Document feeder and image forming apparatus

Abstract

To provide a document feeder and an image forming apparatus that can effectively prevent trouble that may occur when receiving, during conveyance of documents, a predetermined request for stopping the conveyance of the documents.SOLUTION: A document feeder 200 causes a document conveying unit 201 to start successive conveyance (image reading) of documents G on a document placement tray 210 that are located at a document drawing position P1 by a tray lifting unit 211. After starting the successive conveyance of the documents G, when receiving, in the middle of the conveyance of the documents G, a predetermined request for stopping the conveyance of the documents G, the document feeder 200 stops the conveyance of the documents G, and performs an intermediate position lowering operation of causing the tray lifting unit 211 to lower the document placement tray 210, by a predetermined amount, from the document drawing position P1 to an intermediate position P3 higher than a lowest position P2.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present invention relates to a document feeder and an image forming apparatus such as a copying machine, a multifunction machine, a printer, or a facsimile machine. [Background technology]

[0002] A conventional document feeding device is known that includes a document loading tray that can be raised and lowered between a document loading position where documents are loaded and a lowest position, a tray lifting unit that raises and lowers the document loading tray, a document transport unit that loads and transports documents loaded on the document loading tray one by one while the document loading tray is positioned at the document loading position by the tray lifting unit, and a document set detection unit that is provided on the document loading tray and detects whether or not a document is set on the document loading tray (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-199065 Summary of the Invention [Problem to be solved by the invention]

[0004] In such a document feeder, when a predetermined request to stop the transport of a document is received during the transport of the document, the following inconveniences occur: Here, examples of the predetermined request include a prescan request that requests a prescan in which only the image of a portion of multiple documents (for example, one document) is read in advance as image data, a document reset request that requests the document to be reset when a document transport failure is detected during the transport of the document by the document transport unit, and a transport cancel request that requests the document transport to be canceled during the transport of the document by the document transport unit.

[0005] 14A and 14B are cross-sectional views illustrating inconveniences that may occur in conventional document feeder 200X when a predetermined request to stop transport of document G is received midway through transport of document G. Figures 14A and 14B show the document stacking tray 210 positioned at document feed position P1 and lowest position P2, respectively.

[0006] The document feeder 200X includes a document loading tray 210 that can be raised and lowered between a document feed position P1 where the document G is loaded and a lowest position P2, a tray lifting unit 211 that raises and lowers the document loading tray 210, a document transport unit 201 that loads and transports the documents G loaded on the document loading tray 210 one by one while the document loading tray 210 is positioned at the document feed position P1 by the tray lifting unit 211, and a document set detection unit 293 that is provided on the document loading tray 210 and detects whether or not the document G is set on the document loading tray 210. Here, the document feed position P1 is a position where the document G is loaded in order to be transported by the document transport unit 201.

[0007] In the conventional document feeding device 200X, after the document transport unit 201 starts continuous transport of the document G on the document loading tray 210 positioned at the document feed position P1 (see Figure 14A) by the tray lifting unit 211, if a specific request to stop the transport of the document G (e.g., a pre-scan request, a document re-setting request, or a transport cancellation request) is received during the transport of the document G, the document loading tray 210 is lowered from the document feed position P1 to the lowest position P2 (see Figure 14B) to enable the user to reset the document G.

[0008] 14B, leading edges G1 of all documents G on document stacking tray 210 may remain at document supply position Q of document transport unit 201. In this case, the distance between document set detection unit 293 on document stacking tray 210 and a detected portion G2 of document G relative to document set detection unit 293 exceeds the effective detection distance of document set detection unit 293, and document set detection unit 293 is unable to detect that documents G have been set on document stacking tray 210. In other words, document feeder 200X recognizes that documents G are not set on document stacking tray 210, and is unable to fulfill a predetermined request. This is particularly noticeable when there are only a few documents G remaining on document stacking tray 210.

[0009] In this regard, Patent Document 1 does not address the inconvenience that may occur when a predetermined request to stop transport of a document is received in the middle of transporting the document.

[0010] Therefore, an object of the present invention is to provide a document feeder and an image forming apparatus that can effectively prevent inconveniences that may occur when a specific request to stop transport of a document is received during transport of the document. [Means for solving the problem]

[0011] In order to solve the above problem, the document feeding device of the present invention includes a document loading tray that can be raised and lowered between a document feed position where documents are loaded and a lowest position, a tray lifting unit that raises and lowers the document loading tray, a document transport unit that loads and transports the documents loaded on the document loading tray one by one while the tray lifting unit positions the document loading tray at the document feed position, and a document set detection unit that is provided on the document loading tray and detects whether the documents are set on the document loading tray, wherein after the document transport unit starts continuous transport of the documents on the document loading tray positioned at the document feed position by the tray lifting unit, when a predetermined request to stop transport of the documents is received during transport of the documents, the document feeding device stops transport of the documents and performs an intermediate position lowering operation by the tray lifting unit to lower the document loading tray by a predetermined amount from the document feed position to an intermediate position that is higher than the lowest position. [Effects of the Invention]

[0012] According to the present invention, it is possible to effectively prevent inconveniences that may occur when a predetermined request to stop transport of a document is received midway through the transport of the document. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus including a document feeder according to an embodiment of the present invention; [Figure 2] 1 is a perspective view showing a document feeder according to an embodiment of the present invention; [Figure 3] 2 is an enlarged cross-sectional view showing an enlarged document transport portion of the document feeder; FIG. [Figure 4] FIG. 2 is a schematic block diagram showing a control configuration for controlling the operation of the document feeder. [Figure 5] FIG. 2 is a schematic side view of a document transport unit in the document feeder. [Figure 6A] FIG. 2 is a perspective view showing a document feeder. [Figure 6B] FIG. 2 is an enlarged perspective view showing an enlarged view of a document set detection unit portion in the document feeder. [Figure 7] 2 is a perspective view of the document feeder with the document stacking tray removed, showing the front side of the document set detector and the tray lifting unit as viewed obliquely from above; FIG. [Figure 8] 2 is a perspective view of the tray lifting section of the document feeder with the document loading tray removed, viewed obliquely from above on the rear side; FIG. [Figure 9A] FIG. 10 is a perspective view of the front side of the document feed position detection unit with one of the transport guides removed, viewed obliquely from above. [Figure 9B] 9B is an enlarged perspective view showing an enlarged view of the document feed position detection unit portion in FIG. 9A. FIG. [Figure 10A] 6B is a perspective view showing a cross section of the document feeder taken along line AA shown in FIG. 6A. FIG. [Figure 10B] 10B is an enlarged perspective view showing a bottom-most position detection unit portion in FIG. 10A. FIG. [Figure 11A] FIG. 4 is a cross-sectional view showing a state in which the document stacking tray is positioned at a document loading position. [Figure 11B] FIG. 10 is a cross-sectional view showing a state in which the document stacking tray is positioned at the lowest position. [Figure 11C] FIG. 10 is a cross-sectional view showing a state in which the document stacking tray is positioned at an intermediate position. [Figure 12] 10 is a flowchart showing an example of a process flow of a document setting operation in a document transport operation by a control unit. [Figure 13] 10 is a flowchart showing an example of the flow of processing of a document reading operation in a document transport operation by a control unit. [Figure 14A] 10A and 10B are cross-sectional views illustrating inconveniences that may occur when a predetermined request to stop transport of a document is received in the middle of transporting the document in a conventional document feeder. [Figure 14B] 10A and 10B are cross-sectional views illustrating inconveniences that may occur when a predetermined request to stop transport of a document is received in the middle of transporting the document in a conventional document feeder. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. The names and functions of these components are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0015] [Image forming equipment] Fig. 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus 100 equipped with a document feeder 200 according to the present embodiment. In Fig. 1, the symbol X indicates the horizontal direction (left-right direction), the symbol Y indicates the depth direction (front-rear direction), and the symbol Z indicates the vertical direction (height direction).

[0016] The image forming apparatus 100 is a multifunction machine having a copy function, a scanner function, a facsimile function, and a printer function, and reads an image of an original G as image data using an image reading device 102, and transmits the read image data of the original G to an external device. The image forming apparatus 100 also forms an image on paper (recording material) in color or monochrome using the image data of the original G read by the image reading device 102 or image data received from an external device. Note that the image forming apparatus 100 may also form a monochrome image.

[0017] The image reading device 102 includes a document feeder 200. The document feeder 200 is provided above the image reading unit 130 and is supported so as to be openable and closable relative to the image reading unit 130. The document feeder 200 sequentially transports one or more documents G, G to G one by one. The image reading device 102 reads the documents G transported one by one from a document stacking tray 210 by the document feeder 200. The image reading device 102 includes a document placing table 130a (document table) on which the documents G are placed, and reads the documents G placed on the document placing table 130a. When the document feeder 200 is opened, the document placing table 130a above the image reading unit 130 is opened, allowing the documents G to be placed manually. Furthermore, the document feeding device 200 is equipped with a document loading tray 210 on which documents G are loaded, and a document discharge tray 250 on which documents G that have been discharged to the outside are loaded. The image reading device 102 reads the documents G that are loaded on the document loading tray 210 and transported by the document feeding device 200. The document feeding device 200 transports the documents G loaded (placed) on the document loading tray 210 one by one onto the document reading unit 130b in the image reading unit 130. The image reading unit 130 scans the scanning optical system 130c to read the documents G placed on the document placing table 130a or reads the documents G transported by the document feeding device 200, and generates image data.

[0018] The image forming apparatus 100 includes an image forming unit 110. The image forming unit 110 includes an optical scanning device 1, a developing device 2, a photosensitive drum 3, a drum cleaning device 4, a charger 5, an intermediate transfer belt 7, a fixing device 12, a paper transport path S, a paper feed cassette 18, and a paper discharge tray 141 (internal discharge tray).

[0019] The image forming unit 110 handles image data corresponding to color images using black (K), cyan (C), magenta (M), and yellow (Y), or monochrome images using a single color (e.g., black). The image transfer unit 50 of the image forming apparatus 100 is provided with four developing devices 2, four photosensitive drums 3, four drum cleaning devices 4, and four chargers 5 for forming four types of toner images, each corresponding to black, cyan, magenta, and yellow, and forming four image stations Pa, Pb, Pc, and Pd.

[0020] The optical scanning device 1 exposes the surface of the photosensitive drum 3 to light to form an electrostatic latent image. The developing device 2 develops the electrostatic latent image on the surface of the photosensitive drum 3 to form a toner image on the surface of the photosensitive drum 3. The drum cleaning device 4 removes and collects residual toner on the surface of the photosensitive drum 3. The charger 5 uniformly charges the surface of the photosensitive drum 3 to a predetermined potential. Through the series of operations described above, a toner image of each color is formed on the surface of each photosensitive drum 3.

[0021] An intermediate transfer roller 6 is disposed above the photosensitive drum 3 via an intermediate transfer belt 7. The intermediate transfer belt 7 is stretched around a transfer drive roller 7a and a transfer driven roller 7b, and moves in a circular motion in the direction of arrow C. In the image forming apparatus 100, a belt cleaning device 9 removes and collects residual toner, and the toner images of each color formed on the surface of each photosensitive drum 3 are sequentially transferred and superimposed to form a color toner image on the surface of the intermediate transfer belt 7.

[0022] A nip is formed between the transfer roller 11a of the secondary transfer unit 11 and the intermediate transfer belt 7, and the toner image on the intermediate transfer belt 7 is transferred to the paper that has been conveyed to the nip. When the paper passes through the nip, the toner image on the surface of the intermediate transfer belt 7 is transferred to the paper, and the paper is conveyed to the fixing device 12.

[0023] The fixing device 12 includes a fixing roller 12a and a pressure roller 12b that rotate while sandwiching the paper. The fixing device 12 sandwiches the paper onto which the toner image has been transferred between the fixing roller 12a and the pressure roller 12b, and applies heat and pressure to fix the toner image to the paper.

[0024] The paper feed cassette 18, which is a cassette for storing paper sheets used for image formation, is provided below the optical scanning device 1. The paper sheets are drawn out of the paper feed cassette 18 by a pick-up roller 16 and transported to a paper transport path S. The paper sheets transported to the paper transport path S pass through the secondary transfer unit 11 and the fixing device 12, are transported to a discharge roller pair 17, and are then discharged to a paper discharge tray 141. The paper transport path S is provided with a transport roller pair 13, a registration roller pair 14, and a discharge roller pair 17. The transport roller pair 13 facilitates the transport of the paper sheets. The registration roller pair 14 temporarily stops the paper sheets and aligns their leading edges. The registration roller pair 14 transports the stopped paper sheets in synchronization with the toner image on the intermediate transfer belt 7. The toner image on the intermediate transfer belt 7 is transferred to the paper sheets at the nip between the intermediate transfer belt 7 and transfer roller 11a. Although FIG. 1 shows one paper feed cassette 18, the present invention is not limited to this, and a configuration in which a plurality of paper feed cassettes 18 are provided may also be used.

[0025] Furthermore, when forming an image on the back side of a sheet of paper in addition to the front side, the image forming apparatus 100 transports the sheet in the reverse direction from the discharge roller pair 17 to the sheet reversal path Sr. The image forming apparatus 100 inverts the sheet transported in the reverse direction and guides it again to the registration roller pair 14. The image forming apparatus 100 also forms an image on the back side of the sheet of paper guided to the registration roller pair 14 in the same manner as on the front side, and then discharges the sheet to the sheet discharge tray 141.

[0026] The image reading unit 130 is provided on the top surface of the image forming apparatus main body 101. On the image reading unit 130, a document feeder 200 is attached.

[0027] [Document feeder] Fig. 2 is a perspective view showing document feeder 200 according to this embodiment. Fig. 3 is an enlarged cross-sectional view showing a document transport section 201 portion of document feeder 200. Fig. 4 is a schematic block diagram showing a control configuration for controlling the operation of document feeder 200. Fig. 5 is a schematic side view of document transport section 201 in document feeder 200.

[0028] Fig. 6A is a perspective view showing document feeder 200. Fig. 6B is an enlarged perspective view showing a document set detection unit 293 portion of document feeder 200. Fig. 7 is a perspective view of document feeder 200 with document stacking tray 210 removed, showing the front side of document set detection unit 293 and tray lifting unit 211 portion from diagonally above.

[0029] FIG. 8 is a perspective view of the tray lifting section 211 of the document feeder 200, with the document stacking tray 210 removed, viewed obliquely from above on the rear side.

[0030] Fig. 9A is a perspective view of the front side of the document feed position detection unit 291, with one transport guide 231a removed, viewed obliquely from above. Fig. 9B is an enlarged perspective view of the document feed position detection unit 291 in Fig. 9A.

[0031] Fig. 10A is a perspective view showing a cross section taken along line AA shown in Fig. 6A of document feeder 200. Fig. 10B is an enlarged perspective view showing a portion of bottom position detector 292 in Fig. 10A.

[0032] 11A, 11B, and 11C are cross-sectional views showing the document stacking tray 210 positioned at the document loading position P1, the lowest position P2, and the intermediate position P3, respectively.

[0033] The document feeder 200 includes a document stacking tray 210, a tray lifting / lowering unit 211, a document transport unit 201, and a control unit 260 (see FIG. 4).

[0034] <Document loading tray> The document stacking tray 210 holds documents G. The document stacking tray 210 is movable up and down between a document feed position P1 where the documents G are fed in order for the document feed unit 201 to feed the documents G, and a lowest position P2.

[0035] In detail, as shown in Figures 11A to 11C, the document loading tray 210 is provided in the document feeding device main body 200a so as to be freely rotatable around a rotation axis α (rotation axis 210a) along the width direction W perpendicular to the transport direction H of the document G.

[0036] <Tray lifting section> The tray lifting unit 211 drives the document stacking tray 210 so that the document stacking tray 210 moves up and down.

[0037] More specifically, the tray lifting unit 211 lifts and lowers the document stacking tray 210 between a document feed position P1 and a lowest position P2. As shown in FIGS. 7 and 8, the tray lifting unit 211 includes a rotation shaft 211a, a tray push-up unit 211b (lever member), and a tray drive unit 272 (see FIG. 4). The rotation shaft 211a is provided on the document feeder main body 200a so as to be rotatable about a rotation axis β (rotation shaft 211a) along the width direction W between the document stacking tray 210 and the bottom surface 200a1 of the document feeder main body 200a. The tray push-up unit 211b is fixed to the rotation shaft 211a between the document stacking tray 210 and the bottom surface 200a1 of the document feeder main body 200a. The tray push-up unit 211b extends from the rotation shaft 211a outward in the radial direction of the rotation shaft 211a.

[0038] As shown in FIG. 4 , the tray driving unit 272 rotates the rotary shaft 211a. The tray driving unit 272 is electrically connected to the output side of the control unit 260. Under the instruction of the control unit 260, the tray driving unit 272 rotates the rotary shaft 211a toward the document stacking tray 210, thereby rotating the tray push-up unit 211b upward, thereby pushing up the document stacking tray 210. This allows the tray lifting unit 211 to lift the document stacking tray 210. Further, under the instruction of the control unit 260, the tray driving unit 272 rotates the rotary shaft 211a toward the bottom surface 200a1 of the document feeding device main body 200a, thereby rotating the tray push-up unit 211b downward, thereby releasing the push-up operation of the tray push-up unit 211b against the document stacking tray 210. As a result, the tray push-up unit 211b descends under its own weight, allowing the tray lifting unit 211 to lower the document stacking tray 210.

[0039] As shown in FIG. 4, the tray lifting section 211 also has a document feed position detection section 291 and a bottom position detection section 292.

[0040] The document feed position detection unit 291 detects the document feed position P1 (see FIG. 11A) of the document stacking tray 210. That is, the document feed position detection unit 291 detects that the document G placed on the document stacking tray 210 has risen to the document feed position P1.

[0041] 9A and 9B, the document supply unit 220 includes a support member 225. The support member 225 rotatably supports a pickup roller 221 (pickup roller) and a supply roller 222 (sheet feed roller). The support member 225 is provided with a detected portion 225a (detectable piece). The document feed position detection unit 291 detects the presence or absence of the detected portion 225a by the elevation of the pickup roller 221 due to the elevation of the document stacking tray 210, that is, the elevation of the support member 225 in this example. The document feed position detection unit 291 transmits a signal (on / off signal) indicating the presence or absence of the detected portion 225a to the control unit 260. This allows the control unit 260 to detect whether the top sheet P on the document stacking tray 210 is positioned at the document feed position P1. In this example, the control unit 260 can detect that the uppermost sheet P on the document stacking tray 210 is positioned at the document feed position P1 by the document feed position detection unit 291 being turned on.

[0042] The bottom position detector 292 detects the bottom position P2 (lower limit position) of the document stacking tray 210 (see FIG. 11B).

[0043] Specifically, as shown in FIGS. 8, 10A, and 10B, tray push-up section 211b of tray lift-up section 211 is provided with detected section 211b1 (detected piece) (see FIGS. 8 and 10B). Bottom-most position detection section 292 detects the presence or absence of detected section 211b1 by the rotation of tray push-up section 211b caused by the rotation of rotation shaft 211a. Bottom-most position detection section 292 transmits a signal (on / off signal) indicating the presence or absence of detected section 211b1 to control section 260. This allows control section 260 to detect whether document stacking tray 210 is located at bottom position P2 (lowest limit position). In this example, control section 260 can detect that document stacking tray 210 is located at bottom position P2 by the bottom-most position detection section 292 being turned on.

[0044] 8 and 9B, the document feed position detection unit 291 and the lowest position detection unit 292 have light-emitting units 291a and 292a and light-receiving units 291b and 292b. The document feed position detection unit 291 and the lowest position detection unit 292 are light-transmitting sensors that detect whether light passing between the light-emitting units 291a and 292a and the light-receiving units 291b and 292b is blocked by the detected units 225a and 211b1. Note that the document feed position detection unit 291 and the lowest position detection unit 292 can be conventionally known units, and detailed description thereof will be omitted here.

[0045] <Document transport section> The document transport unit 201 transports the documents G loaded on the document loading tray 210 one by one while the document loading tray 210 is positioned at the document loading position P1 (see FIG. 11A) by the tray lifting unit 211.

[0046] In detail, the document transport unit 201 includes a document supply unit 220, a document feed unit 230, a transport drive unit 271 (see FIG. 4), a transport drive transmission mechanism 280 (see FIG. 4), a document discharge unit 240, and a document discharge tray 250. The document supply unit 220 supplies the documents G loaded on the document stacking tray 210 one by one to the document feed unit 230. The document feed unit 230 transports the documents G supplied by the document supply unit 220 based on the center in the width direction W. The document discharge unit 240 discharges the documents G transported by the document feed unit 230. The document discharge tray 250 holds the documents G discharged by the document discharge unit 240. In the document feeding device 200, the document stacking tray 210 and the document discharge tray 250 are arranged to overlap in the vertical direction Z.

[0047] 3, the document feed section 230 includes a pair of conveyance guides 231a and 231b that form a sheet conveyance path 231, a conveyance roller pair 232, a registration roller pair 233, a pre-reading conveyance roller pair 234, a post-reading conveyance roller pair 235, and a pre-discharge conveyance roller pair 236. The conveyance roller pair 232, the registration roller pair 233, the pre-reading conveyance roller pair 234, the post-reading conveyance roller pair 235, and the pre-discharge conveyance roller pair 236 are arranged in this order along the sheet conveyance path 231.

[0048] The document supply unit 220 includes a pick-up roller 221 , a supply roller 222 , a separation member 223 (a separation roller or a separation pad (in this example, a separation roller)), a supply drive transmission mechanism 224 , and a support member 225 .

[0049] The pick-up roller 221 picks up the topmost document G among the documents G placed on the document stacking tray 210. The supply roller 222 and the separation member 223 separate and transport the documents G picked up by the pick-up roller 221 one by one. The supply roller 222, together with the separation member 223, transports the documents G picked up by the pick-up roller 221 one by one toward the sheet transport path 231. The separation member 223 is disposed opposite the supply roller 222. The separation member 223 regulates the transport in the transport direction H of the second and subsequent documents G from the top among the documents G placed on the document stacking tray 210. The supply drive transmission mechanism 224 is composed of a gear train or pulleys and a belt, and transmits the rotational drive force sent to the supply roller 222 to the pick-up roller 221. The pick-up roller 221, the supply roller 222, and the separation member 223 are located in the center in the width direction W. This allows the document G to be fed by being read in at the center in the width direction W. The document feeder 220 is a conventionally known device, and other detailed configurations will not be described here.

[0050] The pair of conveying guides 231a, 231b form a sheet conveying path 231 between the document supply unit 220 and the document discharge unit 240. The sheet conveying path 231 has a reading position R (see FIGS. 3 and 5) at the bottom where an image of the document G is read.

[0051] The pair of conveying rollers 232, the pair of registration rollers 233, the pair of pre-reading conveying rollers 234, the pair of post-reading conveying rollers 235, and the pair of pre-discharge conveying rollers 236 are each composed of drive rollers 232a to 236a and driven rollers 232b to 236b. The document discharge section 240 is equipped with a pair of discharge rollers 241. The pair of discharge rollers 241 is composed of a drive roller 241a and a driven roller 241b.

[0052] 4, the transport driver 271 is electrically connected to the output system of the control unit 260. This allows the control unit 260 to drive the transport driver 271 at a predetermined timing. The transport drive transmission mechanism 280 transmits the rotational driving force from the transport driver 271 to the supply roller 222 and the drive rollers 232a to 236a, 241a.

[0053] The transport drive transmission mechanism 280 includes a resist clutch 281. The resist clutch 281 is provided on the drive roller 233a and is configured to be able to selectively switch between disconnection and connection of the rotational drive force to the drive roller 233a. The drive roller 233a is driven to rotate when the resist clutch 281 is turned on. The resist clutch 281 is electrically connected to an output system of the control unit 260. This allows the control unit 260 to turn the resist clutch 281 on and off at a predetermined timing.

[0054] The driven rollers 232b to 236b and 241b are rotated by the driving rollers 232a to 236a and 241a.

[0055] As shown in FIGS. 4 and 5, the document feeder 200 further includes a document set detector 293 (see FIGS. 6A and 6B), a first transport detector 294, and a second transport detector 295.

[0056] The document set detection unit 293, the first transport detection unit 294, and the second transport detection unit 295 all have a light-emitting unit and a light-receiving unit, and are light-reflection type photocouplers (optical sensors) that emit light from the light-emitting unit and receive reflected light from the document G at the light-receiving unit.

[0057] The document set detection unit 293 is provided on the document stacking tray 210. The document set detection unit 293 detects whether or not a document G is set on the document stacking tray 210. The document set detection unit 293 is electrically connected to an input system of the control unit 260.

[0058] The first transport detection unit 294 is provided upstream of the transport roller pair 232 in the transport direction H. The first transport detection unit 294 detects whether the document G has passed upstream of the transport roller pair 232. The first transport detection unit 294 is electrically connected to an input system of the control unit 260.

[0059] The second conveyance detection unit 295 is provided at a predetermined upstream side of the registration roller pair 233 in the conveyance direction H. The second conveyance detection unit 295 detects whether the document G has passed upstream of the registration roller pair 233. The second conveyance detection unit 295 is electrically connected to an input system of the control unit 260.

[0060] In this embodiment, the document set detection unit 293, the first transport detection unit 294, and the second transport detection unit 295 are configured to have light reflective sensors equipped with a light emitting unit and a light receiving unit, but the document set detection unit 293 may also be configured to have an actuator.

[0061] <Control unit> 4, the control unit 260 has a processing unit 261 made up of a computer such as a CPU (Central Processing Unit), and a storage unit 262 including a nonvolatile memory such as a ROM (Read Only Memory) and a volatile memory such as a RAM (Random Access Memory). Note that the control unit 260 may be provided in the image forming apparatus 100.

[0062] In the control unit 260, the processing unit 261 calls a control program stored in advance in the ROM of the storage unit 262, and when the control program is loaded onto the RAM of the storage unit 262, the control of the operation of the various components is executed.

[0063] (First embodiment) The control unit 260 starts continuous transport (image reading) of the originals G on the original stacking tray 210, which has been positioned at the original document feed position P1 by the tray lifting unit 211, by the original transport unit 201. After starting the continuous transport of the originals G, if the control unit 260 receives a predetermined request to stop the transport of the originals G midway through the transport of the originals G, the control unit 260 stops the transport of the originals G and performs an intermediate position lowering operation. That is, the control unit 260 has an intermediate position lowering operation mode M1 that executes the intermediate position lowering operation. The intermediate position lowering operation is an operation in which the tray lifting unit 211 lowers the original stacking tray 210 by a predetermined amount from the original document feed position P1 to an intermediate position P3 (see FIG. 11C) that is higher than the lowest position P2.

[0064] An example of the predetermined amount is the range between the position of the document stacking tray 210 at which the document set detection unit 293 can detect the document G and the position of the document stacking tray 210 at which the document G can be set (and will not become unset) by the document stacking tray 210. This allows the document set detection unit 293 to reliably detect whether the document G has been set, and also allows the user to smoothly set the document G on the document stacking tray 210.

[0065] In this example, if the tray drive unit 272 is a stepping motor, the predetermined amount can be a predetermined number of steps of the input signal to the stepping motor, and if the tray drive unit 272 is a DC brushless motor with an encoder, the predetermined amount can be a predetermined number of steps of the output signal of the encoder.

[0066] Examples of the predetermined request include a prescan request for requesting a prescan in which only the image of a portion (e.g., one sheet) of the multiple sheets of original document G is read as image data in advance; an original reload request for requesting reloading of original document G when a transport failure of original document G is detected during transport (image reading) of original document G by original document transport unit 201; and a transport cancel request for requesting cancellation of transport of original document G during transport (image reading) of original document G by original document transport unit 201. Examples of transport failures include detection of multiple feeds by first transport detection unit 294 and second transport detection unit 295, detection of a document jam, and detection of no paper feed (no paper feed of stapled or punched original document). Note that in response to a prescan request, after prescanning, a preview display is performed to display the read image data, and when the portion (e.g., one sheet) of original document G whose image has been read is returned to the original document stacking tray 210, a main scan is performed to read all of the images of the multiple sheets of original document G as image data.

[0067] Furthermore, the control unit 260 detects whether or not an original G has been set on the original stacking tray 210 located at the intermediate position P3 using the original set detection unit 293. Then, the control unit 260 determines whether or not an original G has been set based on the detection result of the original set detection unit 293. That is, when the control unit 260 receives a signal (ON signal) indicating that an original G has been set from the original set detection unit 293, the control unit 260 determines that an original G has been set, and when the control unit 260 receives a signal (OFF signal) indicating that an original G has not been set from the original set detection unit 293, the control unit 260 determines that an original G has not been set.

[0068] According to this embodiment, when the control unit 260 receives a predetermined request to stop the transport of the original G during transport, the control unit 260 stops the transport of the original G and lowers the original G by a predetermined distance from the original feed position P1 to an intermediate position P3 that is higher than the lowest position P2. This allows the distance between the original set detector 293 on the original stacking tray 210 and the portion G2 of the original G to be detected by the original set detector 293 to be within the maximum detectable distance of the original G by the original set detector 293, even if the leading edge G1 of all the originals G on the original stacking tray 210 remains at the original supply position Q (the nip between the supply roller 222 and the separating member 223) of the original transport unit 201 (see FIG. 11C ). Here, the maximum detectable distance of the original G by the original set detector 293 is the farthest distance at which the original set detector 293 can detect the original G. This allows the predetermined request to be realized. Therefore, it is possible to effectively prevent inconveniences that may occur when a predetermined request to stop the transport of the original is received during the transport of the original, which is particularly effective when there are only a few originals G remaining on the original stacking tray 210.

[0069] In this embodiment, the control unit 260 detects whether or not a document G has been set on the document stacking tray 210 located at the intermediate position P3 using the document set detection unit 293, so that the document set detection unit 293 can detect that the document G has been set on the document stacking tray 210, i.e., the control unit 260 can recognize that the document G has been set on the document stacking tray 210.

[0070] In this embodiment, an example of the intermediate position is a position above the center position in the vertical direction Z of the maximum detectable distance of the document G by the document set detection unit 293 when the document loading tray 210 is lowered and the leading edge G1 of the document G on the document loading tray 210 remains at the document supply position Q, for example, a position within a range between the upper position and a lower position that is a predetermined distance below the upper position.

[0071] In this case, when the document stacking tray 210 is lowered from the document feed position P1 to the intermediate position P3, it is possible to shorten the time it takes for the document stacking tray 210 to reach the intermediate position P3.

[0072] (Second embodiment) In this embodiment, the specified request includes at least one of a pre-scan request that requests a pre-scan to read in advance the image of only a portion (for example, one sheet) of multiple sheets of original document G as image data; a document re-setting request that requests the original document G to be re-set when a transport failure of the original document G is detected during transport of the original document G by the original document transport unit 201; and a transport cancellation request that requests the cancellation of transport of the original document G during transport of the original document G by the original document transport unit 201.

[0073] This effectively prevents the document set detection unit 293 from mistakenly detecting that the document G has been set on the document stacking tray 210 when at least one of a pre-scan request, a document re-setting request, and a transport cancellation request is received as a specified request.

[0074] (Third embodiment) Incidentally, when the remaining amount of documents G on the document stacking tray 210 is greater than a predetermined reference remaining amount, normally, the leading ends G1 of all documents G on the document stacking tray 210 do not remain at the document supply position Q of the document transport unit 201. In this case, no inconvenience occurs when a predetermined request to stop the transport of documents G is received midway through the transport of documents G. Therefore, when the remaining amount of documents G on the document stacking tray 210 is greater than a predetermined reference remaining amount, it can be considered that the leading ends G1 of all documents G on the document stacking tray 210 do not remain at the document supply position Q of the document transport unit 201.

[0075] From this perspective, in this embodiment, after the tray lifting unit 211 starts continuous transport of the originals G on the original stacking tray 210 at the original feed position P1 by the original transport unit 201, if the control unit 260 receives a predetermined request to stop the transport of the originals G midway through the transport of the originals G, the control unit 260 stops the transport of the originals G, and if the remaining amount of the originals G on the original stacking tray 210 is greater than a predetermined reference remaining amount, performs a lowest position lowering operation without performing an intermediate position lowering operation. That is, the control unit 260 has a lowest position lowering operation mode M2 ​​that executes the lowest position lowering operation. The lowest position lowering operation is an operation that lowers the original stacking tray 210 from the original feed position P1 to the lowest position P2. The control unit 260 uses the original set detection unit 293 to detect whether the originals G have been set on the original stacking tray 210 located at the lowest position P2.

[0076] By doing this, when it is determined that the leading ends G1 of all the documents G on the document stacking tray 210 will not remain at the document supply position Q of the document transport section 201, the document stacking tray 210 is lowered to the lowest position without lowering to the intermediate position, thereby improving the ease with which the user can set the documents G on the document stacking tray 210.

[0077] Here, the remaining amount of documents G on document stacking tray 210 can be found, for example, as follows: That is, control unit 260 detects the initial number of documents G initially set on document stacking tray 210 based on the time (or the angle of document stacking tray 210 = the number of steps relative to tray drive unit 272) from when document set detection unit 293 detects that documents G have been set on document stacking tray 210 until document feed position detection unit 291 detects document feed position P1 of document stacking tray 210. Next, control unit 260 subtracts one document G from the initial number each time one document G is transported.

[0078] <Example of document transport operation control> Next, an example of control of the transport operation of the original G will be described below with reference to FIGS.

[0079] -Example of manuscript setting operation- FIG. 12 is a flowchart showing an example of the flow of processing of the document setting operation in the document G transport operation by the control unit 260.

[0080] 12, first, the control unit 260 waits until the document set detection unit 293 is turned on (Sa1: No), and when the document set detection unit 293 is turned on (Sa1: Yes), it drives the tray drive unit 272 to raise the document stacking tray 210 (Sa2). Next, the control unit 260 determines whether the document feed position detection unit 291 is turned on (Sa3), and if it determines that the document feed position detection unit 291 is off (Sa3: No), it proceeds to Sa2. On the other hand, when the control unit 260 determines that the document feed position detection unit 291 is turned on (Sa3: Yes), it stops driving the tray drive unit 272 and stops raising the document stacking tray 210 (Sa4).

[0081] - Example of document reading operation - FIG. 13 is a flowchart showing an example of the process flow of the document reading operation in the document G transport operation by the control unit 260.

[0082] 13, first, the control unit 260 drives the transport drive unit 271 (Sb1), starts transporting the Nth sheet of original G (N is an integer equal to or greater than 1), and reads the image of the original G as image data (Sb3). Next, the control unit 260 turns on the original feed position detection unit 291 (Sb1), starts transporting the Nth sheet of original G (N is an integer equal to or greater than 1), and reads the image of the original G as image data (Sb3).

[0083] Next, the control unit 260 determines whether the document feed position detection unit 291 is on or not (Sb4), and if it determines that the document feed position detection unit 291 is off (Sb4: No), it drives the tray drive unit 272 to raise the document stacking tray 210 (Sb5) and proceeds to Sb4. On the other hand, if the control unit 260 determines that the document feed position detection unit 291 is on (Sb4: Yes), it proceeds to Sb6.

[0084] Next, the control unit 260 determines whether or not a predetermined request has been received (Sb6), and if the predetermined request has not been received (Sb6: No), determines whether or not this is the last document G (Sb7), and if this is not the last document G (Sb7: No), proceeds to Sb2. On the other hand, if this is the last document G (Sb7: Yes), the control unit 260 stops driving the transport drive unit 271 to stop transport of the document G (Sb8).

[0085] Next, the control unit 260 determines whether the lowest position detection unit 292 is on or not (Sb9), and if it determines that the lowest position detection unit 292 is off (Sb9: No), it lowers the document stacking tray 210 (Sb10) and proceeds to Sb9. On the other hand, if the control unit 260 determines that the lowest position detection unit 292 is on (Sb9: Yes), it stops driving the tray drive unit 272 and stops the lowering of the document stacking tray 210 at the lowest position P2 (Sb11).

[0086] On the other hand, when the control unit 260 receives a predetermined request (Sb6: Yes), it stops driving the transport drive unit 271 to stop the transport of the originals G (Sb12), and determines whether the remaining amount of the originals G on the original stacking tray 210 is greater than the reference remaining amount (Sb13). Here, the remaining amount of the originals G is a value obtained by subtracting the number of transported originals G from the initial number of originals G calculated from the lift distance from the lowest position P2 of the original stacking tray 210 to the original feed position P1.

[0087] If the control unit 260 determines that the remaining amount of documents G on the document stacking tray 210 is less than the reference remaining amount (Sb13: No), it lowers the document stacking tray 210 by a predetermined amount (Sb14), stops driving the tray drive unit 272, temporarily stops the lowering of the document stacking tray 210 at the intermediate position P3 (Sb15), and proceeds to Sa1 shown in Figure 12.

[0088] On the other hand, if the control unit 260 determines that the remaining amount of documents G on the document stacking tray 210 is greater than the reference remaining amount (Sb13: Yes), it determines whether the bottom position detection unit 292 is on (Sb16).

[0089] If the control unit 260 determines that the lowest position detection unit 292 is off (Sb16: No), it lowers the document stacking tray 210 (Sb17) and proceeds to Sb16. On the other hand, if the control unit 260 determines that the lowest position detection unit 292 is on (Sb16: Yes), it stops driving the tray drive unit 272, temporarily stops the lowering of the document stacking tray 210 at the lowest position P2 (Sb18), and proceeds to Sa1 shown in FIG.

[0090] The present invention is not limited to the above-described embodiments, but can be embodied in various other forms. Therefore, the embodiments are merely illustrative in all respects and should not be interpreted as limiting. The scope of the present invention is defined by the claims and is not limited in any way by the text of the specification. Furthermore, all modifications and variations that fall within the equivalent scope of the claims are within the scope of the present invention. [Explanation of symbols]

[0091] 100 Image forming device 101 Image forming apparatus main body 102 Image reader 200 Document feeder 200a Document feeder body 200a1 bottom 201 Document transport unit 210 Document loading tray 210a Rotating shaft 211 Tray lifting unit 211a Rotation axis 211b Tray push-up section 211b1 Detected part 220 Manuscript Supply Department 221 Intake roller 222 Supply roller 223 Separation member 224 Supply drive transmission mechanism 225 Support member 225a Detected part 230 Document feeder 240 Document output section 250 Document output tray 260 Control Unit 261 Processing section 262 Storage section 271 Conveyor drive unit 272 Tray drive unit 291 Document feed position detection unit 292 Bottom position detection unit 293 Document set detector 294 First conveyance detection unit 295 Second conveyance detection unit G Manuscript G1 tip G2 Detected part H Conveying direction M1 Intermediate position descending operation mode M2 Bottom position descending operation mode P1 Original feed position P2 Bottom position P3 intermediate position Q Original supply position W width direction X horizontal direction Y depth direction Z vertical direction α Rotation axis β rotation axis

Claims

1. a document loading tray that can be raised and lowered between a document loading position where the document is loaded and a lowest position; a tray lifting unit that lifts and lowers the document stacking tray; a document transport unit that transports the documents loaded on the document loading tray one by one while the tray lifting unit positions the document loading tray at the document loading position; a document set detection unit provided on the document stacking tray for detecting whether the document is set on the document stacking tray; A document feeder comprising: A document feeding device characterized in that, after the document transport unit starts continuous transport of the document on the document loading tray positioned at the document feed position by the tray lifting unit, when a specified request to stop transport of the document is received during the transport of the document, the document transport is stopped and an intermediate position lowering operation is performed by the tray lifting unit to lower the document loading tray by a specified amount from the document feed position to an intermediate position higher than the lowest position.

2. 2. The document feeder according to claim 1, The document feeder is characterized in that the document set detector detects whether or not the document has been set on the document stacking tray located at the intermediate position after the intermediate position lowering operation is performed.

3. 3. The document feeder according to claim 1, A document feeding device characterized in that the specified amount is a range between the position of the document loading tray at which the document set detection unit can detect the document and the position of the document loading tray at which the document can be set by the document loading tray.

4. 4. The document feeder according to claim 1, wherein: The document feeding device is characterized in that, when the document loading tray is lowered, the intermediate position is located above the vertical center position of the maximum detectable distance of the document by the document set detection unit when the leading edge of the document on the document loading tray remains in the document feed position.

5. 5. The document feeder according to claim 1, wherein: The document feeding device is characterized in that the specified request includes at least one of a pre-scan request that requests a pre-scan to read only the images of a portion of a plurality of documents as image data in advance, a document re-setting request that requests the document to be re-set when a transport failure of the document is detected during transport of the document by the document transport unit, and a transport cancellation request that requests the document to be canceled during transport of the document by the document transport unit.

6. 6. The document feeder according to claim 1, a document feeder configured to stop the transport of the originals on the document loading tray positioned at the document feed position by the tray lifting unit after the document transport unit has started continuous transport of the originals on the document loading tray, and when the specified request to stop the transport of the originals is received during the transport of the originals, the document feeder stops the transport of the originals, and when the remaining amount of the originals on the document loading tray is greater than a specified reference remaining amount, performs a lowest position lowering operation to lower the document loading tray from the document feed position to the lowest position without performing the intermediate position lowering operation, and detects whether the originals have been set on the document loading tray positioned at the lowest position by the document set detection unit.

7. 7. An image forming apparatus comprising the document feeder according to claim 1.

Images