JP4025989B2 - Conveying mechanism and image forming apparatus for sheet-like object - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transport mechanism for transporting a sheet-like transport target and an image forming apparatus including the transport mechanism.
[0002]
[Prior art]
Conventionally, in an image forming apparatus for forming an image on a heat-developable photosensitive film for medical image recording, a suction cup pickup method by vacuum suction has been adopted to transport a film laminated on a tray of a supply unit (for example, JP 2000-275749 A). In order to make the transport mechanism more compact, it is possible to apply a known transport mechanism in which a friction force is applied to the film by the pressing force of the transport roller and the film is fed by a rotational motion and then transported by a pair of nip rollers. An example of such a conventional film transport mechanism is shown in FIG.
[0003]
In the conventional example of FIG. 5, the transport roller 91 that is in contact with the surface BC of the film F laminated in the tray T with a predetermined pressing force P1 rotates in the rotation direction r, whereby the uppermost film F is paired with a pair of nip rollers. It sends out to the 92,93 side. Then, the film F is transported in the transport direction H while being sandwiched between the nip rollers 92 and 93 while applying the nip force P2 from the drive nip roller 93 side to the driven nip roller 92 side.
[0004]
When the film is transported as described above, the uppermost film F and the one or two films below it may be sent out by the transport roller 91 and transported by the nip rollers 92 and 93, so that the nip roller 93 is provided with a torque limiter. Consists of reversible rollers. When the torque of the nip roller 93 increases when a plurality of films are sandwiched between the pair of nip rollers 92 and 93, the torque limiter detects that the nip roller 93 rotates in the reverse direction, and the excessively conveyed film is returned to its original state.
[0005]
A large number of heat-developable photosensitive films are laminated and packaged in a barrier bag in a deaerated state before shipment. Further, a matting agent is disposed on the front surface BC side of the film F, and an emulsion for recording an image is coated on the back surface EC of the film F to form an emulsion surface. The film is laminated so that the front surface BC and the back surface EC face each other, and the protrusions of the matting agent arranged on the front surface BC side make it difficult for the films to stick to each other. If the film is kept stored, the degree of vacuum between the films increases, and the adhesion between the films proceeds. As a result, the force required to separate the films one by one increases.
[0006]
Further, when the uppermost film F is transported to the film below it while being pressed by the transport rollers 91 and the nip rollers 92 and 93 with predetermined forces P1 and P2 during film transport, particularly for the film separation as described above. Since the nip force by the nip rollers 92 and 93 increases and the matting agent on the front surface BC moves while rubbing the emulsion surface of the back surface EC, scratches may occur on the back surface EC of the film F. May be affected.
[0007]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a transport mechanism and an image forming apparatus capable of preventing a transported body from being damaged and transporting stably when separating and transporting stacked sheet-shaped transported bodies. And
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a transport mechanism according to the present invention comprises: a transport roller that is pressed against a sheet-shaped transported body and rotated and driven to rotate; and a transported transported body that feeds the transported body. A friction member that contacts the intermediate member, and a driven rotatable intermediate roller disposed so as to sandwich the conveyed member between the friction member while urging the conveyed member, and the conveyed member that has passed through the intermediate roller Is characterized in that the friction member is inclined in the transport direction of the transported body so as to be bent by contacting at the tip.
[0009]
According to this transport mechanism, the transported body sent out by the transport roller is transported while receiving an appropriate frictional force while being urged by the friction member by the intermediate roller. When the roller passes through the intermediate roller, the tip of the roller comes into contact with the inclined region of the friction member and bends, so that the plurality of transported bodies can be separated even when they pass through the intermediate roller. Therefore, since it can be separated without using a conventional reverse rotation roller with a torque limiter, it is possible to prevent damage to the transported body.
[0010]
In the transport mechanism, the friction member may be inclined in at least two stages, and a region where the tip abuts may be inclined more greatly than a region where the intermediate roller is disposed. As a result, the object to be conveyed is urged by the intermediate roller in a relatively sloping area, so that the conveyance is stable, and the tip abuts in a relatively steep area, so that it is easily bent and easily separated. It becomes.
[0011]
Further, the intermediate roller is disposed immediately before a region where the leading ends abut so that the plurality of transported members are separated at the tip when the plurality of transported members pass through the intermediate roller. It is preferable.
[0012]
Further, it is preferable to provide a return roller that reversely rotates so as to return the transported body when a plurality of transported bodies pass the intermediate roller, thereby returning the transported body that has been transported excessively. be able to.
[0013]
In addition, it is preferable that a gap between the intermediate roller and the friction member is controlled to be a constant amount so as to limit the number of sheets to be transported by the intermediate roller.
[0014]
Moreover, it is preferable that the said to-be-conveyed body is comprised so that it may send out with the said conveyance roller in the state in which several sheets were laminated | stacked.
[0015]
Further, the transport force by the transport roller with respect to the transported body is greater than the separating force with respect to the transported body in the region where the tip abuts, and is preferably more than twice the separating force. Thereby, a to-be-conveyed body can be conveyed stably and isolation | separation can be performed reliably. Here, the separation force is the sum of the impact force when the tip of the transported body comes into contact with the inclined region of the friction member and the friction force received from the friction member.
[0016]
Further, the transport roller is made of an elastic material that is pressed against the transported body with a pressing force of 75 gf / mm ² or less, has a rubber hardness of 20 ° or more, and has a dynamic friction coefficient of 2 or more with respect to the transported body. Preferably, it is configured.
[0017]
Further, it is preferable that the friction member is made of an elastic material that is inclined by 23 ° or more with respect to a horizontal direction in a region where the tip contacts, and has a dynamic friction coefficient of 2 or more with respect to the transported body.
[0018]
Moreover, it is preferable that the said to-be-conveyed body is conveyed with the conveyance speed of 20 mm / sec or less by the said conveyance roller.
[0019]
Further, a sensor for detecting the number of the transported bodies can be arranged on the downstream side of the intermediate roller, and when the extra sheets are transported, the extra transported bodies can be returned by the return roller. In this case, when the transported body cannot be detected by the sensor within a predetermined time from the start of the transported body by the transport roller, a mechanism for returning the transported body (for example, a mechanism that reversely rotates the transport roller) is provided. It is preferable to further provide.
[0020]
An image forming apparatus according to the present invention includes the above-described transport mechanism, and forms an image on the transported transported body. Since the recording medium such as a film and recording paper can be stably conveyed by the above-described conveying mechanism, image formation can be performed stably, and damage to the recording medium can be prevented, so that the image quality formed on the recording medium can be improved. Can be maintained.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view schematically showing a film transport mechanism according to an embodiment of the present invention, and FIG. 2 is a side view showing a friction member of FIG.
[0022]
As shown in FIG. 1, the film transport mechanism 10 includes a transport roller 11 that is pressed against the uppermost film F <b> 1 of the film F laminated on the tray T, and a planar shape that guides the film F <b> 1 fed from the transport roller 11. The guide member 17, the friction member 14 formed on the guide member 17 and transported while the film F 1 is in contact, and the intermediate member urged toward the friction member 14 while sandwiching the film F 1 between the friction member 14. A roller 12 and a return roller 13 for returning the excess film when a plurality of films pass through the intermediate roller 12 to the original by reverse rotation are provided.
[0023]
The film F, which is a transported body, is a photosensitive film such as a photothermographic material. A large number of films F are stacked on the tray T, and are sequentially transported from the uppermost film F1. Film F uses PET or the like as a base material, a matting agent is disposed on the front side of FIG. 1, and the back side of FIG. 1 of film F is an emulsion surface coated with an emulsion for image recording. The tray T is raised and lowered by a horizontal raising / lowering mechanism (not shown), and is raised when the number of laminated films is reduced by film conveyance so that the uppermost film is always at a certain height.
[0024]
The transport roller 11 is made of an elastic material having a rubber hardness of 20 ° or more and a dynamic friction coefficient of 2 or more with respect to the film, and a motor (not shown) while being pressed against the film F1 with a pressing force S1 of 75 gf / mm ² or less. ). By the rotation of the transport roller 11, the film F1 can receive a transport force S2 of 1 kgf or more. The transport roller 11 can be manufactured by powder molding using, for example, an elastomer-based thermoplastic resin, and can be formed by adjusting the surface roughness so as to obtain a predetermined dynamic friction coefficient.
[0025]
As shown in FIG. 1, the transport roller 11 is provided on the tip side of an arm 11a extending from the rotation shaft 11b. The pressing force S1 of the conveying roller 11 can be obtained from the moment of the arm 11a based on the weight of the conveying roller 11 or the length of the arm 11a. For example, the pressing force S1 is adjusted by adjusting the own weight of the conveying roller 11. The moment is adjusted to 75 gf / mm ² or less.
[0026]
The intermediate roller 12 is made of a resin material such as POM, and the film fed from the transport roller 11 is sandwiched between the friction members 14 and further rotated in the transport direction H while being driven to rotate. The intermediate roller 12 is biased in a substantially vertical direction toward the friction member 14 by a biasing member 12a such as a coil spring, but the pressing force is less than 75 gf / mm ² . The gap of the slit between the intermediate roller 12 and the friction member 14 is adjusted to be about 1.5 to 2 films, and the slit separation prevents conveyance of 3 or more films. The slit gap between the intermediate roller 12 and the friction member 14 for slit separation is managed to be a constant amount by a gap gauge or the like at the time of manufacture, for example, and is appropriately managed at the time of maintenance or the like. You can adjust it.
[0027]
The friction member 14 is made of an elastic material such as an elastomer having a dynamic friction coefficient of 2 or more with respect to the film, and is inclined in two stages as shown in FIGS. A first inclined region 15 that is inclined relatively gently toward the side and a second inclined region 16 that is inclined relatively steeply from the end of the first inclined region 15 are included.
[0028]
As shown in FIG. 2, the first inclined region 15 of the friction member 14 is inclined at the inclination angle θ1 with respect to the horizontal direction, the second inclined region 16 is inclined at the inclination angle θ2, and the inclination angle θ2 is the inclination angle θ1. Is greater than 23 °. For example, when the inclination angle θ2 is set to 23 °, the inclination angle θ1 can be set to 12 °.
[0029]
As shown in FIGS. 1 and 2, the intermediate roller 12 is disposed in the first inclined region 15 of the friction member 14 and is disposed immediately before the second inclined region 16. Further, the return roller 13 is disposed in the vicinity of a transition portion between the first inclined region 15 and the second inclined region 16 on the downstream side of the intermediate roller 12.
[0030]
When the film is conveyed, the friction member 14 is urged by the intermediate roller 12 in the first inclined area 15 having a relatively gentle inclination. Therefore, since the dynamic friction coefficient is large, the film is conveyed by receiving a relatively large frictional force. Since the film is stable and receives a relatively large frictional force in the second inclined region 16 which is stable and has a relatively steep inclination, the film is easily bent and easily separated. The leading edge of the film receives the impact force when the leading edge of the film comes into contact with the second inclined region 16 and the friction force from the friction member 14, and the sum of these impact force and friction force is a plurality of sheets. The contact separation force S3 (FIG. 3B) for separating the film is obtained, and is adjusted to be smaller than the conveyance force S2 by the conveyance roller 11.
[0031]
Next, the film transport and separation operations of the film transport mechanism 10 of FIGS. 1 and 2 will be described with reference to FIG. FIGS. 3A to 3C are side views showing transport and separation operations by the film transport mechanism 10.
[0032]
First, as shown in FIG. 3A, when the transport roller 11 is rotationally driven and rotated in the rotation direction r, the uppermost film F1 of the film F stacked on the tray T and the film F2 below the film F are brought together. It is sent out and conveyed to the friction member 14 in the conveyance direction H at a conveyance speed of 20 mm / second or less.
[0033]
Then, as shown in FIG. 3B, when the two films F1, F2 pass through the intermediate roller 12 while being sandwiched between the friction member 14 and the intermediate roller 12 in the first inclined region 15, the films F1, The front ends Fa and Fb of F2 are in contact with the friction member 14 in the second inclined region 16.
[0034]
Since the second inclined region 16 where the tips Fa and Fb of the films F1 and F2 come into contact has a larger inclination angle θ2 and is abruptly inclined, as shown in FIG. 3C, the films F1 and F2 are Fa and Fb restrict the conveyance in the conveyance direction H by the frictional force between the friction member 14 and elastically deform and bend. Then, the front end Fa of the upper film F1 is first separated from the friction member 14, and the front end Fb of the lower film F2 is still in contact with the friction member 14, whereby the film F1 is separated from the film F2.
[0035]
Since the film F1 receives the conveying force of the conveying roller 11, it is further conveyed in the conveying direction H. Further, the film F2 is returned in the direction opposite to the conveying direction H by the return roller 13 that rotates in the reverse direction r ′. The return roller 13 may always be reversely rotated, or may be reversely rotated at a timing.
[0036]
1 to 3, the film is fed from the tray T while receiving the transport force S <b> 2 by the transport roller 11, and has an appropriate friction force while being biased against the friction member 14 by the intermediate roller 12. Because it receives, it is transported stably.
[0037]
Further, as described above, when the plurality of films F1 and F2 that have received the conveyance force from the conveyance roller 11 pass through the intermediate roller 12, the leading edges Fa and Fb are the second inclination with the large inclination of the friction member 14. It comes into contact with the region 16 and bends and can be separated. Therefore, since it can isolate | separate even if it does not use the reverse rotation roller with a torque limiter like the past, the damage to a film can be prevented.
[0038]
Next, the stable conveyance of the film and the prevention of scratches on the film in the present embodiment will be further described. As described above, when a plurality of laminated photosensitive films are kept in a degassed state and packaged in a barrier bag, the adhesion between the films proceeds, the film adhesion increases, and the films are one by one. Although the force required for separation becomes large, according to the experiments and examinations of the present inventors, the film adhesion force that the films as described above are in close contact with each other includes various film sizes, storage periods, and the like. Taking into account the conditions, it was found that the maximum was about 700 gf.
[0039]
Therefore, in the present embodiment, the film conveying force S2 by the conveying roller 11 is set to 1 kgf or more, which is larger than the film adhesion force, and the contact separation force S3 due to the contact on the friction member 14 is set to the film as shown in the following equation. By setting it to 800 gf or more, which is larger than the adhesion force, film conveyance and film separation can be performed reliably and stably. For this reason, the film transport mechanism according to this embodiment is particularly effective and stable when transporting a laminated film stored in a deaeration barrier bag in which strong adhesion due to a vacuum state easily occurs between the films. Film separation and conveyance can be performed.
[0040]
Film transport force S2> Contact separation force S3> Film adhesion force
On the other hand, according to further experiments and studies by the present inventors, FIG. 4 shows the relationship between the pressing force of the roller against the film and the film conveyance speed with respect to the presence or absence of a visible level of scratches on the film. From FIG. 4, if the film conveyance speed is 20 mm / second or less, the pressing force by the roller is 75 gf / cm ² or less, the film conveyance speed is 10 mm / second or less, and the pressing force by the roller is 100 gf / cm ² or less, the film is damaged. It turns out that does not occur.
[0042]
According to the conventional film transport mechanism as shown in FIG. 5, a nip force (pressing force) of 100 gf / cm ² or more is required when the film is separated and transported by the reverse rotation by the nip roller 93 with a torque limiter. As can be seen, this is insufficient to prevent the occurrence of scratches of a visible level. In the present embodiment, the pressing force S1 on the film by the conveying roller 11 is 75 gf / mm ² or less. Visible level can be reliably prevented from being scratched. This is presumably because scratches on the emulsion surface caused by the matting agent on the film surface side moving so as to rub the emulsion surface on the back surface do not occur because the pressing force to the film by the conveying roller 11 is small. .
[0043]
As described above, according to the film transport mechanism according to the present embodiment, the coefficient of dynamic friction with respect to the film is increased even if the pressing force to the film by the transport roller 11 is relatively small, so that a stable transport force can be obtained. In addition, since the film is urged by the intermediate roller 12 to the friction member 14, the film is stably conveyed under a relatively large frictional force. Even when the two films pass through the intermediate roller 12, the leading edge of the film abuts against the friction member 14 at a relatively steep second inclined region 15 and receives a relatively large frictional force, so that the movement is limited. Then, the film is separated by bending. In this way, stable film conveyance and separation are possible while preventing damage to the film.
[0044]
The conveyance mechanism 10 as described above is, for example, a laser imager that forms a visible image on a film by laser exposure and development on a photothermographic material film or a liquid development photosensitive film, paper, various sheet materials, and the like. The present invention can be applied to various known image forming apparatuses such as a copying machine, a laser printer, and an ink jet printer that form an image on a recording medium.
[0045]
In these image forming apparatuses, by providing the conveyance mechanism 10 in the storage / supply portion of the recording medium such as paper or film, the recording medium can be reliably and stably conveyed, so that the image formation can be performed stably. Moreover, even if the recording medium is easily scratched, it can be transported from the storage / supply part while preventing the scratch from occurring, so that the image quality formed on the recording medium can be maintained.
[0046]
Further, the film transport mechanism using the transport roller, the intermediate roller, and the inclined friction member as shown in FIGS. 1 to 3 can be configured compactly and is low in cost, and is preferable when applied to an image forming apparatus. This can contribute to downsizing and cost reduction of the apparatus.
[0047]
As described above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made within the scope of the technical idea of the present invention. For example, the transported body may be a heat-sensitive film, paper, an OHP film, various sheet materials other than paper, in addition to a photosensitive film such as a heat-developable photosensitive material and a liquid-developable photosensitive material used for medical image recording. Of course, it may be.
[0048]
Further, although the friction member 14 is inclined in two stages, the friction member 14 may be sequentially inclined in three stages or more. Further, the friction member 14 can be formed on the guide member 17 by adjusting the surface roughness so as to obtain a predetermined dynamic friction coefficient with an appropriate thickness using, for example, an elastomer-based thermoplastic resin.
[0049]
Further, as indicated by a broken line in FIG. 3A, a transport roller 11 ′ may be additionally provided, whereby a more sufficient film transport force S2 can be obtained. The conveyance roller 11 ′ may be configured in the same manner as the conveyance roller 11, and is preferably driven to rotate while synchronizing both.
[0050]
Further, as shown in FIG. 6, a reflective optical sensor 21 having a light emitting part and a light receiving part is arranged so as to detect the number of films between the intermediate roller 12 and the return roller 13. When the optical sensor 21 detects that there are a plurality of films, the return roller 13 rotates reversely to return the excess film F2. Further, the conveying roller 11 may be configured to be reversely rotated, and may be reversely rotated in synchronization with the return roller 13. Note that the optical sensor 21 can be configured to detect three types of no film, one sheet, and two sheets based on a signal from the light receiving unit. Also, the time from the start of film transport by the transport roller 11 is measured by a timer, and when the film cannot be detected by the optical sensor 21 even after a predetermined time has passed, a plurality of sheets are transported and cannot pass through the intermediate roller 12. It may be configured so that the conveying roller 11 is rotated in the reverse direction.
[0051]
【The invention's effect】
According to the present invention, it is possible to provide a transport mechanism and an image forming apparatus that can prevent the transported body from being damaged and can transport it stably when the stacked sheet-shaped transported bodies are separated and transported.
[Brief description of the drawings]
FIG. 1 is a side view schematically showing a film transport mechanism according to the present embodiment.
2 is a side view showing the friction member of FIG. 1. FIG.
FIG. 3 is a side view showing film transport and separation operations by the film transport mechanism of FIG. 1;
FIG. 4 is a diagram showing a relationship between a pressing force of a roller against a film and a film conveyance speed with respect to whether or not a visible level of scratches is generated in the film.
FIG. 5 is a side view schematically showing a conventional roller type film transport mechanism.
6 is a side view showing a modification in which an optical sensor is arranged for detecting the number of films on the downstream side of the intermediate roller of the film transport mechanism of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Film conveyance mechanism 11 Conveyance roller 12 Intermediate | middle roller 13 Return roller 14 Friction member 15 1st inclination area | region 16 2nd inclination area | region 21 Photosensor F Laminated | stacked film F1 Topmost film Fa Film F1 tip F2 Film F1 Lower film Fb Tip of film F2

Claims (13)

A conveying roller that is pressed against the sheet-shaped object to be conveyed and is driven to rotate and rotates to convey the object to be conveyed;
A friction member in contact with the fed transported body;
An intermediate roller that can be driven and rotated so as to be sandwiched between the friction member while urging the transported body,
The transport mechanism, wherein the transported body that has passed through the intermediate roller is inclined in the transport direction of the transported body so that the transported body contacts and bends at the tip. The transport mechanism according to claim 1, wherein the friction member is inclined in at least two stages, and a region where the tip abuts is larger than a region where the intermediate roller is disposed. The intermediate roller is disposed immediately before a region where the leading ends abut so that the plurality of transported members are separated at the tip when the plurality of transported members pass through the intermediate roller. The transport mechanism according to claim 1 or 2, characterized in that 4. The transport mechanism according to claim 1, further comprising a return roller that reversely rotates to return the transported body when a plurality of the transported bodies pass through the intermediate roller. 5. The gap between the intermediate roller and the friction member is controlled to be a constant amount so as to limit the number of sheets to be transported by the intermediate roller. 2. A transport mechanism according to item 1. The transport mechanism according to claim 1, wherein the transport target is sent out by the transport roller in a state where a plurality of transported bodies are stacked. 7. The transport mechanism according to claim 1, wherein a transport force of the transport roller with respect to the transported body is greater than a separating force with respect to the transported body in a region where the leading end abuts. . The transport roller is made of an elastic material that is pressed against the transported body with a pressing force of 75 gf / mm ² or less, has a rubber hardness of 20 ° or more, and has a dynamic friction coefficient of 2 or more with respect to the transported body. The transport mechanism according to any one of claims 1 to 7, wherein the transport mechanism is configured as described above. 2. The friction member is made of an elastic material that is inclined by 23 ° or more with respect to a horizontal direction in a region where the tip contacts, and has a dynamic friction coefficient of 2 or more with respect to the transported body. The conveyance mechanism of any one of thru | or 8. The transport mechanism according to claim 1, wherein the transport target is transported by the transport roller at a transport speed of 20 mm / second or less. 2. A sensor for detecting the number of conveyed objects is disposed downstream of the intermediate roller, and when the excessive number of sheets is conveyed, the excess conveying object is returned by the return roller. The transport mechanism according to any one of 1 to 10. The transport according to claim 10, further comprising a mechanism for returning the transported body when the transported body cannot be detected by the sensor within a predetermined time from the start of the transported body by the transport roller. mechanism. A transport mechanism according to any one of claims 1 to 12, comprising:
An image forming apparatus for forming an image on the transported transported body.

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