JP2669302B2 - Plate making machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate making machine for producing a master which is an original plate for printing, and more particularly to a structure of an exposure stage for exposing a document image on the surface of the supplied master.

[0002]

2. Description of the Related Art As is well known, in a general plate making machine, a master supplied to the surface of an exposure stage is stopped while maintaining a flat state, and an image of an original is exposed on the surface of the master. The stop position of the master on the surface of the exposure stage needs to be accurate because it is related to the position accuracy.

On the other hand, in an exposure stage of a conventional plate making machine, a master sensor capable of sensing the leading end of the master facing a moving path of the master is provided. The stop position of the master is obtained by stopping the feed belt.

[0004]

However, in such a structure of the exposure stage, the master sensor is insensitive because the exposed portion feed belt has inertia and the frictional resistance of the exposed portion feed belt has individual differences. There was a difference in the time from when the master stopped until it was stopped, and it was impossible to stop the master in the correct position. Furthermore, even if the master had a bend, the bend could not be corrected. Of course, if the master is not stopped at the correct position,
Individual differences occur in the exposure position of the original image with respect to the master,
There was a problem that the subsequent process as a printing original plate was troublesome. An object of the present invention is to obtain a plate making machine capable of stopping the master at a predetermined accurate exposure stage position in view of the problem of the stationary position of the master on the conventional exposure stage as described above.

[0005]

In order to achieve this object, according to the present invention, a master supplied from a master supply device is stopped on an exposure stage in a substantially vertical direction arranged in a body housing, and an original is placed on the surface of the master. In a plate making machine that exposes an image, the vacuum pressure of the vacuum box is released when the tip of the master is sensed on the exposure stage, which is composed of a vacuum box and an endless exposure section feed belt located in the vacuum box. The present invention proposes a plate making machine provided with a master sensor and a master stopper which is projected below the constant-exposure-section feed belt and retracts outside the moving range of the master after the master has been exposed.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of a plate making machine according to an embodiment of the present invention will be described below with reference to the drawings. First, referring to FIG. 1, the entire plate-making machine according to the present invention will be described. An original platen 3 having an original platen glass 2 is provided on an upper part of a body housing 1.
An original can be positioned on the surface of the original platen glass 2.

[0007] A master supply device 4 capable of feeding out masters one by one is incorporated in the upper right portion of the body housing 1, and the master fed out from the master supply device 4 is a master feed device 5 and a load electrode. 6, the light is sent to an exposure stage 7 in a substantially vertical direction. The exposure stage 7, which will be described in detail later, is provided with an endless exposure part feed belt 8 and a vacuum box 9 capable of adsorbing the master with a vacuum pressure, and a pair of master stoppers 10A that can project into the moving range of the master under the exposure box 7. , 10B are provided, and the master is stopped with its lower edge abutting against the master stoppers 10A, 10B.

An illumination lamp 11 for illuminating the original on the original platen glass 2 is arranged below the original platen 3, and the original image of the original document positioned on the original platen glass 2 is exposed by the taking lens 12 and the mirror 13 to the exposure stage 7. Will be imaged on the surface of the master that is stationary on the surface of the master.

The master whose latent image is formed on the exposure stage 7 is the developing device 1 below the machine housing 1.
After passing through the developing device 14, the image is developed, dried by a drying device 15 following the developing device 14, and then discharged to a discharge tray 16 at a lower left portion of the body housing 1.

2 and 3 show the details of the exposure stage 7. The exposure stage 7 is slightly tilted with respect to the vertical plane as shown in FIG. 2, and is driven by a driven roller 17 which opposes in the vertical direction. It is provided with four endless exposure section feed belts 8 which are stretched between rollers 18. That is, the surface of the exposure section feed belt 8 is preferably subjected to a smooth surface treatment in order to reduce the frictional resistance with the master, but the entire exposure section feed belt 8 is provided with a pair of blowers 19A, 19B on both sides.
Is housed in a fixed vacuum box 9 and a large number of small holes 20 are formed on the surface of the exposure section feed belt 8. Therefore, the exposure section feed belt 8 is exposed through these small holes 20.
The master is adsorbed to the surface of the substrate by vacuum pressure.

A master sensor 21 composed of a photosensor is located at a position near the lower part of the exposure stage 7, and the master sensor 21 senses the tip of the master. The sensing signal of the master sensor 21 is used as a control signal for the blowers 19A and 19B described above, as will be apparent from the following.

Further, below the exposure stage 7,
A pair of horizontally opposed master stoppers 10A, 10B that receive the lower edge of the master are arranged, and these master stoppers 10A, 10B are always in a protruding state within the moving range of the master. To control these master stoppers 10A and 10B, as shown in FIG. 2, an electromagnetic solenoid 22 is fixed to the back of the vacuum box 9, and a connecting link 23 of the electromagnetic solenoid 22 is pivoted at a middle portion by a fulcrum pin 24. One end of the supported bell crank 25 is attached to the bell crank 25.
The bases of the master stoppers 10A and 10B are coupled to the other end of the.

Next, the operation of the plate making machine described above will be described with reference to the flow charts of FIGS. 4 and 5. FIG. 4 is a flow when the size of the master fed from the master supply device 4 is relatively small. . That is, in the case of a small size master,
When the print start button is pressed by the operator, both the belt drive motor and the blower motors A and B of the blowers 19A and 19B are turned ON, the exposure section feed belt 8 starts rotating, and a vacuum pressure is applied to the small holes 20 ( Step S ₁ ). Next, when the master fed from the master supply device 4 is sent to the exposure stage 7 by the master feeding device 5, the master is adsorbed on the surface of the exposure section feed belt 8 and is lowered along the exposure stage 7.
When the tip portion of the master is sensed by the master sensor 21 (Step S _2), both the blower motor A, B is stopped (Step S _3). Therefore, the vacuum pressure acting on the master from the small holes 20 is weakened, so that the master is weakly sucked and conveyed to the surface of the exposure unit feed belt 8 slightly inclined from the vertical plane, and the lower edge of the master is projected. Locked by master stoppers 10A and 10B. At this time, if the master is not parallel to the master stoppers 10A and 10B, since the exposure unit feed belt 8 is rotating after being locked by one of the master stoppers 10A and 10B, the master bends. Will be forced (step S ₄
). Next, stops exposed portion feed belt 8 by the belt driving motor immediately (step S _5), the blower motor A, B are adsorbed master strongly to ON by the surface of the exposed portion feed belt 8 again (step S ₆₎ .

Next, waiting for the stop of the exposure section feed belt 8 (step S ₇ ), the master stoppers 10 A and 10 B, which have received the lower edge of the master, are retracted by the excitation of the electromagnetic solenoid 22 (step S ₈ ), and the illumination is performed. The lamp 11 is turned on (step S ₉ ), the master exposure time by the taking lens 12 is awaited (step S ₁₀ ), and the illumination lamp 11 is turned off (step S ₁₁ ).
After waiting one full off (step S _12), the belt drive motor is started again. Then, after waiting for the master of the discharge from the exposure stage 7 (step S _13), the exposure unit feed belt 8 is stopped by the belt drive motor, the master stopper 10A, 10 electromagnetic solenoid 22 is demagnetized
With B is returned to the protruded state, a blower motor A, the B stops, the exposure stage 7 returns to the initial state (step S _14).

FIG. 5 shows a case where the size of the master fed from the master supply device 4 is large. When the print start button is pressed by the operator, one of the belt drive motor and one of the blowers 19A and 19B is used. blower motor only is turned oN, the exposure unit feed belt 8 is weak vacuum pressure starts to rotate and the small hole 20 is acting (step S _15). The reason for this is that if a master with a large size is strongly attracted to the surface of the exposure section feed belt 8, the master with a large area will be transferred to the master stopper 10A,
This is because the master's bend cannot be corrected when locked at 10B. Next, the master fed from the master supply device 4 is transferred to the exposure stage 7 by the master feeding device 5.
When sent to, but a master to the surface of the exposed portion feed belt 8 is lowered along the exposure stage 7 is adsorbed, when the tip portion of the master is sensed by the master sensor 21 (step S _16), previously blower motor a has fired is stopped (step S _17). Therefore, the vacuum pressure acting on the master from the small hole 20 becomes weaker.
The master is weakly sucked and conveyed by the surface of the exposure section feed belt 8 slightly inclined from the vertical surface, and the lower edge thereof is locked by the protruding master stoppers 10A, 10B. If the master is not parallel to the master stoppers 10A and 10B, either of the master stoppers 10A or 10B
Since the exposure section feed belt 8 is rotating after being locked at
Bending of the master will be forced (step S
₁₈ ). Then, the belt drive motor immediately stops the exposure section feed belt 8 (step S ₁₉ ), both blower motors A and B are turned on, and the master is strongly attracted to the surface of the exposure section feed belt 8 (step S ₂₀ ). .

Next, waits for the stop of the exposure unit feed belt 8 (step S _21), the master stopper 10A which had received the lower edge of the master, 10B are retreated by the excitation of the electromagnetic solenoid 22 (step S _22), lighting lamp 11 is turned on (step S _23), after waiting for the master of the exposure time by the imaging lens 12 (step S _24), the illumination lamp 1
When 1 is turned off and only the blower motor B is stopped, the suction force to the master is weakened (step S ₂₅ ),
After the lighting lamp 11 is completely turned off (step S
₂₆ ), the belt drive motor is started again (step S)
₂₇ ). After this, after waiting for the master to be discharged from the exposure stage 7 (step S ₂₈ ), the belt drive motor is turned off to stop the exposure section feed belt 8 and the electromagnetic solenoid 2
2 is demagnetized master stopper 10A, with 10B is returned to the protruding state by stopping the blower motor A, the exposure stage 7 returns to the initial state (step S _29).

In the illustrated embodiment, the master supply device 4 for supplying cut paper is illustrated, but a roll paper supply device for cutting and supplying a master roll in accordance with an operator's instruction is used instead of the master supply device 4. May be. Further, for the master size detection, a sensor (not shown) is arranged on the paper feeding table, and the size of the master is confirmed by this.

[0018]

As is apparent from the above description, according to the present invention, a master stopper for receiving the lower edge of the master is provided at the lower part of the exposure section feeding belt, and when the tip of the master is detected by the master sensor. In addition, since the master can be reliably stopped at the position determined by the master stopper by controlling the vacuum pressure of the vacuum box and the movement of the exposure section feed belt, and the inclination of the master is corrected, the exposure position of the original image is always Since it is constant, the value of the master as a printing original plate is improved.

[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 side sectional view of an exposure stage of the plate making machine.

FIG. 3 is a partially cutaway front view of the exposure stage.

FIG. 4 is a control flow diagram of the same exposure stage when creating a small size master.

FIG. 5 is a control flow of the exposure stage when a large size master is created.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Airframe housing 4 Master supply device 7 Exposure stage 8 Exposure part feed belt 9 Vacuum box 10 Master stopper 21 Master sensor

Claims (1)

(57) [Claims] 1. In a plate making machine for exposing a document image on the surface of the master by stopping a master supplied from a master supply device on an exposure stage arranged in a housing of the machine in a substantially vertical direction, a vacuum box and a vacuum box The exposure stage consisting of an endless exposure unit feed belt positioned at a master sensor that releases the vacuum pressure of the vacuum box when the tip of the master is sensed, and is constantly projected at the lower part of the exposure unit feed belt. A plate making machine comprising: a master stopper that retreats outside the moving range of the master after the master is exposed.