JP5444907B2 - Medium conveying apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a medium conveying apparatus and an image forming apparatus.

  In the image forming apparatus, in order to prevent an image from being recorded on the medium at an inclination, a technique for correcting a skewed state of the conveyed medium, that is, a so-called skew is used. As such a skew correction technique, techniques described in the following Patent Documents 1 to 3 are known.

Japanese Patent Application Laid-Open No. 2002-60097 as Patent Document 1 is provided at one width end of the second sheet conveying path (R2) for conveying the sheet and the second sheet conveying path (R2). A side guide (32), a skew roller (37) for conveying the sheet conveyed through the second sheet conveyance path (R2) to the side guide (32) side and the sheet conveyance direction (Y) downstream side; There is described a color image forming apparatus (1) having a registration roller (27) provided on the downstream side of the side guide (32) and the skew roller (37).
In the technique described in Patent Document 1, the skew roller (37) is installed on a base (36) that is rotatably supported by a rotation support shaft (36), and according to the state and type of the sheet. The tilting roller (37) is rotated together with the base (36) to change the tilt angle of the skewing roller (37) with respect to the side guide (32).
That is, the side reference surface of the side guide (32) is changed by changing the inclination angle of the skew roller (37) according to the ease of conveyance by the skew roller (37) based on the state and type of the sheet. Insufficient correction of buckling and skew when the sheet contacts (33). Then, the sheet whose skew is corrected by the side guide (32) is conveyed to the registration roller (27).

Japanese Patent Application Laid-Open No. 2002-284399 as Patent Document 2 describes a copying machine having a sheet skew correcting and conveying device (5). The sheet skew correcting and conveying device (5) includes a left skew correcting roller pair that is rotated by a left skew correcting motor (M5) in a direction from upstream to downstream of the transfer direction of the transfer material (P). (142a) and a right skew correction roller pair (142b) rotated by the right skew correction motor (M6) and paired with the left skew correction roller pair (142a).
In Patent Document 2, in the sheet skew correction conveyance device (5), a difference is provided in the rotational speed of the skew correction roller pair (142a, 142b), and the transfer material (P) is transferred while being conveyed downstream. Correction by an active registration method in which the skew is corrected by rotating the material (P), or the transfer material (P) is brought into contact with the stopped skew correction roller pair (142a, 142b) by contacting the leading end of the transfer material (P). Describes a technique for performing correction by a loop registration method in which a curve, that is, a so-called loop is formed to correct a skew of the transfer material (P).
In the technique described in Patent Document 2, skew correction is performed by the loop registration method for paper that is likely to cause idle rotation, such as thick paper that is stiff, and the active registration method is used to increase the number of printed sheets. The skew correction method of the transfer material (P) is changed according to the type and setting of the medium, such as performing skew correction.

In Japanese Patent Application Laid-Open No. 2005-15195 as Patent Document 3, it is possible to move in the width direction, which is a direction perpendicular to the conveyance direction of the paper (1), and the driving means (2) composed of a solenoid and a spring (6). And a shaft that is moved in the width direction by the driving means (2), and is supported by the shaft, and when the shaft moves in the width direction, the angle changes with respect to the transport direction, and the sheet (1 ) Inclined to move in the width direction, a conveyance roller (3), a portion on which the sheet (1) disposed downstream of the conveyance roller (3) is stacked, and the portion to be stacked Is a sheet aligning device having a sheet reference aligning plate (4a) and a sheet aligning aligning plate (4b) arranged on both sides of the sheet.
In the technique described in Patent Document 3, the angle of the transport roller (3) is changed, and the sheet (1) is placed in a slanted state with the downstream end facing the sheet alignment plate (4b). ) Move to the side and carry. Based on the information from the detection means (5), the angle of the transport roller (3) is switched before the downstream end of the paper (1) collides with the paper alignment plate (4b), and the paper alignment plate ( The position in the width direction of the sheet (1) is changed so as not to collide with 4b).

JP 2002-60097 ("0030" to "0037", "0061" to "0074", FIG. 2, FIG. 3, FIG. 8) JP 2002-284399 A ("0012" to "0015", "0069" to "0078", FIG. 5) Japanese Patent Laying-Open No. 2005-15195 (“0008”, FIGS. 1 and 2)

  It is a technical object of the present invention to accurately correct the tilt of a medium.

In order to solve the technical problem, a medium conveying device according to claim 1 is provided.
A transport path through which the medium is transported;
A downstream end aligning member that is provided in the transport path and aligns the posture of the medium when the downstream end of the medium transported in the transport path on the downstream side of the medium is abutted;
Provided in the transport path, configured to be able to contact a side end in a medium width direction that is a direction orthogonal to a medium transport direction of a medium transported through the transport path, and the side end of the medium is in contact A side end aligning member that aligns the posture of the medium,
A feed member that is arranged on the upstream side of the downstream end alignment member and that sends the medium transported through the transport path to the downstream side;
A feed discriminating means for discriminating whether or not the medium satisfies a feed condition for sending the medium transported in the transport path to the side edge aligning member side;
When it is determined by the feeding determining means that the medium satisfies the feeding condition, the feeding member is controlled to send the medium to the side edge aligning member side, and the side edge of the medium is When the medium is brought into contact with the side edge aligning member and the medium is determined that the medium does not satisfy the condition for feeding, the medium is fed to the downstream edge aligning member side by controlling the feeding member. Feed member control means for abutting the downstream end of the medium against the downstream end alignment member;
A first feed position for feeding the medium to the downstream end aligning member side, and a second feed position for sending the medium in a direction inclined toward the side end aligning member with respect to the direction of feeding the medium to the downstream end aligning member side And the feeding member provided to be movable between,
When it is determined by the feed determining means that the medium satisfies the feed condition, the feed member is moved to the second feed position, and the medium satisfies the feed condition by the feed determining means. The feed member control means for moving the feed member to the first feed position when it is determined that there is not,
It is provided with.

In order to solve the technical problem, a medium conveying device according to claim 2 is provided.
A transport path through which the medium is transported;
A downstream end aligning member that is provided in the transport path and aligns the posture of the medium when the downstream end of the medium transported in the transport path on the downstream side of the medium is abutted;
Provided in the transport path, configured to be able to contact a side end in a medium width direction that is a direction orthogonal to a medium transport direction of a medium transported through the transport path, and the side end of the medium is in contact A side end aligning member that aligns the posture of the medium,
A feed member that is arranged on the upstream side of the downstream end alignment member and that sends the medium transported through the transport path to the downstream side;
A feed discriminating means for discriminating whether or not the medium satisfies a feed condition for sending the medium transported in the transport path to the side edge aligning member side;
When it is determined by the feeding determining means that the medium satisfies the feeding condition, the feeding member is controlled to send the medium to the side edge aligning member side, and the side edge of the medium is When the medium is brought into contact with the side edge aligning member and the medium is determined that the medium does not satisfy the condition for feeding, the medium is fed to the downstream edge aligning member side by controlling the feeding member. Feed member control means for abutting the downstream end of the medium against the downstream end alignment member;
The oblique feeding member that feeds the medium in a direction inclined toward the side edge aligning member with respect to the direction of feeding the medium toward the downstream end aligning member, and the oblique feeding member that is supported so as to be movable in the medium width direction. And a support member that supports the feed member,
When it is determined by the feed determining means that the medium satisfies the feed condition, the support member is stopped and the medium is sent to the oblique feed member, and the medium is detected by the feed determining means. When it is determined that the feeding condition is not satisfied, the medium is sent to the oblique feeding member while moving the support member in a direction away from the side edge aligning member, whereby the medium is sent to the downstream edge aligning member. The feeding member control means to abut,
It is provided with.

In order to solve the technical problem, an image forming apparatus according to claim 3 is provided.
The medium conveying device according to claim 1 or 2 ,
An image recording unit for recording an image on a medium conveyed by the medium conveying device;
It is provided with.

According to the first , second, and third aspects of the invention, the inclination of the medium can be corrected with higher accuracy than when the configuration of the present invention is not provided.
According to the first aspect of the present invention, the transport direction of the medium can be switched by moving the feed member between the first feed position and the second feed position.
According to the second aspect of the present invention, the conveyance direction of the medium can be switched by moving the diagonally-feeding member in the medium width direction or stationary.

FIG. 1 is an overall explanatory view of an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is an explanatory view of a visible image forming member having an image carrier unit and a developing device. FIG. 3 is an explanatory diagram of the sheet conveyance path and an explanatory diagram of the skew correction area. FIG. 4 is an explanatory diagram of a mechanism for moving the registration roll in the medium width direction. FIG. 5 is an explanatory diagram of the cross-trolling of the first embodiment, FIG. 5A is an explanatory diagram viewed in the direction of the VA-VA line in FIG. 3, FIG. 5B is an explanatory diagram of gears and racks, and FIG. FIG. 5D is an explanatory diagram of a state where the driving cross-trolle has moved to the guide feeding position. FIG. 6 is an explanatory view of the cross trol and the nip pressure adjusting member, FIG. 6A is an explanatory view of the cross trol at the contact position, and FIG. 6B is an explanatory view of the cross trol at the separated position. FIG. 7 is a block diagram illustrating the functions of the control unit of the image forming apparatus according to the first embodiment. FIG. 8 is a block diagram illustrating functions provided in the control unit of the image forming apparatus according to the first exemplary embodiment, and is a continuation of FIG. FIG. 9 is a flowchart of skew correction processing as an example of medium tilt correction processing according to the first embodiment of the present invention. FIG. 10 is a flowchart of the side edge alignment process according to the first embodiment of the present invention. FIG. 11 is a flowchart of downstream end alignment processing according to the first embodiment of the present invention. FIG. 12 is an explanatory diagram when the cross trolling is moved to the side feeding position, FIG. 12A is an explanatory diagram before the recording sheet S is conveyed, and FIG. 12B is an explanatory diagram subsequent to FIG. FIG. 12C is an explanatory diagram subsequent to FIG. 12B, an explanatory diagram when the recording sheet is in contact with the side guide, and FIG. 12D is an explanatory diagram subsequent to FIG. 12E is an explanatory diagram when the downstream end of the sheet is detected by the downstream registration sensor, FIG. 12E is an explanatory diagram subsequent to FIG. 12D, and an explanatory diagram when the side end of the recording sheet is detected by the side sensor. FIG. 13 is an explanatory diagram when the cross-trol is moved to the registration feeding position, FIG. 13A is an explanatory diagram before the recording sheet S is conveyed, and FIG. 13B is an explanatory diagram subsequent to FIG. FIG. 13C is an explanatory diagram subsequent to FIG. 13B and is an explanatory diagram when the recording sheet is in contact with the registration roll. FIG. 13D is an explanatory diagram subsequent to FIG. 13C and an explanatory diagram when the recording sheet is sent to the registration roll. 13E is an explanatory diagram when the downstream registration sensor is detected by the downstream registration sensor, and FIG. 13E is an explanatory diagram subsequent to FIG. 13D and an explanatory diagram when the side edge of the recording sheet is detected by the side sensor. FIG. 14 is an explanatory diagram of the sheet conveyance path of the second embodiment and corresponds to FIG. 3 of the first embodiment. FIG. 15 is an explanatory diagram of the cross-trolling of Example 2, FIG. 15A is a diagram corresponding to FIG. 5A of Example 1, FIG. 15B is an explanatory diagram of a state where the pre-registration roll has moved to the contact position, and FIG. It is explanatory drawing of the state which separated. FIG. 16 is a block diagram illustrating the functions of the control unit of the image forming apparatus according to the second embodiment, and corresponds to FIG. 7 according to the first embodiment. FIG. 17 is a block diagram illustrating functions provided in the control portion of the image forming apparatus according to the second embodiment, and is an explanatory diagram subsequent to FIG. FIG. 18 is a flowchart of the side edge alignment process according to the second embodiment of the present invention, and corresponds to FIG. 10 according to the first embodiment. FIG. 19 is a flowchart of downstream end alignment processing according to the second embodiment of the present invention, and corresponds to FIG. 11 according to the first embodiment. FIG. 20 is an explanatory diagram when the recording sheet is conveyed by the feeding member. FIG. 20A is an explanatory diagram when the recording sheet is conveyed by the cross roll, and is an explanatory diagram before the recording sheet is conveyed. FIG. 20C is an explanatory diagram when the recording sheet is conveyed, FIG. 20C is an explanatory diagram subsequent to FIG. 20B, an explanatory diagram when the skew of the recording sheet is corrected, and FIG. 20D is an explanatory diagram when the recording sheet is moved by the pre-registration roll. FIG. 20E is an explanatory diagram before the recording sheet is conveyed in the explanatory diagram when conveyed, FIG. 20E is an explanatory diagram subsequent to FIG. 20D, an explanatory diagram when the recording sheet is conveyed, and FIG. 20F is an explanatory diagram subsequent to FIG. FIG. 6 is an explanatory diagram when the skew of the recording sheet is corrected. FIG. 21 is an explanatory diagram of the sheet conveyance path of the third embodiment, and corresponds to FIG. 14 of the second embodiment. FIG. 22 is an explanatory diagram of the feeding member of the third embodiment and corresponds to FIG. 15A of the second embodiment. FIG. 23 is a block diagram illustrating the functions of the control unit of the image forming apparatus according to the third embodiment, and corresponds to FIG. 16 according to the second embodiment. FIG. 24 is a block diagram illustrating the functions of the control unit of the image forming apparatus according to the third embodiment, and is an explanatory diagram subsequent to FIG. FIG. 25 is an explanatory diagram of the cross-trolling conveyance speed and the crossing holder moving speed, FIG. 25A is an explanatory diagram of the recording sheet conveyance speed by the cross-trolling, and FIG. 25B is a recording sheet by the cross-trolling when the crossing holder moves. It is explanatory drawing of the conveyance speed of. FIG. 26 is a flowchart of the side edge alignment process according to the third embodiment of the present invention, and corresponds to FIG. 10 according to the first embodiment. FIG. 27 is a flowchart of downstream end alignment processing according to the third embodiment of the present invention, and corresponds to FIG. 11 according to the first embodiment. FIG. 28 is a flowchart of downstream end alignment processing according to the third embodiment of the present invention, and is an explanatory diagram continued from FIG. FIG. 29 is an explanatory diagram when the recording sheet is conveyed by the feeding member of the third embodiment, and FIG. 29A is an explanatory diagram when the cloth holder is stationary and conveys the recording sheet, and is an explanation before the recording sheet is conveyed. 29B is an explanatory diagram subsequent to FIG. 29A and is an explanatory diagram when the recording sheet is conveyed. FIG. 29C is an explanatory diagram subsequent to FIG. 29B and an explanatory diagram when the skew of the recording sheet is corrected. FIG. Fig. 29 is an explanatory diagram when the recording sheet is conveyed while the crosted holder is moved, and is an explanatory diagram when the recording sheet passes through the upstream clost sensor. Fig. 29E is an explanatory diagram continued from Fig. 29D when the recording sheet is conveyed. FIG. 29F is an explanatory diagram subsequent to FIG. 29E and is an explanatory diagram when the skew of the recording sheet is corrected.

Next, specific examples of embodiments of the present invention (hereinafter referred to as examples) will be described with reference to the drawings, but the present invention is not limited to the following examples.
In order to facilitate understanding of the following description, in the drawings, the front-rear direction is the X-axis direction, the left-right direction is the Y-axis direction, the up-down direction is the Z-axis direction, and arrows X, -X, Y, -Y, The direction indicated by Z and -Z or the indicated side is defined as the front side, the rear side, the right side, the left side, the upper side, the lower side, or the front side, the rear side, the right side, the left side, the upper side, and the lower side, respectively.
In the figure, “•” in “○” means an arrow heading from the back of the page to the front, and “×” in “○” is the front of the page. It means an arrow pointing from the back to the back.
In the following description using the drawings, illustrations other than members necessary for the description are omitted as appropriate for easy understanding.

FIG. 1 is an overall explanatory view of an image forming apparatus according to Embodiment 1 of the present invention.
In FIG. 1, an image forming apparatus U includes a user interface UI as an example of an operation unit, an image input apparatus U1 as an example of an image information input apparatus, a paper feeding apparatus U2, an image forming apparatus main body U3, and a paper processing apparatus U4. Have.

The user interface UI includes input buttons such as a copy start key UI1, a numeric keypad UI2, a copy number input key UI3, and a tray setting key UI4, which will be described later, a display panel UI0, and the like.
The image input device U1 includes an automatic document feeder U1a and an image scanner U1b as an example of an image reading unit. In FIG. 1, an image input apparatus U1 reads a document (not shown), converts it into image information, and inputs it to the image forming apparatus body U3.
The sheet feeding device U2 takes out the sheet feeding trays TR1 to TR4 as an example of a plurality of medium accommodating units and the recording sheet S as an example of a medium accommodated in each of the sheet feeding trays TR1 to TR4, and main body of the image forming apparatus. A sheet feeding path SH1 and the like for conveying to U3 are provided.

In FIG. 1, an image forming apparatus main body U3 includes an image recording unit U3a that records an image on a recording sheet S conveyed from the sheet feeding device U2, a toner dispenser device U3b as an example of a developer supply device, and a conveyance path. As an example, a sheet conveyance path SH2, a sheet discharge path SH3, a sheet reversing path SH4, a sheet circulation path SH6, and the like are provided. The image recording unit U3a will be described later.
The image forming apparatus body U3 is controlled by a controller C as an example of a control unit, a laser drive circuit D as an example of a latent image writing device drive circuit controlled by the controller C, and the controller C. A power supply circuit E and the like are included. The laser drive circuit D, the operation of which is controlled by the controller C, outputs a laser drive signal corresponding to image information of Y: yellow, M: magenta, C: cyan, K: black input from the image input device U1. At the timing, the image is output to the latent image forming apparatuses ROSy, ROSm, ROSc, and ROSk of each color.
Below the latent image forming apparatuses ROSy, ROSm, ROSc, and ROSk of the respective colors, an extraction position where the image forming unit drawing member U3c is drawn to the front of the image forming apparatus main body U3 by a pair of left and right guide members R1 and R1. And a mounting position mounted in the image forming apparatus main body U3.

FIG. 2 is an explanatory view of a visible image forming member having an image carrier unit and a developing device.
1 and 2, the K-color image carrier unit Uk includes an image carrier Pk, a charger CCk as an example of a discharger, and a cleaner CLk as an example of an image carrier cleaner. . The image holding units Uy, Um, and Uc of other colors Y, M, and C also have image holding members Py, Pm, and Pc, chargers CCy, CCm, and CCc, and cleaners CLy, CLm, and CLc. . In Example 1, the K-color image carrier Pk, which is frequently used and has a lot of surface wear, is configured to have a larger diameter than the other color image carriers Py, Pm, Pc, and is capable of high-speed rotation. Long life has been achieved.
Visible image forming members Uy + Gy, Um + Gm, Uc + Gc, Uk + Gk are constituted by the image carrier units Uy, Um, Uc, Uk and developing devices Gy, Gm, Gc, Gk having a developing roll R0. The image holding unit Uy, Um, Uc, Uk and developing units Gy, Gm, Gc, Gk are detachably mounted on the image forming unit drawing member U3c.

  In FIG. 1, image carriers Py, Pm, Pc, and Pk are uniformly charged by chargers CCy, CCm, CCc, and CCk, respectively, and then output from the latent image forming devices ROSy, ROSm, ROSc, and ROSk. An electrostatic latent image is formed on the surface of the laser beam Ly, Lm, Lc, Lk as an example of the latent image writing light. The electrostatic latent images on the surfaces of the image carriers Py, Pm, Pc, and Pk are converted into toner images of Y: yellow, M: magenta, C: cyan, and K: black by developing units Gy, Gm, Gc, and Gk. Developed.

The toner image on the surface of the image carrier Py, Pm, Pc, Pk is intermediately transferred in primary transfer regions Q3y, Q3m, Q3c, Q3k by primary transfer rolls T1y, T1m, T1c, T1k as an example of a primary transfer device. The images are sequentially transferred onto an intermediate transfer belt B as an example of the body, and a multicolor image, so-called color image, is formed on the intermediate transfer belt B. The color image formed on the intermediate transfer belt B is conveyed to a secondary transfer area Q4 as an example of an image recording area.
In the case of black image data only, only K: black image carrier Pk and developing unit Gk are used, and only a black toner image is formed.
After the primary transfer, the residual toner on the surface of the image carrier Py, Pm, Pc, Pk is cleaned by the image carrier cleaners CLy, CLm, CLc, CLk.

Below the image forming unit drawing member U3c, there is a space between the drawing position where the intermediate transfer member drawing member U3d is drawn to the front of the image forming apparatus body U3 and the mounting position where the image forming apparatus body U3 is mounted. It is supported so that it can move. The intermediate transfer member pull-out member U3d allows the belt module BM as an example of an intermediate transfer device to come into contact with the lower surface of the image carriers Py, Pm, Pc, and Pk, and to move downward from the lower surface. It is supported so that it can move up and down.
The belt module BM includes the intermediate transfer belt B, a belt support roll (Rd, Rt, Rw, Rf, T2a) as an example of an intermediate transfer member support member, and the primary transfer rolls T1y, T1m, T1c, T1k. And have. The belt support roll (Rd, Rt, Rw, Rf, T2a) includes a belt drive roll Rd as an example of an intermediate transfer member drive member, a tension roll Rt as an example of a tension applying member, and a walking roll as an example of a meandering prevention member. Rw, a plurality of idler rolls Rf as an example of a driven member, and a backup roll T2a as an example of a secondary transfer counter member. The intermediate transfer belt B is supported by the belt support rolls (Rd, Rt, Rw, Rf, T2a) so as to be rotatable in the arrow Ya direction.

A secondary transfer unit Ut is disposed below the backup roll T2a. A secondary transfer roll T2b as an example of a secondary transfer member of the secondary transfer unit Ut is disposed so as to be separated from and contactable with the backup roll T2a with the intermediate transfer belt B interposed therebetween. The secondary transfer roll T2b is A secondary transfer region Q4 as an example of an image recording region is formed by the region in pressure contact with the intermediate transfer belt B. Further, a contact roll T2c as an example of a voltage application contact member is in contact with the backup roll T2a, and a secondary transfer device T2 is constituted by the rolls T2a to T2c.
A secondary transfer voltage having the same polarity as the toner charging polarity is applied to the contact roll T2c from the power supply circuit controlled by the controller C at a predetermined timing.

A sheet conveyance path SH2 as an example of a conveyance path is disposed below the belt module BM. The recording sheet S fed from the sheet feeding device U2 is conveyed from the sheet feeding path SH1 to the sheet conveying path SH2 by a conveyance roll Ra as an example of a conveyance member. Then, the registration guide Rr as an example of the downstream end alignment member, which is an example of a conveyance timing adjusting member, matches the timing when the toner image is conveyed to the secondary transfer region Q4, so that the medium guide member SGr, the pre-transfer It is conveyed to the secondary transfer region Q4 through the medium guide member SG1.
The medium guide member SGr is fixed to the image forming apparatus main body U3 together with the registration roll Rr.
The toner image on the intermediate transfer belt B is transferred to the recording sheet S by the secondary transfer device T2 when passing through the secondary transfer region Q4. Note that in the case of a full-color image, the toner images primarily transferred onto the surface of the intermediate transfer belt B are secondarily transferred onto the recording sheet S at once.

The intermediate transfer belt B after the secondary transfer is cleaned, that is, cleaned by a belt cleaner CLB as an example of an intermediate transfer body cleaner. The secondary transfer roll T2b and the belt cleaner CLB are supported so as to be separated from and in contact with the intermediate transfer belt B.
A transfer device T1 + B + T2 + CLB that transfers the image on the surface of the image carrier Py to Pk onto the recording sheet S by the primary transfer rolls T1y, T1m, T1c, T1k, the intermediate transfer belt B, the secondary transfer device T2, the belt cleaner CLB, etc. It is configured.
The visible image forming member Uy + Gy to Uk + Gk and the transfer device T1 + B + T2 + CLB constitute an image recording unit U3a of Example 1.

The recording sheet S on which the toner image has been secondarily transferred is conveyed to the fixing device F through a post-transfer medium guide member SG2 and a sheet conveyance belt BH as an example of a medium conveyance member before fixing. The fixing device F has a heating roll Fh as an example of a heat fixing member and a pressure roll Fp as an example of a pressure fixing member, and is fixed by a region where the heating roll Fh and the pressure roll Fp are in pressure contact with each other. Region Q5 is formed.
The toner image on the recording sheet S is heated and fixed by the fixing device F when passing through the fixing region Q5. A transport path switching member GT1 is provided on the downstream side of the fixing device F. The conveyance path switching member GT1 selectively switches the recording sheet S conveyed in the sheet conveyance path SH2 and heated and fixed in the fixing region Q5 to either the sheet discharge path SH3 or the sheet reversal path SH4. The sheet S conveyed to the sheet discharge path SH3 is conveyed to the sheet conveyance path SH5 of the sheet processing apparatus U4.

  A curl correction device U4a is disposed in the middle of the sheet conveyance path SH5, and a switching gate G4 as an example of a conveyance path switching member is disposed in the sheet conveyance path SH5. The switching gate G4 causes the recording sheet S conveyed from the sheet conveying path SH3 of the image forming apparatus main body U3 to be curved, so-called curl direction, depending on the first curl correction member h1 or the second curl correction member h2. Transport to either side of The recording sheet S conveyed to the first curl correction member h1 or the second curl correction member h2 is curled when passing. The recording sheet S with the curl corrected is in a so-called face-up state in which the image fixing surface of the sheet is directed upward from a discharge roll Rh as an example of a discharge member to a discharge tray TH1 as an example of a discharge unit of the paper processing device U4. It is discharged at.

The recording sheet S conveyed to the sheet reversing path SH4 side of the image forming apparatus main body U3 by the conveyance path switching member GT1 pushes the conveyance direction regulating member constituted by an elastic thin film member, so-called mylar gate GT2. Passed and conveyed to the sheet reversing path SH4 of the image forming apparatus main body U3.
A sheet circulation path SH6 and a sheet reversing path SH7 of the sheet processing apparatus U4 are connected to the downstream end of the sheet reversing path SH4 of the image forming apparatus main body U3, and a Mylar gate GT3 is also disposed at the connecting portion. . The paper transported to the paper transport path SH4 through the switching gate GT1 passes through the mylar gate GT3 and is transported to the paper reversing path SH7. When performing duplex printing, the recording sheet S that has been transported through the paper reversing path SH4 passes through the Mylar gate GT3 as it is, is transported to the paper reversing path SH7, and then transported in the opposite direction. When switched back, the transport direction is regulated by the mylar gate GT3, and the recording sheet S switched back is transported to the paper circulation path SH6 side. The recording sheet S conveyed to the paper circulation path SH6 is retransmitted to the transfer area Q4 through the paper supply path SH1.
The sheet reversing path SH4, the sheet circulating path SH6, the sheet reversing path SH7, and the like constitute a sheet reversing path SH4 + SH6 + SH7 as an example of the reversing path of the first embodiment.

On the other hand, when the recording sheet S conveyed through the sheet reversing path SH4 is switched back after the trailing end of the recording sheet S passes through the Mylar gate GT2 and before passing through the Mylar gate GT3, the Mylar gate GT2 causes the recording sheet S to move. The conveyance direction is regulated, and the recording sheet S is conveyed to the sheet conveyance path SH5 with the front and back sides reversed. The recording sheet S whose front and back sides are reversed is subjected to curl correction by the curl correction device U4a, and then the image fixing surface of the paper S faces downward on the paper discharge tray TH1 of the paper processing device U4, so-called face-down state. Can be discharged.
A medium transport path SH is configured by the elements indicated by the symbols SH1 to SH7. Further, the elements indicated by the symbols TR1 to TR4, SH, Ra, Rr, Rh, SGr, SG1, SG2, BH, GT1 to GT3, C, and the like constitute a sheet conveying device SU as an example of a medium conveying device. Has been.

(Description of the skew correction area)
(Description of registration roll Rr)
FIG. 3 is an explanatory diagram of the sheet conveyance path and an explanatory diagram of the skew correction area.
FIG. 4 is an explanatory diagram of a mechanism for moving the registration roll in the medium width direction.
In FIG. 3, a registration roll Rr, which is an example of a conveyance timing adjusting member and an example of a downstream end aligning member, is disposed on the upstream side of the secondary transfer region Q4 in the sheet conveyance path SH2.
In FIG. 4, the registration roll Rr includes a driving registration roll Rr1 as an example of a driving side member and a driven registration roll Rr2 as an example of a driven side member facing the driving registration roll Rr1.
The drive registration roll Rr1 has a drive side support shaft 1 extending in the front-rear direction. The drive-side support shaft 1 is movable in the medium width direction, which is a direction orthogonal to the conveyance direction of the recording sheet S, and is rotatable on a pair of front and rear support portions U3e provided in the image forming apparatus main body U3. It is supported.

  A shift rack 2 as an example of a first transmitted member is supported at the rear end of the drive side support shaft 1. The shift rack 2 has crests and valleys formed in a direction perpendicular to the drive-side support shaft 1, and even if the drive-side support shaft 1 rotates, the teeth of the shift rack 2 in the medium width direction The position of is maintained. The shift rack 2 meshes with a shift gear 3 as an example of a first gear member, and moves in the medium width direction when the shift gear 3 rotates. The shift gear 3 rotates upon receiving a driving force of a shift motor 4 as an example of a first driving source.

In the drive side support shaft 1, a driven gear 6 as an example of a second transmitted member is supported between the shift rack 2 and the rear support portion U3 e. The driven gear 6 meshes with an intermediate gear 7 as an example of an intermediate transmission member that is long in the front-rear direction. The intermediate gear 7 rotates by receiving a driving force of a registration driving motor 8 as an example of a second driving source. Note that the front and rear lengths of the intermediate gear 7 are set in accordance with the amount of movement of the drive registration roll Rr1 in the medium width direction.
In the drive side support shaft 1, two disk-shaped holding members 9 are supported at an interval in front of the front support portion U3e.

  The driven registration roll Rr2 has a driven side support shaft 11 extending in the front-rear direction. Similar to the drive-side support shaft 1, the driven-side support shaft 11 is supported by the support portion U3e so as to be movable and rotatable in the medium width direction. In the driven side support shaft 11, a disk-shaped held member 12 is supported in front of the front support portion U3e corresponding to the holding member 9 of the drive registration roll Rr1. The held member 12 is held in a state of being sandwiched between the holding members 9. As a result, the driven registration roll Rr2 moves in the medium width direction together with the driving registration roll Rr1.

When the registration drive motor 8 rotates, the drive registration roll Rr1 rotates through the gears 6 and 7, and the driven registration roll Rr2 in contact with the drive registration roll Rr1 also rotates.
When the shift motor 4 rotates in the forward direction, the drive registration roll Rr1 moves forward and the driven registration roll Rr2 also moves forward via the shift gear 3 and the shift rack 2. When the shift motor 4 rotates in the reverse direction, the drive registration roll Rr1 moves rearward and the driven registration roll Rr2 also moves rearward via the shift gear 3 and the shift rack 2.

A shift sensor 13 as an example of a detection member that detects a home position as an example of an initial position of the registration roll Rr is disposed above the registration roll Rr. In FIG. 3, a side sensor 14 for detecting the side edge of the recording sheet S is arranged behind the registration roll Rr as an example of a side edge detection member. Further, an upstream registration sensor 16 as an example of a medium passage detection member and a downstream registration sensor 17 for detecting the positional relationship between the recording sheet S and the registration roll Rr are disposed on the upstream side and the downstream side of the registration roll Rr. ing.
Based on the detection results of the sensors 13 to 17, the registration roll Rr is rotated or stopped to convey the recording sheet S and the medium width until the side edge of the recording sheet S is detected from the initial position. Move in the direction, so-called side shift.
That is, the registration roll Rr according to the first embodiment moves in the width direction when the position in the width direction of the recording sheet S is set to a preset position, and is formed by the visible image forming members Uy + Gy to Uk + Gk. The recording sheet S is conveyed to the secondary transfer area Q4 in accordance with the time when the visual image reaches the secondary transfer area Q4.

(Description of the side guide 18)
In FIG. 3, a side guide 18 as an example of a side edge aligning member is disposed on the upstream side of the registration roll Rr and on the rear side of the sheet conveying path SH2. The side guide 18 extends along the sheet conveyance path SH2 and is configured to be able to contact a side edge in the medium width direction, which is a direction orthogonal to the medium conveyance direction of the recording sheet S conveyed along the sheet conveyance path SH2. Has been.

(Explanation of Crosstrol Rc)
FIG. 5 is an explanatory diagram of the cross-trolling of Example 1, FIG. 5A is an explanatory diagram viewed in the direction of line VA-VA in FIG. 3, and FIG. FIG. 5C is an explanatory diagram of a state where the driving cross-trol is moved to the registration feeding position, and FIG. 5D is an explanatory diagram of a state where the driving cross-trol is moved to the guide feeding position.
In FIG. 3, on the upstream side of the registration roll Rr and on the front side of the side guide 18, three cross rolls Rc as an example of a feeding member are arranged along the side guide 18 at intervals.
In FIG. 5A, each cross-trol Rc includes a driving cross-trol Rc1 as an example of a driving-side feeding member, and a driven cross-trol Rc2 as an example of a driven-side feeding member facing the driving cross-trol Rc1, respectively. Have.

In FIG. 5, each of the drive cross rolls Rc1 is supported by a separate lower turntable 19 provided on the lower side of the sheet conveying path SH2 corresponding to the position of the cross roll Rc.
In addition, since each cross-trol Rc and each lower side turntable 19 are comprised similarly except the point from which an arrangement position differs, in subsequent description, only about the cross-trol Rc and the lower side turntable 19 arrange | positioned on the right side. The detailed explanation of the cross trawl Rc and the lower turntable 19 arranged in the center and the left side will be omitted.

5A and 5C, the lower turntable 19 is rotatably supported by a shaft U3f provided in the image forming apparatus main body U3 at the front and rear central portions.
The lower turntable 19 is formed with a pair of front and rear shaft support portions 19a that rotatably support the drive cross-trol Rc1 corresponding to the rotation center of the lower turntable 19, that is, the position of the axis U3f. Has been. A rack engaging hole 19b as an example of a long hole extending in the front-rear direction is formed in the rear portion of the lower turntable 19. Further, a motor support portion 19c as an example of a support portion of a drive source of the feed member is formed at the front portion of the lower turntable 19.

5A and 5C, the shaft 21 of the driving cross-trol Rc1 is supported on the shaft support portion 19a of the lower turntable 19 so as to be rotatable about the front-rear direction as an axial direction. A driven gear 22 as an example of a driven gear is supported at the front end of the shaft 21.
A feed drive motor 23 as an example of a drive source of the feed member is supported on the motor support portion 19c. A drive gear 24 as an example of a drive gear is supported on the drive shaft 23 a of the feed drive motor 23. The driving gear 24 meshes with the driven gear 22 of the driving cross-trol Rc1. Therefore, when the feed drive motor 23 is driven, the drive cross-trol Rc1 is driven.

In FIG. 5, a lower rack 26 as an example of a plate-shaped transmission member extending in the left-right direction is disposed below the rear side of the lower turntable 19. The lower rack 26 is guided by a guide U3g as an example of a guide member provided in the image forming apparatus main body U3, and is supported so as to be movable in the left-right direction.
5C and 5D, a rack portion 26a as an example of a transmitted portion is formed at the right end portion of the lower rack 26. On the left side of the rack portion 26a, transmission pins 26b, 26c, and 26d, which are examples of transmission portions that protrude upward, are formed corresponding to the positions of the cross trawls Rc.
The transmission pins 26b to 26d are fitted in the rack engagement holes 19b of the lower turntables 19, respectively. As a result, when the lower rack 26 moves in the left-right direction, the rack engaging holes 19b are pushed in the left-right direction by the transmission pins 26b to 26d, and each lower turntable 19 is centered on each axis U3f. Rotate and move.

FIG. 6 is an explanatory view of the cross trol and the nip pressure adjusting member, FIG. 6A is an explanatory view of the cross trol at the contact position, and FIG. 6B is an explanatory view of the cross trol at the separated position.
In FIG. 5A, an upper turntable 27 and an upper rack 28 are arranged on the upper side of the sheet conveying path SH2 corresponding to the lower turntable 19 and the lower rack 26.
On the upper rotary table 27, a driven cross roll Rc2 is arranged opposite to the drive cross roll Rc1.
In FIG. 6A, the driven cross roll Rc2 is rotatable to a nip pressure adjustment member 29 as an example of a contact pressure adjustment member supported by the upper turntable 27, and can be moved closer to and away from the drive cross roll Rc1. It is supported.
That is, the driven cross roll Rc2 is driven by the nip pressure adjusting member 29 to contact the drive cross roll Rc1 and driven to rotate, and the separated position shown in FIG. 6B separated from the drive cross roll Rc1. It is supported so that it can move between. In addition, the driven cross-trol Rc2 is applied with a force that approaches or separates from the driving cross-trol Rc1 by the nip pressure adjusting member 29 at the contact position, and the contact pressure at the time of contact The so-called nip pressure is changed.

Such a nip pressure adjusting member 29 is described in, for example, Japanese Patent Application Laid-Open No. 2005-316336, and is well known in the art, so detailed illustration and description thereof will be omitted.
The driving cross trol Rc1 and the driven cross trol Rc2 constitute the cross trol Rc of Example 1. The cross trol Rc sends the recording sheet S conveyed on the sheet conveyance path SH2 to the downstream side.
The upper rotary table 27 and the upper rack 28 are arranged symmetrically with respect to the lower rotary table 19 and the lower rack 26, and are replaced with members related to the drive source of the feed member such as the feed drive motor 23. Except for the point that the nip pressure adjusting member 29 is supported, the configuration is the same as that of the lower turntable 19 and the lower rack 26, and thus detailed description thereof is omitted.

5A and 5B, the lower gear 31 as an example of the first gear member meshes with the rack portion 26a of the lower rack 26. The lower gear 31 includes a front gear portion 31a that meshes with the rack portion 26a, and a rear gear portion 31b that is integrally formed behind the front gear portion 31a. A driving force is transmitted to the rear gear portion 31b from a position switching motor 32 as an example of a position switching drive source supported by the image forming apparatus main body U3.
5A and 5B, the rack portion 28a of the upper rack 28 is engaged with an upper gear 33 as an example of a second gear member. The upper gear 33 meshes with the front gear portion 31 a of the lower gear 31.

As a result, when the position switching motor 32 rotates forward, the lower gear 31 rotates clockwise as viewed from the front in FIG. 5B, the lower rack 26 moves to the left, and the lower gear 31. The upper gear 33 that is meshed with the gear rotates counterclockwise as viewed from the front, and the upper rack 28 moves to the left.
When the position switching motor 32 rotates in the reverse direction, in FIG. 5B, the lower gear 31 rotates counterclockwise as viewed from the front, the lower rack 26 moves to the right, and the lower gear 31 and The meshed upper gear 33 rotates clockwise as viewed from the front, and the upper rack 28 moves to the right.

That is, when the position switching motor 32 rotates, the upper and lower racks 26 and 28 move in the same direction in the left-right direction, and the lower rotary table 19 and the upper rotary table 27 rotate about the respective axes U3f. 5C, and a position along the direction inclined from the front-rear direction on the left side toward the rear as shown in FIG. 5D.
Therefore, the cross-trol Rc supported by the turntables 19 and 27 has a front-rear direction in which the axial direction of the shaft 21 of the cross-trol Rc is a position along the front-rear direction shown in FIG. Move between positions along the inclined direction.
That is, the cross roll Rc is in a registration feeding position shown in FIG. 5C as an example of a first feeding position for feeding the recording sheet S to the registration roll Rr side and a direction for feeding the recording sheet S to the registration roll Rr side. It is provided so as to be movable between a side feed position shown in FIG. 5D as an example of a second feed position for feeding the recording sheet S in a direction inclined to the side guide 18 side.

When the cross trol Rc is moved to the registration feeding position, the recording sheet S conveyed through the sheet conveyance path SH2 is fed to the registration roll Rr by the cross trol Rc. At this time, if the driving of the registration roll Rr is stopped, the downstream end of the recording sheet S on the downstream side in the medium conveying direction is abutted against the registration roll Rr by the cross roll Rc, and bends to the recording sheet S. A so-called loop is formed, the posture of the recording sheet S is aligned, and the inclination of the recording sheet S, so-called skew, is corrected.
Further, when the cross trol Rc is moved to the side feeding position, the recording sheet S conveyed through the sheet conveyance path SH2 is fed to the side guide 18 side by the cross trol Rc. Then, the side edge of the recording sheet S is brought into contact with the side guide 18 by the cross-trol Rc so that the posture of the recording sheet S is aligned, and the inclination of the recording sheet S, so-called skew is corrected. .
In the cross troll Rc of the first embodiment, the nip pressure when moving to the registration feed position is set to be stronger than the nip pressure when moving to the side feed position. .

(Description of Controller C of Example 1)
FIG. 7 is a block diagram illustrating the functions of the control unit of the image forming apparatus according to the first embodiment.
FIG. 8 is a block diagram illustrating functions provided in the control unit of the image forming apparatus according to the first exemplary embodiment, and is a continuation of FIG.
7 and 8, the controller C is an input / output interface as an example of an input / output signal adjustment unit that performs input / output of signals to / from the outside and adjustment of input / output signal levels, so-called I / O, necessary. Depending on the program stored in the read-only memory, so-called ROM, a random access memory for temporarily storing necessary data, so-called RAM, and the program stored in the ROM. A central processing unit that performs the above-described processing, that is, a computer as an example of a computer having a CPU and a clock oscillator, and implements various functions by executing programs stored in the ROM. Can do.

(Signal input element connected to controller C)
The controller C receives signals from signal input elements such as a user interface UI, a shift sensor 13, a side sensor 14, an upstream registration sensor 16, a downstream registration sensor 17, and the like.
UI: User interface The user interface UI includes a display panel UI0 as an example of a display unit, a copy start key UI1 as an example of a copy start button, a numeric keypad UI2 as an example of a numeric input button, and an example of a copy number input button. A copy number input key UI3, a tray setting key UI4 as an example of a paper feed container setting input button, and the like are provided, and when these are input, a detection signal is input to the controller C.
Note that the tray setting key UI4 according to the first exemplary embodiment sets information about the recording sheets S accommodated in the paper feed trays TR1 to TR4 of the paper feed device U2. That is, as the information of the recording sheets S accommodated in the sheet feeding trays TR1 to TR4, the type of the recording sheet S such as cardboard or plain paper, long side feed, so-called LEF: Long Edge Feed, Short side feed, so-called medium transport direction such as SEF: Short Edge Feed, size of A4, B4, etc. are set.

13: Shift sensor The shift sensor 13 detects whether or not the registration roll Rr has moved to the home position.
14: Side sensor The side sensor 14 detects the presence or absence of the recording sheet S and detects the side edge of the recording sheet S.
16: Upstream registration sensor The upstream registration sensor 16 detects the presence or absence of the recording sheet S, and detects whether or not the recording sheet S has passed the detection position upstream of the registration roll Rr.
17: Downstream registration sensor The downstream registration sensor 17 detects the presence or absence of the recording sheet S, and detects whether or not the recording sheet S has passed the detection position on the downstream side of the registration roll Rr.

(Control element connected to controller C)
The controller C includes a laser drive circuit D, a main motor drive circuit D1, a registration roll drive circuit D2, a shift motor drive circuit D3, a cross-trol drive circuit D4, a nip pressure adjustment drive circuit D5, a position switching motor drive circuit D6, and a power supply circuit. E, connected to other control elements, and outputs their operation control signals.

D: Laser drive circuit The laser drive circuit D controls the latent image forming devices ROSy to ROSk to form a latent image. D1: Main motor driving circuit A main motor driving circuit D1 as an example of a driving circuit for a main driving source is connected to an image carrier Py to Pk and developing units Gy to Gk via a main motor M1 as an example of a main driving source. The developing roll R0, the belt driving roll Rd, the fixing device F, and the like are rotated.
D2: Registration Roll Drive Circuit A registration roll drive circuit D2 as an example of a drive circuit for the registration roll Rr rotationally drives the registration roll Rr via the registration drive motor 8 capable of controlling the rotation speed.

D3: Shift Motor Drive Circuit The shift motor drive circuit D4 as an example of a drive circuit for the shift motor 4 drives the shift motor 4 to move the registration roll Rr in the medium width direction, so-called side shift.
D4: Cross Troll Drive Circuit A cross troll drive circuit D4 as an example of a drive circuit for the cross troll Rc rotates the cross troll Rc via the feed drive motor 23.
D5: Nip Pressure Adjustment Drive Circuit A nip pressure adjustment drive circuit D5 as an example of a drive circuit for the nip pressure adjustment member 29 contacts the driven cross roll Rc2 with the drive cross roll Rc1 via the nip pressure adjustment member 29. The nip pressure of the cloth roll Rc is adjusted.
D6: Position switching motor drive circuit The position switching motor drive circuit D6 as an example of a drive circuit for the position switching motor 32 rotates the position switching motor 32 forward and backward, thereby moving the cross-trol Rc to the registration feed position and the side. Move between feed positions.

E: Power Supply Circuit The power supply circuit E includes a development power supply circuit E1, a charging power supply circuit E2, a transfer roll power supply circuit E3, and a heating roll power supply circuit E4.
E1: Developing power circuit The developing power circuit E1 applies a developing voltage to the developing roll R0 of the developing device G.
E2: Charging power supply circuit The charging power supply circuit E2 applies a charging voltage to the chargers CCy, CCm, CCc, CCk.
E3: Transfer Roll Power Supply Circuit The transfer roll power supply circuit E3 applies a transfer voltage to the primary transfer rolls T1y, T1m, T1c, T1k and the contact roll T2c of the transfer device T1 + B + T2 + CLB.
E4: Heating Roll Power Supply Circuit The heating roll power supply circuit E4 applies heating power to a heater as an example of a heating member of the heating roll Fh of the fixing device F.

(Function of controller C)
The controller C executes processing according to output signals from the signal output elements such as the user interface UI, the shift sensor 13, the side sensor 14, the upstream registration sensor 16, the downstream registration sensor 17, and controls the control elements. It has the following function realizing means for outputting a signal.
C1: Job Control Unit The job control unit C1 as an example of the image forming operation control unit is configured to output the latent image forming devices ROSy to ROSk, the image recording unit U3a, the fixing device F, and the sheet conveyance according to the input of the copy start key UI1. A job as an example of an image forming operation is executed by controlling the operation of the apparatus SU or the like.

C2: Main motor rotation control means A main motor rotation control means C2 as an example of a rotation control means for the main drive source controls the main motor drive circuit D1 to control the image carriers Py to Pk and developing units Gy to Gk. The rotation drive of the fixing device F or the like is controlled.
C3: Power supply circuit control means The power supply circuit control means C3 controls the power supply circuit E to develop the developing roll R0, the chargers CCy, CCm, CCc, CCk, the primary transfer rolls T1y, T1m, T1c, T1k, and the contact roll T2c. The voltage and current supply to the heater of the heating roll Fh of the fixing device F is controlled.

C4: Paper Tray Setting Unit A paper feeding tray setting unit C4 as an example of a paper feeding container setting unit has a setting key input determination unit C4A and a storage sheet storage unit C4B, and each of the paper feeding trays TR1 to TR4. Set up.
C4A: Setting Key Input Discriminating Unit A setting key input discriminating unit C4A as an example of a paper feed container setting button input discriminating unit discriminates whether or not a paper feed tray setting key UI4 has been input.
C4B: Storage Sheet Storage Unit The storage sheet storage unit C4B as an example of the storage medium storage unit stores setting information about the recording sheets S stored in the paper feed trays TR1 to TR4.
The storage sheet storage unit C4B according to the first exemplary embodiment sets the recording sheet S such as cardboard or plain paper as the setting information of the recording sheet S stored in the paper feed trays TR1 to TR4 based on the input of the tray setting key UI4. The type, medium feeding direction such as LEF and SEF, size such as A4 and B4, and the like are stored.

C5: Feeding discriminating unit The feeding discriminating unit C5 determines whether or not the recording sheet S satisfies a feeding condition for discriminating whether or not the recording sheet S transported through the sheet transport path SH2 is to be sent to the side guide 18 side. Is determined.
In the feeding determination unit C5 of the first embodiment, as an example of the feeding condition, a condition is set in advance that the recording sheet S is longer at the side end than at the downstream end. The feed determination unit C5 according to the first exemplary embodiment determines whether the setting of the sheet feeding trays TR1 to TR4 to be fed is SEF based on the storage information of the storage sheet storage unit C4B. Then, it is determined whether or not the recording sheet S satisfies the feeding condition of the first embodiment, that is, the condition that the recording sheet S has a longer side edge than the downstream end.

C6: Sheet Passing Discriminating Unit A sheet passing discriminating unit C6 as an example of a medium passing discriminating unit detects passage of the recording sheet S conveyed through the sheet conveying path SH2 based on the detection results of the upstream registration sensor 16 and the downstream registration sensor 17. Determine.
When the detection signal from the upstream registration sensor 16 changes from the non-detection state to the detection state, the sheet passing determination unit C6 according to the first exemplary embodiment is configured such that the downstream end of the recording sheet S, that is, the so-called front end of the recording sheet S is the upstream registration sensor 16. It is determined that the detection area has been passed. Further, the sheet passage determining unit C6 according to the first exemplary embodiment determines that the front end of the recording sheet S has passed the detection area of the downstream registration sensor 17 when the detection signal from the downstream registration sensor 17 changes from the non-detection state to the detection state. Determine. Further, in the sheet passing determination means C6 of the first embodiment, when the detection signal from the downstream registration sensor 17 changes from the detection state to the non-detection state, the upstream end of the recording sheet S, that is, the so-called trailing end of the recording sheet S is It is determined that the detection area of the downstream registration sensor 17 has passed.

C7: Loop formation time passage determination means Loop formation time passage determination means C7 as an example of curve formation time passage determination means includes loop formation time storage means C7A and loop timer TM1, and is an example of curve formation time. It is determined whether or not the loop formation time t1 has elapsed.
C7A: Loop formation time storage means The loop formation time storage means C7A as an example of the curve formation time storage means is used as an example of the curve formation time after the upstream registration sensor 16 detects the passage of the downstream end of the recording sheet S. The loop formation time t1, which is the time until the trawl Rc stops, is stored.
The loop formation time t1 of the first embodiment is measured in advance by experiments or the like, and the downstream end of the recording sheet S is abutted against the registration roll Rr to form a loop, and the inclination of the recording sheet S, so-called skew, is corrected. Sufficient time is preset.
TM1: Loop Timer A loop timer TM1 as an example of a time measuring means for the curve formation time counts the loop formation time t1 after the upstream registration sensor 16 detects the passage of the downstream end of the recording sheet S.
The loop timer TM1 according to the first embodiment starts measuring the loop formation time t1 when the sheet passage determining unit C6 determines that the downstream end of the recording sheet S has passed the detection area of the upstream registration sensor 16, and the loop formation time t1 is started. When the time t1 elapses, the time is up.

C8: Cross-trolling control means A cross-trolling control means C8 as an example of a feeding member control means includes a feed position switching means C8A, a closted contact / separation control means C8B, and a crusty drive control means C8C. When it is determined by means C5 that the recording sheet S satisfies the feeding condition, the crossing roll Rc is controlled to send the recording sheet S to the side member 18 side, and the recording sheet S A side end is brought into contact with the side guide 18. The cross-trolling control unit C8 controls the cross-trolling Rc to control the recording sheet S when the recording determining unit C5 determines that the recording sheet S does not satisfy the feeding condition. The sheet is sent to the registration roll Rr, and the downstream end of the recording sheet S is abutted against the registration roll Rr.

C8A: Feed position switching means The feed position switching means C8A drives the position switching motor 32 via the position switching motor drive circuit D6 to rotate the turntables 19 and 27, and the cross trawl Rc is changed to FIG. 5C. It is moved between the register feeding position shown and the side feeding position shown in FIG. 5D.
The feed position switching unit C8A according to the first exemplary embodiment moves the cross troll Rc to the side feed position when the feed determination unit C5 determines that the recording sheet S satisfies the feed condition.
Further, the feed position switching means C8A of Example 1 moves the cross troll Rc to the registration feed position when the feed discrimination means C5 determines that the recording sheet S does not satisfy the feed conditions.

C8B: Crost contact / separation control means The crosto contact / separation control means C8B as an example of the feed member contact / separation control means drives the nip pressure adjustment member 29 via the nip pressure adjustment drive circuit D5, thereby driving the driven cross roll Rc2. Is moved closer to and away from the driving cross-roll Rc1 to adjust the nip pressure of the cross-trol Rc or to move the cross-roll Rc apart.
The crossed contact / separation control means C8B of Embodiment 1 shows the driven crosstrol Rc2 when the recording sheet S is sent downstream when the crossing roll Rc is moved to the side feed position by the feed position switching means C8A. It moves to the contact position shown to 6A, and adjusts a nip pressure to the weak state set beforehand. The clotht contact / separation control unit C8B according to the first exemplary embodiment performs the following operation when the downstream end of the recording sheet S is sandwiched between the registration rolls Rr and it is determined that the downstream end has passed the detection area of the downstream registration sensor 17. Rc2 is moved to the separation position shown in FIG. 6B to separate the cross troll Rc.

Further, the crossed contact / separation control means C8B of the first embodiment is driven by the driven crosstrol Rc2 when the recording sheet S is sent downstream when the crossing roll Rc is moved to the registration feeding position by the feed position switching means C8A. Is moved to the contact position shown in FIG. 6A to adjust the nip pressure to a preset strong state. The clotht contact / separation control unit C8B according to the first exemplary embodiment performs the following operation when the downstream end of the recording sheet S is sandwiched between the registration rolls Rr and it is determined that the downstream end has passed the detection area of the downstream registration sensor 17. Rc2 is moved to the separation position shown in FIG. 6B to separate the cross troll Rc.
In Example 1, a weak nip pressure causes a small frictional force between the cross-trol Rc and the recording sheet S, and the recording sheet S is fed by the cross-trol Rc, and the side edge of the recording sheet S is directed to the side guide 18. In the abutted state, the pressure is set such that the cross roll Rc slides against the recording sheet S having rigidity, that is, stiffness, and the recording sheet S can be conveyed downstream without being bent.
In Example 1, the strong nip pressure causes a large frictional force between the cross roll Rc and the recording sheet S. The recording sheet S is fed by the cross roll Rc, and the downstream end of the recording sheet S hits the registration roll Rr. When the contact is applied, the pressure is set such that the recording sheet S that is abutted is conveyed downstream and a loop can be formed on the recording sheet S.

C8C: Crossed Drive Control Unit A crossed drive control unit C8C as an example of a drive control unit for the feed member drives and drives the drive crosstrol Rc1 by driving and stopping the feed drive motor 23 via the crosstrol drive circuit D4. Or stop.
When the cross roll Rc is moved to the side feed position by the feed position switching means C8A, the cross drive control means C8C of Embodiment 1 drives the drive cross roll Rc1 when feeding the recording sheet S to the downstream side. . The crossed drive control unit C8C according to the first exemplary embodiment drives the driven crosstrol Rc1 when it is determined that the downstream end of the recording sheet S is sandwiched between the registration rolls Rr and the downstream end has passed the detection area of the downstream registration sensor 17. Stop.
Further, the crossed drive control means C8C of the first embodiment, when the cross roll Rc is moved to the registration feed position by the feed position switching means C8A, drives the drive cross roll Rc1 when the recording sheet S is sent downstream. Drive. Then, when it is determined that the loop formation time t1 has elapsed, the crossed drive control unit C8C according to the first embodiment stops the drive crosstrol Rc1.

C9: Registration Roll Control Unit The registration roll control unit C9, which is an example of a control unit for the conveyance timing adjusting member, includes a side shift control unit C9A and a registration roll drive control unit C9B. The registration roll Rr is side-shifted or rotationally driven. Or
C9A: Side shift control means Side shift control means C9A as an example of movement control means for the conveyance timing adjusting member has registration home position determination means C9A1 and side end position determination means C9A2, and includes a shift motor drive circuit D3. By driving the shift motor 4 therethrough, the registration roll Rr is moved in the axial direction of the registration roll Rr, that is, side-shifted.
When the recording sheet S is conveyed, the side shift control unit C9A according to the first embodiment moves the registration roll Rr to a home position as an example of an initial position. The side shift control means C9A of Example 1 detects the side edge of the recording sheet S by the side sensor 14 when it is determined that the downstream edge of the recording sheet S has passed the detection area of the downstream registration sensor 17. Until the registration roll Rr is side-shifted.

C9A1: Registration home position determination means The registration home position determination means C9A1, which is an example of the initial position determination means of the conveyance timing adjustment member, determines whether or not the registration roll Rr has moved to the home position based on the detection result of the shift sensor 13. Is determined.
C9A2: Side edge position determination means The side edge position determination means C9A2 determines, based on the detection result of the side sensor 14, whether or not the side edge of the recording sheet S has reached the detection area of the side sensor 14. It is determined whether or not the position of the side edge of the recording sheet S has moved to a preset reference position in accordance with the image transferred in the secondary transfer region Q4.

C9B: Registration Roll Drive Control Unit A registration roll drive control unit C9B as an example of a drive control unit for the conveyance timing adjusting member includes a conveyance timing determination unit C9B1, and drives the registration drive motor 8 via the registration roll drive circuit D2. Then, the registration roll Rr is driven and stopped.
The registration roll drive control means C9B according to the first embodiment drives the registration roll Rr when the cross roll Rc moves to the side feed position. On the other hand, the registration roll drive control means C9B of Embodiment 1 stops the registration roll Rr when the cross roll Rc moves to the registration feeding position, and drives the registration roll Rr when the loop formation time t1 has elapsed. .
The registration roll drive control unit C9B according to the first exemplary embodiment stops the registration roll Rr when it is determined that the downstream end of the recording sheet S has passed the detection area of the downstream registration sensor 17 after driving the registration roll Rr. Then, the registration roll drive control means C9B of Example 1 drives the registration roll Rr when it is determined that it is time to transport the recording sheet S to the secondary transfer region Q4. Then, the registration roll drive control unit C9B according to the first embodiment stops the registration roll Rr when the job ends.
C9B1: Conveying Time Discriminating Unit The conveying time discriminating unit C9B1 discriminates whether or not it is the conveying time that is the time for conveying the recording sheet S from the registration roll Rr to the secondary transfer area Q4.

(Explanation of flowchart of Example 1)
Next, a processing flow of the image forming apparatus U according to the first exemplary embodiment of the present invention will be described with reference to a flowchart, that is, a so-called flowchart.
(Description of Flowchart of Skew Correction Processing in Embodiment 1)
FIG. 9 is a flowchart of skew correction processing as an example of medium tilt correction processing according to the first embodiment of the present invention.
The process of each step ST of the flowchart of FIG. 9 is performed according to a program stored in the controller C of the image forming apparatus U. In addition, this process is executed in parallel processing in parallel with other various processes of the image forming apparatus U.
The flowchart shown in FIG. 9 is started when the image forming apparatus U is turned on.

In ST1 of FIG. 9, it is determined whether or not a job as an example of an image forming operation has been started. If yes (Y), the process proceeds to ST2. If no (N), ST1 is repeated.
In ST2, it is determined whether or not the recording sheets S accommodated in the paper feed trays TR1 to TR4 to be fed are fed by SEF. If yes (Y), the process proceeds to ST3. If no (N), the process proceeds to ST4.
In ST3, the side edge alignment process is called and executed, and the process returns to ST1.
In ST4, the downstream end alignment process is called and executed, and the process returns to ST1.

(Description of Flowchart of Side Alignment Processing in Embodiment 1)
FIG. 10 is a flowchart of the side edge alignment process according to the first embodiment of the present invention.
In ST11 of FIG. 10, the cross troll Rc is moved to the side feed position, and the process proceeds to ST12.
In ST12, the registration roll Rr is moved to the home position, and the process proceeds to ST13.
In ST13, the following processes (1) to (3) are executed, and the process proceeds to ST14.
(1) The driven cross roll Rc2 is moved to the contact position, and the nip pressure is adjusted to be weak.
(2) The cross troll Rc is driven.
(3) The registration roll Rr is driven.
In ST14, it is determined whether or not the downstream end of the recording sheet S transported through the sheet transport path SH2, that is, the so-called front end is detected by the downstream registration sensor 17. If yes (Y), the process proceeds to ST15, and if no (N), ST14 is repeated.

In ST15, the following processes (1) to (3) are executed, and the process proceeds to ST16.
(1) The driven cross troll Rc2 is moved to the separation position.
(2) The driving of the cross troll Rc is stopped.
(3) Stop the driving of the registration roll Rr.
In ST16, a side shift of the registration roll Rr is started, and the process proceeds to ST17.
In ST17, it is determined whether or not the side edge of the recording sheet S is detected by the side sensor 14. If yes (Y), the process proceeds to ST18, and if no (N), ST17 is repeated.
In ST18, the side shift of the registration roll Rr is completed, and the process proceeds to ST19.
In ST19, it is determined whether or not it is time to transport the recording sheet S to the secondary transfer region Q4. If yes (Y), the process proceeds to ST20. If no (N), ST19 is repeated.

In ST20, the registration roll Rr is driven, and the process proceeds to ST21.
In ST21, it is determined whether or not the upstream end of the recording sheet S, the so-called rear end, has been detected by the downstream registration sensor 17. If yes (Y), the process proceeds to ST22, and if no (N), ST21 is repeated.
In ST22, it is determined whether or not the job is finished. If yes (Y), the process proceeds to ST23, and, if no (N), the process returns to ST12.
In ST23, the driving of the registration roll Rr is stopped, the side edge alignment process is terminated, and the process returns to the skew correction process.

(Description of Flowchart of Downstream Edge Alignment Processing in Embodiment 1)
FIG. 11 is a flowchart of downstream end alignment processing according to the first embodiment of the present invention.
In ST31 of FIG. 11, the cross troll Rc is moved to the registration feed position, and the process proceeds to ST32.
In ST32, the registration roll Rr is moved to the home position, and the process proceeds to ST33.
In ST33, the following processes (1) to (3) are executed, and the process proceeds to ST34.
(1) The driven cross roll Rc2 is moved to the contact position to adjust the nip pressure strongly.
(2) The cross troll Rc is driven.
(3) Stop the driving of the registration roll Rr.
In ST34, it is determined whether or not the downstream end of the recording sheet S conveyed on the sheet conveyance path SH2, that is, the so-called front end is detected by the upstream registration sensor 16. If yes (Y), the process proceeds to ST35, and if no (N), ST34 is repeated.

In ST35, the loop formation time t1 is set, and the process proceeds to ST36.
In ST36, it is determined whether or not the loop formation time t1 has elapsed. If yes (Y), the process proceeds to ST37, and if no (N), ST36 is repeated.
In ST37, the following processes (1) and (2) are executed, and the process proceeds to ST38.
(1) Stop the driving of the cross troll Rc.
(2) Stop driving the registration roll Rr.
In ST38, it is determined whether or not the downstream end of the recording sheet S transported through the sheet transport path SH2, that is, the so-called front end is detected by the downstream registration sensor 17. If yes (Y), the process proceeds to ST39, and if no (N), ST38 is repeated.

In ST39, the following processes (1) and (2) are executed, and the process proceeds to ST40.
(1) The driven cross troll Rc2 is moved to the separation position.
(2) Stop driving the registration roll Rr.
In ST40 to ST45, the same processing as ST16 to ST21 of the side edge alignment processing is executed. In ST45, if yes (Y), the process proceeds to ST46.
In ST46, it is determined whether or not the job is finished. If yes (Y), the process proceeds to ST47, and, if no (N), the process returns to ST32.
In ST47, the driving of the registration roll Rr is stopped, the downstream end alignment process is terminated, and the process returns to the skew correction process.

(Operation of Example 1)
In the image forming apparatus U according to the first embodiment having the above-described configuration, when a job is started, the recording sheet S is supplied from the paper feed trays TR1 to TR4 to the paper feed path SH1 by SEF or LEF. The recording sheet S supplied to the sheet supply path SH1 is corrected in the orientation of the recording sheet S in the sheet transport path SH2, so-called skew, and an image is recorded in the secondary transfer area Q4, and is discharged to the discharge tray TH1. The
In the image forming apparatus U according to the first embodiment, when the skew is corrected, the skew correction processing ST2 to ST4 is executed to determine whether the recording sheet S satisfies the feeding condition, that is, at the downstream end of the recording sheet S. The side edge alignment process or the downstream edge alignment process is executed depending on whether the side edge is longer than that.

FIG. 12 is an explanatory diagram when the cross trolling is moved to the side feeding position, FIG. 12A is an explanatory diagram before the recording sheet S is conveyed, and FIG. 12B is an explanatory diagram subsequent to FIG. FIG. 12C is an explanatory diagram subsequent to FIG. 12B, an explanatory diagram when the recording sheet is in contact with the side guide, and FIG. 12D is an explanatory diagram subsequent to FIG. 12E is an explanatory diagram when the downstream end of the sheet is detected by the downstream registration sensor, FIG. 12E is an explanatory diagram subsequent to FIG. 12D, and an explanatory diagram when the side end of the recording sheet is detected by the side sensor.
When the side edge is longer than the downstream edge of the recording sheet S, that is, when it is determined that the recording sheet S is fed by SEF, the side edge alignment process is executed.

In FIG. 12A, by the side end alignment processes ST11 to ST12, the cross roll Rc moves to the side feed position inclined toward the side guide 18 with respect to the transport direction, and the registration roll Rr moves to the home position. Then, the cross-roll Rc and the registration roll Rr are driven by the side edge aligning process ST13, and as shown in FIG. As shown in FIG. 12C, the side edge of the recording sheet S comes into contact with the side guide 18 and the side edges are aligned. That is, the skew of the recording sheet S is corrected.
Here, the nip pressure of the cross roll Rc is adjusted to be weak, and the recording sheet S is in a state in which the side edge is in contact with the side guide 18 and is in contact with the side guide 18 without being bent. Conveyed to the side.

  Then, the recording sheet S is sandwiched between the registration rolls Rr by the side edge alignment processing ST14 to ST18, and when the downstream end of the recording sheet S is detected by the downstream registration sensor 17, as shown in FIG. The driving is stopped, the side shift is performed, and the recording sheet S is moved to the reference position shown in FIG. 12E. When the conveyance time for conveying the recording sheet S to the secondary transfer region Q4 is reached by the side edge alignment processing ST19 to ST21, the registration roll Rr is driven to convey the recording sheet S, and the skew-corrected recording sheet. An image is recorded in S.

FIG. 13 is an explanatory diagram when the cross-trol is moved to the registration feeding position, FIG. 13A is an explanatory diagram before the recording sheet S is conveyed, and FIG. 13B is an explanatory diagram subsequent to FIG. FIG. 13C is an explanatory diagram subsequent to FIG. 13B, an explanatory diagram when the recording sheet is in contact with the registration roll, and FIG. 13D is an explanatory diagram subsequent to FIG. 13C. 13E is an explanatory diagram when the downstream registration sensor is detected by the downstream registration sensor, and FIG. 13E is an explanatory diagram subsequent to FIG. 13D and an explanatory diagram when the side edge of the recording sheet is detected by the side sensor.
When the side edge is shorter than the downstream edge of the recording sheet S, that is, when it is determined that the recording sheet S is fed by LEF, the downstream edge alignment process is executed.

In FIG. 13A, the cross-trol Rc moves to the registration feeding position along the transport direction and the registration roll Rr moves to the home position by ST31 to ST32 of the downstream end alignment processing. Then, by the downstream end alignment processing ST33 to ST36, the cross roll Rc is driven in a state where the registration roll Rr is stopped, and when the recording sheet S is conveyed through the sheet conveying path SH2 as shown in FIG. S is sent to the registration roll Rr side by the cross-trol Rc. Then, as shown in FIG. 13C, the downstream end of the recording sheet S is abutted against the stopped registration roll Rr by the cross roll Rc.
Here, the nip pressure of the cross roll Rc is strongly adjusted, and the recording sheet S is sent to the downstream side by the cross roll Rc even when the downstream end is abutted against the registration roll Rr. Therefore, a loop is formed in the recording sheet S, and the downstream ends of the recording sheets S are aligned. That is, the skew of the recording sheet S is corrected.

  Then, by ST37 to ST39 of the downstream end alignment process, the cross roll Rc is stopped, the registration roll Rr is driven, and the downstream end of the recording sheet S is sandwiched between the registration rolls Rr, and as shown in FIG. When the downstream registration sensor 17 is detected by the downstream registration sensor 17, a process similar to the side edge alignment process is performed, and an image is recorded on the recording sheet S with the skew corrected.

  Generally, the recording sheet S is made to be a member Rr, such as a configuration in which the downstream end of the recording sheet S abuts against the registration roll Rr to correct skew, or a configuration in which the side end of the recording sheet S is brought into contact with the side guide 18 to correct skew. In the configuration in which the skew is corrected by being brought into contact with 18, suitable skew correction accuracy can be obtained. However, in the configuration in which the recording sheet S is in contact with the members Rr, 18, the skew correction accuracy differs depending on the type of the recording sheet S, the length of the end of the recording sheet S in contact with the members Rr, 18, and the like, and the registration roll Rr. In the case where the skew is corrected only by a configuration that abuts against the side guide or the skew is corrected only by a configuration that contacts the side guide 18, if the side of the recording sheet S that is in contact is short, depending on the recording sheet S, a sufficient skew may occur. Correction accuracy may not be obtained.

For example, as in Patent Document 1, in the configuration in which the recording sheet S is sent to the side guide by changing the inclination angle of the skew roll according to the recording sheet S, the skew is sufficient when the side end is too short. Correction accuracy may not be obtained.
On the other hand, as in Patent Document 2, the configuration in which the skew is corrected by rotating the recording sheet S with respect to the conveyance direction with a pair of right and left correction rollers without bringing the ends of the recording sheet S into contact with the member and aligning them. The adjustment of the rotation of the right correction roller pair and the rotation of the left correction roller pair is complicated, and the skew correction accuracy is likely to vary. Compared with the case where the recording sheet S is brought into contact with the members Rr and 18, the skew The correction accuracy is difficult to stabilize.

In contrast, in the image forming apparatus U according to the first exemplary embodiment, the recording sheet S fed by SEF is brought into contact with the side guide 18 to correct the skew, and the recording sheet S fed by LEF is corrected. The skew is corrected by abutting against the registration roll Rr, and not the short side of the recording sheet S being conveyed, but the long side having higher correction accuracy than the short side is abutted against the side guide 18 or the registration roll Rr. Is corrected.
Therefore, as in the prior art, the recording sheet S is rotated without being in contact with the member, and the skew is corrected, or the recording sheet S is brought into contact with only one of the side guide 18 or the registration roll Rr. In the image forming apparatus U according to the first exemplary embodiment, the skew of the recording sheet S is corrected with higher accuracy than when the skew is corrected.

Next, a second embodiment of the present invention will be described. In the description of the second embodiment, components corresponding to the components of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. To do.
This embodiment is different from the first embodiment in the following points, but is configured in the same manner as the first embodiment in other points.

(Description of sheet conveyance path SH2)
FIG. 14 is an explanatory diagram of the sheet conveyance path of the second embodiment and corresponds to FIG. 3 of the first embodiment.
FIG. 15 is an explanatory diagram of the cross-trolling of Example 2, FIG. 15A is a diagram corresponding to FIG. 5A of Example 1, FIG. 15B is an explanatory diagram of a state where the pre-registration roll has moved to the contact position, and FIG. It is explanatory drawing of the state which separated.
14 and 15, in the image forming apparatus U according to the second embodiment, the lower rotary table 19, the lower rack 26, the upper rotary table 27, the upper rack 28, the position switching motor 32, and the gears 31, 33 is omitted.
In addition, the image forming apparatus U according to the second embodiment has a cross troll Rc ′ as an example of a second conveying member instead of the cross troll Rc as an example of a feeding member according to the first embodiment.
The cross trol Rc ′ is configured in the same manner as the cross trol Rc of the first embodiment except that the cross trol Rc ′ is directly supported by the image forming apparatus main body U3 instead of the rotary tables 19 and 27. Note that the crostor Rc ′ of the second embodiment is supported in a state corresponding to the side feed position of the first embodiment.

  The cloth roll Rc ′ according to the second embodiment has a cloth contact position as an example of a second contact position capable of contacting the recording sheet S conveyed through the sheet conveyance path SH2 and a second distance separated from the recording sheet S. It is configured to be movable between a clost separation position as an example of the separation position. When the cloth roll Rc ′ is held at the cloth contact position, the cloth roll Rc ′ feeds the recording sheet S conveyed through the sheet conveyance path SH2 to the side guide 18 side.

14 and 15, a pre-registration roll Rpr as an example of a first conveying member is disposed in front of the right cross roll Rc and upstream of the registration roll Rr.
The pre-registration roll Rpr includes a driving pre-registration roll Rpr1 as an example of a driving-side first conveyance member and a driven pre-registration roll Rpr2 as an example of a driven-side first conveyance member.
The drive pre-registration roll Rpr1 is rotatably supported by the transport member support portion U3h1 of the lower support portion U3h. The drive pre-registration roll Rpr1 is driven to rotate by receiving a driving force from a pre-registration drive motor 41 as an example of a drive source of the pre-registration roll Rpr.

15B and 15C, the driven pre-registration roll Rpr2 is rotatably supported by the upper support portion U3h via a link 42 as an example of a swing member.
The link 42 has a shape extending in the left-right direction, and is rotatably supported by a link support portion U3h2 as an example of a swing member support portion provided in the upper support portion U3h. At the left end of the link 42, a spring support portion 42a as an example of an urging member support portion is formed. On the right side of the spring support portion 42a, a roll support portion 42b as an example of a conveying member support portion is formed. A supported portion 42c that is rotatably supported by the link support portion U3h2 is formed on the right side of the roll support portion 42b. At the right end of the link 42, a plunger support portion 42d as an example of a drive member support portion is formed.

A tension spring 43 as an example of an urging member is supported between the spring support portion 42a and the upper support portion U3h. A driven pre-registration roll Rpr2 is rotatably supported by the roll support portion 42b. Further, the plunger support portion 42d supports a plunger 44a as an example of a movable portion of a solenoid 44 as an example of an electromagnetic drive member, and the main body 44b of the solenoid 44 is supported by an upper support portion U3h.
When the solenoid 44 is energized, the plunger 44a moves upward, the right end of the link 42 is pulled upward and the left end of the link 42 moves downward against the tension of the tension spring 43. As a result, the driven pre-registration roll Rpr2 moves downward and contacts the drive pre-registration roll Rpr1. When the solenoid 44 is in a non-energized state, it is pulled by the tension spring 43 and the left end of the link 42 is pulled up. As a result, the driven pre-registration roll Rpr2 moves upward and is separated from the drive pre-registration roll Rpr1.

That is, the pre-registration roll Rpr according to the second embodiment includes a pre-registration contact position illustrated in FIG. 15B as an example of a first contact position that can contact the recording sheet S conveyed on the sheet conveyance path SH2, and the recording sheet S. It is configured to be movable between a pre-registration separation position shown in FIG. 15C as an example of a first separation position to be separated. When the pre-registration roll Rpr is held at the pre-registration contact position, the recording sheet S is sent to the registration roll Rr side.
The crossing roll Rc ′ and the pre-registration roll Rpr constitute a feed member Rc ′ + Rpr of Example 2.

(Description of Controller C of Example 2)
FIG. 16 is a block diagram illustrating the functions of the control unit of the image forming apparatus according to the second embodiment, and corresponds to FIG. 7 according to the first embodiment.
FIG. 17 is a block diagram illustrating functions provided in the control portion of the image forming apparatus according to the second embodiment, and is an explanatory diagram subsequent to FIG.
(Control element connected to controller C)
In the controller C of the second embodiment, the position switching drive circuit D6 of the first embodiment is omitted. The controller C of the second embodiment is connected to the solenoid driving circuit D7 and the pre-registration driving circuit D8 in addition to the control elements D to D5 and E of the first embodiment, and outputs their operation control signals. ing.
D7: Solenoid drive circuit A solenoid drive circuit D7 as an example of a drive circuit for the solenoid 44 is configured to place the pre-registration roll Rpr between the pre-registration contact position and the pre-registration separation position by setting the solenoid 44 to an energized state or a non-energized state. Move.
D8: Pre-registration Drive Circuit The pre-registration drive circuit D8 as an example of a drive circuit for the pre-registration roll Rpr rotates the pre-registration roll Rpr via the pre-registration drive motor 41.

(Function of the controller C)
The controller C according to the second embodiment includes a feeding member control unit C10 according to the second embodiment instead of the cross-trolling control unit C8 as an example of the feeding member control unit according to the first embodiment.
C10: Feed Member Control Unit The feed member control unit C10 includes a cross roll control unit C10A and a pre-registration roll control unit C10B, and controls driving and contact separation of the feed member Rc ′ + Rpr.
The feeding member control means C10 of Example 2 moves the pre-registration roll Rpr to the pre-registration separation position and the cross when the recording judgment sheet C5 determines that the recording sheet S satisfies the feeding condition. The trawl Rc is moved to the cross contact position. Further, the feeding member control means C10 of Example 2 moves the cross-trol Rc to the cross-separated position when the feeding discrimination means C5 determines that the recording sheet S does not satisfy the feeding conditions. The pre-registration roll Rpr is moved to the pre-registration contact position.

C10A: Cross-trolling control means A cross-trolling control means C10A as an example of a control means for the second conveying member has a clost contact / separation control means C10A1 and a crossed drive control means C10A2. When it is determined that the recording sheet S satisfies the feeding condition, the cross roll Rc ′ is moved to the cross contact position, and the recording sheet S does not satisfy the feeding condition by the feeding determination unit C5. If it is determined, the cross trol Rc 'is moved to the cross separation position.

C10A1: Crossed contact / separation control means The crossed contact / separation control means C10A1 according to the second embodiment moves the recording sheet S to the downstream side when the feeding determination means C5 determines that the recording sheet S satisfies the feeding condition. At the time of feeding, the driven cross roll Rc2 is moved to the cross contact position, and the nip pressure is adjusted to a preset weak state. The cross contact / separation control unit C10A1 according to the second exemplary embodiment performs the following operation when the downstream end of the recording sheet S is sandwiched between the registration rollers Rr and it is determined that the downstream end has passed the detection area of the downstream registration sensor 17. Rc2 is moved to the crossed separation position to separate the crosstrol Rc ′.
In addition, the clost contact / separation control unit C10A1 according to the second embodiment moves the driven cross trol Rc2 to the clos-separation position when the feeding determination unit C5 determines that the recording sheet S does not satisfy the feeding condition. Then, the cross trol Rc ′ is separated.

C10A2: Crossed drive control means The crossed drive control means C10A2 of Embodiment 2 sends the recording sheet S to the downstream side when the feeding discrimination means C5 determines that the recording sheet S satisfies the feeding condition. At this time, the drive cross-trol Rc1 is driven. Then, when the downstream end of the recording sheet S is sandwiched between the registration rolls Rr and it is determined that the downstream end has passed the detection area of the downstream registration sensor 17, the crossed drive control unit C10A2 of Example 2 drives the crossed drive control Rc1. Stop.
The cross drive control means C10A2 according to the second embodiment stops the drive cross roll Rc1 when the feed determination means C5 determines that the recording sheet S does not satisfy the feed conditions.

C10B: Pre-registration roll control means A pre-registration roll control means C10B as an example of a control means for the first conveying member has a pre-registration contact / separation control means C10B1 and a pre-registration drive control means C10B2, and the feed discrimination means C5 When it is determined that the recording sheet S satisfies the feeding condition, the pre-registration roll Rpr is moved to the pre-registration separation position, and the recording sheet S does not satisfy the feeding condition by the feeding determination unit C5. When it is determined, the pre-registration roll Rpr is moved to the pre-registration contact position.

C10B1: Pre-registration contact / separation control means The pre-registration contact / separation control means C10B1, which is an example of the first conveying member contact / separation control means, drives the solenoid 44 via the solenoid drive circuit D7, thereby driving the driven pre-registration roll Rpr2. The pre-registration roll Rpr is moved between the pre-registration contact position and the pre-registration separation position by being moved closer to and away from the drive pre-registration roll Rpr1.
The pre-registration contact / separation control unit C10B1 according to the second exemplary embodiment moves the pre-registration roll Rpr to the pre-registration separation position when the feeding determination unit C5 determines that the recording sheet S satisfies the feeding condition.
Further, the pre-registration contact / separation control unit C10B1 according to the second embodiment is configured so that the pre-registration roll is used when the recording sheet S is fed when the feeding determination unit C5 determines that the recording sheet S does not satisfy the feeding condition. Rpr is moved to the pre-registration contact position. The pre-registration contact / separation control unit C10B1 according to the second exemplary embodiment performs the following operation when the downstream end of the recording sheet S is sandwiched between the registration rolls Rr and it is determined that the downstream end has passed the detection region of the downstream registration sensor 17. The registration roll Rpr2 is moved to the pre-registration separation position to separate the pre-registration roll Rpr.

C10B2: Pre-registration drive control means The pre-registration drive control means C10B2 as an example of the drive control means for the first transport member drives and stops the pre-registration drive motor 41 via the pre-registration roll drive circuit D8, thereby driving the pre-registration roll Rpr1. Is driven or stopped.
The pre-registration drive control means C10B2 of Example 2 stops the drive of the drive pre-registration roll Rpr1 when the feed determination means C5 determines that the recording sheet S satisfies the feed condition.
The pre-registration drive control means C10B2 according to the second embodiment is driven when the recording sheet S is sent downstream when the feeding determination means C5 determines that the recording sheet S does not satisfy the feeding condition. The pre-registration roll Rpr1 is driven. Then, the pre-registration drive control unit C10B2 of the second embodiment stops the drive pre-registration Rpr1 when it is determined that the loop formation time t1 has elapsed.

(Explanation of flowchart of Example 2)
Next, a processing flow of the image forming apparatus U according to the second exemplary embodiment of the present invention will be described with reference to a flowchart.
(Description of Flowchart of Skew Correction Processing in Embodiment 2)
In the skew correction processing of the second embodiment, in ST3 and ST4, instead of the side edge alignment processing of the first embodiment or the downstream edge alignment processing of the first embodiment, the side edge alignment processing of the second embodiment or the downstream end of the second embodiment. Since the same processing as the skew correction processing of the first embodiment is executed except that the alignment processing is called, detailed description thereof is omitted.

(Description of Flowchart of Side Edge Alignment Processing in Embodiment 2)
FIG. 18 is a flowchart of the side edge alignment process according to the second embodiment of the present invention, and corresponds to FIG. 10 according to the first embodiment.
In the side edge aligning process of the second embodiment, ST11 ′ is executed instead of ST11 of the side edge process of the first embodiment. In the side edge aligning process of the second embodiment, the same processes as the side edge process of the first embodiment are executed except for ST11 ′. Therefore, only ST11 ′ will be described, and descriptions of the other steps ST12 to ST23 will be omitted. To do.
In ST11 ′ of FIG. 18, the pre-registration roll Rpr is moved to the pre-registration separation position, and the process proceeds to ST12.

(Description of Flowchart of Downstream Edge Alignment Processing in Embodiment 2)
FIG. 19 is a flowchart of downstream end alignment processing according to the second embodiment of the present invention, and corresponds to FIG. 11 according to the first embodiment.
The downstream end alignment process of the second embodiment is performed except that ST31 ′, ST33 ′, ST37 ′, and ST39 ′ are executed in place of ST31, ST33, ST37, and ST39 of the downstream end alignment process of the first embodiment. Processing similar to the downstream end alignment processing in Example 1 is executed.

In ST31 ′ in FIG. 19, the cross-trol Rc ′ is moved to the cross-separation position, and the process proceeds to ST32.
In ST32, the same process as ST32 of the first embodiment is executed, and the process proceeds to ST33 '.
In ST33 ′, the following processes (1) to (3) are executed, and the process proceeds to ST34.
(1) The driven pre-registration roll Rpr2 is moved to the pre-registration contact position.
(2) Drive the pre-registration roll Rpr.
(3) Stop the driving of the registration roll Rr.
In ST34 to ST36, the same processing as ST34 to ST36 of the first embodiment is executed. In ST36, if yes (Y), the process proceeds to ST37 '.

In ST37 ′, the following processes (1) and (2) are executed, and the process proceeds to ST38.
(1) The drive of the pre-registration roll Rpr is stopped.
(2) The registration roll Rr is driven.
In ST38, the same process as ST38 of the first embodiment is executed, and in the case of YES, the process proceeds to ST39 '.
In ST39 ′, the following processes (1) and (2) are executed, and the process proceeds to ST40.
(1) The driven pre-registration roll Rpr2 is moved to the pre-registration separation position.
(2) Stop driving the registration roll Rr.
In ST40 to ST47, processing similar to ST40 to ST47 of the first embodiment is executed, the downstream end alignment processing of the second embodiment is terminated, and the process returns to the skew correction processing of the second embodiment.

(Operation of Example 2)
FIG. 20 is an explanatory diagram when the recording sheet is conveyed by the feeding member. FIG. 20A is an explanatory diagram when the recording sheet is conveyed by the cross roll, and is an explanatory diagram before the recording sheet is conveyed. FIG. 20C is an explanatory diagram when the recording sheet is conveyed, FIG. 20C is an explanatory diagram subsequent to FIG. 20B, an explanatory diagram when the skew of the recording sheet is corrected, and FIG. 20D is an explanatory diagram when the recording sheet is moved by the pre-registration roll. FIG. 20E is an explanatory diagram before the recording sheet is conveyed in the explanatory diagram when conveyed, FIG. 20E is an explanatory diagram subsequent to FIG. 20D, an explanatory diagram when the recording sheet is conveyed, and FIG. 20F is an explanatory diagram subsequent to FIG. FIG. 6 is an explanatory diagram when the skew of the recording sheet is corrected.
In the image forming apparatus U according to the second embodiment having the above-described configuration, the skew correction process according to the second embodiment is executed.

That is, when it is determined that the recording sheet S is fed by SEF, the side edge aligning process of the second embodiment is executed, and in FIG. 20A, the pre-registration roll Rpr moves to the pre-registration separation position, and the cross-trol Rc. 'Moves to the cross contact position. Then, the recording sheet S conveyed through the sheet conveying path SH2 by the cross-trol Rc ′ of the feeding member Rc ′ + Rpr is sent to the side guide 18 side as shown in FIGS. 20B and 20C, and recording is performed. The side edge of the sheet S comes into contact with the side guide 18 and the skew is corrected.
When it is determined that the recording sheet S is fed by LEF, the downstream end alignment process of the second embodiment is executed, and in FIG. 20D, the pre-registration roll Rpr moves to the pre-registration contact position, and the cross-trol Rc. ′ Moves to the cross spaced position. Then, the recording sheet S conveyed through the sheet conveying path SH2 by the pre-registration roll Rpr of the feeding member Rc ′ + Rpr is sent to the registration roll Rr side as shown in FIGS. 20E and 20F, and the recording sheet S The downstream end of this is abutted against the registration roll Rr to form a loop and the skew is corrected.

  Therefore, also in the image forming apparatus U of the second embodiment, as in the first embodiment, the feeding member Rc ′ + Rpr does not use the short side of the recording sheet S but the long side with higher correction accuracy than the short side. 18 or the registration roll Rr, the skew is corrected, and the skew of the recording sheet S is accurately corrected.

Next, the third embodiment of the present invention will be described. In the description of the third embodiment, the same reference numerals are given to the components corresponding to the components of the first and second embodiments, and the detailed description thereof will be given. Is omitted.
This embodiment is different from the second embodiment in the following points, but is configured in the same manner as the second embodiment in other points.

(Description of sheet conveyance path SH2)
FIG. 21 is an explanatory diagram of the sheet conveyance path of the third embodiment, and corresponds to FIG. 14 of the second embodiment.
FIG. 22 is an explanatory diagram of the feeding member of the third embodiment and corresponds to FIG. 15A of the second embodiment.
21 and 22, in the image forming apparatus U according to the third embodiment, the pre-registration roll Rpr according to the second embodiment is omitted. The image forming apparatus U according to the third embodiment has a cross trol Rc ″ as an example of an oblique feeding member instead of the cross trol Rc ′ as an example of a second transport member according to the second embodiment.
The cross trol Rc ″ is configured in the same manner as the cross trol Rc ′ in the second embodiment. However, the cross trol Rc ″ is integrally supported by a cross holder 51 as an example of a support member instead of the image forming apparatus main body U3. Therefore, the cross roll Rc ″ according to the third exemplary embodiment is configured so that the recording sheet S is fed in a direction inclined toward the side guide 18 with respect to the feeding direction of the recording sheet S toward the registration roll Rr. The cloth holder 51 is integrally supported.

In FIG. 22, the cloth holder 51 has a lower plate 52 as an example of a lower plate-like member. The lower plate 52 is supported by a guide 53 as an example of a guide member provided in the image forming apparatus main body U3 so as to be movable in the front-rear direction. A rack gear 54 as an example of a member to be transmitted is formed on the lower surface of the lower plate 52. A driving force is transmitted to the rack gear 54 from a holder driving motor 56 as an example of a driving source of the support member.
On the upper surface of the lower plate 52, a drive cross-trol Rc1 in the cross-trol Rc ″ and a feed drive motor 23 are integrally supported. Are integrally supported by a connecting plate 57 as an example of a connecting member extending upward.

On the upper end of the connecting plate 57, an upper plate 58 as an example of an upper plate member extending toward the front is integrally supported. On the lower surface of the upper plate 58, a driven cross roll Rc2 in the cross roll Rc ″ and a nip pressure adjusting member 29 are integrally supported.
The lower plate 52, the rack gear 54, the connecting plate 57, and the upper plate 58 constitute a cross holder 51 of the third embodiment. As the holder drive motor 56 rotates forward and backward, the cross holder 51 that integrally supports the cross roll Rc ″ moves back and forth along the guide 53.
The cross roll Rc ″ and the cross holder 51 constitute a feed member Rc ″ +51 of the third embodiment.

  In FIG. 21, an upstream cross sensor 59 that detects the passage of the recording sheet S is disposed on the upstream side of the cross trawl Rc in the sheet conveyance path SH2 of the third embodiment. In FIG. 22, a holder sensor 61 that detects a home position as an example of an initial position of the cross holder 51 is disposed on the upper rear side of the cross holder 51.

(Description of Controller C of Example 3)
FIG. 23 is a block diagram illustrating the functions of the control unit of the image forming apparatus according to the third embodiment, and corresponds to FIG. 16 according to the second embodiment.
FIG. 24 is a block diagram illustrating the functions of the control unit of the image forming apparatus according to the third embodiment, and is an explanatory diagram subsequent to FIG.
(Signal input element connected to controller C)
In FIG. 23 and FIG. 24, the controller C of the third embodiment receives signals from signal input elements such as the upstream cross sensor 59 and the holder sensor 61 in addition to the signal input elements UI and 13 to 17 of the second embodiment. ing.
59: Upstream cross sensor The upstream cross sensor 59 detects the presence or absence of the recording sheet S, and detects whether or not the recording sheet S has passed the detection position on the upstream side of the cross troll Rc.
61: Holder sensor The holder sensor 61 detects whether or not the cloth holder 51 has moved to the home position.

(Control element connected to controller C)
In the controller C of the third embodiment, the solenoid drive circuit D7 and the pre-registration drive circuit D8 of the second embodiment are omitted. The controller C of the third embodiment is connected to the holder drive circuit D9 in addition to the control elements D to D5 and E of the second embodiment, and outputs their operation control signals.
D9: Holder Drive Circuit A holder drive circuit D9 as an example of a drive circuit for the cross holder 51 drives the holder drive motor 56 to move the cross holder 51 in the front-rear direction.

(Function of the controller C)
The controller C of the third embodiment has a sheet passage determining means C6 'and a feeding member control means C10' of the third embodiment instead of the sheet passage determining means C6 and the feeding member control means C10 of the second embodiment. Yes.
C6 ′: Sheet Passing Discriminating Unit The sheet passing discriminating unit C6 ′ according to the third exemplary embodiment is recorded on the sheet transport path SH2 based on the detection result of the upstream clost sensor 59 in addition to the detection result of the sensors 16 and 17. The passage of the sheet S is determined.
In addition to the passage determination of the recording sheet S of the second embodiment, the sheet passage determination means C6 ′ of the third embodiment determines whether or not the front end of the recording sheet S has passed the upstream clost sensor 16 and whether the rear end of the recording sheet S is It is determined whether the upstream registration sensor 16 has been passed.

C10 ': Feed member control means The feed member control means C10' has a cross roll control means C10A 'and a cross holder control means C10C instead of the cross roll control means C10A and the pre-registration roll control means C10B of the second embodiment. Then, the driving and movement of the feeding member Rc ″ +51 are controlled.
The feeding member control means C10 'of Embodiment 3 stops the cloth holder 51 and stops the recording sheet S on the cloth roll Rc "when the feeding judgment means C5 determines that the recording sheet S satisfies the feeding condition. To send.
Further, the feeding member control means C10 ′ according to the third embodiment is configured to move the cloth holder 51 away from the side guide 18 when the feeding judgment means C5 determines that the recording sheet S does not satisfy the feeding condition, that is, The recording sheet S is brought into contact with the registration roll Rr by causing the crossing roll Rc ″ to feed the recording sheet S while moving forward.

C10A ': Cross-trolling control means A cross-trolling control means C10A' as an example of an oblique feeding member control means has a clost contact / separation control means C10A1 'and a crushed drive control means C10A2'. Control drive and contact separation.
The crossed contact / separation control means C10A1 'of the third embodiment performs the same processing as the crossed contact / separation control means C8B of the first embodiment, and the crossed drive control means C10A2' of the third embodiment performs the crossed drive of the first embodiment. Since the same processing as that of the control unit C8C is performed, detailed description of the crossed contact / separation control unit C10A1 ′ and the crossed drive control unit C10A2 ′ is omitted.

C10C: Crossed Holder Control Unit A crossed holder control unit C10C as an example of a support member control unit has a crossed home position determination unit C10C1, and drives the holder driving motor 56 via the holder driving circuit D9, thereby The holder 51 is moved in the medium width direction.
When the recording sheet S is fed, the cloth holder holder C10C according to the third embodiment moves the cloth holder 51 to the home position and stops it.
The crossed holder control unit C10C according to the third exemplary embodiment is configured such that when the feeding determination unit C5 determines that the recording sheet S does not satisfy the feeding condition, the downstream end of the recording sheet S is the upstream crossing sensor 59. When the crossed holder 51 is determined to have passed through the detection area, the cloth holder 51 moved to the home position is moved forward at a preset movement speed vh. Then, when it is determined that the loop formation time t1 has elapsed, the cloth holder control unit C10C according to the third embodiment stops the movement of the cloth holder 51 forward, and the upstream end of the recording sheet S is the upstream registration sensor 17. When the crossed holder 51 is determined to have passed, the crossed holder 51 is moved to the home position.

FIG. 25 is an explanatory diagram of the cross-trolling conveyance speed and the crossing holder moving speed, FIG. 25A is an explanatory diagram of the recording sheet conveyance speed by the cross-trolling, and FIG. 25B is a recording sheet by the cross-trolling when the crossing holder moves. It is explanatory drawing of the conveyance speed of.
The moving speed vh is set based on the medium width direction component v1 of the transport speed v of the cross-trol Rc ″.
That is, in FIG. 25A, the crossing of the third embodiment is compared with the crossing roll Rc ″ of the third embodiment that conveys the recording sheet S at the conveyance speed v in the direction inclined toward the side guide 18 with respect to the sheet conveyance path SH2. The moving speed vh of the holder 51 moves the cross-trol Rc ″ in a direction away from the side guide 18, that is, in a direction to cancel the medium width direction component v 1 of the transport speed v.
The transport speed v and transport direction of the cross-trol Rc ″ are measured and set in advance through experiments or the like.
C10C1: Holder home position determination means The holder home position determination means C10C1 as an example of the initial position determination means of the support member determines whether or not the crossed holder 51 has moved to the home position based on the detection result of the crossed sensor 61. Determine.

(Explanation of flowchart of Example 3)
Next, a processing flow of the image forming apparatus U according to the third exemplary embodiment of the present invention will be described with reference to a flowchart.
(Description of Flowchart of Skew Correction Processing in Embodiment 3)
In the skew correction processing of the third embodiment, in ST3 and ST4, instead of the side edge alignment processing of the first embodiment or the downstream edge alignment processing of the first embodiment, the side edge alignment processing of the third embodiment or the downstream end of the third embodiment. Since the same processing as the skew correction processing of the first embodiment is executed except that the alignment processing is called, detailed description thereof is omitted.

(Description of Flowchart of Side Edge Alignment Processing in Embodiment 3)
FIG. 26 is a flowchart of the side edge alignment process according to the third embodiment of the present invention, and corresponds to FIG. 10 according to the first embodiment.
In the side edge aligning process of the third embodiment, ST11 ″ is executed in place of ST11 of the side edge process of the first embodiment. In the side edge aligning process of the third embodiment, the side of the first embodiment except for ST11 ″ Since the same processing as the end processing is executed, only ST11 ″ will be described, and descriptions of the other steps ST12 to ST23 will be omitted.
In ST11 ″ in FIG. 26, the cross holder 51 is moved to the home position, and the process proceeds to ST12.

(Description of Flowchart of Downstream Edge Alignment Processing in Embodiment 3)
FIG. 27 is a flowchart of downstream end alignment processing according to the third embodiment of the present invention, and corresponds to FIG. 11 according to the first embodiment.
FIG. 28 is a flowchart of downstream end alignment processing according to the third embodiment of the present invention, and is an explanatory diagram continued from FIG.
In the downstream end alignment process of the third embodiment, ST31 ″ and ST37 ″ are executed instead of ST31 and ST37 of the downstream end alignment process of the first embodiment. In the downstream end alignment process of the third embodiment, ST101 and ST102 are executed between ST33 and ST34 of the first embodiment, and ST103 and ST104 are executed between ST44 and ST45.
In the downstream end alignment process of the third embodiment, the same processes as the downstream end alignment process of the first embodiment are executed except for those.

27 and 28, the cross holder 51 is moved to the home position, and the process proceeds to ST32.
In ST32 and ST33, the same processing as ST32 and ST33 of the first embodiment is executed, and the process proceeds to ST101.
In ST101, it is determined whether or not the downstream end of the recording sheet S transported through the sheet transport path SH2, that is, the so-called front end, has been detected by the upstream cross sensor 59. If yes (Y), the process proceeds to ST102, and if no (N), ST101 is repeated.
In ST102, the cloth holder 51 starts to move forward at the speed v1, and proceeds to ST34.
In ST34 to ST36, the same processing as ST34 to ST36 of the first embodiment is executed. In ST36, if yes (Y), the process proceeds to ST37 ″.

In ST37 ″, the following processes (1) to (3) are executed, and the process proceeds to ST38.
(1) Stop the driving of the cross troll Rc.
(2) The registration roll Rr is driven.
(3) Stop the movement of the cloth holder 51.
In ST38 to ST44, the same process as ST38 to ST44 of the first embodiment is executed, and the process proceeds to ST103.
In ST103, it is determined whether or not the upstream registration sensor 16 has detected the upstream end of the recording sheet S conveyed along the sheet conveyance path SH2, that is, the so-called trailing end. If yes (Y), the process proceeds to ST104, and if no (N), ST103 is repeated.
In ST104, the cross holder 51 is moved to the home position, and the process proceeds to ST45.
In ST45 to ST47, the same processing as ST45 to ST47 of the first embodiment is performed, the downstream end alignment processing of the third embodiment is terminated, and the process returns to the skew correction processing of the third embodiment.

(Operation of Example 3)
FIG. 29 is an explanatory diagram when the recording sheet is conveyed by the feeding member of the third embodiment, and FIG. 29A is an explanatory diagram when the cloth holder is stationary and conveys the recording sheet, and is an explanation before the recording sheet is conveyed. 29B is an explanatory diagram subsequent to FIG. 29A and is an explanatory diagram when the recording sheet is conveyed. FIG. 29C is an explanatory diagram subsequent to FIG. 29B and an explanatory diagram when the skew of the recording sheet is corrected. FIG. FIG. 29 is an explanatory diagram when the recording sheet is conveyed while the clostable holder is moving, and is an explanatory diagram when the recording sheet passes the upstream clost sensor. FIG. 29E is an explanatory diagram subsequent to FIG. FIG. 29F is an explanatory diagram subsequent to FIG. 29E and is an explanatory diagram when the skew of the recording sheet is corrected.
In FIG. 29, in the image forming apparatus U according to the third embodiment having the above-described configuration, the skew correction process according to the third embodiment is executed.

  That is, when it is determined that the recording sheet S has been fed by SEF, the side edge aligning process of the third embodiment is executed, and the cloth holder 51 is moved to the home position as shown in FIG. 29A. The cross trol Rc ″ is moved to the contact position, and the nip pressure is adjusted to be weak. Then, as shown in FIG. 29B, the recording sheet S is moved by the cross trol Rc ″ of the feeding member Rc ″ +51. The sheet is fed in a direction inclined toward the side guide 18 with respect to the direction of feeding to the registration roll Rr, and the side edge of the recording sheet S comes into contact with the side guide 18 as shown in FIG. The

Further, when it is determined that the recording sheet S is fed by LEF, the downstream end aligning process of the third embodiment is executed, the crossed holder 51 is moved to the home position, and the crossed roll Rc ′ is moved to the contact position. The nip pressure is strongly adjusted. Then, as shown in FIG. 29D, when the downstream end of the recording sheet S is detected by the upstream cross sensor 59, the cross holder 51 moves to the front side at a moving speed vh, and the cross roll Rc supported by the cross holder 51 is provided. ″ Also moves forward.
Then, when the recording sheet S is sandwiched between the cross-trols Rc ″, the recording sheet S is moved forward at the moving speed vh and is fed at the conveying speed v in a direction inclined toward the side guide 18 with respect to the sheet conveying path SH2. When the cloth holder 51 is moved to the front side at the moving speed vh, the recording sheet S is relatively moved by the cloth roll Rc ″ along the sheet conveyance path SH2 as shown in FIG. 29E. Is sent in the medium transport direction component v2.
Then, as shown in FIG. 29F, the downstream end of the recording sheet S is abutted against the registration roll Rr by the cross-trol Rc ″ moving to the front side at the moving speed vh to form a loop, and the skew is corrected.

  Therefore, in the image forming apparatus U of the third embodiment, similarly to the first and second embodiments, the feeding member Rc ″ +51 does not use the short side of the recording sheet S, but the long side with higher correction accuracy than the short side. The skew is corrected by abutting against the side guide 18 or the registration roll Rr, and the skew of the recording sheet S is accurately corrected.

(Example of change)
As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example, A various change is made in the range of the summary of this invention described in the claim. Is possible. Modification examples (H01) to (H010) of the present invention are exemplified below.
(H01) In each of the above-described embodiments, the printer U is illustrated as an example of the image forming apparatus. However, the present invention is not limited to this, and can be applied to a copying machine, a FAX, or a multifunction machine having a plurality of functions. Further, the image forming apparatus is not limited to an electrophotographic image forming apparatus, and can be applied to an image forming apparatus of an arbitrary image forming system such as an ink jet recording system, a thermal head system, or a printing machine such as a lithograph. Further, the image forming apparatus is not limited to a multi-color developing image forming apparatus, and may be configured by a monochromatic, so-called monochrome image forming apparatus.
(H02) In each of the embodiments described above, the configuration in which three cross-trols Rc to Rc ″ are arranged in the sheet conveyance path SH2 is illustrated, but two or less or four or more cross-trols Rc to Rc ″ are arranged. Configuration is also possible.

(H03) In each of the embodiments, as an example of the feeding condition, when the sheet is fed with SEF under the condition that the side edge is longer than the downstream edge, the recording sheet S is used. In the case where the sheet is brought into contact with the side guide 18 and fed by LEF, the skew is corrected by abutting against the registration roll Rr. However, as a feeding condition, the recording sheet is longer at the side end than at the downstream end. It is not limited to the condition that it is S.
For example, if the correction accuracy of the LEF recording sheet S brought into contact with the side guide 18 is higher than the case of correcting the skew by abutting against the registration roll Rr, the recording accuracy is higher. A configuration in which the sheet S is brought into contact with the side guide 18 is also possible. That is, with respect to the type of the recording sheet S, such as the thickness and paper quality, an experiment is performed in advance, and the correction accuracy of the skew is compared between the case where the recording sheet S is brought into contact with the side guide 18 and the case where it abuts against the registration roll Rr It is also possible to set a feed condition by setting a reference table, a so-called look-up table, so that the skew is corrected at.
Further, when the length of the side edge of the recording sheet S fed by LEF is equal to or larger than a preset reference length, the recording sheet S is brought into contact with the side guide 18 and the length of the side edge is less than the reference length. In such a case, it is possible to set the feed condition so as to abut against the registration roll Rr.

(H04) In each of the above-described embodiments, the configuration of the feed member is represented by the symbols Rc, Rc ′ + Rpr, Rc ″ +51, but is not limited thereto. For example, the registration feed position and the guide feed position of the first embodiment The configuration of the feed members Rc, Rc ′ + Rpr, Rc ″ +51 in each of the embodiments is arbitrarily selected, for example, the feed member is configured by combining the cross roll Rc that can be moved to the pre-registration roll Rpr of the second embodiment. In combination, the recording sheet S can be sent to the side guide 18 or the registration roll Rr.
(H05) In each of the embodiments described above, in the downstream end alignment process, the cross-trols Rc to Rc ″ are exemplified to stop driving when the loop formation time t1 has elapsed, but the present invention is not limited to this. A configuration is also possible in which the driving of the cross rolls Rc to Rc ″ is stopped after the loop formation time t1 has elapsed and the driving of the registration roll Rr is started.
Therefore, in the case of the third embodiment, the driving of the cross troll Rc ″ is stopped and the movement of the cross holder 51 is stopped in ST37 ″ of the downstream end aligning process. For example, in ST39, the cross troll Rc ″ is stopped. A configuration in which the driving of the cross holder 51 is stopped is also possible.

(H06) In the first embodiment, each cross troll Rc is supported by the corresponding rotary tables 19 and 27, and moves between the registration feed position and the side feed position. It is not limited to. For example, a configuration is possible in which all the cross-trols Rc are supported by a single turntable and are rotated together to move between the registration feed position and the side feed position.
(H07) In the second embodiment, the configuration in which one pre-registration roll Rpr is arranged is exemplified, but the present invention is not limited to this. For example, similarly to the cross roll Rc ′, a configuration in which a plurality of pre-registration rolls Rpr are arranged along the sheet conveyance path SH2 or a configuration in which a plurality of pre-registration rolls Rpr are arranged in the medium width direction on the upstream side of the registration roll Rr is possible. It is.

(H08) In the second embodiment, the cross trol Rc ′ is configured by the nip pressure adjusting member 29 and is moved between the cross contact position and the cross separation position. However, the present invention is not limited to this. In place of the pressure adjusting member 29, the contact / separation mechanism in the pre-registration roll Rpr of Embodiment 2, that is, the link 42, the tension spring 43, and the solenoid 44 can be configured to move between the cross contact position and the cross separation position. is there. That is, the nip pressure adjusting mechanism can be omitted in the cross-trol Rc ′ of the second embodiment.
A configuration in which the pre-registration roll Rpr of the second embodiment is supported by the nip pressure adjusting member 29 instead of the configuration by the link 42, the tension spring 43, and the solenoid 44 is also possible.
(H09) In the third embodiment, a configuration using a so-called rack and pinion mechanism in which the cloth holder 51 moves via the rack gear 54 is exemplified. However, the configuration is not limited to this, and a conventionally known configuration such as a configuration using a ball screw mechanism can be used. It can be moved in a configuration.
(H010) In the third embodiment, in the side edge aligning process, it is desirable to move the crossed holder 51 to the home position and stop it, but the crossed roll Rc ″ can contact the recording sheet S, and the crossed roll Rc ″. As long as the recording sheet S sent by can contact the side guide 18, the recording sheet S can be stopped at any position in the width direction.

18 ... side end alignment member,
51. Support member,
C5: Feed discrimination means,
C8, C10, C10 '... feed member control means,
Rr: downstream end alignment member,
Rpr: first conveying member,
Rc′—second conveying member,
Rc ″: an oblique feed member,
Rc, Rc ′ + Rpr, Rc ″ +51... Feed member,
S ... medium,
SH2 ... transport path,
SU: Medium transport device,
U: Image forming apparatus,
U3a: Image forming apparatus main body.

Claims (3)

A transport path through which the medium is transported;
A downstream end aligning member that is provided in the transport path and aligns the posture of the medium when the downstream end of the medium transported in the transport path on the downstream side of the medium is abutted;
Provided in the transport path, configured to be able to contact a side end in a medium width direction that is a direction orthogonal to a medium transport direction of a medium transported through the transport path, and the side end of the medium is in contact A side end aligning member that aligns the posture of the medium,
A feed member that is arranged on the upstream side of the downstream end alignment member and that sends the medium transported through the transport path to the downstream side;
A feed discriminating means for discriminating whether or not the medium satisfies a feed condition for sending the medium transported in the transport path to the side edge aligning member side;
When it is determined by the feeding determining means that the medium satisfies the feeding condition, the feeding member is controlled to send the medium to the side edge aligning member side, and the side edge of the medium is When the medium is brought into contact with the side edge aligning member and the medium is determined that the medium does not satisfy the condition for feeding, the medium is fed to the downstream edge aligning member side by controlling the feeding member. Feed member control means for abutting the downstream end of the medium against the downstream end alignment member;
A first feed position for feeding the medium to the downstream end aligning member side, and a second feed position for sending the medium in a direction inclined toward the side end aligning member with respect to the direction of feeding the medium to the downstream end aligning member side And the feeding member provided to be movable between,
When it is determined by the feed determining means that the medium satisfies the feed condition, the feed member is moved to the second feed position, and the medium satisfies the feed condition by the feed determining means. The feed member control means for moving the feed member to the first feed position when it is determined that there is not,
A medium carrying device comprising: A transport path through which the medium is transported;
A downstream end aligning member that is provided in the transport path and aligns the posture of the medium when the downstream end of the medium transported in the transport path on the downstream side of the medium is abutted;
Provided in the transport path, configured to be able to contact a side end in a medium width direction that is a direction orthogonal to a medium transport direction of a medium transported through the transport path, and the side end of the medium is in contact A side end aligning member that aligns the posture of the medium,
A feed member that is arranged on the upstream side of the downstream end alignment member and that sends the medium transported through the transport path to the downstream side;
A feed discriminating means for discriminating whether or not the medium satisfies a feed condition for sending the medium transported in the transport path to the side edge aligning member side;
When it is determined by the feeding determining means that the medium satisfies the feeding condition, the feeding member is controlled to send the medium to the side edge aligning member side, and the side edge of the medium is When the medium is brought into contact with the side edge aligning member and the medium is determined that the medium does not satisfy the condition for feeding, the medium is fed to the downstream edge aligning member side by controlling the feeding member. Feed member control means for abutting the downstream end of the medium against the downstream end alignment member;
The oblique feeding member that feeds the medium in a direction inclined toward the side edge aligning member with respect to the direction of feeding the medium toward the downstream end aligning member, and the oblique feeding member that is supported so as to be movable in the medium width direction. And a support member that supports the feed member,
When it is determined by the feed determining means that the medium satisfies the feed condition, the support member is stopped and the medium is sent to the oblique feed member, and the medium is detected by the feed determining means. When it is determined that the feeding condition is not satisfied, the medium is sent to the oblique feeding member while moving the support member in a direction away from the side edge aligning member, whereby the medium is sent to the downstream edge aligning member. The feeding member control means to abut,
A medium carrying device comprising: The medium conveying device according to claim 1 or 2 ,
An image recording unit for recording an image on a medium conveyed by the medium conveying device;
An image forming apparatus comprising:

Images