JP2012062188A - Paper feeding cassette, image forming apparatus, and method of opening and closing paper feeding cassette - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeding cassette having an easy-open paper feed cover, and to provide an image forming apparatus, and a method of opening the paper feeding cassette.SOLUTION: The paper feeding cassette includes: a paper feed cover 20 to be opened and closed to house roll paper P; a pressing arm 30 with one end rotatably supported and the other end biased to press the roll paper to a paper feed roller 2; a return spring 40 with one end connected to the pressing arm and the other end movably supported between a first position and a second position where a larger biasing force is generated than in the first position; and an auxiliary arm 50 that moves one end of the return spring to the second position when closing the paper feed cover and moves the other end of the return spring to the first position when opening the paper feed cover.

Description

  The present invention relates to a sheet feeding cassette, an image forming apparatus, and a method for opening and closing the sheet feeding cassette.

  2. Description of the Related Art Conventionally, printers that use roll paper in which a long recording paper is wound around a core are known. The printer unwinds the recording paper from the roll paper by the paper feed roller and prints on the unwound recording paper. For this reason, the roll paper is pressed against the paper feed roller at the time of printing, and the roll paper is released at the time of replacement of the roll paper in order to facilitate replacement work.

  Patent Document 1 below discloses a paper feed cassette having a support member that presses roll paper against a paper feed roller. The support member urges the roll paper to the paper feed roller by a spring force and rotates according to the opening and closing of the paper feed lid. When the paper supply lid is opened, the support member rotates in a direction to release the pressing of the roll paper against a force for urging the roll paper. Thereby, the pressing of the roll paper is released when the paper supply lid is opened, and the roll paper can be easily replaced.

JP 2007-161456 A

  By the way, in recent years, as the print size increases and the number of continuous prints increases, the width and roll diameter of the roll paper increase, and the roll paper tends to increase in weight. Here, in the paper feeding cassette, by balancing the weight of the roll paper and the spring force, the pressure contact of the roll paper against the paper feed roller becomes substantially constant regardless of the winding diameter. However, as the roll paper becomes heavier, the spring force must be increased. Then, when opening the paper feed lid, a large force is required to rotate the support member in the direction to release the pressing of the roll paper, which makes it difficult to open the paper feed lid.

  Therefore, the present invention is intended to provide a paper feed cassette, an image forming apparatus, and a method for opening and closing the paper feed cassette that can easily open a paper feed lid.

  According to an aspect of the present invention, a paper feed lid that is opened and closed to store roll paper, one end is rotatably supported, and the other end is capable of supporting the roll paper shaft. A pressing arm biased to press against the paper roller, one end connected to the pressing arm, the other end of the first position, and a second position generating a biasing force larger than the first position. And the other end of the urging member is moved to the second position when the paper feed lid is closed, and the other end of the urging member is moved to the second position when the paper feed lid is opened. A paper feed cassette is provided that includes an auxiliary arm that is moved to a position of 1.

  The pressing arm may press the roll paper against the paper feed roller by an urging force generated in the urging member in a state where the other end of the urging member is moved to the second position.

  The biasing member is set so that the amount of movement between the first position and the second position is smaller than the amount of movement that occurs when the paper feed lid is changed from the closed state to the fully opened state. Also good.

  The auxiliary arm is pressed by the paper feed lid to move the other end of the biasing member to the second position, and the pressure by the paper feed lid is released to move the other end of the biasing member to the first position. Also good.

  The pressing arm supports the roll paper shaft so that the roll paper is pressed against the paper supply roller when the paper supply lid is closed, and releases the support of the roll paper shaft when the paper supply lid is opened. The roll paper may be moved to a replaceable position.

  The urging member may be a torsion spring having a rotation fulcrum shaft of the pressing arm as a torsion center axis.

  According to another aspect of the present invention, there is provided an image forming apparatus including a paper feed roller and a paper feed cassette, wherein the paper feed cassette includes a paper feed lid that is opened and closed to store roll paper; One end is rotatably supported, the other end is capable of supporting the roll paper shaft, the pressing arm is urged to press the roll paper against the paper feed roller, and one end is connected to the pressing arm. An urging member whose end is movably supported between a first position and a second position that generates a larger urging force than the first position; and An auxiliary arm that moves the other end to the second position and moves the other end of the biasing member to the first position when the paper supply lid is opened, and supports the other end of the biasing member to be movable An image forming apparatus further including a movable support portion is provided.

  According to another aspect of the present invention, a paper feed lid that is opened and closed to store roll paper, one end is rotatably supported, and the other end is capable of supporting the roll paper shaft. A pressing arm urged to press the paper against the paper feed roller, one end connected to the pressing arm, the other end is a first position, and a second position generates a larger urging force than the first position. A method of opening and closing a paper feed cassette having a biasing member supported so as to be movable between positions and an auxiliary arm for moving the other end of the biasing member, wherein the auxiliary arm is closed when the paper feed lid is closed The other end of the urging member is moved to the second position via the auxiliary member, and the other end of the urging member is moved to the first position via the auxiliary arm when the paper supply lid is opened. An opening and closing method is provided.

  As described above, according to the present invention, it is possible to provide a paper feeding cassette, an image forming apparatus, and a method for opening and closing a paper feeding cassette that can easily open a paper feeding lid.

It is a perspective view which shows the external appearance of the back side of the paper feed cassette which can apply this invention. FIG. 6 is a perspective view showing an appearance of the front side of the paper feed cassette (a state where a paper feed lid is closed). FIG. 6 is a perspective view illustrating an appearance of the front side of the paper feed cassette (a state where a paper feed lid is opened). FIG. 2 is a schematic diagram illustrating an internal state of a printer in which a paper feed cassette is mounted. It is a sectional side view which shows the paper feed cassette (state which opened the paper feed lid) without an auxiliary arm. FIG. 6 is a side cross-sectional view showing a paper feed cassette without an auxiliary arm (a state where a paper feed lid is closed) (a state at the start of using roll paper). FIG. 5 is a side sectional view showing a paper feed cassette without an auxiliary arm (a state where a paper feed lid is closed) (a state after starting use of roll paper). It is a figure which shows the force which acts on a torsion spring. It is a sectional side view which shows the paper feed cassette (state which opened the paper feed lid) with an auxiliary arm. It is a sectional side view which shows the paper feed cassette (state which closed the paper feed lid) with an auxiliary arm. It is a figure which shows the force which acts on a torsion spring at the time of opening and closing of a paper supply lid | cover in the case where an auxiliary arm is not accompanied. It is a figure which shows the force which acts on a torsion spring at the time of opening and closing of a paper supply lid | cover in the case of accompanying an auxiliary arm.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

[1. Peripheral configuration of paper cassette 1]
First, the peripheral configuration of the paper feed cassette 1 will be described with reference to FIGS.

  FIG. 1 shows the appearance of the back side of a paper feed cassette 1 to which the present invention can be applied. The paper feed cassette 1 has a cassette body 10 and a paper feed lid 20 attached to the front surface of the cassette body 10. The cassette body 10 is formed with an opening 11 for pressing the roll paper P accommodated in the paper feed cassette 1 against the paper feed roller 2. That is, when the paper feed cassette 1 containing the roll paper P is mounted on a printer main body (not shown), the paper feed roller 2 provided on the printer main body is pressed against the outer peripheral surface of the roll paper P through the opening 11. A paper feed port 12 for unwinding the roll paper P to the outside of the paper feed cassette 1 is formed below the opening 11.

  2 and 3 show the paper feed cassette 1 with the paper feed lid 20 closed and the paper feed lid 20 opened. The paper supply lid 20 is configured to be rotatable about the support shaft 61 by the connecting arm 60. When the paper supply lid 20 is rotated upward, the paper supply lid 20 is closed. That is, the paper feed cassette 1 can be mounted on the printer body by opening the paper feed lid 20 and storing the roll paper P in the cassette body 10 (main body chassis 10 ') and then closing the paper feed lid 20. A rotating roller 13 is attached to the inside of the paper feed lid 20 so that the inner surface of the paper feed lid 20 does not contact the outer peripheral surface of the roll paper P with the paper feed lid 20 closed.

  FIG. 4 shows the internal state of the printer in which the paper feed cassette 1 is mounted. The roll paper P is stored in the paper feed cassette 1 mounted on the printer, and is unwound from the paper feed port 12 by the rotational drive of the paper feed roller 2. The roll paper P that has passed through the paper supply port 12 is disposed between the thermal head 3 and the platen roller 4, and is conveyed by the grip roller 5 and the pinch roller 6.

  Further, the ink ribbon R is engaged with a take-up spool engaging portion 7 and a supply spool engaging portion 8 that are rotatably provided in the printer main body, and passes between the thermal head 3 and the platen roller 4. Are arranged as follows. The ink ribbon R is drawn from the supply spool by the take-up spool engaging portion 7 that rotates according to the image data to be printed, passes between the thermal head 3 and the platen roller 4, and takes up the take-up spool. It is wound up on the winding spool engaged with the engaging portion 7 for use.

  In the thermal head 3, a plurality of heating elements (not shown) are arranged in a line shape in the width direction of the roll paper P. The thermal head 3 is positioned slightly away from the platen roller 4 when not printing, but presses the platen roller 4 at the start of printing, and the ink ribbon R between the heating element arrangement portion and the platen roller 4 is pressed. And roll paper P. That is, the heating element of the thermal head 3 presses the roll paper P via the ink ribbon R on the platen roller 4.

  When the image data is input, the roll paper P is sequentially conveyed by the rotational drive of the grip roller 5. Further, the ink ribbon R is sequentially wound at the same speed as the roll paper P by the rotational drive of the winding spool engaging portion 7. At the same time, the heating elements on the thermal head 3 are selectively energized and driven by the drive control signal, and thermal energy is supplied from the heating elements to the ink ribbon R. Then, the ink applied to the ink ribbon R is transferred to the roll paper P in accordance with the amount of heat generated by the heating element, and printing is performed. Then, the printed roll paper P is cut at a printing portion by a cutter (not shown) and discharged from a paper discharge port (not shown).

[2. Paper cassette 1 without auxiliary arm 50]
Next, the configuration and operation of the paper feed cassette 1 without the auxiliary arm 50 will be described with reference to FIGS. 5 to 8 show a state where the cover member is removed from the cassette body 10.

  FIG. 5 shows the paper feed cassette 1 with the paper feed lid 20 open. 6 and 7 show the paper feed cassette 1 with the paper feed lid 20 closed. The roll paper P is in a state at the start of use (unconsumed state) in FIG. 6, and in a state after the start of use (consumed state) in FIG.

  The paper feed cassette 1 has a main body chassis 10 ′ of the cassette main body 10 and a paper feed lid 20. In the paper feed cassette 1, a pressing arm 30, a torsion spring 40 (biasing member), and a connecting arm are provided. 60 and first and second locking mechanisms 70 and 75 are provided.

  The roll paper P is configured by winding a long recording paper around a winding core (not shown), and a paper holder 81 is inserted into the winding core. The paper holder 81 is provided with a paper shaft 82 that is inserted into the V-shaped groove 14 of the main body chassis 10 ′.

  One end of the paper supply lid 20 is rotatably supported by the fulcrum shaft 15 of the main body chassis 10 ′. At the other end of the paper supply lid 20, an engagement protrusion 21 that engages with the engagement groove 76 of the second lock mechanism 75 is provided. In addition, a surface 22 that is pressed by a pressing surface 51 of an auxiliary arm 50 to be described later is provided in the center of the paper supply lid 20 in a state where the paper supply lid 20 is closed.

  One end of the pressing arm 30 is rotatably supported by the rotation fulcrum shaft 16 of the main body chassis 10 ′. A pressing surface 31 that moves the paper shaft 82 along the V-shaped groove 14 is formed on the upper surface of the other end of the pressing arm 30. A guide protrusion 32 that moves in the guide groove 62 of the connecting arm 60 is provided on the side surface of the other end of the pressing arm 30.

  The center of the torsion spring 40 is supported by the rotation fulcrum shaft 16 together with the pressing arm 30, and one end is connected to the pressing arm 30. Here, in the paper feed cassette 1 without the auxiliary arm 50, the other end 41 of the torsion spring 40 is supported by a fixed support member 91 fixed to the printer main body. A restoring force Fr acts on the torsion spring 40 so as to rotate the pressing arm 30 upward.

  One end of the connecting arm 60 is rotatably supported by the fulcrum shaft 61 of the paper supply lid 20. The connecting arm 60 is provided with a guide groove 62 that engages with the guide protrusion 32 of the pressing arm 30 in the longitudinal direction.

  The first lock mechanism 70 restricts the rotation of the pressing arm 30 so that the sheet feeding lid 20 does not pivot upward due to the restoring force Fr of the torsion spring 40 in a state where the sheet feeding lid 20 is open. The first locking mechanism 70 fixes the pressing arm 30 to the main body chassis 10 ′ in a state where the paper supply lid 20 is fully opened, and the paper supply lid 20 is closed (the paper supply lid 20 is slightly held). The pressing arm 30 is released in a state in which the lifting force is applied. The first lock mechanism 70 is provided with a spring 71 in order to keep the pressing arm 30 fixed.

  The second lock mechanism 75 regulates the rotation of the paper feed lid 20 so that the paper feed lid 20 does not rotate downward with the paper feed lid 20 closed. The second lock mechanism 75 is provided with an engagement groove 76 that engages with the engagement protrusion 21 of the paper supply lid 20. The second lock mechanism 75 is provided with a paper feed lid in order to prevent rattling between the paper feed lid 20 and the main body chassis 10 'during movement or printing with the paper feed lid 20 closed. A spring (not shown) is provided that urges 20 downward to strengthen the engagement between the engagement protrusion 21 and the engagement groove 76.

  When closing the paper supply lid 20 from the state shown in FIG. 5, the user slightly lifts the paper supply lid 20 around the fulcrum shaft 15. Then, the fixing of the pressing arm 30 by the first lock mechanism 70 is released, and the pressing arm 30 is rotated upward by the restoring force Fr of the torsion spring 40. When the pressing arm 30 rotates, the paper shaft 82 is pushed up along the V-shaped groove 14 by the pressing surface 31 of the pressing arm 30, and the roll paper P is pressed against the paper supply roller 2. When the user further lifts the paper feed lid 20 around the fulcrum shaft 15, the paper feed lid 20 is rotated upward and closed while the connection arm 60 is rotated. When the paper supply lid 20 is completely closed, the downward rotation of the paper supply lid 20 is restricted by the second lock mechanism 75 through the engagement of the engagement protrusion 21 and the engagement groove 76.

FIG. 8 shows the force acting on the torsion spring 40. As shown in FIG. 8, in a state where the paper supply lid 20 is closed, the restoring force Fr of the torsion spring 40 acts on the roll paper P together with its own weight W of the roll paper P. The roll paper P is pressed against the paper feed roller 2 by a force Fp corresponding to the difference between the weight W of the roll paper P and the restoring force Fr of the torsion spring 40. Here, the restoring force Fr of the torsion spring 40 is generated by generating a torsion angle θ ₀ with respect to the free angle of the spring 40.

  Here, a greater restoring force Fr acts on the torsion spring 40 as the weight of the roll paper P increases, and a smaller restoring force Fr acts on the torsion spring 40 as the weight of the roll paper P decreases. Then, the pressing arm 30 moves the roll paper P toward the paper feed roller 2 in accordance with the consumption of the roll paper P. Therefore, the pressure contact force between the paper feed roller 2 and the roll paper P is always constant due to the balance between the own weight W of the roll paper P and the restoring force Fr of the torsion spring 40, and the torque of the paper feed roller 2 is stabilized. Can do.

  On the other hand, when opening the paper feed lid 20 from the state shown in FIG. 6 or FIG. 7, the user presses the paper feed lid 20 against the main body chassis 10 ′ side. Then, in the second lock mechanism 75, the engagement protrusion 21 and the engagement groove 76 (see FIG. 5) are disengaged against the spring force, and the fixing of the paper feed lid 20 is released. When the user lowers the paper supply lid 20 around the fulcrum shaft 15, the connecting arm 60 rotates, and the paper supply lid 20 rotates downward and opens to some extent. Here, according to the rotation of the connecting arm 60, the guide groove 62 of the connecting arm 60 moves until it is locked to the guide protrusion 32 of the pressing arm 30.

  When the user further lowers the paper feed lid 20, the pressing arm 30 rotates downward about the rotation fulcrum shaft 16 against the restoring force Fr of the torsion spring 40 through the engagement of the guide protrusion 32 and the guide groove 62. Move. Further, the pressing of the roll paper P is released by the rotation of the pressing arm 30, and the paper shaft 82 is lowered along the V-shaped groove 14 to the bent portion (V-shaped apex) by its own weight W. When the paper supply lid 20 is completely opened, the upward rotation of the paper supply lid 20 is restricted by the first lock mechanism 70. Thereby, the roll paper P can be easily taken out from the paper feed cassette 1.

When the paper supply lid 20 is completely opened, the user needs to rotate the pressing arm 30 downward against the restoring force Fr of the torsion spring 40. Here, it is assumed that _a torsion angle Δθ _a is further generated in the torsion spring 40 from the closed state to the fully opened state. In this case, the user needs to apply a force of maximum Fo = k (θ ₀ + Δθ _a ) to the torsion spring 40 in order to completely open the paper feed lid 20. When the roll paper P becomes heavier, the twist angle θ ₀ increases, and the user needs to apply a large force to the torsion spring 40.

[3. Paper cassette 1 with auxiliary arm 50]
Next, the configuration and operation of the paper feed cassette 1 with the auxiliary arm 50 will be described with reference to FIGS.

  9 and 10 show a paper feed cassette 1 with an auxiliary arm 50 according to an embodiment of the present invention. 9 and 10 respectively show the sheet cassette 1 with the sheet supply lid 20 open and closed. 9 and 10 also show a state in which the cover member has been removed from the cassette body 10.

  In the sheet feeding cassette 1, an auxiliary arm 50 is provided in addition to the pressing arm 30, the torsion spring 40, the connecting arm 60, and the first and second lock mechanisms 70 and 75. The printer main body is provided with a guide 93 for guiding the horizontal movement of the auxiliary arm 50. The paper feed cassette 1 stores roll paper P that has been increased in weight by increasing the width and the winding diameter.

  Here, in the paper feed cassette 1 shown in FIGS. 9 and 10, the other end 41 of the torsion spring 40 is supported by a movable support member 92 movably supported by the printer body. The other end 41 of the torsion spring 40 moves about the rotation fulcrum shaft 16 as the movable support member 92 engages with the guide groove 94 of the guide 93 and moves.

  The auxiliary arm 50 is a substantially L-shaped member that can move horizontally with respect to the main body chassis 10 '. The auxiliary arm 50 is supported by the main body chassis 10 ′ via a guide groove 53 that guides the horizontal movement of the auxiliary arm 50. The auxiliary arm 50 has a pressing surface 51 that presses the paper supply lid 20 at one end, and a pressing surface 52 (see FIG. 10) that presses the movable support member 92 at the other end.

  When closing the paper feed lid 20 from the state shown in FIG. 9, the user slightly lifts the paper feed lid 20 around the fulcrum shaft 15. Then, the fixing of the pressing arm 30 by the first lock mechanism 70 is released, and the pressing arm 30 is rotated upward by the restoring force Fr of the torsion spring 40. Then, the user rotates the paper supply lid 20 upward until the surface 22 of the paper supply lid 20 contacts the pressing surface 51 of the auxiliary arm 50.

The user further rotates the paper supply lid 20 in contact with the auxiliary arm 50 upward. Then, the auxiliary arm 50 moves to the back side (the right side in FIG. 9) of the paper feed cassette 1 by the rotation of the paper feed lid 20 and presses the movable support member 92 to the back side through the pressing surface 52. By the pressing of the movable support member 92, the other end 41 of the torsion spring 40 supported by the movable support member 92 moves to the back side, and the torsion spring 40 has a torsion angle Δθ _b corresponding to the amount of movement of the other end 41. Will occur. Here, upward rotational force acts on the pressing arm 30 by the generation of the twist angle Δθ _b .

On the other hand, the roll paper P is pressed against the paper feed roller 2 by the paper shaft 82 being pushed up along the V-shaped groove 14 by the pressing surface 31 of the pressing arm 30. When the paper supply lid 20 is completely closed, the downward rotation of the paper supply lid 20 is restricted by the second lock mechanism 75 through the engagement of the engagement protrusion 21 and the engagement groove 76. Thereby, the pressing force by the pressing arm 30 can be enhanced by the twist angle Δθ _b generated in the torsion spring 40.

Here, in the completely closed the paper feed cover 20, a force to press the sheet feed cover 20 to the main body chassis 10 'is acting by a force corresponding to the torsional angle [Delta] [theta] _b. Therefore, in the second lock mechanism 75, the engagement between the engagement protrusion 21 and the engagement groove 76 can be strengthened without providing a spring.

In the state where the paper supply lid 20 is closed, the restoring force Fr of the torsion spring 40 acts on the roll paper P together with the weight W of the roll paper P. The roll paper P is pressed against the paper feed roller 2 by a force Fp corresponding to the difference between the weight W of the roll paper P and the restoring force Fr of the torsion spring 40. Here, the restoring force Fr of the torsion spring 40 is generated by generating torsion angles θ ₀ and Δθ _b with respect to the free angle of the spring 40.

The torsion angle component Δθ _b is generated by the movement of the other end 41 of the torsion spring 40 due to the action of the auxiliary arm 50. The self-weight W of the roll paper P and the restoring force Fr of the torsion spring 40 are balanced by the restoring force Fr corresponding to the twist angles θ ₀ and Δθ _b . In this case, the user needs to apply a force of maximum Fc ′ = k (θ ₀ + Δθ _b ) to the torsion spring 40 in order to completely close the paper supply lid 20.

On the other hand, when opening the paper supply lid 20 from the state shown in FIG. 10, the user presses the paper supply lid 20 against the main body chassis 10 'side. Then, in the second lock mechanism 75, the engagement protrusion 21 and the engagement groove 76 (see FIG. 9) are disengaged against the spring force, and the fixing of the paper feed lid 20 is released. Then, the auxiliary arm 50 moves to the front side (left side in FIG. 10) of the paper feed cassette 1 by the restoring force Fr of the torsion spring 40, and the paper feed lid 20 rotates downward by the pressing of the auxiliary arm 50. Thus, the torsion spring 40, a portion corresponding to a torsion angle [Delta] [theta] _b of the restoring force Fr is released.

  When the user rotates the paper supply lid 20 further downward, the connecting arm 60 is rotated, and the paper supply lid 20 is rotated downward to be further opened. Here, according to the rotation of the connecting arm 60, the guide groove 62 of the connecting arm 60 moves until it is locked to the guide protrusion 32 of the pressing arm 30. When the user further lowers the paper feed lid 20, the pressing arm 30 rotates downward about the rotation fulcrum shaft 16 against the restoring force Fr of the torsion spring 40 through the engagement of the guide protrusion 32 and the guide groove 62. Move.

  Further, the pressing of the roll paper P is released by the rotation of the pressing arm 30, and the paper shaft 82 descends along the V-shaped groove 14 to the bent portion with its own weight W. When the paper supply lid 20 is completely opened, the upward rotation of the paper supply lid 20 is restricted by the first lock mechanism 70. Thereby, the roll paper P can be easily taken out from the paper feed cassette 1.

When the paper supply lid 20 is completely opened, the user needs to rotate the pressing arm 30 downward against the restoring force Fr of the torsion spring 40. Here, it is assumed that _a torsion angle Δθ _a is further generated in the torsion spring 40 from the closed state to the fully opened state. In this case, since the urging force corresponding to the twist angle Δθ _b is released when the auxiliary arm 50 is moved, the maximum Fo ′ = k (θ ₀ + Δθ _a ) is required for the user to fully open the paper supply lid 20. Must be applied to the torsion spring 40.

[4. Force acting on torsion spring 40]
FIG. 11 shows the force acting on the torsion spring 40 when the paper supply lid 20 is opened and closed without the auxiliary arm 50. As shown in FIG. 11, when the auxiliary arm 50 is not attached, the other end 41 of the torsion spring 40 is supported by the fixed support member 91.

When the paper supply lid 20 is closed, as shown in FIG. 8, the torsion spring 40 has a torsion angle θ ₀ with respect to the natural angle of the spring. The torsion spring 40 appropriately presses the roll paper P against the paper feed roller 2 with a restoring force Fr corresponding to the twist angle θ ₀ .

When closing the paper supply lid 20 (state 1 in FIG. 11), the torsion spring 40 transitions from the state of the twist angle θ ₀ + Δθ _{a to} the state of the twist angle θ ₀ . Here, in the torsion spring 40, a transition from the state of the twist angle θ ₀ + Δθ _{a to} the state of the twist angle θ ₀ occurs due to the restoring force Fr. Therefore, the user does not need force to close the paper supply lid 20 (Fc = 0).

Further, (Condition 2 in FIG. 11) when opening the feed lid 20, the torsion spring 40, a transition to a state of twist angle θ _{0 +} Δθ _a from the state of the twist angle theta _0. Therefore, the user needs a force of maximum Fo = k (θ ₀ + Δθ _a ) to open the paper supply lid 20.

  FIG. 12 shows the force acting on the torsion spring 40 when the paper feed lid 20 is opened and closed when the auxiliary arm 50 is involved. As shown in FIG. 12, when the auxiliary arm 50 is attached, the other end 41 of the torsion spring 40 is supported by the movable support member 92.

When the paper supply lid 20 is closed, the torsion spring 40 has a torsion angle θ ₀ + Δθ _b with respect to the natural angle of the spring. The torsion angle component Δθ _b is generated by moving the other end 41 of the torsion spring 40 by the action of the auxiliary arm 50 in order to increase the restoring force Fr of the torsion spring 40. The torsion spring 40 appropriately presses the roll paper P weighted by the restoring force Fr corresponding to the twist angle θ ₀ + Δθ _b to the paper feed roller 2.

When the paper supply lid 20 is closed (state 1 in FIG. 12), the torsion spring 40 transitions from the state of the twist angle θ ₀ + Δθ _{a to} the state of the twist angle θ ₀ + Δθ _b . Here, the torsion spring 40, after shifting to the state of the twist angle theta ₀ from the state of twist angle θ _{0 +} Δθ _a by the restoring force Fr, a transition to a state of twist angle θ _{0 +} Δθ _b by the action of the auxiliary arm 50. In this state, the other end 41 of the torsion spring 40 is moved to the second position. Therefore, the user needs a maximum force Fc ′ = k (θ ₀ + Δθ _b ) to close the paper supply lid 20.

Also, if you open the paper feed cover 20 (state 2 in FIG. 12), the torsion spring 40, a transition to a state of twist angle θ ₀ + Δθ _a from the state of the twist angle θ ₀ + Δθ _b. Here, the torsion spring 40, a transition from the state of twist angle θ _{0 +} Δθ _b by the restoring force Fr to the torsional angle theta ₀ state. In this state, the other end 41 of the torsion spring 40 is moved to the first position. Furthermore, the torsion spring 40 transitions to _a state of _a torsion angle θ ₀ + Δθ _a . Therefore, in order to open the paper supply lid 20, the user requires a maximum force Fo ′ = k (θ ₀ + Δθ _a ).

  That is, when the roll paper P is increased in weight, if the auxiliary arm 50 is not attached, the user needs to apply an extra force corresponding to the weight increment of the roll paper P when opening the paper supply lid 20. However, when the auxiliary arm 50 is attached, the force applied when the paper feed lid 20 is opened can be dispersed and acted when the paper feed lid 20 is opened and closed by the action of the auxiliary arm 50. Therefore, the user can reduce the force to be applied excessively when the paper supply lid 20 is opened by applying the force in a distributed manner.

Furthermore, the user attaches the auxiliary arm 50 and sets the spring constant appropriately, so that the user needs to open and close the paper supply lid 20 rather than the case where the auxiliary arm 50 is not attached, despite the weight of the roll paper P being increased. The force can be reduced. For this reason, the spring constant is set so that the torsion angle component Δθ _b is less than Δθ _a . Then, the maximum force Fc ′ for closing the paper supply lid 20 using the auxiliary arm 50 is the maximum force Fo for opening the paper supply lid 20 without using the auxiliary arm 50 or the paper supply lid using the auxiliary arm 50. It becomes smaller than the maximum force Fo ′ for opening 20. Therefore, despite the weight of the roll paper P, the force required to open and close the paper supply lid 20 is reduced.

[5. Summary]
As described above, according to the paper feed cassette 1 according to the embodiment of the present invention, the urging force that presses the roll paper P against the paper feed roller 2 is increased by the force that closes the paper feed lid 20. By releasing when opening 20, the paper supply lid 20 can be easily opened.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

  For example, in the above description, the case where the torsion spring 40 is used as the biasing member has been described. However, as the urging member, a spring member such as a coil spring or a leaf spring, or another elastic member may be used.

DESCRIPTION OF SYMBOLS 1 Paper feed cassette 2 Paper feed roller 10 Cassette main body 10 'Main body chassis 20 Paper feed cover 30 Pressing arm 40 Torsion spring (biasing member)
50 Auxiliary arm 60 Connecting arm 70 First lock mechanism 75 Second lock mechanism P Roll paper

Claims (8)

A paper supply lid that is opened and closed to store roll paper;
One end is rotatably supported, the other end is capable of supporting the roll paper shaft, and a pressing arm biased to press the roll paper against a paper feed roller;
An urging member having one end coupled to the pressing arm and the other end movably supported between a first position and a second position generating a larger urging force than the first position;
Auxiliary for moving the other end of the biasing member to the second position when the paper feed lid is closed and moving the other end of the biasing member to the first position when the paper feed lid is opened. A paper cassette with an arm.   The pressing arm presses the roll paper against the paper feed roller by a biasing force generated in the biasing member in a state where the other end of the biasing member is moved to the second position. The paper cassette described in 1.   The biasing member is configured such that the amount of movement between the first position and the second position is smaller than the amount of movement that occurs when the paper supply lid is changed from a closed state to a fully opened state. The paper feed cassette according to claim 1, wherein   The auxiliary arm is pressed by the paper feed lid to move the other end of the urging member to the second position, and the pressure by the paper feed lid is released and the other end of the urging member is moved to the first position. The sheet feeding cassette according to claim 1, wherein the sheet feeding cassette is moved to a position of 1.   The pressing arm supports the roll paper shaft so as to press the roll paper against the paper supply roller when the paper supply lid is closed, and the roll paper when the paper supply lid is opened. The paper feed cassette according to claim 1, wherein the support of the shaft is released and the roll paper is moved to a replaceable position.   The sheet feeding cassette according to claim 1, wherein the urging member is a torsion spring having a rotation fulcrum shaft of the pressing arm as a torsion center axis. An image forming apparatus including a paper feed roller and a paper feed cassette,
The paper cassette is
A paper supply lid that is opened and closed to store roll paper;
One end is rotatably supported, the other end is capable of supporting the roll paper shaft, and a pressing arm biased to press the roll paper against the paper feed roller;
An urging member having one end coupled to the pressing arm and the other end movably supported between a first position and a second position generating a larger urging force than the first position;
Auxiliary for moving the other end of the biasing member to the second position when the paper feed lid is closed and moving the other end of the biasing member to the first position when the paper feed lid is opened. Arm and
An image forming apparatus further comprising a movable support portion that movably supports the other end of the urging member. A paper feed lid that is opened and closed to store roll paper, one end is rotatably supported, the other end can support the roll paper shaft, and presses the roll paper against the paper feed roller The biased pressing arm, one end is connected to the pressing arm, and the other end is movable between a first position and a second position that generates a biasing force larger than the first position. A method of opening and closing a paper feed cassette having a supported biasing member and an auxiliary arm that moves the other end of the biasing member,
Moving the other end of the biasing member to the second position via the auxiliary arm when the paper supply lid is closed;
A method of opening and closing a paper feed cassette, comprising: moving the other end of the biasing member to the first position via the auxiliary arm when the paper feed lid is opened.

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