JP5504140B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus including an automatic document feeder (ADF).

Some image forming apparatuses include an ADF (Auto Document Feeder). The ADF sequentially conveys the originals placed on the original placement unit one by one to the reading surface for reading the image of the original, and discharges the originals whose images are read on the reading surface to the original stacking unit.
In such an image forming apparatus, it is determined whether or not the document conveyed by the ADF exceeds the sheet passing area. If it is determined that the document is conveyed beyond the sheet passing area, the document is Is prohibited to prevent paper jamming and document damage (see Patent Document 1).

Japanese Patent Laid-Open No. 10-63043

By the way, in addition to the case where only one type of document (eg, A4 size) is placed on the ADF document placement unit, for example, an A3 size (large size) document and an A5 size (small size) Size) document may be mixed. Even in these cases, the ADF conveys the originals one by one to the reading surface.
However, since the invention described in Patent Document 1 determines whether or not a document is conveyed out of the sheet passing area, even when a small-sized document is conveyed at an incline, the small size is determined. In some cases, it is not determined that the original document is conveyed beyond the sheet passing area. In this case, the invention described in Patent Document 1 cannot prohibit the conveyance of the document, and the document may be clogged or the document may be damaged.

  An object of the present invention is to provide an image forming apparatus that reduces the possibility of document jamming and the possibility of damaging the document.

  The present invention provides a document reading unit having a first reading sensor that reads an image on the front side of a document as a first image, and a second reading sensor that reads an image on the back side of the document as a second image, and the document reading unit. And a document conveying section that conveys the document to the document, and detects the inclination of the document based on the first image read by the first reading sensor, and based on the second image read by the second reading sensor. An inclination detection unit that detects the inclination of the document, an inclination of the document detected by the inclination detection unit based on the first image, and an inclination of the document detected by the inclination detection unit based on the second image Are each equal to or greater than a predetermined value, and the document inclination detected by the inclination detection unit based on the first image and the document inclination detected by the inclination detection unit based on the second image. A first determination unit that performs determination of at least one of the difference between the first image and the difference between the first image and the original, and an original detected based on the second image and an inclination of the original detected based on the first image Or the document detected based on the second image and the document detected based on the first image, or the document detected based on the second image. If the first determination unit determines that the difference from the inclination is equal to or greater than a predetermined value, the document conveyance unit is controlled to stop the conveyance of the next document according to a predetermined condition, or The present invention relates to an image forming apparatus comprising: a conveyance control unit that controls the document conveyance unit so as to convey the next document at a slower speed than the conveyance speed of the document whose image is read by the document reading unit.

  The image forming apparatus also includes a first original as a first original and a second original as a second original conveyed after the first original is conveyed by the original conveying unit. The inclination of the original detected by the inclination detector based on the image, the first difference and the original difference detected by the inclination detector based on the second image of the first original, and the inclination detector The difference between the inclination of the original detected based on the first image of the second original and the difference between the original inclination detected based on the second image of the second original and the second difference by the inclination detection unit. Is determined to be equal to or greater than a predetermined value, and the conveyance control unit is configured such that the difference between the first difference and the second difference is equal to or greater than a predetermined value by the second determination unit. If it is determined that the next original following the second original is carried according to a predetermined condition The controls the document feeder so as to stop, or, it is preferable to slower than the transport speed of the second document controls the document feeder so as to convey the next original.

  The image forming apparatus also includes a display unit and a conveyance of the document whose image is read by the document reading unit when the document conveyance unit is controlled by the conveyance control unit to stop conveyance of the next document. It is preferable to include a display control unit that displays a warning on the display unit when the document transport unit is controlled by the transport control unit to transport the next document at a speed lower than the speed.

  The present invention can provide an image forming apparatus that reduces the possibility of document jamming and the possibility of damaging the document.

1 is a diagram illustrating an overall configuration of a copier according to an embodiment of an image forming apparatus. 2 is a block diagram illustrating a functional configuration of a copier. FIG. 6 is a flowchart for explaining the operation of the copier.

  A copier according to an embodiment of an image forming apparatus of the present invention will be described below with reference to the drawings. First, the overall configuration of the copy machine 1 will be described. FIG. 1 is a diagram for explaining an overall configuration of a copier 1 according to an embodiment of an image forming apparatus.

The copier 1 includes a document transport unit 10, a document reading unit 20, a paper transport unit 30, an image forming unit 40, a transfer unit 50, and a fixing unit 60.
The document transport unit 10 is an ADF, and transports the document G to a document reading unit 20 described later. The document transport unit 10 includes a document placement unit 11, a first feed roller 12 as a driving roller, a guide 13, a timing roller pair 14, and a document discharge unit 15. Documents of different sizes can be mixed and placed on the document placement unit 11. The first feed roller 12 supplies the document G placed on the document placement unit 11 to the timing roller pair 14 one by one in order. The timing roller pair 14 is a timing at which the original reading unit 20 reads an image of the original G and a timing at which the original G is supplied to a position where the image of the original G is read by the original reading unit 20 (position where the guide 13 is disposed). In order to match, the conveyance of the original G or the conveyance stop of the original G is performed. The guide 13 guides the conveyed document G to a first reading surface 21a described later. The document discharge unit 15 discharges the document G whose image has been read by the document reading unit 20 (passed through the guide 13) to the outside of the copier body 2.
A document stacking unit 16 is formed outside the copying machine main body 2 in the document discharge unit 15. In the document stacking unit 16, the documents G discharged from the document discharge unit 15 are stacked and stacked.

  The document reading unit 20 includes a first reading surface 21a and a second reading surface 22a. The first reading surface 21 a is formed along the upper surface of the first contact glass 21 disposed to face the guide 13 and serves as a surface for reading an image of the document G. The second reading surface 22a is disposed adjacent to the first reading surface 21a (in the case shown in FIG. 1, over the most right side of the first reading surface 21a). The second reading surface 22 a is used when reading an image of the document G without using the document transport unit 10. The second reading surface 22a is formed along the upper surface of the second contact glass 22 on which the document G is placed, and serves as a surface for reading an image of the document G.

  The document reading unit 20 includes an illumination unit 23, a first mirror 24, a second mirror 25, a third mirror 26, an imaging lens 27, and an imaging unit 28 inside the copier body 2. . The illumination unit 23 and the first mirror 24 move in the sub-scanning direction X, respectively. The second mirror 25 and the third mirror 26 are disposed on the left side of the illumination unit 23 and the first mirror 24 in FIG. Further, the second mirror 25 and the third mirror 26 are the first reading surface 21 a or the second reading surface 22 a through the first mirror 24, the second mirror 25, the third mirror 26, and the imaging lens 27. To the imaging unit 28 while moving in the sub-scanning direction X while keeping the distance (optical path length) constant.

  The illumination unit 23 is a light source that irradiates the original G with light. The first mirror 24, the second mirror 25, and the third mirror 26 are mirrors for guiding the light reflected by the document G to the imaging lens 27 while keeping the optical path length constant. The imaging lens 27 focuses the light incident from the third mirror 26 on the imaging unit 28. The imaging unit 28 is an imaging device for obtaining image data based on an imaged optical image by converting incident light into an electrical signal. For example, the imaging unit 28 is a CCD (Charge Coupled Device) or a CMOS (Complementary). It is an image sensor such as Metal Oxide Semiconductor). The imaging unit 28 serves as a first reading sensor that reads an image on the surface of the document G as a first image. Here, one side of the document G is defined as the surface of the document.

  The document reading unit 20 includes a contact image sensor (CIS: Contact Image Sensor) 29 as a second reading sensor in addition to the imaging unit 28 (first reading sensor). The CIS 29 reads the image on the back side of the document G as a second image. The CIS 29 is arranged on the conveyance path of the document G so as to read an image on the surface (the other surface) opposite to the one surface of the document on which an image is read by the imaging unit 28.

The paper transport unit 30 includes a second feed roller 31, a third feed roller 32, a registration roller pair 33, and a paper discharge unit 34. The second feed roller 31 supplies the paper T (image forming medium) stored in the paper feed cassette 36 to the transfer unit 50. The third feed roller 32 supplies the paper T (image forming medium) placed on the manual feed tray 37 to the transfer unit 50. The registration roller pair 33 carries the paper T or stops the conveyance of the paper T in order to match the timing at which the toner image is formed on the transfer unit 50 and the timing at which the paper T is supplied to the transfer unit 50. Further, the registration roller pair 33 performs skew (oblique feeding) correction of the paper T. The paper discharge unit 34 discharges the paper T on which the toner image is fixed to the outside of the copier body 2.
A paper discharge stacking unit 35 is formed outside the copier body 2 in the paper discharge unit 34. In the paper discharge stacking unit 35, the paper T discharged from the paper discharge unit 34 is stacked and stacked.

The image forming unit 40 includes a photosensitive drum 41, a charging unit 42, a laser scanner unit 43, a developing device 44, a cleaning unit 45, a toner cartridge 46, a primary transfer roller 47, and an intermediate transfer belt 48. And an opposing roller 49.
The photoconductor drum 41 (41a, 41b, 41c, 41d) functions as a photoconductor or an image carrier in order to form toner images of black, cyan, magenta, and yellow, respectively. Around each photosensitive drum 41a, 41b, 41c, 41d, in order from the upstream side to the downstream side along the rotational direction of the photosensitive drum 41, a charging unit 42, a laser scanner unit 43, a developing device 44, A cleaning unit 45 is disposed. The charging unit 42 charges the surface of the photosensitive drum 41. The laser scanner unit 43 is arranged away from the surface of the photosensitive drum 41 and scans and exposes the surface of the photosensitive drum 41 based on image data relating to the original G read by the original reading unit 20. As a result, the exposed portion of the charge is removed from the surface of the photosensitive drum 41 to form an electrostatic latent image. The developing device 44 forms a toner image by attaching toner to the electrostatic latent image formed on the surface of the photosensitive drum 41. The cleaning unit 45 removes toner and the like remaining on the surface of the photosensitive drum 41 after the surface of the photosensitive drum 41 is neutralized by a static eliminator (not shown).
The toner cartridge 46 stores toner of each color supplied to the developing device 44. The toner cartridge 46 and the developing device 44 are connected by a toner supply path (not shown).

  The primary transfer rollers 47 (47a, 47b, 47c, 47d) are arranged on the opposite sides of the intermediate transfer belt 48 from the photosensitive drums 41a, 41b, 41c, 41d, respectively. The intermediate transfer belt 48 is a belt that passes through the image forming unit 40 and the transfer unit 50. A part of the intermediate transfer belt 48 is sandwiched between the photosensitive drums 41a, 41b, 41c, and 41d and the primary transfer rollers 47a, 47b, 47c, and 47d, and the photosensitive drums 41a, 41b, 41c, and 41d. The toner image formed on the surface is primarily transferred. The counter roller 49 is a drive roller that is disposed inside the annular intermediate transfer belt 48 and advances the intermediate transfer belt 48 in the direction of arrow A shown in FIG.

  The transfer unit 50 includes a secondary transfer roller 51. The secondary transfer roller 51 is disposed on the opposite side of the intermediate transfer belt 48 from the counter roller 49, and a part of the intermediate transfer belt 48 is sandwiched between the counter roller 49. Further, the secondary transfer roller 51 secondarily transfers the toner image primarily transferred to the intermediate transfer belt 48 onto the paper T.

  The fixing unit 60 includes a heating rotator 61 and a pressure rotator 62. The heating rotator 61 and the pressure rotator 62 sandwich the paper T on which the toner image is secondarily transferred, melt and pressurize the toner, and fix the toner to the paper T.

Next, the functional configuration of the copy machine 1 will be described. FIG. 2 is a block diagram showing a functional configuration of the copy machine 1.
The copier 1 includes the above-described components (the document transport unit 10, the document reading unit 20, the paper transport unit 30, the image forming unit 40, the transfer unit 50, and the fixing unit 60). The engine unit 3 is configured by the paper transport unit 30, the image forming unit 40, the transfer unit 50, and the fixing unit 60. Note that the description of the components described with reference to FIG. 1 is omitted.
Further, the copier 1 includes an operation unit 70, a storage unit 80, and a control unit 90 in addition to the functional configuration described above.

  The operation unit 70 includes a numeric keypad (not shown), a touch panel 71 that also functions as a display unit, a start key (not shown), and the like. The numeric keypad is operated to input numbers such as the number of copies to be printed. The touch panel 71 displays a plurality of keys to which various functions (for example, a print magnification setting function and a function for allocating a plurality of pages to one sheet of paper T (such as 2 in 1)) are assigned. The keys displayed on the touch panel 71 are operated to cause the copier 1 to execute any of various functions. The start key is operated to execute printing. When any key is operated, the operation unit 70 supplies a signal indicating that this key has been operated to the control unit 90.

  The storage unit 80 includes a hard disk or a semiconductor memory. The storage unit 80 stores image data based on the document G read by the document reading unit 20. Further, the storage unit 80 stores a control program used in the copier 1, data used by the control program, and the like.

The control unit 90 controls the document conveying unit 10, the document reading unit 20, the engine unit 3, the operation unit 70, and the like.
The control unit 90 includes an inclination detection unit 91, a first determination unit 92, a second determination unit 93, a transport control unit 94, and a display control unit 95.

  The inclination detection unit 91 detects the inclination A1 of the document G based on the first image read by the imaging unit 28, and detects the inclination A2 of the document G based on the second image read by the CIS 29. . That is, the inclination detection unit 91 detects the inclination of the leading edge in the conveyance direction of the document G with respect to the main scanning direction orthogonal to the sub-scanning direction X (see FIG. 1). For example, the inclination detection unit 91 detects an angle [°] at which the document G is inclined.

As a more specific example, the inclination detection unit 91 extracts a document image area of a document part and a non-document image area that is not a document part from images read by the imaging unit 28 and the CIS 29, respectively, and the document image area And a non-document image area (a portion corresponding to the leading edge of the document G). Further, the inclination detecting unit 91 detects the obtained inclination of the boundary with respect to the main scanning direction.
The inclination detection unit 91 can detect the inclination of the document G based on the images read by the imaging unit 28 and the CIS 29 regardless of the size of the document G.

  The first determination unit 92 performs at least one of the first determination and the second determination. The first determination unit 92 detects, as the first determination, the inclination A1 of the document G detected by the inclination detection unit 91 based on the first image and the inclination detection unit 91 based on the second image. It is determined whether the inclination A2 of the original G is equal to or greater than a predetermined value. Further, the first determination unit 92 detects the inclination A1 of the document G detected by the inclination detection unit 91 based on the first image and the inclination detection unit 91 based on the second image as the second determination. It is determined whether the difference (A1−A2) from the inclination A2 of the original G is a predetermined value or more. Whether the difference (A1-A2) is equal to or greater than a predetermined value is determined by determining whether the inclination of the document G conveyed by the document conveying unit 10 has changed by a predetermined value or more during conveyance. Is.

For example, in the first determination, whether the inclination angle [°] of the original G based on the image (first image) read from the surface of the original G by the imaging unit 28 is equal to or larger than a predetermined inclination angle [°]. At the same time, it is determined whether the inclination angle [°] of the original G based on the image (second image) read from the back side of the original G by the CIS 29 is equal to or larger than the predetermined inclination angle [°]. Further, for example, in the second determination, the inclination angle [°] of the document G based on the image (first image) obtained by reading the front surface of the document G and the image (second image) obtained by reading the back surface of the document G. ) Based on the inclination angle [°] of the original G is determined to be equal to or larger than a predetermined value.
Here, the predetermined value in each of the first determination and the second determination is a value set as appropriate.
When the first determination unit 92 determines that the inclination is equal to or greater than a predetermined value or the difference is equal to or greater than the predetermined value, the first determination unit 92 determines that the document G conveyed by the document conveyance unit 10 is inclined. Become.

  The first determination unit 92 determines that the inclinations A1 and A2 of the original G (first original) conveyed first among the originals G placed on the original placement unit 11 are greater than or equal to a predetermined value, or In addition to determining whether the difference (A1-A2) between the inclinations A1 and A2 of the first document is greater than or equal to a predetermined value, the inclination of the document G conveyed after the first document is greater than or equal to a predetermined value. Or whether the difference in inclination of each image in the original G conveyed after the first original is equal to or greater than a predetermined value. For example, the first determination unit 92 determines whether the inclination of the second original conveyed next to the first original is equal to or greater than a predetermined value, or the difference in inclination between the images of the second original is equal to or greater than a predetermined value. Determine if there is.

  The second determination unit 93 performs the third determination when the first original as the original G and the second original as the original G to be conveyed next to the first original are conveyed by the original conveying unit 10. Do. As the third determination, the second determination unit 93 determines whether the difference between the first value and the second value is equal to or greater than a predetermined value. The first value is detected by the inclination detecting unit 91 based on the inclination A1 of the original G detected by the inclination detecting unit 91 based on the first image of the first original and the second image of the first original. And the difference (A1−A2) (first difference) from the inclination A2 of the original G. The second value is detected by the inclination detection unit 91 based on the inclination B1 of the original G detected by the inclination detection unit 91 based on the first image of the second original and the second image of the second original. The difference between the inclination B2 of the original G and the difference (B1-B2) (second difference).

For example, the first value is the inclination angle [°] of the original G based on the image (first image) on the front surface of the first original, and the original G based on the image (second image) on the back surface of the first original. Is the difference from the tilt angle [°]. Further, for example, the second value is based on the inclination angle [°] of the document G based on the image on the front surface of the second document (first image) and the image on the back surface of the second document (second image). This is the difference from the inclination angle [°] of the original G.
Here, the predetermined value in the third determination is a value set as appropriate.
The second determination unit 93 determines that the document G conveyed by the document conveyance unit 10 is tilted when it is determined that the difference between the first value and the second value is equal to or greater than a predetermined value. It will be.

  The second determination unit 93 not only determines whether the difference between the tilt difference based on each image of the first document and the tilt difference based on each image of the second document is equal to or greater than a predetermined value. Determining whether a difference between an inclination difference based on each image of the original G conveyed after the second original and an inclination difference based on each image of the original G conveyed immediately before is equal to or greater than a predetermined value. To do. For example, the second determination unit 93 determines that a difference between an inclination difference based on each image of the second original and an inclination difference based on each image of the third original conveyed next to the second original is equal to or greater than a predetermined value. It is determined whether it is.

  The conveyance controller 94 determines that the inclination of the original G detected based on the first image and the inclination of the original G detected based on the second image are equal to or greater than a predetermined value, respectively. Or the difference between the inclination of the original G detected based on the first image and the inclination of the original G detected based on the second image is equal to or greater than a predetermined value. When determined by the determination unit 92, the first control or the second control is performed according to a predetermined condition. That is, the conveyance control unit 94 controls the document conveyance unit 10 to stop conveyance of the next document G as the first control. Further, as the second control, the transport control unit 94 controls the document transport unit 10 to transport the next document G at a slower speed than the transport speed of the document G whose image has been read by the document reading unit 20.

  As a specific example, when the first document is conveyed by the document conveying unit 10, the conveyance control unit 94 determines that the inclinations A <b> 1 and A <b> 2 of the document G are greater than or equal to predetermined values by the first determination unit 92. If it is determined, or if the first determination unit 92 determines that the difference (A1-A2) in the inclination of the document G is greater than or equal to a predetermined value, the conveyance of the document G after the second document is stopped. The document transport unit 10 is controlled, or the document transport unit 10 is controlled so that the transport speed when transporting the second and subsequent documents G is slower than the transport speed when the first document is transported.

Here, when controlling the document transport unit 10 to stop the transport of the document G, the transport control unit 94 controls to stop driving the first feed roller 12 (see FIG. 1). Further, when controlling the conveyance speed of the original G to be reduced, the conveyance control unit 94 controls to decrease the rotation speed of the first feed roller 12.
The predetermined condition is a condition set in advance by the user as to which of the first control and the second control is performed.

  Further, the conveyance control unit 94 uses the second determination unit 93 to calculate the difference ((A1-A2)-(B1-B2)) between the first value (A1-A2) and the second value (B1-B2). When it is determined that the value is equal to or greater than the predetermined value, the third control or the fourth control is performed according to a predetermined condition. That is, the conveyance control unit 94 controls the document conveyance unit 10 to stop conveyance of the next document G following the second document as the third control. As the fourth control, the conveyance control unit 94 controls the document conveyance unit 10 to convey the next document G at a speed slower than the conveyance speed of the second document.

  As a specific example, the conveyance control unit 94 controls the document conveyance unit 10 to stop the conveyance of the document G after the third document following the second document as the third control. Further, as a fourth control, the transport control unit 94 controls the document transport unit 10 so that the transport speed when transporting the third and subsequent documents G is slower than the transport speed when the second document is transported. Control.

Here, when controlling the document transport unit 10 to stop the transport of the document G, the transport control unit 94 controls to stop driving the first feed roller 12 (see FIG. 1). Further, when controlling the conveyance speed of the original G to be reduced, the conveyance control unit 94 controls to decrease the rotation speed of the first feed roller 12.
The predetermined condition is a condition set in advance by the user as to which of the third control and the fourth control is performed.

  The display control unit 95 determines that the document transport unit 10 is controlled by the transport control unit 94 to stop the transport of the next document G and the transport speed of the document G from which the image is read by the document reading unit 20. When the document transport unit 10 is controlled by the transport control unit 94 to transport the next document G at a later time, a warning is displayed on the touch panel 71. The warning display is a display indicating that the conveyance of the original G is stopped when the conveyance of the original G is stopped. The warning display is a display indicating that when the conveyance speed of the document G is decreased, the conveyance speed of the document G is decreased.

  Next, the operation of the copy machine 1 will be described. FIG. 3 is a flowchart for explaining the operation of the copying machine 1.

  In step ST1, the document conveying unit 10 conveys the first document G (first document) placed on the document placing unit 11 to the first reading surface 21a.

  In step ST <b> 2, the inclination detection unit 91 detects the inclination A <b> 1 of the original G based on the image on the front surface of the first original read by the imaging unit 28, and converts the image on the back side of the first original read by the CIS 29. Based on this, the inclination A2 of the original G is detected.

  Here, a large-size original G (for example, an A3-size original G) and a small-size original G (for example, an A5-size original G) are mixedly placed on the original placement unit 11, and the original conveyance unit 10 When transporting these originals G to the first reading surface 21a, particularly when transporting a small-size original G, the original G is inclined and easily transported. For this reason, in step ST2, the inclination of the original G is detected.

  In step ST3, the first determination unit 92 determines whether the inclinations A1 and A2 of the original G detected in step ST2 are equal to or larger than predetermined values, or the difference (A1) in the inclination of the original G detected in step ST2. -Determine whether A2) is greater than or equal to a predetermined value. If the slope A1, A2 or the difference (A1-A2) is greater than or equal to a predetermined value (Yes), the process proceeds to step ST4. If the slopes A1 and A2 and the difference (A1-A2) are not equal to or greater than the predetermined value (No), the process proceeds to step ST9.

  In step ST4, the conveyance control unit 94 determines whether to control the document conveyance unit 10 to stop conveyance of the second document. If the document conveying unit 10 is controlled to stop conveying the second document (Yes), the process proceeds to step ST5. If the document transport unit 10 is not controlled to stop the transport of the second document (No), the process proceeds to step ST7.

  In step ST <b> 5, the display control unit 95 causes the touch panel 71 to display a warning indicating that the conveyance of the document G is to be stopped.

  In step ST <b> 6, the conveyance control unit 94 controls the document conveyance unit 10 to stop the conveyance of the document G. That is, the conveyance control unit 94 stops driving the first feed roller 12 so as not to convey the second document.

  On the other hand, if “No” is determined in step ST4, in step ST7, the display control unit 95 causes the touch panel 71 to display a warning indicating that the conveyance speed of the document G is to be decreased.

  In step ST8, the display control unit 95 sets a warning flag indicating that the conveyance speed of the document G is to be lowered to ON.

  In step ST9, the conveyance control unit 94 determines whether or not the warning flag is turned on. If the warning flag is on (Yes), the process proceeds to step ST10. If the warning flag is not turned on (No), the process proceeds to step ST12.

  In step ST <b> 10, the conveyance control unit 94 determines whether or not the conveyance speed of the document G has already been reduced by controlling the document conveyance unit 10. If the conveyance speed of the original G is not slowed (No), the process proceeds to step ST11. If the conveyance speed of the document G has already been reduced (Yes), the process proceeds to step ST12.

  In step ST <b> 11, the conveyance control unit 94 controls the document conveyance unit 10 to make the conveyance speed when conveying the next document G slower than the conveyance speed when conveying the document G immediately before.

  In step ST12, the document conveying unit 10 conveys the next document G (second and subsequent documents G (second and subsequent documents)) placed on the document placing unit 11 to the first reading surface 21a.

  In step ST <b> 13, the inclination detection unit 91 detects the inclination B <b> 1 of the original G based on the image of the front surface of the next original G read by the imaging unit 28, and also detects the inclination of the back side of the next original G read by the CIS 29. The inclination B2 of the original G is detected based on the image.

  In step ST14, the first determination unit 92 determines whether the inclinations B1 and B2 of the next original G detected in step ST13 are greater than or equal to predetermined values, respectively, or the inclination of the next original G detected in step ST13. It is determined whether the difference (B1-B2) is greater than or equal to a predetermined value. If the slopes B1, B2 and the difference (B1-B2) are not greater than or equal to a predetermined value (No), the process proceeds to step ST15. If the slope B1, B2 or the difference (B1-B2) is greater than or equal to a predetermined value (Yes), the process proceeds to step ST16.

  In step ST15, the second determination unit 93 determines the difference in inclination (here, (A1-A2)) of the document G conveyed immediately before and the difference in inclination of the next document G conveyed in step ST12 (here, It is determined whether the difference ((A1-A2)-(B1-B2)) from (B1-B2)) is equal to or greater than a predetermined value. If the difference ((A1-A2)-(B1-B2)) is greater than or equal to a predetermined value (Yes), the process proceeds to step ST16. If the difference ((A1-A2)-(B1-B2)) is not greater than or equal to a predetermined value (No), the process proceeds to step ST19.

  In step ST16, the conveyance control unit 94 determines whether to control the document conveyance unit 10 to stop conveyance of the next document G (third and subsequent documents) conveyed after the document G conveyed in step ST12. To do. If the document conveying unit 10 is controlled to stop conveying the next document G (Yes), the process returns to step ST5. If the original conveyance unit 10 is not controlled to stop the conveyance of the next original G (No), the process proceeds to step ST17.

  In step ST <b> 17, the display control unit 95 causes the touch panel 71 to display a warning indicating that the conveyance speed of the document G is to be decreased.

  In step ST18, the display control unit 95 sets a warning flag indicating that the conveyance speed of the document G is to be lowered to ON.

  In step ST <b> 19, the document transport unit 10 determines whether or not the document G to be transported remains on the document stacking unit 11. If document G remains (Yes), the process returns to step ST9. If the document G does not remain (No), the process ends.

As described above, according to the copying machine 1 of the present embodiment, the following effects are produced.
That is, in the copier 1 of the present embodiment, the inclination of the original G detected based on the first image and the inclination of the original G detected based on the second image are each equal to or greater than a predetermined value. When the determination is made by the first determination unit 92, or the difference between the inclination of the original G detected based on the first image and the inclination of the original G detected based on the second image is equal to or greater than a predetermined value. If the first determination unit 92 determines that the next original G is stopped, the conveyance of the next original G is stopped or the original reading speed of the original G from which the image is read by the original reading unit 20 is reduced. G is conveyed. As a result, in the copying machine 1, in addition to the case where only one type of document G is placed on the document placement unit 11, the large document G and the small document G are placed on the document placement unit 11. Even when they are mixedly loaded, the inclination of each original G can be determined. Further, when it is determined that the original G is inclined, the copying machine 1 stops the conveyance of the original G or slows down the conveyance speed of the original G. Therefore, there is a possibility that the original G is jammed. The possibility of damaging the original G can be reduced.

  Further, in the copying machine 1 according to the present embodiment, the conveyance control unit 94 causes the second determination unit 93 to determine a difference between the first value (first difference) and the second value (second difference). When it is determined that the value is equal to or greater than the value, the conveyance of the next original G following the second original is stopped, or the next original G is conveyed slower than the conveyance speed of the second original. As a result, when it is determined that the document G is tilted, the copying machine 1 stops the conveyance of the document G or slows the conveyance speed of the document G, so that the document G may be jammed. The possibility of damaging the original G can be reduced.

  Further, the copying machine 1 according to the present embodiment conveys the next original G when the conveyance of the next original G is stopped and at a slower speed than the conveyance speed of the original G whose image is read by the original reading unit 20. When doing so, a warning is displayed on the display unit. Thereby, the copying machine 1 can notify the user that the conveyance of the original G has been stopped and the conveyance speed of the original G has been reduced.

In addition, this invention is not limited to embodiment mentioned above, It can implement with a various form.
In the above-described embodiment, the case where the first reading sensor is the imaging unit 28 including an image sensor such as a CCD or a CMOS and the second reading sensor is the CIS 29 has been described. However, the present invention is not limited to this form and may take other forms. That is, there are no restrictions on the types and positions of the first reading sensor and the second reading sensor.
In addition, the document transport unit 10 according to the present embodiment is configured to discharge the document G whose image is read on the first reading surface 21 a to the document stacking unit 16 without inverting the document G. However, the present invention is not limited to this configuration, and the front and back sides of the document whose surface is read on the first reading surface are reversed and supplied to the first reading surface again, and the image on the back surface of the document G is displayed. May be configured to read.

The copying machine 1 according to the present embodiment is a color copying machine, but is not limited to this mode, and may be a monochrome copying machine.
In the copying machine 1 of the present embodiment, the toner image is transferred to the paper T via the intermediate transfer belt 48 (indirect transfer method). However, the present invention is not limited to this form, and is formed on the photosensitive drum. The transferred toner image may be directly transferred to the paper T (direct transfer method).
The copier 1 of the present embodiment is configured to print one side of the paper T, but is not limited to this, and may be configured to print both sides of the paper.

Further, the image forming apparatus of the present invention is not limited to the copying machine 1 described above. In other words, the image forming apparatus of the present invention may be a multi-function machine having a copy function, a facsimile function, a printer function, and a scanner function, or may be a facsimile or a printer.
The image forming medium on which the toner image is fixed by the image forming apparatus of the present invention is not limited to the paper T, and may be a film sheet such as an OHP (overhead projector) sheet.

DESCRIPTION OF SYMBOLS 1 ... Copy machine (image forming apparatus), 10 ... Document conveyance part, 20 ... Document reading part, 28 ... Imaging part (1st reading sensor), 29 ... Contact-type image sensor (2nd reading sensor), 71 ... Touch panel ( Display unit), 90 ... Control unit, 91 ... Inclination detection unit, 92 ... First determination unit, 93 ... Second determination unit, 94 ... Transport control unit, 95 ... Display control unit

Claims (6)

A document reading unit having a first reading sensor that reads an image on the front side of the document as a first image, and a second reading sensor that reads an image on the back side of the document as a second image;
A document transport unit that transports a document to the document reading unit;
An inclination detection unit that detects the inclination of the document based on the first image read by the first reading sensor and detects the inclination of the document based on the second image read by the second reading sensor; ,
The document inclination detected by the inclination detection unit based on the first image and the document inclination detected by the inclination detection unit based on the second image are each equal to or greater than a predetermined value; and The difference between the inclination of the document detected by the inclination detection unit based on the first image and the inclination of the document detected by the inclination detection unit based on the second image is greater than or equal to a predetermined value. A first determination unit that performs at least one of the determinations;
When the first determination unit determines that the inclination of the document detected based on the first image and the inclination of the document detected based on the second image are equal to or greater than a predetermined value, or When the first determination unit determines that the difference between the inclination of the document detected based on the first image and the inclination of the document detected based on the second image is equal to or greater than a predetermined value , A conveyance control unit that controls the document conveyance unit to stop conveyance of the next document;
An image forming apparatus comprising: When a first document as a document and a second document as a document transported next to the first document are transported by the document transport unit,
By the inclination detecting unit, a is the difference between the first and the slope of the detected document based on the image, the first second of the slope of the detected document based on the image of the document in the first document The difference of 1 and
By the inclination detecting unit, a is the difference between the first and the slope of the detected document based on the image, the second second slope of the detected document based on the image of the document of the second document A second determination unit that determines whether the difference between the two differences is equal to or greater than a predetermined value;
The transfer control unit, when the difference between the second difference and the first difference by the second determination unit is determined to be equal to or greater than a predetermined value, the next document following the second document The image forming apparatus according to claim 1, wherein the document conveying unit is controlled to stop conveyance. A display unit;
A display control unit for displaying a warning on the display unit when the document transport unit is controlled by the transport control unit to stop transport of a next document;
The image forming apparatus according to claim 1, further comprising: A document reading unit having a first reading sensor that reads an image on the front side of the document as a first image, and a second reading sensor that reads an image on the back side of the document as a second image;
A document transport unit that transports a document to the document reading unit;
An inclination detection unit that detects the inclination of the document based on the first image read by the first reading sensor and detects the inclination of the document based on the second image read by the second reading sensor; ,
The document inclination detected by the inclination detection unit based on the first image and the document inclination detected by the inclination detection unit based on the second image are each equal to or greater than a predetermined value; and The difference between the inclination of the document detected by the inclination detection unit based on the first image and the inclination of the document detected by the inclination detection unit based on the second image is greater than or equal to a predetermined value. A first determination unit that performs at least one of the determinations;
When the first determination unit determines that the inclination of the document detected based on the first image and the inclination of the document detected based on the second image are equal to or greater than a predetermined value, or When the first determination unit determines that the difference between the inclination of the document detected based on the first image and the inclination of the document detected based on the second image is equal to or greater than a predetermined value, A transport control unit that controls the document transport unit to transport the next document at a slower speed than the transport speed of the document whose image has been read by the document reading unit;
An image forming apparatus comprising: When a first document as a document and a second document as a document transported next to the first document are transported by the document transport unit,
A difference between the inclination of the original detected by the inclination detection unit based on the first image of the first original and the inclination of the original detected based on the second image of the first original. 1 difference
When,
A difference between the inclination of the original detected by the inclination detection unit based on the first image of the second original and the inclination of the original detected based on the second image of the second original. Difference of two
A second determination unit that determines whether or not the difference between the first and second values is equal to or greater than a predetermined value,
The conveyance control unit is slower than the conveyance speed of the second document when the second determination unit determines that the difference between the first difference and the second difference is equal to or greater than a predetermined value. To control the document conveying section to convey the next document.
The image forming apparatus according to claim 4. A display unit;
When the document transport unit is controlled by the transport control unit to transport the next document at a slower speed than the transport speed of the document whose image has been read by the document reading unit, a warning is displayed on the display unit. A display control unit,
An image forming apparatus according to claim 4 or 5.

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