JPH11268844A - Method and device for conveying sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To convey a sheet at high accuracy by easily and accurately correct unevenness of the speed of a rotational driving source when nip rollers are advanced or retreated in relation to a driving roller. SOLUTION: A sheet conveying device is provided with first and second roller pairs 50, 52, switch means 68a, 68b for advancing or retreating nip rollers 58a, 58b, DC motors 70a, 70b for driving the switch means 68a, 69b, detecting means 72a, 72b for detecting the rotational speed of the DC motors 70a, 70b, and a controller 14 for feedback-controlling the DC motors 70a, 70b on the basis of the rotational speed obtained by the detecting means 72a, 72b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for conveying a sheet by nipping and conveying a sheet by a driving roller which is driven to rotate and a nip roller which can move forward and backward with the driving roller.

[0002]

2. Description of the Related Art For example, stimulable phosphors (stimulable phosphors)
There is known a system that once records radiation image information of a subject such as a human body, reproduces the radiation image information on a photographic photosensitive material such as a photographic film, or outputs a visible image on a CRT or the like. I have.

The stimulable phosphor is composed of radiation (X-ray, α-ray, γ
(Rays, electron beams, ultraviolet rays, etc.), a part of this radiation energy is accumulated, and after irradiation with excitation light such as visible light, a phosphor that emits stimulated emission according to the accumulated energy is referred to. This stimulable phosphor is usually formed into a sheet and used as a stimulable phosphor sheet.

In the above system, for example, a reading section for reading image information recorded on the stimulable phosphor sheet and an erasing section for erasing image information remaining on the stimulable phosphor sheet after reading are provided. An image information reading device is employed. In this image information reading apparatus, a cassette accommodating a stimulable phosphor sheet on which radiation image information of a subject is recorded by an external photographing device is inserted into a loading section. Next, in a state where the cassette is opened, the stimulable phosphor sheet is taken out from the cassette under the operation of the sheet body sheet feeding mechanism, and the stimulable phosphor sheet is transported to the reading unit via the sheet body transport mechanism. Is done. The stimulable phosphor sheet on which the reading process has been performed by the laser beam irradiation in the reading unit is erased in the erasing unit, and then stored in a cassette arranged in the loading unit.

On the other hand, in the above system, an image information reproducing apparatus for reproducing radiation image information on a photographic photosensitive material such as a photographic film is used. In this image information reproducing apparatus, the photographic light-sensitive materials are taken out one by one from a magazine containing a plurality of photographic light-sensitive materials and transferred to a recording unit. In the recording unit, radiation image information obtained from the stimulable phosphor sheet is exposed and recorded on a photographic photosensitive material by irradiation with laser light or the like.

In the reading section and the recording section, when the main scanning is performed by irradiating a light beam such as a laser beam to a sheet body such as a stimulable phosphor sheet or a photographic photosensitive material, the sheet body is moved in the scanning direction. A sub-scanning conveyance mechanism that conveys in a substantially orthogonal sub-scanning direction is used. In this sub-scanning conveyance mechanism, in order to convey the sheet body in the sub-scanning direction with high precision and smoothness, two pairs of rollers are disposed at intervals shorter than the length of the sheet body in the conveyance direction. A configuration in which the roller pair is rotated synchronously is employed.

In this case, when the sheet body enters between the roller pairs or attempts to separate from the roller pair,
A considerable impact is likely to be generated on the sheet member, and there is a possibility that the reading process and the exposure recording process of the sheet member may not be performed accurately.

Accordingly, for example, Japanese Patent Application Laid-Open No. 63-47241 discloses
As disclosed in Japanese Patent Application Laid-Open Publication No. H10-209, by controlling a motor and a solenoid, one roller (hereinafter, referred to as a nip roller) constituting each roller pair is changed to another roller (hereinafter, referred to as a drive roller) that is rotationally driven. There is known a method in which the object is moved toward and away from the object.

[0009]

In the above prior art,
Control of a motor and a solenoid for moving the nip roller forward and backward is performed by a closed loop control system. However, the speed of a motor or a solenoid varies due to a difference in the product itself, a change in temperature, a change with time, or the like. For this reason, uneven conveyance is likely to occur during the sub-scanning conveyance of the sheet body. For example, the irradiation position of the laser beam on the stimulable phosphor sheet is shifted, and the image information obtained from the stimulable phosphor sheet is inaccurate. Has been pointed out.

SUMMARY OF THE INVENTION The present invention is to solve this kind of problem, and it is possible to constantly and easily control the advance / retreat speed of a nip roller for nipping and transporting a sheet to a desired speed with high accuracy. It is intended to provide a method and apparatus.

[0011]

In the method and apparatus for conveying a sheet member according to the present invention, when a sheet member is held between a driving roller and a nip roller which are driven to rotate, or when the driving roller and the nip roller are interposed between the driving roller and the nip roller. When the sheet body separates from between, the nip roller advances and retreats with respect to the drive roller under the action of a rotary drive source.

Here, when the rotation drive source is driven, the rotation speed of the rotation drive source is detected, and the rotation drive source is feedback-controlled based on the detected rotation speed. For this reason, it is possible to reliably correct unevenness in rotation caused by, for example, a difference between a motor and a solenoid, a change in temperature or a change with time, which is used as a rotation drive source. Thus, the nip roller can always be moved forward and backward with respect to the drive roller at a stable speed, and it is possible to effectively avoid an impact when the sheet body is pinched or when the sheet body comes off.

The opening / closing means for moving the nip roller forward and backward includes a cam member connected to a rotary drive source and rotating, and a swing cam engaged with the cam member to move the nip roller forward and backward with respect to the driving roller. ing. Therefore, it is possible to impart a desired operation to the nip roller only by controlling the rotation of the rotary driving source at a constant speed, and the feedback control of the rotary driving source is simplified at a stroke.

The detecting means includes an arcuate dog member which rotates integrally with the cam member, and a sensor which is turned on / off by passing the dog member. In this detection means, when a rotary drive source, for example, a DC motor or a rotary solenoid is driven at a predetermined voltage,
When the cam member rotates and the dog member that rotates integrally with the cam member blocks the sensor, the sensor is turned off. Next, a time is measured until the dog member is separated from the sensor and the sensor is turned on again, and the rotation speed of the rotary drive source is detected based on the measured time. Therefore, by correcting the voltage of the rotary drive source based on the rotational speed of the rotary drive source, the advance / retreat speed of the nip roller can be accurately corrected to a desired speed.

[0015]

FIG. 1 is a schematic structural explanatory view of an image information reading apparatus 12 incorporating a sub-scanning conveying mechanism 10 which is a sheet conveying apparatus according to an embodiment of the present invention.

A touch panel 14 having the functions of an operation unit and a monitor is provided on the upper front surface of the image information reading device 12, and a cassette loading unit 18 to which a cassette 16 can be attached and detached is provided below the touch panel 14. The cassette 16 has a housing 22 for accommodating a stimulable phosphor sheet (sheet body) 20 and a lid 26 capable of opening and closing an opening 24 of the housing 22. Opening / closing means (not shown) for opening and closing the lid 26 is provided.

The stimulable phosphor sheet 20 accommodated in the cassette 16 is taken out of the cassette loading section 18 and the stimulable phosphor sheet 20 after reading and erasing described later is returned to the cassette 16. A sheet unit 28 is provided. The sheet unit 28 includes a plurality of suction plates 30 communicating with a negative pressure source.

An erasing unit 34 and a reading unit 36 are disposed below the sheet unit 28 via a transport system 32. The transport system 32 includes a plurality of pairs of rollers 38, and a plurality of erasing light sources 40 constituting the erasing unit 34 are arranged on a vertical transport path formed by the pair of rollers 38.

The reading unit 36 transports the stimulable phosphor sheet 20 taken out of the cassette 16 in the sub-scanning direction (the direction of arrow A) according to the present embodiment.
And the stimulable phosphor sheet 2 conveyed in the sub-scanning direction
The optical system 42 irradiates the laser light L in the main scanning direction (a direction substantially orthogonal to the sub-scanning direction) at 0, and stimulates the photostimulated emission light generated from the stimulable phosphor sheet 20 by the irradiation of the laser light L. And a light-collecting system 44 for reading. The light condensing system 44 includes a light guide 46 arranged along a main scanning line at a scanning position of the laser beam L on the stimulable phosphor sheet 20, and a photomultiplier 48 mounted on the light guide 46. Is provided.

As shown in FIGS. 2 and 3, the sub-scanning transport mechanism 10 includes first and second roller pairs 50 and 52 which are driven to rotate in synchronization with each other. The first and second roller pairs 50 and 52 are driven integrally with a driving roller 56a, 56b via a motor 54, and are disposed on the driving rollers 56a, 56b so as to be able to advance and retreat. And nip rollers 58a and 58b capable of holding the nip rollers. An endless belt 60, which is engaged with the motor 54 and runs around, is stretched over the ends of the drive rollers 56a and 56b.

Both ends of the nip rollers 58a, 58b are rotatably supported on one end of a pair of support plates 62a, 62b, respectively, and one end of a tension spring 66a, 66b is mounted on the other end of each of the support plates 62a, 62b. Fixed. The nip rollers 58a, 58b are pressed and supported by the peripheral surfaces of the drive rollers 56a, 56b under the action of the tension springs 66a, 66b. Each of the drive rollers 56a and 56b and the nip rollers 58a and 58b is composed of a plurality of rubber rollers each having a predetermined width in the axial direction.

The sub-scanning transport mechanism 10 includes a nip roller 58
opening / closing means 68a, 68b for advancing / retreating the driving rollers 56a, 56b with respect to the driving rollers 56a, 56b;
68b, for example, a DC motor 70
a, 70b, detecting means 72a, 72b for detecting the rotational speed of the DC motors 70a, 70b, and the DC based on the rotational speed obtained by the detecting means 72a, 72b.
A controller (control means) 74 for performing feedback control of the motors 70a and 70b.

The opening / closing means 68a includes a cam member 78 which is connected to a drive shaft 76 of the DC motor 70a and rotates, and a swing cam 80 which engages with the cam member 78 and swings. As described later, the cam member 78 has a cam surface shape such that the nip roller 58a advances and retreats at a desired speed pattern with respect to the drive roller 56a via the swing cam 80. The swing cam 80 is swingable about a support shaft 82, and the swing cam 80 is fixed to both ends of the support shaft 82, respectively.

The cam member 7 is attached to the long plate 84 of the swing cam 80.
8 is in contact with the long plate portion 84 and the support shaft 82
A claw portion 86 is formed on a short portion protruding outward from the side. The claw portion 86 extends toward the support plate 62a, and can freely contact the shaft portion of the nip roller 58a.

The detecting means 72a is provided integrally with the cam member 78, and is provided with an arcuate dog member 88 set over a predetermined angle range with respect to the axis of rotation, and is turned on by the passage of the dog member 88. / Off sensor 90. The sensor 90 is, for example, a photosensor integrally provided with a light emitter and a light receiver, and outputs an off signal when the dog member 88 blocks the sensor 90, while the dog member 88 is separated from the sensor 90. In this case, an ON signal is output, and these signals are sent to the controller 74. The controller 74 is connected with a timer 92 for measuring time and a drive circuit 94 for driving the DC motors 70a and 70b.

The opening / closing means 68b and the detecting means 72
b has the same configuration as that of the opening / closing means 68a and the detection means 72a, and the same components are denoted by the same reference characters and will not be described in detail.

The sub-scanning transport mechanism 10 thus configured
Is described below in relation to the sheet conveying method according to the present embodiment.

First, the stimulable phosphor sheet 20 on which radiation image information of a subject such as a human body is recorded by a photographing device (not shown) is housed in the cassette 16 in a light-shielded state to constitute the image information reading device 12. Cassette loading section 1
Set to 8. When the cassette 16 is loaded, the lid 26 of the cassette 16 is swung to a predetermined angular position by an unlocking means (not shown) provided in the cassette loading section 18, and the opening 24 is opened.

Next, the suction disk 30 is moved into the cassette 16 under the driving action of the sheet unit 28, and the stimulable phosphor sheet 20 in the cassette 16 is suctioned by the suction disk 30. Further, the suction disk 30 is provided with the stimulable phosphor sheet 2.
0, the cassette 16 and the transport system 32
Side, the stimulable phosphor sheet 20
Is pinched by a pair of rollers 38 constituting the transport system 32.

At this time, the suction holding of the stimulable phosphor sheet 20 by the suction disk 30 is released. As a result, the stimulable phosphor sheet 20 is transferred to the transport system 32, and under the action of the transport system 32, the stimulable phosphor sheet 20 is once transported to the reading unit 36 through the erasing unit 34. Is done.

In the reading section 36, the stimulable phosphor sheet 20
Is detected by a sensor (not shown), the motor 54 is driven to drive the driving rollers 56a and 56b forming the first and second roller pairs 50 and 52, as shown in FIG.
Are synchronously driven to rotate under the action of the belt 60.

As shown in FIG. 4, the stimulable phosphor sheet 20 is inserted between the first roller pair 50, and is driven by the driving roller 56a and the nip roller 58a constituting the first roller pair 50 so as to be in the auxiliary state. While being conveyed in the scanning direction (the direction of arrow A), the optical system 42 is driven to irradiate the stimulable phosphor sheet 20 with the laser light L in the main scanning direction (see FIG. 1). Therefore, the stimulable light is emitted from the stimulable phosphor sheet 20, and the stimulable light is emitted from the light guide 46.
The radiation image information is stored in the stimulable phosphor sheet 20 and is read photoelectrically.

When the leading end side of the stimulable phosphor sheet 20 approaches the second roller pair 52, a drive signal of the DC motor 70 b is input from the controller 74 to the motor drive circuit 94. Thereby, the DC motor 70b is driven, and the cam member 78 constituting the opening / closing means 68b is rotated in the direction of arrow B in FIG. Swings in the direction of arrow C with the support shaft 82 as a fulcrum.

When the swing cam 80 swings in the direction of arrow C,
The claw portion 86 comes into contact with the shaft portion of the nip roller 58b, and this nip roller 58b is integrated with the supporting plate 62b by the tension spring 6
6b. Therefore, the nip roller 5
8b moves upward, and a predetermined gap is formed between the nip roller 58b and the driving roller 56b (see FIG. 5).

While the leading end of the stimulable phosphor sheet 20 enters between the driving roller 56b and the nip roller 58b, the cam-shaped surface of the cam member 78 presses the swing cam 80 to maintain the nip roller 58b upward. ing. And
When the cam-shaped surface of the cam member 78 shifts to the small-diameter portion, the swing cam 80 returns the long plate portion 84 in the vertical direction. For this reason, as shown in FIG. 6, the driving roller 56b and the nip roller 58b sandwich the leading end side of the stimulable phosphor sheet 20, and the stimulable phosphor sheet 20
Is transported at a constant speed in the sub-scanning direction via the first and second roller pairs 50 and 52.

Further, as shown in FIG. 7, when the rear end side of the stimulable phosphor sheet 20 is transferred to the vicinity of the first roller pair 50, the DC motor 70a is driven via the controller 74. As a result, the nip roller 58a is separated from the drive roller 56a under the driving action of the opening / closing means 68a, and the rear end of the stimulable phosphor sheet 20 passes through the first roller pair 50.
It moves to 6a side and abuts each other.

The stimulable phosphor sheet 20 that has been subjected to the reading processing of the radiation image information by the reading section 36 is transferred to the transport system 3.
2, the remaining radiation image information is erased via a plurality of erasing light sources 40 provided in the erasing unit 34 when the image is moved vertically upward. And
After the stimulable phosphor sheet 20 is fed into the cassette 16 via the sheet portion 28, the cassette 16 is pulled out from the cassette loading section 18. At this time, since the lid 26 closes toward the housing 22 via a lid (not shown), the cassette 16 is taken out of the image information reading device 12 with the opening 24 being shielded from light.

In the sub-scanning transport mechanism 10, the first
And D to open and close the second roller pair 50, 52.
C motors 70a and 70b are used,
The rotation speeds of the motors 70a and 70b are likely to vary due to differences (instrument differences) of the products themselves, temperature changes or changes over time due to use, and the like.

Therefore, in this embodiment, the DC motor 70
By performing the feedback control on the DC motors a and 70b, the variation in the speed of the DC motors 70a and 70b can be effectively corrected. That is, the DC motor 70a will be described. When the DC motor 70a is driven at a predetermined voltage V0, the cam member 78 makes one revolution to move the nip roller 58a forward and backward with respect to the drive roller 56a, A dog member 88 provided on the member 78 passes through a sensor 90 constituting the detecting means 72a.

The sensor 90 outputs an off signal to the controller 74 when the optical path is interrupted by the dog member 88,
When the dog member 88 moves into and out of the optical path of the sensor 90, an ON signal is output to the controller 74. The controller 74 measures the time by the timer 92, and measures a time t1 from when the off signal is input from the sensor 90 to when the on signal is input.

Here, in the DC motor 70a, the voltage and the number of rotations have a proportional relationship, and by design, the time from when the sensor 90 obtains an off signal to an on signal when the voltage is V0 is time t0. If so, the DC motor 70a
Drive control is performed at a voltage V obtained from t1 / t0 × V0 = V. Thus, the advance / retreat speed of the nip roller 58a is corrected to a desired speed.

As described above, in the present embodiment, the rotation speed of the DC motor 70a is detected as the time measured from the OFF signal to the ON signal obtained from the detection means 72, and the voltage (V) corrected based on the detection result. ), The DC motor 70a is feedback controlled. Therefore, even if the speed of the DC motor 70a varies due to an instrumental difference, a temperature change, a change over time, or the like, the DC motor 70a can be controlled to a desired rotational speed, and the sub-scanning transport mechanism 1 can be controlled.
0 has the effect that the sub-scanning conveyance of the stimulable phosphor sheet 20 is performed smoothly and with high precision.

In addition, since the reciprocating operation of the nip roller 58a is performed by the cam member 78 and the swing cam 80 constituting the opening / closing means 68a, the rotational speed of the DC motor 70a can be set to a constant speed. This allows DC
There is an advantage that control of the motor 70a is simplified at a stroke. Further, by using the DC motor 70a as the rotation drive source, it is possible to use the proportional relationship between the voltage and the number of rotations, and the correction processing of the DC motor 70a is performed simply and quickly.

Further, a cam member 78 and a swing cam 80 are provided as the opening / closing means 68a, and a DC motor 70a is used as a rotation drive source. Therefore, the configuration of the entire apparatus is simplified, and the equipment cost does not rise. Further, the controller 74 operates as a timer 92.
Accordingly, the DC motor 70a is constantly managed, and when the rotation speed detected based on the on / off signal obtained from the detection unit 72a exceeds the set speed, it is possible to output a warning signal as an abnormality. .

In this embodiment, the time from when the OFF signal is input to the controller 74 from the sensor 90 constituting the detecting means 72a to when the ON signal is input is measured. The time from the input to the input of the off signal may be measured. Further, a contact type, for example, a limit switch may be used as the sensor 90 instead of the photo sensor. Further, a rotary solenoid or the like may be used instead of the DC motor 70a as a rotary drive source.

In the above description, only the DC motor 70a side has been described, but the same effect can be obtained on the DC motor 70b side. The DC motors 70a, 7
The speed correction of 0b does not need to be performed every time the stimulable phosphor sheet 20 is read, and may be arbitrarily performed every predetermined time or every day.

Further, in the present embodiment, the sub-scanning transport mechanism 10 is incorporated in the image information reading device 12, but this sub-scanning transport mechanism 10 may be incorporated in the image information reproducing device.

[0048]

In the sheet conveying method and apparatus according to the present invention, when the nip roller advances and retreats with respect to the drive roller under the action of the rotary drive source, the rotational speed of the rotary drive source is detected to detect the rotational drive source. The above-described feedback control makes it possible to easily and reliably correct the speed unevenness of the rotary drive source. This makes it possible to convey the sheet body smoothly and with high precision via the nip roller and the driving roller with a simple control.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image information reading apparatus incorporating a sheet conveying apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective explanatory view illustrating a schematic configuration of the sheet conveying apparatus.

FIG. 3 is an explanatory front view partially in section of the sheet conveying apparatus.

FIG. 4 is an explanatory diagram of an operation when a stimulable phosphor sheet is carried into the sheet conveying apparatus.

FIG. 5 is an explanatory diagram of an operation when the stimulable phosphor sheet is conveyed between a first and a second roller pair constituting the sheet conveying apparatus.

FIG. 6 is an operation explanatory diagram when the stimulable phosphor sheet is nipped and conveyed by the first and second roller pairs.

FIG. 7 is an operation explanatory diagram when a rear end of the stimulable phosphor sheet is separated from the first roller pair.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Sub-scanning conveyance mechanism 12 ... Image information reading device 16 ... Cassette 18 ... Cassette loading part 20 ... Storable phosphor sheet 28 ... Sheet-sheet part 32 ... Transport system 34 ... Erasing part 36 ... Reading part 42 ... Optical system 44 ... Condensing system 50, 52 Roller pair 54 Motor 56a, 56b Driving roller 58a, 58b Nip roller 60 Belt 62a, 62b Support plate 68a, 68b Opening / closing means 70a, 70b DC motor 72a, 72b Detection means 74: controller 78: cam member 80: swing cam 88: dog member 90: sensor 92: timer 94: drive circuit

Claims (4)

[Claims] 1. A driving roller which is driven to rotate, and a nip roller which can move forward and backward with respect to the driving roller via opening / closing means,
A sheet conveying method for nipping and conveying a sheet, comprising: a step of driving the opening / closing means to move the nip roller with respect to the driving roller under the action of a rotation driving source; A sheet conveying method, comprising: detecting a rotation speed; and performing feedback control of the rotation drive source based on the detected rotation speed. 2. A sheet conveying device for nipping and conveying a sheet by a driving roller that is driven to rotate and a nip roller that can move back and forth to the driving roller, wherein the nip roller is moved forward and backward with respect to the driving roller. Means, a rotation drive source for driving the opening / closing means, detection means for detecting a rotation speed of the rotation drive source, and control for feedback-controlling the rotation drive source based on the rotation speed obtained by the detection means. Means for conveying a sheet body. 3. The sheet conveying apparatus according to claim 2, wherein the opening / closing means includes a cam member connected to the rotation drive source and rotating, a nip roller engaged at one end, and the cam at the other end. A swinging cam that engages a member and swings under the rotation of the cam member to move the nip roller forward and backward with respect to the driving roller. 4. The sheet conveying apparatus according to claim 2, wherein said detecting means rotates integrally with said cam member, and has an arcuate dog member provided over a predetermined angular range; And a sensor that performs an on / off operation.