JP3573277B2 - Plate material adsorption mechanism - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plate material suction mechanism, and more particularly, to a plate outer surface scanning type image recording apparatus that records a two-dimensional image on a plate material wound around a drum, and applies the plate material on an outer peripheral surface of the drum. The present invention relates to a plate material adsorption mechanism for adsorbing and fixing a plate.
[0002]
[Prior art]
Conventionally, while rotating a cylindrical drum, a drawing unit that irradiates a laser beam modulated by an image signal toward the drum is moved in parallel with the rotation axis of the drum, so that a plate material wound around the drum is moved. 2. Description of the Related Art A cylindrical outer surface scanning type image recording apparatus for recording a two-dimensional image is known. Alternatively, a plate material is suction-fixed to the inner peripheral surface of a semi-cylindrical drum, and a drawing unit that irradiates the fixed plate material with laser light modulated by an image signal is moved in parallel with the center axis of the drum. An image recording apparatus of a cylindrical inner surface scanning type that records a two-dimensional image on a plate material fixed to the inner peripheral surface of a drum is known.
[0003]
FIG. 6 is a diagram showing the overall configuration of a conventional cylindrical outer surface scanning type image recording apparatus. In FIG. 6, a sheet-shaped printing plate 2 is wound around an outer peripheral surface 1a of a drum 1. The plate 2 is typically made of an aluminum plate, and has a surface coated with a photosensitive material. The drum 1 is driven by the main scanning motor 3 together with the plate material 2 and is rotated at a constant speed in the main scanning direction X.
[0004]
In the drum 1, a blower 4 is attached near an end opposite to the main scanning motor 3. The drum 1 and the blower 4 constitute a plate material sucking mechanism for sucking and fixing the plate material 2 on the outer peripheral surface 1a of the drum 1. That is, a large number of suction holes (not shown) are provided in the area on the outer peripheral surface 1a of the drum 1 where the plate material 2 is wound. The blower 4 sucks the air in the drum 1 and discharges the air to the outside. In this way, the blower 4 sucks and discharges the air in the drum 1 to create a pressure difference between the inside and outside of the drum 1. As a result, the printing plate 2 is fixed to the outer peripheral surface 1 a of the drum by suction.
[0005]
The drawing unit 5 receives the image data 12 and outputs a laser beam modulated by the image data 12 to the drum 1. The laser light scans the printing material 2 wound on the outer peripheral surface 1 a thereof in the main scanning direction X by the rotation of the drum 1. The drawing unit 5 is moved at a constant speed on a rail (not shown) by a sub-scanning feed screw 8 driven to rotate by a sub-scanning motor 7. For this reason, the laser beam scans the plate material 2 along the sub-scanning direction Y. Therefore, a two-dimensional image having a spread in the main scanning direction X and the sub-scanning direction Y is formed on the plate 2. Printing is performed using the plate material 2 on which an image is formed (this is called a printing plate).
[0006]
[Problems to be solved by the invention]
Recently, plate materials of various sizes are provided, and image recording apparatuses are required to be able to handle plate materials of any size. For example, in the conventional image recording apparatus configured as described above, the maximum size and the minimum size of the usable plate 2 are determined, and an image is recorded on the plate 2 of an arbitrary size between them. Can be. Here, attention is paid to a problem that the strength of adsorbing the plate material 2 to the outer peripheral surface 1a of the drum is insufficient depending on the size of the plate material 2.
[0007]
FIG. 7 is a developed view of the outer peripheral surface 1a of the drum shown in FIG. In FIG. 7, an area 21 surrounded by a dotted line is an area around which the maximum size plate 2 is wound, and an area 22 is an area around which the minimum size plate 2 is wound.
[0008]
In the conventional plate suction mechanism, as shown in FIG. 7, a large number of suction holes 23 are provided evenly in an area 21 around which a plate material 2 of the maximum size is wound on the outer peripheral surface 1a of the drum. Further, a groove 24 passing through each suction hole 23 is formed, and the suction force from each suction hole 23 expands two-dimensionally (that is, the plate material 2 is linearly sucked). As compared with the point adsorption, the plate material 2 is more firmly adsorbed and fixed. Therefore, if the rotation speed of the drum 1 is not so high, the plate material 2 of any size within the range from the minimum size to the maximum size can be fixed on the outer peripheral surface 1a of the drum by the suction force of the blower 4. it can.
[0009]
However, when the plate 2 having a size smaller than the maximum is used, a phenomenon occurs in which a large amount of air enters the drum 1 from the suction holes 23 (leakage holes) not covered by the plate 2. When air enters the drum 1 through the leak hole, the pressure difference between the inside and the outside of the drum 1 becomes small, and as a result, the strength of the plate material 2 adsorbed on the outer peripheral surface 1a becomes insufficient. If the suction strength is insufficient, when the drum 1 is rotated at high speed, the drum 1 cannot withstand the centrifugal force applied to the plate material 1 in the radial direction r (that is, the direction from the center of the drum 1 to the outer peripheral surface 11a). The plate material 2 may fall off the outer peripheral surface 1a of the drum.
[0010]
In order to solve the shortage of the adsorption strength due to the presence of the leak hole, for example, it is conceivable to use a blower 4 having a stronger suction force, which more than compensates for the intrusion of air from the leak hole. Alternatively, the inside of the drum may be divided into a plurality of rooms so that the suction force of the blower 4 does not reach the room below the leak hole.
[0011]
However, in the former method, since the blower 4 having a strong suction force is used, the price of the plate material suction mechanism increases, and wasteful power consumption occurs. In the latter method, the interior of the drum 1 is divided into a plurality of rooms, a valve is provided in each room, and a mechanism and a control circuit for opening and closing the valve according to the size of the plate material are also required. Is complicated, and it is inevitable that the price of the plate material suction mechanism is significantly increased.
[0012]
Therefore, an object of the present invention is to provide an inexpensive cylindrical outer surface scanning type image recording apparatus capable of strongly adsorbing and fixing plate materials of various sizes to the outer peripheral surface of a drum with the same suction force as before. An object of the present invention is to provide a plate material suction mechanism.
[0013]
Means for Solving the Problems and Effects of the Invention
A first invention is used in a cylindrical outer surface scanning type image recording apparatus that records a two-dimensional image on a plate material wound around a drum, and a plate material adsorption mechanism for adsorbing and fixing the plate material on an outer peripheral surface of the drum. And
The inside of the drum is hollow, a cylindrical drum having a plurality of suction holes formed on the outer peripheral surface thereof, and a blower that sucks air from the inside of the drum and discharges the air to the outside,
On the outer peripheral surface of the drum,
A first area around which the smallest plate is wound;
A second area including the first area and around which the plate material of the maximum size is wound is determined,
A suction hole having a smaller diameter is provided in the second area excluding the first area as compared with the first area.
[0014]
According to the first aspect of the invention, when a plate material having a size smaller than the maximum is used, air enters the drum from suction holes (leak holes) not covered by the plate material, but the diameter of the leak holes is smaller than before. In addition, the amount of air entering can be reduced. For this reason, even if the suction force of the blower is the same as in the related art, the pressure difference between the inside and outside of the drum is kept large, and the strength of the plate material adsorbed on the outer peripheral surface of the drum becomes higher than before. As a result, when the drum is rotated at a high speed, the risk of the plate material falling off from the outer peripheral surface of the drum is reduced.
[0015]
Here, the suction holes are typically formed in a right circular column shape as in the second invention described below, but may be formed in a polygonal column shape such as a quadrangular column or a hexagonal column.
[0016]
In a second aspect, in the first aspect,
Each suction hole is formed in a right cylindrical shape.
[0017]
In the second aspect, the suction hole can be easily formed by the drill.
[0018]
Here, when the suction hole is formed by a drill as in the second aspect of the present invention, the smaller the hole diameter and the deeper the hole, the longer the elongated drill is required. Therefore, when forming a small-diameter suction hole provided in the second area excluding the first area, the danger of drill breakage increases. In order to avoid such a danger, for example, a suction hole may be provided with a step, as in the third invention described below.
[0019]
In a third aspect, in the second aspect,
A suction hole provided in a second area excluding the first area has a first right cylindrical portion near the outer peripheral surface of the drum and a suction hole near the inner peripheral surface opposite to the outer peripheral surface. Consisting of two right circular cylinders,
The first right cylindrical portion has the same diameter as the suction hole provided in the first area, and only the second right cylindrical portion has a diameter larger than that of the suction hole provided in the first area. It has a small diameter.
[0020]
In the third aspect, when forming a small-diameter suction hole provided in the second area excluding the first area, first, a hole having a large diameter is drilled from the outer peripheral surface to a predetermined depth. Then, the hole may be further drilled with a small diameter drill from the bottom surface to the inner peripheral surface of the hole, so that the risk of drill breakage is reduced. Then, in the case of the suction hole having a step formed in this way, the narrow portion is shorter in comparison with the suction hole formed in the shape of a slender right circular cylinder, but when the hole becomes a leak hole, it is inserted into the drum from there. Since there is not much difference in the amount of air that enters, the adsorbing power does not decrease.
[0021]
In a fourth aspect based on the first aspect,
In the second area excluding the first area, suction holes are provided at a lower density than in the first area.
[0022]
In the fourth aspect of the invention, in addition to the diameter of the leak hole being smaller than that of the related art, the density of the leak hole is made smaller than that of the related art, so that the amount of air entering the drum can be further reduced. Therefore, the strength with which the plate material is attracted to the outer peripheral surface of the drum is further increased, and as a result, when the drum is rotated at a high speed, the risk of the plate material falling off the outer peripheral surface of the drum is greatly reduced.
[0023]
According to a fifth aspect, in the first or fourth aspect,
A suction groove passing through each suction hole is formed on the outer peripheral surface of the drum.
[0024]
In the fifth aspect, since the suction groove is formed, the suction force from the suction hole is two-dimensionally expanded (that is, the plate material is linearly sucked). The material is more firmly adsorbed and fixed, and as a result, the risk of the plate material falling off is further reduced.
[0025]
A sixth invention is used in an image recording apparatus of a cylindrical outer surface scanning type for recording a two-dimensional image on a plate material wound around a drum, and a plate material suction mechanism for sucking and fixing the plate material on the outer peripheral surface of the drum. And
The inside of the drum is hollow, a cylindrical drum having a plurality of suction holes formed on the outer peripheral surface thereof, and a blower that sucks air from the inside of the drum and discharges the air to the outside,
On the outer peripheral surface of the drum,
A first area around which the smallest plate is wound;
A second area including the first area and around which the plate material of the maximum size is wound is determined,
In the second area excluding the first area, suction holes are provided at a lower density than in the first area.
[0026]
According to the sixth aspect of the present invention, when a printing plate having a size smaller than the maximum is used, air enters the drum through suction holes (leakage holes) not covered by the plate material, but the number of leaking holes is smaller than in the past. In addition, the amount of air entering can be reduced. For this reason, even if the suction force of the blower is the same as in the related art, the pressure difference between the inside and outside of the drum is kept large, and the strength of the plate material adsorbed on the outer peripheral surface of the drum becomes higher than before. As a result, when the drum is rotated at a high speed, the risk of the plate material falling off from the outer peripheral surface of the drum is reduced.
[0027]
In the seventh invention, the drawing unit that irradiates the drum with laser light modulated by an image signal is moved in parallel with the rotation axis of the drum while rotating the cylindrical drum, thereby being wound around the drum. A cylindrical outer surface scanning type image recording apparatus for recording a two-dimensional image on a plate material,
A cylindrical drum having a hollow inside and a plurality of suction holes formed on an outer peripheral surface thereof,
A first drive for rotating the drum,
A blower that sucks air from inside the drum and discharges it to the outside,
A drawing unit that irradiates a laser beam modulated with an image signal toward the drum, and a second drive unit that moves the drawing unit in parallel with the rotation axis of the drum,
On the outer peripheral surface of the drum,
A first area around which the smallest plate is wound;
A second area including the first area and around which the plate material of the maximum size is wound is determined,
A suction hole having a smaller diameter is provided in the second area excluding the first area as compared with the first area.
[0028]
In the seventh aspect of the invention, the plate material suction mechanism according to the first aspect of the invention is used in order to suction-fix the plate material on the outer peripheral surface of the drum.
[0029]
According to an eighth aspect of the present invention, the drawing unit that irradiates the drum with laser light modulated by an image signal is moved in parallel with the rotation axis of the drum while rotating the cylindrical drum, so that the drum is wound around the drum. A cylindrical outer surface scanning type image recording apparatus for recording a two-dimensional image on a plate material,
A cylindrical drum having a hollow inside and a plurality of suction holes formed on an outer peripheral surface thereof,
A first drive for rotating the drum,
A blower that sucks air from inside the drum and discharges it to the outside,
A drawing unit that irradiates a laser beam modulated with an image signal toward the drum, and a second drive unit that moves the drawing unit in parallel with the rotation axis of the drum,
On the outer peripheral surface of the drum,
A first area around which the smallest plate is wound;
A second area including the first area and around which the plate material of the maximum size is wound is determined,
In the second area excluding the first area, suction holes are provided at a lower density than in the first area.
[0030]
In the eighth invention, the plate material suction mechanism according to the sixth invention is used in order to suction-fix the plate material on the outer peripheral surface of the drum.
[0031]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing an overall configuration of a cylindrical outer surface scanning type image recording apparatus using a plate material suction mechanism according to an embodiment of the present invention. The image recording apparatus shown in FIG. 1 includes a drum 11 instead of the drum 1 in the image recording apparatus shown in FIG. The components other than the drum 11 and its outer peripheral surface 11a are the same as those in the related art, and are denoted by the same reference numerals as in FIG.
[0032]
In FIG. 1, a sheet-shaped printing plate 2 is wound around an outer peripheral surface 11 a of a drum 11. The plate 2 is typically made of an aluminum plate, and has a surface coated with a photosensitive material. The drum 11 is driven by the main scanning motor 3 together with the printing plate 2, and is rotated at a constant speed in the main scanning direction X.
[0033]
In the drum 11, a blower 4 is attached near an end opposite to the main scanning motor 3. The drum 11 and the blower 4 constitute a plate material suction mechanism according to an embodiment of the present invention. In this plate material suction mechanism, a large number of suction holes (not shown) are provided in an area of the outer peripheral surface 11a of the drum 11 where the plate material 2 is wound, and the blower 4 sucks and discharges the air in the drum 11. As a result, a pressure difference occurs between the inside and outside of the drum 11, and as a result, the printing plate 2 is suction-fixed to the outer peripheral surface 11a of the drum.
[0034]
The drawing unit 5 receives the image data 12 and outputs the laser light modulated by the image data 12 to the drum 11. The laser light scans the plate material 2 wound on the outer peripheral surface 11 a thereof in the main scanning direction X by the rotation of the drum 11. The drawing unit 5 is moved at a constant speed on a rail (not shown) by a sub-scanning feed screw 8 driven to rotate by a sub-scanning motor 7. For this reason, the laser beam scans the plate material 2 along the sub-scanning direction Y. Therefore, a two-dimensional image having a spread in the main scanning direction X and the sub-scanning direction Y is formed on the plate 2. Printing is performed using the plate material 2 on which an image is formed in this manner. The basic configuration and operation of the image recording apparatus described above are the same as those of the related art.
[0035]
In the image recording apparatus configured as described above, the maximum size and the minimum size of the usable plate material 2 are determined, and an image can be recorded on the plate material 2 of any size between them. In addition, the problem that the strength of the plate material 2 being absorbed by the outer peripheral surface 1a of the drum due to the size of the plate material 2, which has been a problem in the related art, is solved as follows.
[0036]
FIG. 2 is a diagram showing the outer peripheral surface 11a of the drum 11 shown in FIG. In FIG. 2, an area 21 surrounded by a dotted line is an area around which the maximum size plate 2 is wound, as in FIG. 7, and an area 22 is an area around which the minimum size plate 2 is wound.
[0037]
In the drum outer peripheral surface 11a of the present image recording apparatus configured as described above, as shown in FIG. 2, a large number of suction holes (23, 23a) are provided in an area 21 around which the plate material 2 of the maximum size is wound. Have been. Accordingly, a plate material 2 of an arbitrary size can be fixed to the outer peripheral surface 11a of the drum by the suction force of the blower 4 within a range from a predetermined minimum size to a predetermined maximum size. This is the same as the drum outer peripheral surface 1a of the conventional image recording apparatus.
[0038]
Features unique to the drum outer peripheral surface 11a of the present image recording apparatus and not present in the drum outer peripheral surface 1a of the conventional image recording apparatus (see FIG. 7) are mainly the following (1) and (2).
[0039]
(1) In the area 21 (except for the area 22) around which the plate material 2 of the maximum size is wound, the suction holes 23a have a lower density (for example, in the area 22 where the plate material 2 of the minimum size is wound). (About two thirds of the area 22). That is, assuming that the suction holes 23 are provided in the area 22 at the same density as in the related art, the suction holes 23a are provided in the area 21 (excluding the area 22) at a lower density than in the related art.
[0040]
Thus, when the plate material 2 having a size smaller than the maximum is used, air enters the drum 11 from the suction holes 23a (leak holes) not covered by the plate material 2, but the number of leak holes is smaller than in the past. In addition, the amount of air entering can be reduced. Therefore, despite the use of the same blower 4 as in the past, the pressure difference between the inside and outside of the drum 11 is kept large, and the strength with which the plate material 2 is adsorbed on the outer peripheral surface 11a becomes higher than in the past.
[0041]
(2) A suction hole 23a having a smaller diameter is provided in the area 21 around which the maximum size plate 2 is wound (except in the area 22), as compared with the area 22 where the minimum size plate 2 is wound. ing. That is, assuming that the suction holes 23 having the same diameter as the conventional one are provided in the area 22, the suction holes 23a having a smaller diameter than the conventional one are provided in the area 21 (excluding the area 22). .
[0042]
Thus, when the plate material 2 having a size smaller than the maximum is used, air enters the drum 11 from the suction holes 23a (leakage holes) not covered by the plate material 2, but the diameter of the leak holes is smaller than before. In addition, the amount of air entering can be reduced. Therefore, despite the use of the same blower 4 as in the past, the pressure difference between the inside and outside of the drum 11 is kept large, and the strength with which the plate material 2 is adsorbed on the outer peripheral surface 11a becomes higher than in the past.
[0043]
The present plate material suction mechanism has the above features (1) and (2), so that even if a leak hole is present on the drum outer peripheral surface 11 due to the use of the plate material 2 having a size smaller than the maximum size, the conventional plate material suction mechanism is different from the conventional one. A remarkably strong adsorption force can be obtained in comparison. As a result, in the cylindrical outer surface scanning type image recording apparatus using this mechanism, when the drum 11 is rotated at a high speed, the risk of the plate 2 falling off the outer peripheral surface 11a of the drum is greatly reduced.
[0044]
A feature other than the above (1) and (2) is that grooves (suction grooves 24a) passing through the suction holes (23, 23a) are formed on the outer peripheral surface 11a of the drum. By forming these suction grooves 24a, the suction force from each suction hole (23, 23a) is expanded two-dimensionally (that is, the plate material 2 is linearly sucked), and thus the suction holes (23, 23a) are formed. The plate material 2 is more firmly adsorbed and fixed as compared with the point adsorption by only the plate. In particular, the suction groove 24a has a unique pattern as shown in FIG. 2 in order to efficiently suction a plate material of any size from the maximum size to the minimum size. This further reduces the risk of plate material falling off.
[0045]
Here, a specific example of the structure of the suction hole 23a that can be a leak hole described in the above (2) will be described. FIG. 3 is a structural example (top and sectional views) of the suction hole 23 provided in the area 22 shown in FIG. FIG. 4 is a structural example (top view and cross-sectional view) of the suction hole 23a provided in the area 21 (excluding the area 22) shown in FIG. 2, that is, the suction hole 23a that can be a leak hole. In FIG. 3, the suction hole 23 has a diameter substantially equal to the width of the suction groove 24. In FIG. 4, the suction hole 23a has a diameter smaller than the width of the suction groove 24 (for example, approximately half the width of the suction groove 24).
[0046]
In the above, the description has been given of the image recording apparatus provided with the plate material suction mechanism having both of the above-mentioned two features (1) and (2). And the effect of reducing the risk of plate material falling off is obtained.
[0047]
Further, in the above description, regarding the feature of the above (2), it is only described that the suction hole 23 having a smaller diameter than the inside of the area 22 is provided in the area 21 (excluding the inside of the area 22). 3 and 4 show examples of the structure of the two types of suction holes 23, but the shape of the suction holes 23 is not limited to this example.
[0048]
That is, in the examples of FIGS. 3 and 4, the suction holes 23 have a right circular column shape, but may have a rectangular column shape such as a quadrangular column or a hexagonal column. However, since the amount of air entering from the suction hole 23 is determined mainly by its cross-sectional area, there is no advantage in that the suction hole 23 is formed in a particularly prismatic shape. However, since it can be formed only by making a hole in the drum outer peripheral surface 11a with a drill or the like, it is advantageous in terms of cost.
[0049]
However, when the suction hole 23a as shown in FIG. 4 is drilled, the smaller the diameter of the hole and the deeper the hole, the longer the elongated drill is required, so that the risk of breakage of the drill increases. . In order to avoid such a danger, for example, as shown in FIG. 5, with respect to the suction hole 23a provided in the area 21 (excluding the area 22), the hole is bisected at a predetermined depth, and The diameter of the right cylindrical portion 23aA closer to 11a is large (for example, approximately equal to the width of the suction groove 24), and the diameter of the right cylindrical portion 23aB near the inner peripheral surface opposite to the outer peripheral surface 11a is small (for example, (Approximately half the width).
[0050]
In order to form a hole having a step as shown in FIG. 5, a hole having a large diameter is first drilled from the outer peripheral surface to a predetermined depth, and then a small diameter drill is formed from the bottom surface to the inner peripheral surface of the hole. It is sufficient to make a hole further. In this case, although the portion having a smaller diameter is shorter than the suction hole 23a in FIG. 4, the amount of air entering from the suction hole 23 is not so different. This is because the amount of air entering from the suction holes 23 is mainly determined by the minimum cross-sectional area.
[0051]
As described above, according to the present embodiment, when the plate 2 having a size smaller than the maximum is used, air enters the drum 1 through the suction holes 23 (leakage holes) not covered by the plate 2, but the air leaks. Since the number of holes is smaller than before and the diameter of the leak holes is smaller than before, the amount of air entering can be greatly reduced. Therefore, even if the suction force of the blower 4 is the same as the conventional one, the pressure difference between the inside and the outside of the drum 1 is kept large, and the strength of the plate material 2 adsorbed on the outer peripheral surface 1a of the drum becomes higher than before. As a result, when the drum 1 is rotated at a high speed, the risk of the plate 2 falling off from the outer peripheral surface 1a of the drum is significantly reduced.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of a cylindrical outer surface scanning type image recording apparatus using a plate material suction mechanism according to an embodiment of the present invention.
FIG. 2 is a diagram showing an outer peripheral surface 11a of a drum 11 shown in FIG.
FIG. 3 is a structural example (top view and cross-sectional view) of a suction hole 23 provided in an area 21 (excluding an area 22) shown in FIG. 2, that is, a suction hole 23 that can be a leakage hole.
FIG. 4 is a structural example (top and sectional views) of a suction hole 23 provided in an area 22 shown in FIG. 2;
FIG. 5 is another structural example (top view and sectional view) of a suction hole 23 provided in an area 21 (excluding an area 22) shown in FIG.
FIG. 6 is a diagram showing an overall configuration of a conventional cylindrical outer surface scanning type image recording apparatus.
FIG. 7 is a developed view of an outer peripheral surface 1a of the drum shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Drum 11a ... Outer peripheral surface 2 ... Plate material 3 ... Main scanning motor 4 ... Blower 5 ... Drawing part 7 ... Sub-scanning motor 8 ... Sub-scanning feed screw 12 ... Image data 21 ... Area 22 around which a plate material of the maximum size is wound ... Area 23 around which the plate material of the minimum size is wound 23 ... Suction holes 23a ... Suction holes 23aA and 23aB that can be leakage holes

Claims (8)

A plate material suction mechanism used for a cylindrical outer surface scanning type image recording device that records a two-dimensional image on a plate material wound around a drum, and that causes the plate material to be suction-fixed on an outer peripheral surface of the drum,
The inside of the drum is hollow, a cylindrical drum having a plurality of suction holes formed on the outer peripheral surface thereof, and air discharging means for sucking air from the inside of the drum and discharging the air to the outside,
On the outer peripheral surface of the drum,
A first area around which the smallest plate is wound;
A second area that includes the first area and around which a plate material of the maximum size is wound;
A plate material suction mechanism, wherein a suction hole having a smaller diameter is provided in the second area excluding the first area as compared with the first area. The plate material suction mechanism according to claim 1, wherein each of the suction holes is formed in a right circular column shape. A suction hole provided in the second area excluding the first area has a first right cylindrical portion near the outer peripheral surface of the drum and an inner peripheral surface opposite to the outer peripheral surface. And a second right circular column portion at
The first right cylindrical portion has the same diameter as the suction hole provided in the first area, and only the second right cylindrical portion is provided in the first area. The plate material suction mechanism according to claim 2, wherein the plate material suction mechanism has a smaller diameter than the suction hole. 2. The printing plate according to claim 1, wherein suction holes are provided in the second area excluding the first area at a lower density than in the first area. 3. Suction mechanism. The plate suction mechanism according to claim 1, wherein a suction groove passing through each of the suction holes is formed on an outer peripheral surface of the drum. A plate material suction mechanism used for a cylindrical outer surface scanning type image recording device that records a two-dimensional image on a plate material wound around a drum, and that causes the plate material to be suction-fixed on an outer peripheral surface of the drum,
The inside of the drum is hollow, a cylindrical drum having a plurality of suction holes formed on the outer peripheral surface thereof, and air discharging means for sucking air from the inside of the drum and discharging the air to the outside,
On the outer peripheral surface of the drum,
A first area around which the smallest plate is wound;
A second area that includes the first area and around which a plate material of the maximum size is wound;
A plate material suction mechanism, wherein suction holes are provided in the second area excluding the first area at a lower density than in the first area. While rotating the cylindrical drum, the drawing unit that irradiates the drum with laser light modulated by the image signal is moved in parallel with the rotation axis of the drum, so that a two-dimensional image is formed on the plate material wound around the drum. A cylindrical outer surface scanning type image recording device for recording
A cylindrical drum having a hollow inside and a plurality of suction holes formed on an outer peripheral surface thereof,
A first drive unit for rotating the drum,
Air discharging means for sucking air from the inside of the drum and discharging the air to the outside,
A drawing unit that irradiates the drum with laser light modulated by an image signal, and a second drive unit that moves the drawing unit parallel to a rotation axis of the drum,
On the outer peripheral surface of the drum,
A first area around which the smallest plate is wound;
A second area that includes the first area and around which a plate material of the maximum size is wound;
An image recording apparatus, characterized in that a suction hole having a smaller diameter is provided in the second area excluding the first area as compared with the first area. While rotating the cylindrical drum, the drawing unit that irradiates the drum with laser light modulated by the image signal is moved in parallel with the rotation axis of the drum, so that a two-dimensional image is formed on the plate material wound around the drum. A cylindrical outer surface scanning type image recording device for recording
A cylindrical drum having a hollow inside and a plurality of suction holes formed on an outer peripheral surface thereof,
A first drive unit for rotating the drum,
Air discharging means for sucking air from the inside of the drum and discharging the air to the outside,
A drawing unit that irradiates the drum with laser light modulated by an image signal, and a second drive unit that moves the drawing unit parallel to a rotation axis of the drum,
On the outer peripheral surface of the drum,
A first area around which the smallest plate is wound;
A second area that includes the first area and around which a plate material of the maximum size is wound;
An image recording apparatus, characterized in that suction holes are provided in the second area excluding the first area at a lower density than in the first area.

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