JP7085113B2 - Sheet transfer device, automatic document transfer device, image reading device and image forming device - Google Patents

Description

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

Conventionally, there is known a sheet transport device including two sets of sandwich transport member pairs capable of transporting a sheet by sandwiching it and moving it in a width direction orthogonal to the transport direction.
For example, in Patent Document 1, the first sandwiching roller and the second sandwiching roller are held in the width direction while the recording medium (sheet) is sandwiched between the first sandwiching roller and the second sandwiching roller (two sets of sandwiching transport members). It is described that it is moved to and corrects 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 sets of sandwiching and transporting member pairs and moved in the width direction, the sheet is transported with respect to the transporting direction after the above-mentioned positional deviation is corrected. Was sometimes tilted.

In order to solve the above-mentioned problems, the present invention is a sheet transport device including two sets of sandwich transport member pairs capable of transporting a sheet by sandwiching it and moving it in a width direction orthogonal to the transport direction. The sheet is moved in the width direction while being sandwiched between two sets of sandwiching and transporting member pairs, and after the movement in the width direction, upstream of the two sets of sandwiching and transporting member pairs in the transporting direction. The two sandwiching and transporting members forming the upstream pinching and transporting member pair located on the side are separated from each other, and the downstream side sandwiching and transporting member pair located on the downstream side in the transporting direction of the two sets of the sandwiching and transporting member pairs is said. An upstream sheet detecting means for transporting a sheet and detecting the presence or absence of the sheet on the upstream side in the transport direction from the upstream side pinching and transporting member pair is provided, and the timing at which the sheet reaches the downstream side pinching and transporting member pair. Whether or not the length of the sheet to be conveyed is longer than the distance of the transfer path from the upstream side holding transfer member pair to the downstream side holding transfer member pair based on the detection result of the upstream side sheet detecting means in If the length of the sheet to be transported is longer than the distance of the transport path from the upstream side pinch transport member pair to the downstream side pinch transport member pair, the upstream side pinch transport member pair is separated. However, if the length of the sheet to be transported is shorter than the distance of the transport path from the upstream side pinch transport member pair to the downstream side pinch transport member pair, the upstream side pinch transport member pair is not separated. It is a feature.

According to the present invention, there is an excellent effect that the sheet can be suppressed from tilting with respect to the transport direction after the position in the width direction is adjusted by sandwiching the sheet between two sets of sandwiching and transporting members.

It is explanatory drawing of the operation after the tip of the paper has passed the detection position of the width direction position detection sensor in the transfer part before transfer of this embodiment. The schematic block diagram of the printer which concerns on this embodiment. The enlarged explanatory view of the transfer part before transfer of this embodiment. The block diagram which shows the relationship between the roller pair arranged in the transfer part before transfer, a sensor, and a control part. Explanatory drawing of the transfer part before transfer of the reference configuration example 1. FIG. An explanatory diagram schematically showing a state in which paper is shifted by a pair of resist rollers in Reference Configuration Example 1. Explanatory drawing of the transfer part before transfer of the reference structure example 2. FIG. An explanatory diagram schematically showing a state in which the paper is shifted by the resist roller pair and the paper feed unit outlet roller pair in Reference Configuration Example 2. The flowchart of the shift operation of the transfer part before transfer of this embodiment. Top view near the position detection sensor in the width direction. Explanatory drawing of the relay roller pair contact / separation mechanism for connecting / detaching a relay roller pair. Explanatory drawing of the paper feed part outlet drive mechanism of embodiment. Explanatory drawing of the paper feed part outlet drive mechanism of a modification. Explanatory drawing of the feeding part outlet roller | contact and separation mechanism of a modification. The schematic block diagram of the copying machine provided with the automatic document transporting apparatus which concerns on 2nd Embodiment. The schematic block diagram of the image reading apparatus which concerns on 2nd Embodiment.

Hereinafter, as an image forming apparatus including the sheet transporting apparatus according to the present invention, an electrophotographic printer (hereinafter, simply referred to as a printer) that forms an image by an electromagnetic photography method will be described. In the present embodiment, a color laser printer will be described as an example of the image forming apparatus, but the image forming apparatus may be not limited to a color one but may be a monochrome one, and is not limited to a printer but may be a copying machine, a multifunction device, or the like. The image forming apparatus may be used. Further, the image forming apparatus provided with the sheet transporting apparatus according to the present invention is not limited to the electrophotographic method, and may be an image forming device of another type such as an inkjet method.

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

The image processing unit 2 includes a photoconductor 12 which is a latent image carrier facing the upholstered surface of the upper part of the intermediate transfer belt 16, and around the photoconductor 12, a charging device 11 which is a charging means and a latent image forming. It is provided with a laser scanning unit 10 as a means, a developing device 13 as a developing means, and the like. 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.
Further, a secondary transfer roller 15 is provided below the intermediate transfer belt 16, and a secondary transfer facing roller 16a facing the secondary transfer roller 15 with the intermediate transfer belt 16 interposed therebetween is provided to form a secondary transfer nip. ..

At the bottom of the printer main body 1, a paper feed device 200 having a first to third three-stage paper feed tray 5 is provided. The three paper feed trays 5 of the paper feed device 200 can be pulled out with respect to the printer main body 1, and each paper feed tray 5 accommodates a paper P made of transfer paper, a resin film, or the like. The paper feed device 200 includes a paper feed roller 51, a separate transfer roller 52, and a reverse roller 53 corresponding to each of the three-stage paper feed trays 5.

In the paper feeding device 200, the paper P fed by the paper feeding roller 51 is fed to the separation nip which is the contact portion between the separation transfer roller 52 and the reverse roller 53. When the drive is input from the drive motor, the separate transfer roller 52 is rotationally driven in the counterclockwise direction in FIG. 2 to apply a transfer force toward the downstream side in the transfer direction to the paper P.
The reverse roller 53 is in contact with the separate transfer roller 52. Drive is input from the drive motor so that the reverse roller 53 is rotationally driven in the counterclockwise direction in FIG.

In such a configuration, the surface movement direction at the separation nip of the separation transfer roller 52 and the reverse roller 53 is opposite, whereby the uppermost paper P in the bundle of paper P and the paper P below it are separated. , Only the top-level sheet P can be fed.

When image information is input from an input terminal such as a personal computer or an operation panel 3 in the printer 100 and the printing operation is started, the photoconductor 12 is rotationally driven in the counterclockwise direction in FIG. 2, and the intermediate transfer belt 16 is moved. 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 photoconductor 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 photoconductor 12. Then, 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 transfer is removed by the photoconductor cleaning device.

At the time of color image formation, the above-mentioned image formation operation is performed in all the image forming units 2, and the yellow toner image, the cyan toner image, the magenta toner image, and the black toner image formed on the individual photoconductors 12 are intermediate. It is sequentially stacked and transferred on the transfer belt 16.

On the other hand, the paper P is fed from the paper feed device 200. When the user selects the paper feed tray 5 to be used from the three-stage paper feed tray 5 by 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 displayed. It is fed.
The broken line indicated by the reference numeral "19" in FIG. 2 indicates a transport path through which the paper P passes through the printer 100.

The fed paper P is sent out toward the resist roller pair 18, and the tip of the paper P is abutted against the stopped resist roller pair 18. As shown in FIG. 2, a resist sensor 21 is arranged in the vicinity of the upstream side of the resist roller pair 18.
As a result, after the position of the tip of the paper P in the transport direction and the inclination with respect to the transport direction are matched, the resist roller pair 18 transfers the paper P to the secondary transfer nip at a timing that matches the toner image on the intermediate transfer belt 16. Send out towards. The transfer residual toner adhering to the surface of the intermediate transfer belt 16 after the toner image transfer at the secondary transfer nip is removed by the intermediate transfer belt cleaning device.

The paper P on which the unfixed toner image is transferred by 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 ejection tray 4 in the case of single-sided printing. Toner.
In the case of double-sided printing, the paper P on which the image is formed on the first surface is conveyed to the double-sided path by switching the conveying path by the branch claw 40. The paper P fed to the reversing roller pair 41 by the branch claw 40 is conveyed to the double-sided roller pair 42 by the forward / reversal of the reversing roller pair 41. At this time, the front and back sides of the paper P with respect to the transport direction are reversed from those when the image is formed on the first surface. Then, after the paper P is conveyed to the relay roller pair 43 and the resist roller pair 18, the image is formed on the second surface by the same process as described above, and then the paper P is discharged to the paper ejection tray 4.

As an option, the user can connect a paper feed bank capable of feeding a large amount of paper P to the printer main body 1 and a finisher capable of stitch binding and folding instead of the paper ejection tray 4.

The printer 100 includes a paper feed unit outlet roller pair 45 as a transport roller pair at the downstream end in the paper transport path 19 in the paper feed device 200.

FIG. 3 is an enlarged explanatory view of the pre-transfer transfer unit 300 that forms the paper transfer path 19 on the upstream side in the transfer direction of the paper P from the secondary transfer nip in the printer 100 shown in FIG. 2.
The pre-transfer transfer unit 300 includes a width direction position detection sensor 46 on the downstream side in the transfer direction near the resist roller pair 18, and a rear end detection sensor 47 on the upstream side in the transfer direction near the paper feed unit outlet roller pair 45. ..
The width direction position detection sensor 46 is a sensor capable of detecting the arrival of the paper P at the detection position and the width direction position of the reached paper P, and the rear end detection sensor 47 sets the detection position after the paper P. It is a sensor that can detect whether or not it has passed the edge.
A relay roller pair 43 is arranged in the paper transport path 19 between the paper feed unit outlet roller pair 45 and the resist roller pair 18.

FIG. 4 is a block diagram showing a relationship between the roller pair and the sensor arranged in the pre-transfer transfer unit 300 and the control unit 50 of the printer 100.
In the relay roller pair 43, the two rollers forming the roller pair can be brought into contact with each other. 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 drive source 431 that is a power source for the operation of connecting and disconnecting the two rollers of the relay roller pair 43. ..

The resist roller pair 18 is a shift roller pair that shifts the position of the paper P in the width direction by moving in the width direction orthogonal to the transport direction of the paper P while sandwiching the paper P. Further, the paper feed unit outlet roller pair 45 moves in the width direction orthogonal to the transport direction of the paper P while sandwiching the paper P together with the resist roller pair 18 to assist in maintaining the shift operation of the resist roller pair 18. A pair of shift rollers. Further, the resist roller pair 18 and the paper feed unit outlet roller pair 45 are capable of contacting and separating the two rollers forming the roller pair.

The printer 100 includes a resist roller pair drive motor 180 that inputs drive to the resist roller pair 18, and a resist roller pair contact / detachment motor 181 that is a power source for an operation of connecting and disconnecting the two rollers of the resist roller pair 18. Further, the resist roller pair shift motor 182 is provided as a power source for the shift operation of moving the resist roller pair 18 in the width direction.
Further, the printer 100 serves as a power source for the operation of connecting and separating the two rollers, the paper feed unit outlet roller pair drive motor 450 and the paper feed unit outlet roller pair 45, for inputting the drive to the paper feed unit outlet roller pair 45. It is provided with a paper feed unit outlet roller contact / detachment motor 451. Further, it is provided with a paper feed unit outlet roller pair shift motor 452 which is a power source for a shift operation for moving the paper feed unit outlet roller pair 45 in the width direction.

The tip of the paper P conveyed from the paper feed tray 5 passes in the order of the paper feed unit outlet roller pair 45 and the relay roller pair 43, and reaches the resist roller pair 18. When the transfer timing is adjusted by the resist roller pair 18 and the transfer toward the secondary transfer nip is restarted, the paper P is positioned at the end in the width direction (main scanning direction) 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. As a result, the correction amount based on the position of the paper P immediately before the shift operation can be calculated, and the position of the paper P can be appropriately corrected.

The misalignment of the paper P in the width direction tends to occur when the user sets the paper P in the paper feed tray 5. As a configuration for suppressing misalignment in the width direction, a side fence is provided on the paper feed tray 5, and the image is premised on the user arranging the side fence with high accuracy and setting the paper P with respect to the side fence with high accuracy. There is something that guarantees quality.
If the printer 100 of the present embodiment is configured to perform a shift operation and correct the misalignment of the paper P in the width direction, 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 the paper P longer than the distance of the paper transport path 19 from the paper feed unit outlet roller pair 45 to the resist roller pair 18 is conveyed to the transfer pre-transfer unit 300 of the present embodiment, and the tip of the paper P is shown. Is an explanatory view after passing through the detection position of the width direction position detection sensor 46.
FIG. 1A is an explanatory diagram immediately after the tip of the paper P has passed the detection position of the widthwise position detection sensor 46.

When the tip of the paper P passes the detection position of the width direction position detection sensor 46, the relay roller facing / detaching drive source 431 is driven to move the relay outer roller 43b in the direction of the arrow “A1” in FIG. 1 (b). It is moved to separate the relay inner roller 43a and the relay outer roller 43b. This makes it possible to prevent the relay roller pair 43 located upstream of the resist roller pair 18 from hindering the shift of the paper P when the shift operation is performed using the resist roller pair 18.

After separating the relay inner roller 43a and the relay outer roller 43b, the control unit 50 drives the resist roller vs. shift motor 182 and the paper feed unit outlet roller vs. shift motor 452, and the resist roller pair 18 and the paper feed unit The exit roller vs. 45 is synchronized and shifted. At this time, with the paper P sandwiched between the resist roller pair 18 and the paper feed unit outlet roller pair 45, the resist roller pair 18 and the paper feed unit outlet 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 and the shift operation is completed, the paper feed unit outlet roller contact / detachment motor 451 is driven. As a result, as shown in FIG. 1 (c), the paper feed section outlet outer roller 45b is moved away from the paper feed section outlet inner roller 45a (in the direction of the arrow "A2" in FIG. 1 (c)) to supply the paper. Separate the paper outlet inner roller 45a and the paper feed outlet outer roller 45b.

As described above, in the present embodiment, when the shift operation is completed, as shown in FIG. 1 (c), the paper feed section outlet roller pair 45 is separated from each other, and the paper P is conveyed only by the resist roller pair 18. When the paper feed unit outlet roller pair 45 is separated, the paper feed unit outlet roller pair shift motor 452 is driven, and the position of the paper feed unit outlet roller pair 45 in the width direction is the initial position before the shift operation described above. Return to position. When the position in the width direction of the paper feed unit outlet roller pair 45 becomes the initial position and the rear end of the paper P passes the position of the paper feed unit outlet roller pair 45, the paper feed unit outlet roller contact / detachment 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 resist roller pair 18, when the paper P is narrowly held by the secondary transfer nip, the resist roller pair contact / detachment motor 181 is driven. As a result, the resist upper roller 18a is moved away from the resist lower roller 18b, the resist upper roller 18a and the resist lower roller 18b are separated from each other, and the surface moving body (16, 15) forming the secondary transfer nip forms the paper. P is conveyed. When the resist roller pair 18 is separated, the resist roller pair shift motor 182 is driven to return the position of the resist roller pair 18 in the width direction to the initial position which is the position before the shift operation described above. When the position in the width direction of the resist roller pair 18 becomes the initial position and the rear end of the paper P passes the position of the resist roller pair 18, the resist roller pair contact / separation motor 181 is driven to drive the resist roller pair 18-2. Bring the two rollers into contact.

Further, when the rear end of the paper P passes through 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 paper feed unit outlet roller pair 45 returns to the initial position, and the two rollers are in contact with each other, so that the rear end of the front paper P is before passing through the positions of the relay roller pair 43 and the resist roller pair 18. However, it is possible to receive the next paper 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 resist roller pair 18. The operation of each part when the paper P is conveyed will be described.

[Reference Configuration Example 1]
FIG. 5 is an explanatory diagram of the pre-transfer transfer unit 300 of the first reference configuration example (reference configuration example 1). Further, FIG. 5 shows a case where the paper P longer than the distance of the paper transport path 19 from the paper feed unit outlet roller pair 45 to the resist roller pair 18 is conveyed, and the tip of the paper P is the width direction position detection sensor 46. It is explanatory drawing which shows the operation of each roller pair after passing a detection position.
Reference configuration example 1 does not include the paper feed unit outlet roller pair shift motor 452, and does not have the function of shifting the paper feed unit outlet roller pair 45.
Also in Reference Configuration Example 1, when the transfer timing is adjusted by the resist roller pair 18 and the transfer toward the secondary transfer nip is restarted, the paper P is subjected to the width direction (main scanning direction) by the width direction position detection sensor 46. ) 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 tip of the paper P has passed the detection position of the widthwise position detection sensor 46. In Reference Configuration Example 1, when the tip of the paper P passes the detection position of the width direction position detection sensor 46, the relay roller contact / detachment drive source 431 and the paper feed unit outlet roller contact / detachment motor 451 are driven. By driving the relay roller contact / detachment drive source 431, the relay outer roller 43b is moved in the direction of the arrow “A1” in FIG. 5 (b), and the relay inner roller 43a and the relay outer roller 43b are separated from each other. Further, by driving the paper feed unit outlet roller contact / detachment motor 451 to move the paper feed unit outlet outer roller 45b in the direction of the arrow “A2” in FIG. 5 (b), the paper feed unit outlet inner roller 45a and the paper feed unit outlet inner roller 45a are moved. Separate the outer roller 45b from the paper feed unit outlet.

When the relay roller pair 43 and the paper feed unit outlet roller pair 45 are separated from each other, only the resist roller pair 18 is moved in the width direction by the calculated correction amount, and the positions of the paper P in the width direction are aligned with the paper P. Complete the correction of the transport position. After separating the relay roller pair 43 and the paper feed unit outlet roller pair 45, until the paper P is sandwiched by the secondary transfer nip, as shown in FIG. 5 (c), the paper P is made only by the resist roller pair 18. To transport.

After that, when the paper P is sandwiched between the secondary transfer nips, the resist roller contact / detachment motor 181 is driven. As a result, the resist upper roller 18a is moved away from the resist lower roller 18b, the resist upper roller 18a and the resist lower roller 18b are separated from each other, and the surface moving body (16, 15) forming the secondary transfer nip forms the paper. P is conveyed. When the resist roller pair 18 is separated, the resist roller pair shift motor 182 is driven to return the position of the resist roller pair 18 in the width direction to the initial position which is the position before the shift operation described above. When the position in the width direction of the resist roller pair 18 becomes the initial position and the rear end of the paper P passes the position of the resist roller pair 18, the resist roller pair contact / separation motor 181 is driven to drive the resist roller pair 18-2. Bring the two rollers into contact. When the resist roller pair 18 returns to the initial position and the two rollers are in contact with each other, the next paper P can be fed.

In Reference Configuration Example 1, when the rear end of the paper P to be shifted is on the upstream side of the position of the relay roller pair 43 when the shift operation is performed by the resist roller pair 18, the following control is performed. That is, when the rear end of the paper P does not pass through the position of the roller pair when the shift operation is performed by the roller pair upstream of the resist roller pair 18, the two rollers forming the roller pair are separated from each other. It is configured to be made to. That is, when the rear end of the paper 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 from each other. Further, when shifting, if the rear end of the paper P to be shifted is on the upstream side of the paper feed section outlet roller pair 45 further upstream of the relay roller pair 43, the two paper feed section outlet rollers pair 45 Also separate the rollers.

In the pre-transfer transfer unit 300 of Reference Configuration Example 1, at the stage of performing the shift operation of moving the resist roller pair 18 in the width direction, the roller pair holding the paper P is the resist roller pair 18 regardless of the length of the paper P. Only.
FIG. 6 shows a state in which the paper P guided by the pre-transfer transfer guide 55, which is a transfer path forming member forming the paper transfer path 19 of the pre-transfer transfer unit 300, is shifted by the resist roller pair 18 in Reference Configuration Example 1. It is explanatory drawing which shows schematically. The arrow “B” in FIG. 6 indicates the transport direction of the paper P.

When performing the shift operation, the resist roller pair 18 applies a transport force in the direction of the arrow “B” in FIG. 6 to the paper P, and has a width as shown by the arrow “S” in FIG. 6 (a). Move in the direction. As a result, a force that moves in the width direction together with the resist roller pair 18 acts on the paper P as shown by the arrow “F1” in FIG. On the other hand, since the paper P guided by the pre-transfer transfer guide 55 is in contact with the pre-transfer transfer guide 55, when the sheet P tries to move in the width direction, the paper P is in contact with the pre-transfer transfer guide 55 in FIG. The frictional force as shown by the arrow "F2" of is acting.
The force in the shift direction due to the resist roller pair 18 acts only near the tip of the paper P in the transport direction, and the frictional force with the pre-transfer transfer guide 55 is applied to the portion of the paper P in contact with the pre-transfer transfer guide 55 in the entire transport direction. It works. Therefore, the rotational moment indicated 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 tip of the paper P hits the resist roller pair 18, the skew generated when the paper P is sandwiched between the resist roller pairs 18 and conveyed is not corrected, and the paper is not corrected. P is conveyed to the secondary transfer nip with skew. When the toner image is transferred to the skewed paper P by the secondary transfer nip, there is a possibility that an image defect may occur in which the image is tilted with respect to the paper P.

[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 transfer unit 300 of Reference Configuration Example 2. Further, FIG. 7 shows a case where the paper P longer than the distance of the paper transport path 19 from the paper feed section outlet roller pair 45 to the resist roller pair 18 is conveyed, and the tip of the paper P is the width direction position detection sensor 46. It is explanatory drawing which shows the operation of each roller after passing a detection position.

Unlike the reference configuration example 1, the reference configuration example 2 is provided with the paper feed unit outlet roller vs. shift motor 452, and the paper feed unit outlet roller pair 45 located upstream of the resist roller pair 18 which is the shift roller pair assists. It is a configuration that functions as a shift roller pair. The configuration in which the paper feed unit outlet roller pair 45 functions as the auxiliary shift roller pair is the same as that of the pre-transfer transfer unit 300 of the above-described embodiment. However, Reference Configuration Example 2 is different from the pre-transfer transfer unit 300 of the embodiment in that the paper P is conveyed by the paper feed unit outlet roller pair 45 and the resist roller pair 18 even after the shift operation is completed.

FIG. 7A is an explanatory diagram immediately after the tip of the paper P has passed the detection position of the widthwise position detection sensor 46.
When the tip of the paper P passes the detection position of the width direction position detection sensor 46, the relay roller facing / detaching drive source 431 is driven to move the relay outer roller 43b in the direction of the arrow “A1” in FIG. 7 (b). It is moved to separate the relay inner roller 43a and the relay outer roller 43b. This makes it possible to prevent the relay roller pair 43 located upstream of the resist roller pair 18 from hindering the shift of the paper P when the shift operation is performed using the resist roller pair 18.

After separating the relay inner roller 43a and the relay outer roller 43b, the control unit 50 drives the resist roller vs. shift motor 182 and the paper feed unit outlet roller vs. shift motor 452, and the resist roller pair 18 and the paper feed unit The exit roller vs. 45 is synchronized and shifted.
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 and the shift operation is completed, the resist roller pair 18 and the supply are supplied as shown in FIG. 7 (c). The paper P is conveyed while the paper P is sandwiched between the paper outlet roller pair 45.

In the pre-transfer transfer unit 300 of Reference Configuration Example 2, at the stage of performing the shift operation of moving the resist roller pair 18 in the width direction, the roller pair that holds the paper P when the paper P is long is supplied with the resist roller pair 18. There are two sets of roller pairs, the paper outlet roller pair 45.
FIG. 8 shows, in Reference Configuration Example 2, that the paper P guided by the pre-transfer transfer guide 55, which is a transfer path forming member forming the paper transfer path 19 of the pre-transfer transfer section 300, has a resist roller pair 18 and a paper feed section. It is explanatory drawing which shows typically the state which is shifted by the exit roller pair 45. Similar to FIG. 6, the arrow “B” in FIG. 8 indicates the transport direction of the paper P.

When performing the shift operation, the resist roller pair 18 applies a transport force in the direction of the arrow “B” in FIG. 8 to the paper P, and has a width as shown by the arrow “S1” in FIG. 8 (a). Move in the direction. As a result, a force that moves in the width direction together with the resist roller pair 18 acts on the paper P as shown by the arrow “F1” in FIG. Further, the paper feed unit outlet roller pair 45 applies a transport force in the direction of the arrow “B” in FIG. 8 to the paper P, and is in the width direction as shown by the arrow “S2” in FIG. 8 (a). Move to. As a result, a force that moves in the width direction together with the paper feed unit outlet roller pair 45 acts on the paper P as shown by the arrow “F3” in FIG.
On the other hand, since the paper P guided by the pre-transfer transfer guide 55 is in contact with the pre-transfer transfer guide 55, when the sheet P tries to move in the width direction, the pre-transfer transfer guide is similar to the reference configuration example 1. A frictional force as shown by the arrow “F2” in FIG. 8 acts between the 55 and the 55.

In the reference configuration example 2, the frictional force with the pre-transfer transfer guide 55 acts on the portion of the paper P in contact with the pre-transfer transfer guide 55 over the entire transfer direction, 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 vicinity of the rear end of the paper P in the transport direction by the resist roller pair 18 and the paper feed unit outlet roller pair 45. .. Therefore, it is possible to suppress the action of the rotational moment on the paper P and suppress the occurrence of skew in the shift operation.

However, in the pre-transfer transfer unit 300 of Reference Configuration Example 2, the paper P is shifted between the resist roller pair 18 and the paper feed unit outlet roller pair 45, the position of the paper P in the width direction is adjusted, and after the shift is completed, the paper P is adjusted. Paper P is conveyed by the resist roller pair 18 and the paper feed unit outlet roller pair 45.
Generally, in a roller pair that conveys a sheet such as paper P, the rotation axis of the roller is tilted with respect to the conveying direction due to component error, assembly error, etc., or the two rollers forming the roller pair come into contact with each other. The pressure varies in the axial direction. These affect the passing sheet as a skew component of each roller pair.
In Reference Configuration Example 2, after the shift is completed, the paper P is conveyed by the resist roller pair 18 and the paper feed unit outlet roller pair 45, so that the conveyed paper P is the skew component of the two sets of roller pairs. Due to the influence, the inclination of the paper P with respect to the transport direction may become large.

In the present embodiment, when the paper P shorter than the distance of the paper transport path 19 from the paper feed section outlet roller pair 45 to the resist roller pair 18 is conveyed, only the resist roller pair 18 is shifted in the width direction. On the other hand, when the paper P longer than the distance of the paper transport path 19 from the paper feed unit outlet roller pair 45 to the resist roller pair 18 is conveyed, the paper is conveyed by the resist roller pair 18 and the paper feed unit outlet roller pair 45. With P sandwiched between them, these two sets of rollers are moved in the width direction to perform a shift operation.
Since the paper P is sandwiched between the resist roller pair 18 and the paper feed unit outlet roller pair 45 to shift, the rotational moment acts on the paper P as in the reference configuration example 2 described with reference to FIG. It can be suppressed and the occurrence of skew in the shift operation can be suppressed.

Further, after the shift operation between the resist roller pair 18 and the paper feed unit outlet roller pair 45 is completed, the paper feed unit outlet roller pair 45 separates the rollers from each other, and the paper P is conveyed only by the resist roller pair 18. .. At this time, the two rollers of the paper feed unit outlet roller pair 45 are separated from each other before the rear end of the paper P passes through the position where the paper feed unit outlet roller pair 45 sandwiches the paper P. As a result, it is possible to prevent the paper P from being affected by the skew component (force that tilts the paper P with respect to the transport direction) of the paper feed unit outlet roller pair 45. Therefore, it is possible to suppress an increase in the inclination of the paper P with respect to the transport direction, and it is possible to improve the transport accuracy of the paper P.

Further, by improving the transport accuracy, the accuracy of the position of the paper P at the secondary transfer nip that transfers the toner image to the paper P is improved, and the misalignment of the image when the toner image is transferred to the paper P can be suppressed. It is possible to improve the image accuracy of the image formed on P.

The paper P abuts on the resist roller pair 18 to correct the skew. However, after passing through the resist roller pair 18, it is conveyed by the resist roller pair 18 and the paper feed unit outlet roller pair 45, and is affected by the skew component of these roller pairs.

There are the following methods for correcting the influence of skew after passing through the resist roller pair 18. That is, there is a method of forming a test putter for detecting the influence of skew on paper P, reading this test pattern with a reading means, and forming a corrected image tilted according to the skew based on the read image information.

Attempting to form such a corrected image with the configuration of Reference Configuration Example 2 has the following problems. That is, in Reference Configuration Example 2, since the skew component that tilts the paper P after the shift operation is a plurality of skew components of the resist roller pair 18 skew component and the paper feed unit outlet roller pair 45 skew component, the influence of skew. Is difficult to pattern. Therefore, it is difficult to form a corrected image that is tilted according to the skew of the paper P, and there is a possibility that the tilt of the image with respect to the paper P may be deteriorated.

On the other hand, in the printer 100 of the present embodiment in which the paper P is conveyed only by the resist roller pair 18 after the shift operation, the skew component that tilts the paper P after the shift operation is only the skew component of the resist roller pair 18. Therefore, it is easy to pattern the influence of the skew, it is easy to create a corrected image inclined according to the skew, and it is possible to improve the image quality.

FIG. 9 is a flowchart of the shift operation of the pre-transfer transfer unit 300 of the present embodiment.
When the tip of the paper P fed from the paper feed tray 5 passes the detection position of the resist sensor 21, the resist sensor 21 is turned “ON” (S1). After this "ON", the transfer of the paper P is temporarily stopped at the timing when the tip of the paper P hits the resist roller pair 18, and it is detected whether or not the length of the paper P reaches the paper feed section outlet roller pair 45. (S2). In the present embodiment, when the rear end detection sensor 47 detects the paper P at the timing when the paper P is stopped to be conveyed, the length of the paper P when the tip reaches the resist roller pair 18 is the paper feed 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 conveyed is detected based on the detection result of the sensor arranged 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 on which the paper P has been fed and the size information of the conveyed paper P input from the operation panel 3 or the like. ..

For example, in a printer 100 having a plurality of paper feed trays 5, it is common to separate the paper feed trays 5 for setting the paper P according to the size and orientation of the paper P. Then, 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. Therefore, by taking out the size information in the length direction of the paper P set in the paper feed tray 5 into which the paper P has been fed from the storage unit, the length of the paper P when the tip reaches the resist roller pair 18 However, it can be determined whether or not the length reaches the paper feed unit outlet roller pair 45.

When the length of the paper P reaches the length of the paper feed unit outlet roller pair 45 (“Yes” in S2), the paper feed unit outlet roller pair 45, the relay roller pair 43, and the resist roller pair 18 are rotationally driven. Let me. Then, when the width direction position detection sensor 46 detects the paper P, the relay roller pair 43 is separated (S3), and the rotational drive of the relay roller pair 43 is stopped. After separating the relay roller pair 43, the resist roller pair 18 and the paper feed unit outlet roller pair 45 shift with each other while the resist roller pair 18 and the paper feed unit outlet roller pair 45 are rotationally driven. Do (S4). When the shift operation is completed, the paper feed section outlet roller pair 45 is separated (S5), and while the paper P is being conveyed while the resist roller pair 18 is being rotationally driven, the position of the paper feed section outlet roller pair 45 in the width direction is changed. Return to the initial position (S6). After that, the rear end detection sensor 47 detects the passage of the rear end of the paper P (S7), and after a predetermined time (several milliseconds in this embodiment) has elapsed, the paper feed unit outlet roller pair 45 is brought into contact with the paper P (S8). Accept the next form P (S9).

When the length of the paper P is not long enough to reach the paper feed unit outlet roller pair 45 (“No” in S2), the relay roller pair 43 and the resist roller pair 18 are rotationally driven to drive the width direction position detection sensor 46. When the paper P is detected, the relay roller pair 43 is separated (S10). After that, the shift operation is performed only by the resist roller pair 18 (S11), and the next paper P is accepted (S9).
When the paper P to be conveyed is short, the shift operation is performed only by the resist roller pair 18, so that the paper feed unit outlet roller pair 45 remains in contact with the two rollers at the initial position, and the next paper P is transferred. It will be possible to shorten the time to accept. Therefore, the productivity can be maintained without delay for the next paper feeding operation.

In the pre-transfer transfer unit 300 of Reference Configuration Example 2, after the shift operation is performed between the resist roller pair 18 and the paper feed unit outlet roller pair 45, the rear end of the paper P passes through the paper feed 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.
On the other hand, in the pre-transfer transfer unit 300 of the present embodiment, after the shift operation is performed between the resist roller pair 18 and the paper feed unit outlet roller pair 45, the paper feed unit is immediately fed regardless of the position of the paper P. Separate the outlet rollers vs. 45. Therefore, 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 rear end of the paper P passes through the position sandwiched between the paper feed unit outlet roller pair 45.
Further, the paper feed unit outlet roller pair 45 separated and returned to the initial position has two rollers after a predetermined time (several milliseconds) has elapsed after the paper P being conveyed passes through the detection position of the rear end detection sensor 47. Controls the contact.

As described above, the pre-transfer transfer unit 300 of 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 transfer unit 300 of the reference configuration example 2. be able to. As a result, the time until the next paper P is accepted can be shortened, and the space between the papers can be reduced. Productivity can be maintained without delay for the next paper feed 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 that detects the position in the width direction of the paper P. The widthwise position detection sensor 46 is installed at a position immediately after passing through the resist roller pair 18 in the paper transport path 19. In the width direction position detection sensor 46, a plurality of photosensors including a light emitting element such as an LED and a light receiving element such as a photodiode are arranged side by side in the width direction (vertical direction in FIG. 10). Then, by detecting the position of the paper edge portion PE, which is the widthwise end portion of the paper P, the amount of deviation of the lateral position of the paper P is detected. That is, the width direction position detection sensor 46 detects the amount of misalignment in the width direction of the paper P transported through the paper transport path 19 of the pre-transfer transfer unit 300. Therefore, based on the detection result of the width direction position detection sensor 46, the lateral position correction by the resist roller pair 18 and the paper feed unit outlet roller pair 45 (or the lateral position correction by only the resist roller pair 18) is performed. Will be.

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

FIG. 11 is an explanatory diagram of a relay roller pair contact / disconnection mechanism 30 that connects / detaches the relay roller pair 43. 11 (a) is a perspective explanatory view of the relay roller contact / detachment mechanism 30, and FIG. 11 (b) is a cross-sectional explanatory view.
The relay inner roller 43a is a drive roller, and is rotationally driven by transmitting rotational drive from the relay roller pair drive motor 430 to the relay drive shaft 38.

The relay outer roller 43b is a driven roller, and the relay driven rotating shaft 36 to which the relay outer roller 43b is fixed is rotatably supported by the relay slide bearing member 39. The relay slide bearing member 39 is slidably attached to the housing of the printer 100 body only in the moving direction of the relay outer roller 43b. The relay urging spring 37 is a compression spring that urges the relay slide bearing member 39 toward the relay inner roller 43a.

In the relay roller contact / detachment mechanism 30, when the relay roller contact / detachment drive source 431 is driven, the relay contact / detachment press member 32 protrudes to the right in FIG. 11A and presses the separation force input lever 33. .. The separation force input lever 33 is fixed to the relay separation lever rotation 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 the arrow “D” in FIG. 11 with the relay separation lever rotation shaft 34 as the rotation axis. 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 amount of rotation as the separation force input lever 33.
In FIG. 11B, the separation force input lever 33 located on the front side of the cross section shown in the figure is shown by a broken line for convenience.

As shown in FIG. 11, the relay separation lever 35 has a bent portion on the tip end side, and the relay driven rotation 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 rotation shaft 36 acts, and the relay outer roller 43b resists the urging force of the relay urging spring 37 (FIG. 11). b) Move in the direction of the arrow "E" in the middle to separate from the relay inner roller 43a.

Next, it is explanatory drawing of the paper feed unit outlet drive mechanism 600 which rotates and drives the paper feed unit outlet roller pair 45, and shifts and separates the paper feed unit outlet roller pair 45.
FIG. 12 is an explanatory diagram of the paper feed unit outlet drive mechanism 600. FIG. 12 (a) shows a state in which the paper feed unit outlet inner roller 45a and the paper feed unit outlet outer roller 45b of the paper feed unit outlet roller pair 45 are in contact with each other, and FIG. 12 (b) shows a state in which the paper feed unit outlet outer roller 45b is in contact with each other. Indicates a state in which the roller 45a and the outer roller 45b at the outlet of the paper feed section are separated from each other.

The paper feed unit outlet drive mechanism 600 includes a shift unit 60 that can slide in the width direction (direction orthogonal to the paper surface in FIG. 2) with respect to the printer 100 main body. The shift unit 60 supports the paper feed unit outlet inner roller 45a and the paper feed unit outlet outer roller 45b, the paper feed unit outlet roller contact / detachment motor 451 and the paper feed unit outlet roller pair drive motor 450, and is integrated. It is configured to slide with respect to the main body of the printer 100. Further, the shift unit 60 includes a rack gear portion 69 to which a drive for shifting is input.
When the paper feed unit outlet roller pair shift motor 452 arranged on the printer 100 main body side is driven, the shift drive output gear 68 rotates in the direction of the arrow “G” in FIG. 12 (a). As a result, a 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 (the arrow “H” direction in FIG. 12 (a)).

The paper feed unit outlet inner roller 45a is rotatably supported around the paper feed unit outlet inner roller shaft 64 with respect to the housing of the shift unit 60, and the paper feed unit outlet roller vs. drive motor 450 is driven. Then, it is rotationally driven in the direction in which the paper P is conveyed.
The paper feed unit outlet outer roller 45b is rotatably supported by the contact / detachment holder 61 around the paper feed unit outlet outer roller shaft 63. The contact / detachment holder 61 slides in the direction (vertical direction in FIG. 12) in which the outer roller 45b at the outlet of the paper feed unit is brought into contact with the housing of the shift unit 60 by the guide mechanism provided in the housing of the shift unit 60. It is held possible.

The shift unit 60 includes a contact / detachment compression spring 62 that abuts against the housing of the shift unit 60 and the contact / detachment holder 61 and urges the contact / detachment holder 61 toward the roller 45a inside the paper feed unit outlet. In a state where no other external force is acting on the contact / separation holder 61, the contact / separation holder 61 is urged toward the inner roller 45a at the outlet of the paper feed section by the urging force of the contact / separation compression spring 62. As a result, the paper feed unit outlet outer roller 45b rotatably supported by the contact / detachment holder 61 comes into contact with the paper feed unit outlet inner roller 45a. In a state where the paper feed unit outlet outer roller 45b is in contact with the paper feed unit outlet inner roller 45a, the paper feed unit outlet inner roller 45a is driven to rotate, so that the paper feed unit outlet outer roller 45b is driven to rotate.

The shift unit 60 includes a contact / detachment cam 65 to which the contact / detachment holder 61 abuts. The contact / detachment cam 65 is fixed to the contact / detachment cam rotation shaft 66, and when the contact / detachment cam rotation shaft 66 is rotated by driving the feeding unit outlet roller anti-contact / separation motor 451, the contact / detachment cam 65 is together with the contact / detachment cam rotation shaft 66. The contact / detachment cam 65 also rotates.

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

As described above, the shift unit 60 supports the paper feed section outlet inner roller 45a, the paper feed section outlet outer roller 45b, the paper feed section outlet roller contact / detachment motor 451 and the paper feed section outlet roller pair drive motor 450. However, it is configured to slide integrally with the printer 100 main body. Further, the paper feed unit outlet roller vs. contact / detach motor 451 and the paper feed unit outlet roller vs. drive motor 450 and the paper feed unit outlet roller vs. shift motor 452 can independently perform drive control.
With these configurations, the shift operation can be performed in a state where the inner roller 45a at the outlet of the paper feed unit and the outer roller 45b at the outlet of the paper feed unit are separated from each other.
Further, according to the above-described configuration, the shift operation is performed in a state where the paper feed unit outlet inner roller 45a and the paper feed unit outlet outer roller 45b are in contact with each other and the paper feed unit outlet inner roller 45a is rotationally driven. Can be done. That is, the shift operation can be performed while conveying the paper P in the conveying direction.

[Modification example]
Next, a modified example of the paper feed unit outlet drive mechanism 600 will be described.
FIG. 13 is an explanatory diagram of the paper feed unit outlet drive mechanism 600 of the modified example. FIG. 13 (a) shows a state in which the paper feed section outlet inner roller 45a and the paper feed section outlet outer roller 45b of the paper feed section outlet roller pair 45 are in contact with each other, and FIG. 13 (b) shows a state in which the paper feed section outlet outer roller 45b is in contact with each other. Indicates a state in which the roller 45a and the outer roller 45b at the outlet of the paper feed section are separated from each other.

The paper feed unit outlet drive mechanism 600 of the modified example is the same as the paper feed unit outlet drive mechanism 600 of the embodiment shown in FIG. 12, in the width direction (direction orthogonal to the paper surface in FIG. 2) with respect to the printer 100 main body. A slideable shift unit 60 is provided. The shift unit 60 has a paper feed section outlet inner roller 45a, a paper feed section outlet outer roller 45b, a paper feed section outlet roller contact / detachment motor 451 and a paper feed section outlet roller vs. drive motor 450. A roller contact / detachment mechanism 80 is provided inside. Then, each member constituting the paper feed unit outlet roller contact / detachment mechanism 80 is supported and integrally slides with respect to the printer 100 main body.

Further, the shift unit 60 includes a rack gear portion 69 to which a drive for shifting is input. Then, similarly to the paper feed unit outlet drive mechanism 600 shown in FIG. 13, the paper feed unit outlet roller pair shift motor 452 is driven and the shift drive output gear 68 is rotated, so that the shift unit 60 is moved in the width direction (FIG. 13). (A) Move in the direction of the arrow "H" in the middle.

FIG. 14 is an explanatory diagram of a paper feed unit outlet roller contact / detachment mechanism 80 arranged in the shift unit 60 of the modified example. 14 (a) is a perspective explanatory view of the paper feed unit outlet roller contact / detachment mechanism 80, and FIG. 14 (b) is a cross-sectional explanatory view. 14 (a) and 14 (b) both show a state in which the inner roller 45a at the outlet of the paper feed unit and the outer roller 45b at the outlet of the paper feed unit are in contact with each other.

The paper feed unit outlet inner roller 45a is rotatably supported around the paper feed unit outlet inner roller shaft 64 with respect to the housing of the shift unit 60, and the paper feed unit outlet roller vs. drive motor 450 is driven. Then, it is rotationally driven in the direction in which the paper P is conveyed.
The paper feed unit outlet outer roller 45b is rotatably supported by the contact / separation bearing member 67 about the paper feed unit outlet outer roller shaft 63. The contact / separation bearing member 67 is in a direction (vertical direction in FIG. 13) in which the outer roller 45b at the outlet of the paper feed unit is brought into contact with the housing of the shift unit 60 by a guide mechanism provided in the housing of the shift unit 60. It is held slidable.

The paper feed unit outlet roller contact / detachment mechanism 80 abuts against the housing of the shift unit 60 and the contact / detach bearing member 67, and urges the contact / detach 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 acting on the contact / detachment bearing member 67, the contact / detachment bearing member 67 is urged toward the inner roller 45a at the outlet of the paper feed section by the urging force of the contact / detachment compression spring 62. As a result, the paper feed section outlet outer roller 45b rotatably supported by the contact / detachment bearing member 67 comes into contact with the paper feed section outlet inner roller 45a. In a state where the paper feed unit outlet outer roller 45b is in contact with the paper feed unit outlet inner roller 45a, the paper feed unit outlet inner roller 45a is driven to rotate, so that the paper feed unit outlet outer roller 45b is driven to rotate.

The paper feed unit outlet roller contact / detachment mechanism 80 includes a contact / detachment cam rotation shaft 66 that is rotated by driving the paper feed unit outlet roller contact / detachment motor 451 and a contact / detachment cam 65 that is fixed to the contact / detachment cam rotation shaft 66. To prepare for. Further, the contact / disengagement lever rotating shaft 71 that can rotate with respect to the housing of the shift unit 60, and the contact / disengagement cam pressing lever 70 that is fixed to the contact / disengagement lever rotation shaft 71 and pressed by the contact / disengagement cam 65. It includes a contact / detachment lever 72 fixed to the lever rotation shaft 71.
In FIG. 14B, the contact / detachment cam 65 and the contact / detachment cam pressing lever 70, which are located on the front side of the cross section shown in the figure, are shown by broken lines for convenience.

In a state where the two rollers shown in FIGS. 13A and 14 are in contact with each other, the short side portion of the elliptical contact / detachment cam 65 is in contact with the contact / detachment cam pressing lever 70. When the paper feed unit outlet roller contact / detachment motor 451 is driven from the state shown in FIGS. 13A and 14, the contact / detachment cam rotation shaft 66 and the contact / detachment cam 65 are brought into contact with each other by the arrows in FIGS. 13A and 14; Rotate in the "I" direction. This rotation increases the distance from the center of rotation of the portion of the peripheral surface of the elliptical contact / detachment cam 65 that comes into contact with the contact / detachment cam pressing lever 70, and the contact / detachment cam 65 presses the contact / detachment cam pressing lever 70. Then, the contact / detachment cam pressing lever 70 rotates around the contact / detachment lever rotation shaft 71 in the direction of the arrow “K” in FIGS. 13 (a) and 14. At this time, the contact / detachment lever rotating shaft 71 and the contact / detachment lever 72 rotate together with the contact / detachment cam pressing lever 70 by the same amount of rotation as the contact / detaching cam pressing lever 70.

When the contact / detachment lever 72 rotates in the direction of the arrow “K” in FIGS. 13 (a) and 14, the contact / detachment cam pressing lever 70 contacts the outer roller shaft 63 at the outlet of the paper feed unit and further rotates to supply the paper. A force that pushes up the outer roller shaft 63 at the paper outlet acts. As a result, the outer roller 45b at the outlet of the paper feed section moves in the direction of the arrow “L” in FIGS. 13 (a) and 14 against the urging force of the contact / detachment compression spring 62, and is shown in FIG. 13 (b). As described above, the outer roller 45b at the outlet of the paper feed unit is separated from the inner roller 45a at the outlet of the paper feed unit.

The paper feed unit outlet drive mechanism 600 of the modified example can perform the shift operation in a state where the paper feed unit outlet inner roller 45a and the paper feed unit outlet outer roller 45b are separated from each other, as in the above-described embodiment. Further, the shift operation can be performed while the paper feed unit outlet inner roller 45a and the paper feed unit outlet outer roller 45b are in contact with each other and the paper feed unit outlet inner roller 45a is rotationally driven. That is, the shift operation can be performed while conveying the paper P in the conveying direction.

The resist roller pair 18 is also a shift roller pair in which two rollers can be brought into contact with each other, similar to the paper feed unit outlet roller pair 45. Therefore, as the resist drive mechanism for rotationally driving the resist roller pair 18 to shift and separate it, the paper feed unit outlet drive mechanism 600 of the embodiment shown in FIG. 12 and the paper feed of the modified examples shown in FIGS. 13 and 14. A configuration similar to that of the unit outlet drive mechanism 600 can be used.

In the above-described embodiment, the case where the two sets of shift roller pairs that perform the shift operation with the paper P sandwiched between the resist roller pair 18 and the paper feed unit outlet roller pair 45 has been described, but the present invention is not limited to this. The two sets of shift roller pairs may be a combination of two sets of transport roller pairs, and may be configured such that, for example, the resist roller pair 18 and the relay roller pair 43 sandwich the paper P to perform a shift operation. However, if the distance between the two sets of shift roller pairs in the paper transport path 19 is short, if the paper P is long in the transport direction, the paper P may be skewed during the shift operation, as described with reference to FIG. There is. Therefore, the two sets of transport roller pairs at a position where the paper P is not skewed even if the paper P having the maximum length that can be conveyed is sandwiched between the two sets of shift roller pairs are used as the shift roller pair. Is desirable.

In the above-described embodiment, the shift roller pair in which the pinching and transporting member pair that shifts by sandwiching the sheet between the two pinching and transporting members is formed by the two roller members has been described, but the pinching and transporting member that forms the pinching and transporting member pair is It is not limited to two roller members. For example, the seat may be sandwiched between the belt members, or the seat may be sandwiched between the belt member and the roller member.
Further, the sandwiching and transporting member pair is not limited to a configuration in which both of the two sandwiching and transporting members that sandwich the sheet are surface moving bodies such as a roller member or a belt member. At least one of the two sandwiching and transporting members that sandwich the sheet by applying pressure is a surface moving body, and it may be used as long as it transports the sheet by moving on the surface. For example, two sandwiching and transporting members include a roller member that is a surface moving body and a plate member that does not move on the surface, and by rotating the roller member while sandwiching the sheet, a transporting force is applied to the sandwiched sheet to give the sheet. May be configured to be conveyed while rubbing against the plate member.

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

FIG. 15 is a schematic configuration diagram of a copying machine 500, which is an image forming apparatus including an automatic document transporting apparatus according to a 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 device 400 includes an ADF 8 which is an automatic document transporting device and a scanner 9 which is an image reading means.
The printer 100 included in the copying machine 500 can be formed on the paper P based on the image information input from the input terminal such as a personal computer or the operation panel 3 in the same manner as 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 device 400.
The image scanning device 400 is configured to be switchable between a flatbed scanner mode (placed document scanning mode) and a DF scanner mode (conveyed document scanning mode).

The flatbed scanner mode is executed when a scanning start request operation such as pressing the copy start button is performed while the original is placed on the flatbed contact glass 113 on the upper part of the scanner 9, and the image of the placed original is displayed. This is the operation mode for reading. While moving the image reading unit 116 in the moving reading area 111 directly below the flatbed contact glass 113, the image surface of the original is irradiated with light. Then, the image of the document is read by converting the light reflected from the image surface of the document into an image signal.
The DF scanner mode is an operation mode in which the image reading unit 116 is stopped at the stop reading area 112 directly below the DF contact glass 114 to read the conveyed original image.

In the DF scanner mode, the ADF 8 separates the original sheets one by one from the original sheet bundle loaded on the original placing tray 121 (the original placing table), carries them into the original carrying path 122, and carries them into the original carrying path 122. Transport along. Then, during the transport, the document sheet is sequentially and partially opposed to the upper surface of the DF contact glass 114 from the upstream portion in the transport direction.

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

The image reading unit 116 may be a CCD module, a CIS module, or the like, as long as it can repeatedly scan and read the image on the front surface side of the original at a predetermined image reading position. Further, a fixed image reading unit fixed to the stop reading area 112 and a moving reading unit that moves along the flatbed contact glass 113 in the moving reading area 111 may be provided.

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

The ADF8 is covered with a cover 138 that can be opened and closed at least above it. Further, the main guide portion forming the document transport path 122 of the ADF8 is formed by a rib or the like formed on the cover 138. On the other hand, the ADF 8 has a calling roller 124 that calls the document set on the document mounting tray 121 in the paper feeding direction, and a document for sending the document called in the paper feeding direction by the calling roller 124 toward the document transport path 122. It includes a feed roller 125 and a separation pad 143.

The ADF 8 conveys the originals fed into the original transfer path 122 by the feed roller 125 on the DF contact glass 114 in an image-readable posture, and conveys the originals after image reading to the discharge port 136. I have.

The transport unit 127 reverses the document sheet separated and carried by the feed roller 125 or the like so as to be folded back along the document transport path 122, and passes through a predetermined reading position on the upper surface of the DF contact glass 114. Transport the manuscript sheet. For such document transfer, the first transfer roller pair 128, the second transfer roller pair 129, and the tip of the document sheet in the transfer direction are detected on the upstream side of the document transfer path 122 from the DF contact glass 114. A document registration sensor 131 is provided. Further, on the upstream side of the first transport roller pair 128 of the document transport path 122, an abutting sensor 154 for detecting that the document sheet has passed through the separation nip formed by the feed roller 125 and the separation pad 143 is provided. Has been done.

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

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

For example, when the tip of the document sheet is detected by the document resist sensor 131, the timing at which the tip position of the document sheet that can be detected by the pulse count of the document feeding motor, which is the drive source, reaches the reading position on the DF contact glass 114 is reached. Be identified. A gate signal indicating an effective image area in the sub-scanning direction of the surface of the document sheet begins to be transmitted, and the gate signal continues to be transmitted until the rear end position of the document sheet passes the reading position.

When the back side image of the original sheet is required to be read, the back side image is read by the back side image reading module 135 (second image reading unit) including the close contact type image sensor for back side reading.

The back surface image reading module 135 includes a light source unit that irradiates the original sheet with light based on a lighting signal from the control unit, a plurality of sensor chips that receive the reflected light from the original sheet, and a signal output from each sensor chip. It is provided with a plurality of amplification units for amplifying. The back surface image reading module 135 also includes an A / D conversion unit that converts the signal amplified by the amplification unit from an analog signal to a digital signal, and an image processing unit that performs image processing on the digitally converted signal. ..

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

On the downstream side of the document transport path 122 from the DF contact glass 114, a scanning outlet roller 132 for transporting the image-read document on the front surface side to the back surface image scanning module 135 side is provided. On the downstream side of the reading outlet roller 132, a white guide member 133 facing the back surface image reading module 135 and a document ejection roller 137 located downstream of the back surface image reading module 135 and the white guide member 133 are provided. Each is provided.

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

In the ADF8, the first transfer roller pair 128 and the second transfer roller pair 129 move in the sheet width direction while sandwiching the document sheet, thereby shifting the position of the document sheet in the sheet width direction. be. Further, the document resist sensor 131 that detects the tip of the document sheet in the transport direction is a sensor that can detect the arrival of the document sheet at the detection position and the position in the width direction of the reached document sheet.

When the position of the end portion of the original sheet to be conveyed in the sheet width direction is detected by the original resist sensor 131, the original transfer control unit 7 calculates the correction amount in the width direction of the original sheet. Then, the position of the original sheet in the sheet width direction is corrected by performing a shift operation of moving the first transfer roller pair 128 and the second transfer roller pair 129 in the sheet width direction based on the calculated correction amount.
The misalignment of the original sheet in the sheet width direction is likely to occur when the user places the original sheet on the original placing tray 121. If the configuration is such that the shift operation is performed to correct the positional deviation of the document sheet in the sheet width direction as in the ADF8 of the second embodiment, the user is asked to mount the document sheet on the document loading tray 121. The required accuracy of placing the original sheet can be relaxed.

When the tip of the document sheet passes the detection position of the document resist sensor 131, the document transport control unit 7 controls the feed roller 125 and the separation pad 143 to be separated from each other. As a result, when the shift operation is performed using the first transfer roller pair 128 and the second transfer roller pair 129, the separation nip located upstream of the first transfer roller pair 128 and the second transfer roller pair 129 is the document. It is possible to prevent the seat from being hindered from shifting.

After separating the feed roller 125 and the separation pad 143, the document transfer control unit 7 drives a drive mechanism for shifting the first transfer roller pair 128 and a drive mechanism for shifting the second transfer roller pair 129, respectively. .. As a result, the first transfer roller pair 128 and the second transfer roller pair 129 are shifted in synchronization with the document sheet sandwiched between the first transfer roller pair 128 and the second transfer roller pair 129. When the original 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 for connecting and disconnecting the first transfer roller pair 128 is driven, and the first transfer outer roller 128b and the first transfer roller 128b are driven. Separated from the first transport inner roller 128a. After that, the document sheet is conveyed only by the second transfer roller pair 129.

When the first transport roller pair 128 is separated, a drive mechanism for shifting the first transport roller pair 128 is driven, and the position of the first transport roller pair 128 in the seat width direction is the position before the shift operation described above. Return to the initial position. When the position of the first transport roller pair 128 in the sheet width direction is the initial position and the rear end of the document sheet passes through the position of the first transport roller pair 128, a drive mechanism for connecting and disconnecting the first transport roller pair 128 is provided. Driven to bring the two rollers of the first transfer roller vs. 128 into contact.

In the ADF8, when a document sheet shorter than the distance of the document transfer path 122 from the first transfer roller pair 128 to the second transfer roller pair 129 is conveyed, only the second transfer roller pair 129 is shifted in the sheet width direction. It may be configured to make it.
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 are used. The document sheet is sandwiched and the two sets of rollers are moved in the width direction. Since the original sheet is sandwiched between the first transfer roller pair 128 and the second transfer roller pair 129 to shift, the rotation moment is suppressed from acting on the original sheet during the shift operation, and the original sheet is shifted by the shift operation. It is possible to suppress the occurrence of skew.

Further, after the shift operation between the first transfer roller pair 128 and the second transfer roller pair 129 is completed, the first transfer roller pair 128 separates the rollers from each other, and the document sheet is conveyed only by the second transfer roller pair 129. I do. At this time, the two rollers of the first transport roller pair 128 are separated from each other before the rear end of the document sheet passes through the position sandwiched by the first transport roller pair 128. As a result, it is possible to prevent the original sheet from being affected by the skew component (force that tilts the original sheet with respect to the conveying direction) of the first conveying roller pair 128. Therefore, it is possible to suppress the tilting of the original sheet with respect to the sheet conveying direction, and it is possible to improve the conveying accuracy of the original sheet.

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

The "sheet" transported by the sheet transport device according to the present invention includes paper, coated paper, transparencies, label papers, films, fabrics and the like. Furthermore, the "sheet" is a resin sheet, protective paper on the front and back surfaces, a metal sheet, a metal foil such as copper foil, an electronic circuit board material that has been plated, a special film, a plastic film, a prepreg, and an electronic circuit board. Includes sheets for use. The prepreg is a sheet-like material in which carbon fibers and the like are impregnated with a resin in advance. As an example of prepreg, a fibrous reinforcing material such as carbon fiber or glass cloth is impregnated with a thermosetting resin or the like mixed with additives such as a curing agent and a colorant, and heated or dried to a semi-cured state. Includes sheet-like reinforced plastic molding material.

Further, the sheet transport device according to the present invention is generally applicable to a device for transporting a sheet-shaped member, which is required to prevent skew in which the sheet-shaped member is tilted with respect to the transport direction. .. For example, it can be applied to a processing apparatus for processing a sheet-shaped member.

In addition, the "image forming device" equipped with the configuration of the sheet transport device adheres a developer or ink to a medium such as paper, OHP sheet, thread, fiber, fabric, leather, metal, plastic, glass, wood, or ceramics. Includes a device for forming images. Further, "image formation" includes not only imparting an image having a meaning such as characters and figures to a medium, but also imparting an image having no meaning such as a pattern to the medium.

What has been described above is an example, and has a unique effect in each of the following aspects.

(Aspect 1)
Before transfer, it is equipped with two sets of sandwiching and transporting member pairs such as a paper feed section outlet roller pair 45 and a resist roller pair 18 that can transport paper P and other sheets by sandwiching them and move them in the width direction orthogonal to the transport direction. In a sheet transport device such as a transport unit 300, one sheet is moved in the width direction while being sandwiched between two sets of sandwiching transport members, and after the movement in the width direction, two sets of sandwiching transport members are paired. Two sandwiching and transporting members (a paper feeding section outlet inner roller 45a and a feeding section outlet outer roller 45b) forming an upstream side holding and transporting member pair such as a paper feeding section outlet roller pair 45 located on the upstream side in the transport direction. ) Are separated from each other, and the sheet is conveyed by the downstream side sandwiching and conveying member pair such as the resist roller pair 18 located on the downstream side in the conveying direction among the two sets of sandwiching and conveying member pairs.
According to this, as described in the above-described embodiment, it is possible to prevent the sheet from tilting with respect to the transport direction after the seat is sandwiched between two sets of sandwich and transport member pairs and the position in the width direction is adjusted. This is due to the following reasons.
That is, a pair of sandwiched transport members such as a transport roller pair that sandwiches and transports a sheet between two members generates a force that tilts the sheet being transported with respect to the transport direction due to a component error, an assembly error, or the like. It is common. For this reason, if the sheet is sandwiched between two pairs of sandwiching and transporting members and the shift operation is performed, and then the sheet is transported while the sheet is sandwiched between the two pairs of sandwiching and transporting members, the two sets of sandwiching and transporting members are transported. The force that tilts the seat of the member pair acts on the seat.
In the first aspect, after the shift operation, the upstream side holding transport member pair is separated, and the sheet is conveyed by the downstream side holding transport member pair. Therefore, among the forces that tilt the seats of the two sets of sandwiching and transporting member pairs, the force that tilts the seats of the upstream side sandwiching and transporting member pair can be suppressed from acting on the seats. Therefore, as compared with the configuration in which the sheet is continuously conveyed by the pair of sandwiching and conveying members even after the shift operation, it is possible to suppress the sheet from tilting with respect to the conveying direction.

(Aspect 2)
In aspect 1, after separating the two members of the upstream side holding transport member pair and before passing the position where the rear end of the sheet is sandwiched between the upstream side holding transport member pair, the upstream side holding transport member pair is set to the initial position. It is characterized by starting a return movement.
According to this, as described in the above embodiment, by starting the operation of returning to the initial position before the rear end of the sheet passes, the position in the width direction of the shifted upstream side holding and conveying member pair is set to the initial position. It is possible to start the operation of returning to. Therefore, it is possible to shorten the time until the next sheet is accepted.

(Aspect 3)
In the first or second aspect, the width direction position detecting means such as the width direction position detection sensor 46 for detecting the position in the width direction of the sheet in the vicinity of the pair of the downstream side sandwiching transport member is provided, and is based on the detection result of the width direction position detection means. Therefore, it is characterized in that the amount of movement in the width direction of the pair of sandwiched transport members during the shift operation is calculated.
According to this, as described with respect to the above-described embodiment, the correction amount based on the position of the seat immediately before the shift operation can be calculated, and the position of the seat can be appropriately corrected.

(Aspect 4)
In any of aspects 1 to 3, when sheets longer than the distance of the transport path such as the paper transport path 19 from the upstream side pinch transport member pair to the downstream side pinch transport member pair are transported, two sets are used. With the sandwiching and transporting member pair sandwiching the sheet, the two sets of sandwiching and transporting member pairs are moved in the width direction, and the distance of the transport path from the upstream side sandwiching and transporting member pair to the downstream side sandwiching and transporting member pair is shorter than the above. When the sheet is transported, it is characterized in that only the downstream side sandwiching and transporting member pair is moved in the width direction with the downstream side sandwiching and transporting member pair sandwiching the sheet.
According to this, as described in the above-described embodiment, when the sheet to be transported is short, the upstream side sandwiching and transporting member pair is in a state where the two sandwiching and transporting members are in contact with or close to each other at the initial position, and the following It is possible to shorten the time to accept the seat.

(Aspect 5)
In any of aspects 1 to 4, an upstream side sheet detecting means such as a rear end detection sensor 47 for detecting the presence or absence of a sheet on the upstream side in the transport direction with respect to the upstream side sandwiched transport member pair is provided, and the downstream side seat movement is provided. Based on the detection result of the upstream sheet detecting means at the timing when the sheet reaches the body pair, the length of the sheet to be conveyed is larger than the distance of the transfer path from the upstream side holding transfer member pair to the downstream side holding transfer member pair. It is characterized by judging whether or not it is long.
According to this, as described in the above-described embodiment, it is possible to realize a configuration in which the control of the upstream side holding and transporting member pair is different depending on the length of the sheet.

(Aspect 6)
In any of the aspects 1 to 4, the sheet is conveyed based on the information of the sheet (size information of the paper P, etc.) accommodated by the sheet accommodating portion such as the paper feed tray 5 which is the transfer source of the sheet of the paper feed device 200 or the like. It is characterized in that it is determined whether or not the length of the sheet to be used is longer than the distance of the transport path from the upstream side pinch transport member pair to the downstream side pinch transport member pair.
According to this, as described in the above-described embodiment, it is possible to realize a configuration in which the control of the upstream side holding and transporting member pair is different depending on the length of the sheet.

(Aspect 7)
As a configuration for transporting a sheet in an image forming apparatus such as a printer 100 including an image forming means such as an image forming unit 2, an intermediate transfer belt 16 and a secondary transfer roller 15 for forming an image on a sheet such as paper P to be conveyed. The sheet transporting device according to any one of the first to sixth aspects is provided.
According to this, as described above, it is possible to suppress the misalignment of the image formed on the sheet and improve the image accuracy of the image formed on the sheet.

(Aspect 8)
An automatic document transporting device such as ADF8 that transports a document sheet toward an image reading means such as a scanner 9 that reads an image of a document sheet includes a configuration of the sheet transporting device 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 document sheet between two sets of sandwiching transport member pairs of the first transport roller pair 128 and the second transport roller pair 129. After the adjustment, it is possible to prevent the original sheet from tilting with respect to the transport direction. This makes it possible to improve the transfer accuracy of the original sheet.

(Aspect 9)
As a document transporting means in an image reading device such as an image reading device 400 including a document transporting means for transporting a document sheet and an image reading means such as a scanner 9 for reading an image on the document sheet transported by the document transporting means. The automatic document transfer device such as the ADF8 according to the eighth aspect is provided.
According to this, as described with respect to the second embodiment, it is possible to suppress the positional deviation of the image to be read when reading the image of the original sheet, and it is possible to improve the accuracy of the image information obtained by reading. ..

(Aspect 10)
Aspect 9 is described as an image reading means in an image forming apparatus such as a copying machine 500 including an image reading means and an image forming means such as a printer 100 that forms an image based on the image information read by the image reading means. It is characterized by including an image reading device such as the image reading device 400 of the above.
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.

1 Printer body 2 Image drawing unit 3 Operation panel 4 Paper output tray 5 Paper feed tray 8 ADF
9 Scanner 10 Laser scanning unit 11 Charging device 12 Photoreceptor 13 Developer 14 Primary transfer roller 15 Secondary transfer roller 16 Intermediate transfer belt 16a Secondary transfer facing roller 17 Fixing device 18 Resist roller pair 18a Resist upper roller 18b Resist lower roller 19 Paper transport path 21 Resist sensor 30 Relay roller anti-contact / separation mechanism 32 Relay contact / separation presser 33 Separation force input lever 34 Relay separation lever Rotating shaft 35 Relay separation lever 36 Relay driven rotation shaft 37 Relay urging spring 38 Relay drive shaft 39 Relay slide bearing member 40 Branch claw 41 Reversing roller pair 42 Double-sided roller pair 43 Relay roller pair 43a Relay inner roller 43b Relay outer roller 45 Paper feed section outlet roller pair 45a Paper feed section outlet inner roller 45b Paper feed section outlet outer roller 46 Width Directional position detection sensor 47 Rear end detection sensor 50 Control unit 51 Paper feed roller 52 Separation transfer roller 53 Reverse roller 55 Pre-transfer transfer guide 60 Shift unit 61 Contact / separation holder 62 Contact / separation compression spring 63 Paper feed section outlet Outer roller shaft 64 Paper outlet Inner roller shaft 65 Contact / detachment cam 66 Contact / separation cam Rotating shaft 67 Contact / separation bearing member 68 Shift drive output gear 69 Rack gear part 70 Contact / separation cam pressing lever 71 Contact / separation lever Rotating shaft 72 Contact / separation lever 80 Paper feed section outlet Roller anti-contact / separation mechanism 100 Printer 111 Moving reading area 112 Stop reading area 113 Flatbed contact glass 114 Contact glass 116 Image reading unit 121 Document loading tray 122 Document transport path 123 Side guide plate 124 Calling roller 125 Feed roller 127 Transport unit 128 1st transfer roller pair 128a 1st transfer inner roller 128b 1st transfer outer roller 129 2nd transfer roller pair 131 Document registration sensor 132 Reading outlet roller 133 White guide member 135 Back side image reading module 136 Outlet 137 Document ejection roller 138 Cover 139 Original Paper Discharge Tray 143 Separation Pad 180 Resist Roller vs. Drive Motor 181 Resist Roller vs. Contact / Detachment Motor 182 Resist Roller vs. Shift Motor 200 Paper Feed Device 300 Pre-Transfer Transfer Unit 400 Image Reader 430 Relay Roller vs. Drive Motor 431 Relay Roller Pair Contact / separation drive source 450 Paper feed section outlet roller vs. drive motor 451 Paper feed section outlet roller vs. contact / separation motor 452 Paper feed section outlet roller vs. shift motor 600 Paper feed section outlet drive mechanism P paper PE paper edge

Patent No. 6010861

Claims (9)

In a sheet transport device provided with two sets of sandwich transport member pairs capable of transporting by sandwiching a sheet and moving in a width direction orthogonal to the transport direction.
The sheet is moved in the width direction while being sandwiched between two pairs of sandwiching and transporting members.
After the movement in the width direction, the two sets of the pinching and transporting members forming the upstream side pinching and transporting member pair located on the upstream side of the sandwiching and transporting member pair are separated from each other. The sheet is transported by the downstream side pinching and transporting member pair located on the downstream side in the transporting direction among the pinching and transporting member pairs.
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 side sandwiching transport member pair is provided.
Based on the detection result of the upstream sheet detecting means at the timing when the sheet reaches the downstream side sandwiching and transporting member pair, the length of the sheet to be transported is set from the upstream side sandwiching and transporting member pair to the downstream side sandwiching. Determine if it is longer than the distance of the transport path to the transport member pair ,
When the length of the sheet to be transported is longer than the distance of the transport path from the upstream side pinch transport member pair to the downstream side pinch transport member pair, the upstream side pinch transport member pair is separated, but the transport is performed. When the length of the sheet is shorter than the distance of the transport path from the upstream side pinch transport member pair to the downstream side pinch transport member pair, the sheet transport is characterized in that the upstream side pinch transport member pair is not separated. Device. In a sheet transport device provided with two sets of sandwich transport member pairs capable of transporting by sandwiching a sheet and moving in a width direction orthogonal to the transport direction.
The sheet is moved in the width direction while being sandwiched between two pairs of sandwiching and transporting members.
After the movement in the width direction, the two sets of the pinching and transporting members forming the upstream side pinching and transporting member pair located on the upstream side of the sandwiching and transporting member pair are separated from each other. The sheet is transported by the downstream side pinching and transporting member pair located on the downstream side in the transporting direction among the pinching and transporting member pairs.
Based on the information of the sheet accommodated by the sheet accommodating portion of the sheet transport source, the length of the sheet to be transported is the distance of the transport path from the upstream side pinching transport member pair to the downstream side pinching transport member pair. Determine if it is longer than
When the length of the sheet to be conveyed is longer than the distance of the transport path from the upstream side pinch transport member pair to the downstream side pinch transport member pair, the two pinch transport members of the upstream side pinch transport member pair are used. When the length of the sheet to be transported is shorter than the distance of the transport path from the upstream side pinching transport member pair to the downstream side pinching transport member pair, the two said ones of the upstream side pinching transport member pair. A sheet transfer device characterized in that the sandwiching transfer member is not separated . In the sheet transport device of claim 1 or 2,
After separating the two sandwiching and transporting members of the upstream sandwiching and transporting member pair, and before passing the position where the rear end of the sheet is sandwiched between the upstream sandwiching and transporting member pair, the upstream sandwiching and transporting member pair A sheet transport device characterized in that an operation of returning a position in the width direction to an initial position is started. In the sheet transporting apparatus according to any one of claims 1 to 3,
A width direction position detecting means for detecting the position of the sheet in the width direction in the vicinity of the pair of holding and transporting members on the downstream side is provided.
A sheet transfer device characterized in that the amount of movement of two sets of the sandwiched transfer member pairs at the time of movement in the width direction is calculated based on the detection result of the width direction position detecting means. In the sheet transporting apparatus according to any one of claims 1 to 4,
When the sheet is transported longer than the distance of the transport path from the upstream side pinching transport member pair to the downstream side pinching transport member pair, two sets of the pinching transport member pair sandwich the sheet. , The two sets of the sandwiching and transporting member pairs are moved in the width direction.
When the sheet is transported, which is shorter than the distance of the transport path from the upstream side pinching transport member pair to the downstream side pinching transport member pair, the downstream side pinching transport member pair sandwiches the sheet. A sheet transport device characterized in that only the pair of sandwiched transport members on the downstream side is moved in the width direction. In an image forming apparatus provided with an image forming means for forming an image on a conveyed sheet,
An image forming apparatus comprising the configuration of the sheet transporting apparatus according to any one of claims 1 to 5, as a configuration for transporting the sheet. In an automatic document transporting device that transports a document sheet toward an image reading means that reads an image of the document sheet.
An automatic document transporting apparatus comprising the configuration of the sheet transporting apparatus according to any one of claims 1 to 5. A document transporting means for transporting a document sheet and
In an image reading device provided with an image reading means for reading an image on a document sheet conveyed by the document conveying means.
An image reading device comprising the automatic document transporting device according to claim 7 as the document transporting means. Image reading means and
In an image forming apparatus including an image forming means for forming an image based on the image information read by the image reading means.
An image forming apparatus comprising the image reading apparatus according to claim 8 as the image reading means.

Images