JP2007131448A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device A capable of winding out a paper P from a tip side while scanning and exposing it to light to store it temporarily and preventing improper development due to adhesion of dust to the paper P. <P>SOLUTION: A storage space part S for storing the paper P temporarily is provided on the downstream side of a light exposure engine 7 for scanning and exposing the paper P to light on the paper P. A winding mechanism 8 for the paper P is arranged in the storage space part S. Even when scanning and exposure to light are performed in a part of paper P, its tip side is wound around a winding drum 20 while it has slack. When amount of slack of the paper P downward below the winding drum 20 exceeds predetermined amount, the winding drum 20 is speedily rotated in accordance with a signal from a slack detection sensor 22 to wind out the slack so that a lower end part of the paper P is not brought into contact with a bottom face of the device A. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that forms an image (latent image) by carrying out scanning exposure on an image forming surface while conveying an image forming medium.

  2. Description of the Related Art Conventionally, as this type of image forming apparatus, an apparatus in which image exposure is performed on paper (e.g., corresponding to an image forming medium such as photographic paper) with a laser beam is known. A configuration example of such an apparatus is shown in FIG. This apparatus reads image data of frame images formed on a developed negative film and image data stored in various storage media, and prints and exposes an image on the emulsion surface of paper based on these image data. It is configured as follows.

  In FIG. 13, the paper magazine 100 stores the paper P in a rolled state. The paper P drawn out from the paper magazine 100 is transported along the transport path, and is cut into a predetermined print size by the paper cutter 101. The cut paper P is transported toward the image forming unit 103 by the transport unit 102. The image forming unit 103 feeds and scans laser light in the main scanning direction (a direction perpendicular to the sub-scanning direction, which is the transport direction) while transporting the paper P at a predetermined speed while the paper P is sandwiched between the transport rollers 104 for exposure. By doing so, an image (latent image) is exposed and formed on the surface of the paper P. The exposure transport roller 104 has two units arranged along the transport direction, and a scanning position by a laser beam is set between the upstream transport roller 104 and the downstream transport roller 104. The paper P on which the image has been printed and exposed is then transferred to other transport units 105 and 106 disposed on the downstream side of the image forming unit 103 and sent to the development processing unit.

  By the way, when scanning exposure is performed with laser light as described above, it is known that if the vibration or load fluctuation occurs on the paper P during exposure, exposure unevenness or the like occurs, which adversely affects the image quality of the printed image. Yes. Therefore, when the paper P is sent from the image forming unit 103 to the downstream side, a device is required so that vibration and load fluctuations are not applied by a conveyance system or the like arranged on the downstream side.

  In this regard, for example, in the image recording apparatus described in Patent Document 1, a so-called post-exposure buffer is provided by making the conveyance path on the downstream side of the image forming unit longer than a predetermined length. Thereby, it is possible to perform exposure in a stable load state so that vibrations and loads of the downstream transport system or the like do not act on the paper (photosensitive material) during scanning exposure.

  In the case shown in FIG. 13, until the scanning exposure in the image forming unit 103 is completed, the paper P is fed into the accommodation space 107 provided on the downstream side, and the leading end side of the paper P is shown by a one-dot chain line in the drawing. As you can see, it hangs down naturally. By doing so, the post-exposure buffer can be enlarged without lengthening the transport path too much.

Furthermore, the inventors of the present application arrange a take-up drum in the accommodation space 107 downstream of the image forming unit 103, and with this drum, the paper P during scanning exposure is taken up from the leading end side, and temporarily An image forming apparatus designed to be stored has been developed and a patent application has been filed (for example, Japanese Patent Application No. 2005-179582). In this case, by winding the paper P, the capacity of the post-exposure buffer can be sufficiently increased without enlarging the accommodation space 107.
JP-A-10-325983

  By the way, when the paper during scanning exposure is wound up in the image forming unit as in the previous application, image formation is performed so that the load fluctuation applied to the paper due to the winding does not cause uneven exposure. It is desirable to wind up the paper carried out from the section in a state where the paper is slack.

  However, when the paper is wound in such a slack state, the lower end of the paper that hangs downward from the take-up drum when the slack increases, comes into contact with the bottom surface of the device facing the storage space. As a result, there is a possibility that dust accumulated there adheres to the image forming surface of the paper P and causes development failure.

  In particular, when the paper is cut to a predetermined length in the apparatus, the paper powder generated at the time of cutting is scattered in the apparatus and collected on the bottom surface of the apparatus. It is inevitable that it will occur.

  Furthermore, if the slack of the paper is large, it may spread outward from the take-up drum and come into contact with the wall surface of the device facing the accommodation space.

  The present invention has been made in view of the above points, and an object of the present invention is to form an image forming apparatus that winds and temporarily stores paper (image forming medium) during scanning exposure as described above. Is to prevent development failure due to adhesion of dust to the image forming medium.

  In order to achieve the above object, the present invention is provided with means for preventing dust from adhering to an image forming medium carried out from the image forming unit.

  Specifically, according to the first aspect of the present invention, after the image forming medium wound in a roll shape is cut into a predetermined length, scanning exposure is performed in the image forming unit while conveying the image forming medium, and then development processing is performed. The image forming apparatus is intended to be conveyed to a part. When the upper limit value of the conveyance direction length of the image forming medium that can be processed in the image forming unit is equal to or greater than the conveyance distance from the image forming unit to the development processing unit, the image carried out from the image forming unit A winding storage unit that winds up and temporarily stores the forming medium, and an adhesion suppression unit that suppresses the adhesion of dust to the image forming medium wound up in the winding storage unit.

  With the above configuration, when an image is formed, scanning exposure is performed in the image forming unit while conveying the image forming medium cut to a predetermined length. At this time, an image longer than a certain length in the conveying direction is used. The forming medium is unloaded from the image forming unit in a state where scanning exposure is performed on a part of the rear side in the transport direction.

  Even when the conveyance direction length of the image forming medium thus carried out is longer than the conveyance distance from the image forming unit to the development processing unit, the leading end side of the image forming medium is temporarily taken up by the take-up storage unit. In other words, when the take-up storage unit functions as a post-exposure buffer, the leading edge of the image forming medium does not reach the development processing unit, and vibrations and load fluctuations associated with the development processing and the like occur. It is not transmitted to the exposed portion of the image forming medium and causes uneven exposure.

  In addition, since the image forming medium is not simply sent into the space but is wound up, the capacity of the post-exposure buffer should be sufficiently increased without increasing the space for storing the image forming medium. Can do. Thereby, the enlargement of the apparatus can be suppressed while an image can be formed without causing uneven exposure on an image forming medium that is very long in the transport direction.

  Furthermore, since means (adhesion suppression means) for suppressing the adhesion of dust to the image forming medium wound up in the take-up storage unit is provided, the development failure due to the adhesion of the dust is prevented. Can be prevented.

  That is, when the image forming medium is wound in the winding storage section as described above, the load acting on the image forming medium accompanying the winding is unloaded from the image forming section so as not to cause uneven exposure. It is preferable that the image forming medium to be wound is wound with a slack. For this purpose, the take-up storage unit includes a take-up drum for taking up the image forming medium and an accommodating space for containing the take-up drum, and slack in the image forming medium carried out from the image forming unit as described above. For example, the image forming medium may be wound at an average lower speed than the carry-out speed.

  And even if the slack of the image forming medium wound up in this way increases and spreads outward from the take-up drum, it does not come into contact with the wall surface of the take-up storage unit and cause dust adhesion. In addition, for example, an adhesion suppressing means for adjusting the winding speed of the image forming medium may be provided (invention of claim 2).

  More specifically, the adhesion suppression means includes, for example, an optical sensor provided so as to detect an image forming medium that sags outside the winding drum in a state of being separated from the wall surface of the winding storage unit, and the sensor. And a take-up speed control means for increasing the take-up speed at the time of detecting the image forming medium in accordance with the signal (invention of claim 3).

  In this way, when the slack increases during winding and spreads to a certain extent beyond the outside of the drum, this is detected by the optical sensor, and the winding speed control means responds to the signal from this sensor. Increasing the rotation speed (winding speed) of the winding drum reduces the sag of the image forming medium. Therefore, it is possible to prevent the image forming medium from coming into contact with the wall surface of the take-up storage section while winding the image forming medium in a slack state.

  In addition, a preferable configuration of the optical sensor includes a light emitting element and a light receiving element which are arranged on the outer side of the winding drum so as to face each other in a direction intersecting the rotation axis direction, and both the elements are rotated with respect to each other. It is offset in the axial direction. In this case, the optical axis from the light emitting element to the light receiving element is not perpendicular to the rotation axis direction of the take-up drum (that is, the width direction of the image forming medium) and is inclined, so that the width of the image forming medium is considerably narrow. However, the possibility that this will block the optical axis is sufficiently high, and the detection accuracy is improved.

  In addition to the preferable configuration as described above, as the adhesion suppressing means, the lower end portion of the image forming medium that hangs outward from the take-up drum is separated from the bottom surface of the take-up storage portion facing the storage space portion. A thread-like holding member constructed so as to be held can also be used (invention of claim 4). In this way, dust can be prevented from adhering to the image forming medium by a simple configuration in which the lower end portion of the slack of the image forming medium is held by the thread-like holding member that is difficult to adhere dust. .

  As described above, according to the image forming apparatus of the present invention, since the image forming medium carried out from the image forming unit is wound up, it is possible to prevent occurrence of uneven exposure even in an image forming medium that is very long in the transport direction. While providing a post-exposure buffer, it is not necessary to make the space for that purpose too large, and the enlargement of the apparatus can be sufficiently suppressed.

  In addition, since the image forming medium unloaded from the image forming unit is wound in a slack state, even if a load fluctuation is applied to the paper as a result of the winding, this causes uneven exposure. It will not cause.

Further, the winding speed of the image forming medium is adjusted so that the image forming medium wound in the slack state does not contact the wall surface of the winding storage section, or the lower end of the image forming medium is thread-shaped holding member. Or the like, it is possible to suppress the adhesion of dust to the image forming medium and to prevent development failure.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature and is not intended to limit the present invention, its application, or its use.

(Overall configuration of photo processing system)
FIG. 1 shows a configuration of a photographic processing system provided with an image forming apparatus A according to an embodiment of the present invention. This photographic processing system has a function of acquiring image data, printing an image on an emulsion surface (corresponding to an image forming surface) of paper (corresponding to an image forming medium) based on the image data, and creating a photographic print. I have. This photographic processing system also scans frame images formed on developed photographic film and obtains film data (not shown), storage media for digital cameras, and other recording media. A media reading unit (not shown) for reading image data stored in the medium is provided.

  The paper magazines 3 and 3 shown in FIG. 1 respectively accommodate rolls of long paper wound in a roll shape, and the paper magazines 3 and 3 can be attached to and detached from the main body of the image forming apparatus A. Is attached. Of the two paper magazines 3 and 3 attached to the main body of the image forming apparatus A, one paper magazine 3 is selected according to the print size and the like, and is drawn out from the selected paper magazine 3. The paper P is transported along a predetermined transport path. That is, the direction of the paper drawn out from the paper magazine 3 is changed by the advance roller unit 4 and cut into a predetermined print size by the paper cutter 5. Then, the cut paper P is transported by the transport unit 6 to an exposure engine 7 (corresponding to an image forming unit) located on the downstream side.

  The exposure engine 7 is provided with an upstream exposure transport roller 9a and a downstream exposure transport roller 9b. Between these exposure transport rollers 9a and 9b, an exposure position for exposing the paper P with laser light is set. A paper detection sensor 10 is provided on the upstream side of the exposure conveyance roller 9, and when the paper P is fed in, the front end (front end in the conveyance direction) portion is detected and a signal is output. . The paper detection sensor 10 includes a light emitting element that outputs infrared light and a light receiving element that receives the light. By detecting the position of the paper P by the paper detection sensor 10, the exposure start timing at the exposure position can be determined.

  The exposure engine 7 has a known structure and optically modulates laser light output from a laser light source (laser diode or the like) based on image data and irradiates the paper P with the light-modulated laser light. Then, the image is exposed. That is, the paper P is transported at a predetermined speed (constant speed) while being sandwiched between the exposure transport rollers 9a and 9b, while the laser beam is orthogonal to the transport direction (sub-scanning direction) of the paper P. Since scanning is performed in the scanning direction, an image (latent image) is printed and exposed on the paper P line by line.

  Then, while the scanning exposure as described above is performed, the paper P is sent out downstream from the exposure position by the downstream exposure transport roller 9b. The first and second transport units 11 and 12 are provided on the downstream side of the exposure engine 7. As will be described in detail later, the first transport unit 11 is provided to be rotatable around a predetermined rotation axis. And has a function of delivering the paper P delivered by the downstream exposure conveyance roller 9 b to the second conveyance unit 12. Then, the second transport unit 12 sends the paper P received from the first transport unit 11 to a development processing unit (not shown).

  Further, in order to temporarily store (store) the paper P having a length in the transport direction of a predetermined length or more (for example, 594.1 mm or more) on the downstream side of the exposure engine 7 (left side of the exposure engine 7 in FIG. 1). Storage space S is provided. That is, when the paper P is longer than the distance from the exposure position of the exposure engine 7 to the development processing unit, the leading end of the paper P enters the development processing unit in a state where scanning exposure is performed in a part thereof, The vibrations and load fluctuations that occur along with this may be transmitted to the exposed portion of the paper P and cause uneven exposure. In this embodiment, however, the exposure transport roller 9b prevents such load fluctuations from occurring. The paper P sent out by is temporarily stored.

  In this embodiment, a take-up drum 20 for taking up the paper P is arranged in the accommodation space S. The take-up drum 20 is provided with a pressure roller 21 for pressing and pinching the front end portion of the paper P on the outer peripheral surface thereof. A mechanism 8 is configured. The accommodation space S and the take-up mechanism 8 constitute a take-up storage unit that takes up and temporarily stores the paper P carried out from the exposure engine 7.

  Further, below the winding drum 20, an optical sensor 22 for detecting the paper P sagging below is provided as will be described later. The sensor 22 is configured such that the light receiving element 22b receiving the light from the light emitting element 22a outputs a signal to a control system (sag amount detecting means 41 described later) of the image forming apparatus A, to the light receiving element 22b. When the incident light is blocked by the paper P, it is determined that the amount of sag of the paper P is larger than a predetermined amount. Hereinafter, the sensor 22 is referred to as a sag detection sensor 22.

(Constitution of accommodation space)
Next, the structure in the said accommodation space part S is demonstrated based on FIG. First, the first transport unit 11 is disposed further downstream of the downstream exposure transport roller 9b, and includes a sandwiching transport roller pair 11a and a guide plate 11b. The position in the height direction of the pair of nipping and conveying rollers 11a is set to be the same height position as that of the exposure and conveying roller 9, and an opening 11c is formed at the upstream end of the guide plate 11b. Therefore, the paper P can be easily received.

  Further, the first transport unit 11 is configured to be capable of rotating by 90 ° around a predetermined rotation axis (see FIG. 12), and when it is rotated by 90 °, the paper P is delivered to the second transport unit 12. be able to. The second transport unit 12 includes a plurality of nipping and transporting roller pairs 12a that are arranged along the transport path and driven by a driving mechanism (not shown), and a guide plate 12b that guides the paper P. The first transport unit 11 serves to feed the paper P received from 11 to the development processing unit.

  The take-up drum 20 is configured to be rotatable around the rotation axis 20a. Before the winding of the paper P by the winding drum 20 is started, the outer peripheral surface of the winding drum 20 and the surface of the pressure roller 21 are separated from each other and a gap is formed. Thereby, the leading end of the conveyed paper P is easily inserted into the gap between the winding drum 20 and the pressure roller 21.

  The receiving height of the paper P by the winding drum 20 is set to be the same as the height of the conveyance surface by the exposure conveyance roller 9 and the conveyance surface before the rotation of the first conveyance unit 11. Yes. Thereby, the paper P sent out by the exposure transport roller 9 can be smoothly received on the winding drum 20 side. In the state shown in FIG. 2, the shaft core of the pressure roller 21 is located just above the shaft core of the winding drum 20.

  Further, a winding movement mechanism 13 for moving the winding drum 20 in the vertical direction is provided in the accommodation space S, and a winding mechanism including a pressure roller 21 in the winding drum 20. 8 is moved up and down between an upper first position (position in FIG. 2) close to the exposure position of the exposure engine 7 and a lower second position (position in FIG. 9) far from the exposure position. It has become.

  That is, the winding movement mechanism 13 includes a guide member 13a extending in the vertical direction and a timing belt 13b for moving the winding mechanism 8 along the guide member 13a. A support 15 for supporting the take-up mechanism 8 is fixed, and the take-up mechanism 8 can be moved up and down by driving the timing belt 13b by a motor (not shown). The support 15 is mounted with drum driving means (motor, speed reduction mechanism, etc.) for rotationally driving the take-up drum 20.

  Here, the storage space S is adjacent to the development processing unit and is partitioned by the wall surface 14, but when the paper P is moved up and down in the state where the paper P is wound around the winding drum 20, the paper P It is preferable not to rub the wall surface 14. On the other hand, if the accommodating space S is made larger, rubbing between the wall surface 14 and the paper P can be eliminated, but there is a problem that the entire apparatus becomes larger.

  Therefore, the take-up moving mechanism 13 is configured such that the take-up mechanism 8 moves obliquely downward as shown in FIG. Specifically, the winding movement mechanism 13 is configured to move in a direction away from the wall surface 14 as the winding mechanism 8 is lowered, so that the paper P does not rub the wall surface 14. The winding mechanism 8 can be moved downward in the accommodation space S.

  As will be described in detail below, when the paper P is wound around the winding drum 20 of the winding mechanism 8 or when the entire winding mechanism 8 is moved downward by the winding moving mechanism 13, basically, The paper P is slackened. By doing this, even if the leading end side is wound up or moved downward in the state where the image is formed on a part of the paper P as described above, the exposure position has a large vibration. And load fluctuations are not transmitted, and the occurrence of uneven exposure can be prevented.

-Winding mechanism-
Below, the detailed structure of the winding drum 20 and the press roller 21 which comprise the winding mechanism 8 is demonstrated based on FIG. FIG. 4 shows a cam mechanism (corresponding to roller interval changing means) for moving the pressure roller 21 in the pressure direction.

  The take-up drum 20 is configured to be rotatable around a fixed shaft 200. The take-up drum 20 is made of resin, and takes up paper P on its outer peripheral surface. At both ends in the axial direction of the take-up drum 20, circumferential grooves 202 for engaging the coil spring 24 for urging the press roller 21 in the press-bonding direction are provided. A connecting gear 201 for rotating the take-up drum 20 is provided on the end side of the circumferential groove 202 at one end.

  The pressure roller 21 includes a roller support shaft 210 disposed substantially parallel to the axis of the take-up drum 20, and a plurality of resin rollers provided in a line in the axial direction so as to cover the outer peripheral surface of the roller support shaft 210. Are provided with support shafts 211, 211,... And crimping members 212, 212,. The crimping member 212 is formed of a foaming member having elasticity like sponge (for example, urethane foam), and is easily elastically deformed when the leading end of the paper P is sandwiched between the outer peripheral surface of the winding drum 20. By doing so, the load fluctuation to this paper P is relieved.

  The roller support shaft 210 is fitted with an E-ring 213 for preventing the support shafts 211, 211,... From moving in the axial direction with respect to the roller support shaft 210. Further, grooves 214 and 214 for engaging the coil spring 24 are formed at both ends in the axial direction. Further, cam connecting shafts 215 and 215 are respectively provided at both axial ends of the roller support shaft 210 and inside the groove portions 214 and 214 in the axial direction, and the cam connecting shafts 215 are cam mechanisms which will be described later. By moving up and down according to the shape of the cam surface 203a, the pressure roller 21 can be moved in the pressure bonding direction or the non-pressure bonding direction.

  With such a configuration of the winding mechanism 8, when the winding drum 20 rotates, the pressure roller 21 also rotates and moves along the outer peripheral direction of the winding drum 20 (rotates around the fixed shaft 200) in conjunction with the rotation. become. The pressure roller 21 itself is rotatably inserted into the roller support shaft 210 so that it can rotate freely.

  Next, a cam mechanism for moving the pressure roller 21 in the pressure bonding direction will be described with reference to FIG. FIG. 4 shows a cross-sectional view of the winding mechanism 8 shown in FIG. 3 cut along a plane perpendicular to the fixed shaft 200 at a portion where a cam is formed. As shown, the cam member 203 is coupled to the fixed shaft 200 via the clutch member 204. The cam member 203 has a cam surface 203a, and the tip 215a of the cam coupling shaft 215 is always in contact with the cam surface 203a by the biasing force of the coil spring 24 described above.

  Since the cam surface 203a is formed in a range of θ = 210 ° on the outer peripheral surface of the cam member 203, a range in which the cam connecting shaft 215 (the pressure roller 21) can be rotationally moved with respect to the cam member 203 is also 210 °. It becomes. A first wall surface 203b and a second wall surface 203c are formed at both circumferential ends of the cam surface 203a. When the cam connecting shaft 215 moves relative to the cam surface 203a, the cam connecting shaft 215 Are positioned in contact with the wall surfaces 203b and 203c.

  4A is a diagram showing an initial state in which a gap is formed between the pressure roller 21 and the take-up drum 20, and FIG. 4B shows a state where the pressure roller 21 rotates 210 ° and the pressure roller 21 is rotated. It is a figure which shows the state by which the paper P was crimped | bonded by. Thus, when the take-up drum 20 is rotated by 210 °, the state shown in FIG. 4B is obtained, but when the take-up drum 20 is further rotated, the cam connecting shaft 215 comes into contact with the second wall surface 203c, The cam member 203 is forcibly rotated around the fixed shaft 200 together. At this time, the clutch member 204 slips. That is, by providing the clutch member 204, the pressure roller 21 can be rotated beyond a range (210 °) regulated by the cam member 203.

-Sag detection sensor-
Next, the slack detection sensor 22 provided below the winding drum 20 will be described. As shown in FIG. 2, the light emitting element 22a and the light receiving element 22b of the sag detection sensor 22 are opposed to each other in a direction crossing the direction of the rotation axis (a direction perpendicular to the drawing sheet) below the take-up drum 20. In addition, the optical axis line connecting the two is offset up and down so as to be inclined with respect to the horizontal line, and is also offset in the rotational axis direction of the winding drum 20.

  Thus, since the light emitting element 22a and the light receiving element 22b are arranged offset in the direction of the rotation axis of the take-up drum 20, the line of the optical axis connecting them is orthogonal to the rotation axis of the take-up drum 20. When viewed in the vertical direction, not in the plane (for example, in the drawing), the line of the optical axis is not perpendicular to the direction of the rotation axis (that is, the width direction of the paper P) but is slanted. . For this reason, even when the paper P having a considerably narrow width is used, and even if it is twisted, the possibility that the paper P will block the optical axis becomes sufficiently high, and the detection accuracy is improved.

(Control block diagram)
Next, the control block configuration of the image forming apparatus A will be described with reference to FIG. In FIG. 5, the paper leading edge detection means 30 detects the leading edge of the paper P based on the output signal from the paper detection sensor 10 and determines that the paper P has arrived. In addition, it is possible to recognize at which position the paper P is present on the downstream side based on the timing at which the leading edge of the paper P is detected. The roller driving unit 31 includes a driving mechanism and a driving circuit for driving the exposure conveyance roller 9. Further, the transport amount detection means 32 is configured to detect the transport amount of the paper P by detecting the rotation amount of the exposure transport roller 9 with an encoder or the like.

  The paper position detection unit 33 is configured to detect various positions of the paper P based on the front end position of the paper P detected by the paper front end detection unit 30 and the transport amount of the paper P detected by the transport amount detection unit 32. It has the function which calculates | requires and calculates | requires. Specifically, the paper position detection unit 33 includes an exposure start timing detection unit 33a, a paper rear end escape detection unit 33b, and an insertion detection unit 33c.

  The exposure start timing detection means 33a is configured to detect the exposure start timing by the laser beam based on the leading edge position of the paper P detected by the paper leading edge detection means 30. That is, since the position of the paper detection sensor 10 and the exposure position by the laser beam are determined by design, if the leading end position of the paper P is known, the exposure start timing detection means 33a calculates the exposure start timing at the exposure position. Can do.

  The paper rear end escape detecting means 33b is for detecting that the rear end of the paper P on which image printing exposure has been completed has escaped from the printing exposure position. Further, the insertion detecting means 33c is for detecting that the leading end of the paper P has been inserted into the gap between the winding drum 20 and the pressure roller 21. The amount of insertion into this gap can be set as appropriate, but is usually about 20 mm.

  The exposure control unit 34 is configured to start scanning exposure of an image with laser light based on the calculation result of the exposure timing by the exposure start timing detection unit 33a. Thus, the latent image can be formed by scanning the emulsion surface of the paper P conveyed at a predetermined speed with the laser light light-modulated by the image data.

  The first transport unit driving unit 35 has a mechanism for driving the first transport unit 11. Specifically, the first transport unit driving unit 35 rotates the entire first transport unit 11 by 90 ° with the crimp driving means 35a for switching the transport roller pair 11a between the crimping state and the non-crimping state. Unit rotation means 35b for switching between the horizontal state and the vertical state, and roller drive means 35c for rotationally driving the conveyance roller pair 11a are provided. Here, when the image is exposed by the exposure engine 7, the press driving means 35 a puts the transport roller pair 11 a into a non-pressing state so that no load is applied to the paper P.

  The second transport unit driving unit 36 has a mechanism for driving the second transport unit 12, and includes a roller driving unit 36a that rotationally drives the transport roller pair 12a. Then, the transport unit drive control unit 37 performs drive control of the first transport unit 11 and the second transport unit 12. For example, when the paper position detection unit 33 detects that the rear end of the paper P has escaped from the printing exposure position, the transport roller pair 11a is switched to the press-bonded state.

  In the print size setting means 40, data of the print size of the paper P on which the image is exposed is set and stored. Then, based on the print size data stored in the print size setting means 40, the winding movement mechanism 13 and the winding drum 20 are controlled. For example, when the length of the paper P is shorter than a predetermined length (430.1 mm in the present embodiment), the winding of the paper P by the winding mechanism 8 is not performed.

  Based on the output signal from the sag detection sensor 22, the sag amount detection means 41 has a sag amount equal to or greater than a predetermined amount (that is, the lower end portion of the paper P that sags below the winding drum 20 faces the accommodation space portion S. Whether or not it has come down to a predetermined height from the bottom surface of the device A). The drum driving unit 42 includes a mechanism for driving the winding drum 20 to rotate. The rotation amount detection means 43 is configured to detect the rotation amount of the winding drum 20. For example, the amount of rotation can be monitored by an encoder that rotates in conjunction with the winding drum 20.

  The drum rotation control means 44 has a function of performing rotation drive control of the winding drum 20. That is, the drum rotation control means 44 detects the leading end insertion of the paper P by the insertion detection means 33c, the print size data stored and set in the print size setting means 40, and the signal from the sag detection sensor 22. Based on the above, rotation and stop control of the winding drum 20 is performed as will be described in detail with reference to the flowchart below.

  The winding control means 45 performs drive control of the winding moving mechanism 13 according to the length of the paper P in the transport direction. For example, in the case of the paper P having a short length, since the winding operation by the winding mechanism 8 is not performed, the winding drum 20 is allowed to escape to the lowest second position. For the other papers P, when the rotation amount detecting means 43 detects that the pressure bonding operation by the pressure roller 21 is completed (θ = 210 ° rotation), the winding drum 20 is moved from the first position to the second position. To control. However, in the case of the paper P having a relatively short length (that is, an intermediate length), the paper P is crimped by the winding mechanism 8, but the slack detection sensor 22 detects the amount of slack. Since this is not performed, the winding drum 20 is moved to an intermediate position (third position) between the first position and the second position. Information regarding the length dimension of the paper P can be obtained from the print size setting means 40.

  The control block shown in FIG. 5 can be constructed by the function of computer software or hardware. Which function is realized by software and which function is realized by hardware can be appropriately determined according to the paper processing capability and the like.

(Conveying operation after exposure)
Next, the conveying operation for sending the paper P on which the image is exposed by the exposure engine 7 to the development processing unit will be described with reference to the flowcharts of FIGS. 6A and 6B and FIGS. 2 and 7 to 12. It is assumed that the print size setting means 40 is set with a print size having a length that requires the winding mechanism 8 to be lowered to the second position.

  First, the leading edge of the paper P cut to a predetermined print size is detected by the paper detection sensor 10 and the paper leading edge detection means 30 (step ST1). A predetermined timing elapses after the leading edge of the paper P is detected, and the exposure start timing detection means 33a detects that the exposure start timing is reached, and then the exposure control unit 34 applies laser to the emulsion surface of the paper P. The light is scanned and exposed to form an image (step ST2).

  While performing scanning exposure with laser light in this way, the paper P is transported toward the downstream side by the exposure transport roller 9, and the leading end of the paper P passes through the guide plate 11 b of the first transport unit 11. At this time, since the pair of transport rollers 11a of the first transport unit 11 is in a state where the pressure bonding is released, the paper P passes through the position of the first transport unit 11 without applying a large load to the paper P. Can do.

  Since the take-up drum 20 is set in the first position as shown in FIG. 2 in advance, the paper P that has passed through the first transport unit 11 as described above is directly between the take-up drum 20 and the pressure roller 21. It is conveyed toward the gap between them. The leading end position of the paper P is calculated by the paper position detection unit 33 based on the detection result by the paper detection sensor 10 and the transport amount of the paper P. Based on the calculation result, the insertion detection unit 33c causes the paper P to be detected. It is determined whether or not the tip has been inserted into the gap between the winding drum 20 and the pressure roller 21 (step ST3).

  The insertion detection means 33c detects that the leading end of the paper P is inserted into the gap between the winding drum 20 and the pressure roller 21 based on the output signal from the paper detection sensor 10. However, the present invention is not limited to this, and a dedicated sensor for detecting the insertion of the paper P may be provided in the vicinity of the insertion position.

  If it is detected that the leading edge of the paper P is inserted into the gap between the winding drum 20 and the pressure roller 21 as described above (YES in step ST3), the winding drum 20 starts to rotate (step). ST4). FIG. 2 shows a state immediately after the leading end of the paper P is inserted into the gap. Then, the take-up drum 20 rotates counterclockwise in FIG. 2, and the pressure roller 21 similarly rotates around the rotation axis 20a. Thereafter, the gap between the pressure roller 21 and the take-up drum 20 is gradually narrowed by the cam mechanism described above, and the pressure roller 21 moves in the pressure direction.

  At this time, scanning exposure with a laser beam is performed on the rear side in the transport direction of the paper P. That is, the front end portion of the paper P that is being exposed in part is sandwiched between the winding drum 20 and the pressure roller 21, and the periphery of the winding drum 20 that sandwiches the front end portion of the paper P in this way. The speed is set to be substantially the same as or slightly slower than the feeding speed (unloading speed) of the paper P by the exposure transport roller 9, so that the paper P has a slight slack, The tip end side can be wound up without applying a large load fluctuation.

  Then, it is determined whether or not the winding drum 20 has rotated by a predetermined amount (210 ° in the example in the figure) (step ST5). When it is determined that the winding drum 20 has rotated by a predetermined amount (in the case of YES in step ST5), the winding is performed. The rotation of the take-up drum 20 is stopped (step ST6). The rotation amount is detected by the rotation amount detection means 43. FIG. 7 is a view showing a state immediately after the rotation of the winding drum 20 is stopped.

  After stopping the rotation of the winding drum 20 in the step ST6, the winding movement mechanism 13 is driven by the winding control means 45 to lower the winding mechanism 8 from the first position to the second position (step ST7). ). The control procedures in steps ST6 and ST7 may be performed substantially simultaneously. For example, the downward movement of the winding mechanism 8 may be started immediately before the winding drum 20 stops.

  The downward moving speed of the take-up mechanism 8 is also set so as to be slower than the speed at which the paper P is fed into the accommodating space S, thereby allowing the paper P to be slack. Thus, the winding mechanism 8 can be moved downward without adding a large load fluctuation thereto. FIG. 8 shows a state in which the take-up drum 20 has moved to an intermediate position (third position) between the first position and the second position, and the paper P between the take-up drum 20 and the first transport unit 11. Indicates that sagging has begun to occur in the part. FIG. 9 shows a state where the winding mechanism 8 has been lowered to the second position.

  Even after the rotation of the take-up drum 20 is stopped and moved to the second position as described above, the paper P is fed into the accommodation space S by the exposure transport roller 9. At this time, it is determined by the paper trailing edge escape detection means 33b whether or not the trailing edge of the paper P has reached the first transport unit 11 (step ST8). Note that the state in which the rear end of the paper P has reached the first transport unit 11 is a state in which the rear end of the paper P protrudes slightly upstream from the sandwiching transport roller pair 11a. Is determined on the basis of the detection result of the above and the transport amount of the paper P. However, a dedicated sensor for detecting the arrival of the trailing edge of the paper may be provided in the first transport unit 11.

  If it is determined that the rear end of the paper P has arrived (in the case of YES in step ST8), the process proceeds to step ST15 described later, whereas if it is determined in step ST8 that the rear end has not reached (NO) In step ST9, it is determined whether the amount of sag is equal to or greater than a predetermined amount. That is, even after the take-up mechanism 8 is moved to the second position as described above, the paper P is fed in, so that the sagging gradually increases, and eventually the light emitting element 22a as shown in FIG. The light from the light receiving element 22b to the light receiving element 22b is blocked by the lower end of the paper P that hangs below the winding drum 20.

  Then, based on the signal from the sag detection sensor 22, the sag amount detection means 41 determines that a sag of a predetermined amount or more has occurred (in the case of YES in step ST9), and the winding drum 20 is rotated again (step S9). ST10). Since the rotation of the take-up drum 20 is performed at a higher speed than the rotational drive in the previous step ST4, the paper P is taken up quickly, and the increased slack is eliminated at an early stage.

  In other words, even if a large sagging paper P hangs downward from the take-up drum 20, its lower end does not come into contact with the bottom surface of the apparatus, and dust such as cutting waste (paper dust) collected on the paper P is collected on the paper. It does not adhere to the emulsion surface of P. Even when the sag increases as described above, the emulsion surface of the paper P that sags on the side rubs against the wall surface 14 because the take-up drum 20 moves obliquely downward in the direction away from the wall surface 14. Nor.

  Then, when the blocking state of the light from the light emitting element 22a is resolved by the rotation of the winding drum 20, the sag amount detecting means 41 is based on the output of the light receiving element 22b, that is, the signal from the sag detecting sensor 22. Therefore, it is determined that the amount of sag is less than the predetermined amount (in the case of YES at step ST11), and the winding drum 20 is stopped again (step ST12). Thereafter, the process returns to step ST8, and it is determined whether or not the rear end of the paper P has reached the first transport unit 11.

  On the other hand, if the light blocking state of the light emitting element 22a is not resolved even by the rotation of the winding drum 20, it is determined in step ST11 that the amount of sag is not less than a predetermined amount (NO), and the process proceeds to step ST13 once. The same determination as in ST8 is performed. If the trailing edge of the paper has not reached the first transport unit 11 (NO in step ST13), the process returns to step ST11 and the amount of sag is monitored again. On the other hand, if the trailing edge of the paper has reached the first transport unit 11 (YES in step ST13), the rotation of the take-up drum 20 is stopped (step ST14). FIG. 11 shows a state in which the take-up drum 20 is further rotated from the state of FIG. 10, but since the pressure roller 21 is rotated by 210 ° or more, the clutch member 214 is slipping.

  Control of rotation and stop of the take-up drum 20 as described above is performed based on the function of the drum rotation control means 44. That is, the amount of sag of the paper P is detected by the sag detection sensor 22, and based on this, intermittent drive control is performed to repeatedly rotate and stop the take-up drum 20 (the number of repetitions of this rotation and stop is determined by the print size). ), It is possible to effectively prevent the dust from adhering to the paper P by preventing the lower end portion of the paper P that hangs below the take-up drum 20 from coming into contact with the bottom surface of the apparatus.

  In other words, the drum rotation control means 44 winds up the paper P intermittently (that is, at an average lower speed than the carry-out speed) so as to cause a sag in the paper P carried out from the exposure engine 7. At that time, the winding that resumes winding of the paper P according to the detection signal from the sag detection sensor 22 so that the lower end of the paper P that sags below the winding drum 20 does not contact the bottom surface of the apparatus. Taking speed control means.

  Thus, when the rear end of the paper P reaches the first transport unit 11 and the winding drum 20 stops rotating, the clamping transport roller pair 11a of the first transport unit 11 is non-crimped by the crimp driving means 35a. The state is switched to the crimping state (step ST15). Then, as shown in FIG. 12, the first transport unit 11 is rotated 90 ° by the unit rotating means 35b to assume a vertical posture (step ST16). At this time, the transport surface of the first transport unit 11 and the transport surface of the second transport unit 12 are in a line.

  Next, the conveyance roller pair 11a is rotationally driven to convey the paper P toward the second conveyance unit 12, and deliver it (step ST17). At this time, the take-up drum 20 is rotated in the reverse direction (clockwise). As a result, the paper P sandwiched by the second transport unit 12 is transported upward, sent to a development processing section (not shown), and subjected to development processing. That is, the front side and the rear side in the transport direction are switched between the time when the paper P is wound up by the winding mechanism 8 and the time when the paper P is transported by the second transport unit 12 thereafter.

  When the delivery of the paper P to the second transport unit 12 is completed as described above (step ST18), the paper P is reset to an initial state to accept the next paper P. That is, the take-up drum mechanism 8 is raised from the second position to the first position, and the pressure roller 21 is also returned to the initial position so that the next paper P can be received. Further, the first transport unit 11 is also returned to the horizontal state, and the transport roller pair 11a is brought into a non-pressing state.

  In the above description, the transport method in the case where the length of the paper P in the transport direction is a print size greater than or equal to a predetermined value (for example, 594.1 mm, the first length) has been described. When the value is equal to or less than the predetermined value, the following two operations are performed according to the length.

  That is, when the transport direction length of the paper P is shorter than a predetermined length as in the service size (for example, when the length is shorter than 430.1 mm, the second length), the paper P is wound up by the winding drum 20. Since there is no need, the winding mechanism 8 is moved from the beginning to the second position. As a result, the paper P on which the image has been exposed by the exposure engine 7 is immediately changed in direction by the first transport unit 11 and transferred to the second transport unit 12.

  On the other hand, when the length of the paper P is a third length intermediate between the first length and the second length (430.1 to 594.1 mm in the example of the present embodiment), the winding mechanism 8 Only the winding operation by, and the movement of the winding mechanism 8 to the intermediate position (third position) between the first position and the second position are performed. That is, in step ST7 of FIG. 6A, the winding drum 20 is lowered to the intermediate position. At this time, in the case of the paper P of the third length, since there is no need to detect sag by the sag detection sensor 22, sag detection is not performed. Therefore, in FIG. 6A and FIG. 6B, the operation | movement except the step regarding a sagging detection is performed.

  As described above, according to the image forming apparatus A according to this embodiment, the winding mechanism 8 is disposed in the accommodation space portion S provided as a post-exposure buffer on the downstream side of the conveyance path of the exposure engine 7. Thus, since the paper P is wound up, the capacity of the post-exposure buffer can be sufficiently increased without enlarging the accommodation space S. Accordingly, even when printing an extremely long size (for example, 430.1 mm or more) while reducing the size of the entire apparatus, the leading edge of the paper P being exposed does not reach the development processing unit, and the development processing is performed. It is possible to prevent the occurrence of uneven exposure due to the above.

  Moreover, since the paper P sent from the exposure engine 7 is wound up with a certain amount of slack or moved downward, the paper P is wound up and stored in this way. Even when a load fluctuation is applied, large vibrations or load fluctuations are not transmitted to the exposed portion of the paper P, and exposure unevenness does not occur.

  Furthermore, when the slack of the paper P that is wound up becomes large and hangs down from the winding drum 20 to a certain extent, the paper P is immediately wound up to eliminate the slack. Further, it is possible to prevent dust such as paper dust accumulated on the bottom surface of the apparatus from adhering to the emulsion surface of the paper P, thereby preventing the development failure.

  Note that the configuration of the image forming apparatus A according to the present invention is not limited to the above-described embodiment, and includes various other configurations. That is, in the above-described embodiment, the winding operation of the paper P by the winding mechanism 8 is intermittently performed so that the paper P sent from the exposure engine 7 sags. Instead, the paper P may be wound at a lower speed than the feed speed from the exposure engine 7, and the winding speed may be increased at the time of detection by the sag detection sensor 22.

  In the above-described embodiment, the sag detection sensor 22 is provided below the take-up drum 20 to detect the sagging paper P on the lower side. However, the sag detection sensor 22 is not limited to this. The slack of the paper P spreading outward from the drum 20 may be detected by providing it on the side of the winding drum 20 or in some cases upward.

  Further, it is not always necessary to provide the sag detection sensor 22, and the amount of slackness of the paper P is calculated from the feed amount from the exposure engine 7 and the like, and when this becomes larger than a predetermined value, the winding speed is increased (winding speed). (Including resumption).

  Furthermore, it is not always necessary to control the rotation of the take-up drum 20 as described above. For example, several thread-like holding members are provided below the take-up drum 20 at a predetermined height from the bottom of the apparatus. It is possible to suppress the dust from adhering to the paper P simply by bridging and holding the paper P.

  In the above-described embodiment, the exposure engine using laser light as the image forming unit has been described. However, the present invention is not limited to this. For example, an image exposure engine using a liquid crystal shutter may be used.

  As described above, the image forming apparatus according to the present invention secures a sufficient post-exposure buffer without winding up the entire apparatus by winding up and temporarily storing the leading edge of the paper being exposed. For example, it is particularly useful as an image forming apparatus for performing long printing.

It is explanatory drawing which shows schematic structure of the photographic processing system provided with the image forming apparatus. It is a figure which shows the structure of a storage space part. It is a detailed perspective view which shows the structure of a winding mechanism. It is sectional drawing of the cam mechanism which moves a pressurizing roller. FIG. 3 is a diagram illustrating a control block configuration of the image forming apparatus. 3 is a flowchart (first half) showing an operation of the image forming apparatus. 6 is a flowchart (second half) illustrating the operation of the image forming apparatus. FIG. 6 is a diagram illustrating an operation (part 1) of the image forming apparatus. FIG. 10 is a diagram illustrating an operation (No. 2) of the image forming apparatus. FIG. 10 is a diagram illustrating an operation (part 3) of the image forming apparatus. FIG. 10 is a diagram illustrating an operation (part 4) of the image forming apparatus. FIG. 10 is a diagram illustrating an operation (No. 5) of the image forming apparatus. FIG. 10 is a diagram illustrating an operation (No. 6) of the image forming apparatus. It is a figure which shows the structure of the image forming apparatus which concerns on a prior art.

Explanation of symbols

A Image forming apparatus S Accommodating space P Paper (image forming medium)
7 Exposure engine (image forming unit)
8 Winding Mechanisms 9a, 9b Exposure Transport Roller 11 First Transport Unit 12 Second Transport Unit 13 Winding Moving Mechanism 20 Winding Drum 21 Pressure Roller 22 Sag Detection Sensor (Optical Sensor)
22a Light emitting element 22b Light receiving element 44 Drum rotation control means (winding speed control means)

Claims (4)

An image forming apparatus configured to cut an image forming medium wound in a roll shape into a predetermined length, scan and expose the image forming medium while conveying the image forming medium, and then convey the image forming medium to the development processing unit. There,
The upper limit of the length in the conveyance direction of the image forming medium that can be processed in the image forming unit is not less than the conveyance distance from the image forming unit to the development processing unit,
A winding storage unit that winds up and temporarily stores the image forming medium carried out from the image forming unit, and an adhesion suppression unit that suppresses the adhesion of dust to the image forming medium wound up in the winding storage unit. And an image forming apparatus. The image forming apparatus according to claim 1.
The take-up storage unit includes a take-up drum for taking up the image forming medium and a storage space for receiving the take-up drum, and stores the image forming medium so as to cause a sag in the image forming medium carried out from the image forming unit. Is to wind up,
The adhesion suppressing means adjusts the winding speed of the image forming medium so that the image forming medium that sags outside the winding drum does not come into contact with the wall surface of the winding storage unit facing the housing space. An image forming apparatus, comprising: The image forming apparatus according to claim 2.
The adhesion suppressing means includes an optical sensor provided to detect an image forming medium that sags outward from the take-up drum in a state of being separated from the wall surface of the take-up storage unit, and an image according to a signal from the sensor. A winding speed control means for increasing the winding speed when detecting the forming medium, and
The sensor includes a light emitting element and a light receiving element arranged opposite to each other in a direction intersecting the rotation axis direction outside the winding drum, and both elements are offset from each other in the rotation axis direction. An image forming apparatus. The image forming apparatus according to claim 1.
The take-up storage unit includes a take-up drum for taking up the image forming medium and a storage space for receiving the take-up drum, and stores the image forming medium so as to cause a sag in the image forming medium carried out from the image forming unit. Is to wind up,
The adhesion suppressing means includes a thread-like holding member constructed so as to hold the lower end portion of the image forming medium that hangs outward from the take-up drum away from the bottom surface of the take-up storage portion facing the housing space portion. An image forming apparatus.

Images