JP4289684B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that includes a sheet feeding device that conveys a recording sheet loaded so as to lean against a sheet feeding tray and forms an image while conveying the recording sheet.

  2. Description of the Related Art Conventionally, as an image forming apparatus that forms (prints) an image on a recording sheet loaded so as to lean against a paper feed tray, for example, as disclosed in Patent Document 1, an openable / closable cover also serves as a paper feed tray. It is known that recording paper is stacked on an open cover, and the leading end of the recording paper is pressed against a paper feed roller by a pressing plate with a predetermined pressure. In this device, the pressing plate is configured to be rotatable in the vertical direction around the support shaft, and is urged upward by a push-up spring.

  However, in this apparatus, when a plurality of paper feed rollers are provided on the same axis and there is an error in the size and shape of the component parts, or there is an error in assembling the parts, the pressing plate Is not biased according to the individual paper feed rollers, the distance between the paper feed roller and the pressing plate may differ depending on the paper feed roller. Therefore, the force with which the paper feeding roller and the pressing plate sandwich the recording paper differs depending on the paper feeding roller, and there is a possibility that the recording paper skews or skews during paper feeding.

  In the technique of Patent Document 2, a separation pad for separating one recording sheet from a stacked recording sheet is pressed against a sheet feeding roller by a pad-attached pressure plate. In this apparatus, two paper feed rollers are arranged on the same axis. In this apparatus, a guide is further provided on the paper feed tray so as to be movable in the recording paper width direction, and a driven roller is pivotally supported by a bracket extending from the guide toward the center of the recording paper width direction. The paper feed roller is disposed upstream of the driven roller in the recording paper transport path. In this device, when the guide is moved according to the width dimension of the recording paper, the driven roller is moved by the same stroke as the moving stroke, thereby correcting the skew of the recording paper with reference to both side edges of the recording paper front end. It is intended.

  However, in this apparatus, when there is an error in the size and shape of the component parts or when there is an error when assembling the parts, the separation pad is energized according to each of the two paper feed rollers. As a result, the interval between the paper feed roller and the separation pad may differ depending on the paper feed roller. For this reason, there is a possibility that a skew of the recording paper occurs during paper feeding. When skew occurs during paper feeding, it is difficult to correct the skew even with the guide and the driven roller.

  Further, in the technique of Patent Document 3, it is known that a pressure plate on which recording paper is stacked is pressed against a paper feeding roller by the action of a pressure plate spring and the uppermost recording paper is fed. In this apparatus, two paper feed rollers are arranged on the same axis. However, in this apparatus, it is difficult to prevent the skew of the recording paper at the time of paper feeding for the same reason as the technique of Patent Document 2.

Further, in Patent Document 4, the recording paper is not placed on the paper feed tray but placed horizontally on the paper feed tray. In this apparatus, a paper feed roller disposed above the paper feed tray picks up and feeds the uppermost recording paper placed on the paper feed tray. The sensor detects the skew of the recording paper fed and conveyed, and outputs a correction signal for correcting the skew. However, with this apparatus, it is difficult to prevent the skew of the recording paper during feeding.
Japanese Patent No. 3197125 JP 05-294465 A JP-A-2005-154087 Japanese Patent Laid-Open No. 11-263465

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus including a paper feeding device that can prevent skew feeding of recording paper during paper feeding.

  In order to achieve the above object, the invention according to claim 1 is arranged on the housing and the back of the housing so that the portion on which the recording paper is placed is inclined upward and forwarded inside the housing. A paper feed tray that is loaded so that the recording paper to be stood is stood up, a paper feed device having a recording paper transport mechanism that transports the recording paper loaded in the paper feed tray into the housing, and the housing A carriage having a recording head which is disposed inside and discharges ink toward a lower recording sheet conveyed by the recording sheet conveying mechanism, and reciprocally moves the carriage in a main scanning direction substantially orthogonal to the recording sheet conveying direction. In the image forming apparatus including the driving mechanism, the recording paper transport mechanism includes two paper feeding rollers that feed the recording paper placed on the paper feeding tray into the housing, and the two paper feeding papers. The roller is separated and pivotally supported. A rotating shaft disposed in parallel with the main scanning direction; and urging means for supporting both ends of the rotating shaft and urging the sheet feeding roller and the rotating shaft in the sheet feeding tray direction; It is provided on the paper tray side, and is composed of a cylindrical main body portion and shaft portions projecting from both end portions of the main body portion, and is paired with each of the two paper feed rollers. The main body portion is disposed so as to be substantially parallel to the main scanning direction, the main body portion includes two pinch rollers that sandwich the recording paper with the paper feed roller, and the paper feed tray includes the paper feed tray. A storage portion that is recessed at a mounting portion of the pinch roller in the paper tray and stores a part of a main body portion of the pinch roller; and a bearing portion to which the shaft portion of the pinch roller is engaged. Is a leaf spring member that urges the body portion of the pinch roller in the direction of the paper feed roller. The leaf spring member bends in a state where the paper feed roller and the pinch roller sandwich the recording paper, and the intervals between the two pairs of the paper feed roller and the pinch roller become substantially equal. The skew of the recording paper during feeding is prevented.

  The invention according to claim 2 is the housing and the back of the housing, the part on which the recording paper is placed is inclined so as to face upward and forward, and the recording paper conveyed into the housing is leaned against A sheet feeding tray loaded as described above, a recording sheet conveying mechanism for conveying the recording sheet loaded in the sheet feeding tray into the housing, and an image for forming an image on the recording sheet conveyed in a predetermined direction In the image forming apparatus including the forming unit, the recording paper transport mechanism includes a plurality of paper feeding rollers that feed the recording paper placed on the paper feeding tray to the inside of the housing, and the paper feeding tray side. A cylindrical main body portion and a shaft portion projecting from both side end portions of the main body portion, each paired with the plurality of paper feed rollers, the axial direction of which is the main scanning direction Are arranged so as to be substantially parallel to each other, and the main body is between the paper feed roller and A plurality of pinch rollers sandwiching the recording paper, the paper feed tray is formed integrally with the paper feed tray, and urges the main body of the pinch roller toward the paper feed roller The plate spring member has a leaf spring member, and the leaf spring member bends in a state where the paper feed roller and the pinch roller sandwich the recording paper. Thus, the skew feeding of the recording paper during feeding is prevented.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the number of the feed rollers and the pinch rollers is two.

  According to the first to third aspects of the present invention, the paper feed roller and the pinch roller sandwich the recording paper, that is, the pinch roller is pressed by the paper feed roller through the recording paper, Since the storage portion, which is a leaf spring member, bends, the intervals between the plurality of pairs of pinch rollers and paper feed rollers can be made substantially equal. Therefore, the recording paper can be pinched reliably in each pair. Therefore, it is possible to prevent the skew of the recording paper when feeding.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a sheet feeding device and an image forming apparatus including the sheet feeding device according to the present embodiment. The image forming apparatus (hereinafter referred to as a printer) 1 includes a paper feed device 2 that transports a recording paper P and a carriage on which an ink cartridge 3 that ejects ink onto the recording paper P transported by the paper feed device 2 is mounted. 4 and a drive mechanism 5 that reciprocally moves the carriage 4 in a main scanning direction (indicated by an arrow A) substantially orthogonal to the recording paper conveyance direction. The recording paper conveyance direction is the same as the sub-scanning direction (indicated by arrow B). The image forming method in the printer 1 is an ink jet method. The ink cartridge 3, the carriage 4, and the drive mechanism 5 constitute an image forming unit.

  The paper feeding device 2 includes a housing 20, a paper feeding tray 21 in which recording paper P is loaded, and a recording paper transport mechanism (recording paper) that transports the recording paper P loaded in the paper feeding tray 21 into the housing 20. Transport mechanism) 22. A paper feed tray 21 is disposed on the back of the housing 20, and a paper discharge tray 30 for discharging the printed recording paper P is provided below the front surface of the housing 20. The paper feed tray 21 is made of a resin member, and is disposed so as to be inclined so that the portion on which the recording paper P is placed faces upward and forward. The recording paper P to be transported is loaded on the paper feed tray 21 so as to lean up against it. The side edge of the recording paper P is guided by two guides (not shown) provided on the paper feed tray 21 so as to be slidable in the main scanning direction, and positioned at a predetermined position on the paper feed tray 21. Loaded.

  Inside the housing 20 are a recording paper transport mechanism 22, an ink cartridge 3, a carriage 4 on which the ink cartridge 3 is mounted, a driving mechanism 5 that applies a driving force to the carriage 4 to reciprocate, and a rear surface of the carriage 4. A shaft 6 whose main scanning direction is arranged in the longitudinal direction on the side, and an encoder scale 7 used for detecting the position of the carriage 4 in the main scanning direction and arranged on the housing 20 along the main scanning direction; A control circuit 8 for controlling various operations of the printer 1 is provided.

  The recording paper transport mechanism 22 includes two paper feeding rollers 22a for feeding the recording paper P from the paper feeding tray 21 to the inside of the housing 20, a rotating shaft 22b that supports the paper feeding roller 22a, and a rotating shaft 22b. A pair of arms (biasing means) 22c for urging the sheet feeding roller 22a and the rotating shaft 22b in the direction of the sheet feeding tray 21, and the sheet feeding roller on the sheet feeding tray 21 side. 22a and a pinch roller (not shown) provided at a corresponding position. The rotating shaft 22b is supported in parallel with the main scanning direction by axially supporting the two paper feeding rollers 22a while separating them according to the width of the recording paper P. The upper end of the arm 22c supports both end portions of the rotating shaft 22b. The arm 22c is configured to be rotatable about the lower end portion, and rotates in the direction of the paper feed tray 21 when the recording paper P loaded in the paper feed tray 21 is conveyed into the housing 20. Then, the two paper feed rollers 22a are pressed against the recording paper P. This structure in the paper feeder 2 will be described in detail later.

  Further, the recording paper transport mechanism 22 has an image formed thereon with a transport roller for transporting the recording paper P fed into the housing 20 by the paper feed roller 22a in the sub-scanning direction inside the housing 20. The recording paper P includes a paper discharge roller that discharges the recording paper P to the paper discharge tray 30, a motor that is a power source, and the like. A conveyance roller, a paper discharge roller, and a motor are not shown. The motor is configured to rotate the paper feed roller 22a, the transport roller, and the paper discharge roller via, for example, a gear.

  The ink cartridge 3 has an ink tank for storing ink therein. A recording head 3 a having a plurality of nozzles for discharging the ink stored in the ink tank is provided on the lower surface of the ink cartridge 3. The ink cartridge 3 is disposed in a space provided in the carriage 4, and in this state, the recording head 3 a ejects ink toward the lower recording paper conveyed by the recording paper conveyance mechanism 22. .

  The carriage 4 is slidably fitted to the shaft 6 and is connected to a part of the belt 5a of the drive mechanism 5 as described later, and is arranged so as to be movable along the shaft 6 in the main scanning direction. A photocoupler is mounted on the carriage 4, and the photocoupler scans an encoder scale 7 having a predetermined resolution so that the position of the carriage 4 in the main scanning direction can be detected. .

  The drive mechanism 5 includes, for example, an annular belt 5a disposed along the main scanning direction on the casing 20 of the printer 1, a DC motor 5b for rotating the belt 5a, and the like. A part of the belt 5 a is connected to the rear of the carriage 4. The drive mechanism 5 reciprocates in the main scanning direction by applying a driving force to the carriage 4 by rotating the belt 5a by the DC motor 5b. The drive mechanism 5 is not limited to this configuration.

  The control circuit 8 is controlled by software such as a device driver that operates on an external personal computer, for example. The control circuit 8 forms an image on the recording paper P by controlling the recording paper transport mechanism 22, the recording head 3a, the driving mechanism 5 and the like based on data and commands transmitted from the personal computer, for example. Execute the print function. Hereinafter, the sheet feeding device 2 will be described in detail.

  2 and 3 show the configuration of the paper feeding device 2 in detail. The paper feed device 2 includes a paper feed tray 21 and a recording paper transport mechanism 22, and the recording paper transport mechanism 22 includes two paper feed rollers 22a, a rotary shaft 22b that supports these shafts, and a rotary shaft 22b. The arm 22c that supports the shaft and the two pinch rollers 23 provided on the paper feed tray 21 side.

  The pinch roller 23 has a cylindrical main body portion 23 a and shaft portions 23 b that protrude from both end portions of the main body portion 23 a and is attached to the paper feed tray 21. The pinch roller 23 is arranged so that its axial direction is substantially parallel to the main scanning direction. The two pinch rollers 23 are paired with each of the two paper feed rollers 22a. When the recording paper P loaded in the paper feed tray 21 is conveyed into the housing 20, the main body 23a feeds the paper. The recording paper P is sandwiched between the rollers 22a. After the recording paper P is sequentially conveyed and all of the recording paper P loaded in the paper feeding tray 21 is conveyed, the pinch roller 23 comes into contact with the paper feeding roller 22a. Can be prevented from being worn away by contact with

  The paper feed tray 21 is provided with a paper feed tray main body 21a, a recessed portion at the attachment portion of the pinch roller 23 in the paper feed tray 21, and a storage portion 21b for storing a part of the main body portion 23a of the pinch roller 23; And a bearing portion 21c with which the shaft portion 23b of the pinch roller 23 is engaged. The storage portion 21b is configured by a leaf spring member that urges the main body portion 23a of the pinch roller 23 in the direction of the paper feed roller 22a. For example, the leaf spring member is bent or curved in accordance with the size and shape of the pinch roller 23 so that a part of the front surface of the paper feed tray main body 21a is convex toward the back surface side. . Further, the leaf spring member is formed by providing a U-shaped slit in the sheet feeding tray main body 21a so that the base end is disposed above. Therefore, the leaf spring member can be bent in the front-rear direction (left-right direction in FIG. 3) of the paper feed tray main body 21a.

  According to the above configuration, the paper feed roller 22a and the main body portion 23a of the pinch roller 23 sandwich the recording paper P, that is, the main body portion 23a of the pinch roller 23 passes through the recording paper P by the paper feed roller 22a. Since the storage portion 21b, which is a leaf spring member, bends in a pressed state, there is an error in the size and shape of the component parts of the printer 1, or there is an error when assembling the component parts. Also, the distance between the two pairs of the pinch roller 23 and the paper feed roller 22a can be made substantially equal. Therefore, the recording paper P can be pinched reliably in each pair. Accordingly, it is possible to prevent the recording paper P from being skewed when the recording paper P is fed, that is, during paper feeding. Further, since the leaf spring member is formed by molding the paper feed tray 21 into a specific shape, it is not necessary to newly provide an urging component, and cost can be reduced.

  In addition, this invention is not limited to the structure of the said embodiment, A various deformation | transformation is possible suitably in the range which does not change the meaning of invention. For example, the printer 1 may be configured to be able to form an image on the recording paper P by, for example, an electrophotographic method instead of the ink jet method. The printer 1 may be equipped with a scanner device.

1 is a perspective view of an image forming apparatus according to an embodiment of the present invention. (A) is a plan view cutaway view of the sheet feeding device of the above apparatus, (b) is an enlarged plan view of a broken line frame C portion of (a). D-D 'line sectional drawing of FIG.

Explanation of symbols

1 Printer (image forming device)
2 Feeder 20 Housing 21 Feeder tray 21a Feeder tray body 21b Storage part 21c Bearing part 22 Recording paper transport mechanism 22a Feeder roller 22b Rotating shaft 22c Arm (biasing means)
23 Pinch roller 23a Body portion 23b Shaft portion 3 Ink cartridge (image forming portion)
3a Recording head 4 Carriage (image forming unit)
5 Drive mechanism (image forming unit)
A Main scanning direction B Sub scanning direction P Recording paper

Claims (3)

A sheet is placed on the housing and the back of the housing so that a portion on which the recording paper is placed is inclined so as to face upward and forward, and the recording paper conveyed into the housing is loaded so as to lean on the housing. A paper feeding device having a paper tray and a recording paper transport mechanism for transporting a recording paper loaded in the paper feed tray into the housing;
A carriage having a recording head which is disposed inside the casing and discharges ink toward a lower recording sheet conveyed by the recording sheet conveying mechanism;
An image forming apparatus comprising: a driving mechanism that reciprocates the carriage in a main scanning direction substantially orthogonal to a recording paper conveyance direction;
The recording paper transport mechanism is
Two paper feed rollers for feeding the recording paper placed on the paper feed tray into the housing;
A rotating shaft disposed in parallel with the main scanning direction, with the two paper feed rollers spaced apart and axially supported;
An urging unit that supports both end portions of the rotating shaft, and urges the sheet feeding roller and the rotating shaft toward the sheet feeding tray;
A column-shaped main body provided on the paper feed tray side and composed of shafts projecting from both ends of the main body, and paired with each of the two paper feed rollers. The main body portion has two pinch rollers that sandwich the recording paper with the paper feed roller, and is arranged so that the direction is substantially parallel to the main scanning direction,
The paper feed tray is
A storage portion that is recessed in the attachment portion of the pinch roller in the paper feed tray and stores a part of the main body of the pinch roller;
A bearing portion with which the shaft portion of the pinch roller is engaged,
The storage portion is configured by a leaf spring member that urges the body portion of the pinch roller in the direction of the paper feed roller,
In a state where the paper feed roller and the pinch roller sandwich the recording paper, the leaf spring member bends and the distance between the two pairs of the paper feed roller and the pinch roller becomes substantially equal, so that recording is performed during paper feeding. An image forming apparatus configured to prevent skew of paper. A housing,
A paper feed tray that is disposed on the back of the housing so as to be inclined so that a portion on which the recording paper is placed faces upward and forward, and is loaded so that the recording paper conveyed inside the housing is stood ,
A recording paper transport mechanism for transporting the recording paper loaded in the paper feed tray into the housing;
In an image forming apparatus provided with an image forming unit that forms an image on recording paper conveyed in a predetermined direction,
The recording paper transport mechanism is
A plurality of paper feed rollers for feeding the recording paper placed on the paper feed tray into the housing;
A column-shaped main body portion provided on the paper feed tray side and a shaft portion projecting from both end portions of the main body portion, and is paired with each of the plurality of paper feed rollers. The main body has a plurality of pinch rollers that sandwich the recording paper with the paper feed roller, and is arranged so that the direction is substantially parallel to the main scanning direction,
The paper feed tray is formed integrally with the paper feed tray, and has a leaf spring member that urges the body portion of the pinch roller in the direction of the paper feed roller,
In a state where the paper feed roller and the pinch roller sandwich the recording paper, the leaf spring member bends, and the intervals between the paper feed roller and the pinch roller that form a plurality of pairs become substantially equal, and recording during paper feeding An image forming apparatus configured to prevent skew of paper.   The image forming apparatus according to claim 2, wherein the number of the paper feed rollers and the pinch rollers is two.

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