JPH02122952A - Electrostatic recorder - Google Patents

Abstract

PURPOSE:To reduce coarse density irregularities significantly as found when the whole recorded image is viewed even during high-speed recording by allowing data to be recorded for each line in a scan direction on a recording medium driven and fed in a subscan direction, and at the same time, reversing the order of drive each time a specified number of lines are recorded. CONSTITUTION:Data for specifying a recording position a'0 to a'n are written in advance at the top of ROM 5 for specifying a recording position so that data is recorded from the center of a scan line to both ends of the line. In addition, the data for specifying a recording position a'0 to a'n are written in advance at the bottom of ROM 5 so that data is reversely recorded from both ends of the scan line to the center of the line. Then count data a0 to an, aL for specifying the addresses in ROM 5 are incremented, and a single block of image data is allowed to be recorded sequentially at a recording position designated for each count value. Thus the order of a specified recording position is reversed each time a single line of record is completed. Subsequently, density variations in the scan line are viewed as they are averaged or cancelled, making the density irregularities less conspicuous.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrostatic recording device having a multi-stylus electrostatic recording head.

2. Description of the Related Art In a conventional device of this kind, as shown in FIG. 3, a large number of needle electrodes 1 arranged in the main scanning direction X are connected to a plurality of needle electrode blocks 1-1. 1-2. 1-3. 1-4,...
Each needle electrode block 1-
1. 1-2. 1-3. 1-4.・・・・・・・・・
A plurality of control electrodes 2-1.2-2.2-3°2-4. . . . has a multi-stylus electrostatic recording throat 3 arranged along the needle electrode 1, and drives the needle electrode 1 in block units and in a fixed order in a time-division manner. As a result, recording is performed line by line in the main scanning direction X on a recording medium that is fed and driven in the sub-scanning direction Y (for example, Japanese Patent Laid-Open No. 59-38073,
JP-A-56-166082, JP-A-62-216
(See Publication No. 56).

Problems to be Solved by the Invention However, with this configuration, there is a problem in that density unevenness tends to occur over the entire recording screen when recording is performed at high speed.

The above problem arises for the following reasons.

That is, in this type of recording apparatus, the needle electrode 1 is driven by applying a positive control voltage Vp to the control electrode 2 side and applying a negative recording voltage Vn to the needle electrode 1 side. The sum Va of both voltages Vp and Vn (Va=V
Electrostatic recording is performed by applying n+Vp) to a recording medium (recording paper).

In this case, the needle electrodes 1 are, for example, odd-numbered needle electrode block groups 1-1.1-3. . . . and even numbered needle electrode block group 1-2. 1-4. ·river·····
The recording voltage Vn is applied to each group.

Control electrode 1-1. 1-2. 1-3. 1-4.・・・
. . , two adjacent ones in the main scanning direction X are sequentially selected and the control voltage Vp is applied to them.

At this time, between the needle electrode 1 and the control electrode 2, as shown in FIG. Thus, a so-called OR type transient circuit is formed with equal constraints. With this transient circuit, as shown in FIG. 6, when the positive pulse voltage Vp of the control electrode 2 is applied, the potential Vp' at the recording section changes to the negative potential side immediately after the application of the positive pulse voltage Vp. Becomes oversheeted.

For this reason, for example, as shown in Table 1, the application position of the control voltage Vp is changed to needle electrode block 1-1. 1-2゜1-3. 1
-4. ......, when recording is performed by moving in the arrangement order of 1-m, that is, the needle electrode 1 is driven by the needle electrode block 1-1.1-2.1-3.1-4 degrees.・・・・・・・・・
. . , 1-m in the arrangement order, control electrodes 2-2, 2-3, other than those located at both ends. . . . The positive pulse voltage Vp is applied to each of 2-m twice in succession.

Control electrodes 2-3, 2-4, to which positive pulse voltage Vp is applied twice in succession. ......, 2-m are the first pulse voltage Vp, respectively, as shown in FIG.
The second pulse voltage Vp is applied while the influence of the oversheet immediately after the application of Vp remains. As a result, each control electrode 2-2.2-3.・・・・・・
..., the recording part potentials vp' and Vp''' of 2-m are different between the first and second times, and the recording part potential vp'' at the time of the second voltage application is the same at the time of the first voltage application. A situation may occur in which the recording section potential Vp' is lower than that of the recording section potential Vp'.

This potential drop causes density unevenness between the needle electrode blocks.

Table 1 Therefore, as shown in Table 2, for example, needle electrode block 1
-1.1-2.1-3.1-4. By performing the 1-m drive skipping every other control electrode, the time interval between applying the pulse voltage Vp to the same control electrode is increased, and the above-mentioned overflow caused by the first voltage application is avoided. It has been proposed to prevent the influence of the sheet from remaining until the next voltage application (Japanese Patent Laid-Open No. 56-16
6082, JP-A-69-38073).

Margin Table 2 Below - However, although the above-mentioned method may reduce the unevenness of recording density between adjacent or adjacent blocks, as the recording speed is further increased, recording of multiple blocks becomes more difficult. Even after the line has been removed, the influence of the opaginite remains, resulting in uneven density across the entire line. This density unevenness across the entire line is very noticeable when viewed as a whole recording screen, that is, when viewed from a macroscopic perspective.

The present invention has been made in view of the above-mentioned problems, and can be achieved without complicating the configuration of the device, especially the drive system of the needle electrode.
An object of the present invention is to provide an electrostatic recording device that can significantly reduce macroscopic density unevenness when observing the entire recording screen even when recording is performed at high speed.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention drives the needle electrodes of a multi-stylus electrostatic recording head in block units in a time-division manner. In this embodiment, recording is performed line by line in the main scanning direction, and the driving order of the blocks is reversed every time a certain number of lines are recorded.

Effect of the Invention With the above-described configuration, the density unevenness that occurs for each line is reversed between adjacent or adjacent lines, so that the density difference in the main scanning line direction is averaged out in the sub-scanning direction. In order to be able to observe the entire recording screen without complicating the configuration of the device, especially the driving system of the needle electrode, even when recording is performed at high speed, This makes it possible to significantly reduce density unevenness.

Embodiment FIG. 1 shows a schematic configuration of an electrostatic recording apparatus according to an embodiment of the present invention. First, a large number of needle electrodes 1 arranged in the main scanning direction X are connected to a plurality of blocks 1-1. 1-2.1
-3.1-4. Each needle electrode block 1-1.1-2.1-3.1-4
．． A plurality of control electrodes 2-1 corresponding to...
．． 2-2. 2-3.2-4. . . . has a multi-stylus electrostatic recording head 3 arranged along the needle electrode 1. Needle electrode block 1-1. 1-2. 1
-3. 1-4. The needle electrodes in . . . are the odd-numbered needle electrode block groups 1-1.1-3.・・・・・・
...and even numbered needle block n1-2゜1-4.・
. . . , and in each group, blocks that correspond in position to each other are commonly connected.

Furthermore, the electrostatic recording device shown in FIG.
A decoding circuit 6 for selecting the control electrode 2 based on specifications in the read-only memory) 5 and ROM 6 is provided.

The RAM 4 stores image information PIxO to PIxm read out from the ROM 6 and designated by the recording position designation takes a'0 to a'n and stored at the designated addresses.
Output. Image information P output from this RAM 4
Based on I x O% P I x m, each needle electrode block 1-1. 1-2. 1-3. 1-4.
A negative pulse voltage is selectively applied to the needle electrodes inside.

The ROM 5 is addressed by the count data ao=an, aL that circulates once every 1 rai/recording, and outputs the recording position designation data a'o=a'n stored in advance at the designated address. It is given to RAM 4 and decoding circuit 6 as address data, respectively.

In this case, the most significant bit aL of the count data aO to an, aL serving as the address input to the ROMB is set to alternately "0" and "pa1" for each recording of one line.In other words, the ROM5 The address space is the lower space specified by the count data aO to an when the topmost pin)aL is "0" and the bottom space specified by the count data aO to an when the topmost bin)aL is 0.
The lower space and the upper space have the same size, and no matter which address space is designated, the recording position designation data a '0 to an are read and output.

However, the recording position designation data a'0 to a'n stored in the lower space and the upper space, respectively, are in a relationship such that the order of designation of the recording position by counting up the count data aO to an is opposite to each other. It has become. As a result, each time the most significant bit aL switches between "O" and "1", that is, each time one line of recording is completed, the control electrodes 2-1.2-2.2-3.2-4...・・・・・・
・The order of voltage application is reversed.

As described above, the multi-stylus electrostatic recording head 3
By time-divisionally driving the 0-needle electrode 1 in block units, recording is performed line by line in the main scanning direction X on the recording medium fed and driven in the sub-scanning direction Y.
The above needle electrode block 1-1.1 each time a line is recorded.
-2.1-3゜1-4. A configuration is obtained in which the driving order of . . . is reversed.

The operation of the electrostatic recording apparatus configured as described above will be described below.

First, in the upper space of the ROM 5 for specifying the print position, print position specifying data a'0 to an that causes printing to be performed in the order from the center to both ends of the main scanning line are written in advance. Further, in the lower space, contrary to the above, recording position designation data a'0 to a'n are written in advance so that recording is performed in the order from both ends of the main scanning line toward the center.

Under such preparation, the count data aQ=an, aL for specifying the address of the ROM 5 is counted up one by one, and one block of image information is recorded at the recording position specified for each count value. If you do it sequentially,
The designated order of recording positions is reversed every time recording of 1 lie/minute is completed.

In this way, if the designation order of the recording positions is reversed line by line, the control electrodes 2-1.2-2.2-3.2- 4. . . . The recording density distribution state, that is, the density unevenness state, which changes depending on the order of voltage application, is also reversed line by line.

As a result, even if density unevenness occurs in each line, the state of the density unevenness that occurs is reversed between adjacent lines. As a result, density differences in the main scanning line direction are averaged or canceled out in the sub-scanning direction, making macroscopic density unevenness less noticeable when observing the entire recording screen. .

In the above manner, for example, the ROMe for specifying the recording position is
With a relatively simple configuration such as adding 1 bit to the address data of s, it is possible to observe the entire recorded area even when recording is performed at high speed without complicating the device configuration, especially the needle electrode drive system. Macroscopic density unevenness in this case is greatly reduced.

Note that when the recording density or recording speed of a line is particularly high, the order in which recording positions are designated may be made for each of a plurality of lines.

Effects of the Invention As is clear from the above explanation, the present invention has the advantage of time-divisionally driving the stylus electrodes of a multi-stylus electrostatic recording head in units of blocks, thereby providing a main effect on a recording medium that is fed and driven in the sub-scanning direction. By recording one line at a time in the scanning direction and by reversing the driving order between the blocks each time a certain number of lines are recorded, the density unevenness that occurs for each line is contiguous or close to each other. As the lines are reversed, the density difference in the main scanning direction is averaged or canceled out in the sub-scanning direction, which complicates the device configuration, especially the needle electrode drive system. This has the effect that even when recording is performed at high speed without causing any problems, it is possible to significantly reduce macroscopic density unevenness when observing the entire recording screen.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an electrostatic recording device according to an embodiment of the present invention, FIG. 2 is a diagram showing the recording density distribution state of lines recorded by the same device, and FIG. 3 is a diagram of a conventional electrostatic recording device. Figure 4 is a diagram showing the filtration crossing circuit formed with equal constraints between the control electrode and the needle electrode, and Figure 6 is a diagram showing the state of potential drop of the control electrode, which causes concentration unevenness. FIG. 1... Needle electrode, 2.2-1.2-Rei 2-3.2-4,
... Control electrode, 3... Multi-stylus electrostatic recording head, 4... R, AM for image information storage, 6...
- ROM for recording position designation, 6... decoding circuit for control electrode selection. Name of agent: Patent attorney Shigetaka Awano and 1 other person: No. 2-r No. 2 7-3. Medicine chart chart

Claims (1)

[Claims] a multi-stylus electrostatic recording head having a large number of needle electrodes arranged in the main scanning direction divided into a plurality of blocks, and a plurality of control electrodes corresponding to each needle electrode block;
By time-divisionally driving the needle electrodes in blocks, the recording medium, which is fed and driven in the sub-scanning direction, is recorded one line at a time in the main scanning direction, and each time a certain number of lines are recorded, An electrostatic recording device comprising a control means for reversing the driving order of the blocks.