JP5330726B2 - Document feeder and image forming apparatus - Google Patents

Description

  The present invention relates to a document feeding device and an image forming apparatus, and more particularly, to a document feeding device capable of changing a speed at which a document is conveyed, and an image forming apparatus including such a document feeding device.

  The image forming apparatus is provided with a document feeder such as an ADF (Auto Document Feeder) that automatically conveys a document set on a document tray. The image forming apparatus forms an image from the original conveyed to the reading position of the image reading unit by the original feeding device.

  When a document is transported by the document feeder, slippage of the transport roller or the like causes a delay in transporting the document. As a result, the time for ending the conveyance of the document is delayed as compared with the case where no slip occurs, and there is a possibility that the processing performance of the product standard may not be achieved.

In such a case, Japanese Patent Application Laid-Open No. 2001-3284 (Patent Document 1) discloses a technique for changing the speed at which a document is conveyed faster. According to Patent Document 1, if a delay occurs in the conveyance of the nth original and the nth original and the (n + 1) th original are separated, the delay is recovered by conveying the n + 1th original at a high speed. I am going to do that.
JP 2001-3284 (paragraph numbers 0041 to 0071, 0085 to 0092)

  According to Patent Document 1, the speed at which a document is conveyed is constant throughout the document feeder. Therefore, when transporting at high speed, the transport speed at the reading position of the image reading unit is also high.

  Then, when reading an image of a document, it must be read at high speed. In this case, the reading accuracy of the original image is deteriorated due to a decrease in the amount of light applied to the original. As a result, the image quality of the image formed in the image forming apparatus is degraded.

  However, taking into account delays in document transportation such as slipping, if the document transportation speed is slowed with a sufficient document transportation speed, the product processing performance will deteriorate.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a document feeder capable of shortening the time taken to transport a document and appropriately reading a document image.

  Another object of the present invention is to provide an image forming apparatus capable of shortening the time taken to convey a document and forming a good image.

The document feeder according to the present invention includes a document tray for setting a document to be transported, a first transport unit that transports a document to a predetermined position from the document tray to a reading position for reading the document, and reads the document from the document tray. A detection unit that is provided at a predetermined position up to the reading position and detects the leading edge of the document conveyed by the first conveyance unit, a second conveyance unit that conveys the document after the predetermined position, and a first conveyance A changing means for changing the speed at which the document is conveyed by the means, and a time from when the driving of the first conveying means is started until the leading edge of the document set on the document tray is detected by the detecting means. Determining means for determining whether or not the time when the original is conveyed is later than a predetermined time, and the determining means calculates a delay amount when the original is conveyed by the first conveying means. The changing means includes a calculating means, and when the judging means judges that the time is later than the predetermined time, the changing means increases the speed at which the first conveying means conveys the document, and based on the delay amount, the first conveying means Thus, the speed at the time of conveying a plurality of documents is uniformly increased so as to be a predetermined speed.

  In another aspect of the present invention, the document feeder includes the document feeder described above and an image forming unit that forms an image from the document conveyed by the document feeder.

  The document feeder according to the present invention changes the speed at which the document is conveyed to a predetermined location from the document tray to the reading position. As a result, even when a document conveyance delay occurs, the document conveyance speed can be increased to a predetermined position from the document tray to the reading position, and the document conveyance time can be shortened. . At this time, since the reading position can be set to a speed different from the speed at which the original is conveyed from the original tray to a predetermined location, the original image can be appropriately read. As a result, it is possible to shorten the time required for transporting the document and appropriately read the image of the document.

  In addition, since the image forming apparatus according to the present invention includes such a document feeding device, the time required for transporting the document is shortened, the image of the document is appropriately read, and based on the read image of the document, An image can be formed.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a digital multifunction peripheral 10 when an image forming apparatus including a document feeder according to an embodiment of the present invention is applied to the digital multifunction peripheral 10. Referring to FIG. 1, a digital multifunction peripheral 10 displays a control unit 11 that controls the entire digital multifunction peripheral 10, a DRAM 12 for writing and reading image data and the like, and information that the digital multifunction peripheral 10 has. An operation unit 13 that includes a display screen and serves as an interface with a user in the digital multifunction peripheral 10; a document feeder 14 that includes an image reading unit 15 that conveys a document and reads the conveyed document with a scanner at a reading position; An image forming unit 16 that forms an image from a document read by the image reading unit 15 and outputs the image to a sheet, a hard disk 17 that stores image data and the like, a FAX communication unit 18 connected to the public line 20, and a network A network IF (interface) unit 19 for connecting to the network 21 is provided.

  The digital multifunction peripheral 10 operates as a copying machine by forming an image in the image forming unit 16 via the DRAM 12 using the image data of the original read by the image reading unit 15. Further, the digital multifunction peripheral 10 forms an image in the image forming unit 16 via the DRAM 12 using the image data transmitted from the personal computer 22 connected to the network 21 through the network IF unit 19, thereby serving as a printer. Operate. Further, the digital multifunction peripheral 10 forms an image in the image forming unit 16 through the DRAM 12 using the image data transmitted from the public line 20 through the FAX communication unit 18, and also by the image reading unit 15. The image data of the read original is transmitted to the public line 20 through the FAX communication unit 18 to operate as a facsimile machine. That is, the digital multi-function peripheral 10 has a plurality of functions such as a copying (copying) function, a printer function, and a FAX function regarding image processing. Further, each function has functions that can be set in more detail.

  In FIG. 1, thick arrows indicate the flow of image data, and thin arrows indicate the flow of control signals or control data.

  The control unit 11 compresses and writes the image data of the original document supplied from the image reading unit 15 to the DRAM 12, reads the data written to the DRAM 12, decompresses and decodes the data, and outputs it by the image forming unit 16.

  FIG. 2 is a diagram showing details of the document feeder 14. A dotted arrow in FIG. 2 indicates a document transport direction. 1 to 2, the document feeder 14 feeds a document tray 25 on which a document to be conveyed is set and a document set on the document tray 25 one by one to the document to a predetermined position. A paper feed roller 26 that transports, a transport motor 27 that controls the rotation of the paper feed roller 26, a timing sensor 29 that detects the leading edge of the document transported by the paper feed roller 26, and a predetermined location by the paper feed roller 26 A conveyance roller 28 that conveys the conveyed document after a predetermined location, a motor (not shown) that controls the rotation of the conveyance roller 28, and an image reading that reads an image of the document conveyed by the conveyance roller 28 at a reading position 32. Unit 15, paper discharge roller 30 for discharging the document read at reading position 32 of image reading unit 15, and paper discharge for placing the document discharged by paper discharge roller 30 And a ray 31.

  The paper feed roller 26 feeds the originals set on the original tray 25 one by one and conveys them to a predetermined location. The predetermined part is a part up to the reading position 32 of the image reading unit 15 that reads the image of the document, and in this embodiment, is the timing sensor 29. That is, the paper feed roller 26 conveys the document from the document tray 25 to the timing sensor 29. Here, the paper feed roller 26 operates as a first transport unit.

  The conveyance roller 28 conveys the document after a predetermined location. In other words, the conveyance roller 28 conveys the document after the timing sensor 29 and also conveys the document at the reading position 32 of the image reading unit 15. Here, the conveyance roller 28 operates as a second conveyance unit.

  The timing sensor 29 detects the leading edge of the document conveyed by the paper feed roller 26. Here, the timing sensor 29 operates as detection means.

  The image reading unit 15 is provided below the reading position 32. The image reading unit 15 includes a light source (not shown), a plurality of mirrors, a lens, and a CCD (Charge Coupled Device) image sensor. The image reading unit 15 reads an image of the document conveyed at the reading position 32 by the conveyance roller 28. Specifically, when the light source irradiates the reading position 32 with light, the irradiated light hits the document conveyed at the reading position 32 and is reflected. The reflected light is collected by a plurality of mirrors and lenses. This condensed light is read by a CCD image sensor. In this way, the image reading unit 15 reads the image of the document at the reading position 32.

  FIG. 3 is a flowchart showing an operation when a plurality of documents are conveyed by the document feeder 14. With reference to FIGS. 1 to 3, in this embodiment, a case where two originals 33 and 34 are conveyed by the original feeder 14 will be described.

  First, the first document 33 is conveyed to the timing sensor 29 (in FIG. 3, step S11, and the following steps are omitted). Specifically, rotation of the paper feed roller 26 is started by the transport motor 27 to feed and transport the first document 33. The speed at which the document is conveyed by the paper feed roller 26 is set in advance, for example, 100 mm / second.

  The timing sensor 29 detects the leading edge of the first document 33. Then, the control unit 11 measures the time from the start of rotation of the paper feed roller 26 to the timing sensor 29, that is, the time when the document 33 is conveyed by the paper feed roller 26 (S12). The first document 33 is continuously conveyed by the conveying roller 28 after the timing sensor 29 (S13). At this time, the speed at which the document is transported by the transport roller 28 is set in advance, and is set to 100 mm / second, which is the same as that of the paper feed roller 26, for example. The transport roller 28 transports the first document 33 at the set document transport speed. The image reading unit 15 reads the image of the first document 33 conveyed by the conveying roller 28 at the reading position 32 (S14).

  The control unit 11 determines whether or not the measured time is later than the predetermined time (S15). Specifically, if the predetermined time is 1 second and the measured time is 1.05 seconds, it is determined that the time is 0.05 seconds later than the predetermined time (YES in S15). Here, the control unit 11 operates as a determination unit.

  Then, the control unit 11 calculates a delay amount when the document 33 is conveyed by the paper feed roller 26. Specifically, the delay amount of the actual document conveyance speed is calculated with respect to the set document conveyance speed (S16). Here, the control unit 11 operates as calculation means. In this case, the measured time is 0.05 seconds later than the predetermined time. Therefore, first, the actual document transport speed is calculated to be 95 mm / second. The actual document transport speed is calculated as 95% of the set document transport speed from 95 mm / second ÷ 100 mm / second × 100. That is, the actual document transport speed is calculated to be 5% slower than the set document transport speed.

  Then, the control unit 11 changes the speed at which the document is transported by the paper feed roller 26 based on the delay amount of the actual document transport speed (S17). Specifically, since the actual document transport speed is 5% slower than the set document transport speed, the actual document transport speed is set to 5% faster than the set document transport speed. That is, the speed at which the document is increased is 100 mm / second × 5% + 100 mm / second = 105 mm / second. Here, the control unit 11 operates as changing means. Then, the paper feed roller 26 conveys the second original 34 to the timing sensor 29 at the accelerated original conveyance speed (S18).

  The timing sensor 29 detects the leading edge of the second document 34. Then, the second original 34 is continuously conveyed by the conveying roller 28 after the timing sensor 29 (S19). At this time, the conveyance roller 28 conveys the second original 34 at the original original conveyance speed of 100 mm / second as described above. The image reading unit 15 reads the image of the second original 34 conveyed by the conveying roller 28 at the reading position 32 (S20).

  By doing so, the document feeder 14 changes the speed at which the document is conveyed to a predetermined location from the document tray 25 to the reading position 32. As a result, even when a document transport delay occurs, the document transport speed is increased to a predetermined position from the document tray 25 to the reading position 32, thereby shortening the document transport time. Can do. At this time, the reading position 32 can be set at a speed different from the speed at which the original is transported from the original tray 25 to a predetermined location, so that the original image can be read appropriately. As a result, it is possible to shorten the time required for transporting the document and appropriately read the image of the document.

  Further, since the image forming apparatus includes the document feeding device 14 as described above, the time required for transporting the document is shortened, the image of the document is appropriately read, and the image is formed based on the read image of the document. can do.

  When it is determined in step S15 that the measured time is not later than the predetermined time (NO in S15), the control unit 11 is the speed at which the second original 34 is conveyed by the paper feed roller 26. Do not change. Accordingly, the paper feed roller 26 transports the second document 34 to the timing sensor 29 at the set document transport speed (S21).

  In the above-described embodiment, two continuous originals 33 and 34 are conveyed by the original feeder 14, and when the conveyance speed of the first original 33 is delayed, the second original 34 is conveyed. Although an example of increasing the speed has been described, the present invention is not limited to this, and three or more originals may be used. At this time, for example, it is assumed that six originals are conveyed and the delay amount of the conveyance speed of the first original is 5% slower as described above. Here, the speed at which the remaining five originals are conveyed by the paper feed roller 26 is increased by 1%. That is, the conveying speed of the five originals is 101 mm / second. In this way, the conveyance speed of the remaining originals may be increased so that the speed when conveying a plurality of originals becomes a predetermined speed.

  In the above embodiment, the example in which the paper feed roller 26 conveys the original from the original tray 25 to the timing sensor 29 has been described. However, the present invention is not limited to this, and a predetermined distance from the original tray 25 to the reading position 32 is described. If it is a place, you may convey to that place.

  Further, in the above-described embodiment, an example has been described in which when the measured time is determined to be later than the predetermined time, the speed at which the document is conveyed by the paper feed roller 26 is changed. The speed at which the document is conveyed by the paper feed roller 26 may be changed without determining that it is later than the time.

  In the above-described embodiment, the control unit 11 has been described with respect to an example of a configuration provided in the digital multifunction peripheral 10, but is not limited thereto, and may be configured in the document feeder 14.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

1 is a block diagram illustrating a configuration of a digital multifunction peripheral when an image forming apparatus including a document feeder according to an embodiment of the present invention is applied to the digital multifunction peripheral. FIG. 3 is a diagram illustrating details of a document feeder. 6 is a flowchart illustrating an operation when a plurality of originals are conveyed by an original feeder.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Digital multifunction device, 11 Control part, 12 DRAM, 13 Operation part, 14 Document feeder, 15 Image reading part, 16 Image formation part, 17 Hard disk, 18 FAX communication part, 19 Network IF part, 20 Public line, 21 Network , 22 PC, 25 Document tray, 26 Feed roller, 27 Transport motor, 28 Transport roller, 29 Timing sensor, 30 Discharge roller, 31 Discharge tray, 32 Reading position, 33, 34 Document.

Claims (2)

A document tray for loading documents to be transported,
First conveying means for conveying the document to a predetermined position from the document tray to a reading position for reading the document;
A detecting unit provided at the predetermined position from the document tray to a reading position for reading the document and detecting a leading edge of the document conveyed by the first conveying unit;
Second conveying means for conveying the document after the predetermined position;
Changing means for changing the speed at which the original is conveyed by the first conveying means;
By measuring the time from when the driving of the first conveying means is started until the leading edge of the original set on the original tray is detected by the detecting means, the time for conveying the original is predetermined. Determination means for determining whether or not the time is later than
The determining means includes a calculating means for calculating a delay amount when the original is conveyed by the first conveying means,
The changing means increases the speed at which the original is conveyed by the first conveying means when the determining means determines that it is later than the predetermined time,
An original feeding device that uniformly increases a speed at which a plurality of originals are conveyed by the first conveying means so as to be a predetermined speed based on the delay amount. A document feeder according to claim 1 ;
An image forming apparatus comprising: an image forming unit that forms an image from a document conveyed by the document feeding device.

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