JP6565346B2 - Document conveying apparatus, image reading apparatus, and image forming apparatus - Google Patents

Description

  The present invention relates to an original conveying apparatus, an image reading apparatus, and an image forming apparatus.

2. Description of the Related Art Conventionally, in an image reading apparatus provided in a digital copying machine, a printer, a facsimile machine, etc., an automatic document feeder (hereinafter referred to as ADF) for conveying a document to an image reading unit (scanner unit) of the image reading device. The one with is known.
As one of the image reading methods in the image reading apparatus provided with the ADF, the image reading means is fixed at a predetermined position below the platen glass provided in the image reading apparatus, and the image reading means is fixed above the image reading means. A method of reading an image by moving a document one by one at a speed (hereinafter referred to as “scanning reading”) is known.

Adopting the above-mentioned flow reading eliminates the hassle of setting a document on the platen glass and shortens the time required to replace the document. Productivity and productivity can be greatly improved.
In the flow-reading, the originals are conveyed one by one from the original tray to the separation unit and separated by the separation unit, and then the skew is corrected by the registration unit. Then, the sheet is conveyed to a reading position above the fixed image reading unit at a predetermined timing.

  Incidentally, many users of the image reading apparatus use a binder or a document storage folder when storing a document original. Each binder and document storage folder has an appropriate paper size. If you want to store paper that is one size larger than the paper size at the same time, the document may be Z-folded to match the paper size. . Here, the Z-folded document is a document that is folded back so that the surface of the document overlaps the surface of the document at half of the longitudinal direction. It is a document that has been folded back so as to overlap. When the document is Z-folded, the length in the longitudinal direction is ½ of the size before folding, so the paper size is reduced by one. For example, when an A3 size document is Z-folded, it becomes an A4 size document, and when a B4 size document is Z-folded, it becomes a B5 size document.

  In general, when reading the Z-folded original, the user sets the original on the original tray with the folded portion opened. On the other hand, you can set a Z-folded document without opening it, or you can set it with a fold mark that is not fully opened, or set it on a document tray by overlooking that it is a bundle of documents containing a Z-folded document. The case where it does is also considered. If you try to transport a Z-folded document with the folding part not fully open, the document will hit the pickup roller, or it will not be smoothly transported by the pickup roller, resulting in wrinkles and deviations in the folds of the document. Sometimes. Alternatively, the original may be skewed and a jam may occur, which may damage the original.

Therefore, conventionally, for example, a technique for preventing the occurrence of a feeding failure by providing a special mechanism that can open a folded portion of a Z-folded document being conveyed is disclosed (for example, see Patent Document 1). ).
In addition, a determination unit that determines whether or not a sheet stacked on the sheet stacking unit is a Z-folded sheet having a Z-folded portion. A technique for guiding a Z-folded portion by means is disclosed (for example, see Patent Document 2).

Japanese Patent Laid-Open No. 5-116795 JP 2007-326709 A

  However, in the above conventional techniques, when a mixed document including a Z-folded document is placed on the document tray, it is assumed that a Z-fold is formed on the front side, and a Z-fold is formed on the back side. However, there is a problem that the Z-folded portion cannot be developed when the is formed, causing a conveyance failure and impairing productivity and convenience. In particular, in recent years, due to the fact that double-sided printing is frequently used for copying, the number of cases where Z-folding is formed on the back side is increasing, and countermeasures are required.

  The present invention relates to a document conveying apparatus and an image reading apparatus capable of improving the productivity and convenience by suppressing the occurrence of a conveyance failure regardless of whether the Z-fold is formed on either side of the document. An object of the present invention is to provide an image forming apparatus.

The invention described in claim 1 has been made to achieve the above object,
In a document transport device that transports a document placed on a document tray,
A Z-fold detection unit that detects whether the document is Z-folded and whether the Z-fold direction is upward or downward ;
A Z-fold unfolding section for unfolding a Z-fold portion of the document in which the Z-fold is detected by the Z-fold detection section;
A drive control unit that controls the driving of the Z-fold unfolding unit based on the Z-fold direction detected by the Z-fold detection unit;
Equipped with a,
The Z-fold unfolding part is
An upper presser member that is provided on the upper side of the transport path and is provided with a material having a property of imparting transport resistance to the lower surface, and is movable in the vertical direction;
A lower roller that is disposed at a position facing the upper pressing member across the document to be conveyed, rotates about an axis orthogonal to the conveying direction, and is movable in the vertical direction;
A lower presser member that is provided on the lower side of the transport path, is provided with a material having a property of imparting transport resistance to the upper surface, and is movable in the vertical direction;
An upper roller that is disposed at a position facing the lower pressing member across the document to be conveyed, rotates about an axis perpendicular to the conveying direction, and is movable in the vertical direction;
With
When the Z-fold is upward when the drive control unit expands the Z-fold portion, the Z-fold portion is sandwiched between the upper pressing member and the lower roller and the Z-fold is downward. Is characterized in that the Z-folded portion is clamped by the lower pressing member and the upper roller .
The invention described in claim 2
In a document transport device that transports a document placed on a document tray,
A Z-fold detection unit that detects whether the document is Z-folded and whether the Z-fold direction is upward or downward;
A Z-fold unfolding section for unfolding a Z-fold portion of the document in which the Z-fold is detected by the Z-fold detection section;
A drive control unit that controls the driving of the Z-fold unfolding unit based on the Z-fold direction detected by the Z-fold detection unit;
With
The Z folding and unfolding portion is disposed at a position facing the document to be conveyed, and includes a pair of rollers that rotate about an axis perpendicular to the conveyance direction and move in the vertical direction.
When the Z-folded portion is unfolded, the drive control unit sandwiches the Z-folded portion by the pair of rollers, and rotates the roller on the surface side of the pair of rollers on which the Z-fold is formed. It is characterized by being stopped.
The invention according to claim 3
In a document transport device that transports a document placed on a document tray,
A Z-fold detection unit that detects whether the document is Z-folded and whether the Z-fold direction is upward or downward;
A Z-fold unfolding section for unfolding a Z-fold portion of the document in which the Z-fold is detected by the Z-fold detection section;
A drive control unit that controls the driving of the Z-fold unfolding unit based on the Z-fold direction detected by the Z-fold detection unit;
With
The Z folding and unfolding portion is provided at a position facing the document to be conveyed, and includes a pair of claw members that can rotate up and down around an axis that fixes the downstream end in the conveyance direction,
The drive control unit rotates the upper claw member downward and the lower claw member upward when unfolding the Z-folded portion,
When the Z-folded portion is downward, the pair of claw members are rotated to a position above the case where the Z-fold is upward,
The pair of claw members sandwich the downstream side in the transport direction from the Z-folded portion.

According to a fourth aspect of the present invention, in the document feeder according to any one of the first to third aspects,
A paper thickness detector for detecting the paper thickness of the original;
The Z-fold detection unit determines that the Z-fold is upward and determines a change in the paper thickness when it is determined that the change rate of the paper thickness detected by the paper thickness detection unit is equal to or greater than the first threshold. When it is determined that the rate is greater than or equal to a second threshold lower than the first threshold and less than the first threshold, the Z-fold is determined to be downward.

The invention according to claim 5 is the document conveying apparatus according to claim 4 ,
A distance calculating unit that calculates a distance to the Z-folded portion of the document based on the transport time of the document and the change in the paper thickness;
The drive control unit controls driving of the Z-fold developing unit based on the distance to the Z-fold portion calculated by the distance calculation unit.

According to a sixth aspect of the present invention, in the document conveying device according to the fourth or fifth aspect ,
A paper type detection unit that detects the paper type of the document based on the paper thickness detected by the paper thickness detection unit;
The drive control unit controls driving of the Z-fold developing unit based on the paper type detected by the paper type detection unit.

According to a seventh aspect of the present invention, in the document conveying device according to any one of the first to third aspects,
A contact detection unit for detecting a contact pattern with the document;
The Z-fold detection unit detects presence / absence of Z-folding and Z-folding direction of the document based on a contact pattern with the document detected by the contact detection unit.

The invention according to claim 8 is the document conveying apparatus according to claim 1 or 2 ,
The Z-fold developing portion is provided with a pressure detection unit that detects a pressure applied to the document by the Z-fold developing portion when the Z-fold portion is expanded.
The drive control unit controls driving of the Z-fold developing unit based on a change in pressure detected by the pressure detection unit.

The invention according to claim 9 is the document conveying apparatus according to any one of claims 1 to 8 ,
Based on the direction of the Z-fold detected by the Z-fold detection unit , the original reaches the transport roller disposed downstream in the transport direction from the Z-fold unfolding unit before the Z-fold portion has been unfolded. , characterized in that it comprises a conveyance control unit for controlling an at least one of the transport speed of the drive torque and the document of the conveying roller.

The invention according to claim 10 is:
In the image reading device,
An image reading unit for reading an image of a document;
The document conveying device according to any one of claims 1 to 9 , wherein the document placed on a document tray is conveyed to the image reading unit.
It is characterized by providing.

The invention according to claim 11
In the image forming apparatus,
An image reading apparatus according to claim 10 ;
An image forming unit that forms an image of a document read by the image reading unit on paper;
It is characterized by providing.

  According to the present invention, even when Z-folding is formed on either side of a document, it is possible to improve the productivity and convenience by suppressing the occurrence of conveyance failure.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to an exemplary embodiment. FIG. 3 is a functional block diagram illustrating a control structure of the image forming apparatus according to the present embodiment. FIG. 10 is a diagram illustrating an example of conveying a document with Z-folding facing upward. It is a figure which shows an example of the detection result of the Z-fold detection sensor in the case of FIG. FIG. 10 is a diagram illustrating an example of conveying a document with a Z-fold downward. It is a figure which shows an example of the detection result of the Z-fold detection sensor in the case of FIG. It is a figure which shows an example of the operation | movement which expand | deploys the Z folding part of a document by a Z folding expansion part. It is a figure which shows an example which expand | deployed the Z folding part of the original. It is a figure which shows an example of the detection result of each pressing member in the case of FIG. 5 is a flowchart showing an operation of the image forming apparatus according to the present embodiment. It is a figure which shows schematic structure of the Z fold expansion | deployment part which concerns on the modification 1. FIG. It is a figure which shows schematic structure of the Z fold expansion | deployment part which concerns on the modification 2. FIG. It is a figure showing one modification provided with a contact type sensor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The image forming apparatus 1 according to the present embodiment is used as, for example, a printer or a digital copying machine, and as shown in FIGS. 1 and 2, an automatic document feeder 20, a scanner unit 30, an image forming unit 40, a paper feed unit, and the like. It comprises the part 50, the control part 10, etc.

The automatic document conveyance unit (document conveyance device) 20 is an ADF unit that executes sheet-through type image reading for reading an image while conveying the document.
The automatic document feeder 20 is a separation roller (not shown) for separating the document D placed on the document feed tray (document tray) T1 by the pickup roller 21 one by one. The document D to be read is sent to a predetermined conveyance path composed of a registration roller (not shown) having a predetermined posture and the respective conveyance rollers 22, 23, and conveyed to the reading position R of the scanner unit 30. Then, after the image of the document D is read by the scanner unit 30, the document D is discharged onto the document discharge tray T2 by the discharge roller 24.

  The document feed tray T1 of the automatic document feeder 20 is provided with a document size detection sensor 25 for detecting the document size of the placed document D. Document size information related to the document size detected by the document size detection sensor 25 is output to the control unit 10.

Further, a Z-fold detection sensor 26 for detecting the presence or absence of the Z-fold of the document D and the direction of the Z-fold is provided above the document feed tray T1 and upstream of the conveyance direction of the pickup roller 21. . The Z-fold detection sensor 26 is a reflective sensor, and detects the thickness (paper thickness) of the document D by irradiating the document D placed on the document feed tray T1 and receiving the reflected light. To do. That is, the Z-fold detection sensor 26 functions as a sheet thickness detection unit of the present invention. Paper thickness information related to the paper thickness detected by the Z-fold detection sensor 26 is output to the control unit 10.
The control unit 10 detects the presence or absence of the Z-fold of the document D and the direction of the Z-fold based on the change in the sheet thickness detected by the Z-fold detection sensor 26. That is, the control unit 10 functions as a Z-fold detection unit of the present invention. Regarding the Z-fold direction, when the document D is placed on the document feed tray T1, the case where the Z-fold is formed on the front side is “upward”, and the Z-fold is formed on the back side. The case shall be expressed as “downward”.

For example, as shown in FIG. 3, when an original D with Z-folding is directed upward, a change in the paper thickness is detected within a relatively short time as shown in FIG. 4, and the rate of change in the paper thickness is high. It is determined. Specifically, when it is determined that the change rate of the sheet thickness is equal to or greater than the first threshold, the control unit 10 determines that the change rate of the sheet thickness is high. Accordingly, when the control unit 10 determines that the change rate of the sheet thickness is high, the control unit 10 determines that the Z-fold is upward.
On the other hand, as shown in FIG. 5, when a document D having a Z-fold downward is conveyed, as shown in FIG. 6, a change in the paper thickness is detected within a relatively long time, and the rate of change in the paper thickness is low. It is determined. Specifically, the control unit 10 determines that the change rate of the sheet thickness is low when it is determined that the change rate of the sheet thickness is greater than or equal to a second threshold value that is lower than the first threshold value and less than the first threshold value. To do. Accordingly, when the control unit 10 determines that the change rate of the sheet thickness is low, the control unit 10 determines that the Z-fold is downward.
Note that if the change rate of the sheet thickness is determined to be less than the second threshold, the control unit 10 determines that a change in the sheet thickness has not been detected. If the control unit 10 determines that no change in the sheet thickness is detected, it determines that there is no Z-folding.

In addition, a Z-fold developing portion 27 that expands a Z-fold portion of the document D is provided on the downstream side in the transport direction of the pickup roller 21 and on the upstream side in the transport direction of the transport roller 22. The control unit 10 controls the driving of the Z-fold developing unit 27 based on the Z-fold direction of the document D. That is, the control unit 10 functions as a drive control unit of the present invention.
The Z-fold unfolding portion 27 has an upper pressing member 27a and a lower roller 27b for unfolding the Z-fold portion of the document D whose Z-fold is upward, and a lower side for unfolding the Z-fold portion of the document D whose Z-fold is downward. A pressing member 27c and an upper roller 27d.

The upper pressing member 27a is a square member provided on the upper side of the conveyance path and provided with a material (for example, rubber, low-adhesive glue, etc.) having a property of imparting conveyance resistance on the lower surface. It is configured to be movable. The lower roller 27b is disposed at a position opposed to the upper pressing member 27a across the document D to be conveyed, and is configured to be rotatable about an axis orthogonal to the conveyance direction and to be movable in the vertical direction. ing.
When the original D with the Z-fold upward is conveyed to the Z-fold developing portion 27, as shown in FIG. 7A, the upper pressing member 27a is moved downward by the lower roller at the timing when the Z-fold portion passes. 27b respectively moves upward to pinch the Z-folded portion of the document D. At this time, a material having resistance is arranged on the lower surface of the upper pressing member 27a (the contact surface with the document D), and the lower roller 27b rotates around an axis orthogonal to the conveyance direction. The lower surface side is conveyed while the conveyance on the upper surface (surface on which Z-folding is formed) side is suppressed. As a result, the original D is stretched in the transport direction, and the Z-folded portion of the original D in which the Z-fold is upward can be developed.

The lower pressing member 27c is a square member provided on the lower side of the conveyance path and having a resistance material on the upper surface, and is configured to be movable in the vertical direction. The upper roller 27d is disposed at a position facing the lower pressing member 27c with the document D to be conveyed interposed therebetween, and is configured to be rotatable about an axis orthogonal to the conveyance direction and to be movable in the vertical direction. ing.
When the document D with the Z-folding downward is conveyed to the Z-fold developing portion 27, as shown in FIG. 7B, the lower pressing member 27c is moved upward by the upper roller at the timing when the Z-folding portion passes. 27d moves downward to sandwich the Z-folded portion of the document D. At this time, a material having resistance is disposed on the upper surface (contact surface with the document D) of the lower pressing member 27c, and the upper roller 27d rotates about an axis orthogonal to the transport direction. The lower surface (the surface on which the Z fold is formed) side is suppressed, and the upper surface side is conveyed. Thereby, the document D is stretched in the transport direction, and the Z-folded portion of the document D in which the Z-fold is downward can be developed.
The Z-fold developing unit 27 does not particularly operate when the document D without Z-folding is conveyed, and allows the document D to pass through.

Further, the Z folding and unfolding portion 27 detects a pressure on the document D when the document D is developed (clamped) by the upper pressing member 27a and the lower roller 27b or the lower pressing member 27c and the upper roller 27d. 28 (see FIG. 2) is provided. Pressure information related to the pressure detected by the pressure detection unit 28 is output to the control unit 10.
For example, as shown in FIG. 8, when a document D on which Z-folding has been formed is stretched in the transport direction and the Z-folded portion is developed, as shown in FIG. An arrow E1) in the figure is detected. Therefore, when the control unit 10 detects an instantaneous drop in pressure on the document D, the control unit 10 determines that the Z-folded portion has been developed.
Then, when it is determined that the Z-folded portion has been deployed, the control unit 10 moves the pressing members 27a and 27c and the rollers 27b and 27d that constitute the Z-fold developing unit 27 to the original positions.

  The scanner unit 30 is configured to include an optical system such as a light source and a reflecting mirror, and irradiates the light source to the document D transported to the reading position R through a predetermined transport path or the document D placed on the platen glass. And receives the reflected light. Further, the scanner unit 30 converts the received reflected light into an electric signal and outputs it to the control unit 10. That is, the scanner unit 30 functions as an image reading unit of the present invention.

The image forming unit 40 includes a yellow image forming unit Y, a magenta image forming unit M, a cyan image forming unit C, a black image forming unit K, an intermediate transfer belt B, a fixing device F, and the like.
Each image forming unit YMCK forms yellow, magenta, cyan, and black toner images on the photoconductive drum 41, and primarily transfers the YMCK color toner images formed on the photoconductive drum 41 to the intermediate transfer belt B.
Since the configuration and operation of each image forming unit YMCK are the same, a series of image forming operations performed by the image forming unit 40 will be described below taking the yellow image forming unit Y as an example.

  The yellow image forming unit Y includes a photosensitive drum 41, a charging device 42, an exposure device 43, a developing device 44, a primary transfer roller 45, a secondary transfer roller 46, a cleaning device 47, and the like.

The photoreceptor drum 41 is composed of a photoreceptor layer having a surface composed of an organic semiconductor layer in which a phthalocyanine pigment is dispersed in polycarbonate and a charge transport layer.
The charging device 42 uniformly charges the photosensitive drum 41.
The exposure device 43 exposes the non-image area of the photosensitive drum 41 based on the image data Dy from the control unit 10 to remove the exposed portion of the charge, and forms an electrostatic latent image on the image area of the photosensitive drum 41. Form.
The developing device 44 supplies toner that is a developer onto the electrostatic latent image formed on the photosensitive drum 41, and forms a yellow toner image on the photosensitive drum 41.

The primary transfer roller 45 primarily transfers the yellow toner image formed on the photosensitive drum 41 to the intermediate transfer belt B.
Similarly, the other image forming units MCK also primarily transfer magenta, cyan, and black toner images onto the intermediate transfer belt B. As a result, a color toner image of each color of YMCK is formed on the intermediate transfer belt B.
The secondary transfer roller 46 secondarily transfers the YMCK color toner images formed by being transferred to the intermediate transfer belt B onto the paper P conveyed from the paper supply unit 50.

The image forming unit 40 heats and pressurizes the sheet P on which the toner images of each color of YMCK are secondarily transferred by the fixing device F, and then discharges the sheet P to the outside through a predetermined conveyance path.
The above is a series of image forming operations by the image forming unit 40.

The cleaning device 47 removes residues such as residual toner and paper dust remaining on the surface of the photosensitive drum 41 after the primary transfer. Further, the cleaning device 48 removes residues remaining on the intermediate transfer belt B after the secondary transfer.
The cleaning device 47 and the cleaning device 48 are the same in that they remove residues remaining on the photosensitive drum 41 or the intermediate transfer belt B, and perform the same configuration and operation.

  The paper feed unit 50 includes a plurality of trays, and each tray stores a plurality of different types of paper P. The paper feeding unit 50 feeds the paper P accommodated by a predetermined conveyance path to the image forming unit 40.

  The control unit 10 is configured to include a CPU, a RAM, a ROM, and the like. The CPU expands various programs stored in the ROM to the RAM, and cooperates with the expanded various programs, so that the automatic document conveyance unit 20, The operation of each unit of the image forming apparatus 1 such as the scanner unit 30, the image forming unit 40, and the paper feeding unit 50 is comprehensively controlled (see FIG. 2). For example, the control unit 10 receives the electrical signal from the scanner unit 30 and performs various image processing, and outputs the image data Dy, Dm, Dc, and Dk of each color of YMCK generated by the image processing to the image forming unit 40. . The control unit 10 controls the operation of the image forming unit 40 to form an image on the paper P.

  Next, the operation of the image forming apparatus 1 according to the present embodiment will be described with reference to the flowchart of FIG. This operation is started when a bundle of documents D is set on the document feed tray T1 of the automatic document feeder 20.

First, the control unit 10 acquires document size information related to the document size of the document D placed on the document feed tray T1 detected by the document size detection sensor 25 (step S1).
Next, the control unit 10 starts conveying the document D for which the document size information has been acquired in step S1 (step S2).

Next, the control unit 10 continuously acquires sheet thickness information related to the sheet thickness of the document D detected by the Z-fold detection sensor 26, and monitors the sheet thickness information (step S3).
Next, the control unit 10 determines whether or not a change in sheet thickness is detected (step S4). Specifically, when it is determined that the change rate of the sheet thickness is equal to or greater than the second threshold, the control unit 10 determines that a change in the sheet thickness has been detected. On the other hand, when it is determined that the change rate of the sheet thickness is less than the second threshold, the control unit 10 determines that the change in the sheet thickness is not detected. The control unit 10 determines that no change in the paper thickness is detected when no change in the paper thickness is detected before the document D completely passes through the Z-fold detection sensor 26.
When it is determined that the change in the sheet thickness is detected (step S4: YES), the control unit 10 proceeds to the next step S5.
On the other hand, if the control unit 10 determines that no change in the sheet thickness is detected (step S4: NO), the control unit 10 proceeds to step S14.

Next, the control unit 10 determines whether or not it is determined that the change rate of the sheet thickness is low (step S5). Specifically, when it is determined that the change rate of the sheet thickness is less than the first threshold, the control unit 10 determines that the change rate of the sheet thickness is low. On the other hand, when it is determined that the change rate of the sheet thickness is equal to or greater than the first threshold, the control unit 10 determines that the change rate of the sheet thickness is high.
When the control unit 10 determines that the rate of change in the sheet thickness is low (step S5: YES), the control unit 10 determines that the Z-folding is downward (step S6), and controls the Z-fold developing unit 27 to control “Z-folding downwards”. Is set to “control for original D,” (step S7).
On the other hand, when the control unit 10 does not determine that the change rate of the sheet thickness is low, that is, determines that the change rate of the sheet thickness is high (step S5: NO), the control unit 10 determines that the Z-fold is upward ( In step S8), the control of the Z-fold unfolding portion 27 is set to "control for the document D whose Z-fold is upward" (step S9).

  After the process of step S7 or step S9, the control unit 10 calculates the distance from the leading end of the document D in the transport direction to the Z-folded portion based on the transport time of the document D and the change in the sheet thickness (step S7). S10). That is, the control unit 10 functions as a distance calculation unit of the present invention. Specifically, when conveying the original D with the Z-fold upward, as shown in FIG. 4, the control unit 10 determines the distance to the Z-fold portion based on the time h1 until the sheet thickness starts to change. calculate. On the other hand, when conveying the original D with the Z-folding downward, the control unit 10 determines the distance to the Z-folding portion based on the time h2 until the paper thickness is changed and becomes constant as shown in FIG. calculate.

  Next, the control unit 10 controls the driving of the Z-fold developing unit 27 based on the distance to the Z-folded part calculated in step S10 to press the Z-folded part of the document D (step S11). Specifically, when the document D whose Z-folding is upward is conveyed to the Z-fold developing unit 27, the control unit 10 moves the upper pressing member 27a downward and the lower roller 27b upward. Then, the document D is sandwiched (see FIG. 7A). On the other hand, when the document D whose Z-folding is downward is conveyed to the Z-fold developing unit 27, the control unit 10 moves the lower pressing member 27c upward and the upper roller 27d downward, respectively. (See FIG. 7B).

Next, the control unit 10 continuously acquires pressure information related to “pressure on the document D when the Z-folded portion is unfolded” detected by the pressure detection unit 28, and detects a change in pressure on the document D. It is determined whether or not (step S12). Specifically, the control unit 10 determines that a change in pressure on the document D has been detected when an instantaneous decrease in pressure on the document D is detected.
When it is determined that a change in pressure on the document D has been detected (step S12: YES), the control unit 10 determines that the Z-folded portion of the document D has been developed, and proceeds to the next step S13.
On the other hand, when it is determined that a change in pressure on the document D is not detected (step S12: NO), the control unit 10 repeats the process of step S12 until a change is detected.

  Next, the control unit 10 releases the pressing of the Z-folded portion of the document D by the Z-fold developing unit 27 (step S13). Specifically, the control unit 10 moves the pressing members 27a and 27c and the rollers 27b and 27d constituting the Z folding and unfolding unit 27 to the original positions.

  Next, the control unit 10 causes the scanner unit 30 to read the image of the original D without Z-folding or the original D with the Z-folded portion developed (step S14).

Next, the control unit 10 determines whether or not the next document D exists, that is, whether or not the document D is placed on the document feed tray T1 (step S15).
When it is determined that the next document D exists (step S15: YES), the control unit 10 proceeds to step S2 and starts conveying the next document D.
On the other hand, when it is determined that the next document D does not exist (step S15: NO), the control unit 10 ends the process.

As described above, in the image forming apparatus 1 according to the present embodiment, the Z-fold detection is detected by the Z-fold detection unit (control unit 10) that detects the presence / absence and Z-folding direction of the document, and the Z-fold detection unit. A Z-fold developing unit 27 that unfolds the Z-folded portion of the original document and a drive control unit (control unit 10) that controls the driving of the Z-fold developing unit based on the Z-folding direction detected by the Z-fold detecting unit. And comprising.
Therefore, according to the image forming apparatus 1 according to the present embodiment, the occurrence of conveyance failure can be suppressed regardless of whether the Z-fold is formed on either side of the document. Productivity and convenience such as reading can be improved.

Further, the image forming apparatus 1 according to the present embodiment includes a sheet thickness detection unit (Z-fold detection sensor 26) that detects the sheet thickness of the document. The Z-fold detection unit determines that the Z-fold is upward when it determines that the change rate of the paper thickness detected by the paper thickness detection unit is equal to or greater than the first threshold, and changes the paper thickness. When it is determined that the rate is greater than or equal to a second threshold value that is lower than the first threshold value and less than the first threshold value, it is determined that the Z-fold is downward.
Therefore, according to the image forming apparatus 1 according to the present embodiment, the presence / absence of Z-folding and the direction of Z-folding can be accurately detected with a simple configuration. it can.

The image forming apparatus 1 according to the present embodiment further includes a distance calculation unit (control unit 10) that calculates the distance to the Z-folded portion of the document based on the document conveyance time and the change in sheet thickness. . Further, the drive control unit controls the driving of the Z-fold developing unit 27 based on the distance to the Z-folded portion calculated by the distance calculating unit.
Therefore, according to the image forming apparatus 1 according to the present embodiment, the unfolding operation of the Z-folded portion can be efficiently executed, and thus the productivity related to document conveyance can be further improved.

Further, according to the image forming apparatus 1 according to the present embodiment, the Z-fold developing unit 27 is provided with the pressure detecting unit 28 that detects the pressure on the document when the Z-folded portion is developed. Further, the drive control unit controls the driving of the Z-fold developing unit 27 based on the change in pressure detected by the pressure detection unit 28.
Therefore, according to the image forming apparatus 1 according to the present embodiment, it is possible to accurately detect the timing at which the expansion of the Z-folded portion is completed, so that a conveyance failure due to a delay in the timing of releasing the pressure on the document occurs. Can be suppressed, and a decrease in productivity due to poor conveyance can be suppressed.

Further, according to the image forming apparatus 1 according to the present embodiment, the Z folding and unfolding portion 27 is provided on the upper side of the conveyance path, and the lower surface is provided with a material having a property of imparting conveyance resistance, and can move in the vertical direction. An upper presser member 27a, a lower roller 27b which is disposed at a position facing the upper presser member 27a across the document to be transported, rotates about an axis orthogonal to the transport direction and is movable in the vertical direction, and transport A material provided on the lower side of the path and having a property of imparting conveyance resistance is disposed on the upper surface, and is opposed to the lower pressing member 27c movable in the vertical direction and the lower pressing member 27c sandwiching the conveyed document. And an upper roller 27d that rotates around an axis perpendicular to the transport direction and is movable in the vertical direction. In addition, when the Z-fold portion is upward when the drive control unit expands the Z-fold portion, the drive control unit holds the Z-fold portion by the upper pressing member 27a and the lower roller 27b, and when the Z-fold portion is downward. Then, the Z-folded portion is clamped by the lower pressing member 27c and the upper roller 27d.
Therefore, according to the image forming apparatus 1 according to the present embodiment, the dedicated members corresponding to the respective Z-fold directions are provided, so that the control related to the unfolding operation of the Z-fold portion can be easily performed. .

  As mentioned above, although concretely demonstrated based on embodiment which concerns on this invention, this invention is not limited to the said embodiment, It can change in the range which does not deviate from the summary.

(Modification 1)
For example, in the example illustrated in FIG. 11, the configuration of the Z-fold developing portion 27 </ b> A is different from that of the embodiment.
Specifically, as shown in FIG. 11, the Z-fold developing portion 27A according to Modification 1 includes an upper roller 27e provided on the upper side of the conveyance path, a lower roller 27f provided on the lower side of the conveyance path, It is configured with. The upper roller 27e and the lower roller 27f are arranged at positions facing each other with the document D being conveyed therebetween.

The upper roller 27e is configured to be able to switch between a rotation mode that rotates around an axis orthogonal to the conveyance direction and a fixed mode that is fixed so as not to rotate, under the control of a drive motor (not shown). The upper roller 27e is configured to be movable in the vertical direction.
Similarly to the upper roller 27e, the lower roller 27f is configured to be able to switch between a rotation mode and a fixed mode under the control of a drive motor (not shown), and is configured to be movable in the vertical direction.
That is, the upper roller 27e and the lower roller 27f function as the rollers of the present invention.
As shown in FIG. 11A, the upper roller 27e and the lower roller 27f are arranged with the upper roller 27e moved upward and the lower roller 27f moved downward, respectively, as shown in FIG. It is in a state. Thereby, the document D is easily conveyed between the upper roller 27e and the lower roller 27f.

  When the document D with the Z-fold upward is conveyed to the Z-fold developing portion 27A, as shown in FIG. 11B, the upper roller 27e is moved downward and the lower roller 27f at the timing when the Z-fold portion passes. Respectively move upward and pinch the Z-folded portion of the document D. Further, the upper roller 27e provided on the upper surface (surface on which Z-folding is formed) of the document D is driven in the “fixed mode”, and the other lower roller 27f is driven in the “rotation mode”. Accordingly, the lower surface side of the document D is conveyed while the conveyance of the upper surface side of the document D is suppressed. As a result, the original D is stretched in the transport direction, and the Z-folded portion of the original D in which the Z-fold is upward can be developed.

  On the other hand, when the original D having the Z-fold downward is conveyed to the Z-fold developing portion 27A, as shown in FIG. 11C, the upper roller 27e is moved downward at the timing when the Z-fold portion passes. Each of the rollers 27f moves downward to sandwich the Z-folded portion of the document D. Further, the lower roller 27f provided on the lower surface (surface on which Z-folding is formed) of the document D is driven in the “fixed mode”, and the other upper roller 27e is driven in the “rotation mode”. Accordingly, the upper surface side of the document D is conveyed while the conveyance of the lower surface side of the document D is suppressed. Thereby, the document D is stretched in the transport direction, and the Z-folded portion of the document D in which the Z-fold is downward can be developed.

As described above, according to the image forming apparatus 1 according to the first modification, the Z folding and unfolding portion 27A is disposed at a position facing the document to be transported, rotates around an axis orthogonal to the transport direction, and A pair of rollers (upper roller 27e, lower roller 27f) that can move in the vertical direction is provided. In addition, when the Z-folded portion is developed, the drive control unit causes the pair of rollers to sandwich the Z-folded portion, and stops rotation of the roller on the surface side where the Z-fold is formed among the pair of rollers.
Therefore, according to the image forming apparatus 1 according to the first modification, the number of members constituting the Z-fold developing portion 27A can be reduced, so that it can be easily manufactured and the manufacturing cost can be reduced.

(Modification 2)
Moreover, in the example shown in FIG. 12, the structure of Z folding | deployment part 27B differs compared with embodiment.
Specifically, as shown in FIG. 11, the Z-fold developing portion 27B according to the second modification includes an upper claw member 27g provided on the upper side of the conveyance path and a lower claw member 27h provided on the lower side of the conveyance path. And comprising. The upper claw member 27g and the lower claw member 27h are arranged at positions facing each other with the document D being conveyed therebetween.

The upper claw member 27g is configured to be rotatable up and down around a shaft 271 that fixes a downstream end portion in the transport direction under the control of a drive motor (not shown).
Similarly to the upper claw member 27g, the lower claw member 27h is configured to be rotatable up and down around a shaft 272 that fixes the downstream end portion in the transport direction under the control of a drive motor (not shown).
In the initial state, the upper claw member 27g and the lower claw member 27h are arranged with the upper claw member 27g rotated upward and the lower claw member 27h rotated downward, respectively, as shown in FIG. Thus, the upstream ends in the transport direction are separated from each other. Thereby, the document D is easily conveyed between the upper claw member 27g and the lower claw member 27h.

  When the document D with the Z-fold upward is transported to the Z-fold unfolding portion 27B, as shown in FIG. 12B, the upper claw member 27g is lowered downward at the timing before the Z-fold portion passes. The side claw members 27h rotate upward to sandwich the downstream side in the transport direction with respect to the Z-folded portion of the document D. When the conveyance is continued in this state, the Z-folded portion comes into contact with the upper claw member 27g, and the conveyance of the upper surface side of the document D is suppressed. As a result, the original D is stretched in the transport direction, and the Z-folded portion of the original D in which the Z-fold is upward can be developed.

  When the document D with the Z-folding downward is conveyed to the Z-fold developing portion 27B, as shown in FIG. 12C, the upper claw member 27g is moved downward (however, at the timing before the Z-folded portion passes) The lower claw member 27h rotates in the upward direction (in the position above the case of FIG. 12B) in the upper position than in the case of FIG. And sandwich the downstream side in the transport direction. When conveyance is continued in this state, the Z-folded portion comes into contact with the lower claw member 27h, and conveyance on the lower surface side of the document D is suppressed. Thereby, the document D is stretched in the transport direction, and the Z-folded portion of the document D in which the Z-fold is downward can be developed.

As described above, according to the image forming apparatus 1 according to the modified example 2, the Z folding and unfolding portion 27B is disposed at a position facing the document to be transported and fixes the downstream end in the transport direction. 272, and a pair of claw portions (upper claw member 27g, lower claw member 27h) that can be rotated up and down around the center. Further, the drive control unit causes the pair of claw members to sandwich the downstream side in the transport direction with respect to the Z-folded portion when the Z-folded portion is deployed.
Therefore, according to the image forming apparatus 1 according to the modified example 2, since the number of members constituting the Z-fold developing portion 27B can be reduced, it can be easily manufactured and the manufacturing cost can be reduced.

(Other variations)
Further, the paper type of the document D may be detected based on the paper thickness detected by the paper thickness detection unit, and the drive of the Z-fold developing unit 27 may be controlled based on the detected paper type. . In this case, the control unit 10 functions as a paper type detection unit of the present invention. Here, the paper type is a type of paper that can be identified based on the paper thickness, and examples thereof include thin paper, plain paper, and thick paper.
As a result, an appropriate pressure can be applied according to the type of paper, so that the Z-folded portion can be unfolded reliably, and the decrease in productivity due to poor conveyance can be more reliably suppressed. it can.

Further, based on the Z-folding direction detected by the Z-fold detection unit, at least one of the driving torque of the transport roller 22 disposed on the downstream side in the transport direction with respect to the Z-fold developing unit 27 and the transport speed of the document D. May be controlled. In this case, the control unit 10 functions as a conveyance control unit of the present invention. In particular, when a document D having a Z-folded downward is conveyed to the Z-fold developing portion 27, the conveyance resistance at the time of developing the Z-folded portion tends to become stronger, so that the driving torque of the conveying roller 22 is further increased. Or a control for increasing the conveyance speed of the document D is performed.
As a result, the conveyance operation can be controlled in consideration of the resistance of the document conveyance, so that it is possible to suppress the occurrence of problems related to the unfolding operation and the conveyance operation of the Z-fold portion.

  In the above embodiment, the paper thickness of the document D is detected by the Z-fold detection sensor 26, and the presence / absence of the Z-fold and the direction of the Z-fold are detected based on the change in the paper thickness. Is not to be done. For example, an imaging unit such as a camera is provided instead of the Z-fold detection sensor 26, and the presence / absence of Z-folding and the direction of Z-folding are detected based on the image of the document D captured by the imaging unit. Also good.

Further, as shown in FIG. 13, instead of the Z-fold detection sensor 26, contact sensors (contact detection units) 26a and 26b are provided one above the other with the document D in between, and a pair of contact sensors 26a. 26b, the presence or absence of Z-folding and the direction of Z-folding may be detected based on the contact pattern with the document D detected by 26b.
For example, as shown in FIG. 13A, when transporting an original D with Z-folding upward, the Z-folded portion of the original D comes into contact with the upper contact type sensor 26a disposed on the upper side, and the lower side thereof. The disposed lower contact type sensor 26b contacts from the leading edge to the trailing edge of the document D.
On the other hand, as shown in FIG. 13B, when conveying the original D with the Z-fold downward, the upper contact type sensor 26a disposed on the upper side has a Z-folded portion from the front portion of the Z-folded portion of the original D. The lower end contact sensor 26b disposed on the lower side is in contact with the vicinity of the front end of the document D and the Z-folded portion.
Further, when the original D without Z-folding is conveyed, the original D is not in contact with the upper contact sensor 26a disposed on the upper side, and the original D on the lower contact sensor 26b disposed on the lower side. Touch from the tip to the end.
The control unit 10 detects the presence or absence of Z-folding and the direction of Z-folding based on the contact pattern.

  In the above embodiment, the distance to the Z-folded portion of the document D is calculated based on the conveyance time of the document D and the change in the paper thickness, and the driving of the Z-fold developing unit 27 is controlled based on the distance. However, the present invention is not limited to this. That is, the driving of the Z-fold developing unit 27 may be controlled at a uniform timing according to the Z-fold direction of the document D.

  In the above-described embodiment, the Z-fold developing unit 27 is provided with the pressure detection unit 28 that detects the pressure applied to the document when the Z-folded portion is developed, and based on the change in pressure detected by the pressure detection unit 28. Thus, the pressing of the Z-folded portion by the Z-fold developing portion 27 is released, but the present invention is not limited to this. That is, the pressure detection unit 28 may be omitted, and the pressing of the Z-folded portion may be released based on the pressing time or the like instead of the pressure change.

  In addition, the detailed configuration of each apparatus constituting the image forming apparatus and the detailed operation of each apparatus can be changed as appropriate without departing from the spirit of the present invention.

1 Image forming apparatus 10 Control unit (Z fold detection unit, drive control unit, distance calculation unit, paper type detection unit, conveyance control unit)
20 Automatic document feeder (document feeder)
21 Pickup rollers 22, 23 Conveyance roller 24 Discharge roller 25 Document size detection sensor 26 Z-fold detection sensor (paper thickness detection unit)
26a, 26b Contact type sensor (contact detection unit)
27, 27A, 27B Z folding and unfolding portion 27a Upper pressing member 27b Lower roller 27c Lower pressing member 27d Upper roller 27e, 27f Roller 27g, 27h Claw members 271, 272 Shaft 28 Pressure detection unit T1 Document feeding tray (document tray) )
T2 Document discharge tray 30 Scanner unit (image reading unit)
40 Image forming unit 41 Photosensitive drum 42 Charging device 43 Exposure device 44 Developing device 45 Primary transfer roller 46 Secondary transfer rollers 47 and 48 Cleaning device B Intermediate transfer belt F Fixing device 50 Paper feeding unit D Document

Claims (11)

In a document transport device that transports a document placed on a document tray,
A Z-fold detection unit that detects whether the document is Z-folded and whether the Z-fold direction is upward or downward ;
A Z-fold unfolding section for unfolding a Z-fold portion of the document in which the Z-fold is detected by the Z-fold detection section;
A drive control unit that controls the driving of the Z-fold unfolding unit based on the Z-fold direction detected by the Z-fold detection unit;
Equipped with a,
The Z-fold unfolding part is
An upper presser member that is provided on the upper side of the transport path and is provided with a material having a property of imparting transport resistance to the lower surface, and is movable in the vertical direction;
A lower roller that is disposed at a position facing the upper pressing member across the document to be conveyed, rotates about an axis orthogonal to the conveying direction, and is movable in the vertical direction;
A lower presser member that is provided on the lower side of the transport path, is provided with a material having a property of imparting transport resistance to the upper surface, and is movable in the vertical direction;
An upper roller that is disposed at a position facing the lower pressing member across the document to be conveyed, rotates about an axis perpendicular to the conveying direction, and is movable in the vertical direction;
With
When the Z-fold is upward when the drive control unit expands the Z-fold portion, the Z-fold portion is sandwiched between the upper pressing member and the lower roller and the Z-fold is downward. Is a document conveying apparatus characterized in that the Z-folded portion is clamped by the lower pressing member and the upper roller . In a document transport device that transports a document placed on a document tray,
A Z-fold detection unit that detects whether the document is Z-folded and whether the Z-fold direction is upward or downward;
A Z-fold unfolding section for unfolding a Z-fold portion of the document in which the Z-fold is detected by the Z-fold detection section;
A drive control unit that controls the driving of the Z-fold unfolding unit based on the Z-fold direction detected by the Z-fold detection unit;
With
The Z folding and unfolding portion is disposed at a position facing the document to be conveyed, and includes a pair of rollers that rotate about an axis perpendicular to the conveyance direction and move in the vertical direction.
  When the Z-folded portion is unfolded, the drive control unit sandwiches the Z-folded portion by the pair of rollers, and rotates the roller on the surface side of the pair of rollers on which the Z-fold is formed. A document conveying device characterized by being stopped. In a document transport device that transports a document placed on a document tray,
A Z-fold detection unit that detects whether the document is Z-folded and whether the Z-fold direction is upward or downward;
A Z-fold unfolding section for unfolding a Z-fold portion of the document in which the Z-fold is detected by the Z-fold detection section;
A drive control unit that controls the driving of the Z-fold unfolding unit based on the Z-fold direction detected by the Z-fold detection unit;
With
The Z folding and unfolding portion is provided at a position facing the document to be conveyed, and includes a pair of claw members that can rotate up and down around an axis that fixes the downstream end in the conveyance direction,
The drive control unit rotates the upper claw member downward and the lower claw member upward when unfolding the Z-folded portion,
When the Z-folded portion is downward, the pair of claw members are rotated to a position above the case where the Z-fold is upward,
An original conveying apparatus, wherein the pair of claw members sandwich the downstream side in the conveying direction from the Z-folded portion. A paper thickness detector for detecting the paper thickness of the original;
The Z-fold detection unit determines that the Z-fold is upward and determines a change in the paper thickness when it is determined that the change rate of the paper thickness detected by the paper thickness detection unit is equal to or greater than the first threshold. If the rate is determined to be less than the first and the second threshold value or more lower than the threshold of the first threshold value, one of claims 1, wherein the determining the Z folding is downward 3 document feeder according to one paragraph or. A distance calculating unit that calculates a distance to the Z-folded portion of the document based on the transport time of the document and the change in the paper thickness;
5. The document conveying apparatus according to claim 4 , wherein the drive control unit controls driving of the Z-fold developing unit based on a distance to the Z-folded portion calculated by the distance calculating unit. A paper type detection unit that detects the paper type of the document based on the paper thickness detected by the paper thickness detection unit;
The drive control unit based on the sheet type is detected by the paper type detection unit, document feeder according to claim 4 or 5, characterized in that for controlling the drive of the Z-fold expansion unit. A contact detection unit for detecting a contact pattern with the document;
The Z-fold detection unit detects presence / absence of Z-folding and Z-folding direction of the document based on a contact pattern with the document detected by the contact detection unit . The document conveying device according to any one of the above. The Z-fold developing portion is provided with a pressure detection unit that detects a pressure applied to the document by the Z-fold developing portion when the Z-fold portion is expanded.
3. The document conveying apparatus according to claim 1, wherein the drive control unit controls driving of the Z folding and unfolding unit based on a change in pressure detected by the pressure detection unit. Based on the direction of the Z-fold detected by the Z-fold detection unit , the original reaches the transport roller disposed downstream in the transport direction from the Z-fold unfolding unit before the Z-fold portion has been unfolded. , document feeder according to any one of claims 1-8, characterized in that it comprises a conveyance control unit for controlling an at least one of the transport speed of the drive torque and the document of the conveying roller. An image reading unit for reading an image of a document;
The document conveying device according to any one of claims 1 to 9 , wherein the document placed on a document tray is conveyed to the image reading unit.
An image reading apparatus comprising: An image reading apparatus according to claim 10 ;
An image forming unit that forms an image of a document read by the image reading unit on paper;
An image forming apparatus comprising:

Images