JP4612896B2 - Sheet feeding apparatus and recording apparatus - Google Patents

Description

  The present invention uses, in an image recording apparatus such as a printer, a copying machine, or a facsimile machine, a sheet feeding apparatus for feeding a recording sheet stacked on a sheet storage unit to an image forming unit, and the sheet feeding apparatus. The present invention relates to a recording apparatus.

  A recording apparatus having functions such as a printer, a copying machine, and a facsimile is configured to record an image (including characters and symbols) on a recording sheet based on image information by a recording head. As a recording sheet which is a recording medium, sheet materials of various materials such as paper, cloth, plastic sheet, and OHP sheet can be used. There are two types of recording systems in this recording apparatus: a serial type and a line type. The serial type is a method of recording an image while alternately repeating main scanning for moving the recording head along the recording medium and paper feeding (sub scanning) of the recording medium. On the other hand, in the line type, by using a long recording head extending in the width direction of the recording medium, an image is recorded only by paper feeding (sub scanning) of the recording medium while recording one line at a time. It is a method.

  The recording apparatus is provided with a sheet feeding device for feeding recording sheets stacked on a sheet storage unit such as a cassette one by one toward the image forming unit. 6 is a longitudinal sectional view of a conventional sheet feeding apparatus, and FIG. 7 is a perspective view of the sheet feeding apparatus of FIG. 6 and 7, a plurality of recording sheets 111 can be stored in a stacked state in a detachable cassette 101 which is a box-shaped sheet storage unit. A paper feed roller 102 as a feeding unit is disposed below the cassette, and this paper feed roller is pressed against the stacked recording sheets from the lower side in the illustrated example. By rotating the paper feed roller in the direction of the arrow by the driving means, the recording sheets 111 are separated one by one and sent out in the direction of arrow S and fed. The cassette 101 can be attached to and detached from the recording apparatus along the guide member (not shown) from the front surface or the side surface as indicated by an arrow AB or an arrow CD in FIG.

  On the upper side of the cassette 101, a pressure contact plate 104, which is a pressure contact means for pressing the stored recording sheet 111 against the paper feed roller 102, is provided. The pressure contact plate 104 is pressed against the recording sheet from above by a compression spring 104 which is an elastic member. Such a press contact means aims to stabilize the feeding operation, and is to secure a stable frictional force between the recording sheet and the paper feed roller during the feeding operation. The magnitude of this frictional force is set to a value larger by a predetermined amount than the frictional force between the recording sheets. In this embodiment, the spring 104 as an elastic member is provided on the pressure contact plate 103 side. However, this may be provided on the paper feed roller 102 side, or may be provided on both. When the user replenishes the recording sheet, the user pulls out the cassette 101 from the sheet feeding apparatus and replenishes it.

When feeding the recording sheet, the sheet feeding roller and the recording sheet must be in a pressure contact state. However, in the pressure contact state, a large force is required to pull out the cassette 101, which makes it difficult to pull out. In addition, there is a high possibility that the recording sheet jams and is jammed when being pulled out. Conversely, when the cassette 101 is mounted, if the recording sheet and the paper feed roller are in a position where they interfere with each other, similarly, it is difficult to mount the recording sheet, and the possibility that the recording sheet jams increases. Therefore, in order to eliminate such inconvenience, at the time of pulling out the cassette, at least one of the paper feed roller and the pressure contact plate is separated to the retracted position. As an example, Patent Document 1 discloses a separation mechanism for retracting a paper feed roller.
Japanese Patent No. 3302670

  However, in the conventional sheet feeding apparatus as shown in FIGS. 6 and 7, since the spring 104 is disposed outside the cassette 101 or the like, the sheet feeding apparatus has a size (dimension X) of the spring 104. As a result, it becomes larger and the device becomes larger. Further, in order to secure a stable pressure contact force from when the recording sheets in the cassette are fully loaded to when they are loaded, it is necessary to make the spring constant as small as possible. For this purpose, it is necessary to design the overall length of the spring to be long. For this reason, in the conventional example in which the spring is arranged on the outside, there is a disadvantage that the X dimension shown in the drawing becomes larger and the size of the apparatus is increased if an attempt is made to improve the reliability by a stable pressure contact operation.

  The present invention has been made in view of such technical problems. SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet feeding apparatus capable of arranging an elastic means for urging the pressure contact means for pressing the recording sheet against the feeding means in an optimum posture for realizing downsizing of the apparatus, and A recording device is provided. Also provided are a sheet feeding apparatus and a recording apparatus capable of stabilizing the feeding operation and improving the reliability while reducing the size of the apparatus.

The present invention provides a sheet storage unit capable of stacking recording sheets, a feeding unit for feeding the recording sheets stacked on the sheet storage unit, and a recording sheet stacked on the sheet storage unit against the feeding unit. A sheet feeding apparatus including pressure contact means for performing the above operation.
The sheet feeding apparatus according to the present invention includes a first lever member that can rotate about an axis parallel to the recording sheets stacked on the sheet storage means, and an axis that is parallel to the rotation center of the first lever member. And a second lever member that is rotatable as a center.
Furthermore, the sheet feeding apparatus according to the present invention includes an elastic member extending in a direction parallel to the recording sheets stacked on the sheet storage unit.
The first lever member extends in parallel with the recording sheet and can press the pressure contact means, and the other lever that extends in a direction intersecting the recording sheet and has a biased portion. Part.
The second lever member has one lever portion that acts on the biased portion of the first lever member and the other lever portion that extends in a direction intersecting the recording sheet.
Therefore, by applying the spring force of the elastic member to the other lever portion of the second lever member, the first lever member is urged to rotate via the second lever member.
By the biasing force of the first lever member, the pressure contact means is pressed by one lever portion of the first lever member, so that the recording sheet is pressed against the feeding means by the pressure contact means.

  Another sheet feeding apparatus according to the present invention includes sheet storage means capable of stacking recording sheets, and feeding means for feeding the recording sheets stacked on the sheet storage means. A pressure contact member configured to press the recording sheet stacked on the sheet storage unit rotatable about an axis parallel to the recording sheet stacked on the sheet storage unit against the feeding unit; A first lever member rotatable integrally with the pressure contact member about the shaft; and an elastic member disposed in parallel with the recording sheet along a side portion of the sheet storage unit. Further, the elastic member is rotated and urged by the elastic force of the elastic member, contacts the first lever member, and the elastic member exerts the elastic force of the first lever member so that the press contact member presses the recording sheet. It has the 2nd lever member which carries out rotation energization.

  According to the present invention, a sheet feeding apparatus capable of arranging the elastic means for biasing the pressure contact means for pressing the recording sheet against the feeding means in an optimum posture for realizing downsizing of the apparatus, and A recording device is provided. Further, by making the elastic means sufficiently long without causing an increase in size, a stable pressure contact force can be obtained regardless of the stacked amount of recording sheets. Provided are a sheet feeding apparatus and a recording apparatus capable of stabilizing the feeding operation and improving the reliability while reducing the size of the apparatus.

  Embodiments of the present invention will be specifically described below with reference to the drawings. Note that the same reference numerals denote the same or corresponding parts throughout the drawings. FIG. 5 is a longitudinal sectional view showing an embodiment of a recording apparatus suitable for using the sheet feeding apparatus according to the present invention. FIG. 5 exemplifies a thermal transfer recording apparatus that records by transferring ink on an ink ribbon onto a recording sheet by a thermal head. In FIG. 5, the cassette 1 containing the recording sheet 11 is detachably attached to the main body of the recording apparatus 100. A paper feed roller 2 is disposed below the cassette 1. Further, an unwinding side ink ribbon storage portion 21 and a winding side ink ribbon storage portion 22 are mounted below the cassette 1. By rotating the winding shaft 23, the ink ribbon 25 on the supply shaft 24 is wound on the winding shaft 23.

  At the time of image recording, the uppermost sheet of the recording sheet 11 in the cassette 1 serving as a sheet storage unit is separated and fed by a sheet feeding roller 2 serving as a feeding unit. The recording sheet to be fed is conveyed along the U-turn conveyance path 27 having the conveyance guide 26 to the image forming unit 30 between the recording head (thermal head) 28 and the platen roller 29. The cassette 1 is detachably positioned at a predetermined position of the recording apparatus. In the vicinity of the cassette 1, a sheet feeding device 50 according to the present invention including the cassette 1 and the sheet feeding roller 2 is configured. In the image forming unit 30, the recording sheet 28 and the ink ribbon 25 are conveyed by the conveying rollers 31, 31 while being pressed between the recording head 28 and the platen roller 29. An image is formed by melting and transferring the ink applied to the ink ribbon onto the recording sheet by the heating element on the recording head. In the case of an ink ribbon for color recording, inks of a plurality of colors such as yellow, magenta, and cyan are repeatedly applied with a certain length. A color image is formed by reciprocating the image forming section 30 by the number of colors of the recording sheet and transferring the respective colors in an overlapping manner.

  FIG. 1 is a side view of an embodiment of a sheet feeding apparatus according to the present invention. FIG. 2 is a perspective view of the sheet feeding apparatus of FIG. 1 and 2, a plurality of recording sheets 11 can be stored in a stacked state in a cassette 1 which is a sheet storage means. The cassette 1 can be taken out from or attached to the recording apparatus 100 along the guide member (not shown) from the front or side as indicated by the arrow AB or the arrow CD in FIG. Below the cassette 1, there is provided a feeding means 2 for acting on the lower surface of the recording sheet in the cassette to feed and feed the recording sheets one by one. The feeding means 2 is composed of a paper feed roller that is rotationally driven in the direction of the arrow in the drawing at the time of feeding. The paper feed roller 2 is rotatably supported on the chassis (or frame) of the recording apparatus 100. On the upper side of the cassette 1 is provided a pressure contact plate 3 which is a pressure contact means capable of switching between a feeding position where the recording sheet 11 in the cassette is pressed against the sheet feeding roller 2 and a retracted position away from the recording sheet in the cassette. It has been. The press contact plate 3 may be attached to the cassette 1 or may be attached to the recording apparatus side.

  Near the cassette 1 is provided a first lever member 4 that is pivotally supported about a shaft 4a parallel to the recording sheet 11 and intersecting the sheet conveying direction. Also, in the vicinity of the cassette 1, a second lever member 5 that is pivotally supported around a shaft 5 a that is parallel to the recording sheet 11 and intersects the sheet conveying direction is provided. . These shafts 4a and 5a are provided in the vicinity of a cassette mounting portion such as a chassis (or a frame) of the recording apparatus. The first lever member 4 is composed of lever portions 4b and 4c provided on both sides of the rotation shaft 4a as an intermediate. The second lever member 5 is composed of lever portions 5b and 5d provided on both sides of the rotation shaft 5a.

One lever portion 4b of the first lever member 4 extends in parallel with the stacked recording sheets, and can act so as to press and urge the pressure contact plate 3 in the sheet pressure contact direction at its front end portion 4f. . Further, the other lever portion 4c of the first lever member 4 extends in a direction intersecting with the stacked recording sheets (for example, a vertical direction), and is energized to receive a pressing force described later in the vicinity of the lower end thereof. Part 4d.
One lever portion 5b of the second lever member 5 has a pressing portion 5c that extends downward from the rotating shaft 5a and that can act to press the biased portion 4d of the first lever member. . Further, the other lever portion 5d of the second lever member 5 extends upward from the rotation shaft 5a in a direction (for example, a vertical direction) intersecting with the stacked recording sheets.

  On the side of the cassette 1, a spring 6 is stretched as elastic means extending in a direction parallel to the stacked recording sheets 11. As the illustrated elastic means 6, a tension coil spring is used. One end of the spring 6 is connected by being engaged with an engaging portion 7 provided at a fixed position of the recording apparatus. The engaging portion 7 can be formed by, for example, a pin-shaped protrusion. The other end of the spring 6 is connected by being engaged with an actuated portion 5 e provided at the upper end of the other lever portion 5 d of the second lever member 5. The actuated portion 5e can be formed by an engagement hole, for example.

  With the above configuration, a predetermined couple force (rotating biasing force) about the shaft 5a is applied to the second lever member 5 by the spring force of the spring 6, and the shaft is applied to the first lever member 4 by this couple force. A second couple (rotating biasing force) centered on 4a can be applied. Then, a downward pressing urging force is applied to the pressure contact plate 3 by the distal end portion 4f of the first lever member by the second couple. The recording sheet 11 in the cassette 1 is pressed against the paper feed roller 2 by this pressing biasing force. Therefore, the recording sheet can be fed by the frictional force between the sheet feeding roller and the recording sheet by rotationally driving the sheet feeding roller in the direction indicated by the arrow. In this case, the frictional force between the paper feed roller and the recording sheet is set to be larger by a predetermined amount than the frictional force between the recording sheet and the recording sheet. As a result, the recording sheets in the cassette are separated one by one and fed toward the image forming unit 30. The fed recording sheet is further conveyed through the image forming unit by a conveying unit having a conveying roller 31.

  FIG. 3 is a side view showing a transmission state of the elastic force acting on the pressure contact means 3 from the elastic means 6 in the sheet feeding apparatus of FIG. FIG. 4 is a perspective view showing a state of transmission of elastic force acting on the pressure contact means 3 from the elastic means 6 in the sheet feeding apparatus of FIG. 3 and 4, a predetermined tensile force F1 is generated in the spring 6 by setting the spring constant of the spring 6 and the amount of displacement in the attached state. Due to this tensile force F1, a couple (rotation biasing force) N1 acts on the second lever member 5 around the shaft 5a. Due to the couple N1, a pressing force (pressing biasing force) F2 is applied from the pressing portion 5c of the second lever member to the biased portion 4d of the first lever member. Due to this pressing force F2, a couple (rotation biasing force) N2 acts on the first lever member 4 around the shaft 4a. Due to this couple N2, a downward pressing force (pressing urging force) F3 acts on the pressure contact plate 3 from the distal end portion 4f of the first lever member. The recording sheet 11 stored in the cassette 1 is pressed against the paper feed roller 2 by the force F3 by the pressure contact plate 3 biased downward by the pressing force F3.

  According to the embodiment of the sheet feeding device 50 described above, a pressure contact force can be applied to the pressure contact plate 3 by the spring 6 that is mounted in parallel and flat with the recording sheet 11. In other words, the spring 6 attached in a flat and flat state parallel to the recording sheet 11 along the side portion of the cassette 1 presses the pressure contact force required to feed the recording sheet 11 from the cassette 1 by the paper feed roller 2. It can be applied to the plate 3. In the present embodiment, the application of such a pressure contact force is realized through the two lever members 4 and 5. According to this embodiment, since the press contact plate 3 can be pressed by the spring 6 extending in parallel with the recording sheet 11 along the side portion of the cassette 1, the press contact plate is directly pressed as in the conventional example. The height of the sheet feeding device can be reduced as compared with the conventional example using a spring that performs this. As a result, it is possible to reduce the size of the sheet feeding device 50 and consequently the size of the recording device 100.

  Further, since the spring 6 can be arranged in the length direction of the stacked recording sheets 11, the total length of the spring can be made sufficiently long without impairing the downsizing of the apparatus. Therefore, by selecting the spring constant of the spring 6 to a sufficiently small value without impairing the miniaturization of the apparatus, the press contact force can be maintained at a substantially constant appropriate value regardless of the recording sheet stacking amount. Thus, the recording sheet can always be pressed against the paper feed roller 2 with a stable pressing force, and a stable feeding operation can always be maintained. Therefore, according to the embodiment described above, there is provided a sheet feeding apparatus and a recording apparatus in which the elastic means 6 for urging the pressure contact means 3 can be arranged in an optimum posture for realizing downsizing of the apparatus. Is done. A long elastic means having a small spring constant can be used while realizing miniaturization of the apparatus. As a result, the apparatus can be reduced in size, and at the same time, the press contact operation for pressing the recording sheet 11 against the feeding device 2 by the press contact device, and the stabilization of the recording sheet feeding operation by the feed device and the improvement of the reliability can be achieved. A sheet feeding apparatus and a recording apparatus capable of performing the above are provided. That is, a sheet feeding apparatus and a recording apparatus that can achieve both improvement in reliability and downsizing are provided.

  In the above-described embodiment, the spring force of the spring 6 is directly applied to the second lever member 5, but this can be achieved by indirectly operating the second lever member 5 via another member. Even if the lever member is configured to generate the couple N1, the same effect can be obtained. In the above-described embodiment, the sheet feeding roller 2 is disposed below the cassette 1, and the lower surface of the recording sheet 11 in the cassette is pressed against the sheet feeding roller by the pressing plate 3 disposed above the cassette. did. In contrast to this configuration, the present invention can be similarly applied to a sheet feeding apparatus in which the vertical relationship between the sheet feeding roller and the pressure contact plate is reversed. That is, the present invention relates to a sheet feeding apparatus having a configuration in which a sheet feeding roller is disposed on the upper side of a cassette and the upper surface of a recording sheet in the cassette is pressed against the sheet feeding roller by a pressing plate disposed on the lower side of the cassette. Is applicable as well.

  In the above embodiment, the case where the recording apparatus using the sheet feeding apparatus is a thermal transfer recording apparatus has been described as an example. However, the present invention can be similarly applied to the case where the recording apparatus using the sheet feeding apparatus is another recording system such as an ink jet recording apparatus, a laser recording apparatus, a thermal recording apparatus, or a wire dot recording apparatus. The present invention can be widely applied regardless of the form of the recording head, such as a serial type or a line type. Furthermore, the present invention can be applied regardless of the number and arrangement of recording heads.

It is a side view of one embodiment of a sheet feeding device according to the present invention. FIG. 2 is a perspective view of the sheet feeding device in FIG. 1. FIG. 2 is a side view showing a state of transmission of elastic force acting on the pressure contact means from the elastic means in the sheet feeding apparatus of FIG. 1. FIG. 3 is a perspective view showing a state of transmission of elastic force acting on the pressure contact means from the elastic means in the sheet feeding apparatus of FIG. 1. 1 is a longitudinal sectional view showing an embodiment of a recording apparatus suitable for using a sheet feeding apparatus according to the present invention. It is a longitudinal cross-sectional view of a conventional sheet feeding apparatus. FIG. 7 is a perspective view of the sheet feeding device in FIG. 6.

Explanation of symbols

1 Sheet storage means (cassette)
2 Feeding means (paper feed roller)
3 Pressure welding means (pressure welding plate)
4 First lever member 4a Shaft 4b One lever portion (first lever member)
4c The other lever part (first lever member)
4d Energized portion 4f Tip portion 5 Second lever member 5a Shaft 5b One lever portion (second lever member)
5c Pressing part 5d The other lever part (second lever member)
5e Affected part 6 Elastic means (spring)
7 Engagement section 11 Recording sheet (recording medium)
DESCRIPTION OF SYMBOLS 21 Ink ribbon storage part of unwinding side 22 Ink ribbon storage part of winding side 23 Winding axis 24 Supply axis 25 Ink ribbon 28 Recording head (thermal head)
29 Platen (Platen roller)
DESCRIPTION OF SYMBOLS 30 Image formation part 31 Conveyance roller 50 Sheet feeding apparatus 100 Recording apparatus

Claims (6)

A sheet storage unit capable of stacking recording sheets, a feeding unit for feeding recording sheets stacked on the sheet storage unit, and a recording sheet stacked on the sheet storage unit are pressed against the feeding unit A sheet feeding device including a pressure contact means for
A first lever member rotatable about an axis parallel to the recording sheet stacked on the sheet storage means; and a first lever member rotatable about an axis parallel to the rotation center of the first lever member. 2 lever members and an elastic member extending in a direction parallel to the recording sheets stacked on the sheet storage means,
The first lever member extends in parallel with the recording sheet and can press the pressing means, and the other has a biased portion and extends in a direction intersecting the recording sheet. The lever part,
The second lever member has one lever portion acting on a biased portion of the first lever member and the other lever portion extending in a direction intersecting the recording sheet,
By causing the spring force of the elastic member to act on the other lever portion of the second lever member, the first lever member is rotated and biased via the second lever member, and the first lever member is rotated. The sheet feeding apparatus according to claim 1, wherein the pressing member is pressed by the one lever portion of the lever member so that the recording sheet is pressed against the feeding unit by the pressing member.   2. The elastic member according to claim 1, wherein one end portion of the elastic member is connected to one lever portion of the second lever member, and the other end portion is connected to an engaging portion provided in the recording apparatus. Sheet feeding device.   The sheet feeding apparatus according to claim 1, wherein the elastic member is a tension coil spring.   The sheet feeding apparatus according to claim 1, wherein the elastic member is stretched in parallel with the recording sheet along a side portion of the sheet storage unit. Sheet storage means capable of stacking recording sheets;
A feeding means for feeding the recording sheets stacked in the sheet storage means;
A pressure contact member for pressing the recording sheet loaded on the sheet storage unit rotatable about an axis parallel to the recording sheet stacked on the sheet storage unit, to the feeding unit;
A first lever member rotatable integrally with the pressure contact member about the axis;
An elastic member disposed in parallel with the recording sheet along the side of the sheet storage means;
The elastic member is urged to rotate by the elastic force of the elastic member, contacts the first lever member, and rotates by the elastic force of the elastic member in the direction in which the pressure contact member presses the recording sheet. And a second lever member for urging the sheet feeding device. A recording apparatus for recording an image on a recording sheet based on image information by a recording head, comprising the sheet feeding apparatus according to claim 1.

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