JPH0671997A - Rotary transfer printer - Google Patents

Abstract

PURPOSE:To reduce the rigidity at both ends of a printing drum of metal mesh sheet. CONSTITUTION:A printing drum consisting of a metal mesh sheet 36 has holes 40 formed in the non-printed area. The holes 40 are filled with a resin material 41. Consequently, the cylindrical printing drum, when pressed by a press roller, is no longer deformed to the shape of a barrel with a contracted middle part. Thus the cylindrical drum is adequately flexible up to both ends, allowing a printable area to be used efficiently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary copying machine, and more particularly to a rotary copying machine in which a sheet-like metal mesh is formed into a cylindrical shape to form a printing drum.

[0002]

2. Description of the Related Art Generally, in a rotary transcription printing machine, at least a surface of a rubber press roller is in contact with a printing drum formed of a sheet-shaped metal mesh, and the printing drum at the contacting position is in contact with the printing drum. An ink application roller is in contact with the inner peripheral surface. When the printing drum, press roller, and ink application roller are in contact with each other, the pressing force of the press roller acting on the printing drum escapes to both ends, and the center of the printing drum is dented and deformed into a drum shape. To do. That is, the press roller is also deformed such that both ends thereof are depressed and the central portion bulges, so that only the central portion of the printing drum can be pressed. When this tendency becomes remarkable, good printing can be performed only in the central portion of the printing drum. Therefore, in order to perform good printing on printing paper of a predetermined size, it is necessary to provide a printing drum that is considerably wider than the printing paper. Then, there is a problem that the size of the apparatus is forced to be larger than the size of the paper.

In order to solve the above-mentioned problems, conventionally, the metal mesh sheet forming the printing drum is made thinner at both end portions which are non-printing areas than at the central portion, and the rigidity of the portions is relatively set. Japanese Patent Laid-Open No. Hei 4
No. 105982 is disclosed. Actually, an extra etching process is performed to make both ends thin, but there is a processing inconvenience such as a hole being formed unless the etching time is controlled with high accuracy.

[0004]

SUMMARY OF THE INVENTION The present invention has been devised in order to effectively solve the above-mentioned conventional technical problems in view of the problems mentioned above. Therefore, an object of the present invention is to provide a rotary transcription printing machine provided with a printing drum which can be easily processed when the rigidity of both ends of the printing drum in which a metal mesh sheet is formed in a cylindrical shape is lowered.

[0005]

The rotary transcription printing press according to the present invention has the following structure in order to solve the problems of the prior art as described above and to achieve the object. That is, a sheet-shaped metal mesh having a large number of small holes in a print area is formed into a cylindrical shape, and a rotary press provided with a print drum having non-print areas at both ends of the print area. In the copying printer, the non-printing area of the printing drum has a plurality of holes, and the holes are closed by a filled soft resin material. The hole is preferably formed by electroforming and has a step portion in its cross-sectional shape. Further, the holes can be formed by etching.

[0006]

In the rotary transcription printing machine according to the present invention, the plurality of holes formed in the non-printing area of the sheet-shaped metal mesh lowers the rigidity of both end portions of the cylindrical drum. Since these holes are filled with the soft resin material and closed, the ink does not flow out to the non-printed area. Also,
Since the resin material to be filled is not a hard material but a soft material, the rigidity of both end portions of the drum lowered by the opening is not increased more than necessary. Therefore, it is possible to cope with an increase in the size of printing paper without making the printing drum unnecessarily large.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rotary transcription printing machine according to an embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an explanatory diagram showing a schematic configuration of a rotary copying machine of the present embodiment. In the figure, 1 is a printing drum, 2 is a press roller, 3 is a base paper discharging mechanism part, 4 is a base paper roll, 5 is a thermal head for plate making, 6 is a plate making finished paper, 8 is a press roller driving mechanism part,
Reference numerals 9 ₁ , 9 ₂ , and 9 ₃ denote printing paper trays, 10 denotes a paper feed mechanism unit, 11 denotes a paper discharge receiving unit, and 12 denotes a document reading unit.

On the printing drum 1, there are provided a base paper clamper 13 for gripping the leading end of the base paper supplied with the base paper prepared by the thermal head 5, and a leading end of the base paper discharged after the desired printing is completed. A base paper flip-up lever 14 to be introduced into the base paper discharge mechanism section 3 is attached. Although not shown in FIG. 1, the printing drum 1 has a built-in ink application mechanism, and the drum 1 on which the base paper is mounted has ink between the surface of the drum 1 and the base paper. Is supplied. The plate making is performed by the document reading unit 12
The thermal head 5 is supplied with electric power based on the image signal scanned in to form a plate of the original image on the thermosensitive base paper. Note that the plate-making base paper 6 stands by in the state shown in the figure until the used base paper on the printing drum 1 for which printing has been completed is discharged from the drum 1.

The press roller 2 has the same diameter as that of the printing drum 1, and has a driving mechanism section 8 as an independent driving system separate from the driving system (not shown) of the printing drum 1. It is configured to rotate in synchronization. In addition, the press roller 2 is provided with a relief recess 1 at a position corresponding to the base paper clamper 13 and the base paper flip-up lever 14 on the drum 1.
5 is formed so as not to interfere with the clamper 13 and the lever 14 when the roller 2 rotates in synchronization with the drum 1. Inside the concave portion 15, a locking claw 16 that locks the printing paper fed from the paper feeding mechanism 10 toward the roller 2 at its tip is provided.

The printing paper consists of three printing paper trays 9 ₁ ,
It is divided into 9 ₂ and 9 ₃ and is stocked for each paper size.
The printing paper of the selected desired size is directed from each paper tray to the press roller 2 through the paper feeding mechanism unit 10.
It is sent out one by one. Since the press roller 2 rotates while the leading end of the printing paper is locked by the locking claw 16, the printing paper is sequentially sandwiched between the printing drum 1 and the press roller 2 for printing. The printed paper is held on the peripheral surface of the press roller 2 without sticking to the print drum 1 because the leading end of the printed paper remains locked by the locking claw 16 and rotates. When the sheet reaches the front of the sheet discharge roller 17, the locking claw 16 is unlocked, so that the sheet is released from the locking claw 16 and discharged to the sheet discharge receiving portion 11 via the discharge roller 17.

Although not shown in FIG. 1, the printing drum 1 has a built-in ink application mechanism, and the drum 1 on which the base paper is mounted has the surface of the drum 1 and the base paper from the inside. Ink is supplied in the meantime. Print drum 1
The ink applying mechanism will be described with reference to FIG. The printing drum 1 is made of a flexible sheet-shaped metal mesh in a cylindrical shape so that the ink supplied from the inside is sufficiently absorbed, and has sufficient flexibility. It is the transfer roller 18 of the ink application mechanism that receives the pressure of the press roller 2 substantially at the contact portion between the print drum 1 and the press roller 2. The transfer roller 18 is a roller made of rubber on the surface, which is inscribed in the printing drum 1 and supplies ink to the printing drum 1 while rotating in the same direction and at the same peripheral speed. The ink is first stored in the ink tank 22 (see FIG. 3).
The ink reservoir 21 is formed between the ink roller 19 and the squeegee roller 20 in response to the supply from the ink. The ink roller 19 and the squeegee roller 20 are both rollers made of metal and are in contact with each other. A fine groove is formed on the surface of the squeegee roller 20 with high dimensional accuracy, and the ink supply amount is accurately controlled by the gap formed between both rollers by this groove. Further, the ink moves from the ink roller 19 to the transfer roller 18, but both rollers 18, 1
Since 9 are in contact with each other while rotating in the same direction,
At the contact points, the outer peripheral surfaces of the ink rollers advance in a direction in which they face each other. Therefore, the ink on the outer peripheral surfaces of the ink rollers 19 moves to the transfer roller 18 by about 100%. Moreover, since the outer peripheral surface of the transfer roller 18 is formed of rubber, the ink is sufficiently compatible with the transfer roller 18. In this embodiment, the surface of the transfer roller 18 is made of rubber, but even a relatively hard synthetic resin can provide a certain degree of ink affinity, or even if it is made of metal, it can be made of a conventional metal roller. It is practical because it can be expected to have an ink affinity equivalent to. In particular, in the case of a metal roller, there is no fear that the roller will contain ink and swell or deteriorate, and the durability is excellent.

As described above, since the transfer roller 18 is inscribed in the print drum 1 and rotates in the same direction at the same peripheral speed, only the required amount of ink is transferred to the print drum 1 and the excess ink is transferred. While being attached to the surface of the roller 18, it is transported over the contact point between the transfer roller 18 and the printing drum 1. The surplus ink on the transfer roller 18 reaches the contact point with the ink roller 19 again, where it is almost completely recovered by the ink roller 19 and returned to the ink reservoir 21. In this way, no ink pool is formed on the back surface of the print drum 1, and a good ink supply state to the print drum 1 is always obtained.

By changing the peripheral speed ratio of the ink roller 19 to the transfer roller 18, the amount of ink transferred to the transfer roller 18 can be variably adjusted. For example, the ink roller 19
If the speed is reduced by half, the amount of ink transferred to the transfer roller 18 is also reduced by half. Furthermore, since the surface of the transfer roller 18 is rubber, the pressure of the press roller 2 can reasonably and appropriately act on the paper on the printing drum 1 to perform good printing.

In the above-described embodiment, the ink applying mechanism is applied to the single cylinder type printing machine.
Needless to say, it can be applied to a twin-cylinder type or a double-cylinder type printing machine as shown in FIG. In FIG. 7, 51 is a screen, 52 is a drum around which the screen 51 is stretched,
53 is a press roller. The ink application mechanism is provided in the screen 51 between the drums 52 and 52.
The screen 51 is sandwiched between the transfer roller 54 and the press roller 53, and is rotated by the contact with both rollers 53, 54. The screen 51 and the peripheral surface of the transfer roller 54 advance in the same direction at the same speed. In the figure, 55 is an ink roller, 56 is a squeegee roller, and 57 is an ink reservoir.

As will be described in detail later, the printing drum 1
Is configured to be movable in the axial direction with respect to the press roller 2, but the transfer roller 18 in the printing drum 1 is axially supported so as not to move in the axial direction with respect to the press roller 2. That is, since the relative axial positional relationship between the transfer roller 18 and the press roller 2 is fixed, the pressure acting on the transfer roller 18 from the press roller 2 is always constant even if the print drum 1 moves. .

Since the surface of the transfer roller 18 is made of rubber and the ink roller 19 rotates in the direction opposite to the surface of the transfer roller 18, when ink is present between the rollers 18 and 19, the ink acts as a lubricant and both rollers are in contact with each other. Although rotation of 18 and 19 is allowed, a large frictional force is generated when the transfer roller 18 is dry. In such a state, both rollers 18, 1
When 9 rotates, the rubber surface of the transfer roller 18 may be damaged by friction. Therefore, it is preferable to release the contact between both rollers 18 and 19 when the transfer roller 18 is dry. Specifically, for example, the transfer roller 18
Alternatively, one of the shafts of the ink roller 19 may be spring-biased toward the contact state so that the roller can escape when an excessive frictional force acts. Further, when the ink roller 19 is configured to escape, it is preferable not to change the relationship between the ink roller 19 and the squeegee roller 20, so that the ink roller 19 and the squeegee roller 20 are integrally escaped. Is preferred.

FIGS. 3 and 4 are partial cross-sectional views showing the respective supporting states of the printing drum 1 and the transfer roller 18 provided therein, and FIG. 3 is a state in which the printing drum 1 is located at the right end. Reference numeral 4 indicates a state in which the print drum 1 is located at the left end. Reference numeral 23 in the drawing denotes a main body frame, and a drive shaft 24 for rotating the printing drum 1 is rotatably supported on the main body frame 23. Drive shaft 2
A drive gear 25 is fixedly attached to the inner end of 4. on the other hand,
The center shaft 26, which is the rotation axis of the print drum 1, is supported so as not to rotate with respect to the main body frame 23, and the print drum 1 is rotatably and slidably mounted on the center shaft 26. The fixed center shaft 26 is provided with an ink supply passage of the ink application mechanism portion, or an electric wire can be inserted therein. Reference numeral 22 in the drawing is an ink tank, and the ink flows from the ink pump 27 through the ink supply pipe 28 into the center shaft 26, and drops an appropriate amount into the ink pool 21 between the squeegee roller 20 and the ink roller 19 described above. Supplied.

At one end of the center shaft 26, there is provided a gear-like spline shaft 29 which is long in the axial direction.
The spline shaft 29 is rotatably mounted via 0 ₁ and 30 _2, and one end of the spline shaft 29 meshes with the drive gear 25.
Further, one boss portion 31 _R of the printing drum 1 is formed with an inner peripheral spline in the shape of an internal gear that meshes with the spline shaft 29. That is, the driving force input to the drive shaft 24 is transmitted to the print drum 1 via the drive gear 25 and the spline shaft 29 to rotate the print drum 1. Further, the engagement between the boss portion 31 _R and the spline shaft 29 is determined by the spline shaft 2
Allows the boss 31 _R to slide in the axial direction with respect to 9. The printing drum 1 is also attached to the other end of the center shaft 26.
The other boss portion 31 _L is mounted rotatably and slidably via a bearing 30 ₃ . That is, the bearing 30
₃ , the inner peripheral portion is slidable in the axial direction with respect to the center shaft 26, and the outer peripheral portion is rotatable. In this way, the printing drum 1 is movable in the axial direction within a predetermined range. The spline shaft 29 also functions as a gear for transmitting the rotational driving force even at one end in the drum 1, and rotationally drives each roller (see FIG. 2) of the ink applying mechanism in the drum 1. It meshes with the gear.

Reference numeral 32 in the drawing denotes a motor for driving the axial movement of the printing drum 1. A worm gear 33 is attached to the output shaft of the motor 32, and a pinion gear (not shown) meshes with the worm gear 33. The shaft of the pinion gear extends in parallel with the center shaft 26 of the printing drum 1, and a male screw is formed on the outer peripheral surface thereof. On the other hand, the bearing 30 ₃ provided between the printing drum 1 and the center shaft 26 has a female screw formed on the inner peripheral portion thereof and is screwed with a male screw of the shaft of the pinion gear. That is, when the motor 32 rotates, the worm gear 33 rotates the pinion gear, and the rotation of the shaft of the pinion gear moves the threadedly coupled bearing 30 ₃ along the center shaft 26. The printing drum 1 moves axially with the bearing 30 ₃ . When the rotation direction of the motor 32 is reversed, the movement direction of the print drum 1 is also reversed. The movement of the printing drum 1 in the axial direction is performed with the depression 15 of the press roller 2 facing the printing drum 1,
That is, if the pressing force of the press roller 2 is applied to the printing drum 1, the driving load is sufficiently small.

The transfer roller 18 of the ink applying mechanism is
Has an axial length dimension sufficient to cover the movement width of the printing drum 1. In the figure, 34 is a lever for pulling out the drum unit from the apparatus main body when the entire drum unit is replaced, and 35 is the ink tank 2
It is a lever for pulling out 2. The drum unit is
The center shaft 26 and the spline shaft 29 are also held by the drum support frame 50. When the drum unit is pulled out from the apparatus main body, the center shaft 26 separates from the main body frame 23 and the spline shaft 29 separates from the drive gear 25. .

As described above, the printing drum 1 is made of a flexible sheet-shaped metal mesh into a cylindrical shape. Generally, a metal sheet having a thickness of about 0.2 mm is formed by electroforming. As shown in FIG. 5, the metal sheet 3
In the non-printed areas 37 at both ends of 6, a large number of holes 40 larger than the small holes 39 formed uniformly in the printed area 38 are formed. By forming the holes 40, the flexibility at both ends of the metal sheet 36 is enhanced. That is, when the press force of the press roller 2 is received, the printing drum 1
Is sufficiently bent to both ends thereof, and substantially the entire original printing area 38 can be effectively used. The holes 40 formed in the non-printed areas 37 at both ends are closed by the resin material 41, and the ink does not leak from the holes 40. Further, the resin material 41 is sufficiently flexible, and the flexibility of both ends of the printing drum 1 is hardly impaired by being filled with the resin material. As shown in FIG. 6, the hole formed by electroforming has a stepped portion 42 in its cross-sectional shape corresponding to the resist layer on the electroformed base material. Therefore, the resin material 41 with which the hole 40 is filled is caught by the step portion 42 and exerts a sufficient coupling force, and does not fall off even if both end portions of the drum 1 are bent. Further, in practice, the resin material 41 may not be filled in each hole 40, but the resin material 41 may be applied and cured over the entire non-printing area 37, so that sufficient bonding force and sufficient flexibility can be obtained. can get. The holes 40 can of course be formed by etching.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a rotary copying printer according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a schematic configuration of a printing drum, an ink applying mechanism section, and a press roller in a rotary transcription printing machine according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a main part of a moving mechanism of the printing drum in the embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a state in which the moving mechanism of FIG. 3 is located at the left end of the printing drum.

FIG. 5 is an explanatory diagram showing mesh shapes of a metal mesh sheet in a printing area and a non-printing area of a printing drum according to an embodiment of the present invention.

6 is a cross-sectional view of the metal mesh sheet of FIG.

FIG. 7 is an explanatory diagram showing a schematic configuration of a screen, an ink application mechanism section, and a press roller in a rotary transcription printing press according to another embodiment of the present invention.

[Explanation of symbols]

1 Printing Drum 2 Press Roller 3 Base Paper Discharging Mechanism Section 4 Base Paper Roll 5 Plate Making Thermal Head 6 Plate Making Base Paper 8 Press Roller Driving Mechanism Section 9 Printing Paper Tray 10 Paper Feeding Mechanism Section 11 Paper Discharge Receiving Section 12 Original Reading Section 13 Base Paper Clamper 14 Base paper flip-up lever 15 Escape recess 16 Locking claw 17 Paper discharge roller 18 Transfer roller 19 Ink roller 20 Squeegee roller 21 Ink pool 22 Ink tank 23 Main frame 24 Printing drum drive shaft 25 Drive gear 26 Center shaft 27 Ink pump 28 Ink supply tube 29 Spline shaft 30 Bearing 31 Boss portion 32 Motor 33 Worm gear 34 Lever 35 Lever 36 Metal sheet 37 Non-printing area 38 Printing area 39 Small hole 40 hole 41 Resin material 42 Step portion 50 Drum support frame Reservoir over arm 51 screen 52 drum 53 press roller 54 transfer roller 55 ink roller 56 squeegee roller 57 ink

Claims (3)

[Claims] 1. A sheet-shaped metal mesh (3) having a large number of small holes (39) in a portion to be a printing area (38).
6) is formed in a cylindrical shape, and a rotary copying machine provided with a printing drum (1) having a non-printing area (37) at both ends of the printing area (38), wherein the printing drum (1) Is a non-printing area (37) having a plurality of holes (40), and the holes (40) are closed by a filled soft resin material (41). . 2. The rotary transcription printing machine according to claim 1, wherein said hole (40) is formed by electroforming and has a step portion (42) in its cross-sectional shape. 3. The rotary transcription printing press according to claim 1, wherein the holes (40) are formed by etching.