JPH1159972A - Medium bias feeding detecting method and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent erroneous detection of bias feeding due to production error or assembly error and to facilitate assembling work. SOLUTION: A first sensor 27 and a second sensor 28 facing into a medium conveying path are positioned slightly dislocated from each other in the direction for medium conveying. This dislocated amount is converted to the number of steps of a motor 33, and a value to which correction of a range allowing bias feeding is stored in a memory 34. The number of steps of the motor required for a medium to be conveyed between the first sensor 27 and the second sensor 28 is counted by a counting means 36. The number of steps by this counting means 36 is compared with the number of steps stored in the memory 34 by a comparison means 37, and bias feeding is determined based on its result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medium skew detecting method widely used in printers and original reading apparatuses and the like, and an apparatus therefor.

[0002]

2. Description of the Related Art In general, this type of medium skew detection method includes:
A pair of sensors facing the medium transport path are arranged in a direction orthogonal to the medium transport direction, and the pair of sensors detects both ends in the width direction of the medium. That is,
When the pair of sensors detects the front end of the medium inserted and conveyed in the medium insertion path at the same time, it is determined that the sheet is not skewed, and when these sensors are not simultaneously detected, it is determined that the sheet is skewed. Was.

[0003]

However, in the above-described conventional medium skew detection method, even when the medium is not skewed, if the pair of sensors is not arranged in a direction orthogonal to the medium conveyance direction, There is a risk that skew is erroneously determined. For this reason, it is necessary to arrange the sensors with high precision so that there is no manufacturing error or assembly error, so that not only the assembling work becomes complicated, but also the adjustment time becomes longer. In addition, there is also a problem that the usability of the user is poor because a slight deviation that allows skew is determined to be skew.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to prevent erroneous detection of skew due to manufacturing errors and assembly errors, and to facilitate medium skew. An object of the present invention is to provide a line detection method and a device thereof.

[0005]

In order to achieve this object, a medium skew detecting method according to the present invention comprises a first sensor for detecting one side in a width direction of a medium and a second side detecting a second side for a medium.
The second sensor is disposed downstream of the first sensor with respect to the medium, and the medium is transported between the time when the medium is detected by the first sensor and the time when the medium is detected by the second sensor. The skew of the medium is detected by comparing the number of steps of the transport motor required to perform the operation with a value obtained by converting the displacement of the pair of sensors into the number of steps of the motor. Therefore, as a result of the comparison, when a deviation equal to or more than the deviation between the first sensor and the second sensor is detected, it is determined that the skew is present.

[0006]

1 shows a skewed medium detecting device according to the present invention, wherein FIG.
(B) is a front view with a part cut away, (c) is a side view with a part cut off, FIG. 2 is a block diagram of a control unit for controlling the skew detector, and FIG. FIG. 4 is a detailed diagram illustrating a skew detection method, and FIG. 4 is a flowchart showing the same operation. In FIG. 1, a medium transporting device generally indicated by reference numeral 1 includes side plates 2a and 2b and an upper plate 2c that face each other.
Is provided with a frame 2 having a U-shaped cross section. Inside one side plate 2a of this frame 2,
A reference wall 3 having substantially the same overall length as the side plate 2a is fixed. On the inner side surface of the reference wall 3, the reference wall 3
A recess 3a extending in the longitudinal direction of the recess 3a is formed.
The inner side surface 3b of a forms a reference wall surface against which one side end of the medium conveyed in the medium conveyance path 6 described later is pressed.

A transport path lower surface plate 4 and a transport path upper surface plate 5, both formed of flat plates, are fixed to the reference wall 3 and the side plate 2b of the frame 2. These reference walls 3
b, transport path lower plate 4, transport path upper plate 5, and frame 2
And the side plate 2b, a medium transport path 6 is formed.
A front guide plate 7 is provided at the front end of the medium conveyance path 6 and extends in the width direction of the medium conveyance path 6 so as to be orthogonal to the medium conveyance path 6. A medium insertion port 8 is formed by the face plate 4, and the medium is manually inserted into the medium conveyance path 6 in the direction of arrow A from the medium insertion port 8.

Below the lower surface plate 4 of the conveyance path, two rotating shafts 9, 10 rotatably supported between both side plates 2a, 2b of the frame 2 are orthogonal to the reference wall surface 3b of the reference wall. The rotating shafts 9 and 10 are configured to rotate using a motor 33 that transports a medium as a drive source. Each of these rotating shafts 9 and 10 has
Drive rollers 11 and 12 facing the inside of the medium transport path 6 from a window formed in the transport path lower surface plate 4 are mounted on the shaft.

Above the rotating shaft 9, a rotating shaft 14 is rotatably supported between both side plates 2a and 2b of the frame 2. The rotating shaft 14 is driven by a solenoid (not shown) as shown in FIG. ), It is configured to be rotationally driven within a predetermined range in clockwise and counterclockwise directions, and to be held at respective rotational ends. A plurality of shutters 15 are screwed to the rotating shaft 14 so as to be arranged in the axial direction. The rear end of the shutter 15 is bent downward and formed on the transport path upper surface plate 5. It can move back and forth from the slit to the medium transport path 6.

A pair of brackets 16 and 17 having a substantially U-shaped cross section are rotatably supported on the rotating shaft 14. One of the side surfaces of the brackets 16 and 17 has a front end formed of a medium in a plan view. The arm 1 extends in the direction opposite to the insertion direction A
6a and 17a are formed. These arms 16a, 1
7a has a pair of skew correction rollers 19 and 20 respectively.
Are rotatably supported, and both rollers 19,
The rotation axis 20 is inclined so as to form an obtuse angle γ with the reference wall surface 3b in a plan view.

A torsion coil spring (not shown) is interposed between the brackets 16 and 17 so that the rollers 19 and 20 are urged away from the drive roller 11 from the window of the upper plate 5 of the transport path. Have been. When a plunger (not shown) is operated to rotate the rotating shaft 14, both rollers 19 and 20 rotate toward the drive roller 11 against the torsional force of the torsion coil spring. The skew correction rollers 19 and 20 are configured to be in contact with the drive roller 11 and to be pressed and conveyed between the two rollers 19 and 20 and the drive rollers 11 and 11.

The downstream side of the rotating shaft 14 in the medium transport direction (arrow A)
In the direction (direction), a shaft 22 is suspended between the side plates 2a and 2b of the frame 2, and a plurality of brackets 23 are rotatably supported on the shaft 22 on the base end side. A pinch roller 24 facing the drive roller 12 is rotatably supported on the free end side of the bracket 23 so that its axis is orthogonal to the reference wall surface 3b. The pinch roller 24 is rotationally urged by a spring (not shown) in a direction in which the pinch roller 24 is pressed against the drive roller 12.

Reference numeral 25 denotes a clamp sensor provided on the reference wall 3 side, which is positioned closer to the medium insertion port 8 than the rear end of the shutter 15. Reference numerals 27 and 28 denote a first sensor and a second sensor, which are a pair of skew detection sensors provided on the left and right of the rear end of the medium transport path 6. The pair of sensors 27 and 28 are provided at a distance L slightly smaller than the width of the minimum width medium in a direction orthogonal to the reference wall surface 3b. The first sensor 27 and the second sensor 28 are provided at positions slightly shifted with respect to the transport direction A of the medium. That is, as shown in FIG. 3, the second sensor 28 is provided on the downstream side in the paper transport direction A with a position shifted from the first sensor 27 by a length corresponding to δ steps of the motor 33 for transporting the medium. Have been.
Reference numeral 30 denotes a plurality of medium width detection sensors for detecting the width of the medium.

In FIG. 2, a reference numeral 34 denotes a rewritable storage in which α steps and β steps, which are allowable ranges of skew, are stored by the above-mentioned δ step and ± Q steps allowing a skew set in advance. Memory. That is, as in the case of the medium 31A, when the front left end X detected by the second sensor 28 is transported in advance in the direction of the arrow A, that is, in the case of so-called left skew, the first sensor 27 When the skew is not skewed more than Q steps from the reference line G, α = δ−Q as a lower limit value that is not regarded as skew.
Is set.

In the case where the front left end X is conveyed with a delay in the direction of arrow A as in the case of the medium 31B, that is, when the front left end X is skewed to the right, a step Q with respect to the reference line G of the first sensor 27 is performed. If there is no skewing, β = δ + Q is set as an upper limit value that is not regarded as skew. As described above, the deviation between the first sensor 27 and the second sensor 28 is stored in the memory 34 as a δ step, so that the deviation including the error generated at the time of manufacture or assembly is stored in the memory 34. So that both sensors 27, 28
It is not necessary to adjust an error in manufacturing or assembling the space between the gaps, so that assembling is facilitated and erroneous detection of skew can be prevented. In addition, since the skew is detected through the number of steps of the motor 33, a range ± Q steps in which the skew is allowed can be set, and the usability of the user is improved.

Reference numeral 35 denotes a control unit having a counting means 36 and a comparing means 37, which stores a program for controlling the entire skew detecting device 1, and includes a clamp sensor 25, a first sensor 27, and a second sensor. 28, a motor 33 and a memory 34 are connected. The counting means 36 starts counting when the medium is detected by the first sensor 27,
The number of steps of the motor 33 until the medium is detected by the second sensor 28 is counted. Comparison means 3
Numeral 7 is for comparing the number of steps counted by the counting means 36 with α and β stored in the memory.

Next, the skew detecting operation of the skew feeding device having such a configuration will be described. When the medium is not inserted into the medium transport path 6, the rear end of the shutter 15 has advanced into the card transport path 6.
20 is separated from the drive roller 11, and the motor 33 is not driven to rotate, so that the drive rollers 11, 12 are not rotating. In this state, when a medium (not shown) is inserted into the medium transport path 6 from the medium insertion port 8, in S1, the clamp sensor 25 detects the medium and turns ON.

When the clamp sensor 25 is turned on, a solenoid (not shown) is operated to rotate the shaft 14, so that the rear end of the shutter 15 retreats from the card transport path 6 and the skew roller 1
9 and 20 are in contact with the drive roller 11. At the same time, the motor 33 is driven, and the medium is nipped by the skew correction rollers 19 and 20 and the drive roller 11 and is conveyed in the medium insertion path 6 in the direction of arrow A. Since the rotation axes of the skew correction rollers 19 and 20 are inclined at an angle γ with respect to the reference wall 3b of the reference wall 3, the medium is conveyed in the direction of arrow A and skews toward the reference wall 3b at the same time. By pressing one side of the medium against the reference wall surface 3b, the medium is transported in the direction of arrow A while correcting the skew.

When the clamp sensor 25 is turned on,
In S2, the count value “n” of the counting means 36 of the control unit 35 is reset to “0”. In S3,
The motor 33 is driven by “1” step, and in S4,
If the first sensor 27 is not turned on, the motor 33 is driven by "1" step in S3. When the front end of the medium is detected by the first sensor 27 and the first sensor 27 is turned on, the motor 33 is driven by “1” step in S5, and the number of steps is “1” in S6.
The counting by the counting means 36 starts.

If the second sensor 28 is not turned on in S7, the motor 33 is driven by "1" step in S5. In S6, the counting means 36 counts n = n + 1 as the number of steps of the motor 33. You. In S7, when the front end of the medium is detected by the second sensor 28 and the second sensor 28 is turned on, in S8, the comparison unit 37 of the control unit 35 stores "n" counted by the counting unit 36 in the memory 34. Compare the stored α and β. As a result of the comparison, when “n” is not α ≦ n ≦ β, the controller 35 determines that the skew is present, the motor 33 is driven to rotate in reverse in S9, and the medium is discharged from the medium insertion port 8 in S10.

Since the medium determined to be skewed is ejected from the medium insertion port 8 in this way, erroneous printing is not performed on the skewed medium, and wasteful consumption of the medium is prevented. Can be prevented. In S8, “n” is α ≦
If n ≦ β, the control unit 35 determines that there is no skew, the motor 33 is driven, the medium is conveyed in the direction of arrow A, the medium width is detected by the medium width detection sensor 30, and the medium is conveyed. The paper is discharged from the rear of the path 6 and printed by a printing unit (not shown).

In this embodiment, ± Q steps are provided with respect to δ as an allowable range of skew. However, if it is not necessary to provide δ, it is of course possible to set Q = 0. is there. Although the rewritable memory 34 is provided, the memory 34 may be built in the control unit 35 if rewriting is unnecessary and used as fixed data.

[0023]

As described above, according to the present invention, assembling is facilitated and erroneous detection of skew can be prevented. Further, since the skew is detected based on the number of steps of the motor, a range in which the skew is allowed can be set, and the usability of the user is improved.

According to the second aspect of the present invention, it is possible to prevent erroneous printing on a skewed medium and prevent unnecessary consumption of the medium.

[Brief description of the drawings]

1A and 1B show a skew detection device according to the present invention, wherein FIG. 1A is a partially cutaway plan view, FIG. 1B is a partially cutaway front view, and FIG. It is a side view shown broken.

FIG. 2 is a block diagram of a skew detection device according to the present invention.

FIG. 3 is a detailed diagram illustrating a skew detection method in the skew detection device according to the present invention.

FIG. 4 is a flowchart illustrating an operation of the skew detection device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Skew detecting device, 6 ... Medium conveyance path, 11, 12 ... Drive roller, 19,20 ... Skew correction roller, 25 ... Clamp sensor, 27 ... First sensor, 28 ... Second sensor, 3
3 ... motor, 34 ... memory, 35 ... control unit, 36 ... counting means, 37 ... comparing means.

Continued on the front page (72) Inventor Kazuo Ito 2-3-2 Shimomeguro, Meguro-ku, Tokyo Inside Tamura Electric Works, Ltd. (72) Mikio Nagai 5-7-1 Shiba 5-chome, Minato-ku, Tokyo NEC Corporation (72) Inventor Naoya Takayama 3-49-1, Kamiishihara, Chofu-shi, Tokyo Japan Electric Data Equipment Co., Ltd.

Claims (3)

[Claims] A first sensor for detecting one side in the width direction of the medium, a second side for detecting the other side of the medium, a second sensor disposed downstream of the first sensor with respect to the medium, After the medium is detected by the first sensor, the second
Comparing the number of steps of the transport motor required to transport the medium until it is detected by the sensor with a value obtained by converting the displacement of the pair of sensors into the number of steps of the motor, and calculating the skew of the medium. A medium skew detection method characterized by detecting. 2. The medium skew detection method according to claim 1, wherein when the skew of the medium is detected, the transport motor is reversed to discharge the medium from the medium insertion port. 3. A pair of sensors provided side by side in a direction orthogonal to the medium transport direction and positioned at a slight distance from each other in the medium transport direction. Is converted as the number of steps of the motor that conveys, and a memory that stores the converted number of steps, and the medium is detected by the sensor on the upstream side in the medium conveying direction of the pair of sensors and then by the sensor on the downstream side. Counting means for counting the number of steps of the motor until detection, and comparing means for comparing the number of steps counted by the counting means with the number of steps stored in the memory; A skewed medium detection device.