JPS58179053A - Optical recorder - Google Patents

Abstract

PURPOSE:To improve the reproducibility of gradation, by using a fixed light emitting element to a light source to vary the driving current which is applied to said light emitting element in response to the concentration value of a picture and to vary the driving current value in response to the exposure value-concentration characteristics of a photoreceptor. CONSTITUTION:A light source driving circuit 5 controls a driving current I which is given to a semiconductor laser 1 in response to the picture information given from a buffer memory 6, the luminance modulating signal given from a luminance modulating circuit 51 and the signal given from an optical output controlling circuit 52. The circuit 51 receives the luminance information (signal showing gradation) given from the memory 6 and obtains a luminance signal corresponding to the luminance information and at the same time gives a slight correction to the luminance signal with a compensating signal read out of a memory means 7. This compensated luminance signal is applied to the circuit 5. The circuit 5 applies the current I corresponding to the luminance signal applied after compensation to the laser light source 1. Therefore the optical output given from the source 1 varies in response to the concentration value of a picture as well as to the exposure value-concentration characteristics of a photoreceptor.

Description

[Detailed Description of the Invention] [Technical Field to Which the Invention Pertains] The present invention utilizes optical signals to generate signals and l! This invention relates to an optical recording device that records and displays information such as Ii and others.

More specifically, the present invention allows a galvanometer to scan a light beam from a light source onto a recording medium using an optical deflection means such as a mirror or a polygon mirror, and records an image as a set of dots (l[lIi elements). An optical recording device capable of expressing halftones.

[Description of prior art]

Conventional devices of this kind use an H.-Ne laser light source as a light source, make one dot into multiple dots, and change the ratio of white and black dots within one dot to express halftones. There is something that is possible. However, in such conventional recording apparatuses, it is difficult to express halftones appropriately, and the circuit means for expressing halftones is also complicated.

[Object of the present invention]

An object of the present invention is to realize an optical recording device with a simple configuration and excellent gradation reproducibility.

[Summary of the invention]

The device according to the present invention uses a solid-state light-emitting element, particularly a semiconductor laser or a light-emitting diode (llCD'), as a light source, and a drive voltage fIIl applied to the solid-state light-emitting element.
The gradation m (value indicating gradation) of the t-1 image is changed in accordance with VC, and the value of this current is changed in relation to the cod light amount-density characteristic of the photoreceptor. It is.

[Explanation of Examples]

FIG. 1 is a block diagram showing an example of the apparatus according to the present invention, and FIG. 2 is a perspective view of the main parts thereof.

In these figures, 1 digit semiconductor laser or FiLE
2 is a focusing lens, and 3 is a light deflecting means for deflecting the light beam from the light source 1. In this case, a polygon mirror is used as an example.

With 4 photosensitive drums, the surface of this photosensitive drum 4 (photosensitive surface)
A light spot from the laser light source 1 is projected and scanned. In the drive circuit for the five light sources 1, a drive circuit 52 for supplying the laser light source IK is an optical output control circuit which receives, for example, an output from a photoelectric conversion element 55 enclosed within a semiconductor laser. This photoelectric conversion element 55 includes a laser light source 1
A part of the output light from is incident. Reference numeral 6 denotes a buffer memory, in which information to be recorded (including luminance information) is sequentially stored in the form of a set of dots, for example, for one raster or one sheet.

Then, the signal read from here is transmitted to the light source drive circuit 5.
At the same time, the brightness information is output to the brightness modulation circuit 51. 60 is a counter that specifies the start address of the buffer memory 6, and 61 is the output of the counter 6D.
This is a clock oscillator to which K is applied. Reference numeral 7 denotes a memory means coupled to the brightness modulation circuit SIK, in which characteristics indicating the relationship between the exposure amount of the photosensitive drum 4 and the recording density are stored in advance.

Reference numeral 8 denotes a timing control circuit to which a timing signal from the light beam scanning position detection means 80 is applied, and controls the rotation of the light deflection means 5 and the photosensitive drum 4 via the drive motor 30 and the drive motor 40. It's in control.

It is to be noted that eight memory means and nine brightness correction circuits are used to realize uniform speed scanning without using an fθ lens or the like, and the brightness is corrected according to the deflection angle of the beam. This memory means 81. The brightness correction circuit 9 is not necessarily required.

The operation of the device configured in this way will be explained below with respect to the laser light source IK,
An example in which a semiconductor laser is used will be explained.

FIG. S is a diagram showing the relationship 1 between the driving current (2) of the semiconductor laser and the optical output. As is clear from this diagram, the optical output of the semiconductor laser can be changed almost linearly by changing the magnitude of the drive current I.

FIG. 4 is a characteristic diagram (γ characteristic diagram 4I) showing the relationship between the original density f (specific exposure il) of the photosensitive surface of the photosensitive drum 4 and the recording Iji intensity. As shown in the figure, there is a non-linear relationship between the two. This characteristic diagram is stored in the memory means 7 in advance.

The light source drive circuit S supplies a drive current to the semiconductor laser 1!
, image information from the buffer memory 6, brightness modulation circuit 5
The control is performed according to the brightness modulation signal from S1 and the signal from the light output control circuit S2. Note that the self-light output control circuit 52 is provided assuming that the light output from the laser light source changes depending on the ambient temperature, and when the light output of the laser light source is not affected by temperature changes, etc. This optical output control circuit 52 is not necessary.

The brightness modulation circuit 51 receives bright germ information (signal indicating gradation) from the buffer memory 4, obtains a brightness signal corresponding to this brightness information, and stores this brightness signal in the memory means 7.
The luminance signal is slightly modified using the correction signal read from the luminance signal, and the modified luminance signal is applied to the light source drive circuit 5. The light source drive circuit 5 provides the laser light source 1 with a drive current (2) according to the applied corrected luminance signal. Therefore, the light output from the laser light source 1 changes in accordance with the gradation value (value indicating gradation) of the image, and also changes in relation to the exposure amount-density characteristic (γ characteristic) of the photoreceptor. ,by this,
Recording with excellent gradation reproducibility can be performed.

Note that in the above description, a case where a photosensitive drum is used as the photosensitive member is exemplified, but photosensitive paper may also be used.

In this case, the memory means 7 stores the gamma characteristics of the photosensitive paper used. Further, as the light source, various kinds of solid-state light emitting element laser light sources can be used as long as the light output changes depending on the magnitude of the drive current.

[Effects of the present invention]

As described above, according to the present invention, it is possible to realize an optical recording apparatus having a simple configuration and excellent i-tone reproducibility.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing an example of the device according to the present invention, Figure 2 is a perspective view of the main parts, and Figure 3 is a drive current and optical output of the laser light source used in the device shown in Figure 1. FIG. 4 is a characteristic diagram showing the relationship between the original density of the photosensitive drum and the image recording device. DESCRIPTION OF SYMBOLS 1...Laser light source, 5...Photometering means, 4...Photosensitive drum, 5...Light source drive circuit, II...Brightness modulation circuit, 6...Buffer memory, 7...Metal Hair removal method.

Claims (1)

[Claims] (1) In an optical recording apparatus in which a light beam from a light source is scanned onto a photoreceptor by a light deflection means and ms is recorded as a set of dots, a solid-state light emitting element laser light source is used as the light source, and this The driving current applied to the laser light source is changed in accordance with the gray level of the image, and the current value of this driving 1 is changed in relation to the exposure amount-density characteristic (γ characteristic) of the photoreceptor. Characteristic optical recording device.