JP2007320716A - Paper feeding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeding device performing stable paper feeding by reducing variation of paper feeding pressure and preventing deterioration in the quality of a paper surface caused by constant pressing of a paper feeding roller. <P>SOLUTION: A spring 9 balanced to variation of rotation moment of own weight W of recording paper 6 around a lift plate rotation support shaft 4 of a lift plate 3 by variation of the stacking numbers of the recording paper 6 and setting restoration force in a direction leaving a pick lever 7 from the lift plate 3 is pivotally attached to a pick lever rotation support shaft 8. Thereby, variation of a paper feeding pressure is reduced and the pick lever 7 is left from the lift plate 3 at the time of paper non-feeding. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a paper feeding device, and more particularly to a paper feeding device that conveys paper to an image forming unit of an image forming apparatus such as a printer or a copying machine.

The configuration of the sheet feeding device in an example of the prior art is shown in FIG. 1 showing the configuration of the sheet feeding device according to the embodiment of the present invention, between the portion where the pick lever 7 contacts the lift plate 3 and the bottom surface of the cassette 2. Instead of the pick lever 7, a paper raising spring is provided in a vertical state.
In FIG. 1, a paper cassette 2 for recording and holding recording paper 6 for recording an image is disposed at the bottom of the paper cassette 2, the paper cassette is mounted, and the recording paper 6 is attached to the bottom of the paper cassette 2. Lift plate 3 that can be held in a tilted state, lift plate rotating support shaft 4 that supports the lift plate 3 so as to be rotatable in a direction tilting with respect to the bottom of the paper cassette 2, and stacked and held. A paper feed roller 1 is provided on the uppermost surface of the recording paper 6 so as to be able to contact and separate. The paper lifting spring is disposed in a vertical state between a portion where the pick lever 7 contacts the lift plate 3 and the bottom surface of the cassette 2.
In the prior art, the paper lifting spring pushes up the bottom of the mounted lift plate 3 and inclines around the lift plate rotation support shaft 4 with respect to the bottom of the paper cassette 2 to load the recording. The top surface of the paper 6 is brought into contact with the paper feed roller 1 to pressurize it.

In the paper feeding apparatus configured as described above, in the process of feeding the recording paper 6 to the image forming unit, the lift plate 3 receives the force of the paper lifting spring, and the lift plate rotating support shaft 4 Is rotated in a direction inclined with respect to the bottom of the paper cassette 2. The inclination angle θ of the lift plate 3 with respect to the bottom of the paper cassette 2 changes depending on the number of recording papers 6 stacked. Respect from the lifting plate pivot shaft 4 of the change in the distance L ₂ to the position of the center of gravity of its own weight W corresponding to the number of stacked sheets of the recording paper 6 is a trigonometric function of the inclination angle theta, the paper A force T (corresponding to N in FIG. 1) that the lifting spring pushes the lift plate 3 in a direction perpendicular to the bottom of the paper cassette is substantially directly proportional to the number of the recording paper 6 stacked.

For this reason, the rotational moment TL ₃ of the lifting force T of the lift plate 3 by the paper lifting spring and the rotational moment of the recording paper 6 by its own weight W around the lift plate rotation support shaft 4 of the lift plate 3. balance to fluctuations in the moment of the WL ₂ occurs. As a result, the top surface of the uppermost portion of the recording paper 6 comes into contact with the paper feed roller 1, and the paper feed pressure generated by pressurization also varies. Due to this variation, when the paper feed pressure is reduced, the recording paper 6 is not fed to the image forming unit, and when the paper feed pressure is increased, double feed occurs.

  Further, the paper cassette 2 is fed in a paper feeding device that rotates the lift plate 3 by the pushing force of the paper lifting spring and presses the recording paper 6 loaded on the lift plate 3 against the paper feed roller 1. If the state of being attached to the apparatus main body is continued for a long time, the recording paper 6 is always pressed against the paper feed roller 1, and a pressure contact mark of the paper feed roller 1 is generated on the recording paper 6. The quality of the surface of the recording paper 6 is deteriorated. This degrades the image quality after printing.

As one of the improvement measures, the lift plate 3 on which the recording paper 6 is loaded is swung by the force of the paper lifting spring, and a stopper is provided to make the height of the top surface of the recording paper 6 constant. The feeding roller 1 can be lowered and pressed against the top surface of the uppermost portion of the recording paper 6, and the pressing force of the feeding roller 1 is made constant by applying a torque limiter. By setting it larger than the pushing force against the stopper, even if the number of sheets of recording paper 6 is changed, the force that the paper feed roller 1 presses the uppermost upper surface of the recording paper 6 is not affected. There is a paper feeding device (see, for example, Patent Document 1).
In addition, there is one in which an upward pressing force by a pick lever can be switched between a pressure state and a non-pressure state by an operation lever (see, for example, Patent Document 2).
In addition, there is one in which a necessary pressing force is obtained by adjusting an extension amount of a spring member connected so as to apply an upward pressing force to the pick lever (for example, see Patent Document 3).
Some are controlled so that the upper surface of the paper is raised to an appropriate position by rotation of the lift plate, and the position is controlled (see, for example, Patent Document 4).

JP-A-5-77946 (page 3, FIG. 1) JP-A-8-157079 (page 3-5, FIG. 1-5) JP-A-8-333025 (page 3-4, FIG. 2-5) Japanese Patent Laying-Open No. 2003-201045 (page 6, FIG. 7-8)

  In the conventional apparatus, a difference occurs in the sheet feeding pressure applied to the sheet feeding roller 1 depending on the number of stacked recording papers 6. Further, the change in the own weight W due to the size of the recording paper 6 cannot be handled because the force T by which the paper lifting spring pushes up the lift plate 3 is constant, and a difference occurs in the paper feeding pressure. The change in the paper feed pressure makes the separation and conveyance of the recording paper 6 unstable. In the case of Patent Document 1, for example, the sheet feeding device becomes complicated and the cost increases in order to keep the sheet feeding pressure constant.

  In any of Patent Documents 1 to 4, the paper feed roller 1 and the recording paper 6 cannot be automatically contacted or separated with the paper cassette 2 mounted on the paper feeding device body.

  The present invention enables stable paper feeding by reducing fluctuations in the paper feeding pressure regardless of the recording paper stacking holding state, and even when the paper feed roller faces the recording paper. An object of the present invention is to easily and inexpensively provide a paper feeding device that does not deteriorate the surface of the recording paper by allowing the roller and the recording paper to contact and separate.

  In the paper feeding device according to the present invention, the lift plate capable of stacking and holding the recording paper in an inclined state, the paper feed roller capable of contacting and separating from the surface of the uppermost recording paper stacked and held, and the lift plate The surface of the uppermost recording paper that is stacked and held can be brought into contact with and separated from the paper feed roller by abutting one end against the lift plate and rotating around the other end. A pick lever that pivotably supports the other end of the pick lever, and a spring that constantly generates a biasing force in a direction to separate the pick lever from the lift plate. The paper roller is driven to rotate through a torque limiter, and the pick lever is driven in the direction of contact with the lift plate, and the pick lever is lifted by the biasing force of the spring when not fed. In which was to be away from.

  According to this invention, regardless of the stacked holding state of the recording paper, a stable paper feeding is performed by reducing the fluctuation of the paper feeding pressure, and also in a state where the paper feeding roller faces the recording paper, By enabling the paper feed roller and the recording paper to contact and separate, a paper feeding device that does not deteriorate the surface of the recording paper can be provided easily and inexpensively.

Embodiment 1 FIG.
An embodiment according to the present invention will be described with reference to FIGS. FIG. 1 is a side view showing a dynamic model for the configuration of a sheet feeding device according to an embodiment of the present invention. FIG. 2 is a perspective view showing the configuration of the paper cassette in one embodiment according to the present invention. FIG. 3 is a perspective view showing a main configuration of the sheet feeding device according to the embodiment of the present invention. FIG. 4 is a flowchart of the sheet feeding operation in the embodiment according to the present invention.

In FIG. 1, a paper cassette 2 for recording and holding recording paper 6 for recording an image is disposed at the bottom of the paper cassette 2, the paper cassette is mounted, and the recording paper 6 is attached to the bottom of the paper cassette 2. Lift plate 3 that can be held in a tilted state, lift plate rotating support shaft 4 that supports the lift plate 3 so as to be rotatable in a direction tilting with respect to the bottom of the paper cassette 2, and stacked and held. A paper feed roller 1 is provided on the uppermost surface of the recording paper 6 so as to be able to contact and separate.
Further, the upper surface of the recording paper 6 disposed at the lower part of the lift plate 3 and held on the upper end of the recording paper 6 is held by laminating and holding one end of the lift plate 3 and rotating around the other end. A pick lever 7 that can be brought into and out of contact with the paper roller 1, a pick lever rotating support shaft 8 that is rotatably supported under the lift plate 3, and the other end of the pick lever 7 is pivoted, and the pick A spring 9 that always generates a force in a direction in which the lever 7 is separated from the lift plate 3 is provided.
Further, the paper feed roller 1 and the drive source 10 for driving the pick lever 7, the first transmission gear train 11 for transmitting the rotational force of the drive source 10 to the paper feed roller 1, and the coaxial of the paper feed roller 1. The paper feed roller drive gear 13 fixed on the top and the last gear of the first transmission gear train 11 are supported rotatably so as to be always engaged, and by swinging in the rotation direction of the last gear, A swing idle gear train 12 that can be brought into and out of contact with the roller drive gear 13, a torque limiter 14 that is fixed on the same axis of the paper feed roller 1, and is rotatably supported on the same axis of the paper feed roller 1. A driven gear 16 that engages with the torque limiter 14, a second transmission gear train 15 that transmits the rotational force of the driven gear 16 to the pick lever rotating support shaft 8, and a shaft fixed to the pick lever rotating support shaft 8, Serial second transmission gear train 15 lever drive gear 17 for transmitting the rotational force of the driven gear 16 to the pick lever supporting shaft 8 via is provided.
The driving source 10 biases the torque T through the pick lever rotating support shaft 8 in the direction in which one end of the pick lever 7 is in contact with the lift plate 3 and the recording paper 6 is pressed against the paper feeding roller 1 during paper feeding. Drive with.

  2 to 4, when the drive source 10 is rotating forward, the sheet feeding pressure P generated when the sheet feeding roller 1 comes into contact with the upper surface of the recording paper 6 is the recording paper around the lift plate rotation support shaft 4. 6 is determined by a balance between the rotational moment due to the own weight W of 6 and the rotational moment due to the force N by which the pick lever 7 pushes up the lift plate 3.

The distance L ₁ between the lift plate rotation support shaft 4 and the center of the paper feed roller 1, the distance L ₂ between the lift plate rotation support shaft 4 and the center of gravity of the recording paper 6, the lift plate rotation support shaft 4 and the pick lever 7. The sheet feeding pressure P is determined by P = (NL ₃ −WL ₂ ) / L _{1 based} on the distance L ₃ to the tip of the sheet. By feeding the recording paper 6, the number of stacked sheets and the angle at which the pick lever 7 contacts the lift plate 3 change, so the variables W, L ₂ , N, L ₃ , and L _{1 on} the right side of the above expression change. To do. Thereby, for example, the first and n-th sheet feeding pressure P of the recording paper 6 varies. If the fluctuation range of the paper feed pressure P is large, problems such as a paper feed error or double feed of the recording paper 6 occur.

  The first sheet feeding pressure P1 and the nth sheet feeding pressure Pn of the recording paper 6 are obtained from the above formula, and the sheet feeding pressure fluctuation range δP is obtained by the difference between P1 and Pn. The paper feed pressure P can be stabilized by determining the rigidity of the spring 9 so that δP is minimized.

Specifically, as the paper feed proceeds, the inclination angle φ of the pick lever 7 with respect to the bottom of the paper cassette 2 increases, and the distance L ₄ at which the pick lever rotation support shaft 8 and the pick lever 7 abut against the bottom surface of the lift plate 3. The force N that pushes the lift plate 3 up by the pick lever 7 increases due to the relationship N = T / L ₄ , and the pick lever 7 around the lift plate rotation support shaft 4 pushes up the lift plate 3. rotation moment NL ₃ is increased.

Distance L ₂ between the weight W and the lift plate pivot shaft 4 and the center of gravity of the recording paper 6 of the recording paper 6 stacked on the lifting plate 3 is reduced in accordance with the sheet feeding progresses, the lift plate pivot shaft 4 around torque WL ₂ of the recording paper 6 is reduced.

As a result, the fluctuation range δP of the paper feed pressure P increases as the paper feed proceeds. On the other hand, as the inclination angle φ of the pick lever 7 with respect to the bottom of the paper cassette 2 increases, the torque t of the biasing force applied by the spring 9 in the direction separating the pick lever 7 from the lift plate 3 increases.
Thus, the rotational moment NL ₃ will be reduced in accordance with the paper feed progresses. Accordingly, the rotation moment NL ₂ decreases as the sheet feeding progresses, and the rotation moment NL ₃ also decreases, so that even if the sheet feeding progresses and the stack holding state of the recording paper 6 changes, the recording paper 6 is stacked. The fluctuation range δP of the paper feed pressure P due to the change in the holding state decreases.

  The reduction width of the force N that the pick lever 7 pushes the lift plate 3 up against it is determined by the inclination angle φ with respect to the bottom of the pick lever 7 and the paper cassette 2 and the restoring force due to the torsional rigidity of the spring 9.

  If the restoring force due to the torsional rigidity of the spring 9 is set so that the fluctuation range δP of the paper feed pressure P is minimized, it is possible to cope with fluctuations in the stacking holding state such as a change in the number of sheets or the size of the recording paper 6. The fluctuation range δP of the paper feed pressure P can be reduced to the minimum.

  The paper feeding operation will be described based on the flowchart of FIG.

  When the drive source 10 rotates in the forward direction (step S1), the swing idle gear train 12 and the paper feed roller drive 13 are engaged via the first transmission gear train 11 (step S2), and the paper feed roller 1 is the recording paper. 6 is rotated in the direction in which it is conveyed to the image forming unit (step S3). As the paper feed roller 1 rotates, the driven gear 16 that is coaxially fixed with the paper feed roller 1 rotates, the pick lever 7 is connected via the second transmission gear train 15, and the recording paper 6 is the paper feed roller. 1 is rotated in the direction in which it is pressed against 1 (step S4).

  At the same time, a restoring force is generated in the direction in which the spring 9 fixed on the same axis as the pick lever 7 separates the pick lever 7 from the paper feed roller 1 (step S5). However, the restoring force is made smaller than the braking force for rotating the pick lever 7 when the paper feed roller rotates, so that the recording paper 6 can be pressed against the paper feed roller 1 with an appropriate force.

  The pick lever 7 rotates and the recording paper 6 is pressed against the paper feed roller 1 (step S6).

  The recording paper 6 is conveyed to the apparatus main body image forming unit by the rotation of the paper supply roller 1 (step S7).

  The drive source 10 is reversed (step S8). As a result, the swing idle gear train 12 is separated from the paper feed roller drive gear 13 (step S9).

  Since the feed roller drive gear 13 can no longer transmit the rotational force from the drive source 10, the feed roller drive gear 13 is fixed in a free state in which neither the rotational force nor the braking force acts on the feed roller 1. (Step S10), thereby, the pick lever rotation support shaft to which the rotational force of the drive source 10 has been transmitted via the paper feed roller 1, the driven gear 16, the lever drive gear 17, and the second transmission gear train 15 4 is in a free state in which neither rotational force nor braking force is transmitted (step S11), and the pick lever 7 supported by the pick lever rotation support shaft 4 is separated from the lift plate 3 by the restoring force of the spring 9 (step S12).

  Thereby, the recording paper 6 is separated from the paper feed roller 1 (step S13).

  In the embodiment according to the present invention, the recording paper 6 is brought into contact with the paper feed roller 1 only by a paper lifting spring, and the drive source 10 is rotated forward (as compared with the prior art in which the paper feed pressure is increased). 3), the pick lever 7 (see FIG. 1) rotates at one end to come into contact with the lift plate 3, and the surface of the uppermost recording paper 6 that is stacked and held is pressed against the paper feed roller 1. Since the torque limiter is idled at this point, the rotational moment around the lift plate rotation support shaft 4 where the pick lever 7 pushes up the lift plate 3 is stabilized as compared with the conventional paper lifting spring.

Further, the pick lever 7 is lifted from the lift plate 3 so as to balance with the fluctuation of the rotational moment of the weight W of the recording paper 6 around the lift plate rotation support shaft 4 of the lift plate 3 due to the change of the number of the recording paper 6 loaded. A spring 9 (see FIG. 1) whose restoring force is set in the separating direction is fixed to the pick lever rotation support shaft 4 so that the pick lever 7 can be lifted regardless of the number of recording papers 6 or the size. It is possible to stabilize the force that pushes up 3 and to reduce fluctuations in the sheet feeding pressure.
Thereby, stable paper feeding is possible.

Further, when the drive source 10 is rotated in the reverse direction, the swing idle gear train 12 (see FIG. 3) is separated from the paper feed roller drive gear 13 (see FIG. 3), and the feed roller 1 is free of rotational force and braking force. Therefore, the pick lever that has been transmitted with the rotational force of the drive source 10 via the driven gear 16 (see FIG. 3), the lever drive gear 17 and the second transmission gear train 15 (see FIG. 3). In the rotating support shaft 4, the pick lever 7 is separated from the lift plate 3 by the restoring force of the spring 9.
For this reason, when the paper cassette 1 is mounted on the main body of the paper feeding device, the paper for recording is generated when the paper feeding roller 1 and the recording paper 6 are separated from each other and are always pressed against the paper feeding roller 1 when not feeding paper. 6 quality degradation can be prevented.

(1A) According to the embodiment of the present invention, the lift plate 3 that can be laminated and held with the recording paper 6 inclined, and the surface of the uppermost recording paper 6 that is laminated and held can be separated from the surface. The surface of the uppermost recording paper 6 which is disposed under the paper feed roller 1 and the lift plate 3 and which is laminated and held by abutting one end on the lift plate 3 and rotating around the other end. A pick lever 7 that can be moved toward and away from the paper feed roller 1, a pick lever rotation support shaft 8 that rotatably supports the other end of the pick lever 7, and the pick lever 7 are separated from the lift plate 3. A spring 9 that constantly generates a biasing force in the direction is provided, and the paper feeding roller 1 is driven to rotate through a torque limiter 14 by rotation of the driving source 10 in one direction during paper feeding, and the pick lever 7 is moved to the lift plate 3. What The spring 9 is driven in one direction in the abutting direction, and the pick lever 7 is released from the driving state without driving the pick lever 7 by rotation in the other direction of the driving source 10 when paper is not fed. Since the pick lever 7 is separated from the lift plate 3 by the urging force, the paper feeding pressure is reduced and the paper is stably fed regardless of the change in the holding state of the recording paper 6. Further, even when the paper feed roller 1 is opposed to the recording paper 6, the surface of the recording paper 6 can be deteriorated by allowing the paper feed roller 1 and the recording paper 6 to contact and separate. It is possible to easily and inexpensively provide a paper feeding device that is not present.

(1B) According to the embodiment of the present invention, in the configuration according to the item (1A), the restoring force of the spring 9 is a fluctuation range of the pressure contact force of the paper feed roller 1 with respect to the top surface of the recording paper 1. Since the restoring force of the spring is set so as to be small regardless of the change in the lamination holding state of the recording paper 6 at the time of paper feeding, regardless of the change in the lamination holding state of the recording paper 6, Stable paper feeding is possible with minimal fluctuations in paper feeding pressure, and the paper feeding roller 1 and the recording paper 6 can be contacted and separated even when the paper feeding roller 1 faces the recording paper 6. By doing so, it is possible to easily and inexpensively provide a paper feeding device that does not deteriorate the surface of the recording paper 6.

(1C) According to the embodiment of the present invention, in the configuration of the item (1A) or the item (1B), the paper cassette 2 in which the lift plate 3 that holds the recording paper 6 in a stacked manner is disposed at the bottom. In the state where the paper cassette 2 is mounted on the paper feeder main body and the recording paper 6 stacked and held on the lift plate 3 is opposed to the paper feed roller 1, the pick lever 7 is moved up and down, Since the recording paper 6 laminated and held on the lift plate 3 can be brought into contact with and separated from, the sheet feeding pressure fluctuation is minimized and stable regardless of the change in the lamination holding state of the recording paper 6. Even when the paper cassette 2 is mounted on the main body of the paper feeding apparatus and the paper feeding roller 1 is opposed to the recording paper 6, the paper feeding roller 1 and the recording paper can be used. By enabling 6 separable, it is possible to provide a sheet feeding apparatus without degrading the surface of the recording paper 6 easily and inexpensively.

(1D) According to the embodiment of the present invention, in the configuration in any one of the items (1A) to (1C), the driving for rotating the paper feed roller 1 and one end of the pick lever 7 are Since the rotation driving is performed by the common driving source 10, the recording paper has a simple configuration in which the feeding roller 1 and the pick lever 7 are driven by the common driving source 10. Regardless of the change in the stacking holding state of 6, stable paper feeding is performed by minimizing fluctuations in the paper feeding pressure, and the paper cassette 2 is mounted on the paper feeding device body and the paper feeding roller 1 is attached to the recording paper 6. Even in a state of being opposed to the paper, the paper feed roller 1 and the recording paper 6 can be contacted and separated, thereby providing a paper feeding device that does not deteriorate the surface of the recording paper 6 easily and inexpensively. It is possible.

(1E) According to the embodiment of the present invention, the paper cassette 2 for holding the recording paper 6 is held on the bottom of the paper cassette 2, the recording paper 6 is mounted, and the recording paper 6 Lift plate 3 that can be stacked and held in a state where the sheet is inclined with respect to the bottom of the paper cassette 2, paper feed roller 1 that can contact and separate from the surface of the uppermost recording paper 6 that is stacked and held, and the lift plate 3, a pick that is disposed in the lower part of 3 and makes the surface of the uppermost recording paper 6 that is stacked and held by coming into contact with and swinging against the lift plate 3 to come into contact with and separate from the paper feed roller 1. A lever 7 is rotatably supported under the lift plate 3, and is attached to a pick lever rotating support shaft 8 on which the pick lever 7 is pivoted, in a direction to separate the pick lever 7 from the lift plate 3. A spring 9 that constantly generates force, a drive source 10 that drives the paper feed roller 1 and the pick lever 7, a first transmission gear train 11 that transmits the rotational force of the drive source 10 to the paper feed roller 1, The feed roller drive gear 13 that is fixed on the same axis as the feed roller 1 and the last gear of the first transmission gear train 11 are supported so as to freely rotate and swing in the rotational direction of the last gear. By moving, the oscillating idle gear train 12 that can be brought into and out of contact with the roller drive gear 13, the torque limiter 14 that is axially fixed on the paper feed roller 1, and the coaxial on the paper feed roller 1 A driven gear 16 that is rotatably supported and engages with the torque limiter 14, a second transmission gear train 15 that transmits the rotational force of the driven gear 16 to the pick lever rotation support shaft 8, and the pick lever rotation In the sheet feeding device having a lever driving gear 17 which is fixed to the shaft 8 and transmits the rotational force of the driven gear 16 to the pick lever rotating support shaft 8 through the second transmission gear train 15, the driving source 10, the swing idle gear train 12 meshes with the roller drive gear 13, the paper feed roller 1 rotates, the pick lever 7 rotates to abut against the lift plate 3, and is held in layers. When the uppermost surface of the uppermost recording paper 6 is pressed against the paper feed roller 1, the torque limiter 14 idles and feeds the upper surface of the uppermost recording paper 6 held stacked. When the pressure contact force of the roller 1 is stable and the drive source 10 is reversely rotated, the swing idle gear train 12 is separated from the paper feed roller drive gear 13, and the paper feed roller 1 has a rotational force. Since the pick lever 7 is released from the driving state and the pick lever 7 is separated from the lift plate 3 by the restoring force of the spring 9, the braking force is not applied. The paper feed roller 1 is driven and the pick lever 7 is rotated through a gear by forward rotation, and the paper feed roller 1 is inactivated by reverse rotation of the drive source and is restored by the restoring force of the spring. The pick lever 7 is separated from the lift plate 3 to perform stable paper feeding with minimal fluctuations in the paper feeding pressure regardless of the change in the stacking holding state of the recording paper 6. Even in a state where the paper roller 1 faces the recording paper 6, the surface of the recording paper 6 can be deteriorated by allowing the paper feeding roller 1 and the recording paper 6 to contact and separate. Gastric feeding device can be provided easily and inexpensively.

It is a side view which shows the dynamic model about the structure of the paper feeder in one Embodiment by this invention. It is a perspective view which shows the structure of the paper cassette in one Embodiment by this invention. 1 is a perspective view illustrating a configuration of a main part of a sheet feeding device according to an embodiment of the present invention. It is a flowchart of the paper supply operation | movement in one Embodiment by this invention.

Explanation of symbols

1 paper feed roller, 2 paper cassette, 3 lift plate, 4 lift plate rotation support shaft, 5 paper lifting spring, 6 recording paper, 7 pick lever, 8 pick lever rotation support shaft, 9 spring, 10 drive source, 11 1 transmission gear train, 12 swing idle gear train, 13 paper feed roller drive gear, 14 torque limiter, 15 second transmission gear train, 16 driven gear, 17 lever drive gear.

Claims (5)

  A lift plate capable of stacking and holding the recording paper in an inclined state, a feed roller capable of contacting and separating from the surface of the uppermost recording paper stacked and held, and the lift plate disposed below the lift plate A pick lever that allows the surface of the uppermost recording paper, which is laminated and held, to come in contact with and separate from the paper feed roller by abutting one end to the other end and rotating about the other end A pick lever rotating support shaft that rotatably supports the end, and a spring that constantly generates an urging force in a direction to separate the pick lever from the lift plate, and rotate the paper feed roller via a torque limiter during paper feeding. And driving the pick lever in a contact direction with the lift plate, and separating the pick lever from the lift plate by a biasing force of the spring when not feeding. Sheet feeder that.   The restoring force of the spring is set so that the fluctuation range of the pressure-contact force of the paper feed roller with respect to the uppermost upper surface of the paper for recording is made small regardless of the recording paper laminated holding state at the time of paper feeding. The paper feeding device according to claim 1.   A paper cassette having the lift plate for laminating and holding the recording paper disposed at the bottom, the paper cassette being mounted on the paper feeder main body and the recording paper being laminated and held on the lift plate being fed to the paper feed roller; 3. The sheet feeding device according to claim 1, wherein the pick lever is moved up and down in a state of being opposed to the sheet, and the recording paper stacked and held on the lift plate can be contacted and separated. .   4. The sheet feeding device according to claim 1, wherein driving of the sheet feeding roller and driving of the pick lever are executed by a common driving source. 5.   A paper cassette for stacking and holding recording paper, disposed at the bottom of the paper cassette, mounted with the recording paper, and capable of stacking and holding the recording paper in an inclined state with respect to the bottom of the paper cassette A lift plate, a feed roller that can be brought into contact with and separated from the surface of the uppermost recording paper that is stacked and held, and a lower portion of the lift plate are arranged so that one end abuts the lift plate and rotates around the other end. A pick lever that enables the surface of the uppermost paper held stacked by moving to contact and separate from the paper feed roller, and is supported rotatably under the lift plate, and the other end of the pick lever A pick lever rotating support shaft that is fixed to the shaft, a spring that constantly generates force in a direction in which the pick lever is moved away from the lift plate, and the paper feed roller and the pick lever are driven. A power source, a first transmission gear train for transmitting the rotational force of the drive source to the paper feed roller, a paper feed roller drive gear fixed on the same axis of the paper feed roller, and the first transmission gear train A swing idle gear train that is rotatably supported so as to always mesh with the last gear and swings in the rotation direction of the last gear, and can be brought into contact with and separated from the roller drive gear. A torque limiter pivoted on the upper side, rotatably supported on the same axis as the paper feed roller, and engaged with the torque limiter, and a rotational force of the driven gear is transmitted to the pick lever rotation support shaft. Paper feed having a second drive gear train and a lever drive gear which is fixed to the pick lever rotation support shaft and transmits the rotational force of the driven gear to the pick lever rotation support shaft via the second transmission gear train Equipment When the drive source rotates in the forward direction, the swing idle gear train meshes with the roller drive gear, the paper feed roller rotates, the pick lever rotates to abut against the lift plate, and is stacked and held. When the surface of the uppermost recording paper is pressed against the paper feed roller, the torque limiter idles and the pressure of the paper feed roller pressed against the upper surface of the uppermost recording paper held in a stacked state is reduced. When the drive source is reversely rotated, the oscillating idle gear train is separated from the paper feed roller drive gear, and the feed roller is in a free state in which neither a rotational force nor a braking force is applied. The sheet feeding device, wherein the pick lever is separated from the lift plate by a restoring force.

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