4 by surrounding the projection as the shaft 6c with the C-shaped portion of the engaging member 6. As shown in FIG. The engagement member 6 is rotatable about the shaft 6c within a certain angular range. The engaging member 6 is biased by a spring 12. As shown in FIG.

FIG. 7 shows an enlarged view of the tip of the engaging member 6 and its vicinity. The engaging member 6 includes a claw portion 6a. The claw portion 6a has a surface 6b. The engagement member 6 is biased in the direction of arrow 95 by the spring 12 . In the state shown in FIG. 7, the projection 3a of the pick holder 3 rests on the surface 6b of the engaging member 6. As shown in FIG. Thereby, the first mode of the pick holder 3 is maintained.

FIG. 8 shows a bottom view of the structure in which the upper member 4 and the pick holder 3 are combined. FIG. 9 shows a cross-sectional view taken along line IX-IX in FIG. FIG. 10 shows a cross-sectional view taken along line XX in FIG.

As shown in FIG. 11, an engagement release portion 18 is provided. The function of the disengagement portion 18 will be described later.

The arrangement of the document feeder 101 can be expressed as follows.
The document conveying device 101 is supported by the first shaft 71 and the first shaft 71, and rotates around the first shaft 71 to feed out sheets one by one from the sheet bundle 20 stacked on the supply location. 5 , a second shaft 72 arranged parallel to the first shaft 71 , and supported by the second shaft 72 to support at least the first shaft 71 and the pickup roller 5 so as to be rotatable about the second shaft 72 . A pick holder 3 , a drive source 10 for rotating a second shaft 72 in a first direction 91 and a second direction 92 opposite to the first direction 91 , an upper member 4 disposed above the first shaft 71; and an engaging member 6 supported by the upper member 4 and capable of engaging with the pick holder 3 or the first shaft 71. . The pick holder 3 rotates around the second shaft 72 in a first direction 91 to separate the pickup roller 5 from the sheet bundle 20 in a first mode, and in a mode where the pick holder 3 rotates around the second shaft 72 . A second mode in which the pickup roller 5 presses the sheet bundle 20 by rotating in the second direction 92 is also possible. When the pick holder 3 is in the first mode, the engagement member 6 engages with the pick holder 3 or the first shaft 71 regardless of whether or not the rotation of the second shaft 72 in the first direction 91 is transmitted. maintains the first mode. The document conveying device 101 further rotates the second shaft 72 in the second direction 92 when the pick holder 3 is in the first mode, so that the engaging member 6 can move the pick holder 3 or the first shaft. An engagement releasing portion 18 for releasing the engagement with 71 is provided.

The function of the disengaging portion 18 in the document conveying device 101 will be described. As shown in FIG. 11, the disengagement portion 18 includes a projection 14 and a cam 13. As shown in FIG. The protrusion 14 is part of the upper member 4 . As shown in FIG. 11, the cam 13 includes a cam first portion 13a and a cam second portion 13b. When the second shaft 72 rotates in the second direction 92, this rotation is transmitted to the first shaft 71 via the drive transmission section 11, and the first shaft 71 also rotates. This rotation causes cam 13 to rotate as indicated by arrow 96 . When the cam 13 rotates as indicated by an arrow 96 from the state shown in FIG. 11, the state shown in FIG. 12 is obtained. That is, the cam second portion 13b is on the upper side and abuts on the protrusion 14. As shown in FIG. As the cam 13 continues to rotate in the direction of the arrow 96 , the cam 13 pushes up the projection 14 . Since the projection 14 is a part of the upper member 4 , the upper member 4 is pushed up by pushing up the projection 14 . As the upper member 4 is pushed up, the engaging member 6 is displaced upward, so that the protrusion 3a that has been placed on the surface 6b of the engaging member 6 tends to slide off the surface 6b as shown in FIG. At this time, the claw portion 6a of the engaging member 6 is displaced leftward in FIG. As a result, the protrusion 3a is separated from the surface 6b. That is, the holding of the protrusion 3a by the engaging member 6 is finished. In other words, the engagement by the engagement member 6 is released.

For this operation, the cam 13 is provided with a cam first portion 13a having a radius R1 and a cam second portion 13b projecting outward, as shown in FIG. The maximum radius of the cam second portion 13b is R2. The shape of the cam 13 shown here is merely an example, and is not limited to this shape.

FIG. 14 shows the structure of the pick holder 3 and its surroundings as viewed obliquely from below. In FIG. 14, the drive source 10 is schematically displayed.

FIG. 15 shows an enlarged view of the cam 13 and its vicinity. The cam 13 includes a cam first portion 13a, a cam second portion 13b and a weight 13d. The cam 13 is secured to the first shaft 71 by the pin 16 . The pin 16 penetrates through the first shaft 71 . In the cam 13 illustrated here, the weight 13d has a shape that is thicker than the other portions. By increasing the thickness, the part is heavy. The method of forming the weight is not limited to this. In order to form the weight, instead of increasing the thickness, a member made of a material having a higher specific gravity than the material of the other portions may be attached. In order to form the weight, a member made of a material having a higher specific gravity than the material of other portions may be embedded inside the cam without changing the outer shape of the cam.

(action/effect)
In the present embodiment, when the pick holder 3 is in the first mode, the first mode can be maintained by the action of the engaging member 6, and the document conveying device 101 has the second shaft 72 in the second orientation 92. Since the disengagement portion 18 disengages the engagement member 6 by rotating the second shaft 72, the first mode and the second mode can be easily switched depending on which direction of rotation is transmitted to the second shaft 72. can be switched to In other words, it is possible to reliably lower the pickup roller portion when a driving force is applied while ensuring a sufficient holding force for the pickup roller portion when the pickup roller portion is at the standby position. A pickup roller portion corresponds to the pick holder 3 .

As shown in this embodiment, it is preferable that the engaging member 6 is biased in the direction of engaging with the pick holder 3 or the first shaft 71 . By being urged in this way, the engagement of the engaging member 6 can be performed smoothly.

As shown in this embodiment, the disengagement portion 18 includes a cam 13 fixed to the first shaft 71 for rotation with the first shaft 71 , the cam 13 extending from the center of the first shaft 71 . The distance from the center of the first shaft 71 to the outer circumference is a first radius R1, and the distance from the center of the first shaft 71 to the outer circumference is a second radius R2, which is longer than the first radius R1. Preferably, the rotation of the first shaft 71 causes the cam second portion 13b to contact the upper member 4, and further rotation of the cam 13 moves the first shaft 71 away from the upper member 4. By adopting this configuration, the disengagement portion can be realized with a simple structure.

As shown in this embodiment, the upper member 4 has the protrusion 14 arranged on the upper side of the cam 13 so as to approach the cam 13, and the rotation of the first shaft 71 causes the cam second portion 13b to move upward. Preferably, the cam second portion 13b contacts the projection 14 when the cam is closed. The provision of such a projection 14 facilitates the contact of the second cam portion 13b. Moreover, it becomes clear which part of the upper member 4 the cam second part 13b contacts.

Preferably, the cam 13 is held by the first shaft 71 with play in the rotational direction with respect to the first shaft 71 . The state of having play in the direction of rotation means the state of being able to rotate freely within a certain angular range.

As shown in the present embodiment, the cam 13 has a posture in which the cam second portion 13b does not push the upper member 4 when the cam 13 is supported so as to be freely rotatable around the first shaft 71. It is preferable to provide the weight 13d at a position such that it is stabilized at By adopting this configuration, unnecessary contact between the second cam portion 13b and the upper member 4 can be avoided by the action of the weight 13d. The cam 13 is stabilized in a posture in which the weight 13d is as low as possible in a situation where some free rotation is permitted. For example, the posture is such that the weight 13d is directly below. In this stable posture, the second cam portion 13b does not push the upper member 4, so unnecessary pressing of the upper member 4 from the second cam portion 13b can be avoided. For example, the weight 13d may be arranged on the same side as the cam second portion 13b. The weight 13d may be arranged so as to form an angle other than 180° with the second cam portion 13b. For example, if the weight 13d can be positioned directly below due to play in the rotational direction of the cam 13, the second cam portion 13b is positioned on a side other than directly above when the weight 13d is positioned directly below the cam. Unnecessary contact between the second portion 13b and the upper member 4 can be avoided.

(Embodiment 2)
(composition)
A document conveying device according to a second embodiment of the present invention will be described with reference to FIGS. 16 to 19. FIG. The configuration of the document feeder in this embodiment is basically the same as that described in Embodiment 1, but differs in the following points.

FIG. 16 shows the structure of the document feeder according to this embodiment. A view in the direction of arrow 94 in FIG. 16 is shown in FIG. However, in FIG. 17, only the constituent elements related to the explanation are illustrated.

In the document conveying apparatus according to the present embodiment, the disengagement portion includes a cam 13i fixed to the first shaft 71 so as to rotate together with the first shaft 71. As shown in FIG. The cam 13i includes a first cam portion 13ia having a first radius from the center of the first shaft 71 to the outer periphery, and a second radius having a longer distance from the center to the outer periphery of the first shaft 71 than the first radius. and a cam second portion 13ib. The rotation of the first shaft 71 causes the second cam portion 13ib to come into contact with the engaging member 6i, and the cam 13i continues to rotate to push the engaging member 6i. The engagement with the 1 axis 71 is released.

The engaging member 6i is held rotatably about the shaft 6ic. The shaft 6ic is fixed to the upper member 4. As shown in FIG. The engaging member 6i is biased by a spring 12. As shown in FIG. The engaging member 6i has a claw portion 6ia. In the state shown in FIG. 17, the claw portion 6ia is engaged with the projection 3a of the pick holder 3. As shown in FIG. Since the projection 3a of the pick holder 3 is supported by the claw portion 6ia, the pick holder 3 maintains the raised position, that is, the first mode.

FIG. 18 shows a state in which the cam 13i is rotated by rotating the first shaft 71 in FIG. In FIG. 18, by rotating the cam 13i in the direction of the arrow 96, the second cam portion 13ib pushes the engaging member 6i. As shown in FIG. 19, the engaging member 6i is plate-shaped. When the cam second portion 13ib pushes the engaging member 6i, the claw portion 6ia of the engaging member 6i is disengaged from the protrusion 3a as shown in FIG. Since the projection 3a is not supported by the claw portion 6ia, the pick holder 3 can be lowered. The pick holder 3 enters the second mode by descending.

(action/effect)
Also in this embodiment, the same effect as described in the first embodiment can be obtained.

Preferably, the cam 13i is held by the first shaft 71 with play in the rotational direction with respect to the first shaft 71 .

When the cam 13i is supported so as to be freely rotatable around the first shaft 71, the cam second portion 13ib is stabilized in a posture that does not push the engaging member 6i. is preferably provided. By adopting this configuration, unnecessary contact between the second cam portion 13ib and the upper member 4 can be avoided by the action of the weight 13id. The weight 13id may be formed so as to protrude toward the front side of the paper in FIG. FIG. 19 shows that the weight 13id protrudes forward.

An image forming apparatus according to the present invention includes the document conveying device described in any of the above embodiments. For example, the image forming apparatus 801 shown in FIG. 1 is one example.

It should be noted that a plurality of the above embodiments may be appropriately combined and employed.
It should be noted that the above embodiments disclosed this time are illustrative in all respects and are not restrictive. The scope of the present invention is indicated by the claims, and includes all changes within the meaning and range of equivalents to the claims.

1 passage, 2 sheet, 3 pick holder, 3a projection, 4 upper member, 5 pickup roller, 6, 6i engagement member, 6a, 6ia claw portion, 6b surface, 6c, 6ic shaft, 10 drive source, 11, 21 drive Transmission Part 12 Spring 13, 13i Cam 13a, 13ia Cam First Part 13b, 13ib Cam Second Part 13d, 13id Weight 14 Projection 16 Pin 18 Disengagement Part 20 Sheet Bundle 22 Electromagnetic Clutch 23 First torque limiter 24 Second torque limiter 26 Paper feed roller 71 First shaft 72 Second shaft 81 Supply tray 82 Discharge tray 90, 94 Arrows (indicating viewing direction) 91 Third 1 direction, 91e, 91f, 92e, 96 arrow, 92 second direction, 95 arrow (indicating direction of biasing), 101 document feeder, 201 main body of image forming apparatus, 251 operating section, 801 image forming apparatus.

Claims (9)

a first axis;
a pick-up roller that is supported by the first shaft and rotates around the first shaft to pick up sheets one by one from a sheet bundle stacked on a supply location;
a second axis arranged parallel to the first axis;
a pick holder supported by the second shaft and rotatably supporting at least the first shaft and the pickup roller about the second shaft;
a driving source that rotationally drives the second shaft in a first direction and in a second direction opposite to the first direction;
a drive transmission unit that transmits the rotation of the second shaft to the first shaft;
an upper member disposed above the first shaft;
an engaging member supported by the upper member and capable of engaging with the pick holder or the first shaft;
The pick holder rotates in the first direction around the second axis to move the pickup roller away from the sheet bundle in a first mode, and the pick holder rotates about the second axis in the first mode. a second mode in which the pickup roller presses the sheet bundle by rotating in the second direction, and
When the pick holder is in the first mode, the engaging member engages with the pick holder or the first shaft regardless of whether or not rotation of the second shaft in the first direction is transmitted. The first mode is maintained by
moreover,
When the pick holder is in the first mode, the engaging member disengages from the pick holder or the first shaft by rotating the second shaft in the second direction. Equipped with an unmating part ,
the disengagement portion includes a cam fixed to the first shaft so as to rotate with the first shaft;
The cam has a first cam portion having a first radius from the center of the first shaft to the outer circumference, and a second radius having a longer distance from the center of the first shaft to the outer circumference than the first radius. a cam second portion;
The document conveying device according to claim 1, wherein rotation of the first shaft brings the second portion of the cam into contact with the upper member, and further rotation of the cam causes the first shaft to move away from the upper member . 2. The document conveying device according to claim 1, wherein said engaging member is biased in a direction to engage with said pick holder or said first shaft. The upper member has a projection disposed on the upper side of the cam so as to approach the cam, and when the cam second portion moves upward due to the rotation of the first shaft, the cam second portion 3. The document conveying device according to claim 1 , wherein the document conveying device contacts with the . 4. The document conveying device according to claim 1 , wherein said cam is held by said first shaft with play in the rotational direction with respect to said first shaft. The cam is provided with a weight at a position such that when the cam is freely rotatably supported about the first shaft, the cam second portion is stable in a posture that does not push the upper member. 5. The document conveying apparatus according to claim 4 . the disengagement portion includes a cam fixed to the first shaft so as to rotate with the first shaft;
The cam has a first cam portion having a first radius from the center of the first shaft to the outer circumference, and a second radius having a longer distance from the center of the first shaft to the outer circumference than the first radius. a cam second portion;
The rotation of the first shaft causes the second portion of the cam to come into contact with the engaging member, and the cam continues to rotate to push the engaging member. 3. The document conveying device according to claim 1, wherein the engagement with the first shaft is released. 7. The document conveying device according to claim 6 , wherein said cam is held by said first shaft with play in the rotational direction with respect to said first shaft. The cam has a weight at a position such that when the cam is supported so as to be freely rotatable about the first shaft, the cam second portion is stabilized in a posture that does not push the engaging member. 8. The document transport device according to claim 7 , comprising: An image forming apparatus comprising the document conveying device according to claim 1 .

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