JPH0759028B2 - Control method for sheet conveying system - Google Patents

Description

The present invention relates to a control method of a sheet conveying system in a light beam scanning device, and more specifically, to a storage phosphor sheet or an image carrying radiation image information. When reading or writing image information while nipping and conveying a sheet body such as a film to be recorded, each roller forming the nip roller moves in a direction in which they approach each other for nipping the sheet body. Speed of nipping the sheet body (hereinafter referred to as nipping speed), speed of moving in a direction in which they are separated from each other in order to release the nipping of the sheet body (hereinafter, referred to as separation elementality), and rotation speed of the nip roller By setting the conveying speed of the sheet body according to the above-mentioned condition to a predetermined speed in advance based on the image reading condition or the writing condition, On the possibility and the control method of the sheet member transport system to improve the throughput of over beam scanning apparatus as much as possible.

BACKGROUND OF THE INVENTION Recently, a radiation image recording / reproducing system that obtains a radiation image of a subject using a stimulable phosphor (stimulable phosphor) has been attracting attention. Here, the stimulable phosphor means radiation (X-ray, α
Radiation, β rays, γ rays, electron rays, ultraviolet rays, etc.) accumulates a part of this radiation energy, and by irradiating excitation light such as visible light later, stimulated emission depending on the accumulated energy. A phosphor that emits light.

The above-mentioned radiation image recording / reproducing system uses this stimulable phosphor, and the radiation image information of a subject such as a human body is once provided with a sheet having a layer made of a stimulable phosphor (hereinafter referred to as “accumulative phosphor sheet” or simply (Hereinafter referred to as "sheet"), the stimulable phosphor sheet is scanned with excitation light such as laser light to generate stimulated emission light, and the stimulated emission light is photoelectrically read to obtain an electric signal. Based on this electric signal, the radiation image of the subject is output as a visible image on a recording material such as a photographic photosensitive material or a display device such as a CRT.

Therefore, in such a radiation image recording / reproducing system, an image reading device for reading the radiation image from the stimulable phosphor sheet on which the radiation image is accumulated and recorded is specifically configured as follows.

That is, a stimulable phosphor sheet on which a radiation image is stored and recorded is loaded into the image reading device in a state of being stored in a cassette, a supply magazine, or the like, and the stimulable phosphor sheet is loaded through a sheet-fed mechanism including an adsorption plate or the like. The body sheets are taken out one by one from the cassette or the supply magazine.
Next, the separated stimulable phosphor sheet is conveyed to the reading unit via a conveying mechanism such as a belt. The reading unit performs sub-scanning by mechanically transporting the stimulable phosphor sheet in one direction, and a light beam such as a laser beam deflected in a direction substantially orthogonal to the transport direction of the stimulable phosphor sheet. Is irradiated to perform main scanning, and the photostimulated luminescent light thus obtained is detected in time series by a photodetector such as a photomultiplier to obtain image information. The stimulable phosphor sheet after image reading is conveyed to the erasing section,
The radiation image remaining on the stimulable phosphor sheet is erased by irradiating the erasing light from a sodium lamp or the like, and thereafter, the radiation image is accumulated in a receive magazine or the like.

Next, the image information obtained as described above is sent to the image recording device. The image recording device irradiates a photographic light-sensitive material, which is a recording material, with laser light modulated based on the image information obtained from a stimulable phosphor sheet, and exposes and records a predetermined image on the photographic light-sensitive material. Is configured. This photographic light-sensitive material on which an image has been newly recorded is subjected to development processing, then stored in a predetermined place, and used for medical diagnosis or the like as necessary.

Therefore, in the image reading apparatus or the image recording apparatus as described above, when reading or recording the image information, for example, the sheet is formed by a pair of rollers arranged at an interval shorter than the length of the sheet in the sub-scanning direction. The applicant of the present invention has already proposed a system in which a pair of rollers are sandwiched and one of the roller pairs is driven to convey the light beam in the main scanning direction while carrying the sub scanning at a predetermined speed (Japanese Patent Application No. 60- No. 232479).

By the way, the applicant of the present application, when the sheet is sub-scanned and conveyed by the above-described set of roller pairs, the roller pair is configured so that reading or recording can be performed from the front end of the sheet and reading or recording can be performed to the rear end of the sheet. One roller can be moved close to or away from the other roller,
It has been proposed to control the sandwiching of the seat (Japanese Patent Application No. 61-193533, etc.).

However, in such a sub-scanning conveyance mechanism, the speed of nipping the sheet body by the nip roller and the speed at which the nip roller separates from the sheet body are, for example, when the sub-scanning conveyance is performed at a relatively low speed during actual reading for image reproduction. It is set to the standard (This is because if the sheet body is pinched at high speed during reading or writing, or if the sheet body is released at high speed due to the separation of the rollers, the load fluctuation in the sheet conveying system will occur. (This is because it avoids the possibility that speed fluctuations will occur in the sub-scan transport direction of the sheet body as a result, and it will not be possible to reproduce a delicate image.)
Therefore, when the sub-scan conveyance may be performed at a high speed such as pre-read for grasping the outline of the recorded image prior to the main reading, the sub-scan conveyance may be appropriately performed because the sheet nipping or separating timing by the nip roller does not match. I can't. Therefore, it may be considered that the sub-scanning conveyance speed at the time of pre-reading is also set to be relatively low, but this has a disadvantage that the throughput of the image reading apparatus cannot be improved. The details of the pre-reading and the main reading have already been disclosed in JP-A-56-165111.

[Object of the Invention] The present invention has been made in order to overcome the above-mentioned inconvenience, and sandwiches a stimulable phosphor sheet carrying radiation image information or a sheet member such as a film for recording an image by using a nip roller. While carrying and reading or writing an image, the nip rollers nipping speed for nipping the sheet body, the separating speed for separating the sheet body, and the carrying speed for conveying the sheet body are predetermined nipping speeds by predetermined steps, By automatically setting a predetermined separation speed and a predetermined conveyance speed, it is possible to accurately read or write an image in the shortest possible time, and as a result, the overall throughput of the image reading apparatus is significantly improved. It is an object of the present invention to provide a control method for a sheet conveying system that enables the above.

[Means for Achieving the Object] In order to achieve the above object, the present invention performs main scanning with a light beam deflected in a one-dimensional direction with respect to a sheet body, and moves the sheet body in the conveying direction. A sheet body is sandwiched by a pair of first and second rollers arranged with a main scanning position by a light beam sandwiched at an interval shorter than the length, and the sheet is sub-scanned and conveyed.
In the method of two-dimensionally scanning the sheet body, it is detected that the leading end of the sheet body nipped and conveyed by the first roller pair approaches the second roller pair, and the first speed is detected in accordance with the conveyance speed of the sheet body. Control of the approaching speed at which the rollers forming the two roller pairs reach the sandwiching position of the sheet body, and / or by detecting that the rear end of the sheet body approaches the first roller pair, the sheet body is detected. It is characterized in that the speed at which the rollers forming the first roller pair are separated from the nipping position of the sheet body is controlled according to the conveying speed.

[Embodiment] Next, a method for controlling a sheet conveying system according to the present invention will be described in detail below with reference to preferred embodiments in relation to an apparatus for carrying out the method, with reference to the accompanying drawings.

In FIG. 1, reference numeral 10 indicates an image reading apparatus incorporating an apparatus for carrying out the control method of the transport system according to the present embodiment. A supply magazine 14 is removably attached to the chamber 12 in the image reading apparatus 10, and a storage phosphor sheet S on which a radiation image has been stored and recorded is stacked and stored in the supply magazine 14. There is. A single-wafer mechanism including a suction plate 16 is provided in the chamber 12 in the vicinity of the supply magazine 14, and an endless transport belt 18 for transporting the stimulable phosphor sheet S is provided below the suction disc 16. .

The conveyor belt 18 extends downward in the vertical direction and is bent so as to be oriented in the horizontal direction at the inner corner of the image reading device 10,
A plurality of rollers 20a to 20d arranged in the vertical direction are provided on one surface of the conveyor belt 18 so as to be in sliding contact therewith. Further, a large-diameter roller 22 is arranged on the lower bent portion of the conveyor belt 18.

Therefore, the scanning mechanism 24 is provided at the center of the lower side of the image reading device 10. In this case, the scanning mechanism 24 basically comprises an image reading unit 26 and a conveying unit 28 located below the reading unit 26 and slightly separated from the end of the conveying belt 18.

The reading unit 26 includes a laser light source 30, and the laser light source 30
A mirror 34 for scanning the laser light 32 on the sheet S, a galvanometer mirror 36, and a converging reflection mirror 38 are provided on the laser light deriving side. Further, a light guide 40 is arranged at the scanning position of the laser light 32 on the sheet S along the main scanning line, and a photomultiplier 42 is mounted on the light guide 40.

On the other hand, the transport unit 28 includes a first nip roller pair 44a, 44b and a second nip roller pair 46a, 46b, and a stimulable phosphor sheet transported between the nip roller pair 44a, 44b and 46a, 46b. Guide members 48a, 48b for holding S
Is provided. Also, nip roller pairs 44a, 44b and 46
Of the nip rollers that make up a and 46b, rollers 44a and 4
An endless conveyor belt 47 for placing and conveying the stimulable phosphor sheet S is arranged between the 6a. Further, optical sensors 41 and 43 for determining the presence or absence of the stimulable phosphor sheet S are arranged in close proximity to each other at both ends of the transport unit 28, and the sensors 41 and 43 are light sources 41a and 43a and a light receiving element, respectively. It consists of 41b and 43b.

A relatively large-diameter roller 52 and an endless conveyor belt 54 are disposed in the vicinity of the second nip roller pair 46a, 46b of the scanning mechanism 24 configured as described above. A second support roller 56b, which is provided above the support roller 56a and the roller 52 and is in sliding contact with the roller 57, and is installed on the second support roller 56b. Further, a tension roller 58 is in sliding contact with the inner peripheral surface of the conveyor belt 54, and one end of the tension roller 58 is pulled vertically downward by a coil spring 68 engaging with a side plate 60. Therefore, the tension roller 58 is constantly pulled vertically downward by the pulling force of the coil spring 68 to maintain the conveyor belt 54 in a predetermined tension state.

An endless conveyor belt 72 is provided above the second support roller 56b. The conveyor belt 72 extends vertically upward, is bent in the horizontal direction at its terminal end, and is further oriented with its tip end slightly downward. The conveyor belt
The portion of 72 that extends in the vertical direction is composed of a plurality of rollers 74a to 7a.
4e is slidably arranged, and a large-diameter roller 76 and rollers 78a and 78b are provided at the upper bent portion of the conveyor belt 72 so that the stimulable phosphor sheet S is conveyed vertically downward. Then, the stimulable phosphor sheet S is brought close to the roller 78b.
There is a receive magazine 80 for storing.

Furthermore, in the chamber 12, for example, an erasing section 82 is arranged between rollers 74b and 74c provided on the conveyor belt 72. A plurality of erasing light sources (not shown) are arranged inside the erasing section 82.

The present apparatus is further connected to a main body control unit 84 and a main body control unit 84 for integrally controlling the conveyance, reading, phenomenon, etc. of the stimulable phosphor sheet S, and the first nip roller pair 44a, 44b.
Further, a nip roller control unit 86 for controlling the nipping speed, the separating speed and the conveying speed of the second nip roller pair 46a, 46b is provided. As shown in FIG. 2, the nip roller control section 86 receives the stimulable phosphor sheet S from the main body control section 84.
The driving start signal for the information above the dimensions, the main reading process or the pre-entry process, and the nipping speed of the nip roller, the separating speed, and the conveying speed is introduced. The input information and the drive start signal are the interface section in the nip roller control section 86.
It is introduced into 88, and the input information is introduced into the speed switching unit 92 via the decoder unit 90. Further, the speed switching signal from the speed switching unit 92 is introduced into the first input terminal of the drive signal generating unit 94. On the other hand, the drive start signal is introduced to the second input terminal of the drive signal generating section 94 via the interface section 88. The output signal of the drive signal generation unit 94 is connected to the solenoid 98 that controls the nip speed and the rotation speed of the nip roller pairs 44a, 44b and 46a, 46b via the power amplification unit 96, and the output signal is output by the speed control unit 100. It is configured to be fed back to the third input terminal of the drive signal generation unit 94 via the.

On the other hand, a part of the output signal from the power amplification unit 96 is introduced into the error detection unit 102 as a monitor signal and introduced into the main body control unit 84 via the interface unit 88.

The apparatus for carrying out the method for controlling the sheet conveying system according to the present invention is basically constructed as described above. Next, its operation and effect will be explained.

First, the supply magazine 14 is mounted in the chamber 12 of the image reading device 10. In this case, in the supply magazine 14, for example, a plurality of stimulable phosphor sheets S on which radiation images of a subject such as a human body are accumulated and recorded are stacked and accommodated. Here, the main body control unit 84 outputs information such as the dimensions of the stimulable phosphor sheet S, the pre-reading process and the main reading process. In this case, the size of the stimulable phosphor sheet S is determined by reading a barcode attached to the end of the stimulable phosphor sheet S as identification information with a barcode reader arranged upstream of the image reading unit 26. It is detected based on the information. Here, the pre-reading step is a step of scanning the stimulable phosphor sheet S with excitation light to read radiation image information for reproducing a visible image for observation and interpretation (main reading step),
In order to optimally set the reading condition and / or the image processing condition in the main reading process, the stimulable phosphor sheet S is used.
The step of irradiating with excitation light of lower energy than the case of the main reading step and reading the outline of the radiation image information.

The output information output from the main body control unit 84 is passed through the interface unit 88 and the decoder unit 90 to a speed switching unit 92 for switching the conveying speed or the sandwiching speed of the stimulable phosphor sheet S in the main reading process, the pre-reading process, and the like. be introduced.

Therefore, the stimulable phosphor sheets S are taken out one by one from the supply magazine 14 under the action of the sheet-fed mechanism including the suction board 16, and the conveyor belt 18 and a plurality of rollers provided below the suction board 16 are provided. It is conveyed at high speed to the scanning mechanism 24 side via 20a to 20d and the roller 22. Then, when the stimulable phosphor sheet S enters the optical sensor 41 and the light from the light source 41a is blocked by the stimulable phosphor sheet S (third
(See FIG. A), the output signal of the light receiving element 41b is the main body control unit 8
Introduced in 4. Next, a drive start signal is introduced from the main body control unit 84 to the nip roller control unit 86 to the second input terminal of the drive signal generation unit 94. In this case, the drive signal generator 94
The pre-reading process has been introduced into the nip roller 44
The a and 46a are driven to rotate at high speed by a motor (not shown) via the power amplification section 96 and the solenoid 98, and the stimulable phosphor sheet S is carried into the reading section 26 while keeping the high speed (see FIG. 3b). . Therefore, in the pre-reading step, the image information carried on the stimulable phosphor sheet S can be read at high speed. In the pre-reading step, rough scanning may be performed in order to read the outline of the image, and the laser light 32 from the laser light source 30 has a large diameter.

This look-ahead information is provided by the light guide 40 and photomultiplier 42.
The image processing conditions are fetched by the main body control unit 84 via the, and optimum image processing conditions are set for exposure during main reading or image writing. During the pre-reading process, when the stimulable phosphor sheet S is conveyed to the point shown in FIG. 3c, the rollers forming the nip roller pair 46a and 46b move in a direction in which they are close to each other, and The body sheet S is nipped, and the stimulable phosphor sheet S is conveyed in the direction of arrow B to continue the pre-reading process (see FIG. 3d).

Next, when the stimulable phosphor sheet S enters the optical sensor 43, the output signal of the optical sensor 43 causes the main body controller 84, the nip roller controller 86, and the drive signal generator 94 to operate,
The first nip roller pair 44a, 44b is separated from the stimulable phosphor sheet S via the power amplifier 96 and the solenoid 98 (see FIG. 3e). At that time, the second nip rollers 46a, 4
The speed at which 6b reaches the nip of the stimulable phosphor sheet S, the speed at which the first nip roller pair 44a, 44b separates from the stimulable phosphor sheet S, and the rotation speed of the nip rollers 44a, 46b can be performed at high speed. is there. This is because the nip roller pair 44a, 44b and 44a, 46b are sandwiched in the pre-reading process,
A slight positional deviation of the stimulable phosphor sheet S caused by a high-speed operation related to separation and conveyance causes the pre-reading information to be used only as data for determining image processing conditions and the like in the main reading process, and an actual reproduced image. This is because there is no problem as it is not used as a signal that forms Then, when the pre-reading process is completed (see FIG. 3f), the nip roller pairs 44a, 44b and 44a, 46b are then rotated in the reverse direction as shown in FIG. (See FIG. 3 h). In this case, the first nip roller pair 44a and 44b are separated from each other in advance by a distance slightly shorter than the thickness of the stimulable phosphor sheet S. Then, when the conveyance in the reverse direction is completed, the second nip roller pairs 44a and 46b are separated from each other (see FIG. 3i).

Next, the main reading process is started. In this case, the output signal of the drive signal generator 94 is transmitted to the solenoid 98 via the power amplifier 96.
In order to precisely read the image information carried on the stimulable phosphor sheet S, the low-speed conveyance is performed. That is, the nip rollers 44a and 46a constituting the transport unit 28 are rotationally driven at a low speed, and the stimulable phosphor sheet S placed on the endless transport belt 47 is transported at a low speed in the sub-scanning direction (arrow B direction). To do. At that time, the reading unit 26 is driven again. In this case, the laser light emitted from the laser light source 30
32 is reflected by the mirror 34 to reach the galvanometer mirror 36, and the laser beam 32 is scanned on the sheet S under the swinging action of the galvanometer mirror 36. As a result, the stimulated emission light emitted from the stimulable phosphor sheet S is reflected directly or by the reflection mirror 38 to guide the light to the light guide 40.
The photomultiplier 42 converts the electric signal into an electric signal and sends the electric signal to the main body control unit 84.

Then, the main reading is performed by a series of steps shown in FIGS. In this case, the speed until the rollers forming the second nip roller pair 46a, 46b come close to each other to sandwich the stimulable phosphor S between the steps from FIG. 3j to FIG. 3k is speed control. The feedback action of the part 100 enables extremely high-speed control. That is, immediately after the operation of the pair of nip rollers 46a, 46b is started, a large current is supplied to the solenoid 98 for a short time to move the high speed to bring them closer to each other. The phosphor sheet S is moved at an extremely low speed so as not to cause the deformation, and the phosphor sheet S is clamped, and after the clamping, the clamp step is performed again with a steep slope until a current for obtaining a predetermined clamp force. By doing so, it is possible to eliminate the positional deviation of the stimulable phosphor sheet S and shorten the time required for the entire sandwiching process as much as possible. Similarly, the first step between the steps from FIG. 3k to FIG.
The speed until the rollers forming the nip roller pair 44a, 44b are separated from each other is controlled to be a low speed from a position where the accumulative phosphor sheet S is conveyed and sandwiched to a position just before being separated. The speed to return to the original position is controlled at high speed. For this reason, it is possible to extremely minutely suppress the load fluctuation applied to the motor (not shown) that rotationally drives the nip rollers 44a and 46a when they are separated from each other. When the stimulable phosphor sheet S reaches the position shown in FIG. 3m, the nip roller pair 46a, 46b releases the nipping action and is conveyed to the next step by the roller 52 and the conveyance belt 54. During the main reading process or the pre-reading process, the error detection unit 102 in the nip roller control unit 86 compares the monitor signal from the power amplification unit 96 with a predetermined signal change to determine whether or not there is a difference, If a difference is detected, the main body control unit 84 is notified of an abnormal operation of the solenoid 98,
The nip roller pairs 44a, 44b, 46a, and 46b serve to stop the carrying process.

Next, the stimulable phosphor sheet S reaches the erasing section 82 via the conveyor belt 72 and the rollers 74a and 74b. In the erasing section 82, a plurality of erasing light sources (not shown) are turned on. Therefore, the irradiation light erases the radiation image remaining on the stimulable phosphor sheet S. The stimulable phosphor sheet S from which the radiation image has been erased is conveyed by the conveyor belt 72 and rollers 74c to 74e.
It is conveyed to the upper part during the image reading and scanning via, and is accommodated in the receive magazine 80 while being displaced in the traveling direction via the roller 76 and the rollers 78a and 78b.

In the above embodiment, the nip roller holding speed and the separation speed are changed depending on the transport speed of the stimulable phosphor sheet S in the pre-reading step and the main reading step, but the stimulable phosphor sheet S detected as described above is changed. The conveying speed may be controlled according to the size, and the nipping speed and the separating speed of the nip roller may be changed.

[Effects of the Invention] As described above, according to the present invention, when reading or writing an image while nipping a sheet body such as a stimulable phosphor sheet carrying radiation image information using a nip roller, reading conditions and / or Alternatively, the speed at which the nip rollers are clamped, the speed at which the nip rollers are separated, and the speed at which the sheet body is conveyed by the nip rollers are set to predetermined speeds based on image processing conditions. Therefore, the accuracy of image reading can be maintained and the image processing can be performed in the shortest possible time, and thus the throughput of the apparatus can be significantly improved.

Although the present invention has been described with reference to the preferred embodiment, the present invention is not limited to this embodiment,
For example, the image processing speed can be further improved by using the method of the present invention even at the time of writing an image. Needless to say, various improvements and design changes can be made without departing from the scope of the present invention. is there.

[Brief description of drawings]

FIG. 1 is a schematic configuration explanatory view of an apparatus for carrying out the method of the present invention, FIG. 2 is an electric circuit block diagram of a nip roller control section incorporated in the apparatus for carrying out the method of the present invention, and FIGS. FIG. 7 is an operation explanatory view of a transport mechanism including a nip roller incorporated in an apparatus for carrying out the method of the present invention. 10 ... Image reading device, 24 ... Scanning mechanism 26 ... Image reading unit, 28 ... Conveying unit 41 ... Optical sensor, 41a ... Light source 41b ... Light receiving element, 43 ... Optical sensor 43a ... Light source, 43b ... Light receiving element 44a, 44b, 46a, 46b ... Nip roller pair 47 ... Conveyor belt, 84 ... Main body control section 86 ... Nip roller control section, 92 ... Speed switching section 94 ... Drive signal generation section, 96 …… Power amplification section 98 …… Solenoid, 100 …… Speed control section 102 …… Error detection section S …… Accumulative phosphor sheet

Claims (3)

[Claims] 1. A main scanning is performed on a sheet body by a light beam deflected in a one-dimensional direction, and the sheet body is arranged with a main scanning position by the light beam being sandwiched at intervals shorter than the length in the conveying direction. In the method of nipping and conveying the sheet body by the first and second roller pairs in the sub-scanning and two-dimensionally scanning the sheet body, the leading end of the sheet body nipping and conveyed by the first roller pair is the second Detecting the approach to the roller pair and controlling the approach speed at which the rollers forming the second roller pair reach the holding position of the sheet body in response to the conveying speed of the sheet body, and / or the first roller. Detecting that the rear end of the sheet body approaches the pair, and controlling the speed at which the rollers forming the first roller pair are separated from the nipping position of the sheet body in accordance with the conveying speed of the sheet body. Featuring Control method for sheet conveying system. 2. The method according to claim 1, wherein the approaching speed at which the rollers forming the second roller pair reach the nipping position of the sheet body until the rollers reach a predetermined approaching range. Is a high speed, and is controlled to be a low speed immediately before the rollers sandwich the sheet, and a control method of the sheet conveying system. 3. The method according to claim 1 or 2, wherein the rollers forming the first roller pair are separated from each other by a separation speed until the rollers return to the original separation position. A control method for a sheet conveying system, comprising controlling a speed from a sandwiching position to a position immediately after separation to a low speed, and a speed from immediately after separation to returning to a separation original position to a high speed.