JP2008179440A - Paper feeding mechanism and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeding mechanism capable of feeding a wide paper sheet, restricting an increase in dimension of the mechanism. <P>SOLUTION: A plate push-up cam 41 for pushing up a paper feeding plate 2 toward a paper feeding roller 3 is arranged on a back surface side of a paper sheet loading surface 2a of the paper feeding plate 2. This paper feeding mechanism comprises a roller gear 6 connected to a paper feeding roller 3, a cam gear 4 connected to the plate push-up cam 41, a first driving gear 71 provided with a toothless part not engaged with a tooth part engaged with the roller gear 6 on the periphery thereof, and a second driving gear 72 engaged with the cam gear 42. The first driving gear 71 and the second driving gear 72 are integrally formed with the same shaft, and the tooth part of the first driving gear 71 is provided in a position of the periphery so as to be engaged with the roller gear 6 when the plate push-up cam 41 is moved to the position for pushing up the paper feeding plate 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a paper feeding mechanism used in an image forming apparatus such as a copying machine, a printer, a facsimile machine or the like.

An image forming apparatus such as a printer that can feed paper from the manual feed tray has a paper feed mechanism as shown in FIG. The paper feed mechanism includes a paper feed plate 92 having a paper placement surface arranged substantially on the same plane as the upper surface of the manual feed tray, and a paper feed roller 91 in contact with the paper placement surface of the paper feed plate 92. , And a roller gear 94 connected to the end of the rotation shaft of the paper feed roller 91.
Further, a cam 93 that pushes down the paper feed plate 92 from the paper placement surface side of the paper feed plate 92 and a paper feed roller 91 from the back side of the paper placement surface are provided on the side of the paper feed plate 92. A spring member 97 that is pushed up so as to come into contact with is provided.

The cam 93 and the roller gear 94 are formed coaxially and integrally. Further, the input gear 96 is disposed so as to be able to mesh with the roller gear 94.
The roller gear 94 has a missing tooth portion 94 a having no meshing teeth, and the missing tooth portion 94 a is formed at a position facing the input gear 96 when the paper feed plate 92 is pushed down by the cam 93. Yes.

When the roller gear 94 meshes with the input gear 96 and rotates, the sheet feeding roller 91 rotates and at the same time, the sheet feeding plate 92 is pushed up toward the sheet feeding roller 91 by the urging force of the spring member 97 to feed the sheet feeding plate. The sheet on the sheet 92 contacts the sheet feed roller 91, and the sheet in contact with the sheet feed roller 91 is conveyed into the image forming apparatus.
On the other hand, when the toothless portion 94a of the roller gear 94 faces the input gear 96 and the meshing between the input gear 96 and the roller gear 94 is released, the rotation of the paper feed roller 91 is stopped simultaneously with the paper feed plate. 92 is pushed down by the cam 93, the paper on the paper feed plate 92 is separated from the paper feed roller 91, and the paper supply from the paper feed plate 92 is stopped (for example, Patent Document 1).
JP-A-8-225167

However, in the configuration in which the cam 93 is arranged on the sheet placement surface side of the sheet feeding plate 92 as described above, the user's hand is not caught in the cam 93 when the user inserts his hand into the back of the manual feed tray. In addition, it was necessary to cover the cam 93 with a cover. With such a cover, the width dimension on which the sheet on the sheet feeding plate 92 can be placed becomes narrow, and a wide sheet having a width dimension substantially the same as the dimension of the sheet feeding plate 92 in the width direction (direction perpendicular to the sheet conveying direction). Could not be supplied from the manual feed tray.
Accordingly, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a paper feed mechanism capable of supplying wide paper without increasing its size.

  In order to achieve the above object, the present invention comprises a paper feed plate having a paper placement surface on which a paper is placed, and a paper feed roller disposed on the paper placement surface of the paper feed plate. In the paper mechanism, a plate push-up cam that pushes up the paper feed plate toward the paper feed roller is disposed on the back side of the paper placement surface of the paper feed plate.

According to the paper feeding mechanism of the present invention, the plate push-up cam is arranged on the back side of the paper placing surface of the paper feeding plate, so that the paper is placed on the entire width direction of the paper placing surface of the paper feeding plate. Thus, a wide sheet can be supplied from the manual feed tray without increasing the size of the sheet feeding mechanism.
In addition, by disposing the plate lifting cam on the back side of the paper loading surface of the paper feeding plate, when the paper feeding plate is displaced away from the paper feeding roller, the paper feeding plate is lowered by its own weight to feed paper. Get away from Laura. Therefore, the number of parts is reduced as compared with the case where the sheet feeding plate is sandwiched between the cam and an elastic member such as a spring, the sheet feeding plate is pushed down by the pressing force of the cam, and pushed up by the urging force of the elastic member.

  In a specific configuration, a roller gear connected to the paper feed roller, a cam gear connected to the plate push-up cam, and a toothless portion that does not mesh with a toothed portion that meshes with the roller gear on the outer periphery. And a second drive gear that meshes with the cam gear, wherein the first drive gear and the second drive gear are coaxially integrated, and the first drive gear A toothed portion is provided at a position on the outer periphery that meshes with the roller gear when the plate push-up cam moves to a position to push up the paper feed plate.

  According to the specific configuration, the structure, rotation of the paper feed roller, and displacement of the paper feed plate are compared with the case where the drive gears for rotating the roller gear and the cam gear are provided separately. The rotation control method of each drive gear for linking the two is simplified.

  In a more specific configuration, a first mark as a mark is formed on the first drive gear or a portion that rotates integrally therewith, and a portion that rotates on the plate push-up cam or integrally therewith. In addition, a second mark is formed as a mark corresponding to the first mark.

  According to the specific configuration, in the process of assembling the plate push-up cam and the first drive gear, when the plate push-up cam moves to the position where the sheet feed plate is pushed up by the first mark and the second mark. The relative position of the plate push-up cam with respect to the first drive gear can be easily and reliably arranged so that the toothed portion of the first drive gear moves to a position where it engages with the roller gear.

  In a more specific configuration, the number of teeth of the second drive gear is equal to the number of teeth of the cam gear, a third drive gear coaxially integrated with the first and second drive gears, An input gear meshing with the third drive gear can be provided.

  The present invention as an image forming apparatus includes a developing unit for forming an image to be printed on a sheet, and a conveying unit that conveys the sheet supplied to the manual feed tray toward the developing unit. Any one of the above-described paper feeding mechanisms is provided in the conveying means.

  According to the paper feed mechanism of the present invention, paper can be placed on the entire width direction of the paper placement surface of the paper feed plate, and wide paper can be supplied without increasing the size of the paper feed mechanism. It becomes.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
1 is an overall perspective view of the image forming apparatus according to the embodiment of the present invention, FIG. 2 is a plan view showing a part of the sheet feeding mechanism according to the embodiment of the present invention, and FIG. 4 is a perspective view showing a part of the paper feed mechanism, and FIG. 5 is a perspective view of a drive member of the paper feed mechanism.

  The printer apparatus shown in FIG. 1 is an example of an image forming apparatus 1 according to the present invention. In the image forming apparatus 1, a predetermined image is printed on the paper stored in the paper feed tray 11 or the paper placed on the manual feed tray 10, and the printed paper is discharged to the paper discharge tray 13. To do.

The image forming apparatus 1 has a paper feed mechanism M for conveying the paper on the manual tray 10 toward the developing means inside the manual feed tray 10.
As shown in FIG. 2, the paper feed mechanism M includes a paper feed plate 2 having a paper placement surface 2 a disposed substantially on the same plane as the paper placement surface of the manual feed tray, And a paper feed roller 3 that abuts on the paper placement surface 2a. The paper feed roller 3 includes a cylindrical main body 30 and a rotating shaft 31 that passes through the center of the main body 30. A rotation shaft 31 of the paper feed roller 3 extends in a direction orthogonal to the paper transport direction, and one end of the rotation shaft 31 is connected to a rotation center of a roller gear described later.

As shown in FIG. 3, the paper feed plate 2 is integrally formed at both ends of the paper feed plate 2 and is provided with a pair of arms 21 and 21 extending substantially perpendicularly from the paper placement surface 2a. It is swingably attached to the main body.
The hatched portion in FIG. 3 is a portion not related to the present invention.

On the back surface side of the paper placement surface 2a formed by the upper surface of the paper feed plate 2, a plate push-up cam 41 for pushing up the paper feed plate 2 toward the paper feed roller 3 provided above the paper feed plate 2; A cam gear 42 formed coaxially with the plate push-up cam 41 is disposed. The cam gear 42 is held in a rotatable state inside the image forming apparatus.
The plate push-up cam 41 is formed in a substantially semicircular shape, and as shown in FIG. 4, has an arc-shaped push-up end portion 41a away from the rotation center and a flat non-push-up end portion 41b close to the rotation center ing. Further, the pushing upper end portion 41a and the non-pushing upper end portion 41b of the plate push-up cam 41 do not have corner portions and are formed as smooth curved surfaces.

  Further, on the back surface side of the paper placement surface 2a of the paper feed plate 2, a power transmission is formed integrally with the paper feed plate 2 and protrudes from the back surface of the paper placement surface 2a and extends toward the plate push-up cam 41. A lever 20 is provided. The front end of the power transmission lever 20 is in contact with the outer peripheral surface of the plate push-up cam 41. When the plate push-up cam 41 is rotated, it comes into contact with the push-up end portion 41a or the non-push-up end portion 41a. 2 is displaced in a direction substantially orthogonal to the sheet placing surface 2 a in conjunction with the rotation of the plate push-up cam 41.

  A roller gear 6 connected to the paper feed roller 3 is disposed inside the image forming apparatus and is rotatably held in the main body of the image forming apparatus.

  On the other hand, as shown in FIG. 4, power is transmitted to the cam gear 42 and the roller gear 6 from the input gear 8 that rotates using a motor (not shown) as a power source via the drive member 7. The drive member 7 is held in a rotatable state inside the image forming apparatus, and has a first drive gear 71, a second drive gear 72, and a third drive gear 73. These drive gears 71, 72, 73 of the drive member 7 are formed coaxially and are arranged with the second drive gear 72 sandwiched between the first drive gear 71 and the third drive gear 73.

  The drive member 7 is disposed at a position where the drive gear 71 can mesh with the roller gear 6, the second drive gear 72 can mesh with the cam gear 42, and the third drive gear 73 can mesh with the input gear 8.

Each of the roller gear 6, the cam gear 42, and the input gear 8 includes a toothed portion for engaging with the drive gears 71, 72, and 73 of the drive member 7 in the entire outer periphery.
On the other hand, the second drive gear 72 has a toothed portion that meshes with the cam gear 42 in the entire outer periphery, and the number of teeth formed in the second drive gear 72 and the cam gear 42 are formed. The number of teeth is equal to each other.

The first drive gear 71 is a toothless gear having a toothed portion 71b that meshes with the roller gear 6 and a toothless portion 71c that does not mesh with the roller gear 6. The third drive gear 73 is also a toothless gear having a toothed portion 73a that meshes with the input gear 8 and a toothless portion 73b that does not mesh.
4 and 5, the portions of the gears 6, 8, 42, 71, 72, 73 where the other toothed portions illustrated are formed by hatching.

  As shown in FIG. 5, the drive member 7 further includes a locking claw 75 outside the third drive gear 73, and the locking claw 75 protrudes in a direction substantially perpendicular to the rotation axis direction of the drive member 7. Yes. Further, on the main body side of the image forming apparatus, a latch receiving portion (not shown) that can be engaged with the latching claw 75 of the drive member 7 and a rotational force are given to the drive member 7, and A spring member (not shown) is provided to be pressed and engaged with the stopper portion. The latch receiving portion moves in accordance with the energization state of a solenoid (not shown) built in the image forming apparatus.

  When the paper feed mechanism M shown in FIG. 1 described above supplies paper from the manual feed tray 10 to the main body of the image forming apparatus 1, the solenoid is energized, and the latch receiving portion and the drive member 7 shown in FIG. The engagement with the locking claw 75 is released. Then, the driving member 7 is rotated by the urging force of the spring member that has pressed the locking claw 75 of the driving member 7 against the locking receiving portion, and the third driving gear 73 of the driving member 7 shown in FIG. The tooth portion 73a moves to a position facing the input gear 8. As a result, the third drive gear 73 meshes with the input gear 8 to rotate the drive member 7.

  Due to the rotation of the drive member 7, the cam gear 42 meshing with the second drive gear 72 of the drive member 7, and the plate lifting cam 41 integrated with the cam gear 42 rotate, and from the rotation center of the plate lifting cam 41. The separated arc-shaped push-up end portion 41 a moves to a position where it comes into contact with the tip of the power transmission lever 20 extending from the sheet feeding plate 2. At the same time, the toothed portion 71b of the first drive gear 71 moves to a position facing the roller gear 6, and the first drive gear 71 and the roller gear 6 mesh with each other.

  By the movement of the power transmission lever 20, the paper feed plate 2 shown in FIG. 3 is pushed up toward the paper feed roller 3, and the paper 5 on the paper placement surface 2 a of the paper feed plate 2 is fed with the paper feed plate 2. It is sandwiched between the paper rollers 3. In synchronization with this, the paper feed roller 3 rotates. As a result, the sheet 5 in contact with the sheet feed roller 3 (the top sheet when a plurality of sheets are stacked on the manual feed tray) 5 is formed from the manual feed tray on the image formation. Supplied to the device body.

As the drive member 7 further rotates, the flat non-pushing upper end portion 41 b close to the rotation center of the plate lifting cam 41 moves to a position where it abuts against the tip of the power transmission lever 20 extending from the paper feed plate 2. At the same time, the toothless portion 71 c of the first drive gear 71 shown in FIG. 4 moves to a position facing the roller gear 6.
At this time, the rotation of the paper feed roller 3 is stopped, and at the same time, the paper feed plate 2 is lowered and the paper 5 on the paper placement surface 2 a of the paper feed plate 2 is separated from the paper feed roller 3. As a result, the supply of paper from the manual feed tray to the image forming apparatus main body is stopped.

When the driving member 7 further rotates, the toothless portion 73b of the third driving gear 73 of the driving member 7 moves to a position facing the input gear 8, and the meshing between the third driving gear 73 and the input gear 8 occurs. Canceled. In this way, the input gear 8 does not mesh with the third drive gear 73, and the power to the motor is not transmitted to the drive member 7 through the input gear 8, and the solenoid is de-energized, and FIG. The engaging claw 75 of the driving member 7 shown is engaged with the engaging receiving portion, and the rotation of the driving member 7 is stopped.
The driving member 7 rotates once every time a sheet is conveyed. When paper is repeatedly supplied from the manual feed tray 10 shown in FIG. 1 to the main body of the image forming apparatus 1, the solenoid is energized again, so that the paper feed mechanism M can manually feed the paper from the same state as described above. Paper is supplied from the tray 10 to the main body of the image forming apparatus 1.

  As described above, in order to interlock the displacement of the paper feed plate 2 and the rotation of the paper feed roller 3 shown in FIG. 3, the plate push-up cam 41 and the first drive gear 71 are connected to each other. When moving to a position where 2 is pushed up, the toothed portion 71 b of the first drive gear 71 is arranged to move to a position where it engages with the roller gear 6.

In order to arrange the first drive gear 71 and the plate push-up cam 41 as described above, the alignment protrusions as shown in FIG. 4 are provided at predetermined positions of the first drive gear 71 and the cam gear 42, respectively. (Examples of first and second marks) 71a and 42a are provided.
In the process of assembling the image forming apparatus, for example, when the cam gear 42 is attached after the drive member 7 is attached to the main body of the image forming apparatus, the alignment convex portion 42a of the cam gear 42 is moved to the first drive. The gear 71 is disposed at a predetermined position with respect to the alignment convex portion 71a (for example, on an extension of a straight line connecting the rotation center of the first drive gear 71 and the alignment convex portion 71a of the first drive gear 71).

Thus, when the toothed portion 71b of the first drive gear 71 meshes with the roller gear 6, the plate push-up cam with respect to the first drive gear 71 is pushed so that the plate push-up cam 41 pushes up the paper feed plate 2. 41 relative positions can be easily and reliably arranged.
The alignment convex portions 71a and 42a may be formed in portions that rotate integrally with the first drive gear 71 and the plate push-up cam 41, for example, the second drive gear 72 and the cam gear 42, for example. It may be formed. In addition, the positioning convex portions 71a and 42a can be changed to concave portions or color-coded coatings as long as they do not interfere with the rotation of the plate push-up cam 41 and the drive member 7.

As described above, the cam gear 42 connected to the plate push-up cam 41 is rotated by meshing with the second drive gear 72 provided on the drive member 7 by the rotation of the drive member 7 and is connected to the paper feed roller 3. The roller gear 6 rotates in mesh with the first drive gear 71 when the plate push-up cam 41 pushes the paper feed plate 2 toward the paper feed roller 3, and the paper feed plate 2 is moved from the paper feed roller 3. When leaving, it does not mesh with the first drive gear 71 and does not rotate.
In such a paper feeding mechanism, the structure and the displacement of the paper feeding plate 2 are compared with the case where the driving gears 71 and 72 for rotating the roller gear 6 and the cam gear 42 are provided separately. The method of controlling the rotation of the drive gears 71 and 72 for interlocking the rotation of the paper feed roller 3 is simplified.

  As described above, the number of teeth of the second drive gear 72 and the cam gear 42 that mesh with each other is the same, and the rotation periods of the second drive gear 72 and the cam gear 42 are the same. Further, the first drive gear 71 rotates integrally with the second drive gear 72. Therefore, when the first driving gear 71 and the plate lifting cam 41 rotate, the rotation periods of the first driving gear 71 and the plate lifting cam 41 are equal to each other, and the first driving gear 71 and the plate lifting cam 41 are Rotates as if integrated.

  As described above, by placing the plate push-up cam 41 on the back side of the paper placement surface 2a of the paper feed plate 2, the paper is placed on the entire width direction of the paper placement surface 2a of the paper feed plate 2. Accordingly, a wide sheet can be supplied from the manual feed tray 10 to the main body of the image forming apparatus 1 without increasing the size of the paper feed mechanism M of the image forming apparatus 1 shown in FIG.

  Further, by disposing the plate lifting cam 41 on the back side of the sheet placing surface 2 a of the sheet feeding plate 2, when the sheet feeding plate 2 is displaced in the direction away from the sheet feeding roller 3, the motor drives the driving member 7. When the transmission of power to is stopped, the sheet feeding plate 2 is lowered by its own weight and separated from the sheet feeding roller 3. Accordingly, the sheet feeding plate 2 is sandwiched between the plate push-up cam 41 and an elastic member such as a spring, and the sheet feeding plate 2 is pushed down by the pressing force of the cam and pushed up by the urging force of the elastic member. Thus, the number of parts is small, and the load on the motor, which is a power source for rotating the cam, is reduced.

  Further, since the pushing upper end portion 41a and the non-pushing upper end portion 41b of the plate lifting cam 41 are formed in a smooth curved surface having no corners, the sheet feeding plate 2 is smoothly displaced.

  In the above-described embodiment, the number of teeth of the second drive gear 72 and the cam gear 42 is made equal, and the rotation cycle of the first drive gear 71 and the plate push-up cam 41 is made equal. Even if the toothed portion 71b of the drive gear 71 is provided in two locations and the plate push-up cam 41 rotates twice while the first drive gear 71 rotates once, the rotation of the sheet feeding roller 3 and the sheet feeding The displacement of the plate 2 is interlocked in the same manner as described above.

  Further, in the above embodiment, the drive member 7 sandwiches the second drive gear 72 without the missing tooth portion between the first drive gear 71 having the missing tooth portion and the third drive gear 73. When the drive member 7 is molded, the extraction process from the mold is taken into consideration. Therefore, the arrangement of the drive gears 71, 72, 73 of the drive member 7 is not limited to the above arrangement.

  The present invention is applicable to printers, copiers, facsimiles, and the like.

1 is an overall perspective view of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a plan view showing a part of a paper feed mechanism according to the embodiment of the invention. The perspective view which shows a part of paper feed mechanism. The perspective view which shows a part of paper feed mechanism. The perspective view of the drive member of a paper feed mechanism. The perspective view of the conventional paper feed mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 2 ... Paper feed plate 3 ... Paper feed roller 5 ... Paper 6 ... Roller gear 7 ... Drive member 8 ... Input gear 41 ... Plate pushing-up cam 41a ... Push-up upper end part 41b ... Non-push-up upper end part 42 ... Cam gear 42a ... Alignment convex portion 71 ... First drive gear 71a ... Alignment convex portion 71b ... Toothed portion 72 ... Second drive gear 73 ... Third drive gear

Claims (6)

A paper feed plate having a paper placement surface on which paper is placed;
A paper feed roller disposed on the paper placement surface of the paper feed plate;
In a paper feed mechanism comprising
A paper feed mechanism, wherein a plate push-up cam for pushing up the paper feed plate toward the paper feed roller is disposed on the back side of the paper placement surface of the paper feed plate.   A roller gear connected to the paper feed roller, a cam gear connected to the plate push-up cam, and a first toothed portion that does not mesh with a toothed portion that meshes with the roller gear. A second drive gear that meshes with the drive gear and the cam gear; the first drive gear and the second drive gear are coaxially integrated; and the toothed portion of the first drive gear is The sheet feeding mechanism according to claim 1, wherein the sheet feeding mechanism is provided at a position on the outer periphery that meshes with the roller gear when the plate lifting cam moves to a position for pushing up the sheet feeding plate.   A first mark as a mark is formed on the first drive gear or a portion rotating integrally therewith, and the first mark is formed on the plate push-up cam or a portion rotating integrally therewith. The paper feed mechanism according to claim 2, wherein a second mark is formed as a corresponding mark.   4. The paper feed mechanism according to claim 2, wherein the number of teeth of the second drive gear is equal to the number of teeth of the cam gear. 5.   5. The sheet feeding mechanism according to claim 2, further comprising: a third driving gear coaxially integrated with the first and second driving gears; and an input gear meshing with the third driving gear. Developing means for forming an image for printing on paper;
Conveying means for conveying the paper supplied to the manual tray toward the developing means;
In an image forming apparatus comprising:
An image forming apparatus comprising: the paper feeding mechanism according to claim 1 in the transport unit.

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