JPH0460610A - image recording device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to an image recording device, in which a screen is constructed from a plurality of pixels, and an image recording device is used that corresponds to a gradation level set for each pixel. The present invention relates to an image recording apparatus that records an image ε by exposing a photoreceptor to color.

[Prior Art] This type of image recording device has conventionally been used in optical printers and the like, and for example, images are created by exposing a photoreceptor such as photosensitive paper to transmitted light emitted from the back of an LCD panel. It is known to record

LCD panel (screen is made up of multiple pixels).When a pixel is on (transparent), the light emitted from the back is passed through, and when the pixel is off (non-transparent), the light is blocked. Therefore, an image is formed by controlling each pixel on and off, and the photosensitive paper is exposed to transmitted light corresponding to the image.Then, in order to obtain multiple gradations, one The exposure amount is adjusted by repeatedly switching between the on state and the off state in a high-speed cycle during the exposure period, and controlling the ratio of the on state (duty ratio) within the exposure period. That is, by controlling the duty ratio, It is possible to change the gradation.

[Problems to be Solved by the Invention] However, in devices that obtain a plurality of gradations through such duty control, the following problems have occurred. Namely, when an LCD panel is used, it is difficult to turn each pixel on and off.
The off switching response is poor, the duty ratio varies, and the exposure cannot be controlled accurately.As a result, the degree of freedom in gradation on exposed photosensitive paper is narrowed, and only about 8 gradations can be controlled. Also, especially STN
In conventional LCDs, switching a pixel on and off affects surrounding pixels, resulting in a wide range of contrast reduction.

As a result, images cannot be faithfully expressed, leading to a decline in image quality.

The image recording device of the present invention aims to solve the above problems and improve image quality.

[Means for Solving the Problems] The image recording device of the present invention, as illustrated in FIG. In an image recording device that records an image by exposing a photoreceptor to transmitted light emitted from the screen or reflected light emitted from the front surface of the screen, the above-mentioned The gist of the present invention is to include an exposure control means that performs continuous exposure by each pixel only once for a period corresponding to a gradation level set for each pixel.

[Function 1] An image recording device of the present invention having the above configuration (a screen is constructed from a plurality of pixels, and an image is recorded by exposing a photoreceptor to light from the screen. A gradation level is set for each pixel. The exposure control means performs continuous exposure by each pixel only once for a period corresponding to the gradation level within a predetermined exposure period for exposing the photoreceptor. That is, the continuous exposure by each pixel is 1.t.
, is performed once within a predetermined exposure period for a period corresponding to the gradation level.

As a result, variations in exposure amount are reduced because one continuous exposure is performed without switching on and off of pixels in high-speed cycles as in duty control.

[Example] In order to further clarify the structure and operation of the present invention described above, preferred embodiments of the image recording apparatus of the present invention will be described below.

FIG. 2 (This is a schematic configuration diagram of an image recording device used in an LCD printer as another embodiment. Image recording device) 1
y) A lamp 3 (halogen lamp) as a light source, and a condenser lens 5 provided in order from the light source side. LCD
It includes a panel 7, an imaging lens 9, a photosensitive paper]1, and a projection control device]3.

The condenser lens 5 converts the light from the lamp 3 into parallel light and allows it to pass therethrough.Therefore, the LCD panel 7 is irradiated with parallel light.

LCD panel 7 (LCD panel 7) is a liquid crystal display device that performs dot matrix display, and controls the orientation of liquid crystal molecules depending on whether or not each pixel is energized. An image is formed and displayed by switching between the transparent and transparent lamps.The irradiated light from the lamp 3 is
If the pixel is bright, it passes through; if it is dark, it is blocked. Therefore, the projected image passing through the LCD panel 7 is
This corresponds to the image displayed on panel 7.

A projected image of the light transmitted through the LCD panel 7 is formed by an imaging lens 9.
The image is formed on photosensitive paper. Therefore, the photosensitive paper 11 records an image corresponding to the transmitted light during exposure by this transmitted light.

The projection control device 3 includes an electronic control device 5, an LCD driver 17 for driving the CD panel 7, a lighting driver 9 for lighting the lamp 3, and an operation switch 2.

The electronic control unit 15 includes a CPLJl 5a, a RAMI 5b, a ROM 15c configured as an arithmetic and logic circuit, and a video RAM (V-RAM) 1 that stores image data.
5d and the above (7) LCD driver 17, lighting driver]9. operation switch 2], an input/output interface 15e for transmitting and receiving signals, and a bus 1 for interconnecting these.
5f.

The image data stored in the video RAM 15d includes coordinate data for specifying each pixel and gradation data set for each pixel. This gradation data corresponds to the exposure period, and as shown in the timing chart of FIG. 3, the exposure period and its timing are set for each gradation level 1 to n. In the same figure, ON
indicates that the liquid crystal of the pixel is energized and its orientation is changed to bring the pixel into a bright state, and 0FF (off) indicates that the liquid crystal is not energized and the pixel is placed in a dark state. In the case of gradation level 1, the photosensitive paper] is exposed for the maximum exposure period T max by the transmitted light from the pixel to which the gradation level is set, and the corresponding area becomes white. As the gradation value increases, the exposure period is shortened to make the image darker. Also,
Exposure by transmitted light from each pixel has a maximum exposure period T m
The rising edge (exposure start time) of the tags to be performed once within the period ax is set to be the same.

Next, the exposure control processing executed by the electronic control device 15 will be explained. FIG. 4 is a flowchart showing an exposure control routine, which is activated when a print mode is selected.

First, read the image data for one frame (S100
), it is determined whether the start button (not shown) of the operation switch 21 is turned on (Stlo). The process waits until the start button is turned on, and when it is turned on, the lamp 3 is then turned on (St20). Subsequently, the LCD is driven by a drive signal according to the image data, and one frame worth of image is displayed on the LCD panel 7 (S130). That is,
As shown in FIG. 3, each pixel is turned on (bright state) for a period corresponding to the gradation data set for each pixel, and the light emitted from the lamp 3 is transmitted through and the photosensitive paper 11 is exposed. It is.

Next, it is determined whether the maximum exposure period Tmax, which is the exposure period of gradation level 1, has passed since the IQLcD was driven.
140), the process of step 130 is executed until the maximum exposure period T max has elapsed. Maximum exposure period T max
If it is determined that the elapsed time has elapsed, the exposure process for the photosensitive paper 11 has been completed, so the driving of the LCD is stopped (5150), the lamp 3 is turned off (S160), and this routine is ended.

As explained above, the image recording apparatus of this embodiment performs continuous exposure for a period corresponding to the gradation level set for each pixel only once within the maximum exposure period Tmax, and moreover, the exposure start timing is the same. I have to. Therefore, the variation in exposure amount, which is a problem with conventional duty control that repeatedly turns on and off in high-speed cycles within one exposure period, is reduced.In addition, switching on and off greatly affects surrounding pixels. becomes less. As a result, it is possible to accurately control the exposure amount according to the gradation degree, and also to increase the degree of freedom in gradation, and furthermore, it is possible to improve the contrast. Therefore, the image can be faithfully expressed and the image quality is improved.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments.
In addition to providing R, G, and B filters, R, G,
The present invention may be implemented in various ways without departing from the gist of the present invention, such as recording an image in color by switching the B screens, or an image recording device using a CRT. Of course you can get it.

Alternatively, the exposure start time for each pixel may not be the same, but one continuous exposure may be performed within a predetermined period according to the gradation level.

Effects of the Invention As detailed above, the image recording apparatus of the present invention allows each pixel to be continuously exposed only once within a predetermined exposure period for a period corresponding to the gradation level set for each pixel. As a result, variations in exposure amount are reduced and image quality is improved, which is an extremely excellent effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating the basic configuration of the present invention, FIG. 2 is a schematic configuration of the image recording device, FIG. 3 is a timing chart for explaining the exposure period, and FIG. 4 is a flow chart showing the exposure control routine. It is. ]...Image recording device 3...Lamp 7...L
CD panel 3...Projection control device 1...Photosensitive paper 5...Electronic control device

Claims (1)

[Scope of Claims] 1. A screen is constructed from a plurality of pixels, and is sensitive to light emitted from the screen, transmitted light of light irradiated from the back of the screen, or reflected light of light irradiated from the front of the screen. In an image recording device that records an image by exposing a body to light, continuous exposure by each pixel is performed once for a period corresponding to a gradation level set for each pixel within a predetermined exposure period for exposing the photoreceptor. An image recording apparatus characterized by comprising an exposure control means that performs exposure only once.