JP7002001B2 - Sheet detection device, transfer device, image forming device, sheet detection position adjustment method - Google Patents

Description

The present invention relates to a sheet detection device, a transfer device, an image forming device, and a method for adjusting a sheet detection position.

Conventionally, there has already been a device capable of detecting a positional deviation such as a tilting of a sheet or a positional deviation in the width direction by providing a detection mechanism for detecting the edge of the sheet.

For example, an image forming apparatus that forms an image on a sheet is provided with a detection mechanism and a transfer member that conveys the sheet and corrects the positional deviation of the sheet based on the detection result of the detection mechanism, and positions the sheet during sheet transfer. An invention has been made to detect and correct a deviation (for example, Patent Document 1).

The transport device of Patent Document 1 (Japanese Unexamined Patent Publication No. 2016-175776) includes three detection mechanisms for detecting the positional deviation of the sheet in the sheet transport direction, the first CIS, the second CIS, and the third CIS. A holding roller is provided, which corrects the misalignment of the seat and conveys it to the downstream side. Then, the sandwiching roller corrects the seat position deviation based on the seat position detection results by the first CIS and the second CIS, and then the seat position deviation based on the seat detection results by the second CIS and the third CIS. Is corrected again. By correcting the sheet for which the position deviation has been corrected in this way again, the position deviation of the sheet can be corrected with high accuracy.

In a configuration in which the position of the seat is detected by a plurality of detection mechanisms as in Patent Document 1, a detection error between the detection mechanisms becomes a problem. For example, if any of the detection mechanisms is displaced from the normal position, the displacement will directly lead to the detection error of the sheet, and a detection error will occur with the other detection mechanism. It ends up.

There is a problem that the position detection accuracy of the sheet is lowered due to the detection error between the detection mechanisms. In particular, as in Patent Document 1, in the case of a configuration in which the position deviation detection operation for the first correction of the sheet and the position deviation detection operation for re-correction are performed based on the detection results of different combinations of detection mechanisms. Because an error occurs between the respective detection results, the target position after correction cannot be unified between the first correction operation and the re-correction operation, or a useless correction operation occurs.

From such a problem, it is an object of the present invention to provide a sheet detection device capable of adjusting detection results between detection mechanisms.

In order to solve the above problems, the present invention has a plurality of sensors arranged side by side in the width direction of the seat, and a first detection mechanism, a second detection mechanism, capable of detecting the position of the seat by the plurality of sensors. And, using the detection result of any two of the third detection mechanism, the first detection mechanism, the second detection mechanism, and the third detection mechanism, the sheet or the jig, the sheet or the jig A seat detection device including a control unit capable of calculating the amount of skew of the first detection mechanism, the second detection mechanism, and the third detection mechanism are the width of the seat. The jig is arranged side by side in a direction orthogonal to the direction and in a direction different from the thickness direction of the sheet, and the jig is arranged so as to face the first detection mechanism, the second detection mechanism, and the third detection mechanism . The first detection mechanism for detecting the position of the sheet or the jig is performed by the detection mechanism and the second detection mechanism, and the position of the sheet or the jig is detected by the second detection mechanism and the third detection mechanism. The first detection mechanism, the second detection mechanism, and the second detection mechanism, according to the skew amount of the jig calculated by the control unit using the detection results of the first detection and the second detection after performing the second detection. Further, it is characterized in that the detection position of the sheet detected by at least one of the third detection mechanisms is adjusted .

In the present invention, the detection result of the jig can be adjusted by using the detection result of the jig by each detection mechanism, and the detection error between the detection mechanisms can be adjusted.

It is a schematic block diagram of an image forming apparatus. It is a figure which shows the structure of the transfer apparatus which concerns on embodiment of this invention, (a) is a plan view, (b) is a side view. It is a figure which shows the transport process by a transport device, (a) is a plan view, (b) is a side view. It is a figure which shows the transport process by a transport device, (a) is a plan view, (b) is a side view. It is a figure which shows the transport process by a transport device, (a) is a plan view, (b) is a side view. It is a figure which shows the transport process by a transport device, (a) is a plan view, (b) is a side view. It is a figure which shows the transport process by a transport device, (a) is a plan view, (b) is a side view. It is a figure explaining the calculation method of the position deviation amount. It is a figure which shows the flow which conveys and corrects the paper of a transfer apparatus. It is a top view which shows the jig used for the adjustment mode, and the arrangement thereof. It is a figure which shows the calculation method of the adjustment value. It is a flow chart of an adjustment mode. It is a figure which shows the calculation method of the position deviation amount using the adjustment value. It is a flow chart which shows the calculation method of the position deviation amount using the adjustment value at the time of the 1st detection operation. It is a flow chart which shows the calculation method of the position deviation amount using the adjustment value at the time of a re-correction operation. It is a figure explaining the shape error of a jig. It is a block diagram which shows the control part of the transporting apparatus which concerns on this embodiment. It is a figure which shows the opening and closing operation of a transfer device, (a) is a side view which shows the closing time, (b) is a side view which shows the opening time. It is a schematic block diagram which shows the image forming apparatus of a different embodiment. It is a schematic diagram which shows the structure which applied the transfer apparatus which concerns on this invention to the post-processing apparatus.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In each figure, the same or corresponding parts are designated by the same reference numerals, and the duplicated description thereof will be appropriately simplified or omitted.

The color image forming apparatus 1 shown in FIG. 1 is provided with an image forming unit 3 to which four process units 9Y, 9M, 9C, and 9Bk are detachably provided. Each process unit 9Y, 9M, 9C, 9Bk accommodates developers of different colors of yellow (Y), magenta (M), cyan (C), and black (Bk) corresponding to the color separation components of the color image. It has the same configuration except that it is.

Specific process units 9 include a photoconductor drum 10 which is a drum-shaped rotating body capable of supporting toner as a developer on the surface, and a charging roller 11 which uniformly charges the surface of the photoconductor drum 10. It also includes a developing device 12 that supplies toner to the surface of the photoconductor drum 10, a cleaning device, and the like.

An exposure unit is arranged above the process unit 9. The exposed unit is configured to emit laser light based on the image data.

The transfer unit 4 is arranged directly below the image-creating unit 3. The transfer unit 4 includes a drive roller 13, a secondary transfer facing roller 15, a plurality of tension rollers, an endless intermediate transfer belt 16 stretched by these rollers so as to be able to travel around, and a photoconductor drum of each process unit 9. It is composed of a primary transfer roller 17 or the like arranged at a position facing the intermediate transfer belt 16 with respect to 10. Each primary transfer roller 17 presses the inner peripheral surface of the intermediate transfer belt 16 at each position, and a primary transfer nip is formed at a position where the pressed portion of the intermediate transfer belt 16 and each photoconductor drum 10 come into contact with each other. Has been done.

Further, the drive roller 13 of the intermediate transfer belt 16 and the secondary transfer roller 18 are arranged at positions facing the drive roller 13 with the intermediate transfer belt 16 interposed therebetween. The secondary transfer roller 18 presses the outer peripheral surface of the intermediate transfer belt 16, and a secondary transfer nip is formed at a position where the secondary transfer roller 18 and the intermediate transfer belt 16 come into contact with each other.

The paper feed unit 5 is located at the lower part of the image forming apparatus 1, and is a paper feed cassette 19 as a sheet loading unit that accommodates the paper P as a sheet, and a paper feed roller that carries out the paper P from each paper feed cassette. It consists of 20 mag.

The transport path 6 is a transport path for transporting the paper P carried out from the paper feeding unit 5. A plurality of transport roller pairs are appropriately arranged on the transport path 6 up to the paper ejection portion described later.

On the transport path 6, on the downstream side in the paper transport direction from the paper feed unit 5, and on the upstream side from the secondary transfer nip position, the misalignment of the paper P on the transport path 6 is corrected, and the paper P is moved to the downstream side. A transport device 30 for transport is provided.

The fixing device 7 has a fixing roller 22 heated by a heating source, a pressure roller 23 capable of pressurizing the fixing roller 22, and the like.

The paper ejection unit 8 is provided at the most downstream side of the transport path 6 of the image forming apparatus 1. The paper ejection unit 8 is provided with a pair of paper ejection rollers 24 for ejecting the paper P to the outside and a paper ejection tray 25 for stocking the ejected paper P.

The transport path 6 is provided with an inverted transport path 6a that divides the flow downstream of the fixing device 7, in addition to the path leading to the paper ejection unit 8. The inverted transport path 6a joins the transport path 6 continuing from the paper feed section 5 at the end thereof.

Further, a scanner unit 2 for reading an image formed on paper is arranged above the image forming apparatus 1.

Hereinafter, the basic operation of the image forming apparatus 1 will be described with reference to FIG.

When the image forming operation is started in the image forming apparatus 1, an electrostatic latent image is formed on the surface of the photoconductor drum 10 of each process unit 9Y, 9C, 9M, 9Bk. The image information exposed by the exposure unit on each photoconductor drum 10 is monochromatic image information obtained by decomposing a desired full-color image into yellow, cyan, magenta, and black color information. An electrostatic latent image is formed on each photoconductor drum 10, and the toner stored in each developing device is supplied to the photoconductor drum 10 by a drum-shaped developing roller, so that the electrostatic latent image is visualized. It is visualized as a toner image (developer image).

In the transfer unit 4, the intermediate transfer belt 16 is driven to travel in the direction of the arrow in the figure by the rotational drive of the drive roller 13. Further, a constant voltage or a constant current controlled voltage having a polarity opposite to the charging polarity of the toner is applied to each primary transfer roller 17. As a result, a transfer electric field is formed at the primary transfer nip, and the toner images formed on each photoconductor drum 10 are sequentially superposed on the intermediate transfer belt 16 at the primary transfer nip and transferred. As described above, for example, the image forming unit 3, the exposure unit, the transfer unit 4, and the like function as an image forming unit that forms an image on the paper P.

On the other hand, when the image forming operation is started, in the lower part of the image forming apparatus 1, the paper feeding roller 20 of the paper feeding unit 5 is rotationally driven, so that the paper P accommodated in the paper feeding cassette 19 is moved to the transport path 6. Be sent out.

The paper P sent out to the transport path 6 is transported to the downstream side by the transport device 30 and the roller pair on the transport path 6, and the misalignment is corrected by the transport device 30, so that the secondary transfer roller 18 and the secondary transfer roller 18 are secondary. It is sent to the secondary transfer nip formed between the transfer facing roller 15. At this time, a transfer voltage having a polarity opposite to the toner charging polarity of the toner image on the intermediate transfer belt 16 is applied, and a transfer electric field is formed in the secondary transfer nip. The toner image on the intermediate transfer belt 16 is collectively transferred onto the paper P by the transfer electric field formed in the secondary transfer nip.

The paper P on which the toner image is transferred is conveyed to the fixing device 7, and the paper P is heated and pressed by the fixing roller 22 and the pressure roller 23 to fix the toner image on the paper P. Then, the paper P on which the toner image is fixed is separated from the fixing roller 22, is conveyed by the transport roller pair, and is ejected to the output tray 25 by the output roller 24 at the paper ejection unit 8.

When double-sided printing is performed on the paper P, the paper P is conveyed to the paper ejection roller 24, and the paper ejection roller 24 rotates in the reverse direction until the rear end of the paper P passes through the paper ejection roller 24, and the paper is printed. P is conveyed in the opposite direction and sent out to the reverse transfer path 6a. After that, the paper P is conveyed on the reverse transfer path 6a by the reverse transfer roller, and is fed to the upstream side of the transfer device 30 of the transfer path 6 again in a state of being turned upside down. Then, after the positional deviation of the paper P is corrected by the transport device 30, the image is transferred and fixed on the back surface, and the paper P is discharged to the paper output tray 25 by the paper discharge roller 24.

The above description is an image forming operation when forming a full-color image on paper P, but a single-color image can be formed by using any one of four process units 9Y, 9C, 9M, and 9Bk. It is also possible to use two or three process units 9 to form a two-color or three-color image.

As shown in FIGS. 2 (a) and 2 (b), the transport device 30 of the present embodiment includes a transport roller 31, a sandwiching roller (conveyor member) 32, a sheet detection device 70, and a first edge for transporting paper P. It has a sensor 37, a second edge sensor 38, a third edge sensor 39, and a fourth edge sensor 40. The sheet detection device 70 is a first CIS (first detection mechanism) 34 and a second CIS (second detection mechanism) for detecting the position of the paper P, which are three detection mechanisms arranged side by side on the transport path 6. ) 35 and a third CIS (third detection mechanism) 36. Hereinafter, the transport direction of the paper P is simply referred to as a transport direction, and the upstream side and the downstream side in the transport direction are also simply referred to as an upstream side and a downstream side. Further, the width direction of the paper P is also simply referred to as the width direction. The paper transport direction is a direction orthogonal to the paper width direction and different from the paper thickness direction.

The transfer roller 31 and the sandwiching roller 32 are transfer rollers composed of a pair of rollers. These rollers can convey the paper P to the downstream side by rotationally driving each roller pair in a state where the paper P is sandwiched between the nip portions of the rollers. The holding roller 32 is provided on the downstream side of the transport roller 31 in the transport direction of the paper P. Further, a secondary transfer roller 18 is provided on the downstream side of the holding roller 32.

The sandwiching roller 32 is provided so as to be rotatable around the fulcrum 32a in the paper transport surface and movable in the width direction. By these operations, the sandwiched paper P can be rotated or moved in the width direction, and the skewing or the positional deviation in the width direction of the paper P can be corrected. Hereinafter, with respect to the sandwiching roller 32, the rotation of the roller for transporting the paper P is simply described as the rotation, and the rotation for skew correction is described separately from the rotation in the paper transport surface.

In each CIS of the first CIS34, the second CIS35, and the third CIS36, a contact image in which a plurality of photosensors composed of a light emitting element such as an LED and a light receiving element such as a photodiode are arranged side by side in the width direction of the paper P. It is a sensor.

The first edge sensor 37, the second edge sensor 38, the third edge sensor 39, and the fourth edge sensor 40 are sensors capable of detecting the position of the front end or the rear end of the paper P. As these sensors, for example, a pair of photosensors including a light emitting element and a light receiving element can be used.

The first edge sensor 37 is provided in the vicinity of the downstream side of the transport roller 31. The second edge sensor 38 is provided in the vicinity of the upstream side of the second CIS 35. A third edge sensor 39 is provided in the vicinity of the downstream side of the pinching roller 32. The fourth edge sensor 40 is provided near the downstream side of the secondary transfer roller 18.

Next, for each basic operation of the process in which the transport device 30 corrects the positional deviation while transporting the paper P, the operation diagrams of FIGS. 2 to 7, the flow charts of FIGS. 8 and 9, are shown. It will be explained using.

First, as shown in FIGS. 2A and 2B, the paper P conveyed to the transfer device 30 reaches the first CIS 34 and then the transfer roller 31. Then, the paper P is sandwiched between the transport rollers 31 and transported to the downstream side. At this time, the transport member on the upstream side of the transport device 30 (in this embodiment, the roller pair 26 on the upstream side in FIG. 1) is separated from the paper P.

The paper P conveyed to the transfer device 30 is conveyed by the transfer roller 31 (step S1 in FIG. 9). Then, as shown in FIGS. 2 (a) and 2 (b), the paper P reaches the first CIS 34. The paper P reaches the first edge sensor 37 immediately before reaching the first CIS 34, and the arrival is detected. In this way, the first edge sensor 37 can detect the timing at which the paper P reaches the first CIS 34.

When the paper P is conveyed further downstream, the paper P reaches the second CIS35 (step S2), as shown in FIGS. 3 (a) and 3 (b). When the paper P reaches the second CIS35, the position of the paper P is detected by the first CIS34 and the second CIS35, and the position deviation amount and the skew amount in the width direction are calculated (step S3).

The paper P reaches the second edge sensor 38 immediately before reaching the second CIS 35, and the arrival is detected. In this way, the second edge sensor 38 can detect the timing at which the paper P reaches the second CIS35, and at this timing, the first CIS34 and the second CIS35 detect the paper P (first detection operation). Can be started.

An example of a method of calculating the skew amount and the position deviation amount in the width direction of the paper P based on the detection results by the first CIS34 and the second CIS35 will be described with reference to FIG.
As shown in FIG. 8, since the boundary between the paper portion and the non-paper portion can be detected by the first CIS34 and the second CIS35, the position in the width direction of the side edge Pa of the paper P can be detected. Specifically, the first CIS34 can detect the widthwise position X1 of the point Pa1, and the second CIS35 can detect the widthwise position X2 of the point Pa2. The amount of positional deviation of the paper P in the width direction can be obtained as the distance from the ideal width direction position X0 of the paper P to the points Pa1 and Pa2, or as an average value thereof. Further, the inclination angle (inclination amount) θ1 of the paper P is determined by using the distance M between the first CIS34 and the second CIS35 in the transport direction.
TANθ1 = (X1-X2) / M ... (1)
It can be expressed as. The skew amount θ1 of the paper P can be obtained from this equation (1).

Then, the holding roller 32 performs the picking operation based on the position deviation amount and the skew amount in the width direction of the paper P calculated by the first detection operation (step S4). The pick-up operation is an operation in which the holding roller 32 moves from the reference position by the amount of the positional deviation in the skewing direction of the paper P and the positional deviation direction in the width direction. In other words, the pinching roller 32 is an operation of moving so as to receive the paper P facing the misaligned paper P, and the pinching roller 32 moves from the dotted line portion of FIG. 3A as shown by the solid line portion. It is an operation. The reference position of the pinching roller 32 is a position where the pinching roller 32 is arranged on the transport path 6 so as to face the transport path 6 (see FIG. 2a).

When the paper P is further transported to the downstream side, the paper P reaches the holding roller 32 as shown in FIGS. 4 (a) and 4 (b) (step S5). The paper P is sandwiched by the sandwiching roller 32 and further conveyed to the downstream side. Further, at this time, the transport roller 31 is separated from the paper P. In the present embodiment, as shown in FIG. 4B, of the roller pairs of the transport rollers 31, only the upper roller is separated from the transport path 6. The same operation is performed when the sandwiching roller 32 is separated from the transport path 6.

As shown in FIGS. 5A and 5B, the holding roller 32 is rotationally driven to convey the paper P further to the downstream side. Further, in parallel with this transport operation, the pinching roller 32 performs a return operation, which is an operation for correcting the positional deviation of the paper P (step S6). The return operation is an operation of correcting the misalignment of the paper P by rotating the paper P in the transport surface and moving it in the width direction by the amount of the misalignment of the paper P during the transport operation of the paper P. , The operation of the sandwiching roller 32 in FIG. 5A is to move from the dotted line portion to the solid line portion. The correction amount is the position deviation amount calculated in step S3. Further, the holding roller 32 after the return operation returns to the reference position.

After the process of the return operation or the completion of the return operation, the paper P reaches the third edge sensor 39, and the arrival is detected. Then, as shown in FIGS. 6A and 6B, after the paper P reaches the third edge sensor 39, the paper P reaches the third CIS36 (step S7). In this way, by detecting the paper P by the third edge sensor 39, it is possible to detect the timing at which the paper P reaches the third CIS36, and at this timing, the paper detection operation by the second CIS35 and the third CIS36. (Second detection operation) can be started.

When the paper P reaches the third CIS36, the position of the paper P is detected again by the second CIS35 and the third CIS36, and the misalignment amount of the paper P is calculated (step S7). Then, the positional deviation of the paper P is corrected again by the rotational operation of the holding roller 32 in the transport surface and the movement operation in the width direction (step S8). The method of calculating the amount of misalignment of the paper P based on the detection results of the second CIS35 and the third CIS36 is the same as the detection method by the first CIS34 and the second CIS35 described above.

From the time when the paper P reaches the third CIS36 until it reaches the downstream roller (secondary transfer roller 18 in this embodiment), the position of the paper P is detected and the amount of misalignment is calculated by the second CIS35 and the third CIS36. The operation and the correction operation by the holding roller 32 are repeated. That is, the position shift amount calculated by the detection results of the second CIS35 and the third CIS36 is fed back to the holding roller 32 each time, and the position shift of the paper P is corrected with high accuracy.

Then, as shown in FIGS. 7 (a) and 7 (b), the paper P reaches the secondary transfer position (step S9). The image of the paper P is transferred at the secondary transfer position in a state where the positional deviation is corrected.

When the paper P reaches the secondary transfer position, the paper P is detected by the fourth edge sensor 40 provided downstream of the secondary transfer roller 18. As a result, it is detected that the paper P transporting operation and the misalignment correction operation by the transporting device 30 are completed, and the holding roller 32 shifts to the preparatory operation for transporting the next paper P. Specifically, the sandwiching roller 32 is separated from the transport path 6 and returns to the reference position.

When the paper P1 conveyed to the secondary transfer roller 18 is the last sheet, the transfer operation by the transfer device 30 is completed by returning to the reference position of the holding roller 32 (step S10). Further, when the next paper P2 is conveyed, the conveying operation of the paper P2 is restarted.

As described above, the transport device 30 can transport the paper P to the downstream side and correct the misalignment of the paper P by the first correction operation (return operation) and the re-correction operation by the holding roller 32.

By the way, when each CIS is mounted so as to be displaced from the regular position, an error in the mounting position leads to a detection error when the paper P is detected. If there is this detection error, a detection error will occur between the first detection by the first CIS34 and the second CIS35 and the second detection by the second CIS35 and the third CIS36. Due to this detection error, even if the position deviation amount is corrected by the first correction operation based on the detection result by the first detection operation, the detection error amount is detected as the position deviation amount at the time of the second detection. This may lead to an increase in the amount of correction during the re-correction operation, or the target position for paper correction cannot be unified between the first correction operation and the re-correction operation.

Therefore, in the present embodiment, the detection error between each CIS is corrected by adjusting the detection result of each CIS using the jig 50. Hereinafter, the details of the adjustment mode using the jig 50 will be described.

As shown in FIG. 10, the jig 50 is arranged with its side end 50a facing the first CIS34, the second CIS35, and the third CIS36. In other words, the jig 50 is arranged at a position where each CIS can detect its side end 50a. Hereinafter, this position is referred to as an adjustment position of the jig 50. The jig 50 is provided with a length in the transport direction longer than the separation distance A between the first CIS 34 and the third CIS 36 in the transport direction.

The jig 50 is provided so that its side end 50a can be detected by each CIS. For example, the surface on the side to be detected is colored white so that it can be detected by each CIS.

The jig 50 has a rectangular shape, and the straightness of the side end 50a detected by each CIS is defined with high accuracy by the method described later.

A specific method for calculating the adjustment value using the jig 50 will be described with reference to the flow charts of FIGS. 11 and 12. In FIG. 11, it is assumed that the first CIS 34 and the third CIS 36 have no error in the mounting position in the width direction, and the second CIS 35 has an error in the mounting position in the width direction by a distance d in the lower direction of the figure.

In the adjustment mode, first, the jig 50 is arranged at the adjustment position (step Sa1 in FIG. 12).

Then, as shown in FIG. 11, the positions 50a1, 50a2, and 50a3 of the side ends 50a of the jig 50 at the respective positions are detected by the first CIS34, the second CIS35, and the third CIS36 (step Sa2). Using this detection result, the distances from the predetermined reference positions to the respective positions 50a1, 50a2, and 50a3 are calculated. For example, the distances L1, L2', and L3 from the reference line L0 to the positions 50a1, 50a2, and 50a3 are calculated. In this case, the first CIS34 and the third CIS36, which have no error in the mounting position, can detect the actual distances L1 and L3 from the reference line L0 to the positions 50a1 and 50a3 without error. On the other hand, the second CIS35 detects the distance L2'which is larger than the actual distance L2 by the distance d.

Assuming that the separation distance between the first CIS34 and the third CIS36 in the transport direction is the distance A, the skew amount θ2a of the jig 50 calculated from the detection result between the first CIS34 and the third CIS36 is
TANθ2a = (L3-L1) / A ... (2)
It can be expressed as. Further, assuming that the separation distance between the second CIS35 and the third CIS36 in the transport direction is the distance B, the skew amount θ2b of the jig 50 calculated from the detection results of the second CIS35 and the third CIS36 is
TANθ2b = (L3-L2') / B ... (3)
It can be expressed as.

If there is no error in the mounting position in each CIS, the values of θ2a and θ2b obtained by the equations (2) and (3) are equal. However, in reality, since the second CIS35 has a mounting error of the distance d, the distance X2'calculated by the detection result of the second CIS35 is larger by the distance d than the actual distance X2, so that the error occurs. Occurs. That is, by subtracting the error distance d from the distance L2'of the equation (3), the equation (2) and the equation (3) can be connected by an equation.
(L3-L1) / A = {L3- (L2'-d)} / B ... (4)
Is true. Therefore, the error distance d is
d =-(B / A) L1 + L2'-{(AB) / A] L3 ... (5)
It can be expressed as. That is, since the distances A and B are the values measured in advance and the distances L1, L2'and L3 are the values calculated from the detection results of each CIS, the error distance d can be obtained by the equation (5). can.

The error distance d thus obtained is the adjustment value d of the present embodiment used for adjusting the detection result of the second CIS35. As described above, in the present embodiment, the mounting error of the second CIS35 with respect to the first CIS34 and the third CIS36 is calculated as the adjustment value d. In other words, the present embodiment is an adjustment method for adjusting the detection results of the second CIS 35 with reference to the detection results of the first CIS 34 and the third CIS 36. However, the adjustment value is not limited to this, and the mounting error for any one of the CIS may be used as the adjustment value. Further, although FIG. 11 shows a case where the first CIS 34 and the third CIS 36 have no mounting error, there may be a case where these CIS have a mounting error.

The adjustment value d is calculated as described above (step Sa3). Then, the calculated adjustment value d is stored in the non-volatile memory (step Sa4). This completes the adjustment mode.

With this adjustment value d, the detection information of the paper P detected by the second CIS35 is adjusted. Specifically, the detection result of the second CIS 35 is adjusted during the first detection operation shown in step S3 of FIG. 9 and the second detection operation shown in step S7.

First, an adjustment method using the adjustment value d in the first detection operation and a method of calculating the position deviation amount of the paper P using the adjusted value will be described with reference to FIGS. 13 and 14. ..

As shown in FIG. 14, the first CIS34 and the second CIS35 detect the side edge positions Pa1 and Pa2 of the paper P, respectively (step Sb1 in FIG. 13). Then, the distances X1 and X2 between the positions Pa1 and Pa2 and the position X0 in the ideal width direction of the paper P are calculated. For the first CIS34 having no mounting error, the distance X1 can be calculated from the detection result. As for the second CIS35, since there is a mounting error of the distance d, the calculated distance X2'is a value larger than the actual distance X2 by the distance d. Therefore, the value (X2'-d) obtained by subtracting the adjustment value d from the distance X2'calculated by the detection result of the second CIS35 is defined as the amount of positional deviation in the width direction at the position Pa2, and this value and the first CIS34 The amount of positional deviation in the width direction is calculated based on the distance X1 calculated based on the detection result. Further, since the separation distance between the first CIS34 and the second CIS35 is the distance (AB), the skew amount θ3 of the paper P is determined.
TANθ3 = {(X2'-d) -X1} / (AB) ... (6)
Can be obtained by. In this way, the amount of misalignment of the paper P is calculated using the result of subtracting the adjustment value d from the distance X2'calculated by the detection result of the second CIS35 (steps Sb2 and Sb3).

As shown in FIG. 15, for the detection operation for re-correction by the same method, by subtracting the adjustment value d from the detection result of the second CIS35, the position shift and the skew amount in the width direction of the paper P are obtained. Can be calculated (steps Sc1 to Sc3).

As described above, in the present embodiment, the detection result of the second CIS 35 is corrected by using the adjustment value d. As a result, even if there is a mounting error between the second CIS35 and the first CIS34 and the third CIS36 and a paper position detection error occurs, the detection error can be corrected. That is, the correction target positions at the time of the first correction and the time of the re-correction can be brought closer to each other, and the correction operation is stable. As a result, it is possible to reduce the amount of correction especially during the re-correction operation, so that it is possible to prevent the re-correction operation from being unable to be completed by the time the paper P reaches the secondary transfer position, and the paper for the re-correction operation. The transport distance can also be made smaller. That is, the distance between the holding roller 32 and the secondary transfer roller 18 in the transport direction can be made smaller, and the device can be miniaturized.

By the way, the adjustment value d calculated above is the second CIS35, the first CIS34 and the third CIS36 when the side end 50a of the jig 50 forms a linear shape without a shape error (when the straightness is 0). It is the value of the mounting error for. However, in reality, the straightness does not become 0, such as a slight unevenness on the side end 50a. Then, as the value of this straightness becomes larger, the value of the adjustment value d deviates from the actual value of the mounting error of the second CIS35.

Therefore, in the present embodiment, the permissible value E, which is a permissible error value, is set, and the straightness s of the side end 50a, which can be an error equal to or less than the permissible value E, is calculated. Hereinafter, a method for calculating the straightness s will be described.

As shown in FIG. 11, the positions 50a1, 50a2, and 50a3 of the side ends 50a of the jig 50 are detected by the first CIS34, the second CIS35, and the third CIS36, and the respective distances L1, L2', and L3 are calculated. Can be done. Then, using the distance L1 calculated from the detection result of the first CIS34 and the value obtained by subtracting the adjustment value d from L2'calculated from the detection result of the second CIS35, the skew amount θ2c of the jig 50 is determined.
TANθ2c = {(L2'-d) -L1} / (AB) ... (7)
It can be expressed as. Then, using the value obtained by subtracting the adjustment value d from the distance L2'and the distance L3 calculated from the detection result of the third CIS 36, the skew amount θ2d of the jig 50 is determined.
TANθ2d = {L3- (L2'-d)} / B ... (8)
It can be expressed as.

Then, using these equations (7) and (8), the permissible value E of the detection error is determined.
E = {L3- (L2'-d)} / B- {(L2'-d) -L1} / (AB) ... (9)
Can be defined as. That is, the permissible value E is the skew amount calculated by the detection results of the second CIS35 and the third CIS36 when the adjustment value d is used (the skew amount calculated at the time of the second detection) and the first. The difference between the skew amount calculated from the detection result of CIS34 and the second CIS35 (the skew amount calculated at the time of the first detection), in other words, the detection amount at the time of the second detection and the detection at the time of the first detection. It can be obtained as the difference from the quantity.

Here, the shape error of the side end 50a of the jig 50 will be described with reference to FIG.
The side end 50a of the jig 50 is detected by each CIS at its three points 50a1, 50a2, and 50a3. Then, as shown in FIG. 16, it is assumed that the position 50a2 detected by the second CIS35 is deviated from the positions 50a1 and 50a3 by a distance s in the width direction. In this case, an error will occur in the value of the adjustment value d by the amount of this distance s. In other words, the value (ds) obtained by subtracting the distance s from the adjustment value d becomes the true adjustment value d0 without error. Therefore, when the adjustment value d0 and the equations (7) and (8) are used,
{(L2'-d0) -L1} / (AB) = {L3- (L2-d0)} / B ... (10)
It can be expressed as. Since the adjustment value d0 is (ds), it is obtained from the equations (9) and (10).
E = s / (AB) + s / B ... (11)
And the distance s is
s = {B (AB) / A} × E ... (12)
It can be expressed as. In FIG. 16, the inclination of the side end 50a is exaggerated and greatly expressed.

Assuming that the allowable error value E is in the range of −0.02 to 0.02 and A = 400 mm and B = 100 mm, these are substituted into the equation (12), and the distance d is −0.15 ≦. It can be obtained as s ≦ 0.15. In this way, by setting the allowable value E as the difference between the skew amount calculated at the time of the first detection and the skew amount calculated at the second detection, the value of the required distance s can be obtained. As described above, the distance s is the amount of vertical positional deviation of the position 50a2 detected by the second CIS35 at the side end 50a with respect to the positions 50a1 and 50a3 detected by the first CIS34 and the third CIS36. ..

In the present embodiment, the straightness of the side end 50a is defined in order to keep the distance s within the range of −0.15 ≦ s ≦ 0.15. For example, by defining the straightness of the side end 50a in the range of ± 0.075, the distance s can be kept in the range of −0.15 to 0.15. However, the method for setting the distance s within a predetermined range is not limited to this. That is, it is sufficient that the positional relationship between the positions 50a1, 50a2, and 50a3 detected by each CIS is accurately determined, and it is not always necessary to specify the straightness of the entire side end 50a as in the present embodiment. For example, the straightness in the range of the distance A may be specified, but in this case, in consideration of the error of the mounting position of the jig 50 with respect to the transport device 30 and the error of the mounting position of each CIS in the transport direction, each is actually used. It is necessary to set the specified straightness range in consideration of the variation of the positions 50a1, 50a2, and 50a3 detected by the CIS.

Further, by providing the jig 50 and the transfer device 30 with engaging portions, the jig 50 and the jig mounting portion of the transfer device 30 are engaged with each other, and the adjustment position of the jig 50 in the adjustment mode is accurately positioned. It may be a configuration. Thereby, each position of the side end 50a detected by each CIS can be accurately determined. Further, the transport device 30 may be provided with a reference line, a reference position, or the like for arranging the jig 50 at the adjustment position.

FIG. 17 is a block diagram showing a configuration of a control unit that controls each operation of the above transport device 30.
As shown in FIG. 17, the control unit 60 includes a first motor control unit 61, a second motor control unit 62, a position recognition unit 63, and an adjustment value calculation unit 64.

The first motor control unit 61 and the second motor control unit 62 are parts that control each movement operation of the sandwiching roller 32 based on the correction amount information sent from the position recognition unit 63.

The first motor control unit 61 is a part that controls the rotational operation of the holding roller 32 in the transport surface. In response to the signal from the first motor control unit 61, the first motor driver 611 drives the first motor 612 to rotate the holding roller 32 in the transport surface. Then, the rotation amount of the sandwiching roller 32 in the transport surface is detected by the first motor encoder 613.

The second motor control unit 62 is a portion that controls the movement operation of the sandwiching roller 32 in the width direction. In response to the signal from the second motor control unit 62, the second motor driver 621 drives the second motor 622 to move the sandwiching roller 32 in the width direction. Then, the second motor encoder 623 detects the amount of movement of the sandwiching roller 32 in the width direction.

These first motor 612 and second motor 622 pick up the holding roller 32 (step S4 in FIG. 9), return operation (step S6), re-correction operation (step S8), and return to the reference position. Will be driven at the time.

The position recognition unit 63 calculates the skew amount of the paper P and the position deviation amount in the width direction from the detection information received from each CIS. Then, the position recognition unit 63 determines the movement amount of the sandwiching roller 32 from this position deviation amount, and inputs it to the first motor control unit 61 and the second motor control unit 62.

The first motor control unit 61 and the second motor control unit 62 drive each motor according to the correction amount (movement amount) input from the position recognition unit 63, and rotate and rotate the holding roller 32 in the transport surface in the width direction. Move it.

As described above, the control unit 60 can move the sandwiching roller 32 based on the detection information of each CIS to correct the misalignment of the paper P.

Further, in the adjustment mode, the detection information that each CIS has detected the jig is input to the position recognition unit 63. The position recognition unit 63 calculates the skew amount of the jig from the input detection information. Then, the calculated skew amount is input to the adjustment value calculation unit 64, and the adjustment value calculation unit 64 calculates the adjustment value. The calculated adjustment value is stored in the non-volatile memory 65.

At the time of paper transfer, the adjustment value stored in the non-volatile memory 65 is input to the position recognition unit 63, and the detection result of the second CIS 35 is adjusted. Each operation of the transport device 30 is controlled by the above control unit 60.

The adjustment mode described above is usually performed before the image forming apparatus is shipped as a product, and the adjustment value is recorded in the non-volatile memory 65 in advance. Then, after the product is shipped, the detection result of the second CIS35 is adjusted by the adjustment value, the amount of misalignment is calculated, and the position of the paper P is corrected.

The adjustment mode can be performed before the product is shipped or at any time after the product is shipped. For example, when the CIS is removed once, such as by replacing or inspecting each CIS, the mounting error of the CIS changes. Therefore, by executing the adjustment mode at this timing, the adjustment value can be updated according to the change in the mounting error of each CIS. Further, a notification mechanism for urging the implementation of the adjustment mode may be provided, and notification for urging the implementation of the adjustment mode may be performed when each CIS is attached / detached. As a means for urging the implementation of the adjustment mode, a message urging the implementation of the adjustment mode can be displayed on the monitor provided in the image forming apparatus, or a warning sound can be emitted. The mechanism can be a notification mechanism.

Further, the adjustment mode may be executed when it is determined that the adjustment value is not properly set. Specifically, as shown in FIG. 9, when the position deviation amount calculated by the second detection operation in step S7 exceeds a predetermined value even though the first correction operation is performed up to step S6. It can be presumed that the cause is that the detection error between the first detection and the second detection is large. Therefore, when the amount of positional deviation calculated by the second detection operation exceeds a predetermined reference value by a certain number of times or more during a predetermined number of conveyed sheets (printed sheets), the configuration is such that the execution of the adjustment mode is promoted. Can be done.

When the adjustment mode is implemented, the jig 50 can be installed in the transport device 30 by opening the upper cover and opening the inside of the transport device 30. As a specific opening / closing configuration of the transport device 30, as shown in FIG. 18A, an upper cover 41 and a lower cover 42 are provided.

A transport path 6 is provided between the upper cover 41 and the lower cover 42. The lower surface of the upper cover 41 and the upper surface of the lower cover 42 function as an upper guide and a lower guide for guiding the paper P conveyed in the transport path 6 in a predetermined direction.

The upper cover 41 holds the first CIS34, the second CIS35, and the third CIS36, and fixes each CIS in a predetermined position with respect to the transport path 6. Further, the upper cover 41 is provided so as to be rotatable around the fulcrum 41a.

As shown in FIG. 18B, the inside of the transport device 30 is opened to the outside by rotating the upper cover 41 counterclockwise around the fulcrum 41a. In this state, the operator can place the jig 50 at a predetermined position on the lower cover 42 from the outside, and can arrange the jig 50 at the adjustment position. As described above, the lower cover 42 may be provided with an engaging portion such as a reference line or a rib for arranging the jig 50 at the adjustment position.

With the jig 50 placed at the adjustment position, the upper cover 41 is closed again, and the jig 50 is detected by each CIS. The adjustment value can be calculated using this detection result.

After the adjustment mode is executed, the upper cover 41 is opened to remove the jig 50, and then the upper cover 41 is closed again. By opening and closing the upper cover 41 in this way, the inside of the transport device 30 can be opened and closed. By the same method, the jam paper can be removed from the transport device 30, the CIS can be replaced, and the like.

Further, in the embodiment described above, the present invention has been applied to the transport device 30 installed in the electrophotographic image forming apparatus 1, but to the transport device installed in the inkjet type image forming apparatus. The present invention can also be applied. Further, the transport device of the present invention can also be applied to a post-processing device for post-processing an image-formed sheet (paper). Hereinafter, the inkjet type image forming apparatus will be described with reference to FIG. 19, and the post-processing apparatus will be described with reference to FIG. 20.

As shown in FIG. 19, the inkjet type image forming apparatus 100 includes a feeding unit 110, a conveying device 120, an image forming unit 130, a drying unit 140, and a paper ejection unit 150.

The paper P fed from the paper feed unit 110 is conveyed by the transfer device 120, and the image forming unit 130 is in a state where the positional deviation and skew in the width direction of the paper P are corrected as in the above-described embodiment. Is sent to.

In the image forming unit 130, the paper P is positioned on the cylindrical drum 131 and is conveyed in the direction of the arrow in the figure by the rotation of the cylindrical drum 131. Then, the paper P is conveyed to the lower part of the ejection head 132 of each color (the position where the image is formed on the paper P) at a predetermined timing, the ink of each color is discharged to the paper P, and the image is formed on the surface of the paper P. ..

The paper P on which the image is formed by the image forming unit 130 is conveyed to the drying unit 140 to evaporate the moisture in the ink, and then is discharged to a position where the operator can take it out by the paper ejection unit 150.

When double-sided printing is performed, after the drying step, the paper P is sent to the reverse transfer path 160, and the paper P is sent to the transfer device 120 again with the front and back sides inverted.

(Post-processing device)
FIG. 20 shows an embodiment in which the present invention is applied to an aftertreatment device. The post-processing device 200 shown in FIG. 20 includes a punching device 210 for punching the paper P, a staple processing device 220 for binding the paper P, and a folding processing device 230 for performing a center-folding process on the paper P. The trays (loading portions) 241,242, 243 are provided. The post-processing apparatus 200 conveys the paper P conveyed from the image forming apparatus 1 to one of the three transfer paths Q1 to Q3, and performs different post-processing.

The first transport path Q1 is a path for transporting the paper P punched by the punching device 210 or the paper P not punched to the first tray 241. The second transport path Q2 is a path for transporting the paper P to the staple processing device 220 and transporting the bound paper P to the second tray 242. The third transport path Q3 is a path for transporting the paper P to the folding processing apparatus 230 and transporting the middle-folded paper P to the third tray 243.

Here, as shown in FIG. 20, the paper P conveyed from the image forming apparatus 1 to the post-processing apparatus 200 is first of the same as described above by the holding roller 32 provided on the upstream side of the punching apparatus 210. Oblique correction and position shift correction in the width direction are performed. This makes it possible to improve the accuracy of the subsequent punching process, binding process, or center folding process.

In the above embodiments, the case where the sheet detection device and the transfer device detect and convey the sheet (paper) on which the image is formed in the configuration provided in the image forming device has been shown. The device or the transport device provided with the sheet detection device may be provided independently. In this case, the sheet detection device or the transfer device is provided with a control unit for calculating adjustment values and the like.

Sheets include paper P (plain paper), thick paper, postcards, envelopes, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, transparencies, plastic films, prepregs, copper foil, etc. Is done.

1 Image forming device 18 Secondary transfer roller 30 Conveying device 31 Conveying roller 32 Holding roller (conveying member)
34 First CIS (First Detection Mechanism)
35 Second CIS (Second Detection Mechanism)
36 Third CIS (Third Detection Mechanism)
50 Jig 50a Side end 60 Control unit 70 Sheet detection device d Adjustment value θ Oblique amount P Paper (sheet)

Japanese Unexamined Patent Publication No. 2016-175776

Claims (9)

A first detection mechanism, a second detection mechanism, and a third detection mechanism , which have a plurality of sensors arranged side by side in the width direction of the seat and can detect the position of the seat by the plurality of sensors.
The amount of skew of the sheet or the jig is calculated by using the detection result of the sheet or the jig by any two of the first detection mechanism, the second detection mechanism, and the third detection mechanism. It is a seat detection device equipped with a control unit that can be used .
The first detection mechanism, the second detection mechanism, and the third detection mechanism are arranged side by side in a direction orthogonal to the width direction of the sheet and in a direction different from the thickness direction of the sheet.
The jig is arranged so as to face the first detection mechanism, the second detection mechanism, and the third detection mechanism.
The first detection mechanism and the second detection mechanism perform the first detection to detect the position of the sheet or the jig.
The second detection mechanism and the third detection mechanism perform second detection to detect the position of the sheet or the jig.
The first detection mechanism, the second detection mechanism, and the third detection are based on the skew amount of the jig calculated by the control unit using the detection results of the first detection and the second detection. A sheet detection device characterized in that the detection position of the sheet detected by at least one of the mechanisms is adjusted . In the jig, the straightness of the side end detected by the first detection mechanism, the second detection mechanism, and the third detection mechanism is defined as a predetermined value or less.
The sheet detection device according to claim 1 , wherein the predetermined value of straightness is determined based on an allowable value of a detection error that occurs between the first detection and the second detection. A transport device including the sheet detection device according to claim 1 or 2 , and a transport member for transporting the sheet. The transport member transports the sheet and corrects the positional deviation of the sheet.
The third aspect of claim 3 , wherein the control unit causes the transport member to perform a first correction operation based on the detection result of the first detection, and to perform a re-correction operation based on the detection result of the second detection. Conveyor device. An image forming apparatus comprising the transport device according to claim 3 or 4 . It also has a notification mechanism to notify the status of the device to the outside.
The transport member transports the sheet and corrects the positional deviation of the sheet.
The control unit causes the transport member to perform a first correction operation based on the detection result of the first detection, and a re-correction operation based on the detection result of the second detection.
When the amount of positional deviation of the sheet calculated by the control unit exceeds a predetermined reference value based on the detection result detected by the second detection , the notification mechanism prompts adjustment using the jig. The image forming apparatus according to claim 5 , wherein the notification is performed. It also has a notification mechanism to notify the status of the device to the outside.
5. Claim 5 that when at least one of the first detection mechanism, the second detection mechanism, and the third detection mechanism is attached / detached, the notification mechanism notifies the adjustment using the jig. Or 6 The image forming apparatus according to any one of 6. Adjustment of the seat detection position of the first detection mechanism, the second detection mechanism, and the third detection mechanism, which have a plurality of sensors arranged side by side in the width direction of the seat and can detect the position of the seat by the plurality of sensors. It ’s a method,
The first detection mechanism, the second detection mechanism, and the third detection mechanism are arranged side by side in a direction orthogonal to the width direction of the sheet and in a direction different from the thickness direction of the sheet.
A jig is placed facing the first detection mechanism, the second detection mechanism, and the third detection mechanism.
The first detection mechanism and the second detection mechanism perform the first detection to detect the position of the jig.
The second detection mechanism and the third detection mechanism perform second detection to detect the position of the jig.
At least one of the first detection mechanism, the second detection mechanism, and the third detection mechanism, depending on the amount of skew of the jig calculated by using the detection results of the first detection and the second detection. A method for adjusting a sheet detection position, which comprises adjusting the detection position of the sheet detected by one . The first detection mechanism, the second detection mechanism, and the third detection mechanism are provided in the seat detection device.
When at least one of the first detection mechanism, the second detection mechanism, and the third detection mechanism is attached to and detached from the sheet detection device, the first detection mechanism, the second detection mechanism, and The method for adjusting a sheet detection position according to claim 8 , wherein the detection result of at least one of the third detection mechanisms is adjusted again.

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