JP6486802B2 - Document conveying apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a document conveying device that conveys a document and an image forming apparatus including the document conveying device.

  An image forming apparatus such as a multifunction peripheral is provided with a document reading device. Further, the document reading device is usually used together with a document conveying device.

  The document conveying device separates and feeds documents one by one from a bundle of documents placed on the document tray, and conveys the document to the discharge tray via the image reading position. Further, the document conveying device performs a registration operation for preventing the document from being obliquely conveyed. For this reason, a registration roller is disposed upstream of the image reading position (upstream in the document conveying direction). Yes.

  In the registration operation, the leading edge of the conveyed document is abutted against the stopped registration roller, and further, the document is bent to cause the document to be bent so that the leading edge of the document is parallel to the rotation axis of the registration roller. . Thereafter, the rotation of the registration roller is started, and the document is conveyed to the image reading position.

  In recent document conveying apparatuses, the document conveying speed is also increased in order to improve job efficiency. However, when a document conveyed at high speed hits the registration roller, there is a problem that a collision sound at that time becomes loud. Patent Document 1 discloses a technique for reducing the document conveyance speed immediately before the registration roller in order to reduce the collision noise.

Japanese Patent Laid-Open No. 2004-210466

  In the above-mentioned Patent Document 1, the document transport speed is decreased immediately before the registration roller, but a specific selection of the document transport speed at this time is not disclosed. Therefore, there is a problem that the conveyance speed control becomes complicated by having a plurality of document conveyance speeds in one type of document conveyance mode.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a document conveying device that can reduce a collision sound when a document hits a registration roller and can simplify speed control of a document conveying speed. To do.

  In order to solve the above-described problems, the present invention provides a document transport apparatus having a high speed mode and a low speed mode, and a document transport speed by a paper feed roller until a leading edge of a transported document hits a registration roller. However, in the low-speed mode, it is the first speed, and in the high-speed mode, after the paper feeding is started at a second speed larger than the first speed, the leading edge of the conveyed document is the registration roller. Before it hits, the speed is reduced to the first speed.

  According to the above configuration, in the high-speed mode, after the document feeding and conveyance is started at the second speed, the document conveyance speed is reduced to the first speed immediately before the leading edge of the document hits the registration roller. The first speed is also the conveyance speed of the paper feed roller in the low speed mode. Therefore, in the document conveying device, it is not necessary to prepare other conveying speeds other than the second speed corresponding to the high speed mode and the first speed corresponding to the low speed mode as the conveying speed of the paper feed roller. Therefore, it is possible to simplify the speed control of the paper feed roller while preventing a collision sound when the document hits the registration roller.

  In the high speed mode, the original conveying apparatus may be configured such that the original conveying speed of the registration roller is higher than the first speed.

  According to the above configuration, the document conveyance speed by the registration roller is increased with respect to the document conveyance speed immediately before the document hits the registration roller, and the job efficiency can be increased.

  The document conveying device may be configured to maintain the document conveying speed of the registration roller until the trailing edge of the document passes the registration roller.

  In order to solve the above-described problems, the present invention is an image forming apparatus including the document conveying device described above.

  According to the above configuration, when the scanner function, the copying function, the facsimile function, or the like in the image forming apparatus is used, it is possible to prevent a collision sound when the document hits the registration roller in the document conveying device, and the speed of the sheet feeding roller. Control can also be simplified.

  In the document conveying device and the image forming apparatus according to the present invention, the document conveying device has a high-speed mode and a low-speed mode. In the high-speed mode, the document leading edge is registered after the document feeding / conveying is started at the second speed. Immediately before hitting the roller, the document transport speed is reduced to the first speed corresponding to the low speed mode. For this reason, there is an effect that the speed control of the paper feed roller can be simplified while preventing a collision sound when the document hits the registration roller.

1 is a cross-sectional view illustrating a schematic configuration of a document conveying device according to Embodiment 1. FIG. FIG. 4 is a diagram illustrating a driving mechanism of each roller in the document conveying device. 6 is a timing chart illustrating conveyance speed control in a low-speed mode of the document conveyance device. 6 is a timing chart illustrating conveyance speed control in a high-speed mode of the document conveyance device. 5 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to Embodiment 2. FIG.

[Embodiment 1]
Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view illustrating the configuration of the document conveying device 10 and the image reading device 30 according to the first embodiment. The document conveying device 10 is pivotally supported on the inner side of the image reading device 30 by a hinge (not shown) and opened and closed by moving the front portion up and down. When the document feeder 10 is opened, the platen glass 31 of the image reading device 30 is opened, and the document is placed on the platen glass 31.

  The image reading device 30 includes a platen glass 31, a first scanning unit 32, a second scanning unit 33, an imaging lens 34, a CCD (Charge Coupled Device) 35, and the like. The first scanning unit 32 exposes the original on the platen glass 31 with a light source while moving at a constant speed V in the sub-scanning direction according to the original size, and guides the reflected light to the second scanning unit 33. Thus, the image on the surface of the document is scanned in the sub-scanning direction. The second scanning unit 33 guides reflected light from the document to the imaging lens 34 while moving at a speed V / 2 following the first scanning unit 32. The imaging lens 34 condenses the reflected light from the document on the CCD 35 and forms an image on the surface of the document on the CCD 35. The CCD 35 repeatedly scans the document image in the main scanning direction, and outputs an analog image signal of one main scanning line each time.

  Further, the image reading device 30 can read not only a stationary document but also an image on the surface of the document being conveyed by the document conveying device 10. In this case, the first scanning unit 32 is moved below the original reading glass 36, and the second scanning unit 33 is positioned according to the position of the first scanning unit 32. Start conveyance.

  In the document conveying device 10, the pickup roller 11 is pressed against the document on the document tray 12 and rotated, the document is pulled out, the document is fed to the document conveying path 14 by the paper feed roller 13, and the leading edge of the document is temporarily stopped. Then, the registration rollers 15a and 15b start to convey the original, the conveyance rollers 16a and 16b convey the original, and the original is read with the original reading glass 36. The original is passed between the reading guide plates 17 and conveyed to the paper discharge tray 20 through the reversing rollers 18a and 18b and the paper discharge rollers 19a and 19b.

  When the original is conveyed, the original surface is illuminated by the light source of the first scanning unit 32 via the original reading glass 36, and the reflected light from the original surface is sent to the imaging lens 34 by the first and second scanning units 32 and 33. Then, the reflected light from the document surface is condensed on the CCD 35 by the imaging lens 34, and the image on the document surface is imaged on the CCD 35, thereby reading the image on the document surface.

  When reading the back side of the document, each reversing roller 18a, 18b and each discharge roller 19a is in the middle of discharging the document to the discharge tray 20 through each reversing roller 18a, 18b and each discharge roller 19a, 19b. , 19b are temporarily stopped, and then the reversing rollers 18a, 18b and the paper discharge rollers 19a, 19b are rotated in the reverse direction, and the original is guided to the registration rollers 15a, 15b through the reverse conveying path 21, thereby The front and back sides are reversed, and the image on the back side of the document is read in the same manner as the image on the front side of the document, and the reversing rollers 18a and 18b and the paper discharge rollers 19a and 19b are rotated in the forward direction. And it conveys to each discharge roller 19a, 19b. The reversing rollers 18a and 18b and the discharge rollers 19a and 19b are set in order to match the order of the documents on the document tray 12 and the orientation of the front and back with the order of the documents on the delivery tray 20 and the orientation of the front and back. The document is rotated again in the reverse direction, and the original is guided again to the registration rollers 15a and 15b through the reverse conveyance path 21, and the reverse rollers 18a and 18b and the discharge rollers 19a and 19b are moved in the forward direction without reading the original. The document is rotated and discharged to the discharge tray 20.

  The original image read by the CCD 35 is output as an analog image signal from the CCD 35, and the analog image signal is A / D converted into a digital image signal (image data).

  Next, the driving mechanism of each roller in the document feeder 10 will be described with reference to FIG. The document conveying device 10 has two drive motors 22 and 23. The drive motor 22 rotates the pickup roller 11 and the paper feed roller 13. The registration rollers 15 a, the transport rollers 16 a, the reversing rollers 18 a, and the paper discharge rollers 19 a are drive rollers, and these rollers are driven by a drive motor 23. The registration roller 15b, each conveyance roller 16b, the reverse roller 18b, and the paper discharge roller 19b are driven rollers. The registration roller 15a is connected to the drive motor 23 via the clutch 24, and connection / disconnection with the drive motor is switched by turning on / off the clutch 24. The drive motors 22 and 23 and the clutch 24 are controlled by a control unit (not shown) included in the document feeder 10.

  The document conveying apparatus 10 according to the first embodiment has a low speed mode and a high speed mode as two document conveying modes having different document conveying speeds. The conveyance speed control in the low speed mode and the high speed mode will be described with reference to FIGS.

  FIG. 3 is a timing chart showing conveyance speed control in the low speed mode. (A) is a conveyance speed by the paper feed roller 13, (b) is a conveyance speed by each of the conveyance rollers 16a and 16b, (c) is on / off of the clutch 24, (d) is a conveyance speed by the registration rollers 15a and 15b, (E) indicates the conveyance speed of the leading edge of the document.

  At the document feed start time t0, the paper feed roller 13 is driven at a transport speed VL1 (first speed) corresponding to the low speed mode, and the transport rollers 16a and 16b are transport speed VL2 corresponding to the low speed mode. It is driven by. Further, at the document feed start time t0, the clutch 24 is turned off, and the conveying speed of the registration rollers 15a and 15b is 0 (stopped). The original is started to be fed by the feed roller 13, and the leading edge speed at this time is equal to the feed speed VL 1 of the feed roller 13.

  Next, time t1 indicates the timing at which the leading edge of the document is detected by the document detection sensor 25 (see FIG. 2). The document detection sensor 25 is disposed upstream of the registration rollers 15a and 15b in the document transport direction as shown in FIG.

  When a predetermined time elapses from time t1 and time t2 is reached, the leading edge of the document hits the registration rollers 15a and 15b, and the leading edge speed of the document becomes zero. From time t2 to time t3, the leading edge of the document abuts against the registration rollers 15a and 15b and stops, but the conveyance by the paper feed roller 13 continues. For this reason, the document is bent between the registration rollers 15a and 15b and the paper feed roller 13, and the leading edge of the document is made parallel to the rotation shaft of the registration rollers 15a and 15b, thereby preventing the subsequent oblique conveyance.

  At time t3, the clutch 24 is turned on, and the conveyance speed of the registration rollers 15a and 15b becomes the conveyance speed VL2 similarly to the conveyance rollers 16a and 16b. That is, the document front end speed becomes the transport speed VL2 at time t3. When the time t3 has passed, the conveyance of the paper feed roller 13 is stopped, and the conveyance speed VL2 of the registration rollers 15a and 15b is maintained until the trailing edge of the document passes the registration rollers 15a and 15b. The trailing edge of the document that has passed through the registration rollers 15a and 15b is detected by the document detection sensor 26 (see FIG. 2). At the time of this detection, the clutch is turned off and the registration rollers 15a and 15b are stopped.

  FIG. 4 is a timing chart showing conveyance speed control in the high speed mode. (A) is a conveyance speed by the paper feed roller 13, (b) is a conveyance speed by each of the conveyance rollers 16a and 16b, (c) is on / off of the clutch 24, (d) is a conveyance speed by the registration rollers 15a and 15b, (E) indicates the conveyance speed of the leading edge of the document.

  At the document feed start time t0, the paper feed roller 13 is driven at a transport speed VH1 (second speed) corresponding to the high speed mode, and the transport rollers 16a and 16b are transport speed VH2 corresponding to the high speed mode. It is driven by. Each of the conveyance speeds VH1 and VH2 in the high speed mode can be set to, for example, twice the conveyance speeds VL1 and VL2 in the low speed mode. Further, at the document feed start time t0, the clutch 24 is turned off, and the conveying speed of the registration rollers 15a and 15b is 0 (stopped). The original is started to be fed by the feed roller 13, and the leading edge speed at this time is equal to the feed speed VH 1 of the feed roller 13.

  In the high-speed mode, the feeding of the document is started at the transport speed VH1, but there is a problem that when the document hits the registration rollers 15a and 15b at this speed, the collision noise increases. For this reason, in the high speed mode, when the leading edge of the document is detected by the document detection sensor 25 at time t1, speed control is performed to reduce the conveyance speed of the paper feed roller 13. Specifically, before reaching the time t2 when the leading edge of the document hits the registration rollers 15a and 15b, the conveyance speed of the paper feed roller 13 is reduced to the conveyance speed VL1 corresponding to the low speed mode.

  At time t2, the leading edge of the document hits the registration rollers 15a and 15b, and the document leading edge speed becomes zero. At this time, since the conveyance speed of the paper feed roller 13 is reduced to the conveyance speed VL1, it is possible to prevent a collision sound when the document hits the registration rollers 15a and 15b.

  At time t3, the clutch 24 is turned on, and the conveyance speed of the registration rollers 15a and 15b becomes the conveyance speed VH2 similarly to the conveyance rollers 16a and 16b. That is, the document front end speed becomes the transport speed VH2 at time t3. Further, after time t3, the conveyance of the paper feed roller 13 is stopped.

  Here, the conveyance speed VH2 is higher than the conveyance speed VL1. That is, the document conveyance speed by the registration rollers 15a and 15b is increased with respect to the document conveyance speed immediately before the document hits the registration rollers 15a and 15b, and the job efficiency can be increased. The conveyance speed VH2 of the registration rollers 15a and 15b is maintained until the document is conveyed to the reading position.

  As described above, the document conveying apparatus 10 according to the first embodiment has two conveyance modes, the high-speed mode and the low-speed mode. In the high-speed mode, the document feeding conveyance starts at the conveyance speed VH1. Then, immediately before the leading edge of the document hits the registration rollers 15a and 15b, the document transport speed is reduced to the transport speed VL1 (<VH1). The conveyance speed VL1 is also the conveyance speed of the paper feed roller 13 in the low speed mode.

  In the document conveying apparatus 10 according to the first embodiment, it is necessary to prepare other conveying speeds other than the conveying speed VH1 corresponding to the high speed mode and the conveying speed VL1 corresponding to the low speed mode as the conveying speed of the paper feed roller 13. There is no. Therefore, it is possible to simplify the speed control of the paper feed roller 13 while preventing a collision sound when the document hits the registration rollers 15a and 15b.

[Embodiment 2]
Hereinafter, Embodiment 2 of the present invention will be described in detail with reference to the drawings.

  FIG. 5 is a cross-sectional view showing image forming apparatus 100 according to the second embodiment. The image forming apparatus 100 is a so-called multifunction machine having a scanner function, a copying function, a printer function, a facsimile function, and the like. The image forming apparatus 100 transmits an image of a document read by the image reading device 30 to the outside, or reads the read document. Or an image received from the outside is recorded on a recording sheet in color or single color.

  The image forming apparatus 100 includes an optical scanning device 101, a developing device 102, a photosensitive drum 103, a drum cleaning device 104, a charger 105, and an intermediate transfer belt device 106 in order to print an image on recording paper by a known electrophotographic technique. A fixing device 107, a paper feed tray 108, a paper discharge tray 109, and the like.

  The image data handled in the image forming apparatus 100 uses data corresponding to a color image using each color of black (K), cyan (C), magenta (M), yellow (Y), or a single color (for example, black). This is in accordance with the monochrome image. For this reason, four each of the developing device 102, the photosensitive drum 103, the drum cleaning device 104, and the charger 105 are provided so as to form four types of toner images corresponding to the respective colors, and black, cyan, Four image stations Pa, Pb, Pc, and Pd are configured in association with magenta and yellow.

  In the image forming apparatus 100 according to the second embodiment, the document conveying device 10 is disposed above the image reading device 30. The image reading device 30 can read an image on the surface of the document conveyed by the document conveying device 10. The image forming apparatus 100 according to the second embodiment applies the document conveying device 10 according to the first embodiment as the document conveying device 10.

  As a result, in the image forming apparatus 100 according to the second embodiment, when the scanner function, the copying function, the facsimile function, or the like is used, it is possible to prevent a collision sound when the document hits the registration roller in the document conveying device 10. .

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Document conveying apparatus 13 Paper feed roller 15a, 15b Registration roller 16a, 16b Transport roller 18a, 18b Reverse roller 19a, 19b Paper discharge roller 22, 23 Drive motor 24 Clutch 25, 26 Document detection sensor 30 Image reading apparatus 100 Image forming apparatus VL1 Feeding roller conveyance speed according to low speed mode (first speed)
VH1 Feed roller conveyance speed according to high-speed mode (second speed)
VL2 Registration roller conveyance speed according to low speed mode VH2 Registration roller conveyance speed according to high speed mode

Claims (4)

An original conveying apparatus having a high speed mode and a low speed mode,
The document transport speed by the paper feed roller until the leading edge of the transported document hits the registration roller is
In the low speed mode, the first speed,
In the high-speed mode, after feeding is started at a second speed that is higher than the first speed, the first speed is decelerated before the leading edge of the conveyed document hits the registration roller. An original conveying apparatus characterized by the above. The document conveying device according to claim 1,
In the high-speed mode, the document transporting speed of the registration roller is higher than the first speed. The document conveying device according to claim 1 or 2,
An original conveying apparatus, wherein the original conveying speed of the registration roller is maintained until a rear end of the original passes through the registration roller.   An image forming apparatus comprising the document conveying device according to claim 1.

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