JPH01127360A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To prevent certainly recording quality from deterioration and to achieve high speed of a recording process, by a method wherein an ink collection member is established within an operation range in a main scan direction of a head and besides, ink is discharged just before recording operation in the main scan direction. CONSTITUTION:A head 2 is moved, for instance, at a speed of 0.45m/s in a main scan direction, and ink is sprayed at a min. pitch of 0.15mm. Further, when an effective length in the main scan direction of ink collectors 21, 22 is taken as 1.5mm, the head can be made to pass the ink collectors 21, 22 while, for instance, ink for 10 dots is being sprayed at a drive period of 3kHz from each nozzle. Further, for judging whether the head 2 is passing a position of the ink collector 21 or 22, a pattern of, for instance, a linear encoder 5 is detected with a photosensor 4, and the judgement can be performed by counting a slit of the linear encoder 5. That is, a position of each nozzle is preferably calculated with a CPU from a pitch in the main scan direction of the nozzle in the head 2 and from a distance where the head 2 is moved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inkjet recording device, and in particular,
The present invention relates to an on-demand type inkjet recording apparatus that ejects ink onto a recording medium only when forming images such as figures.

[Prior Art] FIG. 5 shows an example of this type of conventional inkjet printer.

Here, l is a platen that conveys the recording medium in the sub-scanning direction according to the drive of the line feed motor and also regulates the recording surface. Reference numeral 2 denotes an inkjet recording head that moves back and forth in the direction shown by arrow S in the figure (main scanning direction) in accordance with the drive of the carriage motor 8, and performs recording by ejecting ink onto the recording medium in the process. A printer capable of recording has, for example, yellow, magenta, cyan, and black nozzle groups corresponding to ink colors. Reference numeral 3 denotes a cap member disposed facing the head 2 outside the recording range of the head 2, for example at the home position, and moves in the f direction in the figure in response to the drive of the cap motor 6 when the printer is not in use. It is then bonded to the head 2 to protect it.

A photosensor 4 moves in the S direction together with the head 2, and detects the moving position of the head 2 in cooperation with a linear encoder 5 arranged parallel to the S direction.

Further, 9 is a paper sensor for detecting a recording medium, 10 is a cap sensor for detecting the position of the cap 3, and 11 is a home position sensor for detecting the positioning of the head 2 at the home position.

In such a conventional inkjet printer, the recording paper is fed in the sub-scanning direction by the platen 1 in accordance with the drive of the line feed motor, and when the paper sensor 9 detects the paper, printing is started. At this time, first, the cap motor 6 operates to remove the cap 3 from the head 2. When the cap sensor 10 detects this, the carriage motor 8 operates, and the head 2 moves in the main scanning direction S. The head position is detected through cooperation between the sensor 4 and the encoder 5, and the head 2 ejects ink in accordance with the ink ejection timing signal. This ink ejection timing signal is also used as a constant speed traveling control signal (FG signal) for the carriage motor 8.

[Problems to be Solved by the Invention] In such an inkjet recording device, the head 2
is provided with a large number of nozzles, and whether or not all the nozzles are used during recording is uncertain depending on the shape and color of the image to be formed. Rather, cover it up if either nozzle is left unused.

By the way, one of the problems that needs to be solved with on-demand type inkjet recording devices is that the nozzles tend to clog if they are not used for a long time, or even if the nozzles do not clog, they suddenly clog after a long period of non-use. If ink is used, normal ejection may not be performed due to increased viscosity of the ink, resulting in a decrease in recording quality.

Therefore, as in the invention disclosed in Japanese Patent Publication No. 52-2780, an ink collecting device is provided at an appropriate position of the device, and a timer is started during printing, so that when the non-recording state exceeds a set time, the head There is one in which the ink is moved and the ink is ejected from all nozzles toward the ink collection device.

However, in order to improve the recording quality, it is most desirable to use the nozzle all the time, and therefore the above operation needs to be performed frequently.

On the other hand, there is a strong demand for higher recording speeds for recording apparatuses, and for this purpose, it is desirable to minimize the time required for operations other than recording operations during recording processing. Therefore, in a device that performs the ejection operation using a timer as described above, the original recording operation is interrupted each time.
It is hard to say that it can meet the demand for higher speeds.

[Means for Solving the Problems] The present invention solves the conventional problems, and provides an inkjet that can reliably prevent deterioration in recording quality caused by nozzle clogging, and can increase recording processing speed. The purpose is to provide a recording device.

Therefore, the present invention provides an on-demand inkjet recording device that performs main scanning and sub-scanning in connection with a recording operation, which includes a head that ejects ink and an ink collector provided within the operating range of the head in the main scanning direction. The apparatus is characterized by comprising a member and a means for ejecting ink from the head toward the ink collecting member immediately before performing a recording operation in the main scanning direction.

[Function] That is, in the present invention, the ink collecting member is provided within the operating range of the head in the main scanning direction, and the ink is ejected immediately before the recording operation in the main scanning direction, so the time required for recording processing is lengthened. This also prevents clogging of the head and the like.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the invention. Here, for each part that can be constructed in the same manner as in FIG. 5, the same parts are labeled as corresponding parts. In this example, ink collecting sections (ink collectors) 21 and 22 are provided on both sides of the platen 1 within a range (printing range) that the print head 2 always passes during reciprocating motion during printing.
This is provided.

These ink collectors are made of, for example, a liquid-absorbing porous material and can absorb a large amount of ink.

FIG. 2 shows an example of the configuration of the control, etc. of the apparatus shown in FIG. Here, 13 is a CP port in the form of a microcomputer,
It has a ROM 13^, and controls each part according to, for example, the procedure shown in the third figure stored therein. 12 is a power switch,
This is a group of switches such as a command switch to start recording, an online switch, etc.

Reference numeral 14 denotes a forward/reverse reversing circuit that switches between forward and reverse rotation of the carriage motor 8 and moves the head 2 in the S direction by driving it in accordance with an FG signal from a position detection section 24 consisting of a linear encoder 5 and a photosensor 4. can be,
When the carriage motor 8 is configured with a DC motor, D
Contains C servo circuit.

15 is a line feed motor drive circuit that drives the line feed motor 7 to transport the paper.

Reference numeral 16 is a source of image information such as characters, figures, etc., and is, for example, a host device for a recording device. A head driver 17 drives the ejection energy generating elements arranged in each nozzle of the head 2. Further, 18 is a group of various sensors such as the paper sensor 9 and the cap sensor 8.

FIG. 3 shows an example of the recording processing procedure according to this embodiment. In this example, the basic recording operation is the same as before, but
During the reciprocating printing operation in the main scanning direction S, the ink collector 2 immediately before the nozzles of the head 2 eject ink for printing.
1 or 22, all nozzles of the head 2 are made to eject toward the ink collector at this time.

When this procedure starts, first, in step S1, the cap 3 is removed from the head 2, and then, in step S3, the head 2 is moved to the right in FIG. It is detected whether or not the position has been reached, and if the determination is affirmative, ink is ejected from all nozzles at that position, and then, in step S9, recording processing in the forward motion is executed.

When this recording process is completed and the head 2 reaches the right end of the operating range, the head 2 is moved to the left (return operation) in step S13, and steps similar to steps 55, 57 and S9 are performed for the return operation. 515, 517 and 519
After passing through the process, the process returns to step S3 to perform the process in the next forward motion.

In such processing, the head 2 is moved in the main scanning direction to 0.
Move at a speed of 45m/s, minimum pitch 0.15LI
The ink is ejected at I11, and the effective length of the ink collectors 21 and 22 in the main scanning direction is 1.5 mm.
For example, while ejecting lθ dots of ink from each nozzle at a driving cycle of 3 KHz, the ink collector 2
1 and 22 can be passed.

Further, it can be determined whether the head 2 is passing the position of the ink collector 21 or 22 by, for example, detecting the pattern of the linear encoder 5 with the photosensor 4 and counting the slits of the linear encoder 5. . That is, the position of each nozzle is calculated from the pitch of the nozzles in the head 2 in the main scanning direction and the distance traveled by the head 2.
What is necessary is to calculate pH13. Alternatively, a photo sensor or the like for detecting the head 2 may be separately provided near the locations where the ink collectors 21 and 22 are arranged, and ink may be ejected in response to this detection. Alternatively, in a recording apparatus that uses a pulse motor instead of the carriage motor 8, the position control of the head 2 can be managed by drive pulses, so the ejection process may be performed by counting these pulses.

In this embodiment, the nozzles behind the recording range in the main scanning direction, that is, the nozzles on the right when head 2 is on the left in FIG. 1, and the nozzles on the left when head 2 is on the right, ink. If it is moved to a position that reaches the collector 21 or 22, the range of reciprocating movement will be expanded, which may cause wasted time. Therefore, only the nozzles on the front half or more in the moving direction may be driven to eject ink to the ink collector.

As a result, the movement range of the head 2 in the main scanning direction can be minimized, and by performing this ejection back and forth, all nozzles are always used in one round trip, so it is virtually impossible to Usage time can be shortened and ink ejection characteristics do not deteriorate.

Furthermore, in the above embodiment, ink collectors are provided on both sides of the platen 1 in consideration of the case where reciprocating printing is performed, but in an apparatus that performs reciprocating printing on either side, only a single ink collector is provided. It may be provided.

Next, FIG. 4 shows another embodiment of the present invention.

In this embodiment, the main scanning direction and backward scanning direction in the first embodiment are switched, and the platen 31 rotates at a constant speed in the direction of the arrow to perform main scanning.

The head 32 periodically scans the recording medium surface in a direction perpendicular to the drawing. The ink collector 33 is provided at a position on the platen 31 where the recording paper 34 cannot exist, and the head 32
When each nozzle in the ink collector 33 faces the ink collector 33, ink is ejected. At the same time, the head 32 moves one pitch in the backward scanning direction. Subsequently, one line is recorded in the main scanning direction while the platen 31 rotates once while the head 32 remains stationary.

Even with this type of recording apparatus, the same effects as in the first embodiment can be obtained.

In this example, the nozzle group may be provided along the length of the recording paper in a direction perpendicular to FIG. 4. At this time, there is no need to feed the head, and the apparatus takes the form of a so-called line printer.

According to each of the embodiments described above, in an on-demand inkjet printing apparatus that performs printing in conjunction with main scanning and backward scanning operations, at least half of all nozzles are directed toward the ink collector immediately before printing during main scanning. Since the ink is ejected from the above nozzles, it is possible to record images of higher quality without increasing the recording processing time.

[Effects of the Invention] As explained above, according to the present invention, clogging of nozzles can be prevented, so that recording quality can be prevented from deteriorating.
Furthermore, an excellent effect can be obtained in that the recording processing time can be shortened.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing one embodiment of the present invention, and Fig. 2 is a plan view showing an embodiment of the present invention.
FIG. 3 is a block diagram showing a configuration example of a control system of the illustrated device; FIG. 3 is a diagram of the device shown in FIGS. 1 and 2; FIG. 4 is a side view showing another embodiment of the present invention; FIG. 1 is a plan view showing an example of an inkjet recording apparatus. 1.31...Platen, 2.32...Head, 3...Cap, 4...Photo sensor, 5...Linear encoder, 6...Cap motor, 7...Line feed motor, 8 ... Carriage motor, 9... Paper sensor, lO... Cap sensor, 11... Home position sensor, 13-CPU. 13^...-ROM. 14-... Forward/reverse inversion circuit, 15... Line feed motor drive circuit, 21.22
．． 33...Ink collector. Figure 3 Figure 4

Claims (1)

[Claims] An on-demand inkjet recording device that performs main scanning and sub-scanning in connection with a recording operation, comprising: a head that discharges ink; and an ink provided within the operating range of the head in the main scanning direction. An inkjet recording apparatus comprising: a collection member; and means for ejecting ink from the head toward the ink collection member immediately before performing a recording operation in the main scanning direction.