JPH0743498B2 - Sensitive material holding drum of scanning type copying camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention is provided in a recording unit of a copying camera such as a plate making camera, and is configured to rotate in synchronization with scanning movement of a document holding frame. The present invention relates to a sensitive material holding drum.

<< Prior Art >> As a photosensitive material holding drum of this type, conventionally used are those used for holding recording paper in general copying machines, and are roughly classified into a vacuum suction type and a fixing type. Is
For example, Japanese Examined Patent Publication No. Sho 56-24270 (hereinafter referred to as Conventional Example 1).
Alternatively, the one disclosed in JP-A-59-171676 (hereinafter referred to as Conventional Example 2) is known.

That is, in Conventional Example 1, the holding means provided on the drum is configured to suck and hold the front end portion of the sheet material from the back by the suction mechanism, and in Conventional Example 2, the holding means is clamped by the sheet mechanism. It is configured to clamp and hold the tip of the.

Further, JP-A-60-179730 (hereinafter referred to as Conventional Example 3)
Discloses a photosensitive material holding device provided with a charging means for electrostatically attracting a photosensitive material.

<< Problems to be Solved by the Invention >> In both the conventional example 1 and the conventional example 2, the photosensitive material holding structure is complicated and the cost is high. Moreover, since the drum itself is made of heavy metal such as iron, the inertia moment is large, and a drive motor having a large drive output is required to smoothly achieve the synchronous rotation control with the document holding frame.

On the other hand, Conventional Example 3 has a simple photosensitive material holding structure, but when it is applied to the photosensitive material holding device as it is, when a so-called backing sensitive material is used, light transmitted through the sensitive material causes halation.

The present invention has been made in view of such circumstances. To simplify the structure for holding sensitive material, b. To reduce the rotational moment of inertia of the drum to miniaturize the drive source, c. It is a technical subject to prevent the above halation when using a sensitive material for back-side shooting.

<< Means for Solving Problems >> The present invention is configured as follows to solve the above problems.

That is, a photosensitive material holding drum of a traveling type copying camera provided in a recording unit of a copying camera so as to rotate in synchronization with traveling movement of a document holding frame, the drum being formed of a conductive light metal material, The present invention is characterized in that the drum surface is coated with a black coating made of a dielectric substance, and that the drum surface has a charging means for charging an electrostatic charge for adsorbing and holding a photosensitive material.

<< Operation >> In the present invention, the photosensitive material is electrostatically attracted to the photosensitive material holding drum by the charging means. In addition, the drum formed of a light metal material has a small rotational moment of inertia, which facilitates rotational drive control. In addition, since the black coating made of a dielectric substance deposited on the surface of the drum does not reflect the light transmitted through the photosensitive material when the photosensitive material is used for backside photography, the halation does not occur.

<Embodiment> FIG. 1 is a sectional view of a main part of a photosensitive material holding drum according to the present invention, and FIG. 2 is a schematic view of a scanning copying camera.

This scanning type copying camera is composed of a document holding frame 1 which is horizontally movable in the direction of arrow A, an illuminating lamp 2 arranged above the document holding frame 1, a plurality of mirrors 3 and an imaging lens 4. A drum 7 provided in the image optical system and the recording unit 5 rotates in synchronization with the traveling movement of the document holding frame 1 and sucks and holds the photosensitive material 6 on its outer peripheral surface as a basic configuration.

In FIG. 2, reference numeral 20 is a roll film cassette, 32 is a cutter for cutting the film 9 fed from the cassette 20 to a required length, and 22 is the drum 9 for the film 9.
A belt conveyer for conveying the film toward 23, 23 is provided so as to be able to roll in the direction of arrow B, and is a traveling path of the document holding frame 1.
A guide member that guides the film 9 from the conveyor 22 toward the drum 7 so as to traverse 18; 24 is a feed roller that feeds the film 9 toward the drum 7; 25 and 26 are film pressing rollers; and 27 is an exposed film. The drum 7
A separating roller for peeling from the film, 28 is a belt conveyor for discharging the film, and 29 is a film collecting box.

The photosensitive material holding drum 7 is made of a conductive light metal material such as aluminum material, and has a small rotational moment of inertia, which facilitates rotational drive control. Further, the drum surface is provided with a charging means 10 (FIG. 1) for charging an electrostatic charge.

The charging means 10 is a DC voltage applying power source 11, a switch 12,
It is composed of conductive connectors 13 and 14 for connecting the power source 11 to the drum 7 via the support shaft 8.

As the DC voltage applying power supply 11, the potential of the drum surface is 1 to
It is desirable to keep it at about 3KV. For example, when a polyester base film is used as the photosensitive material, the surface potential of the drum of 1 to 2 KV is sufficient for adsorption and holding due to electrostatic charge. Even when the roll film is strongly wound, a surface potential of 2 to 3 KV is sufficient for adsorption and retention. However, if the surface potential becomes higher than that, fogging due to electric discharge occurs when the film 9 is peeled from the drum 7, or dust is attracted and adhered to the surface of the film 9, which causes countless numbers on the exposed and developed film original plate. This will cause pinholes (white areas).

A coating 7a made of a dielectric material is formed on the surface of the drum 7 so as not to leak even if a worker comes into contact with the device during maintenance work of the device. However, when the charger 16 shown by the broken line in FIG. 2 is used as the charging means as described later, such a dielectric film 7a is indispensable. Further, the dielectric film 7a is made black so that the light transmitted through the film 9 is not reflected again on the drum surface. Even when using a so-called backside film, halation does not occur because the transmitted light of the film is not reflected.

Reference numeral 30 shown in FIG. 1 denotes an insulating resin flange provided on the bearing portion.

In the above embodiment, the charging means is electrically connected to the drum via the support shaft by the direct current voltage applying power source. The charger 16 may be arranged in close proximity.

In the case of using the charger 16, the drum 7 is charged while rotating, whereas in the case of using the charging means 10, the charging is not necessary, which is convenient for controlling the rotational position of the drum 7.
That is, when the film is wound, the drum 7 is adjusted so that the leading end thereof matches the drum rotation reference position at the start of exposure.
This is because the charging can be performed in a state of being stopped and waiting.

The operation of the copying camera will be briefly described below.

First, a document is set in the document holding frame 1 in advance.
Next, when a photosensitive material mounting key (not shown) is started, the switch 12 of the charging means 10 is turned on, and electrostatic charges are charged on the drum surface. On the other hand, the film 9 is unwound from the cassette 20 and cut into a required length by the cutter 21. The cut film 9 is sent through the conveyor 22, the guide member 23, and the feed roller 24 and wound around the drum 7.

Next, the guide member 23 blocking the traveling path 18 of the document holding frame 1 rolls over in the direction of arrow B to open the traveling path 18, and the document holding frame 1 once enters the inner part of the traveling path 18. This entry position serves as a reference position for starting exposure.

Then, the illumination lamp 2 is turned on at the same time when the traveling to the exit side (the left side of the paper) is started, and the drum 7 rotates in synchronization with the traveling movement of the document holding frame 1. When the document holding frame 1 has finished withdrawing, the illumination lamp 2 is turned off, and the switch 12 of the charging means 10 is turned off. During this time, the exposed film 9 is peeled from the drum 7 by the peeling roller 27 from the starting end side, and the conveyor 28
After that, the film is recovered in the film recovery box 29.

The above photographing cycle is repeated in the same manner.

<Effects of the Invention> As is clear from the above description, since the present invention is configured to attract and hold the photosensitive material to the drum by the electrostatic attraction method, compared to the conventional vacuum attraction method and fixture method. The structure can be simplified and the cost can be reduced.

Further, since the drum is made of a light metal material, the rotational moment of inertia becomes small and the rotational drive control becomes easy.
As a result, it is possible to reduce the size of the drive source and thus reduce the cost.

Moreover, since a black coating made of a dielectric substance was applied to the surface of the drum, when using a photo sensitive material for backside photography, it is necessary to prevent reflection of light transmitted through the photo sensitive material to prevent halation. You can

Especially when the charging means is constructed by conductively connecting a DC voltage applying power supply to the drum via a support shaft, it is not necessary to rotate the drum to charge the surface of the drum with electrostatic charges, so that the rotation position of the drum is controlled. It is convenient.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a photosensitive material holding drum according to the present invention, and FIG. 2 is a schematic view of a scanning type copying camera. 1 ... Original holding frame, 5 ... Recording part, 7 ... Sensitive material holding drum, 8 ... Spindle, 10 ... Charging means, 11 ... DC voltage applying power supply, 13/14 ... Conductive connector, 16 ... Charger.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuyuki Oka 1 480, Takamiya-cho, Hikone City, Shiga Prefecture Dai Nippon Screen Mfg. Co., Ltd. Hikone District Office (56) References JP-A-61-277474 (JP, A) JP 60-179730 (JP, A) JP 45-10322 (JP, Y1)

Claims (2)

[Claims] 1. A photosensitive material holding drum of a scanning type copying camera, which is provided in a recording portion of a copying camera so as to rotate in synchronism with the traveling movement of a document holding frame, the drum being made of a conductive light metal material. A scanning type copying machine, which is formed by depositing a black coating made of a dielectric substance on the surface of a drum, and has a charging means for charging an electrostatic charge for adsorbing and holding a photosensitive material on the surface of the drum. Sensitive material holding drum for the camera. 2. The photosensitive material holding drum of a scanning type copying camera according to claim 1, wherein said charging means is constituted by conductively connecting a DC voltage applying power source to the drum via a support shaft.