JP2013116799A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve reduction in the size of an image forming device by reducing the thickness of a holding member, in the image forming device rotating a roller feeding a recording sheet placed on a tray by transmitting a drive force from the other end side of a holding member rotatably holding the roller at one end side.SOLUTION: When a sun gear 81 is rotated in a counterclockwise direction, a planetary gear 82 is also swingingly moved in the same direction, and meshed with an input gear 89 rotatably mounted to a support shaft 28 of a sheet supply arm 26 (A). The rotation of the input gear 89 is transmitted to a sheet supply roller 25 through a toothed pulley 91, a toothed belt 93, and a toothed pulley 92. Since the mechanism transmitting drive force from a base end side of the sheet supply arm 26 to a tip side for driving the sheet supply roller 25 is constituted by using the toothed belt 93 installed between the toothed pulleys 91, 92, thicknesses of the mechanism and the sheet supply arm 26 are reduced in the thickness direction.

Description

  The present invention relates to an image forming apparatus including an image forming unit that forms an image on a recording sheet. More specifically, the image forming unit is configured such that a recording sheet placed on a tray is held by a roller held on one end side of a holding member. The present invention relates to an image forming apparatus that sends the image to

  Conventionally, in an image forming apparatus such as an ink jet printer, a recording sheet such as a recording sheet placed on a tray is sent toward the image forming unit by a roller held at one end of a holding member such as a swing arm. Has been proposed. In that case, it has been proposed that the driving force is transmitted from the other end of the holding member to the roller held at the one end by a gear train provided on the holding member (see, for example, Patent Document 1).

JP 2009-249134 A

  However, when the driving force is transmitted by a gear train provided on the holding member, the thickness of the holding member (the length in the direction perpendicular to the direction from the one end to the other end and perpendicular to the rotation axis of the roller) Is defined by the size of the gears constituting the gear train. For this reason, the holding member cannot be thinned well in the thickness direction, which is an obstacle to downsizing the image forming apparatus. However, it is possible to reduce the thickness of the holding member by arranging a large number of small-diameter gears, but in that case, not only will the number of parts increase and the manufacturing cost will increase, but the noise generated between the gears will overlap, resulting in large noise. There is a problem of becoming, it is not realistic.

  Accordingly, the present invention provides an image forming apparatus in which a roller for feeding a recording sheet placed on a tray is rotated by transmitting a driving force from the other end side of a holding member that rotatably holds the roller to one end side. An object of the present invention is to reduce the size of the image forming apparatus by reducing the thickness of the holding member.

  The image forming apparatus of the present invention made to achieve the above object includes a tray on which a recording sheet is placed, an image forming unit that forms an image on the recording sheet, and a rotational drive that is placed on the tray. A roller for feeding the placed recording sheet toward the image forming unit, and a holding member that rotatably supports the roller at one end side and is supported by a support member provided at the other end side above the tray A driving shaft that transmits a driving force from a motor, a belt that is provided on the holding member and extends along a direction from the other end to the one end, and a driving force from the driving shaft to the belt. A first transmission unit that transmits the second transmission unit that transmits the driving force from the belt to the roller, and the driving force transmitted from the driving shaft is transmitted to the roller to rotate in the delivery direction; Drive It is characterized by comprising a transmission mechanism.

  In the image forming apparatus of the present invention configured as described above, the roller held on one end side of the holding member is driven to rotate to send the recording sheet placed on the tray toward the image forming unit. The image forming unit forms an image on the recording sheet. Here, the driving force from the motor transmitted by the drive shaft is transmitted to the roller via the following driving force transmission mechanism. That is, the driving force transmission mechanism is provided on the holding member, and a belt erected along the direction from the other end to the one end, and a first transmission that transmits the driving force from the driving shaft to the belt. And a second transmission unit that transmits the driving force from the belt to the roller. When the driving force transmission mechanism is configured using the belt erected as described above, the driving force transmission mechanism and the holding member are perpendicular to the thickness direction (the direction from the other end to the one end, and The thickness can be reduced in a direction perpendicular to the rotation axis of the roller. Therefore, the image forming apparatus of the present invention can be reduced in size favorably.

  The holding member includes a first holding member that rotatably holds the roller, and a mounting portion to which the first holding member is attached on the one end side on the side where the roller receives a reaction force from the recording sheet. And a second holding member.

  In this case, the first holding member that rotatably holds the roller is attached to the attachment portion of the second holding member from the side where the roller receives a reaction force from the recording sheet. Therefore, the recording sheet can be sent out more stably by preventing the roller from dropping off due to the reaction force.

  In this case, the first transmission unit includes a first rotating body that is held by the second holding member, the belt is installed on the belt, and transmits a driving force to the belt. The belt includes a second rotating body that is held by a first holding member and transmits a driving force from the belt, and the first holding member and the second holding member are arranged along a direction in which the belt is installed. And restricting portions for positioning the rollers in the direction in which the belt is erected by contacting each other.

  In this case, a force is applied between the first holding member and the second holding member due to the belt being installed between the second rotating body and the first rotating body provided in each of the first holding member and the second holding member. The positions of both are regulated by the contact of the restricting portions. For this reason, the position of the roller is positioned at an appropriate position. In addition, by defining the positions of the first holding member and the second holding member in this manner, the interval between the first rotating body and the second rotating body can be set to an appropriate interval according to the belt. it can. Therefore, for example, when both the first rotating body and the second rotating body are toothed pulleys and the belt is a toothed belt, tooth skipping of the belt can be suppressed. The roller can be driven more stably.

  In addition, the belt has one end side laid on a rotating body that rotates integrally with the rotation shaft of the roller, and a pair of rollers that can be inserted from both ends of the rotation shaft. The end surface to be configured may constitute a flange of the rotating body by inserting the rollers into the rotating shaft until the end surfaces come into contact with the rotating body.

  In this case, a pair of rollers are respectively inserted from both ends of the rotating shaft, and end surfaces facing each other are brought into contact with a rotating body that rotates integrally with the rotating shaft of the roller, thereby rotating the rotating body with a flange. As described above, it is possible to suppress the belt from being detached from the rotating body. In addition, this operation can be performed in an arbitrary order before and after the installation of the belt with respect to the rotating body. Therefore, in this case, the assembly operation of the image forming apparatus can be facilitated to reduce the manufacturing cost, and the belt can be prevented from coming off well.

1 is a perspective view illustrating an appearance of an image forming apparatus to which the present invention is applied. 2 is a central cross-sectional view schematically showing a configuration of a main part of the image forming apparatus. FIG. It is a perspective view showing a part of said principal part when a tray exists in a mounting position. It is a top view showing the structure of the supporting member of the said part. It is ABCD step sectional drawing of FIG. 4 showing the structure and operation | movement of the supporting member. It is a disassembled perspective view showing the structure of the paper feed arm of the part. It is the bottom view and sectional drawing showing the structure of the paper feeding arm.

[Entire configuration of image forming apparatus]
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view illustrating an appearance of an image forming apparatus 10 to which the present invention is applied. In the following description, the upper side of the state where the image forming apparatus 10 is installed (the state of FIG. 1) is the upper side, the side where the display unit 13 is provided is the front side, and the image forming apparatus 10 is the front side. The right side seen from the (front side) is the right side.

  The image forming apparatus 10 has a substantially rectangular parallelepiped shape including a lower printer unit 11 and an upper scanner unit 12, and is a multi-function machine having print, scan, and copy functions. The scanner unit 12 has an arbitrary configuration.

  The printer unit 11 is controlled by a control unit (not shown), and forms an image on a recording sheet 50 (see FIG. 2: an example of a recording sheet) placed on the tray 15. The recording paper 50 is a recording paper, glossy paper, postcard, sealed letter, or the like.

  As shown in FIG. 1, the tray 15 is accommodated in a lower portion of the printer unit 11 so that the tray 15 can be drawn forward from an opening 19 provided on the front surface of the printer unit 11. The tray 15 has a flat rectangular parallelepiped outer shape with an upper opening. A paper discharge receptacle 18 is provided on the upper portion of the tray 15.

  FIG. 2 is a central cross-sectional view schematically showing a configuration of a main part of the image forming apparatus 10. As shown in FIG. 2, the recording paper 50 is placed on the upper surface of the bottom 16 of the tray 15 (hereinafter referred to as a placement surface 16 </ b> A). The rear wall 17 of the tray 15 extends rearward and obliquely upward from the rear end of the bottom portion 16. A recording sheet 50 fed out by a feeding unit 20 to be described later is guided by the rear wall 17 and heads rearward and obliquely upward.

  The printer unit 11 further includes an ink jet recording type recording unit 24 (an example of an image forming unit) that discharges ink droplets onto the recording sheet 50 fed by the feeding unit 20 to form an image on the recording sheet 50; A route switching unit 41 and the like are provided above the tray 15. The recording unit 24 is not limited to the ink jet system, and various recording systems such as an electrophotographic system can be applied.

  As shown in FIG. 2, the feeding unit 20 is provided above the tray 15 and below the recording unit 24. The feeding unit 20 includes a paper feed roller 25 (an example of a roller), a paper feed arm 26, and the like. The paper feed roller 25 is rotatably held at the tip of the paper feed arm 26. The paper feed arm 26 swings in the direction of arrow A about a support shaft 28 provided at the base end. Thereby, the paper feed roller 25 can be brought into contact with and separated from the placement surface 16A. For this reason, the paper feed arm 26 swings in accordance with the remaining amount of the recording paper 50 placed on the placement surface 16A, so that the paper feed roller 25 is moved to the recording paper 50 placed on the placement surface 16A. Can always contact. The drive mechanism of the paper feed roller 25 will be described in detail later.

  The paper feed roller 25 separates the recording paper 50 from the other recording paper 50 in a state of being in contact with the uppermost recording paper 50 among the recording papers 50 placed on the placement surface 16A. , Supplied to the curved path 65A. Here, inside the printer unit 11, a conveyance path 65 is formed from the front end (rear end portion) of the tray 15 through the recording unit 24 to the paper discharge receiver 18. The conveyance path 65 includes a curved path 65 </ b> A formed between the leading end of the tray 15 and the first conveyance roller 60, and a paper discharge path 65 </ b> B formed between the first conveyance roller 60 and the paper discharge receiver 18. It is divided.

  The curved path 65 </ b> A is a curved path extending from the vicinity of the upper end of the rear wall 17 of the tray 15 to the recording unit 24. The curved path 65 </ b> A is generally formed in an arc shape centering on the inside of the printer unit 11. The recording paper delivered from the tray 15 by the paper feed roller 25 is curved along the conveyance direction (the direction indicated by the one-dot chain line in FIG. 2) along the curved path 65A, and is recorded by the first conveyance roller 60 and the pinch roller 61. The paper 50 is guided to the clamping position. The curved path 65A is partitioned by an outer guide member 33 and an inner guide member 34 facing each other with a predetermined interval. Note that the outer guide member 33 and the inner guide member 34, as well as guide members 31, 32, 82, and 83, which will be described later, all extend in the direction perpendicular to the paper surface (left and right direction) in FIG.

  The paper discharge path 65 </ b> B is a linear path extending from the position where the recording paper 50 is held by the first transport roller 60 and the pinch roller 61 to the paper discharge receiver 18. The recording paper 50 is guided in the direction indicated by the alternate long and short dash line through the paper discharge path 65B. The paper discharge path 65B is partitioned by the recording unit 24 and the platen 42 that face each other at a predetermined interval at a location where the recording unit 24 is provided. In addition, the paper discharge path 65B is partitioned by an upper guide member 82 and a lower guide member 83 that face each other at a predetermined interval at a location where the recording unit 24 is not provided.

  In the printer unit 11, a branch position 36 is set on the downstream side of the recording unit 24 and on the downstream side of the second conveyance roller 62 described later. The recording paper 50 conveyed through the paper discharge path 65B is switched back downstream of the branch position 36 during double-sided image recording, and is conveyed toward a reverse conveyance path 67 described later.

  The recording unit 24 is disposed above the tray 15. The recording unit 24 reciprocates in the left-right direction (the direction perpendicular to the paper surface in FIG. 2). A platen 42 for holding the recording paper 50 horizontally is provided below the recording unit 24. In the reciprocating movement in the left-right direction, the recording unit 24 ejects ink supplied from an ink cartridge (not shown) as ink droplets onto the recording paper 50 conveyed on the platen 42 from the nozzles 39. As a result, an image is formed on the recording paper 50.

  The recording paper 50 which is fed onto the platen 42 by the first conveying roller 60 and the pinch roller 61 and on which the image is formed by the recording unit 24 is further conveyed by the second conveying roller 62 and the spur 63. On the further downstream side of the second conveyance roller 62 and the spur 63, the third conveyance roller 45 and the spur 46 are provided on the downstream side of the branch position 36.

  The third transport roller 45 is rotationally driven in the forward rotation direction or the reverse rotation direction as follows. For example, when single-sided recording is performed, the third transport roller 45 is rotated in the forward rotation direction. As a result, the recording paper 50 is sandwiched between the third transport roller 45 and the spur 46 and transported downstream, and is ejected to the paper ejection receptacle 18. On the other hand, when double-sided image recording is performed, the rotation direction of the third conveyance roller 45 is switched from the normal rotation direction to the reverse rotation direction with the third conveyance roller 45 and the spur 46 sandwiching the rear end portion of the recording paper 50. It is done. Thereby, the recording paper 50 is conveyed in the direction opposite to the direction from the first conveying roller 60 to the third conveying roller 45, and is conveyed toward the reverse conveying path 67 described later by the path switching unit 41 described below. .

[Configuration of route switching unit]
As shown in FIG. 2, the path switching unit 41 is disposed on the paper discharge path 65 </ b> B between the second transport roller 62 and the branch position 36, and the auxiliary rollers 47 and 48, the flap 49, and the support shaft 87 are connected. I have. A support shaft 87 extending in the left-right direction is provided on a frame or the like of the printer unit 11. The flap 49 is pivotally supported on a support shaft 87, and an auxiliary roller 47 and an auxiliary roller 48 are pivotally supported on the flap 49. Since the auxiliary rollers 47 and 48 are in contact with the recording surface of the recording paper 50, the auxiliary rollers 47 and 48 are formed in a spur shape like the spur 63 and the spur 46.

  The flap 49 has a discharge position (position indicated by a broken line in FIG. 2) positioned above the lower guide member 83 around the support shaft 87, and an end portion 49A on the discharge receiver 18 side at a branch position 36. It rotates between the inverted posture (the posture shown by the solid line in FIG. 2) that enters further downward. When the flap 49 is in the discharge posture, the recording paper 50 that has passed through the recording unit 24 is further conveyed to the downstream side. When the flap 49 is in the reverse posture, the third conveyance roller 45 is reversed to switch to the reverse conveyance path 67. Back transported. The flap 49 is in an inverted posture due to its own weight in a normal state, but is rotated to change its posture to the discharge posture by being lifted by the recording paper 50 conveyed through the paper discharge path 65B. Further, when the trailing edge of the recording paper 50 passes through the auxiliary roller 47, the flap 49 rotates by its own weight and changes its posture from the discharge posture to the reverse posture. The flap 49 may be configured to be rotated by a motor or the like.

  The reverse conveyance path 67 is branched from the paper discharge path 65B at the branch position 36, passes the lower side of the recording unit 24 and the upper side of the feeding unit 20, and the curved path 65A at the merging position 37 upstream of the recording unit 24. To join. After the trailing edge of the recording paper 50 passes through the auxiliary roller 47 and the flap 49 changes its posture to the reverse orientation, when the third transport roller 45 is driven to rotate in the reverse rotation direction, the recording paper 50 is indicated by a two-dot chain line. As shown, the reverse conveying path 67 is conveyed toward the merging position 37. Further, the reverse conveyance path 67 is partitioned on the upper side by the second guide member 32 and on the lower side by the first guide member 31.

  The reverse conveyance path 67 is provided with a fourth conveyance roller 68 and a driven roller 69. The fourth transport roller 68 is disposed at a position facing the driven roller 69 from below in the reverse transport path 67. When the recording paper 50 conveyed to the reverse conveyance path 67 by the third conveyance roller 45 is sandwiched between the fourth conveyance roller 68 and the driven roller 69, the fourth conveyance roller 68 reversely conveys the recording paper 50. It is conveyed along the path 67 toward the merge position 37. As a result, the recording paper 50 is sent onto the curved path 65 </ b> B via the joining position 37, and images are formed on both sides of the recording paper 50.

[Supporting mechanism for feeding section]
As shown in FIG. 3, the paper feed arm 26 is a resin support that is assembled to the main body of the image forming apparatus 10 (the entire member integrally assembled with the platen 42, guide members 31, 32, 82, 83, and the like). The member 70 is swingably supported. Note that the upper surface of the support member 70 constitutes a part of the first guide member 31 described above, and further, a pair of the fourth conveying rollers 68 described above is supported on the upper surface so as to be rotatable on the left and right.

  Further, on the left side surface of the tray 15, a cam crest 15A having different heights along the advancing / retreating direction (front-rear direction) of the tray 15 is provided, and the cam crest 15A swings integrally with the paper feed arm 26. The tip of the moving lever 26 </ b> B is configured to be able to contact with the cap 27. When the tray 15 is disposed at the mounting position where the recording paper 50 can be sent to the recording unit 24 as described with reference to FIG. 2, as shown in FIG. 3, the cap 27 is in contact with the cam crest 15A. In addition, as described above, the paper feed roller 25 can always contact the recording paper 50 on the placement surface 16A. When the tray 15 is pulled out for replenishment of the recording paper 50 from this mounting position, the cap 27 rides on the cam crest 15A and the lever 26B swings upward. Then, in conjunction with this, the paper feed arm 26 also swings upward, and the paper feed roller 25 is separated from the placement surface 16A of the tray 15 or the recording paper 50 placed on the placement surface 16A. Therefore, the tray 15 can be easily pulled out.

[Driving mechanism drive mechanism]
FIG. 4 is a plan view showing the configuration of the support member 70, and FIG. 5 is an ABCD step sectional view thereof. In FIG. 4, for convenience of explanation, a driven roller 69 that faces one (left side) fourth transport roller 68 is also illustrated.

  As shown in FIG. 5, the support member 70 swings around the sun gear 81 while maintaining the sun gear 81 rotating integrally with the drive shaft 81 </ b> A (see FIG. 4) and the sun gear 81. A planetary gear mechanism 80 (pendulum gear mechanism) including a planetary gear 82 is provided. The planetary gear 82 swings around the sun gear 81 while maintaining the meshed state by being rotatably mounted on a lever 85 provided so as to be swingable around the drive shaft 81A. Further, the planetary gear mechanism 80 is covered with a cover 71 provided on the upper end surface of the support member 70 so as not to affect the conveyance of the recording paper 50.

  When the sun gear 81 rotates counterclockwise in FIG. 5, the planetary gear 82 also swings in the same direction, and as shown in FIG. 5A, the input gear 89 that is rotatably mounted on the aforementioned support shaft 28. Mesh with. The input gear 89 meshes with a gear 91 </ b> A (see FIG. 6) provided at the base end portion of the paper feed arm 26 and rotating integrally with a toothed pulley 91 (an example of a first rotating body). The toothed pulley 91 is provided with a toothed belt 93 (an example of a belt) between a toothed pulley 92 (an example of a second rotating body and a rotating body) that rotates integrally with the paper feed roller 25. For this reason, the paper roller 25 can be rotated clockwise in FIG. 5, that is, in the feeding direction of the recording paper 50 by the counterclockwise rotation of the sun gear 81.

  Conversely, when the sun gear 81 rotates in the clockwise direction in FIG. 5, the planetary gear 82 is moved away from the input gear 89 in the same direction as shown in FIG. Not. The mechanism from the toothed pulley 91 to the toothed pulley 92 corresponds to an example of a driving force transmission mechanism, of which the toothed pulley 91 is the first transmission unit, the toothed pulley 92 is the second transmission unit, respectively. Equivalent to.

  Further, as shown in FIG. 5, a re-conveying drive shaft 68 </ b> A is supported on the support member 70. The re-conveyance drive shaft 68A drives the fourth conveyance roller 68 via a gear 68B that rotates integrally with the re-conveyance drive shaft 68A.

  FIG. 6 is an exploded perspective view showing the configuration of the paper feed arm 26 in detail. 7A is a bottom view showing the configuration of the paper feed arm 26, FIG. 7B is a cross-sectional view taken along line FF of FIG. 7A, and FIG. 7C is FIG. It is the figure which abbreviate | omitted the toothed belt 93 in B).

  As shown in FIG. 6, the paper feed roller 25 is attached to the tip of the paper feed arm 26 via a roller holder 95 that rotatably holds the paper feed roller 25. That is, the roller holder 95 and the paper feed arm 26 correspond to a holding member, of which the roller holder 95 corresponds to a first holding member and the paper feed arm 26 corresponds to a second holding member.

  The rotating shaft 92A of the toothed pulley 92 has a D-shaped cross section at both ends, and a hole 25A in which a portion corresponding to the tip is formed in a D-shaped section at the rotation center of the paper feed roller 25 is also provided. Is formed. The paper feed roller 25 is configured to have a large diameter and feed a recording paper 50. The roller body 25B is disposed closer to the toothed pulley 92 (hereinafter referred to as the inner side) than the roller main body 25B when mounted on the rotary shaft 92A. A small-diameter portion 25C, and a flange 25D formed on the inner edge of the small-diameter portion 25C. The roller holder 95 includes a pair of bearing portions 95A that rotatably support the small-diameter portions 25C of the paper feed rollers 25 mounted on the rotary shaft 92A from both ends. The bearing portion 95A is formed in an arc shape with a central angle of about 270 ° opened at the lower rear side (that is, the side receiving the reaction force from the recording paper 50), and the portion of the bearing portion 95A is the left and right sides of the roller holder 95. It protrudes from the end face.

  A mounting surface 26E (an example of a mounting portion) configured in an arc shape with a central angle of about 180 ° opened at the front end of the paper feeding arm 26 (that is, the side receiving the reaction force from the recording paper 50) is formed. Has been. The roller holder 95 is mounted (attached) to the front end of the paper feed arm 26 by fitting a bearing portion 95A protruding from the left and right end surfaces thereof to the mounting surface 26E.

  As shown in FIGS. 6 and 7, a wall surface 95 </ b> B (an example of a regulating portion) facing the toothed pulley 91 side perpendicular to the erection direction of the toothed belt 93 is formed on the inner surface of the pair of bearing portions 95 </ b> A. The paper feed arm 26 is also formed with a wall surface 26F (an example of a restricting portion) that faces and contacts the wall surface 95B when the roller holder 95 is mounted. Further, the roller holder 95 has an extension portion 95C extending from the lower surface of the bearing portion 95A in the proximal direction of the paper feed arm 26, and the paper feed arm 26 is part of the extension portion 95C when the roller holder 95 is mounted. A wall surface 26G that contacts and positions the extension portion 95C is formed.

  For this reason, when the roller holder 95 is attached to the paper feed arm 26, the roller holder 95 is in contact with the paper feed arm 26 due to the contact between the wall surface 95B and the wall surface 26F and the contact between the extension 95C and the wall surface 26G. Positioned. In addition, when the toothed belt 93 is installed between the toothed pulleys 91 and 92, the contact state between the wall surface 95B and the wall surface 26F is stably maintained by the tension applied from the toothed belt 93. Further, when the paper feed rollers 25 are mounted on the rotating shaft 92A of the toothed pulley 92 from both ends, the inner end surfaces of the flanges 25D of the paper feed rollers 25 are on the left and right ends of the toothed pulley 92, as shown in FIG. Contact the surface. The flange 25 </ b> D has a larger diameter than the toothed pulley 92, and the flange 25 </ b> D contacts the left and right end surfaces in this manner, thereby preventing the toothed belt 93 from being detached from the toothed pulley 92. it can.

[Effects of this embodiment and its modifications]
As described above, in the image forming apparatus 10 of this embodiment, the mechanism for transmitting the driving force from the proximal end side to the distal end side of the paper feeding arm 26 to drive the paper feeding roller 25 is the toothed pulley 91, A toothed belt 93 laid between 92 is used. For this reason, the mechanism and the paper feed arm 26 can be thinned in the thickness direction (a direction perpendicular to the direction from the base end to the tip and perpendicular to the rotation axis of the paper feed roller 25). it can. Therefore, the image forming apparatus 10 of the present embodiment can be favorably downsized. In particular, in an image forming apparatus that is equipped with a mechanism such as the reverse conveyance path 67 and supports double-sided image recording like the image forming apparatus 10 of the present embodiment, there is a strong demand for downsizing. Therefore, in this embodiment, the effect of the above-mentioned miniaturization appears more remarkably.

  Further, as described above, the roller holder 95 that rotatably holds the paper feed roller 25 is attached to the tip of the paper feed arm 26 from the side where the paper feed roller 25 receives the reaction force from the recording paper 50. The sheet feeding roller 25 is prevented from falling off due to the reaction force, and the recording paper 50 can be sent out more stably. Moreover, the positional relationship between the roller holder 95 and the paper feed arm 26 is defined by the contact of the wall surfaces 95B and 26F as described above, and the toothed belt 93 is interposed between the toothed pulleys 91 and 92 provided in both. The force of approaching each other acts by being installed. Therefore, the interval between the toothed pulleys 91 and 92 can be set to an appropriate interval according to the toothed belt 93, and the tooth skipping of the toothed belt 93 can be suppressed. Therefore, the image forming apparatus 10 can drive the paper feed roller 25 more stably.

  Further, in the image forming apparatus 10, the pair of paper feed rollers 25 are inserted from both ends of the rotation shaft 92 </ b> A, and the flange 25 </ b> D is brought into contact with the toothed pulley 92. As a result, the toothed belt 93 can be prevented from coming off. Moreover, this operation can be performed in any order before and after the installation of the toothed belt 93 with respect to the toothed pulley 92. Therefore, in the present embodiment, the assembly operation of the image forming apparatus 10 can be facilitated to reduce the manufacturing cost, and the toothed belt 93 can be satisfactorily prevented from coming off.

  In addition, this invention is not limited to the said embodiment at all, It can implement with a various form in the range which does not deviate from the summary of this invention. For example, in the above-described embodiment, the toothed pulley 92 as an example of the second rotating body and the rotating body rotates integrally with the paper feed roller 25, but the rotation of the toothed pulley 92 is further fed via a gear or the like. 25 may be transmitted. Further, the longitudinal direction of the sheet feeding arm 26 (the direction from the base end to the tip end) and the installation direction of the toothed belt 93 may not be completely parallel. Further, the sheet feeding arm 26 may not be able to swing, and various mechanisms can be employed as a mechanism for transmitting the driving force of the motor to the toothed pulley 91. Furthermore, the first rotating body, the second rotating body, and the rotating body are not limited to the toothed pulleys, and various rotating bodies can be employed. For example, a general pulley without teeth may be used, or a roller whose surface is a friction surface may be used.

DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus 11 ... Printer part 15 ... Tray 20 ... Feeding part 24 ... Recording part 25 ... Paper feed roller 25B ... Roller main body 25C ... Small diameter part 25D ... Flange 26 ... Paper feed arm 26E ... Mounting surface 26F, 26G, 95B ... Wall 39 ... Nozzle 42 ... Platen 50 ... Recording paper 70 ... Support member 80 ... Planetary gear mechanism 81 ... Sun gear 81A ... Drive shaft 82 ... Planetary gear 85 ... Lever 89 ... Input gear 91, 92 ... Toothed pulley 93 ... Toothed belt 95 ... Roller holder 95A ... Bearing part 95C ... Extension part

Claims (4)

A tray on which recording sheets are placed;
An image forming unit for forming an image on the recording sheet;
A roller that rotates and feeds the recording sheet placed on the tray toward the image forming unit;
Holding the roller rotatably at one end side, and a holding member supported at the other end side by a support member provided above the tray;
A drive shaft for transmitting drive force from the motor;
A belt provided on the holding member and erected along a direction from the other end to the one end, a first transmission unit that transmits a driving force from the driving shaft to the belt, and a driving force from the belt A drive force transmission mechanism that transmits the drive force transmitted from the drive shaft to the roller and rotates the roller in the delivery direction.
An image forming apparatus comprising: The holding member is
A first holding member for rotatably holding the roller;
A second holding member provided on the one end side with an attachment portion to which the first holding member is attached on the side where the roller receives a reaction force from the recording sheet;
The image forming apparatus according to claim 1, further comprising: The first transmission portion includes a first rotating body that is held by the second holding member and on which the belt is installed and transmits a driving force to the belt, and the second transmission portion is connected to the first holding member. A second rotating body that holds the belt and transmits a driving force from the belt;
The first holding member and the second holding member are each provided with a regulating portion that positions the roller in the belt erection direction by abutting each other along the belt erection direction. The image forming apparatus according to claim 2. The one end side of the belt is installed on a rotating body that rotates integrally with a rotation shaft of the roller,
A pair of the rollers are provided so as to be insertable from both ends of the rotating shaft,
The end faces of the rollers facing each other constitute a flange of the rotating body by inserting the rollers into the rotating shaft until the end faces come into contact with the rotating body. The image forming apparatus according to any one of 1 to 3.

Images