JP2019147663A - Sheet conveying device, automatic document conveying device, image reading device and image forming device - Google Patents

Abstract

A sheet conveying device, an automatic document conveying device, an image reading device, and an image capable of suppressing a sheet from tilting in a conveying direction after adjusting a position in a width direction by sandwiching a sheet between two pairs of nipping and conveying members. A forming device is provided. A sheet conveying apparatus 300 including two pairs of nipping / conveying members (18 and 45) capable of conveying a sheet P therebetween and moving in a width direction orthogonal to the conveying direction is one sheet. P is moved in the width direction in a state where P is sandwiched between the two pairs of sandwiching and conveying members (18 and 45). After the movement in the width direction, P of the two pairs of sandwiching and conveying members (18 and 45) is used. The two nipping and conveying members (45a and 45b) forming the upstream nipping and conveying member pair 45 located on the upstream side in the conveying direction are separated from each other, and the two nipping and conveying member pairs (18 and 45) in the conveying direction are separated. The sheet P is transported by the pair of downstream-side nip transport members 18 located on the downstream side. [Selection diagram] Fig. 1

Description

  The present invention relates to a sheet conveying apparatus, an automatic document conveying apparatus, an image reading apparatus, and an image forming apparatus.

2. Description of the Related Art Conventionally, there is known a sheet conveying apparatus that includes two pairs of nipping and conveying members capable of conveying a sheet while sandwiching the sheet and moving in a width direction orthogonal to the conveying direction.
For example, in Patent Document 1, the first clamping roller and the second clamping roller are arranged in the width direction in a state where the recording medium (sheet) is clamped by the first clamping roller and the second clamping roller (two pairs of clamping conveyance members). And correcting the positional deviation in the width direction of the recording medium.

  However, as in Patent Document 1, in the configuration in which the sheet is sandwiched between two pairs of sandwiching conveyance members and moved in the width direction, the sheet is conveyed with respect to the conveyance direction during conveyance of the sheet after correcting the positional deviation. Sometimes tilted.

  In order to solve the above-described problem, the present invention provides a sheet conveying apparatus including two pairs of nipping and conveying members capable of conveying a sheet while sandwiching the sheet and moving in a width direction orthogonal to the conveying direction. The sheet is moved in the width direction in a state where the sheet is sandwiched between two pairs of the sandwiching conveyance member pairs, and after the movement in the width direction, the sheet of the two pairs of sandwiching conveyance member pairs in the conveyance direction is moved. A pair of downstream holding and conveying members that form an upstream holding and conveying member pair positioned on the upstream side are separated from each other and are located downstream of the two pairs of holding and conveying member pairs in the conveying direction. The sheet is conveyed.

  According to the present invention, there is an excellent effect that it is possible to prevent the sheet from being inclined with respect to the conveyance direction after adjusting the position in the width direction by sandwiching the sheet between the two pairs of nipping and conveying members.

Explanatory drawing of operation | movement after the front-end | tip of a sheet | seat passes the detection position of the width direction position detection sensor in the pre-transfer conveyance part of this embodiment. 1 is a schematic configuration diagram of a printer according to an embodiment. Explanatory explanatory drawing of the pre-transfer conveyance part of this embodiment. The block diagram which shows the relationship between the roller pair arrange | positioned in the conveyance part before transfer, a sensor, and a control part. FIG. 5 is an explanatory diagram of a pre-transfer conveyance unit of Reference Configuration Example 1. 4 is an explanatory diagram schematically showing a state in which the sheet is shifted by a pair of registration rollers in Reference Configuration Example 1. FIG. Explanatory drawing of the pre-transfer conveyance part of the reference structural example 2. FIG. FIG. 6 is an explanatory diagram schematically illustrating a state in which a sheet is shifted by a registration roller pair and a sheet feeding unit exit roller pair in Reference Configuration Example 2. 9 is a flowchart of a shift operation of a pre-transfer conveyance unit according to the present embodiment. The top view of the width direction position detection sensor vicinity. Explanatory drawing of the relay roller pair contact / separation mechanism which contacts / separates a relay roller pair. Explanatory drawing of the paper feed part exit drive mechanism of embodiment. Explanatory drawing of the paper feed part exit drive mechanism of a modification. Explanatory drawing of the sheet feeding part exit roller contact / separation mechanism of the modification. FIG. 6 is a schematic configuration diagram of a copying machine including an automatic document feeder according to a second embodiment. FIG. 5 is a schematic configuration diagram of an image reading apparatus according to a second embodiment.

  Hereinafter, an electrophotographic printer (hereinafter simply referred to as a printer) that forms an image by an electrophotographic method will be described as an image forming apparatus including a sheet conveying apparatus according to the present invention. In the present embodiment, a color laser printer will be described as an example of an image forming apparatus. However, the image forming apparatus is not limited to a color one but may be a monochrome one, and is not limited to a printer. The image forming apparatus may be used. Further, the image forming apparatus provided with the sheet conveying apparatus according to the present invention is not limited to the electrophotographic system, and may be an image forming apparatus of another system such as an ink jet system.

FIG. 2 is a schematic configuration diagram of the printer 100 according to the present embodiment.
In the printer 100, an intermediate transfer belt 16 is provided substantially at the center of the printer main body 1. Above the intermediate transfer belt 16, four image forming units 2 (Y, M, C, and Y) that perform image formation with toner of each color of yellow (Y), cyan (C), magenta (M), and black (K). K) are arranged side by side. The four image forming units 2 (Y, M, C, and K) have substantially the same configuration and operation except that the colors of the toners used are different. Therefore, in the following description, reference numerals indicating colors are omitted. The image forming unit 2 will be described.

The image forming unit 2 includes a photosensitive member 12 that is a latent image carrier facing the upper tension surface of the intermediate transfer belt 16, and a charging device 11 that is a charging unit and a latent image formation are formed around the photosensitive member 12. A laser scanning unit 10 as a means and a developing device 13 as a developing means are provided. Further, a primary transfer roller 14 facing the photoconductor 12 with the intermediate transfer belt 16 interposed therebetween is provided to form a primary transfer nip.
In addition, a secondary transfer roller 15 is provided below the intermediate transfer belt 16, and a secondary transfer counter roller 16 a that is opposed to the secondary transfer roller 15 with the intermediate transfer belt 16 interposed therebetween to form a secondary transfer nip. .

  A lower part of the printer main body 1 includes a paper feeding device 200 having first to third three-stage paper feeding trays 5. The three paper feed trays 5 of the paper feed device 200 can be pulled out from the printer main body 1, and each paper feed tray 5 accommodates paper P made of transfer paper or resin film. The sheet feeding device 200 includes a sheet feeding roller 51, a separation conveyance roller 52, and a reverse roller 53 corresponding to each of the three stages of sheet feeding trays 5.

In the paper feeding device 200, the paper P sent out by the paper feeding roller 51 is fed into a separation nip that is a contact portion between the separation conveyance roller 52 and the reverse roller 53. The separation conveyance roller 52 is driven to rotate in the counterclockwise direction in FIG. 2 by being driven by a drive motor, and applies a conveyance force toward the downstream side in the conveyance direction to the paper P.
A reverse roller 53 is in contact with the separation conveyance roller 52. The reverse roller 53 is driven by a drive motor so as to rotate in the counterclockwise direction in FIG.

  In such a configuration, the surface movement direction in the separation nip between the separation conveyance roller 52 and the reverse roller 53 is reversed, and thereby the uppermost sheet P of the bundle of sheets P is separated from the sheet P below it. In this configuration, only the uppermost sheet P can be fed.

  When the printer 100 receives image information from an input terminal such as a personal computer or the operation panel 3 and starts a printing operation, the photosensitive member 12 is driven to rotate counterclockwise in FIG. It is rotationally driven in the clockwise direction in FIG. At this time, the surface of the photoconductor 12 is uniformly charged to a predetermined polarity by the charging device 11. Next, the surface of the uniformly charged photoreceptor 12 is irradiated with laser light based on image information from the laser scanning unit 10 of each color, whereby an electrostatic latent image is formed on the photoreceptor 12. The electrostatic latent image formed on the surface of the photoconductor 12 is visualized as a toner image by the developing device 13, and the toner image is transferred to the intermediate transfer belt 16 by the primary transfer roller 14 at the primary transfer nip. . The transfer residual toner adhering to the surface of the photoconductor 12 after the toner image is transferred is removed by the photoconductor cleaning device.

  At the time of color image formation, the above-described image forming operation is performed in all the image forming units 2, whereby the yellow toner image, cyan toner image, magenta toner image, and black toner image respectively formed on each photoconductor 12 are intermediate. The images are sequentially transferred onto the transfer belt 16.

On the other hand, the paper P is fed from the paper feeding device 200. When the user selects a paper feed tray 5 to be used from the three stages of paper feed trays 5 using an input terminal such as a personal computer or the operation panel 3, the paper P stored in the selected paper feed tray 5 is stored. Paper is fed.
A broken line indicated by a symbol “19” in FIG. 2 indicates a conveyance path through which the paper P passes through the printer 100.

The fed paper P is fed toward the registration roller pair 18 and the leading edge of the paper P is abutted against the stopped registration roller pair 18. As shown in FIG. 2, a registration sensor 21 is disposed in the vicinity of the upstream side of the registration roller pair 18.
As a result, after the position of the leading end of the sheet P in the transport direction is aligned with the inclination with respect to the transport direction, the registration roller pair 18 moves the sheet P to the secondary transfer nip at a timing coincident with the toner image on the intermediate transfer belt 16. Send out toward. Transfer residual toner adhering to the surface of the intermediate transfer belt 16 after the toner image is transferred at the secondary transfer nip is removed by an intermediate transfer belt cleaning device.

The paper P on which the unfixed toner image is transferred at the secondary transfer nip is sent to the fixing device 17, and after the unfixed toner image is fixed on the paper P, it is discharged to the paper discharge tray 4 in the case of single-sided printing. The
In the case of double-sided printing, the paper P on which an image is formed on the first side is conveyed to the double-sided path by switching the conveyance path by the branching claw 40. The sheet P sent to the reversing roller pair 41 by the branching claw 40 is conveyed to the double-sided roller pair 42 by forward and reverse rotation of the reversing roller pair 41. At this time, the front and back with respect to the transport direction of the paper P are reversed from those during the image formation on the first surface. Then, after the sheet P is conveyed to the relay roller pair 43 and the registration roller pair 18, an image is also formed on the second surface by the same process as described above, and then discharged to the discharge tray 4.

  As an option, the user can connect a finisher capable of stapling and folding to the printer body 1 in place of the paper feed bank capable of feeding a large amount of paper P and the paper discharge tray 4.

  The printer 100 includes a pair of paper feed unit exit rollers 45 as a pair of transport rollers at the downstream end in the transport direction of the paper transport path 19 in the paper feed device 200.

FIG. 3 is an enlarged explanatory view of the pre-transfer conveyance unit 300 that forms the paper conveyance path 19 on the upstream side in the conveyance direction of the paper P from the secondary transfer nip in the printer 100 shown in FIG.
The pre-transfer conveyance unit 300 includes a width direction position detection sensor 46 on the downstream side in the conveyance direction in the vicinity of the registration roller pair 18, and a rear end detection sensor 47 on the upstream side in the conveyance direction in the vicinity of the paper feed unit outlet roller pair 45. .
The width direction position detection sensor 46 is a sensor that can detect the arrival of the paper P at the detection position and the position of the reached paper P in the width direction, and the trailing edge detection sensor 47 sets the detection position after the paper P. It is a sensor that can detect whether or not the end has been passed.
A relay roller pair 43 is disposed on the sheet conveyance path 19 between the sheet feeding unit exit roller pair 45 and the registration roller pair 18.

FIG. 4 is a block diagram illustrating a relationship between a roller pair and a sensor arranged in the pre-transfer conveyance unit 300 and the control unit 50 of the printer 100.
The relay roller pair 43 can contact and separate two rollers forming the roller pair. The printer 100 includes a relay roller pair drive motor 430 that inputs drive to the relay roller pair 43, and a relay roller pair contact / separation drive source 431 that is a power source for the operation of contacting and separating the two rollers of the relay roller pair 43. .

  The registration roller pair 18 is a pair of shift rollers that shifts the position in the width direction of the paper P by moving in the width direction perpendicular to the transport direction of the paper P with the paper P interposed therebetween. Also, the paper feed unit outlet roller pair 45 moves in the width direction orthogonal to the conveyance direction of the paper P while holding the paper P together with the registration roller pair 18, thereby supporting the shift operation of the registration roller pair 18. A pair of shift rollers. In addition, the registration roller pair 18 and the sheet feeding unit exit roller pair 45 can be contacted and separated by two rollers forming the roller pair.

The printer 100 includes a registration roller pair drive motor 180 that inputs driving to the registration roller pair 18 and a registration roller pair contact / separation motor 181 that is a power source for the operation of contacting and separating the two rollers of the registration roller pair 18. Further, a registration roller pair shift motor 182 serving as a power source for a shift operation for moving the registration roller pair 18 in the width direction is provided.
Further, the printer 100 serves as a power source for the operation of contacting and separating the two rollers of the paper feed unit exit roller pair drive motor 450 that inputs driving to the paper feed unit exit roller pair 45 and the paper feed unit exit roller pair 45. A sheet feeding unit exit roller facing / separating motor 451. Further, a paper feed unit exit roller pair shift motor 452 is provided as a power source for a shift operation for moving the paper feed unit exit roller pair 45 in the width direction.

  The leading edge of the paper P conveyed from the paper feed tray 5 passes through the paper feed unit outlet roller pair 45 and the relay roller pair 43 in this order, and reaches the registration roller pair 18. When the conveyance timing is adjusted by the registration roller pair 18 and the conveyance toward the secondary transfer nip is resumed, the position of the sheet P in the width direction (main scanning direction) is detected by the width direction position detection sensor 46. Is detected, and the control unit 50 calculates the correction amount in the width direction of the paper P. Thereby, the correction amount based on the position of the sheet P immediately before the shift operation can be calculated, and the position of the sheet P can be corrected appropriately.

The positional deviation in the width direction of the paper P is likely to occur when the user sets the paper P in the paper feed tray 5. As a configuration for suppressing the positional deviation in the width direction, an image is provided on the assumption that a side fence is provided on the paper feed tray 5 and the user arranges the side fence with high accuracy and sets the paper P with high accuracy on the side fence. Some guarantee quality.
If the configuration is such that the shift operation is performed and the positional deviation in the width direction of the paper P is corrected as in the printer 100 of the present embodiment, the paper P required by the user when the paper P is set in the paper feed tray 5. The accuracy of the set can be relaxed.

FIG. 1 shows a case where a sheet P longer than the distance of the sheet conveyance path 19 from the sheet feeding unit exit roller pair 45 to the registration roller pair 18 is conveyed to the pre-transfer conveyance unit 300 of the present embodiment, and the leading edge of the sheet P FIG. 6 is an explanatory diagram after passing through the detection position of the width direction position detection sensor 46.
FIG. 1A is an explanatory diagram immediately after the leading edge of the paper P passes the detection position of the width direction position detection sensor 46.

  When the leading edge of the paper P passes the detection position of the width direction position detection sensor 46, the relay roller contact / separation drive source 431 is driven so that the relay outer roller 43b is moved in the direction of the arrow “A1” in FIG. The relay inner roller 43a and the relay outer roller 43b are moved away from each other. Accordingly, when the shift operation is performed using the registration roller pair 18, it is possible to prevent the relay roller pair 43 positioned upstream from the registration roller pair 18 from interfering with the shift of the paper P.

After separating the relay inner roller 43a and the relay outer roller 43b from each other, the control unit 50 drives the registration roller pair shift motor 182 and the sheet feeding unit outlet roller pair shift motor 452 to register the registration roller pair 18 and the sheet feeding unit. The exit roller pair 45 is shifted in synchronization. At this time, in a state where the sheet P is sandwiched between the registration roller pair 18 and the paper feed unit exit roller pair 45, the registration roller pair 18 and the paper feed unit exit roller pair 45 are moved in the width direction to perform a shift operation.
In the present embodiment, when the paper P is moved in the width direction by the calculated correction amount in the width direction of the paper P and the shift operation is completed, the paper feed unit outlet roller contact / separation motor 451 is driven. As a result, as shown in FIG. 1C, the sheet feeding unit outlet outer roller 45b is moved in the direction away from the sheet feeding unit outlet inner roller 45a (the direction of the arrow “A2” in FIG. 1C). The paper portion outlet inner roller 45a and the paper feeding portion outlet outer roller 45b are separated from each other.

  As described above, in this embodiment, when the shift operation is completed, as illustrated in FIG. 1C, the sheet feeding unit outlet roller pair 45 is separated and the sheet P is transported only by the registration roller pair 18. When the paper feed unit exit roller pair 45 is separated, the paper feed unit exit roller pair shift motor 452 is driven, and the position in the width direction of the paper feed unit exit roller pair 45 is the initial position before the shift operation described above. Return to position. When the position in the width direction of the sheet feed unit outlet roller pair 45 becomes the initial position and the rear end of the sheet P passes the position of the sheet feed unit exit roller pair 45, the sheet feed unit exit roller pair contact / separation motor 451 is driven. Then, the two rollers of the paper feed unit outlet roller pair 45 are brought into contact with each other.

  After the paper P is started to be conveyed only by the registration roller pair 18, when the paper P is nipped by the secondary transfer nip, the registration roller contact / separation motor 181 is driven. Accordingly, the registration upper roller 18a is moved away from the registration lower roller 18b, the registration upper roller 18a and the registration lower roller 18b are separated from each other, and the sheet is moved by the surface moving body (16, 15) that forms the secondary transfer nip. P is transported. When the registration roller pair 18 is separated, the registration roller pair shift motor 182 is driven to return the position of the registration roller pair 18 in the width direction to the initial position that is the position before the shift operation described above. When the position in the width direction of the registration roller pair 18 becomes the initial position and the trailing edge of the paper P passes the position of the registration roller pair 18, the registration roller pair contact / separation motor 181 is driven to Touch two rollers.

When the trailing edge of the paper P passes the position of the relay roller pair 43, the relay roller pair contact / separation drive source 431 is driven to bring the two rollers of the relay roller pair 43 into contact with each other.
The pair of paper feed unit exit rollers 45 returns to the initial position, and the two rollers come into contact with each other, so that the rear end of the previous paper P is before the positions of the relay roller pair 43 and the registration roller pair 18. However, it is possible to receive the next sheet P.

  Here, the printer 100 of the present embodiment is a reference configuration example in which the control of the paper feed unit outlet roller pair 45 is different, and is longer than the distance of the paper transport path 19 from the paper feed unit outlet roller pair 45 to the registration roller pair 18. The operation of each unit when the paper P is conveyed will be described.

[Reference configuration example 1]
FIG. 5 is an explanatory diagram of the pre-transfer conveyance unit 300 of the first reference configuration example (reference configuration example 1). FIG. 5 shows a case where the paper P is transported longer than the distance of the paper transport path 19 from the paper feed unit exit roller pair 45 to the registration roller pair 18, and the leading end of the paper P is the width direction position detection sensor 46. It is explanatory drawing which shows operation | movement of each roller pair after passing a detection position.
The reference configuration example 1 does not include the sheet feeding unit exit roller pair shift motor 452 and does not have a function of shifting the sheet feeding unit exit roller pair 45.
Also in the reference configuration example 1, when the conveyance timing is adjusted by the registration roller pair 18 and conveyance toward the secondary transfer nip is resumed, the sheet P is detected by the width direction position detection sensor 46 in the width direction (main scanning direction). ) Is detected. Then, the control unit 50 calculates the correction amount in the width direction of the paper P.

  FIG. 5A is an explanatory diagram immediately after the leading edge of the paper P has passed the detection position of the width direction position detection sensor 46. In the reference configuration example 1, when the leading edge of the paper P passes the detection position of the width direction position detection sensor 46, the relay roller contact / separation drive source 431 and the paper feed unit exit roller contact / separation motor 451 are driven. By driving the relay roller contact / separation drive source 431, the relay outer roller 43b is moved in the direction of the arrow “A1” in FIG. 5B, and the relay inner roller 43a and the relay outer roller 43b are separated from each other. Further, by driving the paper feed unit exit roller contact / separation motor 451, the paper feed unit exit outer roller 45b is moved in the direction of the arrow “A2” in FIG. The paper feed unit outlet outer roller 45b is separated.

  When the relay roller pair 43 and the sheet feeding unit exit roller pair 45 are separated from each other, only the registration roller pair 18 is moved in the width direction by the calculated correction amount, and the position of the paper P in the width direction is aligned to make the paper P The correction of the transport position is completed. After separating the relay roller pair 43 and the sheet feeding unit outlet roller pair 45, the sheet P is formed only by the registration roller pair 18 until the sheet P is nipped by the secondary transfer nip as shown in FIG. Transport.

  Thereafter, when the sheet P is nipped by the secondary transfer nip, the registration roller contact / separation motor 181 is driven. Accordingly, the registration upper roller 18a is moved away from the registration lower roller 18b, the registration upper roller 18a and the registration lower roller 18b are separated from each other, and the sheet is moved by the surface moving body (16, 15) that forms the secondary transfer nip. P is transported. When the registration roller pair 18 is separated, the registration roller pair shift motor 182 is driven to return the position of the registration roller pair 18 in the width direction to the initial position that is the position before the shift operation described above. When the position in the width direction of the registration roller pair 18 becomes the initial position and the trailing edge of the paper P passes the position of the registration roller pair 18, the registration roller pair contact / separation motor 181 is driven to Touch two rollers. When the registration roller pair 18 returns to the initial position and the two rollers are in contact with each other, the next sheet P can be fed.

  In the reference configuration example 1, when the shift operation by the registration roller pair 18 is performed, if the rear end of the sheet P to be shifted is on the upstream side of the position of the relay roller pair 43, the following control is performed. That is, when the rear end of the sheet P does not pass through the position of the roller pair when the shift operation is performed by the roller pair upstream of the registration roller pair 18, the two rollers forming the roller pair are separated from each other. It is the composition which makes it. That is, when the rear end of the sheet P to be shifted is on the upstream side of the position of the relay roller pair 43 during the shift operation, the two rollers of the relay roller pair 43 are separated. Further, when shifting, if the trailing edge of the sheet P to be shifted is upstream of the paper feed unit outlet roller pair 45 further upstream than the relay roller pair 43, the two of the paper feed unit outlet roller pair 45 The rollers are also separated.

In the pre-transfer conveyance unit 300 of Reference Configuration Example 1, at the stage of performing the shift operation for moving the registration roller pair 18 in the width direction, the roller pair that holds the paper P is the registration roller pair 18 regardless of the length of the paper P. It becomes only.
FIG. 6 shows a first configuration example in which the sheet P guided by the pre-transfer conveyance guide 55 that is a conveyance path forming member that forms the sheet conveyance path 19 of the pre-transfer conveyance unit 300 is shifted by the registration roller pair 18. It is explanatory drawing which showed typically. An arrow “B” in FIG. 6 indicates the conveyance direction of the paper P.

When the shift operation is performed, the registration roller pair 18 applies a conveying force in the direction of the arrow “B” in FIG. 6 to the paper P, and the width as shown by the arrow “S” in FIG. Move in the direction. As a result, a force that moves in the width direction together with the registration roller pair 18 acts on the paper P as indicated by an arrow “F1” in FIG. On the other hand, since the paper P guided by the pre-transfer conveyance guide 55 is in contact with the pre-transfer conveyance guide 55, when the paper P tries to move in the width direction, it is shown in FIG. The frictional force shown by the arrow “F2” of FIG.
The force in the shift direction by the registration roller pair 18 acts only in the vicinity of the leading end in the conveyance direction of the paper P, and the frictional force with the pre-transfer conveyance guide 55 is applied to a portion in contact with the pre-transfer conveyance guide 55 in the entire conveyance direction of the paper P. Works. For this reason, the rotational moment shown by the arrow “M” in FIG. 6A acts on the paper P, and when the shift operation is completed, the paper P may be skewed as shown in FIG. 6B.

  Since the skew of the paper P is corrected when the leading edge of the paper P hits the registration roller pair 18, the skew generated when the paper P is conveyed while being sandwiched between the registration roller pair 18 is not corrected. P is conveyed to the secondary transfer nip with skew. When the toner image is transferred to the skewed paper P at the secondary transfer nip, there is a possibility that an image defect in which the image is inclined with respect to the paper P may occur.

[Reference configuration example 2]
Next, a second reference configuration example (reference configuration example 2) that can suppress the occurrence of skew in the shift operation will be described.
FIG. 7 is an explanatory diagram of the pre-transfer conveyance unit 300 of Reference Configuration Example 2. FIG. 7 shows a case where the paper P longer than the distance of the paper transport path 19 from the paper feed unit exit roller pair 45 to the registration roller pair 18 is transported, and the front end of the paper P is the width direction position detection sensor 46. It is explanatory drawing which shows operation | movement of each roller after passing a detection position.

  Unlike the reference configuration example 1, the reference configuration example 2 includes a paper feed unit exit roller pair shift motor 452, and the paper feed unit exit roller pair 45 positioned upstream of the registration roller pair 18 that is a shift roller pair It is the structure which functions as a shift roller pair. The configuration in which the paper feed unit exit roller pair 45 functions as an auxiliary shift roller pair is the same as that of the pre-transfer conveyance unit 300 of the above-described embodiment. However, the reference configuration example 2 is different from the pre-transfer conveyance unit 300 of the embodiment in that the sheet P is conveyed by the paper feed unit outlet roller pair 45 and the registration roller pair 18 even after the shift operation is completed.

FIG. 7A is an explanatory diagram immediately after the leading edge of the paper P passes the detection position of the width direction position detection sensor 46.
When the leading edge of the paper P passes the detection position of the width direction position detection sensor 46, the relay roller contact / separation drive source 431 is driven, so that the relay outer roller 43b is moved in the direction of the arrow “A1” in FIG. The relay inner roller 43a and the relay outer roller 43b are moved away from each other. Accordingly, when the shift operation is performed using the registration roller pair 18, it is possible to prevent the relay roller pair 43 positioned upstream from the registration roller pair 18 from interfering with the shift of the paper P.

After separating the relay inner roller 43a and the relay outer roller 43b from each other, the control unit 50 drives the registration roller pair shift motor 182 and the sheet feeding unit outlet roller pair shift motor 452 to register the registration roller pair 18 and the sheet feeding unit. The exit roller pair 45 is shifted in synchronization.
In the reference configuration example 2, when the paper P is moved in the width direction by the calculated correction amount in the width direction of the paper P and the shift operation is completed, as shown in FIG. The paper P is transported while the paper P is sandwiched between the paper part exit roller pair 45.

In the pre-transfer conveyance unit 300 of Reference Configuration Example 2, at the stage of performing the shift operation for moving the registration roller pair 18 in the width direction, the roller pair that holds the paper P when the paper P is long is fed with the registration roller pair 18. Two pairs of rollers, a pair of paper exit rollers 45, are provided.
FIG. 8 shows a second configuration example, in which a sheet P guided by a pre-transfer conveyance guide 55 which is a conveyance path forming member that forms the sheet conveyance path 19 of the pre-transfer conveyance unit 300 is a registration roller pair 18 and a sheet feeding unit. It is explanatory drawing which showed the state shifted by the exit roller pair 45 typically. As in FIG. 6, the arrow “B” in FIG. 8 indicates the conveyance direction of the paper P.

When the shift operation is performed, the registration roller pair 18 applies a conveying force in the direction of the arrow “B” in FIG. 8 to the paper P, and has a width as indicated by the arrow “S1” in FIG. Move in the direction. As a result, as indicated by the arrow “F1” in FIG. 8, a force that moves in the width direction along with the registration roller pair 18 acts on the paper P. Further, the pair of paper feed unit exit rollers 45 applies a conveying force in the direction of the arrow “B” in FIG. 8 to the paper P, as shown by the arrow “S2” in FIG. Move to. As a result, as indicated by an arrow “F3” in FIG. 8, a force that moves in the width direction is applied to the paper P together with the paper feed unit outlet roller pair 45.
On the other hand, since the paper P guided by the pre-transfer conveyance guide 55 is in contact with the pre-transfer conveyance guide 55, when the paper P tries to move in the width direction, the pre-transfer conveyance guide is the same as in Reference Configuration Example 1. A frictional force as shown by an arrow “F2” in FIG.

  In the reference configuration example 2, the frictional force with the pre-transfer conveyance guide 55 acts on the portion in contact with the pre-transfer conveyance guide 55 in the entire conveyance direction of the paper P, as in the reference configuration example 1. However, unlike the reference configuration example 1, the force in the direction of shifting the paper P acts on the vicinity of the front end and the rear end in the transport direction of the paper P by the registration roller pair 18 and the paper feed unit outlet roller pair 45. . For this reason, it can suppress that a rotational moment acts with respect to the paper P, and can suppress that a skew arises by shift operation.

However, in the pre-transfer conveyance unit 300 of the reference configuration example 2, the sheet P is shifted by the registration roller pair 18 and the sheet feeding unit outlet roller pair 45 to adjust the position in the width direction of the sheet P. The paper P is conveyed by the registration roller pair 18 and the paper feed unit outlet roller pair 45.
In general, a roller pair that conveys a sheet of paper P or the like has a rotation axis of the roller that is inclined with respect to the conveyance direction due to component errors or assembly errors, or abutment between two rollers that form a roller pair. Pressure varies in the axial direction. These affect the passing sheet as a skew component of each roller pair.
In the reference configuration example 2, since the paper P is transported by the registration roller pair 18 and the paper feed unit outlet roller pair 45 after the shift is finished, the transported paper P is the skew component of the two roller pairs. In some cases, the inclination of the paper P with respect to the transport direction is increased.

In the present embodiment, when the paper P shorter than the distance of the paper transport path 19 from the paper feed unit exit roller pair 45 to the registration roller pair 18 is transported, only the resist roller pair 18 is shifted in the width direction. On the other hand, when a sheet P longer than the distance of the sheet conveying path 19 from the sheet feeding unit outlet roller pair 45 to the registration roller pair 18 is conveyed, the sheet is transferred by the registration roller pair 18 and the sheet feeding unit outlet roller pair 45. The two pairs of rollers are moved in the width direction with P interposed therebetween, and a shift operation is performed.
Since the registration roller pair 18 and the sheet feeding unit exit roller pair 45 are used to shift the sheet P, the rotation moment acts on the sheet P as in the second reference configuration example described with reference to FIG. It is possible to suppress the occurrence of skew in the shift operation.

  Further, after the shift operation between the registration roller pair 18 and the paper feed unit exit roller pair 45 is finished, the paper feed unit exit roller pair 45 separates the rollers and transports the paper P only by the registration roller pair 18. . At this time, before the trailing edge of the sheet P passes through the position where the sheet feeding unit outlet roller pair 45 sandwiches the sheet P, the two rollers of the sheet feeding unit outlet roller pair 45 are separated from each other. Thereby, it is possible to suppress the paper P from being affected by the skew component (the force that tilts the paper P with respect to the transport direction) of the paper feed unit outlet roller pair 45. For this reason, it can suppress that the inclination of the paper P with respect to a conveyance direction becomes large, and the improvement of the conveyance precision of the paper P can be aimed at.

  Further, by improving the conveyance accuracy, the accuracy of the position of the paper P at the secondary transfer nip for transferring the toner image to the paper P can be improved, and the positional deviation of the image when transferred to the paper P can be suppressed. The image accuracy of the image formed on P can be improved.

  The skew of the sheet P is corrected by abutting against the registration roller pair 18. However, after passing through the registration roller pair 18, the sheet is conveyed by the registration roller pair 18 and the sheet feeding unit exit roller pair 45, thereby being affected by the skew component of these roller pairs.

  As a method of correcting the influence of the skew after passing through the registration roller pair 18, there is the following method. That is, there is a method in which a test pattern for detecting the influence of skew is imaged on the paper P, this test pattern is read by a reading means, and a corrected image is formed in accordance with the skew based on the read image information.

  When such a corrected image is formed with the configuration of the reference configuration example 2, there is the following problem. That is, in the reference configuration example 2, the skew component for inclining the paper P after the shift operation is a plurality of skew components including the skew component of the registration roller pair 18 and the skew component of the paper feed unit outlet roller pair 45, and therefore the influence of the skew. It is difficult to pattern. For this reason, it is difficult to form a corrected image that is inclined in accordance with the skew of the paper P, and the inclination of the image with respect to the paper P may be deteriorated.

  On the other hand, in the printer 100 of this embodiment that transports only the registration roller pair 18 after the shift operation, the skew component that tilts the paper P after the shift operation is only the skew component that the registration roller pair 18 has. For this reason, it is easy to pattern the influence of the skew, and it becomes easy to form a corrected image that is inclined in accordance with the skew, and it is possible to improve the image quality.

FIG. 9 is a flowchart of the shift operation of the pre-transfer conveyance unit 300 according to the present embodiment.
When the leading edge of the paper P fed from the paper feed tray 5 passes the detection position of the registration sensor 21, the registration sensor 21 is turned "ON" (S1). After this “ON”, the conveyance of the paper P is temporarily stopped at the timing when the leading edge of the paper P hits the registration roller pair 18, and it is detected whether or not the length of the paper P reaches the paper feed unit outlet roller pair 45. (S2). In this embodiment, when the trailing edge detection sensor 47 detects the paper P at the timing when the conveyance of the paper P is stopped, the length of the paper P when the leading edge reaches the registration roller pair 18 is determined by the paper feeding unit. It is determined that the length reaches the exit roller pair 45 (“Yes” in S2).

  The determination of the length of the paper P is not limited to the configuration in which the length of the paper P being transported is detected based on the detection result of the sensor disposed in the paper transport path 19. The length of the paper P may be determined based on the size information of the paper P set in the paper feed tray 5 that has fed the paper P or the size information of the transported paper P input from the operation panel 3 or the like. .

  For example, a printer 100 having a plurality of paper feed trays 5 generally divides the paper feed tray 5 on which the paper P is set according to the size and orientation of the paper P. The size information in the length direction of the paper P set in each paper feed tray 5 is stored in the storage unit of the control unit 50. For this reason, the length information of the length of the paper P set in the paper feed tray 5 that has fed the paper P is extracted from the storage unit, and the length of the paper P when the leading edge reaches the registration roller pair 18 is obtained. It is possible to determine whether or not the length reaches the pair of paper feed unit exit rollers 45.

  When the length of the paper P is the length that reaches the paper feed unit exit roller pair 45 (“Yes” in S2), the paper feed unit exit roller pair 45, the relay roller pair 43, and the registration roller pair 18 are rotationally driven. Let When the width direction position detection sensor 46 detects the sheet P, the relay roller pair 43 is separated (S3), and the rotation drive of the relay roller pair 43 is stopped. After the relay roller pair 43 is separated, the registration roller pair 18 and the paper feed unit outlet roller pair 45 perform a shift operation while the registration roller pair 18 and the paper feed unit outlet roller pair 45 are rotationally driven. Perform (S4). When the shift operation is finished, the paper feed unit outlet roller pair 45 is separated (S5), and the position of the paper feed unit outlet roller pair 45 in the width direction is set while the paper P is being conveyed while the registration roller pair 18 is rotationally driven. Return to the initial position (S6). Thereafter, the trailing edge detection sensor 47 detects the passage of the trailing edge of the paper P (S7), and after a predetermined time (several milliseconds in this embodiment) has elapsed, the pair of paper feeding unit outlet rollers 45 is brought into contact (S8). The next sheet P is received (S9).

When the length of the paper P is not the length that reaches the paper feed unit exit roller pair 45 (“No” in S2), the relay roller pair 43 and the registration roller pair 18 are rotationally driven to detect the width direction position detection sensor 46. When the paper P is detected, the relay roller pair 43 is separated (S10). Thereafter, the shift operation is performed only with the registration roller pair 18 (S11), and the next sheet P is received (S9).
When the sheet P to be transported is short, the shift operation is performed only with the registration roller pair 18, so that the pair of sheet feeding unit exit rollers 45 remains in contact with each other at the initial position, and the next sheet P is loaded. It becomes possible to shorten the time to accept. For this reason, productivity can be maintained without delay with respect to the next sheet feeding operation.

In the pre-transfer conveying unit 300 of the reference configuration example 2, after the shift operation is performed by the registration roller pair 18 and the paper feeding unit outlet roller pair 45, the rear end of the paper P passes through the paper feeding unit outlet roller pair 45. The operation of returning the position in the width direction of the paper feed unit outlet roller pair 45 to the initial position is performed.
In contrast, in the pre-transfer conveyance unit 300 according to the present embodiment, after the shift operation is performed by the registration roller pair 18 and the sheet feeding unit exit roller pair 45, the sheet feeding unit is immediately performed regardless of the position of the sheet P. The exit roller pair 45 is separated. For this reason, the operation of returning the position in the width direction of the paper feed unit outlet roller pair 45 to the initial position can be started before the trailing edge of the paper P leaves the position sandwiched between the paper feed unit outlet roller pair 45.
Further, the pair of paper feed unit exit rollers 45 that have been separated and returned to the initial position are two rollers after a predetermined time (several milliseconds) has elapsed since the paper P being conveyed has passed through the detection position of the trailing edge detection sensor 47. Control to touch.

  As described above, the pre-transfer conveyance unit 300 according to the present embodiment starts the operation of returning the position in the width direction of the paper feed unit outlet roller pair 45 to the initial position earlier than the pre-transfer conveyance unit 300 of the reference configuration example 2. be able to. As a result, the time until the next sheet P is received can be shortened, and the space between the sheets can be reduced. Productivity can be maintained without delay with respect to the next sheet feeding operation.

  FIG. 10 is a top view of the vicinity of the width direction position detection sensor 46 for explaining the width direction position detection sensor 46 for detecting the position of the paper P in the width direction. The width direction position detection sensor 46 is installed at a position immediately after passing the registration roller pair 18 in the paper transport path 19. The width direction position detection sensor 46 includes a plurality of photosensors each including a light emitting element such as an LED and a light receiving element such as a photodiode in the width direction (vertical direction in FIG. 10). Then, by detecting the position of the paper edge PE which is the widthwise edge of the paper P, the amount of deviation of the horizontal position of the paper P is detected. That is, the width direction position detection sensor 46 detects the amount of positional deviation in the width direction of the paper P that is transported through the paper transport path 19 of the pre-transfer transport unit 300. Therefore, based on the detection result of the width direction position detection sensor 46, the lateral position correction by the registration roller pair 18 and the sheet feeding unit exit roller pair 45 (or the lateral position correction by only the registration roller pair 18) is performed. Is called.

  In the present embodiment, as shown in FIG. 10, the width direction position detection sensor 46 is installed only on one end side in the width direction to detect the position of the sheet end PE on the one end side in the width direction of the sheet P. The width direction position detection sensor 46 may be installed over the entire width direction. In this case, it is possible to detect the position of each paper edge PE at both ends in the width direction of the paper P. Further, the width direction position detection sensor 46 is not limited to the configuration shown in FIG. 10 as long as the position in the width direction of the paper P can be detected.

FIG. 11 is an explanatory diagram of the relay roller contact / separation mechanism 30 that contacts and separates the relay roller pair 43. FIG. 11A is a perspective explanatory view of the relay roller contact / separation mechanism 30, and FIG. 11B is a cross-sectional explanatory view.
The relay inner roller 43a is a drive roller, and is driven to rotate by transmitting rotational drive from the relay roller pair drive motor 430 to the relay drive shaft 38.

  The relay outer roller 43 b is a driven roller, and the relay driven rotating shaft 36 to which the relay outer roller 43 b is fixed is rotatably supported by the relay slide bearing member 39. The relay slide bearing member 39 is assembled to the housing of the printer 100 main body so as to be slidable only in the moving direction of the relay outer roller 43b. The relay biasing spring 37 is a compression spring that biases the relay slide bearing member 39 toward the relay inner roller 43a.

In the relay roller contact / separation mechanism 30, when the relay roller contact / separation drive source 431 is driven, the relay contact / separation pressing element 32 protrudes rightward in FIG. 11A and presses the separation force input lever 33. . The separation force input lever 33 is fixed to a relay separation lever rotating shaft 34 to which the relay separation lever 35 is fixed. When the separation force input lever 33 is pressed by the relay contact / separation pressing element 32, the separation force input lever 33 rotates in the direction of arrow "D" in FIG. At this time, the relay separation lever 35 fixed to the relay separation lever rotation shaft 34 together with the separation force input lever 33 also rotates by the same rotation amount as the separation force input lever 33.
In FIG. 11B, the separation force input lever 33 located on the near side of the cross section shown in the drawing is indicated by a broken line for convenience.

  As shown in FIG. 11, the relay separation lever 35 has a bent portion on the distal end side, and the relay driven rotary shaft 36 is hooked on the bent portion. When the relay separation lever 35 rotates in the direction of the arrow “D” in FIG. 11, a force that pushes up the relay driven rotary shaft 36 acts, and the relay outer roller 43 b resists the biasing force of the relay biasing spring 37 in FIG. b) Move in the direction of the arrow “E” in the middle, and move away from the relay inner roller 43a.

Next, the sheet feeding unit outlet roller pair 45 is driven to rotate, and the sheet feeding unit outlet driving mechanism 600 that shifts and separates is described.
FIG. 12 is an explanatory diagram of the paper feed unit outlet drive mechanism 600. FIG. 12A shows a state where the sheet feeding unit outlet inner roller 45a and the sheet feeding unit outlet outer roller 45b of the pair of sheet feeding unit outlet rollers 45 are in contact with each other, and FIG. The state where the roller 45a and the sheet feeding unit outlet outer roller 45b are separated from each other is shown.

The paper feed unit outlet drive mechanism 600 includes a shift unit 60 that is slidable in the width direction (a direction perpendicular to the paper surface in FIG. 2) with respect to the printer 100 main body. The shift unit 60 supports the sheet feeding unit outlet inner roller 45a and the sheet feeding unit outlet outer roller 45b, the sheet feeding unit outlet roller contact / separation motor 451, and the sheet feeding unit outlet roller pair drive motor 450, and is integrated. In this configuration, the printer 100 is slid relative to the main body. The shift unit 60 includes a rack gear unit 69 to which driving for shifting is input.
When the sheet feeding unit exit roller pair shift motor 452 arranged on the main body side of the printer 100 is driven, the shift drive output gear 68 rotates in the arrow “G” direction in FIG. As a result, the drive that moves in the width direction is input to the rack gear portion 69 that meshes with the shift drive output gear 68, and the shift unit 60 moves in the width direction (arrow “H” direction in FIG. 12A).

The sheet feeding unit outlet inner roller 45a is supported to be rotatable about the sheet feeding unit outlet inner roller shaft 64 with respect to the casing of the shift unit 60, and is driven by the sheet feeding unit outlet roller pair drive motor 450. Thus, it is driven to rotate in the direction in which the paper P is conveyed.
The sheet feeding unit outlet outer roller 45 b is supported by the contact / separation holder 61 so as to be rotatable about the sheet feeding unit outlet outer roller shaft 63. The contact / separation holder 61 is slid in a direction (vertical direction in FIG. 12) in which the sheet feeding unit outlet outer roller 45b is brought into contact with and separated from the housing of the shift unit 60 by a guide mechanism provided in the housing of the shift unit 60. Held possible.

  The shift unit 60 includes a contact / separation compression spring 62 that abuts against the housing of the shift unit 60 and the contact / separation holder 61 and biases the contact / separation holder 61 toward the inner roller 45a of the sheet feeding unit outlet. In a state where no other external force is applied to the contact / separation holder 61, the contact / separation holder 61 is urged toward the sheet feeding unit outlet inner roller 45 a by the urging force of the contact / separation compression spring 62. As a result, the sheet feeding unit outlet outer roller 45b rotatably supported by the contact / separation holder 61 contacts the sheet feeding unit outlet inner roller 45a. With the sheet feeding unit outlet outer roller 45b in contact with the sheet feeding unit outlet inner roller 45a, the sheet feeding unit outlet inner roller 45a is driven to rotate, whereby the sheet feeding unit outlet outer roller 45b is driven to rotate.

  The shift unit 60 includes a contact / separation cam 65 against which the contact / separation holder 61 abuts. The contact / separation cam 65 is fixed to the contact / separation cam rotation shaft 66. When the contact / separation cam rotation shaft 66 is rotated by driving the paper feed unit outlet roller pair contact / separation motor 451, the contact / separation cam rotation shaft 66 is rotated. The contact / separation cam 65 also rotates.

  From the state shown in FIG. 12 (a), the paper feed unit exit roller contact / separation motor 451 is driven, and the contact / separation cam rotating shaft 66 and the contact / separation cam 65 rotate in the direction of arrow "I" in FIG. Then, the contact / separation cam 65 presses the contact / separation holder 61 in the direction of the arrow “J” in FIG. The contact / separation holder 61 pressed by the contact / separation cam 65 moves in a direction away from the sheet feeding portion outlet inner roller 45a against the urging force of the contact / separation compression spring 62. As a result, the sheet feeding unit outlet outer roller 45b supported by the contact / separation holder 61 is separated from the sheet feeding unit outlet inner roller 45a to be in the state shown in FIG.

As described above, the shift unit 60 supports the sheet feeding unit outlet inner roller 45a and the sheet feeding unit outlet outer roller 45b, the sheet feeding unit outlet roller contact / separation motor 451, and the sheet feeding unit exit roller pair drive motor 450. In this configuration, the printer 100 is slid integrally with the printer 100 main body. Further, the sheet feed unit exit roller pair contact / separation motor 451, the sheet feed unit exit roller pair drive motor 450, and the sheet feed unit exit roller pair shift motor 452 can be independently driven.
With these configurations, the shift operation can be performed in a state in which the sheet feeding unit outlet inner roller 45a and the sheet feeding unit outlet outer roller 45b are separated from each other.
Further, with the above-described configuration, the shift operation is performed in a state where the sheet feeding unit outlet inner roller 45a and the sheet feeding unit outlet outer roller 45b are in contact with each other and the sheet feeding unit outlet inner roller 45a is rotationally driven. Can do. That is, the shift operation can be performed while transporting the paper P in the transport direction.

[Modification]
Next, a modified example of the paper feed unit outlet drive mechanism 600 will be described.
FIG. 13 is an explanatory diagram of a sheet feeding unit outlet driving mechanism 600 according to a modification. FIG. 13A shows a state where the sheet feeding unit outlet inner roller 45a and the sheet feeding unit outlet outer roller 45b of the pair of sheet feeding unit outlet rollers 45 are in contact with each other, and FIG. The state where the roller 45a and the sheet feeding unit outlet outer roller 45b are separated from each other is shown.

  The paper feed unit outlet drive mechanism 600 of the modification is similar to the paper feed unit exit drive mechanism 600 of the embodiment shown in FIG. 12 in the width direction (direction perpendicular to the paper surface in FIG. 2) with respect to the printer 100 main body. A slidable shift unit 60 is provided. The shift unit 60 includes a paper feeding unit outlet inner roller 45a and a paper feeding unit outlet outer roller 45b, a paper feeding unit outlet roller contact / separation motor 451, and a paper feeding unit outlet roller pair drive motor 450. A roller contact / separation mechanism 80 is provided inside. Then, each member constituting the sheet feeding unit outlet roller contact / separation mechanism 80 is supported and slid with respect to the main body of the printer 100 integrally.

  The shift unit 60 includes a rack gear unit 69 to which driving for shifting is input. Similarly to the paper feed unit exit drive mechanism 600 shown in FIG. 13, the shift unit 60 is driven in the width direction (FIG. 13) by driving the paper feed unit exit roller pair shift motor 452 and rotating the shift drive output gear 68. (A) It moves to the arrow "H" direction).

  FIG. 14 is an explanatory diagram of the sheet feeding unit outlet roller contact / separation mechanism 80 disposed in the shift unit 60 of the modified example. FIG. 14A is a perspective explanatory view of the sheet feeding unit outlet roller contact / separation mechanism 80, and FIG. 14B is a cross-sectional explanatory view. FIGS. 14A and 14B both show a state in which the sheet feeding unit outlet inner roller 45a and the sheet feeding unit outlet outer roller 45b are in contact with each other.

The sheet feeding unit outlet inner roller 45a is supported to be rotatable about the sheet feeding unit outlet inner roller shaft 64 with respect to the casing of the shift unit 60, and is driven by the sheet feeding unit outlet roller pair drive motor 450. Thus, it is driven to rotate in the direction in which the paper P is conveyed.
The sheet feeding unit outlet outer roller 45 b is supported by the contact / separation bearing member 67 so as to be rotatable about the sheet feeding unit outlet outer roller shaft 63. The contact / separation bearing member 67 is moved in a direction (vertical direction in FIG. 13) in which the sheet feeding unit outlet outer roller 45b is brought into contact with or separated from the housing of the shift unit 60 by a guide mechanism provided in the housing of the shift unit 60. It is held slidably.

  The paper feed unit outlet roller contact / separation mechanism 80 abuts against the housing of the shift unit 60 and the contact / separation bearing member 67 and contacts / separates compression that urges the contact / separation bearing member 67 toward the paper feed unit outlet inner roller 45a. A spring 62 is provided. In a state where no other external force is applied to the contact / separation bearing member 67, the contact / separation bearing member 67 is biased toward the sheet feeding unit outlet inner roller 45 a by the biasing force of the contact / separation compression spring 62. As a result, the sheet feeding unit outlet outer roller 45b rotatably supported by the contact / separation bearing member 67 contacts the sheet feeding unit outlet inner roller 45a. With the sheet feeding unit outlet outer roller 45b in contact with the sheet feeding unit outlet inner roller 45a, the sheet feeding unit outlet inner roller 45a is driven to rotate, whereby the sheet feeding unit outlet outer roller 45b is driven to rotate.

The paper feed unit exit roller pair contact / separation mechanism 80 includes a contact / separation cam rotation shaft 66 that rotates by driving of the paper feed unit exit roller pair contact / separation motor 451, and a contact / separation cam 65 fixed to the contact / separation cam rotation shaft 66. Is provided. Further, a contact / separation lever rotation shaft 71 that is rotatable with respect to the housing of the shift unit 60, a contact / separation cam pressing lever 70 that is fixed to the contact / separation lever rotation shaft 71 and is pressed by the contact / separation cam 65, And an approach / separation lever 72 fixed to the lever rotation shaft 71.
In FIG. 14B, the contact / separation cam 65 and the contact / separation cam pressing lever 70 located on the near side of the cross section shown in the drawing are indicated by broken lines for convenience.

  In a state where the two rollers shown in FIGS. 13A and 14 are in contact, the short side portion of the elliptical contact / separation cam 65 is in contact with the contact / separation cam pressing lever 70. When the paper feed unit exit roller contact / separation motor 451 is driven from the state shown in FIGS. 13A and 14, the contact / separation cam rotating shaft 66 and the contact / separation cam 65 are moved to the arrows in FIGS. 13A and 14. Rotate in “I” direction. By this rotation, the distance from the rotation center of the portion of the peripheral surface of the elliptical contact / separation cam 65 that contacts the contact / separation cam pressing lever 70 becomes longer, and the contact / separation cam 65 presses the contact / separation cam pressing lever 70. Then, the contact / separation cam pressing lever 70 rotates about the contact / separation lever rotation shaft 71 in the direction of the arrow “K” in FIGS. 13A and 14. At this time, the contact / separation lever rotating shaft 71 and the contact / separation lever 72 rotate together with the contact / separation cam pressing lever 70 by the same amount of rotation as the contact / separation cam pressing lever 70.

  When the contact / separation lever 72 rotates in the direction of the arrow “K” in FIGS. 13A and 14, the contact / separation cam pressing lever 70 contacts the sheet feeding unit outlet outer roller shaft 63 and further rotates, A force for pushing up the paper portion outlet outer roller shaft 63 is applied. As a result, the sheet feeding unit outlet outer roller 45b moves in the direction of the arrow “L” in FIGS. 13A and 14 against the urging force of the contact / separation compression spring 62, as shown in FIG. 13B. As described above, the sheet feeding unit outlet outer roller 45b is separated from the sheet feeding unit outlet inner roller 45a.

  The sheet feeding unit outlet drive mechanism 600 according to the modification can perform a shift operation in a state where the sheet feeding unit outlet inner roller 45a and the sheet feeding unit outlet outer roller 45b are separated from each other, as in the above-described embodiment. Further, the shift operation can be performed in a state where the sheet feeding unit outlet inner roller 45a and the sheet feeding unit outlet outer roller 45b are in contact with each other and the sheet feeding unit outlet inner roller 45a is rotationally driven. That is, the shift operation can be performed while transporting the paper P in the transport direction.

  The registration roller pair 18 is also a shift roller pair in which two rollers can come in contact with and separate from each other, like the paper feed unit outlet roller pair 45. For this reason, as the registration driving mechanism for rotating and shifting and separating the registration roller pair 18, the sheet feeding unit outlet driving mechanism 600 of the embodiment shown in FIG. 12 and the sheet feeding of the modification shown in FIGS. 13 and 14 are used. A configuration similar to that of the part exit drive mechanism 600 can be used.

  In the above-described embodiment, the case where the two pairs of shift rollers that perform the shift operation with the paper P interposed therebetween is the registration roller pair 18 and the paper feed unit outlet roller pair 45 is described, but the present invention is not limited to this. The two pairs of shift rollers may be a combination of two pairs of transport rollers. For example, the registration roller pair 18 and the relay roller pair 43 may perform a shift operation with the paper P interposed therebetween. However, if the distance between the two pairs of shift rollers in the paper transport path 19 is short, if the paper P is long in the transport direction, the skew may occur in the paper P during the shift operation as described with reference to FIG. There is. For this reason, two pairs of transport rollers at positions where no skew occurs in the paper P even when the maximum length of paper P that can be transported is sandwiched between the two pairs of shift rollers and the shift operation is performed are used as the shift roller pair. Is desirable.

In the above-described embodiment, the shift roller pair in which the pair of nipping and conveying members that shift the sheet with the two nipping and conveying members is formed by the two roller members has been described. However, the nipping and conveying member that forms the pair of nipping and conveying members It is not limited to two roller members. For example, a configuration in which a sheet is sandwiched between belt members or a configuration in which a sheet is sandwiched between a belt member and a roller member may be used.
Further, the pair of nipping and conveying members is not limited to the configuration in which both of the two nipping and conveying members that sandwich the sheet are surface moving bodies such as roller members or belt members. At least one of the two nipping / conveying members that sandwich the sheet by applying pressure may be a surface moving body that can move the surface to convey the sheet. For example, a roller member that is a surface moving body and a plate member that does not move on the surface are provided as two nipping and conveying members, and a conveying force is applied to the sandwiched sheet by rotating the roller member while sandwiching the sheet. It may be configured to be conveyed while being rubbed with the plate member.

[Second Embodiment]
In the above-described embodiment, the sheet conveying apparatus according to the present invention is applied to the sheet conveying unit of the printer 100 which is an image forming apparatus. Hereinafter, an example in which the sheet conveying apparatus according to the present invention is applied to an automatic document conveying apparatus will be described as a second embodiment.

FIG. 15 is a schematic configuration diagram of a copier 500 that is an image forming apparatus including the automatic document feeder according to the second embodiment.
The copying machine 500 has a configuration in which an image reading device 400 is arranged above the printer 100 shown in FIG. The image reading apparatus 400 includes an ADF 8 that is an automatic document feeder and a scanner 9 that is an image reading unit.
The printer 100 included in the copier 500 can form on the paper P based on image information input from an input terminal such as a personal computer or the operation panel 3, as in the printer 100 of the above-described embodiment. Further, the printer 100 included in the copying machine 500 can form an image on the paper P based on the image reading device 400.

FIG. 16 is a schematic configuration diagram of the image reading apparatus 400.
The image reading apparatus 400 is configured to be switchable between a flat bed scanner mode (placed document reading mode) and a DF scanner mode (conveyed document reading mode).

The flatbed scanner mode is executed when a read start request operation such as pressing of a copy start button is performed in a state where an original is placed on the flatbed contact glass 113 on the upper part of the scanner 9, and an image of the placed original is displayed. This is a reading operation mode. Light is applied to the image surface of the document while moving the image reading unit 116 in the moving reading region 111 directly below the flat bed contact glass 113. Then, the reflected image from the image surface of the original is converted into an image signal so that the image of the original is read.
The DF scanner mode is an operation mode in which the image reading unit 116 is stopped in the stop reading area 112 immediately below the DF contact glass 114 and the conveyed document image is read.

  In the DF scanner mode, the ADF 8 separates the original sheets one by one from the bundle of original sheets stacked on the original placement tray 121 (original placement table) and carries the original sheets into the original conveyance path 122. Convey along. During the conveyance, the document sheet is partially opposed to the upper surface of the DF contact glass 114 sequentially from the upstream portion in the conveyance direction.

  The ADF 8 is attached to the rear portion on the upper surface side of the scanner 9 (the portion on the back surface side in FIGS. 15 and 16) via an opening / closing mechanism such as a hinge. The ADF 8 can take an open position where the flatbed contact glass 113 is opened with respect to the scanner 9 and a closed position where the original on the flatbed contact glass 113 can be pressed.

  The image reading unit 116 may be any device such as a CCD module or a CIS module that can read the image on the surface side of the document by repeatedly scanning the line at a predetermined image reading position. Further, a fixed image reading unit fixed to the stop reading region 112 and a moving reading unit that moves along the flat bed contact glass 113 in the moving reading region 111 may be provided.

  The document placing tray 121 is mounted with left and right movable side guide plates 123 for positioning a document sheet set on the ADF 8 in a sheet width direction orthogonal to the sheet feeding direction. These side guide plates 123 can be relatively approached and separated from each other so that the document placement tray 121 and the center of the document sheet in the width direction coincide with each other. However, the side guide plate 123 may be arranged such that only one edge of the document sheet is brought into contact with one edge of the document placing tray 121 so that only the other edge can be moved.

  The ADF 8 is covered with a cover 138 that can be opened and closed at least above. Further, a main guide portion that forms the document conveyance path 122 of the ADF 8 is formed by a rib or the like formed on the cover 138. On the other hand, the ADF 8 is for calling a document set on the document placing tray 121 in the sheet feeding direction and a document called by the calling roller 124 in the sheet feeding direction toward the document conveyance path 122. A feed roller 125 and a separation pad 143 are provided.

  The ADF 8 transports a document fed into the document transport path 122 by the feed roller 125 in a posture in which an image can be read on the DF contact glass 114, and a transport unit 127 that transports the document after image reading to the discharge port 136. I have.

  The conveyance unit 127 reverses the original sheet separated and carried by the feed roller 125 and the like so as to be folded along the original conveyance path 122, and passes a predetermined reading position on the upper surface of the DF contact glass 114. Transport the original sheet. For such document conveyance, the first conveyance roller pair 128, the second conveyance roller pair 129, and the leading edge in the conveyance direction of the document sheet are detected on the upstream side of the DF contact glass 114 in the document conveyance path 122. A document registration sensor 131 is provided. Further, an abutment sensor 154 that detects that the document sheet has passed through the separation nip formed by the feed roller 125 and the separation pad 143 is provided on the upstream side of the first conveyance roller pair 128 in the document conveyance path 122. It has been.

  The ADF 8 includes a document conveyance control unit 7 that controls swinging of the calling roller 124 and driving of each roller indicated by an arrow “γ” in FIG. 16 based on the detection result of each sensor.

  The document sheet separated by the feed roller 125 or the like is conveyed so as to pass over the DF contact glass 114 by the first conveying roller pair 128 and the second conveying roller pair 129. Then, based on the detection timing of the leading edge of the document sheet by the document registration sensor 131, the image reading unit 116 reads the document surface image in a timely manner.

  For example, when the leading edge of the document sheet is detected by the document registration sensor 131, the timing at which the leading edge position of the document sheet that can be detected by the pulse count of the document feeding motor as a driving source reaches the reading position on the DF contact glass 114 is reached. Identified. A gate signal indicating an effective image area in the sub-scanning direction on the surface of the original sheet starts to be transmitted, and the gate signal continues to be transmitted until the rear end position of the original sheet passes the reading position.

  When reading of the back side image of the original sheet is requested, the back side image is read by a back side image reading module 135 (second image reading unit) including a contact image sensor for reading the back side.

  The back surface image reading module 135 includes a light source unit that irradiates light on the document sheet based on a lighting signal from the control unit, a plurality of sensor chips that receive reflected light from the document sheet, and signals output from the sensor chips. And a plurality of amplifying units for amplifying the signal. The back image reading module 135 also includes an A / D converter that converts the signal amplified by the amplifier from an analog signal to a digital signal, and an image processor that performs image processing on the digitally converted signal. .

  Further, the back image reading module 135 includes an output control circuit that performs output control of signals stored in the frame memory based on a timing signal from the control unit, and an interface that outputs a signal from the output control circuit to the printer 100 side. It has a circuit etc. The back side image reading timing by the back side image reading module 135 is controlled in substantially the same manner as the front side image reading timing, and the original after reading is discharged to the original discharge tray 139.

  On the downstream side of the DF contact glass 114 in the document conveyance path 122, a reading exit roller 132 for conveying the image-read document on the front side to the back image reading module 135 side is provided. On the downstream side of the reading exit roller 132, a white guide member 133 that faces the back image reading module 135, and a document discharge roller 137 that is positioned on the downstream side of the back image reading module 135 and the white guide member 133, Each is provided.

  The white guide member 133 has a guide function for moving the transported document along the back surface image reading module 135, and is a white reference surface for shading correction disposed so as to face the back surface image reading module 135 in the entire main scanning direction. have.

  In the ADF 8, the first conveying roller pair 128 and the second conveying roller pair 129 are shift roller pairs that shift the position of the original sheet in the sheet width direction by moving in the sheet width direction with the original sheet sandwiched therebetween. is there. The document registration sensor 131 that detects the leading edge of the document sheet in the conveyance direction is a sensor that can detect the arrival of the document sheet at the detection position and the position of the reached document sheet in the width direction.

When the position of the edge in the sheet width direction of the document sheet conveyed by the document registration sensor 131 is detected, the document conveyance control unit 7 calculates a correction amount in the width direction of the document sheet. Then, the position of the original sheet in the sheet width direction is corrected by performing a shift operation for moving the first conveyance roller pair 128 and the second conveyance roller pair 129 in the sheet width direction based on the calculated correction amount.
The positional deviation of the document sheet in the sheet width direction is likely to occur when the user places the document sheet on the document placing tray 121. As in the case of the ADF 8 of the second embodiment, if the shift operation is performed and the positional deviation of the original sheet in the sheet width direction is corrected, the user can place the original sheet on the original placement tray 121. The required accuracy of placing the original sheet can be relaxed.

  When the leading edge of the document sheet passes the detection position of the document registration sensor 131, the document conveyance control unit 7 performs control to separate the feed roller 125 and the separation pad 143. Thus, when the shift operation is performed using the first transport roller pair 128 and the second transport roller pair 129, the separation nip positioned upstream from the first transport roller pair 128 and the second transport roller pair 129 is the original. It is possible to prevent the sheet from being disturbed.

  After separating the feed roller 125 and the separation pad 143, the document conveyance control unit 7 drives a drive mechanism that shifts the first conveyance roller pair 128 and a drive mechanism that shifts the second conveyance roller pair 129, respectively. . As a result, the first transport roller pair 128 and the second transport roller pair 129 are shifted in synchronization with the original sheet sandwiched between the first transport roller pair 128 and the second transport roller pair 129. When the document sheet is moved in the sheet width direction by the calculated correction amount in the sheet width direction and the shift operation is completed, the drive mechanism that contacts and separates the first transport roller pair 128 is driven to connect the first transport outer roller 128b to the first transport outer roller 128b. The first conveying inner roller 128a is separated. Thereafter, the original sheet is conveyed only by the second conveying roller pair 129.

  When the first conveying roller pair 128 is separated, the drive mechanism for shifting the first conveying roller pair 128 is driven, and the position of the first conveying roller pair 128 in the sheet width direction is the position before the shift operation described above. Return to the initial position. A drive mechanism that contacts and separates the first transport roller pair 128 when the position of the first transport roller pair 128 in the sheet width direction is the initial position and the trailing edge of the original sheet passes the position of the first transport roller pair 128; The two rollers of the first conveying roller pair 128 are brought into contact with each other by driving.

In the ADF 8, when a document sheet shorter than the distance of the document transport path 122 from the first transport roller pair 128 to the second transport roller pair 129 is transported, only the second transport roller pair 129 is shifted in the sheet width direction. A configuration may be adopted.
On the other hand, when a document sheet longer than the distance of the document transport path 122 from the first transport roller pair 128 to the second transport roller pair 129 is transported, the first transport roller pair 128 and the second transport roller pair 129 The two pairs of rollers are moved in the width direction with the original sheet sandwiched therebetween. Since the original sheet is sandwiched and shifted by the first conveying roller pair 128 and the second conveying roller pair 129, the rotation moment is prevented from acting on the original sheet during the shift operation, and the original operation is performed on the original sheet by the shift operation. The occurrence of skew can be suppressed.

  Further, after the shifting operation of the first conveying roller pair 128 and the second conveying roller pair 129 is finished, the first conveying roller pair 128 separates the rollers, and the second conveying roller pair 129 alone conveys the original sheet. I do. At this time, the two rollers of the first conveying roller pair 128 are separated before the trailing edge of the original sheet passes through the position between the first conveying roller pair 128. As a result, it is possible to suppress the original sheet from being affected by the skew component (the force for inclining the original sheet with respect to the conveying direction) of the first conveying roller pair 128. Therefore, it is possible to suppress the document sheet from being inclined with respect to the sheet conveyance direction, and it is possible to improve the conveyance accuracy of the document sheet.

Further, by improving the conveyance accuracy of the original sheet, the positional accuracy of the original sheet at a position facing the DF contact glass 114 and the back image reading module 135 for reading the image of the original sheet is improved. Thereby, when the image reading apparatus 400 reads an image on an original sheet, it is possible to suppress the positional deviation of the read image, and it is possible to improve the accuracy of image information obtained by reading.
By improving the accuracy of the image information obtained by reading by the image reading device 400, the image accuracy of the image formed on the paper P formed by the printer 100 of the copying machine 500 can be improved. Thus, the performance of copying a document can be improved.

  The “sheet” conveyed by the sheet conveying apparatus according to the present invention includes paper, coated paper, an OHP sheet, label paper, a film, a fabric, and the like. In addition, "sheets" are resin sheets, protective paper on the front and back surfaces, metal sheets, electronic circuit board materials, special films, plastic films, prepregs, electronic circuit boards that have been subjected to metal foil such as copper foil or plating treatment, etc. Includes sheet for use. A prepreg is a sheet-like material in which a carbon fiber or the like is impregnated with a resin in advance. As an example of a prepreg, a fibrous reinforcing material such as carbon fiber or glass cloth is impregnated with a thermosetting resin mixed with additives such as a curing agent and a coloring agent, and heated or dried to be in a semi-cured state. Sheet-like reinforced plastic molding material.

  The sheet conveying apparatus according to the present invention is an apparatus that conveys a sheet-like member, and is generally applicable to devices that require prevention of skew in which the sheet-like member is inclined with respect to the conveying direction. . For example, the present invention can be applied to a processing apparatus that processes a sheet-like member.

  In addition, the “image forming device” with the configuration of the sheet conveying device attaches developer and ink to media such as paper, OHP sheet, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. Including an image forming apparatus. In addition, “image formation” includes not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium.

  What was demonstrated above is an example, and there exists an effect peculiar for every following aspect.

(Aspect 1)
Pre-transfer comprising two pairs of nipping and conveying member pairs such as a sheet feeding unit exit roller pair 45 and a registration roller pair 18 that can be conveyed while sandwiching a sheet such as paper P and moved in a width direction orthogonal to the conveying direction. In a sheet conveying apparatus such as the conveying unit 300, the sheet is moved in the width direction with one sheet sandwiched between two pairs of nipping and conveying members, and after moving in the width direction, two pairs of nipping and conveying member pairs Of the two nipping and conveying members forming the upstream nipping and conveying member pair such as the sheet feeding unit outlet roller pair 45 positioned upstream in the conveying direction (the sheet feeding unit outlet inner roller 45a and the sheet feeding unit outlet outer roller 45b). ), And the sheet is conveyed by the downstream nipping and conveying member pair such as the registration roller pair 18 positioned on the downstream side in the conveying direction of the two pairs of nipping and conveying members.
According to this, as described in the above embodiment, it is possible to prevent the sheet from being inclined with respect to the conveyance direction after adjusting the position in the width direction by sandwiching the sheet between the two pairs of sandwich conveyance members. This is due to the following reason.
That is, a pair of nipping and conveying members such as a conveying roller pair that conveys a sheet by sandwiching a sheet between two members generates a force that causes the sheet being conveyed to be inclined with respect to the conveying direction due to component errors or assembly errors. It is common. For this reason, if the sheet is transported while the sheet is sandwiched between the two pairs of sandwiching and conveying members after the sheet is sandwiched between the two pairs of sandwiching and conveying members and then the sheet is conveyed, the two pairs of sandwiching and conveying A force that tilts the sheet of the member pair acts on the sheet.
In the aspect 1, after the shift operation, the upstream-side nipping and conveying member pair is separated, and the sheet is conveyed by the downstream-side nipping and conveying member pair. For this reason, it can suppress that the force which inclines the sheet | seat of an upstream clamping conveyance member pair acts on a sheet | seat among the forces which incline the sheet | seat of two sets of clamping conveyance member pairs. Therefore, it is possible to suppress the sheet from being inclined with respect to the conveyance direction as compared with the configuration in which the sheet is continuously conveyed by the two pairs of sandwich conveyance members even after the shift operation.

(Aspect 2)
In the first aspect, after separating the two members of the upstream holding and conveying member pair, the upstream holding and conveying member pair is set to the initial position before the rear end of the sheet passes through the position between the upstream holding and conveying member pair. It is characterized by starting the return movement.
According to this, as described in the above embodiment, by starting the operation of returning to the initial position before the trailing edge of the sheet passes, the position in the width direction of the shifted upstream holding and conveying member pair is changed to the initial position. It is possible to start the operation of returning to swiftly. For this reason, it is possible to shorten the time until the next sheet is received.

(Aspect 3)
In the first or second aspect, a width direction position detection unit such as a width direction position detection sensor 46 that detects a position in the width direction of the sheet in the vicinity of the pair of downstream side nipping and conveying members is provided, and based on the detection result of the width direction position detection unit. Thus, the movement amount in the width direction of the two pairs of holding and conveying members during the shift operation is calculated.
According to this, as described in the above embodiment, the correction amount based on the position of the sheet immediately before performing the shift operation can be calculated, and the position of the sheet can be corrected appropriately.

(Aspect 4)
In any of the first to third aspects, when a sheet longer than the distance of the conveyance path such as the sheet conveyance path 19 from the upstream side clamping conveyance member pair to the downstream side conveyance conveyance member pair is conveyed, With the nipping and conveying member pairs sandwiching the sheet, the two nipping and conveying member pairs are moved in the width direction and are shorter than the distance of the conveying path from the upstream holding and conveying member pair to the downstream holding and conveying member pair. When the sheet is transported, only the downstream sandwiching and conveying member pair is moved in the width direction while the downstream sandwiching and transporting member pair sandwiches the sheet.
According to this, as described in the above-described embodiment, when the sheet to be conveyed is short, the upstream-side nipping / conveying member pair is in the state where the two nipping / conveying members remain in contact with or close to each other at the initial position. It becomes possible to shorten the time until the sheet is received.

(Aspect 5)
In any one of the first to fourth aspects, an upstream sheet detection unit such as a rear end detection sensor 47 that detects the presence / absence of a sheet on the upstream side in the conveyance direction with respect to the upstream holding conveyance member pair is provided, and the downstream sheet movement Based on the detection result of the upstream sheet detection means at the timing when the sheet arrives at the body pair, the length of the sheet to be conveyed is based on the distance of the conveyance path from the upstream nipping conveyance member pair to the downstream nipping conveyance member pair. It is also characterized by determining whether or not it is long.
According to this, as described in the above embodiment, it is possible to realize a configuration in which the control of the upstream side holding and conveying member pair is varied according to the length of the sheet.

(Aspect 6)
In any one of the first to fourth aspects, the sheet is conveyed based on the information (sheet P size information, etc.) of the sheet accommodated in the sheet accommodating unit such as the sheet feeding tray 5 that is the sheet conveying source of the sheet feeding device 200 or the like. It is characterized in that it is determined whether or not the length of the sheet to be processed is longer than the distance of the conveyance path from the upstream nip conveyance member pair to the downstream nip conveyance member pair.
According to this, as described in the above embodiment, it is possible to realize a configuration in which the control of the upstream side holding and conveying member pair is varied according to the length of the sheet.

(Aspect 7)
In an image forming apparatus such as a printer 100 including an image forming unit 2 for forming an image on a sheet such as a sheet P to be conveyed, an image forming unit such as an intermediate transfer belt 16 and a secondary transfer roller 15, the sheet is conveyed. The sheet conveying apparatus according to any one of aspects 1 to 6 is provided.
According to this, as described in the above embodiment, it is possible to suppress the positional deviation of the image formed on the sheet, and to improve the image accuracy of the image formed on the sheet.

(Aspect 8)
An automatic document conveying apparatus such as an ADF 8 that conveys an original sheet toward an image reading unit such as a scanner 9 that reads an image of an original sheet, has the configuration of the sheet conveying apparatus according to any one of aspects 1 to 6. It is characterized by.
According to this, as described in the second embodiment, the position in the width direction is determined by sandwiching the original sheet between the two pairs of nipping and conveying members of the first conveying roller pair 128 and the second conveying roller pair 129. After the adjustment, the original sheet can be prevented from being inclined with respect to the conveyance direction. Thereby, the conveyance accuracy of the original sheet can be improved.

(Aspect 9)
In an image reading apparatus such as an image reading apparatus 400 having an original conveying means for conveying an original sheet and an image reading means such as a scanner 9 for reading an image on the original sheet conveyed by the original conveying means, the original conveying means And an automatic document feeder such as the ADF 8 according to the eighth aspect.
According to this, as described in the second embodiment, it is possible to suppress the positional deviation of the read image when reading the image of the original sheet, and to improve the accuracy of the image information obtained by reading. .

(Aspect 10)
In an image forming apparatus such as a copying machine 500 including an image reading unit and an image forming unit such as the printer 100 that forms an image based on image information read by the image reading unit, the image reading unit is described in the ninth aspect. The image reading apparatus 400 or the like is provided.
According to this, as described in the second embodiment, it is possible to improve the image accuracy of the image formed based on the image of the original sheet.

DESCRIPTION OF SYMBOLS 1 Printer main body 2 Image forming unit 3 Operation panel 4 Paper discharge tray 5 Paper feed tray 8 ADF
9 Scanner 10 Laser Scanning Unit 11 Charging Device 12 Photoconductor 13 Developing Device 14 Primary Transfer Roller 15 Secondary Transfer Roller 16 Intermediate Transfer Belt 16a Secondary Transfer Opposed Roller 17 Fixing Device 18 Registration Roller Pair 18a Registration Roller 18b Registration Bottom Roller 19 Sheet transport path 21 Registration sensor 30 Relay roller contact / separation mechanism 32 Relay contact / separation pusher 33 Separation force input lever 34 Relay separation lever rotation shaft 35 Relay separation lever 36 Relay driven rotation shaft 37 Relay biasing spring 38 Relay drive shaft 39 Relay slide bearing member 40 Branch claw 41 Reverse roller pair 42 Double-sided roller pair 43 Relay roller pair 43a Relay inner roller 43b Relay outer roller 45 Feeder outlet roller pair 45a Feeder outlet inner roller 45b Feeder outlet outer roller 46 Width Direction position detection sensor 47 Rear end detection sensor 0 control unit 51 sheet feeding roller 52 separation conveyance roller 53 reverse roller 55 conveyance guide 60 before transfer 60 shift unit 61 contact / separation holder 62 contact / separation compression spring 63 sheet feeding unit outlet outer roller shaft 64 sheet feeding unit outlet inner roller shaft 65 contact / separation Cam 66 Contact / separation cam rotation shaft 67 Contact / separation bearing member 68 Shift drive output gear 69 Rack gear portion 70 Contact / separation cam pressing lever 71 Contact / separation lever rotation shaft 72 Contact / separation lever 80 Paper feed portion outlet roller contact / separation mechanism 100 Printer 111 Movement Reading area 112 Stop reading area 113 Flatbed contact glass 114 Contact glass 116 Image reading part 121 Document placing tray 122 Document conveying path 123 Side guide plate 124 Calling roller 125 Feed roller 127 Conveying part 128 First conveying roller pair 128a First conveying Inner roller 128b First transfer outer Roller 129 Second transport roller pair 131 Document registration sensor 132 Reading exit roller 133 White guide member 135 Back image reading module 136 Discharge port 137 Document discharge roller 138 Cover 139 Document discharge tray 143 Separation pad 180 Registration roller pair drive motor 181 Registration roller contact / separation motor 182 Registration roller pair shift motor 200 Paper feed device 300 Pre-transfer conveyance unit 400 Image reading device 430 Relay roller pair drive motor 431 Relay roller contact / separation drive source 450 Paper feed unit exit roller pair drive motor 451 Paper unit outlet roller pair contact / separation motor 452 Paper unit outlet roller pair shift motor 600 Paper unit outlet drive mechanism P Paper PE Paper edge

Patent 6010861

Claims (10)

In a sheet conveying apparatus provided with two pairs of nipping conveying members capable of conveying while sandwiching a sheet and moving in a width direction orthogonal to the conveying direction,
The sheet is moved in the width direction in a state where the sheet is sandwiched between two pairs of sandwiching conveyance members,
After the movement in the width direction, the two holding and conveying members forming the upstream holding and conveying member pair positioned on the upstream side in the conveying direction of the two sets of holding and conveying member pairs are separated, and two sets of The sheet conveying apparatus characterized in that the sheet is conveyed by a downstream nipping and conveying member pair located on the downstream side in the conveying direction of the nipping and conveying member pair. In the sheet conveying apparatus according to claim 1,
After separating the two holding and conveying members of the upstream holding and conveying member pair, before passing the position where the rear end of the sheet is pinched by the upstream holding and conveying member pair, the upstream holding and conveying member pair An operation of returning the position in the width direction to an initial position is started. In the sheet conveying apparatus according to claim 1 or 2,
A width direction position detecting means for detecting the position of the sheet in the width direction in the vicinity of the downstream holding and conveying member pair;
A sheet conveying apparatus that calculates the movement amounts of the two pairs of the nipping and conveying members when moving in the width direction based on the detection result of the width direction position detecting means. In the sheet conveying apparatus according to any one of claims 1 to 3,
When the sheet is transported longer than the distance of the transport path from the upstream side sandwiching and conveying member pair to the downstream side sandwiching and conveying member pair, the two pairs of sandwiching and conveying member pairs sandwich the sheet. , Moving the two pairs of the holding and conveying members in the width direction,
When the sheet that is shorter than the distance of the conveyance path from the upstream side clamping conveyance member pair to the downstream side clamping conveyance member pair is conveyed, the downstream side clamping conveyance member pair holds the sheet, The sheet conveying apparatus according to claim 1, wherein only the downstream nipping and conveying member pair is moved in the width direction. In the sheet conveying apparatus according to any one of claims 1 to 4,
An upstream sheet detecting means for detecting the presence or absence of the sheet on the upstream side in the transport direction with respect to the upstream holding and transporting member pair;
Based on the detection result of the upstream sheet detection means at the timing when the sheet arrives at the downstream holding and conveying member pair, the length of the sheet to be conveyed is changed from the upstream holding and conveying member pair to the downstream holding and holding member. It is judged whether it is longer than the distance of the conveyance path | route which reaches a conveyance member pair, The sheet conveying apparatus characterized by the above-mentioned. In the sheet conveying apparatus according to any one of claims 1 to 4,
The length of the sheet to be conveyed is the distance of the conveyance path from the upstream holding and conveying member pair to the downstream holding and conveying member pair based on the information of the sheet accommodated in the sheet accommodating unit that is the conveyance source of the sheet It is judged whether it is longer than this, The sheet conveying apparatus characterized by the above-mentioned. In an image forming apparatus including an image forming unit that forms an image on a conveyed sheet,
An image forming apparatus comprising the sheet conveying apparatus according to claim 1 as a structure for conveying the sheet. In an automatic document feeder that conveys the document sheet toward an image reading unit that reads an image of the document sheet,
An automatic document conveying apparatus comprising the configuration of the sheet conveying apparatus according to claim 1. An original conveying means for conveying an original sheet;
An image reading apparatus comprising: an image reading unit that reads an image on a document sheet conveyed by the document conveying unit;
An image reading apparatus comprising the automatic document feeder according to claim 8 as the document feeder. Image reading means;
In an image forming apparatus comprising: an image forming unit that forms an image based on image information read by the image reading unit;
An image forming apparatus comprising the image reading apparatus according to claim 9 as the image reading unit.

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