FR2530904A1 - OPENING MASK FOR IMAGE EXPLORATION AND RECORDING DEVICES - Google Patents

Abstract

A MASK WITH OPENINGS 22 FOR USE IN THE RECORDING PART OF AN EXPLORATION AND IMAGE RECORDING DEVICE PRESENTS TWO OPENINGS 29, PREFERREDLY IDENTICAL IN THE POINT OF VIEW OF THEIR DIMENSIONS AND SHAPE, WHICH ARE ARRANGED ON THE OPTICAL PATH OF A LUMINOUS BEAM TO IMPRINT A RECORDING MEDIA, THE TWO OPENINGS 29 BEING SPACED AT A DETERMINED DISTANCE L.

Description

Mask with openings for exploration and detection devices

image registration.

  The present invention relates to an ex-

  ploration and recording of images intended to reproduce images on a recording sheet covered with a

  sensitive material by means of image signals obtained in ex-

  photo-electrically plotting original images, and in particular to equipment for exposure to a light beam.

  This kind of exploration and recording device

  trement images is used in practice for example in facsimile machines and color pickers

  or scanners to produce chromatically selected images

  from a color original in the area of

photomechanical processes.

  A device for exploring and recording i

  mages like this is described below As shown in Figure 1, a color original is mounted on an original cylinder i in the exploration part, while in the recording part a recording film

  is mounted on a recording cylinder 3, _ the two cylin-

  dres 1 and 3 being brought to rotate in synchronism by a common shaft 5 The shaft 5 is driven by a motor 6 via a speed reducer 7 The rotation of the motor 6 is also transmitted to a threaded shaft 8

  in a different gear ratio for

  ner a recording head 9 along the cylinder

  recorder 3 The rotation of the threaded shaft 8 is transmitted to a threaded shaft 11 via a speed variator 10 to drive a shooting head 12 along the original holder cylinder 1 The shooting head 12

  is associated with an original lighting device 13

  taking a light source 14, a converging lens and a mirror 106 the shooting head 12 contains color filters, photoelectric tubes, etc. and

  produces image signals according to tones and gradations

  of the original, which Image signals are sent to a color correction circuit 17 Image signals

  amplified and compensated in the torque correction circuit

  their 17 enter the recording head 9, and the recording film 4 is exposed to light for color selection images, for example by means of a source

laser beam.

  Optical recording equipment using a laser beam source A is shown schematically

  in figure 2 For the laser beam is used, because

  sound of his superiority, a He-Ne mix and as a mo-

  light emitter for the laser beam is used an optoacoustic modulator 18 The image signals obtained from the original 2 and corrected are applied, with variations in their intensity, to an optoacoustic modulator control circuit 19 to produce signals

  high frequency which control a piezoelectric transducer

  plate 20 The piezoelectric transducer 20 converts the

  high frequency signals into acoustic signals which are

  seen in an optoacoustic medium 21 Thus, when the laser beam coming from the laser beam source A enters the optoacoustic medium 21, it is diffracted by

  sound waves and thus modulated, and the laser beam emer-

  giant of this medium goes through an opening 29 in a mas-

  with openings 22 and then by a converging lens 23 to strike the recording film 4 on the cylinder

  recorder 3 to impress the film and record

  sort chromatic images

  If it is a question of drawing lines on the film of

  registration 4 per exposure using the device

  classic image exploration and recording

  crit above, the distribution of the intensity of a beam

  flat laser beam 24 emerging from the converging lens 23 is of the kind shown in FIG. 3 (a) which shows a normal distribution curve 25 around the beam Consequently, the exposure takes place in a main scanning direction 26, which is associated with the scanning in the direction of the circumference of the rotary recording cylinder 3, the film is exposed and developed in the manner shown by an area surrounded by a dotted line 27, as shown in FIG. 3 (b) o upper and lower arc-shaped portions 28 represent superfluous exposure due to an effect of contiguity produced by the exposure and the development of the film Consequently, if the exposure by scanning is carried out in the direction

  main scan 26 and the second scan direction

  26 ', as shown in Figure-3 (c), waves form in the upper and lower arc-shaped portions 28 in the transverse direction (direction of

  secondary scan 26 '); thus, straight edges cannot

cannot be obtained.

  To eliminate this drawback, we have been led to choose a concave lens shape for an opening 29 formed in a mask with openings 22, as shown in FIG. 4 However, obtaining such a shape

is storyteller.

  The present invention uses a mask with openings

  22 having a pair of circular openings 29 present

  as a diameter d and spaced apart from each other by a distance L, as shown in FIG. 5 (a) Consequently, if the exposure is carried out with this mask with openings 22 in the direction of main scan 26,

  the laser beam 24 is transformed into two tiny beams

  through the two openings 29 the distribution

  tion of intensity obtained after their passage through the converging lens is of the kind represented in FIG. 5 (c), whereas a distribution of intensity obtained by exposure and development of a film is of the kind represented in FIG. 5 ( b) as a result of the contiguity effect In the case of scanning of the film, a portion surrounded by a line in

  dotted 27 ', shown in Figure 5 (d), is exposed.

  Even if the upper and lower horizontal lines have some unevenness as a result of the exposure by scanning in the main scanning direction 26 and the secondary scanning direction 26 ', this inequality is only about 1 to 2 microns at case where, for example, d = 0.3 mm and L = 1 mm, so that they are substantially united and lines can be drawn so

  precise, as shown in Figure 5 (e).

  In summary, the present invention offers the following advantages:

  1) The respective intensities of the beams, immediate-

  after their exit from the two openings, are shown

  felt in Figure 5 (a) -but the beam intensities between the two openings overlap due to the blurring

  dt to the lens, and the effect of contiguity dt to the expo-

  development, so as to obtain a distribution

  bution of regular intensity, thus allowing to trace

  solid lines on the exposed part by scanning.

  2) Since it suffices to execute two openings

  simple tures in a thin mask, the manufacturing is ai-

  sée. It goes without saying that the shape of the openings is not limited to a circle but can be modified in various ways.

ways according to requirements.

Claims (2)

  1 mask openings intended to be used in the recording part of an exploration and image recording device, characterized in that the mask (22) has two openings (29) arranged on the path   optical beam of light to impress a sup-   recording port, the openings (29) being spaced a determined distance (X).   2 mask with openings according to claim 19   characterized in that the two openings (29) are identical   ticks from the point of view of their dimensions and form 3 mask with openings according to claim 2,   characterized in that the two openings (29) are provided   placed parallel to the secondary scanning direction (26 ') of the recording medium O 4 Mask with apertures according to Claim 3, characterized in that each of the apertures (29) has a circular shape.