JP2006347747A - Document carrying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a document carrying device reducing the occurrence of wrinkles and damage in paper, when developing a folding part of the paper having the folding part. <P>SOLUTION: This document carrying device has a carrying means (a rotary roller 221, and a carrier roller 210) carrying the paper at a predetermined carrying speed, and a folding developing part 226 arranged in a carrying passage of the paper and developing folding of the folding part by contacting with with an overlapping part of the paper having the folding part carried from the upstream side of the carrying passage; and is characterized by switching the carrying speed by the carrying means to a carrying speed slower than the predetermined carrying speed from the predetermined carrying speed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an original conveying apparatus, and more particularly, to an apparatus having a folding and unfolding portion for unfolding a sheet having a folding portion such as a Z-fold original.

  Conventionally, when collating printed matter including paper of different sizes, for example, A4 size and A3 size, the A3 size paper is sometimes folded into a Z shape to make the size of A4 size.

  Here, the folding of the sheet having the folding portion will be described with reference to FIG. 10, taking a Z-shaped folding as an example. FIG. 10 shows a Z-shaped fold, wherein (a) is a perspective view and (b) is a side view. As shown in FIG. 10A, the Z-shaped folding means that a standard sheet, for example, A3 sheet is first folded in half in the longitudinal direction at the first folding part B1, and then the upper sheet is folded in two. Is folded in half by the second folding part B2 so that the end of the paper is on the outside, and as shown in FIG. 10 (b), the side surface is Z-shaped (in the figure, inverted Z-shaped. ) In addition, it includes an overlapping portion of sheets formed by Z-shaped bending.

  On the other hand, there is a case where the printed matter folded in the Z-shape is copied as a document (hereinafter referred to as “Z-folded document”, and a normal document without folding is referred to as “unfolded document”). is there. In such a case, it is necessary for an operator to unfold the Z-folded document and place it on an automatic document feeder to read the document. In the case of a document in which a Z-folded document and an unfolded document are mixed (for example, a document in which A4 size printed matter and A3 are Z-shaped and A4 size are mixed), the operator The Z-folded original had to be found from the original bundle.

  Therefore, a fold unfolding mechanism for unfolding a Z-shaped fold in the document transport path is provided so that even if the document is a mixture of Z-folded documents and unfolded documents, an operator can bother to unfold the Z-folded documents. There is an automatic document feeder that can perform copying without any problem (see, for example, Patent Document 1). In the automatic document feeder described in Patent Document 1, a Z-fold document is developed by a folding and unfolding mechanism. In some cases, the Z-folded document is slowed down so as not to cause wrinkles or breakage (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 5-116828 JP-A-5-124767

  However, the automatic document feeder described in Patent Document 2 cannot identify that the original is a Z-fold original until the overlapping portion reaches the folding and unfolding mechanism, and therefore the overlapping portion reaches the folding and unfolding mechanism. Since the conveyance speed is later lowered, there is a possibility that the overlapping portion contacts the folding and unfolding mechanism before the conveyance speed is lowered, that is, at a high speed, thereby causing wrinkles and breakage.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an original conveying apparatus that reduces the occurrence of wrinkling and breakage of a sheet when a folded portion of a sheet having a folded portion is developed. Is to provide.

  In order to solve the above-mentioned problem, the invention according to claim 1 is provided with a conveying means for conveying a sheet at a predetermined conveying speed, and a folding provided in the sheet conveying path and conveyed from the upstream side of the conveying path. A folding / unfolding portion that unfolds the folding portion in contact with the overlapping portion of the paper having a portion, and the conveyance speed by the conveying means before the folding / unfolding portion contacts the overlapping portion. And a conveyance speed control means for switching to a conveyance speed slower than the predetermined conveyance speed.

  According to a second aspect of the present invention, there is provided a conveyance unit that conveys a sheet at a predetermined conveyance speed, and a folding unit that is provided in the conveyance path of the sheet and is conveyed from an upstream side of the conveyance path. A folding and unfolding portion that unfolds the folding portion in contact with the overlapping portion; and detecting means that detects whether or not the sheet is a sheet having a folding portion, wherein the detection by the detecting means It is characterized in that it is performed before the contact of the developing portion with the overlapping portion of the sheets.

  The invention described in claim 3 is characterized in that the detection means is provided on the upstream side in the transport direction from the folding and unfolding portion.

  According to a fourth aspect of the present invention, when the detecting means detects that the sheet has a folding portion, the conveying speed by the conveying means is set before the folding and unfolding portion contacts the overlapping portion. The apparatus further includes a conveyance speed control means for switching from a predetermined conveyance speed to a conveyance speed slower than the predetermined conveyance speed.

  The invention according to claim 5 is characterized in that the detecting means detects whether or not the folded portion is present by detecting the overlapping portion.

  The invention according to claim 6 is characterized in that the detecting means detects the overlapping portion based on a thickness.

  The invention according to claim 7 is characterized in that the detection means detects the overlapping portion based on the amount of transmitted light.

  The invention according to claim 8 is characterized in that the detecting means detects the overlapping portion by detecting a gap between sheets of the overlapping portion.

  The invention according to claim 9 is characterized in that the detecting means also has a function of detecting double feeding of the paper.

  According to a tenth aspect of the present invention, in the paper, at least one paper edge is positioned outside the overlapping portion, and the conveying means includes a paper edge positioned outside the overlapping portion. It conveys toward the downstream of the said conveyance path, It is characterized by the above-mentioned.

  The invention according to claim 11 is characterized in that the folding and unfolding portion develops the folding of the folding portion by contacting the overlapping portion of the paper folded in a Z-shape.

  According to the document conveying device of the first aspect, since the conveying speed is switched before the folding and unfolding portion comes into contact with the overlapping portion of the sheets, it is possible to reduce the occurrence of wrinkling or breakage of the sheets.

  According to the document conveying device of the second aspect, since it is possible to detect whether or not the sheet has a folding portion before the contact of the folding and unfolding portion with the sheet, the folding portion is unfolded. The sheet can be controlled to reduce the occurrence of wrinkles and breakage.

  Hereinafter, an embodiment of an image forming apparatus including a document conveying device according to the present invention will be described with reference to the drawings.

〔Constitution〕
(Mechanical structure)
FIG. 1 is a cross-sectional configuration diagram of an image forming apparatus according to the present embodiment, and is an example in which a document conveying device is applied to an image forming apparatus. The image forming apparatus 1 includes an operation unit 80, an automatic document feeding device 2 (document conveying device), a document reading unit 3, an image processing unit 7, an image writing unit 4, an image forming unit 5 having a transfer material feeding unit, And a paper feed unit 6.

  Although not shown, the operation unit 80 is provided with a switch, a numeric keypad, a liquid crystal touch panel, and the like, and can input desired image forming conditions such as the number of sheets, scaling, copy density, duplex copying, transfer material size selection, and start. .

  The automatic document feeder 2 detects a document feeding unit 203 having a document placing tray 200, a sheet feeding roller 201, and a separation roller 202, a document d fed from the document feeding unit 203, and a folding unit. A conveyance section 222 (conveyance means) having a document detection sensor S2 for detecting a sheet of paper, a rotation roller 221, and conveyance rollers 210 and 220 that are arranged around the rotation roller 221 and sandwich and convey the rotation roller 221 and the document d. A folding and unfolding portion 226 that is a folding and unfolding mechanism portion having a unfolding guide 225 for unfolding a sheet having a folding portion between the transport roller 210 and the transport roller 220, a document reading position 230, and a reverse A document reversing unit 241 having a roller 240, a paper discharge roller 250, and a paper discharge tray 260, and a document placement tray 200 of the document feed unit 203. The document placed d are sequentially conveyed to the document reading position 230, reads the document d, discharged to the discharge tray 260. In the case of a sheet having a fold, the sheet is conveyed and read while unfolding.

  Hereinafter, in the present embodiment, the document detection sensor S2 uses a Z-folded document folded in a Z shape (hereinafter referred to as “Z-folded document dz” in order to distinguish a Z-fold change from other documents). An example in which the folding and unfolding unit 226 unfolds the Z-folded document dz will be described.

  When reading both sides of the document, after reading the first surface (front surface) of the document, the document is reversed by the document reversing unit 241, and the document is conveyed again to the document reading position 230. After the second side (back side) is read, the sheet is discharged to the discharge tray 260.

  The document reading unit 3 includes a platen glass 300 that performs exposure for reading while moving the document, a platen glass 301 that performs exposure for reading by placing the document, a light source 302, mirrors 303, 304, and 305, and imaging optics. It comprises a system 306, an image pickup device 307 comprising a CCD, and an optical drive system. In the document reading unit 3, light is emitted from the light source 302 formed of a xenon lamp to the document d on the platen glass 300 and 301, and the reflected light is guided to the mirrors 303, 304, and 305 and the CCD is formed via the imaging optical system 306. The image is captured by the image sensor 307.

  As a result, an image of the document d is formed on the light receiving surface of the CCD image sensor 307. Here, when an original is placed on the platen glass 301, the optical image is read by the CCD image sensor 307 as the optical drive system scans the original along the platen glass 301. When the automatic document feeder 2 automatically feeds a document, the CCD image sensor 307 transports the document while the light source 302 and mirrors 303, 304, and 305 are fixed under the platen glass 300. The image is loaded. The image data read by the document reading unit 3 is stored in the storage unit 8 after predetermined image processing is performed by the image processing unit 7.

  The paper feed unit 6 is provided with paper feed trays 41A to 41D, and transfer materials P of various sizes are stored in the paper feed trays 41A to 41D. A transfer material having a size automatically selected based on information from the first or second document size detection sensors S1 and S2 is fed out from any of the paper feed trays 41A to 41D and fed to the image forming unit 5.

  When the image signal is input to the image writing unit 4, the image forming unit 5 starts an image recording operation. That is, the photosensitive drum 31 rotates clockwise as indicated by an arrow, and after being neutralized, the electric charge is given by the charger 32. Therefore, the image writing unit 4 applies a laser beam to the photosensitive drum 31 on the photosensitive drum 31. An electrostatic latent image corresponding to the image of the document d is formed. Thereafter, the electrostatic latent image on the photosensitive drum 31 is reversely developed by the developer of the developing device 33 to become a visible toner image.

  On the other hand, the transfer material P having a size automatically selected according to the document size is unloaded from the sheet feeding cassettes 41 </ b> A to 41 </ b> D loaded in the sheet feeding unit 6 one by one by the unloading rollers 42 </ b> A to 42 </ b> D. Then, the paper is fed toward the image transfer section 34. The fed transfer material P is sent onto the photosensitive drum 31 by a conveying roller 44 that operates in synchronization with the toner image on the photosensitive drum 31. A toner image on the photoconductive drum 31 is transferred to the transfer material P by the action of the transfer unit 34, separated from the photoconductive drum 31, and then sent to the fixing device 37 through the conveyance belt 45 to be melted. After fixing, the paper is discharged onto a tray 54 outside the apparatus by a paper discharge roller 38.

  The photosensitive drum 31 continues to rotate, and toner remaining without being transferred to the surface of the photosensitive drum 31 is removed and cleaned by the cleaning device 39, and after being discharged again, the charger 32 is given charge like Lee, The next image forming process starts.

  The paper feeding unit 6 includes a reversing unit 46, and the fixed transfer material P is conveyed downward through a guide 47 and enters the reversing unit 46. Next, the transfer material P contained in the reversing unit 46 is again fed out by the reversing roller 48 and is sent again to the image forming unit 5 through the reversing conveyance path 49 to perform the next image formation.

(Automatic document feeder)
The automatic document feeder 2 will be described in more detail.

  The document placement tray 200 of the document feeder 203 is provided with a document presence / absence detection sensor S0 for detecting the presence / absence of the document d and a document size detection sensor S1 for detecting the document size in the loaded state. . The document size detection sensor S1 includes a document width detection sensor S11 for detecting the width of the document in a direction perpendicular to the transport direction, and document length detection sensors S12a to S12c (for detecting the length of the document in the transport direction). Hereinafter, the document length detection sensor S12 may be collectively referred to as “,” and the document size placed on the document placement tray 200 is detected in a loaded state. A paper feed roller 201 and a separation roller 202 are sequentially arranged on the downstream side of the document placing tray 200. The paper feed roller 201 rotates by receiving a driving force of a paper feeding motor M1 (not shown) via a driving force transmission means (not shown) and feeds a document d. The separation roller 202 is disposed to face the separation pad 202a, and separates and feeds only one document d so that a plurality of documents d are not sent out.

  Further, downstream of the document feeding unit 203, a drum-shaped rotating roller 221 and a conveying roller 210 and a conveying roller 220 are disposed around the drum-shaped rotating roller 221. The conveying roller 210 and the conveying roller 220 are not illustrated. The document d is pressed together with the rotation roller 221 by being pressed by the urging means, and the rotation roller 221 receives the driving force of the transport motor M2 (not shown) via a driving force transmission means (not shown) and rotates to read the document d. Transport to position 230. Further, a document detection sensor S2 is provided between the separation roller 202 and the transport roller 210, and a paper discharge sensor S3 is provided on the upstream side of the paper discharge roller 250 in the document transport direction. Detect the edge. Based on this detection result, the operation of each part of the automatic document feeder 2 is controlled. Further, the document detection sensor S2 detects a Z-folded document dz, and when it is detected as a Z-folded document dz, the operation is controlled (details will be described later) according to the Z-folded document dz.

  The document d that has been read is discharged to the discharge tray 260 by a discharge roller 250 that rotates by receiving a driving force of a conveyance motor M2 (not shown) via a driving force transmission means (not shown). In the case of a double-sided document, a reversing guide solenoid SOL2 (not shown) is operated, the conveying path is switched by the reversing guide 242, the document d is sent to the document reversing unit 241, the switchback is reversed by the reversing roller 240, and the conveying roller The document d is again conveyed to the document reading position 230 by the conveyance roller 210, and after the back side of the document is read, the document d is discharged to the sheet discharge tray 260.

  Here, folding and unfolding of the Z-folded document dz in the automatic document feeder 2 will be described.

  First, the folding / unfolding portion 226 will be described with reference to FIG. As shown in FIG. 2, the folding and unfolding portion 226 includes a unfolding guide 225 and a folding housing portion 227. A document guide surface 228 and a Z-fold guide surface 229 are formed on the unfolding guide 225, and are arranged so that the outer periphery of the rotation roller 221 and the document guide surface 228 face each other, and a fulcrum (in this example, the axis center of the transport roller 220). Is operated by a deployment guide solenoid SOL1 (not shown) in the direction of the arrow centered on the center, and the distal end portion a of the deployment guide 225 is in an open state with a gap between the rotation roller 221 or the rotation roller 221 and Proximity close.

  Next, the Z-fold original dz will be described. As described in [Prior Art], as shown in FIG. 10A, the Z-fold original dz is first folded, for example, in half in the longitudinal direction at the first folding portion B1 with the A3 sheet, and then into two. The folded upper sheet is folded in half at the second folding section B2 so that the end of the sheet is on the outside. The Z-folded document dz is placed on the document placing tray 200 so that the first folding part B1 is on the upstream side in the document transport direction, and outside the overlapping part on the side opposite to the first folding part B1. It is conveyed with the end b positioned at the front side (that is, the tip). Therefore, the second folding part B2 is located approximately in the middle of the conveyance direction of the Z-folded document dz. Further, as shown in FIG. 10A, the surface including the front end b and the first fold B1 is the base surface dza, and the surfaces formed by the first fold, that is, the first fold B1 and the second fold B2. The surface including the first folding surface dzb, the surface formed by the next folding, that is, the surface including the end c on the opposite side of the front end b and the second folding portion B2, and the second folding surface dzc. To do. Further, a portion where the base surface dza, the first folding surface dzb, and the second folding surface dzc overlap, that is, an overlapping portion of the paper is referred to as an overlapping portion.

  Next, folding and unfolding of the Z-fold original dz will be described with reference to FIG. However, in FIG. 3, the conveyance roller 220 is omitted so as not to be complicated.

  As described above, when the Z-folded document dz is conveyed by the rotation roller 221 and the conveyance roller 210, first, the document guide surface 228 of the unfolding guide 225 is opposed to the rotation roller 221 as shown in FIG. While maintaining the open state, the leading end of the Z-fold original dz is guided. After that, when the unfolding guide 225 is brought close to the rotating roller 221 and the Z-folded document dz is further conveyed, as shown in FIG. 3B, the first folding surface dzb and the second folding portion B2 are set at the head. The second fold surface dzc is guided by the Z fold guide surface 229 and is accommodated in the fold accommodating portion 227 (the rotation roller 221 and the conveyance roller 210 are separated from each other, but in order to make the fold visible). In fact, as in FIG. 3A, the rotating roller 221 and the conveying roller 210 are close enough to sandwich and convey the Z-folded document dz. Further, when the Z-fold original dz is conveyed, as shown in FIG. 3C, the first fold B1 hits the development guide 225, the first fold B1 is developed, and the first fold surface dzb is the original. By being introduced to the guide surface 228 side and further transported (not shown), the second folding portion B2 is developed and the second folding surface dzc is introduced between the document guide surface 228 and the rotation roller 221.

[Control configuration]
Next, the control configuration of this embodiment will be described. FIG. 4 is a block diagram showing a control configuration of the automatic document feeder 2.

  The operation unit 80 has a function as an input unit for performing various inputs such as the number of documents, the type, and the density. Information input from the operation unit 80 is input to the control unit 20 as various setting information. Further, the control unit 20 includes a document presence / absence detection sensor S0, a document width detection sensor S11 constituting the document size detection sensor S1, and three document length detection sensors S12 (S12a to S12c), and an example of the detection unit of the present invention. Detection information from the document detection sensor S2 and the discharge sensor S3 is input.

  The control unit 20 controls the paper feed motor M1, the transport motor M2, the unfolding guide solenoid SOL1, and the reverse guide guide solenoid SOL2 based on these detection information and setting information. Further, the control unit 20 measures time (t1, t2, t3, t4, which will be described later) with reference to a timer (not shown), and supplies it at a predetermined time (H1, H2,. The paper motor M1, the conveyance motor M2, the unfolding guide solenoid SOL1, and the reverse guide guide solenoid SOL2 may be controlled. Further, the control unit 20 has a function as an identification unit for identifying the unfolded document d or the Z-folded document dz based on the detection result of the document detection sensor S2, and determines the document conveyance speed based on the identification result. It has a function as a conveyance speed control means of the present invention to control. For this purpose, the control means 20 stores a CPU (not shown), various programs such as a control program for the entire apparatus and various data necessary for executing the program, and executes various programs. And a system memory (not shown) constituting the work area. The control unit 20 controls each unit of the image forming apparatus (not shown).

  The operation unit 80 includes, for example, a touch panel that accepts operations and a display that includes an LCD that displays patterns and characters, and can perform various inputs by pressing the touch panel at positions displayed on the LCD. It is composed of.

  The document presence / absence detection sensor S0, the document width detection sensor S11, the three document length detection sensors S12 (S12a to S12c), and the discharge sensor S3 can be configured using a photo sensor or the like.

  The document detection sensor S2 detects the double feed of the document and the Z-folded document dz in addition to the presence / absence of the document, and the number of sheets (Z, 0, 1, 2 and 3) (Z In the case of a folded document, a document whose output value varies depending on the number of overlapping portions). That is, the control means 20 can detect the number of documents based on the output value of the document detection sensor S2. In this example, when the document detection sensor S2 has an output value corresponding to the number of documents being two, it is the output value corresponding to the detection of double feeding of documents and being three. Is detected that the original is a Z-fold original dz. For example, a document detection sensor S2 is used in which output values corresponding to the absence of documents, one sheet, two sheets, and three sheets change stepwise as shown in FIG. As such a sensor, for example, a contact is brought close to the surface of a document, and the thickness is detected from an output value that changes in accordance with the thickness (number of sheets) by changing the position of the contact. Alternatively, it is possible to use a device in which a light source and a light receiving element are arranged to face each other with a document interposed therebetween, and the number of sheets is detected from an output value that changes according to the amount of transmitted light. Also, an ultrasonic transmitter and an ultrasonic receiver are provided facing each other with a document interposed therebetween, and the number of gaps is detected by analyzing the output signal of the ultrasonic receiver, For example, it is possible to use one that detects one sheet if the gap is 0, two sheets (double feed) if the gap is 1, and three sheets (Z-fold original) if the gap is 3. Therefore, the control unit 20 identifies the unfolded document d, the Z-folded document dz, and the document double feed based on the output value (detection result) of the document detection sensor S2.

  The paper feed motor M1 and the transport motor M2 are pulse motors, and the unfolding guide solenoid SOL1 and the reverse guide guide solenoid SOL2 are DC solenoids.

[Mode of operation]
Next, an operation mode in the image forming apparatus having the automatic document feeder 2 configured as described above will be described with reference to FIGS. FIG. 6 is a flowchart showing an operation mode in the control unit 20 of the image forming apparatus, and FIG. 7 shows each sensor and each driving unit in the case of an unfolded document d (hereinafter simply referred to as document d). FIG. 8 is a timing chart for each sensor and each driving unit in the case of a Z-fold original dz.

  Further, FIG. 9 shows the document reading position 230 on the conveyance path, the detection position of the document detection sensor S2 on the conveyance path, the document clamping position by the conveyance roller 210, and the position of the front end of the development guide 225 on the conveyance roller 210 side, respectively. Shown as C. Here, the distance on the conveyance path from the detection position A of the document detection sensor S2 to the document clamping position B by the conveyance roller 210 is L1, and the conveyance roller 210 side tip position C of the development guide 225 from the document clamping position B by the conveyance roller 210. L2 is the distance on the conveyance path to the original document reading position 230, and L1, L2, and L3 are used in the following description. .

(In the case of manuscript d)
First, the document d will be described. As shown in FIGS. 6 and 7, first, when a document is placed on the document placing tray 200, the presence / absence of the document is detected by the document presence / absence detection sensor S0, and, for example, reading of the document is started from the operation unit 80. When an instruction is input, the control unit 20 starts driving the paper feed motor M1 (step ST101 in FIG. 6, hereinafter abbreviated as ST101. The same applies to other steps). Then, the document d is conveyed by the paper feed roller 201, and when the leading edge of the document d passes the document detection sensor S2, the document detection sensor S2 detects the leading edge of the document d (ST102, Y). Then, when the output value of the document detection sensor S2 is an output value indicating two sheets, the control unit 20 identifies double feed (ST103, Y), and performs double feed error processing. The double feed error process is, for example, canceling the conveyance and notifying that double feed has occurred. By the way, when the document d does not reach the document detection sensor S2 due to a paper jam or the like, a predetermined time is set as an unsent error. However, the unsent error processing is omitted because the figure and the explanation become complicated. Similarly, the unsent error processing based on the other sensor detection results below was also omitted.

  If the output value of the document detection sensor S2 is an output value indicating one sheet (ST103, N), the control unit 20 starts measuring t1 (ST104) and starts driving the transport motor M2 (ST105). The rotating roller 221 rotates. Here, the conveyance motor M2 is driven such that the conveyance speed (hereinafter, simply referred to as a conveyance speed) at the rotation roller 221, the conveyance rollers 210 and 220, and the paper discharge roller 250 is V1. To do. This is obtained from the diameter of the rotating roller 221, the diameter of the paper discharge roller 250, the reduction ratio of the drive transmission means, and the like, and is set in advance at the time of factory shipment or installation of the image forming apparatus.

  Then, the control unit 20 stops the paper feed motor M1 when t1 becomes H1 (ST106). Here, H1 will be described. The paper feed motor M1 must stop after at least the front end of the document d reaches the document clamping position B by the transport roller 210. Therefore, H1 is a time obtained by adding a design margin to the time for transporting the distance L1 at least at the transport speed V1.

  Further, when t1 becomes H2, the control unit 20 turns on the deployment guide solenoid SOL1, and brings the deployment guide 225 into the proximity state with the rotating roller 221 (ST107). Here, H2 will be described. Similar to H1, H2 is at least a distance (L1 + L2) at the conveyance speed V1 so that at least the leading edge of the document d reaches and is guided by the document guide surface 228 of the document guide 225 before the deployment guide is brought into the proximity state. This is obtained by adding a design margin to the transport time.

  Then, the control unit 20 identifies whether or not it is a Z-folded document dz from the output result of the document detection sensor S2, but when it is not a Z-folded document dz (ST108, N), when t1 becomes H3 (ST109). Y), the document reading unit 3 is controlled to start reading (ST110). Here, H3 will be described. Since reading is started when the leading edge of the document d reaches the document reading position 230, H3 is a time for transporting the distance (L1 + L2 + L3) at the transport speed V1 as in H1. However, H3 is adjusted according to the reading start position of the document d.

  Further, when the document detection sensor S2 is turned off (ST111, Y), the control unit 20 starts measuring t2 (ST112), turns off the deployment guide solenoid SOL1, and opens the deployment guide (ST121). Further, the control unit 20 controls the document reading unit 3 so as to end the reading when t2 becomes H4 (ST122). Here, H4 will be described. When the trailing edge of the document d reaches the document reading position 230, the reading is terminated. Therefore, H4 is a time for transporting the distance (L1 + L2 + L3) at the transport speed V1 as in H3. However, H4 is adjusted according to the reading range of the document d, similarly to H3.

  When the trailing edge of the document d passes the paper discharge sensor S3 (hereinafter, the paper discharge sensor S3 is turned off) (ST123, Y), the control unit 20 turns the Z-fold flag OFF (ST124) (Z-fold flag). Is turned on in the case of the Z-folded original dz and remains OFF in the case of the original d.) The measurement of t3 is started (ST125), and when t3 becomes H5, the transport motor M2 is turned on. Stop (ST126). Although not shown, H5 is a time in which a design margin is added to the time for transporting from the paper discharge sensor S3 to the paper discharge roller 250 at least at the transport speed V1.

(For Z-folded document dz)
Next, the case of the Z-folded original dz will be described. In the case similar to the case of the original d described above, detailed description will be omitted as much as possible, and different points will be mainly described. The timing chart will be described with reference to FIG.

  As shown in FIGS. 6 and 8, first, the Z-folded document dz is placed on the document placing tray 200, and the control unit 20 starts driving the paper feed motor M1 as in the case of the document d. (ST101). Then, the document dz is conveyed, the document detection sensor S2 detects the leading edge of the Z-folded document dz (ST102, Y), and when the output value of the document detection sensor S2 is an output value indicating two sheets, double feeding is performed. Identify (ST103, Y) and perform double feed error processing.

  If the output value of the document detection sensor S2 is an output value indicating one sheet (ST103, N), the control unit 20 starts measuring t1 (ST104) and starts driving the transport motor M2 (ST105). The rotating roller 221 is rotated. Here, the transport motor M2 is driven so that the transport speed becomes V1.

  Next, the control unit 20 stops the paper feed motor M1 when t1 becomes H1 (ST106). Further, when t1 becomes H2, the deployment guide solenoid SOL1 is turned on (ST107).

  Then, the control unit 20 identifies whether the document is a Z-folded document dz from the output result of the document detection sensor S2, but if an output value indicating two sheets is detected, it is identified as a Z-folded document dz (ST108, Y ), The control unit 20 turns on the Z-fold flag (ST113). Furthermore, measurement of t4 is started (ST114), and H3 is reset to H3 ′ (ST115). Here, H3 ′ is used because it is necessary to consider the change in the conveyance speed from V1 to V2 performed in the next ST116 for H3. For example, if the speed is changed at an intermediate position between the document clamping position B by the transport roller 210 and the front end position C of the unfolding guide 225 on the transport roller 210 side, H3 ′ transports the distance (L1 + L2 / 2) at the transport speed V1. And the time for transporting the distance (L2 / 2 + L3) at the transport speed V2.

  Then, when t4 becomes H6, the control unit 20 changes the driving of the conveyance motor M2 so that the conveyance speed becomes V2 slower than V1 (ST116). In ST108, the Z-folded document dz is identified when the second folded part B2 of the Z-folded document dz passes the document detection sensor S2, and H6 is the second folded part of the document dz at the transport speed V1. The time from B2 passing through the document detection sensor S2 to before reaching the leading end position C on the conveyance roller 210 side of the unfolding guide 225 is shorter than the time for conveying the distance (L1 + L2) at the conveyance speed V1. Therefore, for example, if the conveyance speed is changed to V2 in the state of FIG. 3A, before the overlapping portion of the Z-folded document dz reaches the front end position C on the conveyance roller 210 side of the unfolding guide 225, in other words, the second. Since the conveyance speed is V2 before the folding portion B2 reaches the front end position C of the development guide 225 on the conveyance roller 210 side, even if the second folding portion B2 hits the development guide 225, the speed is higher than V1. Since it is slow V2, it is possible to prevent the Z-fold original dz from being wrinkled or damaged.

  Next, the control unit 20 controls the document reading unit 3 to start reading when t1 becomes H3 ′ (ST117).

  When the Z-folded document dz is further conveyed at V2, the trailing edge of the Z-folded document dz passes through the document detection sensor S2, and the document detection sensor S2 is turned off (ST118, Y), the control unit 20 measures t2. Start (ST119).

  Furthermore, the Z-fold original dz is conveyed at V2, and the Z-fold original dz is unfolded as shown in FIGS. Then, when t4 becomes H7, the control unit 20 conveys, for example, when the rear end portion of the developed Z-folded document dz passes through the front end portion of the unfolded guide 225 on the conveying roller 210 side and is introduced to the document guide surface 228 side. The drive of the motor M2 is changed so that the conveyance speed is changed from V2 to V1 (ST120), the deployment guide solenoid SOL1 is turned off, and the deployment guide is opened (ST121). H7 is H6, and the conveyance speed is V2 after H6, the time until the first folding portion B1 of the document dz reaches the leading edge position C on the conveyance roller 210 side of the unfolding guide 225, and the conveyance speed is V2. This is the sum of the transport times of the transport direction length of the surface dzb and the transport direction length of the second folding surface dzc. In addition, even when folding is expanded as shown in FIGS. 3B and 3C, the Z-folded document dz is conveyed at V2 which is slower than V1, so that wrinkles and damage do not occur.

  The control unit 20 controls the document reading unit 3 so as to end the reading when t2 becomes H4 ′ (ST122). When the rear end of the Z-folded document dz after being developed reaches the document reading position 230, the reading is finished. H4 ′ takes the length of the first folding surface dzb and the conveyance direction length of the second folding surface dzc and the conveyance at the conveyance speed V2 into H4 in the same manner as in H3 ′.

  When the trailing end of the developed document dz passes through the paper discharge sensor S3 (hereinafter, the paper discharge sensor S3 is turned off) (ST123, Y), the control unit 20 starts measuring t3 (ST125). ) When t3 becomes H5, the transport motor M2 is stopped (ST126).

  Further, since the document conveyed as described above is detected by the document detection sensor S2 as the unfolded document d or the Z-folded document dz, and operates according to the detection result, the document without folding is detected. Even in the case of a document bundle in which d and the Z-folded document dz are mixed, a complicated operation such as separation of each document is not required.

  Further, although the detection unit for the unfolded document d or the Z-folded document dz in the control unit 20 has been described as the document detection sensor S2, for example, the size of the document, the Z-folded document dz, etc. can be selected from the operation unit 80. The control unit 20 has a function as a detection unit that performs input and detects the input, identifies the unfolded document d or the Z-folded document dz, and the control unit 20 starts driving of the paper feed motor M1, that is, feeds It is also possible to control so that the conveyance speed is changed from V1 to V2 before the second folding portion B2 reaches the front end portion of the development guide 225 on the conveyance roller 210 side in the time from the start of the paper. Further, even in the case of a document bundle in which an original document d and a Z-fold original document dz are mixed, an unfolded original document d or a Z-fold original document dz is input from the operation unit 80 for each page. It is possible to control based on.

1 is a cross-sectional view illustrating a schematic mechanical configuration of an image forming apparatus according to an embodiment. FIG. 3 is a diagram for explaining a folding and unfolding unit of the automatic document feeder of the image forming apparatus according to the present embodiment. It is a figure for demonstrating folding expansion | deployment of the Z-fold original in a folding expansion | deployment part. 2 is a block diagram illustrating a control configuration of the image forming apparatus according to the exemplary embodiment. FIG. It is a graph which shows an example of the output value of a document size detection sensor. 6 is a flowchart illustrating an example of an operation mode in a control unit of the image forming apparatus according to the exemplary embodiment. 6 is a timing chart illustrating an example of an operation mode in the case of an unfolded document. It is a timing chart which shows an example of the operation | movement aspect in the case of a Z-fold original. It is a figure for demonstrating the distance from a document detection sensor to a document reading position. It is a figure for demonstrating a Z-fold original.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Automatic document feeder 3 Document reading part 4 Image writing part 5 Image forming part 6 Paper feed part 7 Image processing part 80 Operation part,
200 Document Placement Tray 203 Document Feeding Unit 222 Conveying Unit 226 Folding and Unfolding Unit 225 Unfolding Guide 230 Document Reading Position 241 Document Reversing Unit 250 Paper Discharge Roller 260 Paper Discharge Tray M1 Paper Feed Motor M2 Carrying Motor S0 Document Presence Detection Sensor S1 Document Size detection sensor S2 Document detection sensor S3 Paper discharge sensor SOL1 Deployment guide solenoid SOL2 Reverse guide solenoid

Claims (11)

Conveying means for conveying the paper at a predetermined conveying speed;
A folding and unfolding portion that is provided in the conveyance path of the sheet and that unfolds the folding portion in contact with an overlapping portion of the sheet having a folding portion that is conveyed from the upstream side of the conveyance path;
A conveyance speed control means for switching the conveyance speed by the conveyance means from the predetermined conveyance speed to a conveyance speed slower than the predetermined conveyance speed before the folding and unfolding portion comes into contact with the overlapping portion, Document transport device. Conveying means for conveying the paper at a predetermined conveying speed;
A folding and unfolding portion that is provided in the conveyance path of the sheet and that unfolds the folding portion in contact with an overlapping portion of the sheet having a folding portion that is conveyed from the upstream side of the conveyance path;
Detecting means for detecting whether or not the sheet has a folded portion;
The document conveying device is characterized in that the detection by the detecting means is performed before the contact of the folding and unfolding portion with the overlapping portion of the paper.   The document conveying apparatus according to claim 2, wherein the detection unit is provided upstream of the folding and unfolding portion in the conveying direction.   When the detection unit detects that the sheet has a folding portion, the conveyance speed of the conveyance unit is changed from the predetermined conveyance speed to the predetermined conveyance speed before the folding and unfolding portion contacts the overlapping portion. 4. The document conveying apparatus according to claim 2, further comprising conveying speed control means for switching to a slower conveying speed.   5. The document conveying device according to claim 2, wherein the detection unit detects whether or not the folded portion is present by detecting the overlapping portion. 6.   The document conveying apparatus according to claim 5, wherein the detecting unit detects the overlapping portion based on a thickness.   The document conveying apparatus according to claim 5, wherein the detection unit detects the overlapping portion based on a transmitted light amount.   The document conveying apparatus according to claim 5, wherein the detecting unit detects the overlapping portion by detecting a gap between sheets of the overlapping portion.   9. The document conveying device according to claim 2, wherein the detecting unit also has a function of detecting double feeding of the paper. The paper has at least one paper edge located outside the overlapping portion,
10. The transport device according to claim 1, wherein the transport unit transports the paper toward the downstream side of the transport path with a paper end positioned outside the overlapping portion. 11. Document transport device. The said folding expansion | deployment part contacts the said overlapping part of the said paper folded in Z shape, and expand | folds the folding of the said folding part, It is any one of Claim 1 thru | or 10 characterized by the above-mentioned. Document transport device.

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