Document conveying device and image reading device

Abstract

To provide a document conveying device and an image reading device that facilitate removal of document sheets on an ejection tray.SOLUTION: A controller, in a standby state, (a) determines whether there is a document sheet is on an ejection tray 14 on the basis of a sensor signal from an ejection tray sheet sensor, (b1) when there is no document sensor on the ejection tray 14, arranges a paper feed tray 11 at a predetermined intermediate position, and (b2) when there is a document sheet on the ejection tray 14, arranges the paper feed tray 11 at a lower position P2 that is at a predetermined distance from a position P0 where a paper feed tray upper limit sensor 42 detects that the paper feed tray 11 reaches an upper limit height. Here, the lower position P2 is a position higher than the intermediate position.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a document conveying device and an image reading device.

Background Art

[0002] A certain document conveying device includes a paper feed tray that can move up and down and a paper discharge tray, and conveys a document sheet along a conveyance path from the paper feed tray to the paper discharge tray via a discharge port (see, for example, Patent Document 1). In this document conveying device, when the paper feed tray moves up and down according to the thickness of the stack of document sheets on the paper feed tray, the discharge port also moves up and down in conjunction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a document sheet is removed from the paper feed tray while the document conveying device is in a standby state, it is conceivable to arrange the paper feed tray at a specific intermediate position so that a document sheet can be loaded on the paper feed tray and the document sheet on the paper discharge tray can be easily removed. In that case, a sensor for detecting the paper feed tray at the specific intermediate position is installed.

[0005] However, in this case, if a large number of document sheets are stacked on the discharge tray, the gap between the upper surface of the stack of document sheets on the discharge tray and the paper feed tray becomes narrow, making it difficult to remove the document sheets on the discharge tray.

[0006] The present invention has been made in view of the above problems, and an object thereof is to obtain a document conveying device and an image reading device that facilitate the removal of document sheets on the paper discharge tray.

Means for Solving the Problems

[0007] The document conveying device according to the present invention includes a paper feed tray on which a document sheet is placed, a discharge tray for the document sheet, a conveying device that conveys the document sheet along a conveyance path from the paper feed tray to the discharge tray, a discharge port that discharges the document sheet to the discharge tray at the end of the conveyance path, a first elevating device that raises and lowers the paper feed tray, a paper feed tray upper limit sensor that detects that the paper feed tray has reached the upper limit height, a discharge tray sheet sensor that detects the document sheet on the discharge tray, and a controller that controls the first elevating device and changes the height position of the paper feed tray. And, in the standby state, the controller (a) determines whether there is a document sheet on the discharge tray based on the sensor signal of the discharge tray sheet sensor, and (b1) when there is no document sheet on the discharge tray, arranges the paper feed tray at a predetermined intermediate position, and (b2) when there is a document sheet on the discharge tray, arranges the paper feed tray at a position a predetermined distance below the position where it is detected by the paper feed tray upper limit sensor that the paper feed tray has reached the upper limit height. Here, the lower position is higher than the intermediate position.

[0008] The image reading device according to the present invention includes the above-described document conveying device and an image sensor that reads an image of the document sheet at a predetermined position in the conveyance path.

Advantages of the Invention

[0009] According to the present invention, a document conveying device and an image reading device in which it is easy to remove a document sheet on the discharge tray can be obtained.

[0010] The above or other objects, features, and advantages of the present invention will become more apparent from the following detailed description together with the accompanying drawings.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0013] FIG. 1 is a side view showing the internal configuration of an image reading apparatus according to an embodiment of the present invention. The image reading apparatus shown in FIG. 1 is an apparatus such as a scanner machine, a copying machine, a facsimile machine, a multifunction machine, etc., and includes an automatic document feeder as a document conveying apparatus.

[0014] The image reading apparatus shown in FIG. 1 includes an apparatus main body 1, contact glasses 1a and 1b arranged on the upper surface of the apparatus main body 1, an image sensor 2, and a document cover 3. The document cover 3 includes an automatic document feeder 4.

[0015] The contact glass 1a is a transparent member on which a document is placed when performing image reading without using the automatic document feeder 4. Further, the contact glass 1b is a transparent member through which the document passes when performing image reading of the document image while automatically conveying the document by the automatic document feeder 4.

[0016] The image sensor 2 reads a document image from the document sheet. Specifically, when the image sensor 2 reads the image of the document while automatically conveying the document by the automatic document feeder 4, the image sensor 2 is a sensor that optically reads the document image of the document passing through a predetermined image reading position in the document conveyance path. The image sensor 2 reads the document image line by line. The image sensor 2 includes a light source (such as a light-emitting diode) and a light-receiving element (such as a line sensor), emits light with the light source, detects the reflected light reflected by the document or the like through the contact glasses 1a and 1b with the light-receiving element, and outputs an electrical signal corresponding to the amount of the reflected light. The controller 23 described later receives this electrical signal and generates a document image (that is, the image data of the document image) based on this electrical signal.

[0017] The document cover 3 is a member that can be in surface contact with the contact glass 1a and is rotatably installed, which makes the document adhere closely to the contact glass 1a and prevents ambient light from entering the inside of the apparatus from the contact glasses 1a and 1b during image reading. Further, the automatic document feeder 4 includes a paper feed tray 11 on which the document sheet is placed, and a conveyance device 21 that conveys the document sheet from the paper feed tray 11 to the discharge tray 14 through the reading position of the image sensor 2. The conveyance device 21 passes the document sheets placed on the paper feed tray 11 one by one over the contact glass 1b and discharges them to the discharge tray 14. Specifically, the conveyance device 21 includes a paper feed unit 12 and conveyance rollers 13 along the conveyance path, and the paper feed unit 12 feeds the document sheet and conveys it by the conveyance rollers 13. The paper feed unit 12 includes a paper feed roller 12a, a drive roller 12b, a driven roller 12c, a conveyance belt 12d, and an auxiliary roller 12e, and the paper feed roller 12a draws the document sheets on the paper feed tray 11 one by one along the conveyance belt 12d into the conveyance path.

[0018] The image sensor 2 can change its image reading position by a driving device (not shown). When performing image reading using the automatic document feeder 4, the image reading position of the image sensor 2 is set to the passing position of the document on the contact glass 1b. The image sensor 2 optically reads the image of the document conveyed by the automatic document feeder 4 when it passes over the contact glass 1b. Here, the image sensor 2 is a color image sensor and reads the document images of multiple colors such as RGB at different image reading positions in the conveyance direction. In this embodiment, a CIS (Contact Image Sensor) is used as the image sensor 2, and when performing image reading using the automatic document feeder 4, the image sensor 2 is disposed directly below the contact glass 1b.

[0019] Note that the paper feed roller 12a, the drive roller 12b, and the conveyance roller 13 are driven by a driving device (not shown) such as a motor.

[0020] The discharge tray 14 is a tray on which the document sheets discharged and dropped from the discharge port 15 at the end of the conveyance path are stacked. The discharge port 15 discharges the document sheets to the discharge tray 14 at the end of the conveyance path.

[0021] Furthermore, the image reading device shown in FIG. 1 includes a lifting device 22 that lifts and lowers the paper feed tray 11 by an existing lifting method, and a lifting device 23 that lifts and lowers the discharge port 15. Specifically, the lifting device 23 rotates the end conveyance path 16 together with the conveyance roller 13 at the end of the conveyance path about a predetermined fulcrum to lift and lower the discharge port 15.

[0022] FIG. 2 is a block diagram showing the electrical configuration of the automatic document feeder 4 in FIG. 1. As shown in FIG. 2, the image reading device further includes a paper feed tray sheet sensor 41, a paper feed tray upper limit sensor 42, a paper feed tray back sensor 43, a discharge tray sheet sensor 44, a discharge tray sheet amount sensor 45, and a controller 51.

[0023] The sheet feeding tray sheet sensor 41 detects the document sheet on the sheet feeding tray 11 and outputs a sensor signal indicating the presence or absence of the document sheet.

[0024] The sheet feeding tray upper limit sensor 42 is a sensor that detects that the sheet feeding tray 11 has reached the upper limit height. Specifically, the sheet feeding tray upper limit sensor 42 detects that the sheet feeding tray 11 or the document sheet placed on the sheet feeding tray 11 has come into contact with the sheet feeding roller 12a.

[0025] The back side sensor 43 of the sheet feeding tray detects contact with an object (such as a document sheet on the discharge tray 14) disposed on the back side of the sheet feeding tray 14.

[0026] The discharge tray sheet sensor 44 detects the document sheet on the discharge tray 14 and outputs a sensor signal indicating the presence or absence of the document sheet.

[0027] The discharge tray sheet amount sensor 45 detects the amount (thickness of the sheet bundle) of the document sheets on the discharge tray 14.

[0028] The controller 51 includes a processor that executes a program, an ASIC (Application Specific Integrated Circuit), etc., controls the automatic document feeder 4 (such as the conveying device 21 and the elevating device 22) to convey the document sheet, and executes image reading by the image sensor 2 to obtain image data of the image of the document sheet (document image).

[0029] Also, the controller 51 controls the elevating device 22 to change the height position of the sheet feeding tray 11, and controls the elevating device 23 to change the height position of the discharge port 15.

[0030] FIG. 3 is a diagram for explaining the height position of the sheet feeding tray 11 when there is no document sheet on the discharge tray 14. FIG. 4 is a diagram for explaining the height position of the sheet feeding tray 11 when there is a document sheet on the discharge tray 14.

[0031] Specifically, in the standby state (a state where the original sheet is not being conveyed), the controller 51 determines whether there is an original sheet on the discharge tray 14 based on the sensor signal of the discharge tray sheet sensor 44. (b1) When there is no original sheet on the discharge tray 14, for example, as shown in FIG. 3, the paper feed tray 11 is arranged at a predetermined intermediate position P1. (b2) When there is an original sheet on the discharge tray 14, for example, as shown in FIG. 4, the paper feed tray 11 is arranged at a lower position P2 that is a predetermined distance below the position (hereinafter also referred to as the upper limit height position P0) where it is detected by the paper feed tray upper limit sensor 42 that the paper feed tray 11 has reached the upper limit height. Here, the above-mentioned lower position P2 is a position higher than the above-mentioned intermediate position P1.

[0032] For example, the lower position P2 is a position where the paper feed tray 11 is moved downward from the upper limit height position P0 for 300 milliseconds.

[0033] Also, when there is no original sheet on the discharge tray 14, the controller 51 moves the paper feed tray 11 by a predetermined descent distance from the upper limit height position P0 and arranges the paper feed tray 11 at the intermediate position P1. Here, the descent distance may be half of the distance between the upper limit height position P0 and the lower limit height of the paper feed tray 11 (the position where the paper feed tray 11 is detected by a lower limit sensor not shown), or it may be settable by the user.

[0034] Also, when the paper feed tray 11 is descending (for example, before the paper feed tray 11 reaches the intermediate position P1 or the lower position P2), if the paper feed tray back sensor 43 detects contact of an object with the back side of the paper feed tray 11, the controller 51 stops the movement of the paper feed tray 11.

[0035] Also, when moving the paper feed tray 11, when the sensor signal of the discharge tray sheet sensor 44 changes (that is, when the original sheet on the discharge tray 14 is removed or an original sheet is placed on the discharge tray 14), after the elapse of a predetermined period (for example, 1 second), the controller 51 starts the movement of the paper feed tray 11. Thereby, contact of the user's hand or the like with the paper feed tray 11 is suppressed.

[0036] Further, regardless of the height position of the paper feed tray 11, the controller 51 arranges the discharge port 15 to be at a height position of a predetermined fixed distance from the upper surface of the stack of original sheets on the discharge tray 14 based on the detected amount of original sheets.

[0037] FIG. 5 is a diagram for explaining the height position of the discharge port 15 when there are few original sheets on the discharge tray 14. FIG. 6 is a diagram for explaining the height position of the discharge port 15 when there are many original sheets on the discharge tray 14. FIG. 7 is a diagram for explaining the height position of the discharge port 15 when there are few original sheets on the paper feed tray 11.

[0038] For example, as shown in FIGS. 5 and 6, according to the amount (thickness of the stack of sheets) of the original sheets 101 on the discharge tray 14, the discharge port 15 is arranged at a fixed height H from the upper surface of the stack of sheets. Thereby, the distance from the discharge port 15 to the upper surface of the stack of sheets in the discharge tray 14 becomes constant regardless of the height position of the paper feed tray 11, and variations in the position of the original sheets 101 stacked on the discharge tray 14 due to the fall from the discharge port 15 are suppressed. In particular, for example, as shown in FIG. 7, even when there are few original sheets 102 on the paper feed tray 11, the discharge port 15 is arranged at a height H from the upper surface of the stack of sheets without being interlocked with the height position of the paper feed tray 11, so that variations in the position of the original sheets 101 stacked on the discharge tray 14 are suppressed.

[0039] Next, the operation of the above image reading apparatus will be described.

[0040] (a) Standby state

[0041] In the standby state, the controller 51 monitors the sensor signal of the paper feed tray sheet sensor 41 and the sensor signal of the discharge tray sheet sensor 44, and determines whether there is an original sheet on the discharge tray 14 based on the sensor signal of the discharge tray sheet sensor 44.

[0042] When it is determined that there is no original sheet on the discharge tray 14, the controller 51 first moves the paper feed tray 11 to the upper limit height position and then moves the paper feed tray 11 to the intermediate position P1.

[0043] On the other hand, when it is determined that there is an original sheet 101 on the discharge tray 14, the controller 51 first moves the paper feed tray 11 to the upper limit height position and then moves the paper feed tray 11 to the lower position P2.

[0044] By doing so, when there is an original sheet 101 on the discharge tray 14, the gap between the stack of sheets on the discharge tray 14 and the paper feed tray 11 becomes wider, making it easier for the user to remove the original sheet 101 on the discharge tray 14. Also, when there is no original sheet 101 on the discharge tray 14, the gap between the paper feed unit 12 and the paper feed tray 11 becomes wider, making it easier for the user to place the original sheet on the paper feed tray 11.

[0045] (b) During the conveyance of the original sheet

[0046] When the original sheet is placed on the paper feed tray 11, the controller 51 raises the paper feed tray 11 until the original sheet contacts the paper feed roller 12a (that is, until it is detected by the paper feed tray upper limit sensor 42 that the paper feed tray 11 has reached the upper limit height). Then, when starting the conveyance of the original sheet, the controller 51 conveys the original sheets on the paper feed tray 11 one by one to the discharge tray 14. At this time, as the number of original sheets on the paper feed tray 11 decreases, the controller 51 changes the height position of the paper feed tray 11 so that the original sheet on the paper feed tray 11 abuts against the paper feed roller 12a, and as the number of original sheets 101 on the discharge tray 14 increases, the controller 51 changes the height position of the discharge port 15.

[0047] As described above, according to the above embodiment, in the standby state, the controller 51 determines whether there is an original sheet on the discharge tray 14 based on the sensor signal of the discharge tray sheet sensor 44, and (b1) when there is no original sheet on the discharge tray 14, arranges the paper feed tray 11 at a predetermined intermediate position, and (b2) when there is an original sheet on the discharge tray 14, arranges the paper feed tray 11 at a lower position a predetermined distance from the position where it is detected by the paper feed tray upper limit sensor 42 that the paper feed tray 11 has reached the upper limit height. Here, the lower position is higher than the intermediate position.

[0048] Thereby, since the height position of the paper feed tray 11 is changed according to the presence or absence of the original sheet on the discharge tray 14, it becomes easier to remove the original sheet on the discharge tray 14.

[0049] Various changes and modifications to the above-described embodiment will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the subject matter and without diminishing the intended advantages. That is, it is intended that such changes and modifications be included in the claims.

Industrial Applicability

[0050] The present invention is applicable to, for example, an image reading apparatus.

Explanation of Signs

[0051] 4 Automatic document feeder (an example of a document conveyance device) 15 Discharge port 21 Conveyance device 22 Lifting device (an example of a first lifting device) 23 Lifting device (an example of a second lifting device) 41 Paper feed tray sheet sensor 42 Paper feed tray upper limit sensor 43 Paper feed tray back sensor 44 Discharge tray sheet sensor 45 Discharge tray sheet amount sensor 51 Controller

Claims

1. A paper feed tray on which an original sheet is placed, A discharge tray for the original sheet, A conveying device that conveys the original sheet along a conveyance path from the paper feed tray to the discharge tray, An outlet that discharges the original sheet to the discharge tray at the end of the conveyance path, A first elevating device that raises and lowers the paper feed tray, A paper feed tray upper limit sensor that detects that the paper feed tray has reached the upper limit height, A discharge tray sheet sensor that detects the original sheet on the discharge tray, A controller that controls the first elevating device to change the height position of the paper feed tray, and In the standby state, the controller determines whether there is an original sheet on the discharge tray based on the sensor signal of the discharge tray sheet sensor, and (b1) when there is no original sheet on the discharge tray, arranges the paper feed tray at a predetermined intermediate position, and (b2) when there is an original sheet on the discharge tray, arranges the paper feed tray at a position below a predetermined distance from the position where it is detected by the paper feed tray upper limit sensor that the paper feed tray has reached the upper limit height, The lower position is higher than the intermediate position, An original sheet conveying device characterized by the above.

2. When there is no original sheet on the discharge tray, the controller moves the paper feed tray by a predetermined descending distance from the position where it is detected by the paper feed tray upper limit sensor that the paper feed tray has reached the upper limit height, and arranges the paper feed tray at the intermediate position, The descending distance can be set by the user, The original sheet conveying device according to claim 1, characterized by the above.

3. Further comprising a paper feed tray back sensor disposed on the back side of the paper feed tray to detect contact of an object, When the controller detects contact of an object on the back side of the paper feed tray by the paper feed tray back sensor before the paper feed tray reaches the intermediate position or the lower position, the controller stops the movement of the paper feed tray, The original sheet conveying device according to claim 1, characterized by the above.

4. When the sensor signal of the discharge tray sheet sensor changes, the controller starts the movement of the paper feed tray after a lapse of a predetermined period. The original sheet conveying device according to claim 1 is characterized by the above.

5. a second lifting device for lifting the discharge port, and a discharge tray sheet amount sensor for detecting the amount of the original sheets on the discharge tray; the controller controls the first lifting device and the second lifting device to change the height position of the paper feed tray and the height position of the discharge port; regardless of the height position of the paper feed tray, the controller arranges the discharge port so as to be at a height position of a predetermined constant distance from the upper surface of the stack of original sheets on the discharge tray based on the detected amount of the original sheets; The original sheet conveying device according to claim 1, characterized in that.

6. an original sheet conveying device according to any one of claims 1 to 5; an image sensor for reading an image of the original sheet at a predetermined position in the conveyance path; An image reading device, characterized by comprising.

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