JPH02194955A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To apparently correct a void created by the defective feeding of a material to be recorded at the time of sub-scanning by providing a preliminarily jet-out orifice and a means detecting the recorded state corresponding to the preliminary jet-out orifice. CONSTITUTION:It is assumed that a pattern (a) is divided into two lines and recorded. After the 1st line is recorded, sub-scanning is carried out. Then, a head unit 1 is moved reversely to recording, and at this time a light emitting diode 4 is lit. By illuminating a recording paper area corresponding to the preliminary jet-out orifice 3, a phototransistor 5 detects the recording state of the area. Since a pattern (d) with a void is recorded if paper is excessively fed, no recorded dot is detected from the recording paper area corresponding to the preliminary jet-out orifice. When the subsequent 2nd line is recorded, an ink drop is jetted out of the preliminary jet-out orifice 3 together with a jetted ink drop from a jet-out orifice 2, and dots D are recorded as a pattern (e) shows.

Description

Detailed Description of the Invention [Industrial Application Field] Unreleased Ill relates to inkjet recording devices, and is particularly concerned with so-called white spots that appear in the recording of recording medium balls due to poor feeding of the recording medium for sub-scanning. The present invention relates to an inkjet recording apparatus having means for correcting streaks.

[Prior Art] Inkjet printers have the advantages of low noise, miniaturization, and easy color printing, and have recently been used in various fields as output devices for computers, word processors, and the like.

Among these inkjet printing apparatuses, there is a serial type inkjet printing apparatus in which the number of ejection orifices in a printing head can be relatively small, and printing is performed by main scanning and sub-scanning while the printing head is moved back and forth.

The sub-scanning is performed by intermittently feeding the recording medium a predetermined distance in synchronization with the reciprocating movement of the recording head.

[Problem to be Solved by the Invention 1] However, the feeding of the recording medium in a serial type inkjet recording device may differ depending on the properties of the medium used, and the accuracy of the feeding mechanism may deteriorate with long-term use. Subject to change.

If such a feed abnormality occurs, 1. For example, in the case of solid recording, line-shaped recording gaps (so-called white stripes) may appear along the Y scanning direction, reducing the quality of recording. .

[Means for Solving the Problems] As a means for solving the above-mentioned problems, the present invention provides an IU/JJ that performs recording by ejecting f'//7 from an ejection port of a recording/rad onto a recording medium. j+ 1. In the recording device, a spare ejection port is provided adjacent to +iQ ejection [], and has means for detecting the recording state of the recording medium area corresponding to the preliminary ejection [1]. characterized by
It provides an inkjet recording device.

The present invention also provides an inkjet recording apparatus characterized in that the recording head ejects ink using thermal energy.

[Embodiment] FIG. 2 is a schematic diagram showing the mechanical parts of a serial type inkjet recording device according to the present invention.

In the figure, reference numeral 1 denotes a recording head unit, which uses thermal energy to eject ink, and the recording head unit is mounted on a carriage 6.
Fixed. The carriage 6 is a rotating section that moves back and forth along the guide shaft 7, and 18 is a feed screw for feeding the carriage. The feed screw passes the page through the carriage 6,
- A head feeding pulse motor 23 is connected to the end. The recording operation of the head unit 1 is driven by a head drive circuit 41, and the head drive pulse motor 2
3 is a platen driven by a carriage drive circuit 43; 21 is a platen for holding the recording paper 20 which is a recording medium; the platen is driven by a paper feed nI pulse smoke 2;
A pulse motor 22 for feeding waste paper is rotated by
is driven by a platen drive circuit 50.

The head drive circuit 41, carriage drive circuit 43, and platen drive circuit 50 are controlled by a system control circuit 42.

During recording, when the head unit 1 moves in the direction of arrow S (main scanning direction), ink droplets are ejected from the ejection ports of the head unit 1, and one line of a predetermined width is recorded on the recording paper 20 (main scanning direction). scanning), then the platen 21 moves in the direction of arrow R.
After being rotated by a predetermined angle in the direction (sub-scanning direction) (sub-scanning), the main scanning direction is similarly turned around.

Figure 1 shows the inkjet recording device shown in Figure 2.
This is a diagram showing the first embodiment of the unit, viewed from the platen side.

In FIG. 1, 2 is the ejection port 1 used for constant recording, and 63, which are arranged in a vertical row, is adjacent to the uppermost ejection port of the ejection ports 2. This is a preliminary ejection port arranged above.A 9! photo diode 4 is arranged as a light emitting element on the left side of the preliminary ejection port 3, and a photo diode 4 as a light receiving element is arranged on the right side of the ejection port 3. A transistor 5 is arranged.

The light emitted from the light emitting diode 4 can illuminate the region of the recording paper 20 corresponding to the preliminary ejection port 3, and the phototransistor 5 can determine the recording state of the region of the recording paper (i.e., whether or not dot recording is being performed or not). ) can be detected.

FIG. 3 shows the detection of the record 1 in this embodiment,
Furthermore, it is a diagram showing a control system for driving the preliminary ejection port 3 based on the result of the detection Llj.

As shown in FIG. 3, the presence or absence of recording dots is determined by comparing the output voltages of the phototransistor 5 with the comparator 8, and the result is input to the control device 10.

On the other hand, the storage device 9 stores the recording information applied to the lowermost ejection port 2 during the previous main scan.

The control device 10 outputs a command to the preliminary ejection port 3 to eject ink droplets according to the recording information processing at a predetermined timing, depending on the result of determining the presence or absence of the recording dot.

Next, the operation of this embodiment will be explained.

FIG. 4(a) shows a pattern to be printed. It is assumed that the pattern is divided into two lines and printed by two main scans. That is, as shown in FIG. 4(b), as the first line, the characters A and B and the upper half of the parentheses are recorded by ink ejection from the ejection port 2, and as the second line, the fourth It is assumed that the letters C and D and the lower half of the parentheses are recorded by ink ejection from the ejection port 2, as shown in FIG.

If the sub-scanning, that is, the paper feed is normal, the correct pattern shown in Figure 4 (a) will be recorded, but if the paper feed is excessive, the parentheses will be printed as shown in Figure 4 (d). This results in records that are not completely connected (equivalent to white stripes in the case of solid black).

In this embodiment, sub-scanning is performed after recording the first line, and then the head unit 1 is moved in the opposite direction to that during recording, and at this time, the light emitting diode 4 is turned on to illuminate the recording paper area corresponding to the preliminary ejection port 3. While illuminating the area, the phototransistor 5 detects the recording state of the area.

When the paper feed is normal, the correct pattern as shown in FIG. The recorded dots are detected.

If the paper feed is excessive, a pattern with white streaks as shown in FIG. Not done.

Therefore, if a recorded dot is detected by the phototransistor 5, it is assumed that one paper feed is normal (although in reality, the paper feed may be too small), and the second
When recording the row, ink is not ejected from the preliminary ejection port 3.

- On the other hand, if no recording dot is detected by the phototransistor 5, when recording the second row,
Ink is ejected from the ejection port 2 and ink droplets are ejected from the preliminary ejection port 3 according to the recording information processing. As a result, dots D are recorded as shown in FIG. 4(e),
There is no occurrence of white streaks as shown in FIG. 4(d).

In addition, the inspection of the recording state using the light emitting diode 4 and the phototransistor 5 does not have to be performed when the head moves backward after the first row, but can be performed at the same time as the recording of the second row, and the correction ejection can also be performed at the same time. be.

FIG. 6 is a diagram showing a second embodiment of the head unit 1 of the inkjet recording apparatus according to the present invention.

In this embodiment, a plurality of sets of preliminary ejection ports 3, light emitting diodes 4, and phototransistors 5 are arranged in the vertical direction, so that it is possible to deal with large width white stripes.

That is, if a recording dot is detected by the lowest phototransistor 5, it is assumed that the paper feed is normal.On the other hand, if a recording dot is not detected by the lowest phototransistor 5, it is determined which number from the bottom. Phototransistor 5
It is determined whether or not a recording dot has been detected until then, and ink droplets are ejected according to the recording information I from the preliminary ejection ports 3 corresponding to consecutive phototransistors for which no recording dot has been detected.

Further, in this embodiment, the light emitting diode 4 and the phototransistor 5 are attached to the main body of the head unit 1 to improve productivity.

FIG. 7 is a diagram showing a third embodiment of a head unit of an inkjet recording apparatus according to the present invention.

In this embodiment, the head unit 1 has cyan, magenta,
It has ejection ports for four colors, yellow and black, and is capable of color recording. A spare spatula 3 is provided for each color discharge n2.

In this embodiment, detection of the recording state and control of ejection of ink droplets from the preliminary ejection ports 3 for each color are performed in the same manner as in the second embodiment.

[Effect of the Invention J As described above, according to the present invention, since the preliminary ejection port and the means for detecting the recorded state 16 corresponding to the preliminary ejection port are provided, the recorded state 16 during sub-scanning is It is possible to correct the appearance of white streaks caused by poor feeding of the medium, thereby improving the recording quality.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of a head unit of an inkjet recording apparatus according to the present invention. FIG. 2 is a diagram showing the configuration of an embodiment of the inkjet storage device of the present invention. FIG. 3 is a diagram showing a control system for the preliminary discharge port of the head unit shown in FIG. 1. FIG. 4 is a diagram showing an example of a recording state on recording paper. FIG. 5 is a diagram showing a state when white streaks are corrected by the head unit of the present invention. FIG. 6 is a diagram showing a second embodiment of the head unit of the present invention. FIG. 7 is a diagram showing a third embodiment of the helad unit 2 of the present invention. Head unit (for normal printing) Ejection port (for white streak correction) Preliminary ejection port Light-emitting element (light-emitting diode) Light-receiving element (phototransistor) Carriage guide axis Comparator Storage device (memory) ■ 0. 12. 18. 20. 21°22. 23. Control device White stripe detection circuit Feed screw Recording paper platen Pulse motor for paper feed Pulse motor for head feed

Claims (2)

[Claims] (1) In an inkjet recording device that performs recording by ejecting ink onto a recording medium from an ejection port of a print head, a spare ejection port is provided adjacent to the ejection port,
An inkjet recording apparatus further comprising means for detecting a recording state of a recording medium area corresponding to the preliminary ejection opening. (2) The inkjet recording apparatus according to claim 1, wherein the recording head discharges ink using thermal energy.