JPH03259843A - Sheet conveying mechanism - Google Patents

Abstract

PURPOSE:To enable the pinching and opening of a sheet without performing a mechanical roller movement by setting a roller down to a variable diametral roller variable in the diameter, in a sheet conveying mechanism using a light beam scanner. CONSTITUTION:A roller body 40 is hollow and at least a part of it is made up of an elastic body 58 of rubber or the like, while a fluid of air or the like flows in or out of the inside and the elastic body 58 is expanded or contracted, thereby constituting a variable diametral roller 26 variable in the diameter. Next, before those of various sheets of recording materials including a sensitive material or the like and an accumulable phosphor sheet body, etc., are taken thereinto, the diameter of this variable diametral roller 26 is made smaller in advance, and after the sheet body is conveyed to a pinchable position vt the roller, the diameter of this roller 26 is made larger, holding the sheet body or a conveyed system in between.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a sheet conveyance mechanism that is applied to an image recording device, an image reading device, etc., and which conveys a sheet while being held between rollers.

<Prior art> When a certain type of phosphor is irradiated with radiation (X-rays, α-rays, β-rays, γ-rays, electron beams, ultraviolet rays, etc.), a part of this radiation energy is accumulated, and after this, It is known that when phosphors are irradiated with excitation light such as visible light, they exhibit stimulated luminescence depending on the accumulated energy. It is called an exhaustible phosphor).

Using this stimulable phosphor, radiation image information of a subject such as a human body is recorded on a sheet having a layer of stimulable phosphor (hereinafter referred to as a stimulable phosphor sheet). is scanned two-dimensionally with excitation light such as a laser beam to generate stimulated luminescence light, and this stimulated luminescence light is read photoelectrically to obtain an image signal, and based on this image signal, photographic light-sensitive materials, etc. The present applicant has already proposed a radiation image information recording and reproducing system that outputs a radiographic image of a subject as a visible image to a display device such as a CRT or a recording material (Japanese Patent Laid-Open Nos. 55-12429 and 56-1999). 11395, etc.).

In such a radiation image information recording and reproducing system,
The radiation image information recorded on the stimulable phosphor sheet is read mainly by using an optical deflector such as a galvanometer mirror to emit excitation light (laser beam) of a constant intensity from an excitation light source such as a He-Ne laser. Reflected in the scanning direction
By deflecting the stimulable phosphor sheet and moving the stimulable phosphor sheet relative to the excitation light by transporting the stimulable phosphor sheet in a sub-scanning direction substantially perpendicular to the main scanning direction, as a result, By scanning this stimulable phosphor sheet two-dimensionally with excitation light, stimulated luminescence light corresponding to the image information accumulated and recorded at the excitation light irradiation position of the stimulable phosphor sheet is generated. This is done by condensing the exhausted light and making it enter a photomultiplier tube, where it is photoelectrically converted into an electrical signal and processed.

By the way, in various devices such as image reading devices such as radiation image information reading devices, light beam scanning devices such as image recording devices, etc., a sheet body such as a stimulable phosphor sheet is fixed at a predetermined position. Conventionally, a belt conveyor with suction is used as a conveyance mechanism that conveys the sheet at a constant speed, and the suction suctions and fixes the sheet to accurately convey it in a predetermined position in the sub-scanning direction. was. However, this method of sub-scanning conveyance uses a suction box, which increases the size of the device, and also requires a vacuum generator and its control device, which increases the cost of the device.

On the other hand, as a small and inexpensive conveyance mechanism for sheet bodies, two pairs of rollers are arranged at intervals shorter than the length of the sheet body to be scanned in the conveyance direction, and these two pairs of rollers A method of nipping and conveying a sheet body at a predetermined position (hereinafter referred to as twin nip), or a method of pressing two rollers arranged at a distance shorter than the length of the scanned body in the conveyance direction against the support drum. A method is known in which the sheet body is held and conveyed between the two.

<Problems to be Solved by the Invention> However, in a conveyance mechanism that applies nipping by such rollers, when the sheet to be scanned is nipped by the drive rollers or separated from the driving rollers, an impact is applied to the sheet. In this case, the sheet body cannot be conveyed smoothly at a constant speed because of the fluctuation in the conveyance load. Therefore, when this is applied to a light beam scanning device such as the above-mentioned image reading device or image recording device, for example, this impact and load fluctuation will have a negative effect on the sub-scanning conveyance of the sheet, allowing accurate image reading. There is a problem that it is not possible to perform image recording.

Also, in equipment that uses support drums, see! - Since the sheet conveyance path is not a straight line, there is also the problem that conveyance errors are likely to occur in which the sheet body cannot be held between the support drum and the rollers.

In response to such problems, the present applicant has
In Japanese Patent Application Laid-Open No. 064-4, a conveyance mechanism for a sheet body in which a pair of rollers can be opened and closed by an actuator is disclosed.
Japanese Patent Laid-Open No. 7241 discloses a sheet conveyance mechanism in which one roller is movable relative to the other under the action of an actuator through an elastic member, and Japanese Patent Application Laid-open No. 167-1987 describes
Publication No. 150 discloses a light beam scanning device that performs scanning between two pairs of rollers, and a conveyance mechanism that releases the sheet by the pair of rollers on the upstream side when the sheet is sandwiched between the pair of rollers on the downstream side. Disclosed. Furthermore, in JP-A-63-193762, when a conveyance path is curved downstream of the light beam scanning position, the light beam scan is performed when a pair of rollers disposed on the curved conveyance path nip a sheet. In order to prevent an adverse effect on the light beam, a conveying mechanism for the sheet body is disclosed in which the grip between the pair of rollers is released while the light beam is scanning the sheet body.

According to the above-mentioned conveyance mechanism for each sheet body, it is possible to significantly reduce the load fluctuation and impact when the sheet body is pinched and separated by the conveyance rollers, and it is possible to convey the sheet body smoothly and accurately at a constant speed. It can be carried out.

Here, if the rollers in each of the above-mentioned conveyance mechanisms are moved rapidly, it will cause shocks and vibrations, as well as load fluctuations in the conveyance of the sheet, which will also have an adverse effect on the sub-scanning. There is also the possibility of damaging the surface.

Therefore, when moving the moving roller up and down, especially when lowering it, the moving roller is lowered at a relatively fast speed until just before it contacts the sheet body, and then until the sheet body and the moving roller come into contact and are pinched. It is necessary to control the descent at extremely low speed.

Therefore, in order to move the roller up and down, a moving device capable of precisely moving the roller and a control device thereof are required, and the sheet conveying device becomes complicated and expensive. Furthermore, since the movement of the moving roller is performed by a mechanical mechanism, wear and deterioration of the drive section cannot be avoided, which also leads to an increase in running costs.

Furthermore, since the movement of the rollers is performed by a mechanical mechanism, even if the movement of the rollers is controlled as described above, it is impossible to avoid shocks and vibrations due to vertical movement, fluctuations in conveyance load, etc. There are also problems such as image recording and reading errors caused by this.

An object of the present invention is to solve the problems of the prior art as described above, and by making it possible to clamp and release the sheet body without mechanically moving the rollers, it is possible to move the sheet body at a constant speed without complicated control. An object of the present invention is to provide a sheet body conveyance mechanism that can smoothly convey a sheet body.

Means for Solving the Problems> In order to achieve the above object, the present invention provides a sheet body conveying mechanism that conveys a sheet body while being held between rollers.
It is an object of the present invention to provide a sheet conveying mechanism characterized in that the roller is a variable diameter roller whose diameter is variable.

In addition, the variable diameter roller has a roller body that is hollow and has a small diameter (partly formed of an elastic body, and when fluid flows in and out of the roller, the elastic body expands and contracts, making the diameter variable). is preferred.

Further, in the variable diameter roller, at least a portion of the roller main body in the axial direction is formed of an elastic body, and when pressed and pulled from both ends in the axial direction, the elastic body expands and contracts, thereby changing the diameter. is preferable.

Further, it is preferable that the variable diameter roller is a free roller.

<Operation of the Invention> The sheet body conveying mechanism of the present invention includes a variable diameter roller whose diameter is variable, preferably a roller body that is hollow and at least partially made of an elastic body such as rubber, and that has air inside. A variable diameter roller whose diameter is variable by expanding and contracting the elastic body by flowing in and out a fluid, or at least a part of the roller body in the axial direction is formed of an elastic body,
A variable diameter roller whose diameter can be varied by expanding and contracting the elastic body by compressing or pulling it from both ends is used.

In such a sheet conveyance mechanism of the present invention, the diameter of the variable diameter roller is made small before various sheet bodies such as recording materials such as photosensitive materials and stimulable phosphor sheets are carried in. After the sheet body is conveyed to a position where it can be pinched by the rollers, it is possible to increase the diameter of the rollers to pinch the sheet body to be conveyed. Therefore,
There is no impact or load fluctuation due to the pinching and separation of the sheet (it allows for smooth conveyance of the sheet at a constant speed, and even when applied to light beam scanning devices such as radiation image information reading devices). Good image reading and recording can be performed by accurate, smooth, and even sub-scanning.

In addition, when conveying the object to be scanned, for example, if the diameter of the roller is variable by the inflow and outflow of the fluid, air or the like is introduced into the variable diameter roller, and the elastic body By inflating the diameter of the roller, the object to be scanned can be reliably held and conveyed.
After the object to be scanned is transported to a predetermined position, the air inside the variable diameter roller is removed (by which the diameter of the roller is reduced,
It is possible to release the object to be scanned.

Therefore, there is no shock or vibration associated with the vertical movement of the rollers and the clamping/release of the scanned object, unlike the conventional sheet conveyance mechanism that uses a mechanical mechanism of vertical movement of rollers to clamp and release the sheet. , it is possible to accurately convey the sheet body without conveyance unevenness caused by this.

In addition, there is no need for complicated devices or controls associated with clamping and releasing the sheet body, there is no wear of the device due to vertical movement of the rollers, there is no staining due to oil, etc., and by applying the sheet conveyance mechanism of the present invention, , it is possible to realize various devices such as a light beam scanning device that is low in both cost and running cost.

<Embodiments> Hereinafter, a sheet conveyance mechanism according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

FIG. 1 shows a schematic perspective view of an example of a light beam scanning device to which the sheet conveyance mechanism of the present invention is applied.

The illustrated light beam scanning device 10 is a light beam scanning device applied to an image recording device, an image reading device, etc., and includes recording materials such as photosensitive materials, stimulable phosphor sheets, manuscripts such as photographs and printed materials, etc. While conveying the scanned object A, which is a sheet body, in the sub-scanning direction shown by the arrow X, the light beam 12 is deflected in the main scanning direction shown by the arrow y, and the light beam 12 is irradiated onto the object A to be scanned, and the object A is scanned two-dimensionally.

1 2 Such a light beam scanning device 10 basically includes a light source 16 for the light beam 12 , a galvanometer mirror 18 , an fθ lens 20 , a down mirror 22 , and a sub-scanning conveyance device 24 . Here, the sub-scanning conveyance device 24 applies the sheet body conveyance mechanism of the present invention.

The light source 16 is a light source such as a He-Ne laser or an LD (laser diode) that emits a light beam, and emits the light beam 12 toward the galvanometer mirror 18 .

The galvanometer mirror 18 reflects this light beam 12 and deflects it in the main scanning direction (arrow y direction).

The light beam 12 deflected in the main scanning direction by the galvanometer mirror 18 has its focus adjusted by an fθ lens 20 so as to converge on the object A to be scanned, and is then lowered downward by a drop mirror 22 to irradiate it. position 1
4, an image is formed on a scanned object A that is sub-scanned and conveyed in the direction of arrow X by the sub-scanning conveyance device 24.

The sub-scanning conveyance device 24 applied to the illustrated light beam scanning device 10 applies the above-mentioned twin nip method using two pairs of rollers arranged with the irradiation position 14 (scanning line) in between. , basically a roller pair 30 consisting of a variable diameter roller 26 and a drive roller 28, and a variable diameter roller 3.
2 and a drive roller 34, and a sensor 38 that detects the position of the object to be scanned.

Here, this sub-scanning conveyance device 24 is based on the sheet body conveyance mechanism of the present invention that applies variable diameter rollers 26 and 32 whose diameters are variable, and in the sub-scanning conveyance device 24 of the illustrated example, In a preferred embodiment, the variable diameter rollers 26 and 32 have hollow roller bodies, and at least a portion thereof is formed of a stretchable elastic body such as rubber. The diameter of the roller can be changed by expanding and contracting the roller. Note that the variable diameter rollers 26 and 32
is a free roller, drive rollers 28 and 34 are drive rollers, and a rotational drive source (not shown) is connected to at least one of drive rollers 28 and 34.

FIG. 2a is a diagram conceptually showing a cross section of the variable diameter roller 26 in the main scanning direction, and FIG. A diagram conceptually representing a cross section in the main scanning direction of the state in which the image is displayed is shown.

It should be noted that the variable diameter roller 32 has the same configuration as the variable diameter roller 26, so the same members are given the same numbers and the explanation thereof will be omitted.

The variable diameter roller 26 basically includes a hollow roller body 40 made of a stretchable elastic material such as rubber or resin, and supports 4 that support this roller body 40 at both end portions in the main scanning direction.
2 and 44.

In the illustrated example, the roller body 40 is made of a stretchable elastic material such as rubber or resin, and has a hollow cylindrical shape with an opening 46 formed in one end surface, and ribs 48 are formed around the opening 46. However, a convex portion 50 is formed on the other end surface.

The stretchable elastic body applied to the present invention includes various types of rubber, which when applied to the roller body 40, can be expanded and contracted into a desired shape by flowing fluid in and out of the body. Any of various known elastic bodies can be used.

The supports 42 and 44 support the roller body 40 by fitting the ribs 48 and convex portions 50 of the roller body 40, respectively. Nozzle 5 for inflow and outflow
2, a support shaft 54 is also formed on the support body 44.
Note that the method of fixing each support and the roller body 40 is not limited to the above example, and instead of providing ribs or convex portions on the elastic part, the support is fixed by using an adhesive on the end surface of the roller body 40. It is also possible to use a method of adhering.

The variable diameter roller 26 having a configuration as shown in FIG.
A support shaft 54 is rotatably supported by a side plate (not shown) or the like by being supported via a bearing or the like, and an air outlet means is connected to the nozzle 52 via a coupling or the like.

In other words, the variable diameter roller 26 is normally thin as shown in FIG. 2a, but when it grips the scanned object A, air is released from the nozzle 52 as shown in FIG. 2b. By flowing in and being pressurized from inside, the roller main body 40 formed of an elastic body expands and becomes thicker in diameter.
As shown in the figure, it becomes possible to nip and convey the scanned object A together with the drive roller 28.

There is no particular limitation on the air guide means that can be applied, and any known method can be applied, such as a method of causing air to flow in and out of the roller body 40 using a compressor, a solenoid valve, or the like. Further, a valve may be provided in the nozzle 52 to control the inflow and outflow of air. Furthermore, any known coupling that connects the nozzle 52 and the air inflow/outflow means can be used.

Expansion of the roller body 40 of the variable diameter roller 26 (
The clamping force of the scanned object A between the roller body 40 and the drive roller 28 due to the change in the roller diameter may be such that the variable diameter roller 26 lightly presses the drive roller 28 from above, and the variable diameter roller 26 Followed by 28, scanned object A
It is sufficient if the material can be reliably pinched and conveyed. Further, when the variable diameter roller 26 expands, the roller main body 40 is highly flexible, and the surface shape thereof follows the surface shape of the drive roller 28 when the object to be scanned A is being conveyed. It's okay.

In the variable diameter roller 26, as a method for uniformly expanding the roller body 40 as shown in the illustrated example, for example, the thickness of the elastic body constituting the roller body 40 may be made different depending on the location, so that the expansion of the elastic portion is prevented. Examples include methods for making it uniform.

The variable diameter roller Ll applied to the present invention is not limited to the example shown in FIGS. 2a and 21, and has a wiping hole 55 for fluid such as air as shown in FIG. 3. A structure may be adopted in which the support shaft 56 passes through the roller main body 57 formed of an elastic body, and the entire roller main body 57 is supported by the support shaft 56.

In addition, in the sheet conveyance mechanism of the present invention, the shape of the elastic body applied to the roller body (the diameter of the roller body) is not limited to the above example, and the roller body expands into a curved shape. In addition, when the elastic body expands, it may have a stepped roller shape that has a plurality of continuous protrusions in the circumferential direction (axial direction), an embossed shape that has many protrusions formed on the surface of the roller body, etc. , the elastic body may be partially expanded (protruded).

Furthermore, as shown in FIG. 4a, for example, the entire roller body is not made of an elastic body, but elastic portions 58, 58 made of an elastic body.
,..., the fixed part 60.6 whose shape does not change
0, . A configuration in which the scanning body A is pinched and conveyed is also suitably exemplified.

The method of changing the diameter of the variable diameter roller is not limited to the method of pressurizing the inside; in the normal state shown in FIG. It may be configured such that when it is transported, the pressure is returned to normal and the diameter shown in FIG. 2b is increased.

Further, the fluid used to change the diameter of the variable diameter roller is not limited to the above-mentioned air, and any of various gases and liquids such as water can be used.

The variable diameter roller applied to the present invention is one in which the roller body as described above is formed of a hollow body, and the diameter is made variable by expanding and contracting the elastic body by letting fluid flow in and out of the roller body. As shown in the variable diameter roller 66 shown in FIG. elastic part 6
8, 68... are arranged alternately in the axial direction and pressed in the direction of arrow a as shown in Fig. 5b.
A configuration in which the diameter of 8.68... is changed is preferably applied. The variable diameter roller of this form is formed in advance so as to be in the state shown in Fig. 5b, and when the sheet body is not being held, it is pulled in the direction opposite to the direction of arrow a, so that it is in the state shown in Fig. 5a. It can be used as a state (or as a configuration).

By applying the above-mentioned sub-scanning conveyance device 24 according to the sheet conveyance mechanism of the present invention, the illustrated light beam scanning device 10 can transport the object A to be scanned, like a conventional light beam scanning device. This is done by expanding and contracting the roller body 40, rather than holding and releasing the object A to be scanned by a mechanical mechanism such as an actuator.
Accurate light beam scanning is possible without shocks, vibrations, etc. associated with clamping and opening, and with no accompanying deviations in sub-scanning conveyance or light beam irradiation position. Moreover, since no mechanical mechanism is applied to the sub-scanning conveyance of the scanned object A, there is no wear of mechanical parts, no oil stains, etc., and maintenance efficiency and running costs can also be improved.

The sensor 38 is for detecting when the object to be scanned A has been carried to a predetermined position. The maximum diameter of the variable diameter rollers 26 and 32 is changed with the passage of time after passing the sensor 380, and the scanned object A is held and released by the pair of rollers 30 and 36. The sensor 38 to be applied is not particularly limited, and any of various known types such as an optical type and a mechanical type can be applied. Further, the arrangement position and number are not limited to the illustrated example.

FIGS. 6a to 6d conceptually illustrate the operation of the above-described sub-scanning conveyance device 24.

As shown in FIG. 6a, before the object A to be scanned is carried into the sub-scanning conveyance device 24, the variable diameter rollers 2G and 32
The roller body 40 is in a contracted state, and both are separated from the drive rollers 28 and 34.

When the scanned object A is conveyed in the direction of the arrow X and passes over the sensor 38 for a predetermined period of time when it can be held between the roller pair 30, air flows into the variable diameter roller 26.
The roller main body 40 expands and the diameter of the variable diameter roller 26 becomes thicker, and the object A to be scanned is conveyed while being held by the pair of rollers 30 (FIG. 6b).

When the object to be scanned A is further conveyed and a predetermined period of time has elapsed, air is subsequently introduced into the variable diameter roller 32, and the roller body 40 expands to increase the diameter of the variable diameter roller 32, as shown in FIG. 6C. As shown in , the object A to be scanned is conveyed in the sub-scanning direction by both roller pairs 30 and 36 in the direction of the arrow X, while being conveyed in the main scanning direction (direction of the arrow y) as described above.
The irradiation position 14 is two-dimensionally scanned by the light beam 12 which is deflected by the light beam 12 .

In the illustrated example, the object to be scanned A has been scanned by the light beam 12 even before being held between the pair of rollers 36 at the time when its leading end is conveyed to the irradiation position 14 .

Furthermore, when the object A to be scanned is conveyed and its rear end reaches the position of the roller pair 30, the air inside the variable diameter roller 26 is removed, and the roller main body 40 is contracted and the roller pair is 30 is released, and similarly, when the rear end of the scanned object A comes to the position of the roller pair 36, the air inside the variable diameter roller 32 is removed and the roller pair 32
The clamping of the object A to be scanned is released.

Note that the sheet conveyance mechanism of the present invention is not limited to application to sandwich conveyance using the pair of rollers as described above, but includes a support drum that supports the scanned object A at the light beam irradiation position, and a Of course, it is also suitably applicable to a method in which the object to be scanned 34A is nipped and conveyed by two nip rollers that are pressed against this support drum with the position (scanning line) in between. Further, in this case, the maximum diameter may be variable for either the support drum or the nip roller.

Such a sheet conveyance mechanism of the present invention can be used in image recording devices such as printers and copying machines, and image reading devices such as radiation image information reading devices by arranging a condensing optical system (not shown) near the scanning line of the light beam 12. The present invention is also suitable for use in light beam scanning devices such as the above-mentioned JP-A-63-193762, and conveyance means before and after the sub-scanning conveyance device of the light beam scanning device, such as the sheet conveyance mechanism disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 63-193762. Applicable. Furthermore, it can be suitably applied to a recording fee withdrawal roller in a copying machine, an image forming apparatus, etc., a stimulable phosphor sheet in a conveying apparatus, an image reading apparatus, and a document conveying apparatus.

Although the sheet conveyance mechanism of the present invention has been described in detail above, the present invention is not limited thereto, and it goes without saying that various changes and improvements may be made without departing from the gist of the present invention. It is about.

<Effects of the Invention> As explained in detail above, according to the sheet conveyance mechanism of the present invention having the above-mentioned predetermined configuration, rollers like the conventional sheet conveyance mechanism are not used for pinching and releasing during sheet conveyance. Since the mechanical mechanism of vertical movement is not applied, there is no need for complex devices or controls such as a sophisticated actuator drive mechanism that moves the rollers up and down to clamp and release the sheet. There is no wear of the device, there is no oil staining, etc., and when applied to various devices, it is possible to realize a device that is low in cost and running cost.

Moreover, since the rollers do not move, there is no shock or vibration caused by the up and down movement of the rollers or by the pinching and release of the sheet. be able to.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing an example of a light beam scanning device to which a sheet conveyance mechanism according to the present invention is applied. FIG. 2a is a sectional view conceptually showing a variable diameter roller applied to the light beam scanning device shown in FIG. 1. FIG. FIG. 2b is a sectional view conceptually showing when the variable diameter roller shown in FIG. 2a is expanded. FIG. 3 is a sectional view conceptually showing another example of the variable diameter roller applied to the sheet conveyance mechanism of the present invention. FIGS. 4a and 5a are front views conceptually showing other examples of variable diameter rollers applied to the sheet conveyance mechanism of the present invention, respectively. FIGS. 4b and 5b are front views conceptually showing the variable diameter roller shown in FIGS. 4a and 5a, respectively, when expanded. 6a to 6d are diagrams conceptually showing the operation of the sub-scanning conveyance device of the light beam scanning device shown in FIG. 1. FIG. Description of symbols 10...Light beam scanning device, 12...Light beam, 14...Irradiation position, 16...Light beam light source, 18...Galvanometer mirror 20...Fθ lens, 22... - Lowering mirror 24... Sub-scanning conveyance device, 26.32.66... Variable diameter roller, 28.34...
・Drive roller, 30.36, 102, 104...Roller pair, 38...
-Sensor, 40.57... Roller body, 42.44... Support, 46... Opening, 48... Rib, 7 8 50... Convex portion, 52... Nozzle, 54. 56... Support shaft, 55... Wiping hole 58.68... Elastic part, 60.70... Fixed part, A... Scanned object

Claims (1)

[Claims] (1) A sheet conveying mechanism that conveys a sheet by holding it between rollers, characterized in that the roller is a variable diameter roller whose diameter is variable.