JPH0373370A - End surface luminescent type el printer - 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 Field of the Invention The present invention relates to an edge-emitting EL printer having a line head in which edge-emitting EL elements are arranged in an array.

2. Description of the Related Art In recent years, with the development of various office automation machines, electrophotographic printers have been put into practical use. This electrophotographic printer prints images by scanning a charged photoreceptor with light, developing an electrostatic latent image with charged toner, and transferring this toner image onto printing paper. It is. There are various types of such printers, but a line printer is one that is easily miniaturized and capable of high-speed printing. This performs optical scanning by selectively emitting light from light-emitting elements connected to a line head, and forms an electrostatic latent image on a photoreceptor that moves in a sub-scanning direction relative to this. .

Problems to be Solved by the Invention Since the line printer as described above prints pixels depending on whether each light emitting element emits light or not, the printed pixels are binary black and white. As a method for expressing an intermediate density from pixels having a value of black 1', there is an intermediate tone recording method such as a dither method. This dither method uses a threshold matrix in which a different threshold value is set for each pixel arranged in a matrix.
The threshold value of each pixel of this threshold value matrix is compared point by point with the density of the pixel of the image to be reproduced to determine black and white, thereby expressing a pseudo intermediate density.

However, this method inevitably results in lower resolution and lower image quality, and furthermore, the printed image is always homogeneous and monotonous, and the image expression cannot be changed as desired by the user.

Furthermore, depending on the user's wishes, printing an image with black and white inverted may be desired, but in order to achieve this, it is necessary to provide a dedicated circuit for signal processing of print data, which requires large equipment. This will lead to a decline in productivity and productivity.

Means for Solving the Problem A line head is provided in which edge-emitting type EL elements with a flat beam shape are arranged in an array, and the beam is formed by light emission from each edge-emitting type EL element of this line head A pixel pattern storage means is provided in which a plurality of patterns of approximately square pixels are set, and the plurality of pixel patterns set in the pixel pattern storage means and input print data are arranged. Accordingly, a light emission control means is provided for controlling the light emission of each edge-emitting type EL element of the line head, and a pixel pattern changing means is provided for freely changing the pixel pattern set in the pixel pattern storage means.

A line head is provided in which an edge-emitting type EL element with a flat beam shape of the active output light is arranged in an array, and flat pixel components formed by light emission from each edge-emitting type EL element of this line head are arranged. A pixel pattern storage means is provided in which a plurality of patterns of approximately square pixels are set, and each end-emitting type E of the line head is configured according to the plurality of pixel patterns set in the pixel pattern storage means and input print data. By providing a light emission control means for controlling light emission of the L element and a pixel pattern changing means for freely changing the pixel pattern set in the pixel pattern storage means, the number of pixel constituent elements printed in a pixel can be reduced. Since the pixel density can be changed by changing the pixel density, it is possible to print images that express halftones without reducing the pixel density. Since patterns can be freely set, various types of image formation can be performed.

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 to 7. First, the edge-emitting type EL printer 1 of this embodiment uses edge-emitting type E1 and element 2 as light emitting elements. As illustrated in FIG. 3, this edge-emitting type EL element 2 has a thin active layer 3 made of zinc sulfide containing an active element surrounded by dielectric layers 4.5 from above and below, and these dielectric layers 4.5. Flat plate electrodes 6.7 are formed on the upper and lower surfaces of 4 and 5. Therefore, in this edge-emitting EL printer l, the fourth
As illustrated in the figure, an edge-emitting type E I having the above structure, a line head 8 in which the elements 2 are continuously formed in an array using thin film technology, etc. are mounted on a photosensitive drum (none of which are shown) together with a charger and a developer. are arranged facing each other on the circumferential surface of.

Therefore, the circuit structure of this edge-emitting type EL printer l is such that, as illustrated in FIGS. A print data editing circuit 11 is connected, and a pixel pattern changing means 12 and a print data memory 13 are connected to this print data editing circuit 11. Here, the pixel pattern changing means 12 includes four dip switches 15 each having a four-speed pin 14.
~18. On the other hand, the print data editing circuit 11 is formed of five data selectors 19 to 23, and the bins 14 of the dip switches 15 to 18 are sequentially stored in the four data selectors 19 to 22, which also serve as pixel pattern storage means. At the same time, the print data memory 13 (ii'lj) is connected, and the data selectors 19-2 (n17) are connected.
2 is connected to the driver control circuit IO via one data selector 23.

In such a configuration, the edge-emitting EL element 2 used in the edge-emitting EL printer 1 emits light from the active layer 3 when a high voltage pulse is applied between the flat electrodes 6 and 7. Note that this emitted light has a flat beam shape and the emission intensity is about 100 times that of the conventional EL.

Therefore, this edge-emitting type EL printer 1 selectively causes each edge-emitting type EI and element 2 of the line head 8 to emit light to perform optical scanning, thereby forming an electrostatic latent image on the circumferential surface of the charged photosensitive drum. Then, printing is performed using an electrophotographic method. In addition,
This edge-emitting type EL printer 1 compresses and temporarily stores input print data, and forms one main scanning line with four optical scans, as illustrated in FIG.

This corresponds to the fact that the emitted light of the edge-emitting EL element f2 is extremely flat, and by making the flat pixel constituent elements 24 printed with one emitted light continuous in the sub-scanning direction, a substantially square shape can be obtained. A pixel 25 is formed.

Therefore, this edge-emitting EL printer l has two pixels.
By changing the number of pixel components 24 forming 5,
Halftones are expressed by changing the area ratio of black and white in one pixel 25. In other words, when one pixel 25 is formed by emitting light four times as described above, the number of pixel constituent elements 24 to be printed in one pixel 25 may be changed to non-white, grayscale, etc., as illustrated in FIG. : By using one for J41, two for gradation 2, and four for black, four-step gradation can be expressed geometrically from self to black. Here, as illustrated in FIG. 7, the pixel 25 consisting of the four pixel components 24 has a maximum of five density gradations and a pattern of 2゛=16i, and this is the 4-bit control data r0000J to r l
l l 1. It is registered in the print data editing circuit 11 as J.

On the other hand, if the print data is formed with 2 bits for pixel 25, this is roO' from white to black.
There are four stages: , roiJ, rloJ, and ml.

Therefore, in this edge-emitting type EL printer l, the pattern of pixels 25 to be printed for each print data is set in advance in the print data m collection circuit 11 by the pixel pattern changing means 12. Here, one row of pattern settings for this pixel 25 is illustrated in the pattern table below.

Therefore, in this edge-emitting EL printer l, for example, print data including density data input from the print data memory 13 is
If it is "01", print pixel 25 of pattern No. 2 and rl
In the case of lJ, pixel 25 of pattern No. 16 is printed to print an image expressing halftone without reducing pixel density.

Furthermore, in this edge-emitting type EL printer 1, the setting of the pixel 25 pattern for the print data as described above can be changed by operating the dip switches 15-18. In other words, by operating four dip switches 15 to 18 each having four bins 14, 4-bit data can be set to four data selectors 19 to 22, and these data selectors 19 to 22 The pattern No. 16 of the pixels 25 to be printed can be freely set for the detected four-gradation print data.

In other words, this edge-emitting type EL printer 1 can change the number of pixels 25 to be printed based on the print data by changing the contents of the pattern table according to the user's (not shown) wishes.
For example, in addition to changing the density of the printed image, you can also change the contrast strength to create black and white (black and white) patterns.
It is also easy to switch to FtE image printing or print an image with black and white inverted.

In the edge-emitting EL printer 1 of this embodiment, the pattern of the pixels 25 to be printed is set using the dip switches 15 to 18 for each data selector 19 to 22 corresponding to each print data. The present invention is not limited to the above structure, but, for example, a pixel pattern as described above is recorded in a memory such as a ROM, and the pixel pattern corresponding to each print data is selected using a keyboard. (not shown) is also possible. The number of pixel components 24 forming one pixel 25 is determined based on the performance of the optical system, the sensitivity of the photoreceptor, etc. Furthermore, the number of pixel components 24 forming one pixel 25 is determined based on the performance of the optical system, the sensitivity of the photoreceptor, etc. It can also be prevented.

Effects of the Invention As described above, the present invention provides a line head in which edge-emitting type EL elements with a flat beam shape of emitted light are arranged in an array. A pixel pattern storage means is provided, in which a plurality of patterns of substantially square pixels in which flat pixel components are arranged are set, and the plurality of pixel patterns set in the pixel pattern storage means and input print data are combined. Accordingly, four stages of light emission control are provided to control the light emission of each edge-emitting type EL element of the line head, and a pixel pattern changing means is provided to freely change the pixel pattern set in the pixel pattern storage means. The pixel density can be changed by changing the number of pixel components printed on the image, so it is possible to print images that express halftones without reducing the pixel density. The pixel pattern printed for data can be freely set, so in addition to changing the density of the printed image, you can also change the contrast strength to switch to black and white binary image printing, or print an image with black and white reversed. It is also easy to print, and has the advantage of being able to print in various forms freely and forming images with a high degree of freedom.

lag diagram, Figure 3 is a perspective view showing an edge-emitting EL element, Figure 4 is a perspective view showing a line head, Figure 5 is an explanatory diagram showing a printed image, and Figures 6 and 7 are pixel patterns. FIG.

l... Edge WJ light emission type EL printer, 2... Edge emission type EL element, 8... Line head, 11... Light emission control means, 12... Pixel pattern changing means, 19-22
...Pixel pattern storage means

Claims (1)

[Claims] A line head is provided in which edge-emitting EL elements with a flat beam shape of emitted light are arranged in an array, and flat pixel components formed by light emission from each edge-emitting EL element of this line head are arranged. A pixel pattern storage means in which a plurality of square pixel patterns are set is provided, and each edge emitting type EL element of the line head is arranged according to the plurality of pixel patterns set in the pixel pattern storage means and input print data. 1. An edge-emitting EL printer comprising: a light emission control means for controlling light emission; and a pixel pattern changing means for freely changing a pixel pattern set in the pixel pattern storage means.