JPS6160008B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a device for correcting document skew in a document conveying device of a copying machine.

BACKGROUND ART Conventionally, as a means for conveying a document, it is common to convey the document on a buffer using the nipping force of a conveyance roller and an idler.

FIG. 1 is a schematic plan view and front view of a general document conveying device.

In the figure, reference numeral 1 denotes a buttful, in which a plurality of conveying rollers 2 are provided in a groove provided in the buttful 1 at intervals in the width direction of the buttful, and one row of rollers is arranged in several rows in the longitudinal direction of the buttful. , an idler 3 is pressed against each conveyance roller 2 in a corresponding manner.

Therefore, the document 4 is guided by the buffer 1 and is conveyed between the conveyance roller 2 and the idler 3.

However, as the document is transported through the roller rows in this way, it is unavoidable that skew will occur in the document due to subtle differences between the transport rollers and other various conditions. The more the document is skewed, the greater the skew of the manuscript becomes.

Furthermore, when an operator inserts a document into the conveyance system, the document may be inserted in an inclined state, and in this case, the document is conveyed in an inclined state.

Conventionally, a document guide 5 (see FIG. 1) is provided at one end of the conveyance path to correct the skew of the document by aligning the document along the document guide 5.

However, when the document is skewed, the corner of the document that first contacts the document guide may be crushed or damaged, and if the document is soft, the document may curl, making the effect less effective. There were some drawbacks, such as not having one.

Furthermore, if the center of the document being transported needs to be kept at a constant position regardless of the size of the document, the position of the document guide must be changed each time according to the size of the document, and a special device must be provided for this purpose. is difficult due to cost and mechanical constraints.

OBJECTS OF THE INVENTION The present invention relates to the invention of a document conveying device for a copying machine that overcomes the above-mentioned drawbacks, and its objectives are to:
By gradually decreasing the outer diameter of the roller row in the middle of the document transport path from the center to the left and right periphery, and using either the left or right roller for the document, it is possible to correct skew by applying rotational force to the document. The purpose of the present invention is to provide a document conveying device that can perform the following tasks.

Configuration of the Invention The configuration of the present invention will be explained based on FIG. 2. In a document conveyance device of a copying machine, A denotes a plurality of document conveyance rollers that are arranged in a direction perpendicular to the direction in which the document is conveyed and whose outer diameters are gradually reduced from the center toward the left and right peripheries.

Reference numeral B designates an idler that comes into contact with the document transport roller A in the center.

Reference numeral C denotes left and right idlers which are arranged from the center to the periphery and can come into contact with and separate from the document transport roller A.

Reference numeral D denotes a contacting/separating means for bringing the left and right idlers C into contact with and separating from the document conveying roller A independently.

Reference numeral E denotes a skew angle detecting means for detecting the so-called skew angle of document skew feeding.

F is a control means that calculates the contact time of the left and right idlers C with the document conveyance roller A from the skew angle detected by the skew angle detection means E, and causes the approach and separation means D to be in contact for the same time.

Then, the control means F confirms whether the leading side of the document due to skew is the left side or the right side from the detection signal of the skew angle detecting means E, and the idler C of the leading side
is controlled so that it is brought into contact with the document transport roller A for the calculated time.

Therefore, since the document passing between the document conveying roller A and the idlers B and C that are in contact with each other can be rotated while being conveyed, it is possible to correct the skew of the document.

Embodiments Hereinafter, embodiments of the present invention illustrated in FIGS. 3 to 6 will be described.

FIG. 3 is a schematic plan view and front view of a skew correction device provided during conveyance of a document.

In the figure, the document 10 is being conveyed rightward on the baffle 11, and is in a skewed state with its left end leading in the direction of travel.

In this state, the original is transported by five transport rollers 12 having the same shape and five idlers 13 that are in pressure contact with each transport roller, and this roller row consisting of these rollers simply transports the original. It is intended to carry out only

The roller row next to this roller row corrects the skew while conveying, and the central conveying roller 1
Conveying roller 1 whose outer diameter is set to the maximum outer diameter of 4 and whose outer diameter gradually decreases as it approaches the edge of the buttful.
5 and 16 are arranged symmetrically about the central conveyance roller 14 (see FIG. 4).

The idlers 17, 18, 19 corresponding to each of these conveyance rollers 14, 15, 16 are also formed to have smaller outer diameters in stages from the center to the left and right peripheral directions.
The mutual outer diameter ratio is equal to the mutual outer diameter ratio of the corresponding conveyance rollers.

When the document is not being sent, only the idler 17 corresponding to the central transport roller 14 is connected to the idler 17 corresponding to each transport roller.
The idlers 18 and 19, which correspond to the other conveyance rollers 15 and 16, are separated from each other.

The distance between this skew correction roller row and the front and rear roller rows is such that immediately after the leading edge of the document is sandwiched between the central conveyance roller 14 and idler 17 of the skew correction roller row, the front roller row releases the trailing edge of the document. (In this embodiment, the document size is assumed to be constant).

Further, the roller row next to the skew correction roller row is the same as the previous roller row, and the same transport roller 2 as the transport roller 12 and the idler 13 is used.
0 and an idler 21, and the distance between it and the skew correction roller row needs to be a sufficient distance to correct the skew.

Immediately in front of the skew correction roller row, reflective photo sensors 22 and 23 are arranged, one each on the left and right in the direction of conveyance of the document, for detecting passage of the document.

Therefore, when a document is skewed, there is a difference in the time at which the left and right sensors 22 and 23 detect the document, and the skewed state of the document can be detected based on this time difference.

FIG. 4 is a diagram showing a skew correction mechanism in a roller row for skew correction.

As described above, the outer diameters of the conveying rollers 14, 15, and 16 gradually decrease from the center toward the periphery, and the outer circumferential surfaces have the shape of a conical section cut out parallel to the bottom surface.

These conveyance rollers are integrally attached to a common central shaft 24, which is rotated by a motor (not shown) via pulleys 25 also integrally attached to both ends and a belt (not shown). move.

Therefore, the conveyance rollers 14, 15, and 16 are all rotated at the same rotational speed.

Idler 17 corresponding to the central conveyance roller 14
The position of the central shaft 26 is fixed in a state in which it is in pressure contact with the roller 14, and both ends of the central shaft 26 are engaged with the central shafts 28 of the other idlers 18 and 19 by constant velocity universal joints 27. There is.

The idlers 18 and 19 are integrally attached to this central shaft 28, and one end of the central shaft 28 is the constant velocity universal joint 27, while the other end is also a bearing that can move up and down freely by the constant velocity universal joint 29. It is connected to a rotating outer ring of 30.

The bearing 30 is housed in a rectangular parallelepiped tube and is pulled upwardly by a spring 32, and downwardly attracted by a solenoid 33 against the tension of the spring 32. .

Therefore, when the solenoid 33 is in the OFF state and is pulled by the spring 32 and the bearing 30 is in the upper position, the idlers 18 and 19 are separated from the transport rollers 15 and 16 and do not play the role of transporting the original. When the solenoid 33 is in the ON state and the bearing 30 is sucked downward, the idlers 18 and 19 come into pressure contact with the transport rollers 15 and 16 to transport the original.

The outer diameter of the conveyance roller that is pressed at this time becomes smaller as it goes from the center to the edge, and since the rotational speed is the same, the circumferential speed is different, so the conveyance speed of the document is slower as it gets closer to the edge. As a result,
Rotate the original.

The rotation of the document is performed in such a manner that the edges of the document are delayed since the central conveyance roller with the largest outer diameter provides the normal document conveyance speed.

Therefore, it can be assumed that the widthwise position of the part of the document that has passed over the central transport roller 14 does not change, and if the center of the document is aligned with the center of the insertion slot when inserting the document, the center of the document will remain at the same position even after skew correction. can be kept.

Now the rotation speed of the conveyance roller is ω (rad/sec),
If the outer radius of the transport roller (standard size) in the roller row other than skew correction is r ₁ (mm), then the roller with the maximum outer diameter at the center of the skew correction roller row is standard size, so its outer radius is r ₁ (mm). ), and the conveyance speed of the document is r ₁ ω (mm/sec).

The distance between adjacent transport rollers in the roller row is constant l (mm), and the outer radius of the roller 15 adjacent to the center roller 14 in the skew correction roller row is r ₂
(mm), the circumferential speed of the roller 15 is r ₂ ω
(mm/sec), and the peripheral speed of the central roller is r ₁ ω
(mm/sec), so the skew correction roller row has an angle of r ₁ ω-r ₂ ω/l = (r ₁ - r ₂ ) ω/l (rad/sec) ...(1) Has skew correction ability.

Further, the skew state of the document is detected by the photo sensors 22 and 23.

If the document is being conveyed in a skewed state, there will be a lag in the time at which both sensors detect the leading edge of the document.If the lag time is T (sec) and the distance between both sensors is L (mm), then the document The conveyance speed of is r ₁ ω (mm/sec), so the original is tan ^- ₁ r ₁ ω×T/L=tan ^-1 r ₁ ωT/L (red) in the direction perpendicular to the conveying direction. (
2) It means that it is being transported with an inclination of .

Therefore, in order to correct the skew of this original, from equation (1) above, t=tan ^-1 r ₁ ωT/L/(r ₁ - r ₂ ) ω/l=l/(r ₁ - r ₂ ) It is necessary to perform correction using the skew correction roller array for a time corresponding to ωtan ^-1 r ₁ ωT/L (sec) (3).

In equation (3), r ₁ , r ₂ , l, and L are constant, and if the angular velocity ω of the conveyance roller is also fixed, l/(r ₁ − r ₂ )ω and r ₁ ω/L can be calculated in advance. Then, the correction time t can be easily calculated by measuring the deviation time T of document detection.

In reality, when either the left or right solenoid is activated and the idler on the same side is pressed against the conveyance roller, the solenoid is turned off t hours after the document arrives to release the pressure on the idler, thereby reducing the skew for t time. Corrections will be made.

These controls are performed by a computer, and the operating procedure will be explained based on the flowchart shown in FIG.

First, it starts with document detection by either the left sensor (the left and right instructions are relative to the transport direction) or the right sensor, the left sensor detects the document first, and then turns on.
When this happens, the computer's built-in timer starts, activates the left solenoid, presses the left idler against the corresponding conveyance roller, and waits for the right sensor to detect the document. When the same sensor on the right detects a document, the timer is stopped and the detection time difference between both sensors is T.
Determine.

Also, when the right sensor detects the document first, it also starts the timer and turns on the right solenoid.
Then, wait for the left sensor to detect the document, and when the document is detected, stop the timer and determine the deviation time T.

In this way, when the skew time T is determined with the idler on the side that detected the leading edge of the document first being pressed against the conveyance roller, the skew correction time t is calculated using equation (3) above. Then, determine the approximate time α for the original to arrive at the skew correction roller row after both sensors detect the original, start the timer after the same time α has elapsed, and assume that the correction starts from this point. There isn't that much of an error.

After the correction starts, the calculated time t is measured using a timer, and after the elapse of t, the timer is stopped, the solenoid that was on is turned off, the idler that was in pressure contact is released from the conveyance roller, and the correction is completed. .

In the above embodiment, the document size is constant, and the distance between the skew correction roller row and the preceding roller row is set such that the front roller row releases the trailing edge of the document when skew correction of the document begins. An example that can be applied to various document sizes will be described below.

The second embodiment is the same as the first embodiment except that the roller row preceding the skew correction roller row is provided with a mechanism for releasing the document.

The document release mechanism of the front roller row is illustrated in FIG.

In the figure, the lower stage roller is the conveyance roller 40, and the upper stage is the idler 41.

Both ends of the central shaft 42 of the idler 41 are fixed to the inner ring of a bearing 43, so that the idler 41 can freely rotate.

The outer ring of the bearing 43 is constantly pulled downward by a spring 44, and is moved upward by the drive of a solenoid 45.

Therefore, when the left and right solenoids 45 are turned on, the bearing 43 is pulled upward against the tension of the spring 44, and at the same time the idler 41 moves upward, thereby releasing the pressure contact with the conveying roller 40.

Therefore, the distance between the roller row and the skew correction roller row is narrowed so that the smallest size document is applied to both roller rows at the same time, and even the largest size document is not placed on the three adjacent roller rows. If you set this to , you can apply it to documents of various sizes.

In other words, during correction in the skew correction roller row, the center roller 14 is replaced by the roller 1 on the edge side.
6 has a slower circumferential speed, curling occurs on the side where the roller 16 is in pressure contact with the front roller row that pinches the trailing edge of the document.

After the correction is completed, the solenoid 33 is
Immediately before the timer is turned off, that is, immediately after the timer stops after time t in the flowchart shown in Figure 5, the solenoid 45 in the front roller row is turned on for a short time to release the original, and the curled original is restored. Immediately after that, the solenoid 33 is turned OFF to complete the correction.

In this way, skew correction can be performed regardless of the document size.

Effects of the Invention As described above, according to the present invention, the skew correction of the original can be reliably performed without causing damage to the original and even when the quality of the original is soft.

Furthermore, by aligning the center of the document with the center of the insertion slot when inserting the document, the center of the document can be maintained at a constant position even after skew correction, regardless of the document size.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory plan view and front view of a conventional document conveying device, FIG. 2 is a view corresponding to the claims of the present invention, and FIG. 3 is a schematic explanatory plan view and front view of a first embodiment of the present invention. FIG. 4 is a diagram showing the skew correction mechanism of the first embodiment, FIG. 5 is a flowchart showing the operating procedure in the first embodiment, and FIG. 6 is a front roller row of the skew correction roller row in the second embodiment. FIG. 1... Bumpful, 2... Conveyance roller, 3... Idler, 4... Original, 5... Original guide, 10...
...Original, 11...Bulky, 12...Previous conveyance roller, 13...Idler, 14...Conveyance roller (standard size), 15...Conveyance roller (medium size), 16...Conveyance roller (small size), 17,1
8, 19... Idler, 20... Later conveyance roller, 21... Idler, 22, 23... Reflective photo sensor, 24... Roller center axis, 25... Pulley, 26... Idler center axis, 27... Universal joint, 28...Idler center shaft, 29...Universal joint, 30...Bearing, 31...Cylinder, 32...
Spring, 33...Solenoid, 40...Previous conveyance roller, 41...Idler, 42...Idler center shaft, 43...Bearing, 44...Spring, 45...
…solenoid.

Claims (1)

[Claims] 1. In a document conveyance device of a copying machine, a plurality of document conveyance rollers arranged in a direction perpendicular to the document conveyance direction and whose outer diameters are gradually reduced from the center toward the left and right peripheries come into contact with the central document conveyance roller. a left and right idler that is arranged from the center to the periphery and can come into contact with and separate from the document transport roller; a means for bringing the left and right idlers into contact with and away from the document transport roller independently on the left and right; and a document diagonal feed (hereinafter referred to as a skew angle detection means for detecting the skew angle of the document transport roller (referred to as a skew), and a contact time of the idler with the document conveying roller calculated from the skew angle detected by the skew angle detection means, and the contacting and separating means for the same time. The control means corrects the skew of the document passing between them by bringing the idler on the preceding side of the document into contact with the document conveying roller for the calculated time due to the skew. Feed correction device.