JPS6359256A - Image writer - Google Patents

Abstract

PURPOSE:To lower memory cost, by constituting the valid write width of a write head at a succeeding stage smaller than that of the write head at a preceding stage. CONSTITUTION:Two write heads 21 and 22 are arranged so as to be shifted with each other in a scanning direction, and a writing valid width is extended longer than ever. At this time, the valid width l22 of the write head 22 arranged at the succeeding stage is set narrower (shorter) than the valid width l21 of the write head 21 arranged at the preceding stage. To write an image on the same line correctly, a picture signal is impressed on the write head at the succeeding stage with a timing delayed by a prescribed time behind impression on the write head at the preceding stage. Since the write width of the write head at the succeeding stage is set narrower than that of the write head at the preceding stage, it is possible to reduce the memory capacity of a buffer in which the picture signal being impressed on the write head at the succeeding stage, is stored transiently.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image polishing device that forms an image according to an electrical input signal, and is applicable to a thermal writing device such as a thermal head, a multi-tilus, etc. It is applied to electrostatic writing devices, optical writing devices using liquid crystals, LEDs, etc., magnetic writing devices using magnetic heads, or devices that directly write images on paper, such as inkjet devices.
The present invention relates to an image aS imprinting device suitable for forming images on large-sized paper.

[Prior Art] In recent years, the automation of information processing has been significantly promoted, but on the other hand, the need for conventional hard copies has not diminished, and the use of printers and plotters to obtain hard copies from electrical input has continued. Demand is actually increasing. This trend is progressing not only in office processing, but also in the fields of science, technology, and design development, and with CAD/CAM systems, there is a demand to obtain hard copies on large-sized paper using electrical input. strong.

However, printers and plotters that form images on large-sized paper naturally have larger devices.
The reality is that the cost also increases.

Conventionally, a laser printer is a typical example of a printer that is connected to an electrical input and can produce high-quality images at high speed. Laser printers, which print images by rotating and scanning a light beam, are inherently unsuitable for outputting large-sized images due to issues such as device size, speed, cost, and image quality (jitter). do not have. In addition, in devices such as line printers that do not rely on beam scanning, such as laser printers, it is relatively easy to create a large-sized printer by widening the scanning width for one line. , creating long write heads,
There was still a problem in terms of cost.

FIG. 4 shows an example of the configuration of a conventional large-size image writing device. The image writing device shown in FIG. 4 has two writing heads 1 having an effective writing width of 11.12.
, 2 are arranged side by side and shifted by an interval d back and forth in the scanning direction. Each write head 1, 2 does not have an effective writing width to its ends;
Since the total length L1 of one write head itself is longer than the effective write width l and I2, simply butting them together will result in a non-writable area in the center of the butt. Therefore, as shown in FIG. 4, by arranging two floating heads so as to be shifted back and forth by a distance d, both effective writing widths can be increased. , 12 may form a substantially aligned write head.

For example, with two write heads of A4 size (effective writing width 210 m), A2 size (effective writing width 420 m)
am) images can be written.

However, in the conventional device described above, when an image is written by scanning the image forming member in the direction of arrow A in FIG. 4 at a relative speed ν with respect to the writing head 1.2, the image is correctly written on the same line. In order to write, the subsequent write head 2 is moved by a time d/ν from the previous write head 1.
It is necessary to output the image signal at a delayed timing.

Therefore, as in the image signal processing circuit shown in FIG.
A memory buffer 7 is required to store the amount of drV pits. (Note that l and rV are the pixel densities in the axial direction and scanning direction of the head, respectively.) Generally, rH= rV=
If r, then a memory of 12 dr pits is required.

The image signal processing circuit shown in FIG. 5 above is configured as follows.

In the figure, 101 is an external input signal source, such as a host device that creates a document or image using a computer, word processor, etc. and sends out the signal as a code signal or video signal, or an image input device equipped with a reading sensor such as a facsimile. It is. 102 is an image writing device, 6
1 is a pattern generation section provided in the image aI writing device, which converts the code signal and video signal sent from the input signal source 101 into a pit pattern according to the writing order.
, output as a video signal for each scanning line.

At this time, the image signal on the same image line is divided into two image signals to be applied to the write head 1 at the front stage and the write head 2 at the rear stage, respectively. One of the two image signals is directly applied to the writing head 1 at the previous stage. The other divided image signal is then stored in the memory buffer 7, and the stored image signal is read out with a certain delay time and applied to the write head 2 at the subsequent stage. It is configured as follows. Therefore, on the image forming member (not shown), as a result, the original one-line image is written at the same position, and a desired image is obtained.

[Problems to be Solved by the Invention] However, in the above-mentioned image @ reading device shown in FIG. -I1
2, but as high pixel density has become required in recent years, the memory buffer 7 mentioned above needs to have a large memory capacity, which poses the problem of increasing memory cost. .

This invention was made in view of the above points,
The purpose is to provide an image writing device that can reduce memory costs by making the effective writing width of the writing head in the latter stage narrower than the effective writing width of the writing head in the preceding stage. There is a particular thing.

[Means for Solving the Problem] The image writing device according to the present invention solves the problem by making the effective writing width of the writing head placed in the latter stage narrower than the effective writing width of the writing head placed in the preceding stage. We are trying to

[Operation] In order to correctly whiten an image on the same line, an image signal is applied to the writing head at the subsequent stage at a timing delayed by a predetermined delay time from the writing head at the preceding stage.

In the image writing device according to the present invention, since the write width of the output head at the rear stage is narrower than that at the front stage, the image signal applied to the write head at the rear stage is -
The memory capacity of the memory buffer for H memory can be made smaller compared to the conventional one.

[Embodiment] An embodiment of the image writing device according to the present invention will be described based on FIGS. 1 to 3.

First, a first embodiment of the present invention shown in FIG. 1 will be described.

FIG. 1 is a plan view showing the arrangement of the image 8i writing head, in which two writing heads 21 and 22 are arranged offset in the scanning direction to increase the effective writing width. At this time, the effective width of the pI insertion head 22 located at the rear stage'
22 is the effective width of the write head 21 placed at the front stage.
It is narrower (shorter) than 21. The capacity of the memory buffer required in this case is “1 −d−r −
(122<12)", which makes it smaller than the conventional one.

Therefore, it is possible to provide an image writing device having a long effective width at a lower memory cost than the conventional one.

Next, a second embodiment of the invention shown in FIG. 2 will be described.

This second embodiment uses three write heads to
Efforts are being made to increase the effective width. Two writing heads 31 and 32 are arranged side by side on the same axis line in the front stage,
In order to fill the gap between the connecting portions of the two, a write head 33 at the latter stage is arranged. The effective write width '33 of the write head 33 is (131-731) x 2, and this length is 1 of the effective write width of the entire image writing device.
It can be reduced to about 15 to 1/20. therefore,
Memory puff required for this latter stage write head 33?
7 can be significantly reduced in memory capacity.

A third embodiment of the invention shown in FIG. 3 will be described.

Depending on the type of fortune-telling head used,
Alternatively, due to manufacturing technology, there are some devices that can only be manufactured with an extremely short effective writing width. In that case, the third
As shown in the figure, by increasing the number of write heads by connecting them using write heads 51 and 52,
Theoretically, any number of long write heads can be implemented.

In this case as well, by using a write head shorter than that of the set of write heads 51 at the front stage for the navy blue color of the output head 52 at the rear stage, it is possible to reduce the number of required memory buffers.

According to the image writing device according to the present invention, since the effective writing width of the writing head in the latter stage is configured to be narrower than the effective writing width of the writing head in the preceding stage, the memory capacity of the memory buffer can be reduced and the cost can be reduced. A long image writing device can be provided. Also, when it is technically difficult to make a long writing head,
By combining multiple short writing heads, the same functionality as a long writing device can be obtained. Furthermore, since a large number of standard-sized writing heads can be used, the structure can be constructed at low cost.

[Brief explanation of the drawing]

1 to 3 show an embodiment of an image writing apparatus according to the present invention, and FIGS. 1, 2, and 3 are plan views showing the arrangement of a writing head. 4 and 5 show a conventional example, in which FIG. 4 is a plan view showing the arrangement of a write head, and FIG. 5 is a block diagram showing an image signal processing circuit. [Explanation of symbols] 1, 21.31.32.51. ; Previous stage country cutting head 2.22, 33, 52. Later writing head patent applicant Fuji Xerox Co., Ltd. Representative Patent attorney Satoshi Nakamura
Hiroshi (2 others) Figure 1 Figure 2 Figure 3

Claims (2)

[Claims] (1) A pair of write heads are arranged at the front and rear stages so that the effective write widths do not overlap each other in the scanning direction, and the entire effective write of the pair of write heads is performed by scanning in a direction perpendicular to the pair of write heads. An image writing device for writing an image of the same size as the width, characterized in that the effective writing width of a writing head at a subsequent stage is configured to be narrower than the effective writing width of a writing head at a preceding stage. (2) Delay means including a memory buffer for applying an image signal to be applied to a subsequent writing head among image signals on the same image line with a delay of a predetermined delay time from an image signal applied to a preceding writing head. An image writing device according to claim 1, characterized by comprising:.