JPH05193788A - Paper sheet conveyance correcting device - Google Patents

Abstract

PURPOSE:To perform reasonable correction of the position of a paper sheet during its conveyance by moving at least two sets of roller pair, adjoining to each other, in a direction perpendicular to a paper sheet conveying direction, in a paper sheet conveyance correcting device used in an image forming device, etc. CONSTITUTION:Register rollers 2a and 2b and conveyance rollers 3a and 3b are held in suck a manner as interlocking with a frame 1. The frame 1 is provided with a rack part 14, which is geared with the gear of a motor 9. The reference displacement of a paper sheet 19 is detected by arranging sensors 10a and 10b on downstream side of the conveyance rollers 3a and 3b, the motor 9 is run by means of a signal from a motor control circuit so as to correct the position of the paper sheet 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveyance correcting apparatus used in a laser beam printer or a copying machine, and more specifically, a sheet conveyed by moving a pair of rollers in a direction perpendicular to the sheet conveying direction. The position of the sheet is corrected in the direction perpendicular to the conveying direction.

[0002]

2. Description of the Related Art Conventionally, in a sheet conveyance correcting apparatus capable of moving a pair of conveyance rollers in a direction perpendicular to a sheet conveyance direction,
Only one pair of rollers can be moved. For example, a sheet conveying roller capable of moving a roller called a registration roller (hereinafter referred to as a registration roller) that functions to align the leading ends of sheets in a direction perpendicular to the sheet conveying direction. A correction device is known, in which a sheet conveyed by an upstream conveying roller pair is held by a movable registration roller pair, and a sheet is interposed between the registration roller pair and the conveying roller pair. In the state in which the bending is formed, the registration roller is moved in the direction perpendicular to the sheet to correct the position in the direction perpendicular to the sheet conveying direction.

[0003]

However, in the above-described conventional sheet conveyance correcting apparatus, the deflection is absorbed by forming the deflection of the sheet between the immovable roller pair and the movable roller pair. Even though the roller could be moved up to that point, the range of movement of the roller inevitably became smaller, and if one wanted to increase the range of movement, it would be necessary to increase the deflection, which would force the sheet to be unreasonable. May damage the seat,
There was a drawback that normal transportation could not be performed.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve the above-mentioned conventional problems and to provide a sheet conveyance correcting apparatus capable of correcting the sheet conveying position without applying an excessive force to the sheet.

It is another object of the present invention to provide a sheet conveyance correcting device capable of correcting the conveyance position of a sheet during the conveyance operation without holding the sheet once.

[0006]

In order to achieve this object, the sheet conveyance correcting apparatus of the present invention is configured so that at least two pairs of adjacent rollers can be moved in a direction perpendicular to the sheet conveyance direction. .. Further, at least the roller pair on the upstream side of the roller pair movable in the right angle direction is configured to be intermittently driven.

[0007]

The sheet conveying correction device of the present invention holds a sheet by at least two adjacent roller pairs among the roller pairs in the sheet conveying path, and in that state, these roller pairs are simultaneously moved in the sheet conveying direction. Since it is movable in the right-angled direction, the misalignment of the sheet in the right-angled direction can be corrected without applying an excessive force to the sheet, and the correction can be performed during the conveying operation without holding the sheet once. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sheet conveyance correcting apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an essential part of a sheet conveyance correcting apparatus of the present invention, and FIG. 2 is a side view showing an example of a laser beam printer (hereinafter, LBP) using the sheet conveying correcting apparatus.

In FIG. 2, the LBP main body 16 is provided with two paper feed cassettes 17 and 18, and papers 19 and 2 are respectively provided.
0 is loaded. When the print signal is issued, the stacked sheets 19 or 20 are conveyed to the pair of conveying rollers 23 by the sheet feeding roller 21 or the sheet feeding roller 22. Hereinafter, the printing operation using the paper 19 will be described.

When the paper 19 is further conveyed by the conveying roller pair 23, it reaches the sensor 24, and the sensor 2
After 4 is turned on, the registration roller pair 25 is stopped until a certain timing, and the skew of the sheet 19 is corrected. The sensor 24 also serves to synchronize the image data emitted from the laser unit 26 with the paper 19. The image data printed on the sheet 19 is performed by the well-known Carlson process, and the image data printed on the sheet 19 is fixed by the fixing unit 27.

In the case of a face-down sheet discharge request for single-sided printing, the sheet 19 passes through a pair of conveying rollers 28, a conveying path 29,
After passing through 31, the sheet is discharged onto a sheet discharge tray 33 by a pair of sheet discharge rollers 32.

In the case of a face-up discharge request for single-sided printing, the sheet 19 passes through the sensor 34 located on the upstream side of the conveying roller pair 28, and at the same time the sheet 19 passes through the gate 35.
Is rotated by a solenoid (not shown) and the paper 19 is guided in the direction of the reversing roller pair 11 and discharged onto the paper discharge tray 36.

In the case of a request for double-sided printing, the same is true up to the face-up discharge of the single-sided printing and the point where the paper 19 is guided to the reversing roller pair 11, but the sensor 37 located upstream of the reversing roller pair 11. After the trailing edge of the sheet 19 has passed through, the reversing roller pair 11 is rotated in the clockwise direction by the operation of the drive switching means (not shown) at a certain timing, and the sheet 19 moves toward the transport path 38. Is led. Since the sheet 19 passes through a long-distance transport path and therefore has skew and off-center, it is necessary to correct the printing positions on the front surface and the back surface to match each other. Therefore,
After carrying out the carrying correction by the carrying correction device according to the present invention described later, the carrying is carried to the carrying roller pair 23. The subsequent printing process is the same as described above, and will be omitted here.

Here, the conveyance correcting apparatus according to the present invention will be described in detail with reference to FIG. The registration roller pair 2 and the conveying roller pair 3 are rotatably held on the frame 1 by a bearing 7 and a spring 12, respectively, and the rotational driving of the conveying roller pair 3 is connected by a gear or the like from a drive source (not shown). Is configured. The drive of the registration roller pair 2 is transmitted to the pulley of the clutch 4 attached to the registration roller 2a by the pulley 5 and the belt 6 attached to the conveyance roller 3a. Therefore, the registration roller pair 2 can be intermittently driven by electrically turning on and off the clutch 4.

The frame 1 is provided with a rack portion 14, which is connected to the gear of the motor 9,
When the motor 9 rotates clockwise, the registration roller pair 2 and the conveying roller pair 3 move together with the frame 1 in the direction of arrow a, and when the motor 9 rotates counterclockwise, the arrow b.
Move in the direction of.

The sheet 19 conveyed from the reversing roller pair 11 passes through the sensor 13 and then comes into contact with the registration roller pair 2 whose driving is stopped by the clutch 4 so that skew is not corrected. Then, the registration circuit pair 2 starts rotating when the timer circuit timed by the sensor 13 turns on the clutch 4, and the sheet 19 is conveyed to the conveyance roller pair 3 on the downstream side and reaches the sensor pair 10. At this time, the trailing edge of the sheet 19 is separated from the reversing roller pair 11, and is held by the registration roller pair 2 and the conveying roller pair 3. The sensor pair 10 is set in advance so that the print reference positions of the front surface printing and the back surface printing match, and in the present embodiment, one sensor pair 10 is configured by a combination of the LED and the phototransistor. When the end surface of the paper 19 blocks the light of the LED of the sensor pair 10, the motor 9 is controlled by the motor control circuit until the light starts to be transmitted.
Is rotated to correct the paper position, and when the end surface of the paper 19 transmits the light of the LED of the sensor 10, the motor 9 is rotated to a position where light blocking is started to correct the paper position.
That is, the entire sheet is moved in the direction perpendicular to the conveyance direction to correct the conveyance position. When it is detected by the sensor pair 10 that the trailing edge of the corrected sheet 19 has passed, the motor control circuit drives the motor 19 in accordance with the positional relationship between the photo sensor 8 and the actuator section 15 in which a part of the frame 1 is bent. Rotate 9 clockwise or counterclockwise to make the frame 1 stand by at the home position.

Although the sheet conveyance correcting apparatus of the present embodiment corrects the sheet position during the conveying operation, the sheet position is corrected while the sheet is stopped by using the clutch for the conveying roller pair 3. It is also possible.

Although the sheet conveyance correction in double-sided printing has been described in this embodiment, it is also effective to implement the sheet conveyance correction apparatus of the present invention in the conveyance path up to print transfer in single-sided printing.

[0020]

As described above, according to the present invention, at least two roller pairs adjacent to each other in the conveying rollers are configured to be movable in the direction perpendicular to the sheet conveying direction. The misalignment in the right angle direction can be corrected without any addition, and the position can be corrected during the sheet conveying operation without holding the sheet once, so that the sheet conveying correction can be performed efficiently.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of an example of a sheet conveyance correction device according to the present invention.

FIG. 2 is a cross-sectional view showing an example of a laser beam printer equipped with a sheet conveyance correction device according to the present invention.

[Explanation of symbols]

 1 frame 2 registration roller pair 3 transport roller pair 4 clutch 8 sensor 9 motor 10 sensor pair

Claims (2)

[Claims] 1. A roller pair that conveys a sheet in a predetermined direction is movable in a direction perpendicular to the sheet conveying direction while holding the sheet by at least two adjacent roller pairs. Sheet transport correction device. 2. The sheet conveyance correction device according to claim 1, wherein at least the roller pair on the upstream side of the roller pair movable in the perpendicular direction can be intermittently driven.