Patent Application
20160257517
1. Field of the Invention
The present invention relates to a reading apparatus and a recording apparatus.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. 2005-8283 discusses an apparatus including an elevating unit that raises and lowers a sheet feeding tray, including a gear, a rack, and a motor, and an elevation control unit that controls the rise and fall of the sheet feeding tray using an optical sensor. According to the apparatus discussed in Japanese Patent Application Laid-Open No. 2005-8283, a stacking capacity on a sheet discharge tray can be increased as the number of documents on the sheet feeding tray decreases. Therefore, the apparatus can feed a large amount of documents while the apparatus is reduced in space.
However, in the apparatus discussed in Japanese Patent Application Laid-Open No. 2005-8283, the height of the stacked documents is detected using the optical sensor, and the rise and fall of the sheet feeding tray is controlled based on a detection result. Therefore, the optical sensor may react only if the thickness of the stacked documents is changed to some extent, so that the decrease in the number of the documents on the sheet feeding tray and the rise of the sheet feeding tray and a sheet discharge unit (sheet discharge roller) are not interlocked with each other. Accordingly, the height of the sheet discharge unit needs to be determined while allowing for a period elapsed until the optical sensor detects the change in the thickness of the stacked documents, which has been disadvantageous to reduce the height of the apparatus.
Further, even if a sheet feeding and discharge unit is reduced in space, use of mechanism components such as a gear and a rack for an elevating device results in a complicated structure. Therefore, it may be difficult to reduce the size of the apparatus. To provide the elevating device, a control error of the elevating device and a clearance of an operation unit need to be considered, which has been disadvantageous to reduce the height of the apparatus.
The present invention is directed to a reading apparatus and a recording apparatus the respective heights of which can be reduced without reducing the number of documents that can be fed, with a simple configuration.
According to an aspect of the present invention, a reading apparatus includes a reading unit configured to read a document, a feeding tray on which the document to be read by the reading unit is stacked, a feeding roller that feeds the document from the feeding tray to a position where the document is read by the reading unit, a feeding pressure plate that presses the document against the feeding roller so that the document is pinched between the feeding roller and the feeding pressure plate, and a discharge roller that discharges the document read by the reading unit to underneath the feeding pressure plate, wherein a position of the discharge roller moves depending on a number of documents pinched between the feeding roller and the feeding pressure plate.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
An exemplary embodiment of the present invention will be specifically described below with reference to the drawings.
The present invention is applicable to not only a reading apparatus (document reading apparatus) that includes an automatic document feeder (ADF) and reads a document using an image sensor (reading unit) but also a recording apparatus having a recording function of recording an image together with a reading function. Examples of the recording apparatus include a multifunction apparatus (multifunction peripheral) also having other functions such as a facsimile (FAX) function in addition to a printing function (recording function). Further, the present invention is also applicable to a recording apparatus having a recording function of recording an image on a recording medium instead of a reading function. In that case, not a document but a recording medium on which an image is to be recorded is stacked on a feeding tray, a recording unit is provided instead of a reading unit in a conveyance path, and the image is recorded by the recording unit on the conveyed recording medium.
A reading apparatus according to the exemplary embodiment of the present invention will be specifically described.
An operation panel 13 serving as a user interface having an indicator and an input unit arranged on a front side of the operation panel 13 is provided on an upper surface of the ADF 3. A main part of the ADF 3 is a feeding unit 2 that feeds documents one by one to a reading position of the scanner. The feeding unit 2 and a discharge tray 12 are provided on a base 3a which is a housing of the ADF 3. The ADF 3 is attached to the document platen unit 14 to be operable and closable with respect to the document platen unit 14 with the hinge 4 including a hinge 4a and a hinge 4b provided at two positions on a back side of the document platen unit 14 in the reading apparatus 1. A user manually performs an opening and closing operation on a front side of the reading apparatus 1.
Each of the two hinges 4a and 4b has a rotation axis and a damper mechanism. Axial directions of the two rotational axes are the same direction (X-direction). One component of each of the hinges 4a and 4b is fixed to the base 3a, and the other component of each of the hinges 4a and 4b is fixed to the document platen unit 14. More specifically, the other components of the hinges 4a and 4b are respectively inserted to be slidable up and down into recessed portions 10a and 10b formed in a base 24 (see
A hole 5 through which an electric cable is to be passed is provided on the base 3a of the ADF 3 and an upper surface of the document platen unit 14, between the hinges 4a and 4b. The electric cable including a flexible flat cable (FFC) connected to electric components such as a motor and an encoder sensor provided in the feeding unit 2 in the ADF 3 is wired via the hole 5, and is connected to a main printed circuit board (PCB) (control unit) provided inside the document platen unit 14. In this manner, the electric cable is wired without passing near a gear train 9d, and is connected to the control unit. Therefore, even if a position of the electric cable is shifted due to a shock and a vibration, the electric cable does not contact the gear train 9d.
As illustrated in
When an operation for reading a document is performed with the flatbed scanner (FBS), the user first opens the ADF 3, places a sheet document or a book document on the reading surface 16, and then closes the ADF 3 to fix the document. While the motor 22 is driven to move the carriage 21 so that the line sensor unit 23 scans and moves, the line sensor unit 23 reads the document.
When an operation for reading a document is performed with the sheet-through scanner, the feeding unit 2 in the ADF 3 feeds documents one by one. The line sensor unit 23, which is at rest at a home position, reads the documents that pass on the reading window 15.
The feeding unit 2 in the ADF 3 will be described below with reference to the drawings.
The feeding unit 2 which is the main part of the ADF 3 roughly includes a feeding tray 6, a roller group 7 for conveying a document, a motor 9a, the transmission gear train 9d for transmitting the rotation of a rotating shaft of the motor 9a to the roller group 7, and an encoder unit that detects rotation information about the motor 9a. The motor 9a is a DC motor. The encoder unit includes an encoder sensor 9b and a code wheel 9c. The driving unit 9 includes the motor 9a, the encoder sensor 9b, the code wheel 9c, and the transmission gear train 9d. At least a part of the transmission gear train 9d, the motor 9a, and the code wheel 9c are arranged between the hinges 4a and 4b provided at two positions in the axial direction (X-direction) of the rotation axis of the hinge 4.
The feeding tray 6 on which a plurality of documents can be stacked is provided in an upper part of the feeding unit 2. The feeding tray 6 is provided with a sensor that detects that the documents are set. A feeding pressure plate 61 is provided at an end of the feeding tray 6 in a document conveyance direction. The feeding pressure plate 61 is rotatably supported to swing with a position on the downstream side of the feeding tray 6 in the document conveyance direction as a rotation center of the feeding pressure plate 61. When a feeding operation is started, a cam member (not illustrated) is unlocked, and a compression spring 62 (an urging unit) applies feeding pressure to the feeding pressure plate 61 (urges the feeding pressure plate 61). Such a configuration enables the height of the feeding pressure plate 61 to change depending on the number of the stacked documents. Details will be described below. After a reading operation is completed, when the reading operation is started again, the feeding pressure plate 61 moves to a position (home position) where the document can be set again by the function of the cam member (not illustrated).
The roller group 7 includes a plurality of rollers for conveying the documents stacked on the feeding tray 6 one by one. A path through which the document is conveyed is folded in a U-turn shape halfway. The roller group 7 mainly includes four rollers, i.e., a pickup roller 7a (a feeding roller), a separation roller 7b, a conveyance roller 7c, and a discharge roller 7d. The documents stacked on the feeding tray 6 are pushed up under the feeding pressure by the feeding pressure plate 61, and are pressed against the pickup roller 7a. At this time, the documents remains pinched between the pickup roller 7a and the feeding pressure roller 61. The pickup roller 7a can pick up the uppermost one of the stacked documents by rotating in this state. The separation roller 7b can reliably separate, when the plurality of documents has been picked up while being overlaid, the overlaid documents one by one. The conveyance roller 7c is provided halfway in the path 8. The conveyance roller 7c conveys, even when reading operations of both a surface (first surface) and a rear surface (second surface) of the document are performed, the document toward a position where the line sensor reads the document. The discharge roller 7d discharges the document, which has been read, to the discharge tray 12 provided underneath the feeding pressure plate 61.
The discharge roller 7d is attached to the bottom of the feeding pressure plate 61. Therefore, an operation of the discharge roller 7d is interlocked with the feeding operation of the feeding pressure plate 61. As the feeding operation progresses, the feeding pressure plate 61 rises, and accordingly the discharge roller 7d also rises. Details will be described below. A pinch roller (driven roller), which is driven by the discharge roller 7d, is also attached to the feeding pressure plate 61, like the discharge roller 7d. The pinch roller is driven to rotate by the discharge roller 7d at a position opposing the discharge roller 7d, to convey the document with the document pinched between the discharge roller 7d and the pinch roller. The pinch roller applies a predetermined pinching pressure to the discharge roller 7d regardless of a displacement of the discharge roller 7d. In the present exemplary embodiment, the pinch roller, which is driven by the discharge roller 7d, is attached to the feeding pressure plate 61, like in the discharge roller 7d, to keep the pinching pressure applied to the discharge roller 7d constant. However, the present invention is not limited to this. The pinch roller may be held in another frame to follow the rise of the discharge roller 7d while ensuring the pinching pressure required to pinch and convey the document.
The motor 9a serving as a driving source and the transmission gear train 9d for decelerating the rotation of the motor 9a and transmitting the decelerated rotation to each of the rollers of the roller group 7 are arranged on the side (back side) of the hinge 4 in the feeding unit 2. The motor 9a has a body in a cylindrical vertically long shape in which the length in the axial direction (X-direction) of the rotating shaft (output shaft) is larger than that in a radial direction (a Y-axis direction and a Z-direction). The rotating shaft of the motor 9a protrudes longways with respect to the body of the motor 9a on both sides (head and tail sides) of the rotating shaft. The rotating shaft of the motor 9a is substantially parallel to the respective rotation axes of the hinges 4a and 4b. A rotation axis of each of the rollers constituting the roller group 7 is arranged so that an axial direction of the rotating shaft is the Y-direction. The direction is perpendicular to the axial direction of the rotating shaft of the motor 9a. The rotation axis of each of the rollers and the rotating shaft of the motor 9a may not necessarily perpendicular to each other.
A worm gear 9e, which is a part of the transmission gear train 9d, is attached to an end on the head side (referred to as a first end) of the rotating shaft of the motor 9a on the side of the transmission gear train 9d. The transmission gear train 9d includes a plurality of gears including a gear 9f that meshes with the worm gear 9e. The rotation of the motor 9a is transmitted to each of the gears in the transmission gear train 9d via the worm gear 9e. The transmission gear train 9d includes gears respectively attached to ends of the rotation axes of the pickup roller 7a, the separation roller 7b, the conveyance roller 7c, and the discharge roller 7d, and a plurality of idler gears for driving transmission among those gears. When viewed from above (in the Z-direction), the transmission gear train 9d is arranged substantially along a direction in which the rotating shaft of the motor 9a extends. When viewed from the side (in the Y-direction), the gear train 9d is also arranged substantially along the direction in which the rotating shaft of the motor 9a extends. The rotating shaft of the motor 9a may have an inclination to a direction in which the gear train 9d is formed.
To transmit a driving force to the discharge roller 7d, a gear 9g is arranged at a rotation center around which the feeding pressure plate 61 swings. The driving force is transmitted to a gear 9j attached to an end of the discharge roller 7d via gears 9h and 9j from the gear 9g, to rotate the discharge roller 7d. The discharge roller 7d is attached to the bottom of the feeding pressure plate 61. Even when the discharge roller 7d, together with the feeding pressure plate 61, swings, therefore, the driving force can be accurately transmitted to the discharge roller 7d without being accompanied by a change between gear shafts. While the driving force is transmitted by the gears from the rotation center of the feeding pressure plate 61 to the discharge roller 7d in the present exemplary embodiment, the present invention is not limited to this. The driving force may be transmitted using a belt and a pulley in combination.
While the feeding pressure plate 61 has the rotation center and swings in the present exemplary embodiment, the feeding pressure plate 61 may move up and down in a normal direction of a document stacking surface. In the case, when the gear 9h includes a pendulum gear, the change between the gear shafts can be coped with. If the driving force is transmitted using the belt, the change between the gear shafts can be coped with by arranging a tensioner at an intermediate point of the belt.
On the other hand, the code wheel 9c in the encoder unit for detecting a rotational state (an amount of rotation and a rotation speed) of the motor 9a is attached to an end on the tail side (referred to as a second end) of the rotating shaft of the motor 9a on the opposite side of the side of the worm gear 9e. Further, the code wheel 9c is provided with an encoder sensor 9b having a photointerrupter for optically detecting a slit pattern formed in a cylindrical shape.
Thus, the worm gear 9e constituting a part of the transmission gear train 9d is attached to the end (first end) of the rotating shaft of the motor 9a, and the code wheel 9c is attached to the other end (second end) of the rotating shaft of the motor 9a. The encoder sensor 9b is also arranged at the second end. Thus, the code wheel 9c, the motor 9a, and the gears constituting the transmission gear train 9d substantially line up. When the code wheel 9c, the motor 9a, and the gears are thus arranged, a space is effectively used, to miniaturize the apparatus.
As the motor 9a rotates, the code wheel 9c arranged coaxially with the rotating shaft of the motor 9a also rotates. The encoder sensor 9b outputs a pulse signal as the slit pattern formed in the code wheel 9c passes therethrough. When the number of pulses is counted, the rotational state (the amount of rotation and the rotation speed) of the motor 9a can be detected. The control unit controls the rotation of the motor 9a so that document feeding is performed at a predetermined speed or by a predetermined amount in response to a detection result.
In the document reading apparatus configured as described above, the document is read in a pixel unit. The “pixel” is a virtual pixel obtained by dividing a longitudinal direction of a document surface (a movement direction of the document) and a transverse direction thereof (a direction in which elements included in the line sensor 202 are arranged) into pixels at a predetermined pitch. The size of one pixel in the transverse direction matches the size of one of the elements included in the line sensor 202. The size of one pixel in the longitudinal direction is determined by a speed at which the document is moved and a timing at which the document is read by the line sensor 202. If reading resolution is 600 dpi, for example, one pixel has a length of 1/600 inches.
In the document reading apparatus according to the exemplary embodiment of the present invention, an operation performed when a document is read with the sheet-through scanner using the ADF 3.
The user first sets one document or a plurality of documents on the feeding tray 6, and presses a scan start button provided on the operation panel 13. The control unit performs control to rotate the motor 9a when the sensor detects that the document is set in the feeding tray 6. As the motor 9a rotates, the gears included in the transmission gear train 9d, i.e., the worm gear 9e to the gear 9f and the subsequent gear train rotate. Thus, the pickup roller 7a, the separation roller 7b, the conveyance roller 7c, and the discharge roller 7d constituting the roller group 7 concurrently rotate.
Then, the feeding pressure plate 61 rises, and the uppermost document is pressed against the pickup roller 7a. The document remains pinched between the pickup roller 7a and the feeding pickup roller 61. In the state, the pickup roller 7a rotates. Therefore, the uppermost document is pickup up. The documents picked up are reliably separated one by one with a frictional force between the separation roller 7b and a separation pad opposing the separation roller 7b. The conveyance roller 7c conveys the documents along the path 8 at a predetermined speed. The document is scanned by the line sensor unit 23 while being conveyed at a predetermined speed with a reading surface (first surface) of the document directed toward the reading window 15, and is read. The discharge roller 7d discharges the read document onto the discharge tray 12.
A configuration in which as the number of documents pinched between the pickup roller 7a and the feeding pressure plate 61 decreases, the discharge roller 7d moves in a height direction and a discharge space (the number of documents that can be stacked) on the discharge tray 12 increases, which characterizes the present invention, will be specifically described.
When the document feeding progresses, the feeding pressure plate 61 rises, as illustrated in
When a reading operation for all the documents is completed, the feeding pressure plate 61 finally rises to a maximum extent, to remain pressed against the pickup roller 7a, as illustrated in
As described above, according to the present invention, there can be provided a reading apparatus and a recording apparatus the respective heights of which can be reduced without reducing the number of documents that can be fed, with a simple configuration.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2015-044057, filed Mar. 5, 2015, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-044057 | Mar 2015 | JP | national |
