JP3693019B2 - Plate making machine exposure table equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exposure table apparatus used for exposing a document image on the surface of a recording sheet, and more particularly to an exposure table apparatus suitable for a plate making machine using a photosensitive sheet roll.
[0002]
[Background]
For example, as disclosed in Japanese Patent No. 2669302, which is an application of the present patent applicant, in a plate making machine that creates a printing master as a printing original plate, an exposure table apparatus as shown in FIG. 6 is a photosensitive master. This is used to expose a document image on the surface of a sheet (recording sheet) X.
That is, this exposure table apparatus includes a vacuum box B in which a vacuum pressure is applied to the inside by a blower A, and an endless porous adsorbing belt capable of adsorbing a master sheet X with the vacuum pressure in the vacuum box B opened on one side. C is provided. The exposure table apparatus is provided with a master sensor D capable of detecting the front end of the master sheet X and a pair of master stoppers E facing in the width direction capable of locking the front end surface of the master sensor D. The orientation of the tilted master sheet X is corrected by locking the front end of the master sheet X.
[0003]
By the way, as described in the above-mentioned patent gazette, in a recent plate making machine, a master sheet roll wound around a bobbin is used, and a web-like photosensitive sheet drawn out from the master sheet roll is cut and used as a master sheet X. However, the master sheet roll wound around the bobbin has a “winding gusset”, and there is a problem that the master sheet X cut by the “winding gusset” curls in a natural arc shape. In other words, this “roll gusset” is particularly problematic in the recently developed resin sheet base and aluminum foil base, which are recently developed compared to paper-based zinc oxide paper.
More specifically, in the above-described exposure table apparatus, when the master sheet X having strong stiffness “rolling” is conveyed by the porous adsorption belt C, if the vacuum pressure in the vacuum box B is weak, as shown in FIG. In addition, the master sheet X is lifted from the porous adsorption belt C due to the “winding”, the flatness of the master sheet X is lowered, and the quality of the exposed image is deteriorated.
[0004]
[Problems to be solved by the invention]
For this reason, in an exposure table apparatus that handles a master sheet X having a stiff "rolling", the vacuum pressure in the vacuum box B is increased and the entire surface of the master sheet X is strongly adsorbed on the surface of the porous adsorption belt C. Although measures to maintain the flatness of the sheet X are taken, this vacuum pressure strengthening measure causes a new problem when the master sheet X is conveyed while being inclined.
That is, when the vacuum pressure is increased to bring the entire surface of the master sheet X into close contact with the surface of the porous adsorption belt C, when the master sheet X is conveyed while being tilted, the front end of the master sheet X is placed on one master stopper E. Even if the inclination of the entire master sheet is corrected, the inclination of the entire master sheet is not adjusted due to the strong adhesion of the master sheet X to the porous adsorption belt over the entire surface. As shown in FIG. Only a part of the master sheet X that hits the surface is in a state of being lifted from the surface of the porous adsorption belt C by the “winding gusset”.
[0005]
That is, when such a local “scaling state” of the master sheet X occurs, not only the tilt correction function of the master stopper E itself is invalidated, but also the exposure image “distortion” is caused, and the master image It causes quality degradation.
[0006]
The object of the present invention is to solve the problems of the exposure table apparatus of the conventional plate making machine as described above, and even if the recording sheet is stiff and easy to curl, the inclination correction is reliably performed by the stopper, and the original image An object of the present invention is to provide an exposure table apparatus for a plate making machine that can maintain the flatness of an exposure character recording sheet.
[0007]
[Means for Solving the Problems]
In order to achieve this object, the present invention provides an endless porous adsorption belt in a vacuum box to convey a recording sheet cut from a photosensitive sheet roll, and locks the leading end of the recording sheet to correct the inclination. In the exposure table apparatus of the plate making machine provided with a stopper, the inside of the vacuum box is partitioned as a plurality of chambers adjacent to each other in the recording sheet feeding direction and the internal vacuum pressure can be controlled independently, and when the recording sheet is locked by the stopper, An exposure table apparatus for a plate making machine is proposed in which the vacuum pressure in chambers other than the chamber corresponding to the master stopper is temporarily reduced, and the vacuum pressure in the chamber is increased after the recording sheet is stopped.
[0008]
In the description of the preferred embodiments of the invention described below,
1) The stoppers are a pair of rod-shaped stoppers facing in a direction perpendicular to the recording sheet conveyance direction, and the inside of the vacuum box includes three of the first to third chambers in the order of the recording sheet conveyance direction. When the recording sheet is taken into the exposure table apparatus, first, vacuum pressure is applied to all the chambers, and the first and the second recording sheets are recorded by the recording sheet recording signal of the master sensor provided at the third chamber position. Only the vacuum pressure in the second chamber is temporarily reduced, and after the recording sheet is completely stopped by stopping the porous adsorption belt and stopping the stopper, the vacuum pressure in the first and second chambers is increased to convey the recording sheet. The rear end of the direction is adsorbed on the surface of the porous adsorption belt, and the adsorption state of the entire recording sheet to the porous adsorption belt is maintained and the adsorption state of the entire recording sheet to the porous adsorption belt is maintained. Exposure stage device of plate making machine which performs exposure of the recording sheet is described.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a plate making machine to which the present invention is applied shown in the drawings will be described below.
FIG. 1 shows an overall cross section of a digital plate making machine capable of processing a digital image or an original image as required. First, master sheet rolls of different sizes can be mounted on the lower right portion of the machine body 1 capable of shielding external light. A paper feeding device 2A and a second paper feeding device 2B are incorporated.
[0010]
The first sheet feeding device 2A and the second sheet feeding device 2B are designated as a detachable mounting drum 2a to which a master sheet roll can be attached, a feeding roller 2b for pulling out the leading end of the master sheet X, and the master sheet X. A cutter 2c that cuts into length and a sheet feed roller 2d are provided, and the cut master sheet X passes through the first path 3a and the second path 3b, and is located above the first sheet feeder 2A. 3 is sent out.
A charging electrode unit 4 for charging the master sheet X is provided in the middle of the paper feed path 3, and the master sheet X that has passed through the charging electrode unit 4 is centered at the upper part of the machine body 1 that is driven at a sub-scanning speed. The feed roll 5 is supplied.
A laser scanning unit 6 that scans an original image in a main operation direction perpendicular to the paper surface of FIG. 1 is positioned above the paper feed path 3, and a digital image from a computer (not shown) is displayed on the laser scanning unit. The surface of the feed roll 5 is scanned from 6.
[0011]
The original image is beam-scanned from the laser scanning unit 6 on the surface of the master sheet X positioned on the feed roll 5 while the feed roll 5 is rotating at a controlled speed, and the original image is formed into a latent image on the photosensitive surface of the master sheet X by the scanning. However, the latent image forming master sheet X passes through the intermediate guide unit 7 and is supplied to the exposure table device 8 arranged in a substantially vertical direction at a substantially central portion of the machine unit 1. It is delivered to the wet developing device 9 at the lower left.
A document table 10 for optically capturing a document image is provided at the upper left of the machine body 1, and an image of the document on the document table 10 is projected onto the surface of the exposure table device 8 using an exposure optical system 11. The That is, the illustrated exposure optical system 11 includes an illumination lamp 11a that illuminates a document table 10 on which a document is set, a projection lens 11b that forms a document image on the surface of the exposure table 8a, and a mirror 11c.
[0012]
The above-described wet developing device 9 has a developer nozzle 13 for ejecting a developer onto the developing pallet 12 through which the master sheet X passes, and is below the developing pallet 12 inclined downward in the conveying direction of the master sheet X. Has a developer tank 14 for collecting the developer.
Further, a squeezing roller device 15 is located at the rear end of the developing pallet 12, and excess developer on the surface of the master sheet X is removed by the rotational movement of the squeezing roller described later of the squeezing roller device 15. .
[0013]
The master sheet X on which the original image has been developed is dried by the heat fixing device 16 adjacent to the outlet side of the wet developing device 7 to fix the toner image, and is discharged by a discharge roller 17 provided at the lower left portion of the machine body 1. It will be collected on the collection tray 18 outside the body 1.
[0014]
2 to 4 show the details of the above-described exposure table apparatus 8. The exposure table apparatus 8 includes a vacuum box 21 whose surface is opposed to the exposure optical system 11, and the inside of the vacuum box 21 is horizontal. Are divided into a first chamber 25, a second chamber 26, and a third chamber 27 adjacent to each other in the conveying direction of the master sheet X by two partition walls 23, 24 in the direction.
In addition, as shown in FIG. 4, on the back surface of the vacuum box 21, three pairs of first blower 31, second blower 32, and second pair corresponding to the first chamber 25, the second chamber 26, and the third chamber 27 are provided. 3 blowers 33 are installed, and the first blower motors 31 a, 32 a, 33 a of the first blower 31, the second blower 32, and the third blower 33 correspond to the insides of the first chamber 25, the second chamber 26, and the third chamber 27. The vacuum pressure is controlled independently.
[0015]
2 and 3, a pair of belt drive rollers 35 and 36 are installed above and below the vacuum box 21, and the master sheet X is attracted and conveyed between these belt drive rollers 35 and 36. A porous adsorbing belt 37 is formed. These belt drive rollers 35 and 36 are respectively driven by drive belts 43 and 44 whose rotation is controlled by a belt conveying motor 41 shown in FIG.
[0016]
A master sensor 45 for detecting the leading edge of the master sheet X to be conveyed is positioned at the center in the width direction of the exposure table 8 near the upper portion of the third chamber 27, and a belt conveyance motor is detected by a master detection signal from the master sensor 45. 41 and the blower motors 31a, 32a, and 33a are controlled. Details of these control timings will be apparent from the following description using the flowchart of FIG.
[0017]
In addition, a pair of master stoppers 47 and 48 facing the width direction of the exposure table device 8 are disposed at a position near the lower portion of the third chamber 27, and the exposure table is inclined and conveyed by these master stoppers 47 and 48. The inclination of the device 8 is corrected.
That is, as shown in FIG. 3, both master stoppers 47 and 48 are supported so as to be able to protrude and retract with respect to the vacuum box 21, and intermediate portions of these master stoppers 47 and 48 are pivotally supported by the vacuum box 21. One side 51a of the bell crank 51 is engaged, and the other side of the bell crank 51b is operated by an electromagnetic solenoid 53 excited at the end of exposure.
[0018]
Next, processing of the master sheet X in the exposure table apparatus 8 will be described in detail using the flowchart shown in FIG.
First, at the start of printing, when the belt conveyance motor 41 is started to rotate and the porous adsorption belt 37 is driven, all the blower motors 31a, 31a, 32b of the first blower 31, the second blower 32, and the third blower 33 are simultaneously started. 32a and 33a are driven, and the electromagnetic solenoid 53 is excited, so that the master stoppers 47 and 48 are in a protruding state (step S1). For this reason, since the internal vacuum pressures of all of the first chamber 25, the second chamber 26, and the third chamber 27 are increased, the entire surface of the master sheet X is strongly strengthened along with the feed movement of the porous adsorption belt 37. And is taken in on the surface of the exposure table 8. Therefore, even if the master sheet X is easily curled, the master sheet X is transported in a state where the flatness is maintained without being lifted from the surface of the porous adsorption belt 37.
[0019]
Next, when the master sheet X is sufficiently taken into the exposure table 8 and the master sensor 45 detects the leading edge of the master sheet X (step S2), the blower motors corresponding to the first chamber 25 and the second chamber 26 are stopped. (Step S3). For this reason, since the vacuum pressure inside the first chamber 25 and the second chamber 26 is reduced, the adsorbing force with respect to the portion other than the front end portion of the master sheet X at the position of the third chamber 27 is weakened.
[0020]
Thereafter, a time until the leading edge of the master sheet X reaches the position of the master stoppers 47 and 48 is waited (step S4).
During this waiting time, as shown by a two-dot chain line in FIG. 2, when the master sheet X is conveyed in an inclined state, the leading edge of the master sheet X first comes into contact with one of the master stoppers 47 and 48. The couple in the direction of the arrow acts on the master sheet X.
As a result, since the master sheet X is adsorbed by the porous adsorbing belt 37 only at the front end portion of the master sheet X, the master sheet X is inclined by the same couple and is in an inclination correction state as indicated by a one-dot chain line.
[0021]
When the belt conveyance motor 41 is stopped after the inclination correction waiting time has elapsed, the blower motors of the first blower 31 and the second blower 32 are energized again (step S5), and the master sheet X is stopped. By increasing the vacuum pressure of the first blower 31 and the second blower 32, the entire surface of the master sheet X is strongly adsorbed to the surface of the porous adsorption belt 37, and part of the float is prevented, and the flatness of the master sheet X is secured.
[0022]
Next, after waiting for the entire surface of the master sheet X to be attracted (step S6), the electromagnetic solenoid 53 is excited and the master stoppers 47 and 48 are retracted into the vacuum box 21 to complete the preparation for exposure (step S7).
Waiting for the time until the master stoppers 47 and 48 are completely retracted (step S8), the illumination lamp 11a is turned on (step S9), the original image is exposed for a predetermined time (step S10), and the illumination lamp 11a is turned on. The light is turned off (step S11).
[0023]
Waiting for the illumination lamp 11a to be completely turned off (step S12), the belt conveyance motor 41 is energized again (step S13), and the master sheet X is discharged from the position by driving the porous adsorption belt 37. In step S14), the belt conveying motor 41 is stopped, and the blower motors 31a, 32a, 33a of all the first blower 31, the second blower 32, and the third blower 33 are stopped to complete the exposure process.
[0024]
In the above-described embodiments of the present invention, the exposure table apparatus applied to the plate making machine has been described. However, the exposure table apparatus can be implemented as an exposure table apparatus for other devices that expose an image on a recording sheet. Further, in the same embodiment, an example in which the chamber is divided into three chambers has been described. However, the present invention is not limited to three divisions, and the master stoppers 47 and 48 are also exemplified as a pair of rods. A ruler-shaped stopper extending in the width direction of the master sheet X may be used.
[0025]
【The invention's effect】
As is apparent from the above description, according to the present invention, an exposure table apparatus capable of maintaining the flatness of the recording sheet (master sheet) having “rolling gusset” that is easily curled and maintaining the tilt correcting function is obtained. Can do.
[Brief description of the drawings]
FIG. 1 is an overall sectional view of a plate making machine according to the present invention.
FIG. 2 is a front view of an exposure table device used in the plate making machine.
FIG. 3 is a sectional view of the exposure table apparatus.
FIG. 4 is a rear view of the exposure table apparatus.
FIG. 5 is a control flow of the exposure table apparatus.
FIG. 6 is an explanatory diagram of a conventional exposure table apparatus in the case of a master sheet with strong curl.
FIG. 7 is an explanatory diagram of the exposure table apparatus when the tilted master sheet is stopped.
[Explanation of symbols]
X Master sheet 8 Exposure table device 21 Vacuum box 23, 24 Partition wall 25 First chamber 26 Second chamber 27 Third chamber 31 First blower 32 Second blower 33 Third blower 37 Porous adsorption belt 41 Belt transport motor 45 Master sensor 47, 48 Master stopper 53 Electromagnetic solenoid

Claims (2)

In the exposure table apparatus of the plate making machine provided with an endless porous adsorption belt in a vacuum box to convey a recording sheet cut from a photosensitive sheet roll, and to provide a stopper for correcting the inclination by locking the tip of the recording sheet, The inside of the vacuum box is divided into a plurality of chambers adjacent to each other in the recording sheet feeding direction and the internal vacuum pressure can be controlled independently. When the recording sheet is locked by the stopper, the vacuum pressures of the chambers other than the chamber corresponding to the master stopper are temporarily reduces the after cessation of the recording sheet, an exposure stage device of plate making machine, characterized in that to increase the vacuum pressure of the chamber. The stoppers are a pair of rod-like stoppers facing in a direction perpendicular to the recording sheet conveyance direction, and the inside of the vacuum box has three chambers of first to third chambers in order of the recording sheet conveyance direction. When the recording sheet is taken into the exposure stand apparatus, first, vacuum pressure is applied to all the chambers, and the first and second recording sheet recording signals of the master sensor provided at the third chamber position are used. Only the vacuum pressure in the chamber is temporarily reduced, and after the recording sheet is completely stopped by stopping the porous adsorption belt and stopping the stopper, the vacuum pressure in the first and second chambers is increased and after the recording sheet is conveyed. The edge is adsorbed on the surface of the porous adsorption belt, and the recording sheet is kept in the adsorption state on the porous adsorption belt and the recording sheet is kept in the adsorption state on the porous adsorption belt. Plate making machine exposure table apparatus according to claim 1, characterized in that the exposure of over bets.

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