JPH022014A - Ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To always perform good recording by mounting a block setting means for dividing a large number of ink emitting orifices of a recording head into a plurality of blocks and differentiating emission recovery operation modes at every blocks. CONSTITUTION:An ink jet recording apparatus has a means for detecting the width of recording paper 17 and, when a recording signal is sent, a cap member 14 is detached from a recording head 13 to open an emitting surface and, when the recording paper 17 is set, the width thereof is detected by said means. Then, the ink emitting orifices present within the width of the recording part among all of ink jetting orifices are discriminated from those not present within said width on the basis of the detection of the width of the recording paper to be used in recording while the ink emitting orifices not present within the paper width perform empty emission toward the ink absorbing body possessed by the cap member 14 present at the position opposed to said orifices to prevent the clogging of the orifices due to the solidification of ink. Next, it is judged whether recording is finished and, when recording is not finished, the above mentioned operation is repeated and, when recording is finished, the cap member 14 is moved and closes the emitting orifice surface to stand by.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an inkjet recording apparatus, and more particularly to an inkjet recording apparatus in which the ejection recovery processing function of a line type recording head is improved.

[Prior art]

An inkjet recording device discharges ink from a plurality of ink discharge ports provided in a recording head based on an image data signal, and produces an ink liquid? This is a device that records by attaching R to recording paper, and is used as a recording device such as a printer or facsimile.

There are two types of inkjet recording devices: a serial type, in which the recording head is mounted on a carriage that moves along the recording paper, and records each line by scanning in the paper width direction; There is a line type that performs recording using a multi-head with arrays of ink ejection ports.

There are two types of multi-heads: a type in which short heads are arranged in a staggered manner, and a fully multi-head type in which ink ejection ports for one line are arranged in a straight line.

In the case of the line type, there is no irregularity in the connection of recorded images due to recording head scanning unlike in the serial type, and there is an advantage that high-speed recording is possible. Also available are yellow, magenta,
Color recording is also possible by arranging a plurality of recording heads with different ink colors such as cyan and black.

FIG. 9 is a perspective view showing the main structure of a line type inkjet recording apparatus. In the figure, the recording paper 17 is conveyed by paper feed rollers 1 installed at a predetermined interval at the upper and lower parts.
5 and paper presser 16, the paper is fed in the direction of the arrow in the figure while its conveyance path is regulated. The line type recording head 13 is arranged at a predetermined interval (for example, 0.05 mm) with respect to the recording paper 17.
5vn) and facing each other. A cap member 14 equipped with an ink absorber is installed at a position facing the line type recording pad 13 across the recording paper 17, and is attached to the recording head as necessary. 3, the ejection port surface of the recording head I3 can be capped.

[Problems to be Solved by the Invention] By the way, in a line type inkjet recording device, as is clear from FIG.
When attempting to record on a paper 17 with a paper width a smaller than , ink is ejected according to the image data in the area a where there is paper in front of the ink ejection port, but ink is ejected in the area a where there is no paper in front of the ink ejection port. Since this is not necessary for recording, ink is not ejected and the ejection port is always open.

As a result, the ink ejection ports tend to become clogged due to solidification of the ink due to evaporation of the ink solvent, adhesion of dust, etc., and when recording on paper #3 whose width is larger than 1 in subsequent recordings, the area There has been a problem in that ejection failure occurs, resulting in low cost, and stable recording cannot be performed.

In addition, in a line type device, unlike a serial type, it is difficult to provide a home position outside the width of the recording paper, that is, at a position adjacent to the recording area, and to move the recording head there to perform an ejection recovery operation.

In other words, in a serial type print head, in order to prevent ink from solidifying due to evaporation of ink solvent at ink ejection ports that are not involved in printing, the print head is moved to the home position when printing is stopped or at predetermined intervals. , a capping operation in which the ejection port surface of the print head is covered with a cap member, a pump means is provided in the ink supply system to pressurize the ink, and the ink is pushed out from the ejection port of the print head into the cap, or the ink is pumped through the cap to the print head. Stable printing is maintained by performing ejection recovery operations such as pumping operations that suck ink from the ejection ports, or dry ejection operations that forcefully eject ink into the cap by applying electrical signals to the print head. There is.

On the other hand, in line type apparatuses, the ejection recovery operation as described above cannot be performed until recording is completed, and therefore there are various difficulties in performing stable recording.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to provide an ink sheet recording apparatus that can always perform good recording.

[Means for Solving the Problems] To achieve this, the present invention provides a print head in which a plurality of ink ejection ports corresponding to one scan of printing is arranged, and a plurality of ink ejection ports in the print head are divided into a plurality of blocks. ,
The present invention is also characterized by comprising block setting means for varying the ejection recovery operation mode in the recording head for each block.

[Function] According to the above configuration, in the line type recording head, it is possible to perform ejection recovery processing only for blocks that are infrequently recorded or blocks that are not used for recording.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

The line-type inkjet recording apparatus according to the first embodiment of the present invention is provided with means for detecting the recording paper width in the line-type inkjet recording apparatus shown in FIG. 9, and according to the process described later in FIG. The ejection recovery operation can be controlled by changing the ejection range according to the recording paper width. Further, the recording paper width is detected by known means. That is, the paper width on the recording paper conveyance path is detected as a difference between the amount of transmitted light or the amount of reflected light using a combination of a light source and a light sensor. Alternatively, the paper width may be detected by operating a mechanical actuator when the paper feed cassette is loaded.

FIG. 1 shows a configuration for controlling the above-described ejection recovery operation. In the figure, 1 is a CPU that executes control of the entire inkjet printing apparatus, IA is a RAM used as a buffer etc. to temporarily store image data to be printed,
Reference numeral 1B is a ROM that stores control procedures and the like for the inkjet recording apparatus, which will be described later in FIG. 2 or 6. Reference numeral 2 denotes a paper width detection circuit as a paper width detection means according to this embodiment, which is disposed at an appropriate location on the recording paper conveyance path. 3 is a capping drive circuit, which controls the movement of the capping member during capping and the ejection recovery operation.
This is done based on a control signal from the PU. Reference numeral 4 denotes a print head drive circuit, which can drive the ejection ports in the print head 13 individually for each block in accordance with a control signal from the CPU. 4' is the recording head 13 in the third embodiment, which will be described later with reference to FIGS. 7 and 8.
A, 13 [1] is a recording head 8-head device that moves 1.

5 corresponds to a second embodiment described later, and the recording head 13
This is a head temperature detection circuit that detects the temperature of the recording head using a temperature sensor 22 for each block of ejection ports.

FIG. 2 is a flowchart showing a control procedure for ejection recovery operation according to the width of recording paper in this embodiment. First, in step 5101, it is determined whether a recording signal has been sent,
If the recording signal is sent, the cap member 14 is completely removed from the recording head 13 in step 5102, and the ejection surface is opened. Next, in step 5103, it is determined whether or not the recording paper 17 is set in the apparatus, and if the recording paper 17 is set, the paper width is detected in step 5104. In step 5105, based on the paper width detection in step 5104, it is determined which portions of all ink ejection ports are within the paper width and which portions are not. Ink ejection ports located within the paper width are used for printing in step 5107. Additionally, for ink ejection ports that are too thin within the width of the paper, dry ejection is performed toward the ink absorber included in the cap member 14 located opposite the ink ejection port to prevent clogging due to ink solidification at the ink ejection ports. do.

Idle ejection is performed at regular intervals during recording. Next, in step 5108, it is determined whether or not the recording has finished. If not, the operations from step 5105 onwards are repeated. When the recording is finished, in step 5109, the cap member 14
, close the ejection port surface, and wait for the next recording.

FIG. 3 is a cross-sectional view of a thermally foamable inkjet recording head according to the 52nd embodiment of the present invention, in which the entire recording can be detected by temperature, and FIGS. 4 and 5 are the recording heads shown in FIG. 3. 3A and 3B are a top view and a front view, respectively, of a line type recording head in which heads are arranged in a staggered manner. In these figures, 20 is a short head having a discharge lobe 218, and the short head 20 includes the following elements. That is, 21 is an ink ejection port, and a plurality of ink ejection ports 2
1, one discharge loblock 21A is formed. 22 is a temperature sensor, 23 is a glass component of the recording head 13, 24 is a substrate, and 25 and 26 are substrates 24.
A heating resistor and an electrode are formed by printing, and 27 is an ink chamber.

With thermally foaming type inkjet recording heads, when the amount of recording is large, the ink temperature in the ink chamber and the ambient temperature of the ink chamber rises due to the heat generated by the heating resistor, and when the amount of recording is very small, these temperatures rise. Almost no change. Therefore, a temperature sensor 22 is provided above the ink liquid chamber 27,
The amount of recording can be determined by detecting the temperature. A thermistor was used as the temperature sensor 22. As shown in FIGS. 4 and 5, short heads 20 provided with such temperature sensors 22 were arranged in a staggered manner to form a line type recording head 13.

FIG. 6 is a flowchart showing an ejection recovery operation according to the print amount when the print head having the above configuration is used. First, in step 5201, it is determined whether or not a recording signal has been sent. If record number 18 has been sent, in step 5202, the cap member 14 is removed from the recording head 13 to open the ejection port surface, and in step 5203 Start recording. During recording, the temperature is detected by the temperature sensor 22 in step 5204, and it is determined in step 5205 whether or not recording has ended. When the recording is finished, in step 5206,
It is determined whether the temperature T detected in step 5204 satisfies TL<T.

Here, TL is the temperature at the top of the ink chamber during non-printing and when the amount of printing is very small, and in this example, T5 is 25
It was set at ℃.

If it is determined in step 5206 that the detected temperature T is below TL, it is determined that the recording amount for the corresponding short head was small, and the process proceeds to step 5208, where after closing the cap member 14, the short head 20 is Only in step 5209, a discharge recovery operation is performed.

As described above, the ejection recovery operation is performed by ink extrusion, pumping such as ink suction, or idle ejection. If T is determined to be larger than TL in step 5206, the discharge port surface is closed by the cap member 14 in step 5207, and the process returns to step 5201.

In addition, in this example, continuous paper (roll paper, foam paper)
When using this method, the recording paper remains in front of the ink jet even after recording is completed. In this case, the cap member 14 cannot be closed and the discharge recovery operation cannot be performed as it is. Therefore, after cutting out the recording paper at the end of the recording,
The cap can be removed by rewinding the leading end of the continuous paper to retract the recording paper from the ink ejection orifice surface, or by retracting the recording head from the recording paper as described in the third embodiment below. The member is closed and a dry discharge recovery operation is performed.

FIG. 7 is a perspective view for explaining the ejection recovery operation according to the width of recording paper in the third embodiment of the present invention, and FIG. 8 is a perspective view for explaining the cap member shown in FIG. 7. It is.

In these figures, reference numerals 21B and 21C refer to an ejection block consisting of a plurality of ejection ports, 138 a main recording head, and 13
B is the auxiliary recording head, 14' is the ejection block 21
Cap member divided corresponding to B and 21G, 1
2 is a waste liquid tube. The main recording head 13A is A4 size (21 (lx 297 mm)) with a vertical width of 1 line (2
The auxiliary recording head 13B is a full multi-head with a discharge lobe block 21B corresponding to 10++ on), and the auxiliary recording head 13B is 1 line (87 mm
) was used as a multi-head having a discharge lobe 21G corresponding to the above.

The combination of the recording head 13A and the auxiliary recording head 13B makes it possible to record a line length corresponding to the length and width of A4 size paper. That is,
The main recording head 138 and the auxiliary recording head 13B are both independently located in the front and rear, and the auxiliary recording head 13B is 8 in the left and right directions.
It was configured to be movable. Cap parts! 4', there are a main recording head 13^ and an auxiliary recording head 1 as shown in FIG.
A recess is formed in the part where the ejection lobe blocks 21B and 21G of 3B contact, and when the ink ejection surface is sealed, the suction pump is connected via the waste liquid tube 12 that communicates with the recess space using the recess. According to
It is now possible to perform ejection recovery operations such as suction or circulation of ink. A valve is provided between the waste liquid tube 12 and the suction pump, so that the suction operations of the main recording head 13A and the auxiliary recording head 13B can be individually controlled. Although silicone rubber is used as the material for the cap member 14', it may be made of a low-hardness elastic body such as resin.

The ejection recovery operation according to the width of the recording paper is performed when the width of the recording paper is AJ.
In the case of MA size, the cap member 14' is attached to the main recording head 13A and the auxiliary recording head 1 as shown in FIG.
3B, and is stored in the lower part of the recording head 1 during ejection recovery operation.
Capping is carried out by the backward movements of 38 and 13B and the upward movement of the cap member 14'. When the width of the recording paper is A4 vertical size, the width of the auxiliary recording head 13B becomes an unnecessary printing area, so the auxiliary recording head 13B moves backward as shown in Figure 7 (B) to accommodate the auxiliary recording head. The cap member 14' is raised to perform capping. Of course, in this case, it is possible to cap the recording head 13.

As a result, ink solidification, dust adhesion, etc., especially at the ink ejection ports corresponding to unnecessary recording areas, are prevented, and it becomes possible to perform a partial ejection recovery operation.

[Effects of the Invention] As is clear from the above description, according to the present invention, in a line type recording head, it is possible to perform ejection recovery processing only for blocks with low recording scalps or blocks that are not used for recording. Become.

As a result, it is possible to prevent clogging of the ink ejection ports due to partial solidification of ink within the print head, adhesion of dust, etc., and stable printing can be performed at all times.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the ejection recovery operation control according to the embodiment of the present invention, FIG. 2 is a flowchart showing the ejection recovery operation in the first embodiment of the invention, and FIG. 3 is the second embodiment of the invention. 4 and 5 are cross-sectional views and front views, respectively, of a line-type recording head in which the recording heads shown in FIG. 3 are arranged in a staggered manner. The figure is a flowchart of the ejection recovery operation in the recording head shown in FIGS. 4 and 5, and FIGS. 7 (8) and (B) are perspective views for explaining the ejection recovery operation in the third embodiment of the present invention. , FIG. 8 is a perspective view for explaining the cap member shown in FIG. 7, and FIG. 9 is a perspective view showing main parts of a line type inkjet recording apparatus. l...CPU IA...IIAM 1B...ROM 2...Paper width detection circuit, 3...Capping drive circuit, 4...Print head drive circuit, 4'...Print head moving device, 5... Head temperature detection circuit, 12... Waste liquid tube, 13... Recording head, 13Δ... Main recording head, 13B... Auxiliary recording head, 14, 14'... Cap member, 15 ...Paper feed roller, 16...Paper presser, 17...Recording paper, 20...Short head, 21...Ink discharge port, 218, 21B, 21G...Discharge block, 22・
...Temperature sensor, 23...Glass, 24...Substrate, 25...Heating resistor, 26...Electrode, 27...Ink liquid chamber. Figure 2 Figure 3 Figure 4 Figure 6 Figure 8 Figure 9

Claims (1)

[Scope of Claims] 1) a print head in which a plurality of ink ejection ports corresponding to one scan of printing are arranged; the plurality of ink ejection ports in the print head are divided into a plurality of blocks; An inkjet recording apparatus comprising: block setting means for varying the ejection recovery operation mode for each block. 2) The inkjet recording apparatus according to claim 1, wherein the block setting means divides the blocks according to the width of recording paper. 3) The inkjet recording apparatus according to claim 1, wherein the division by the block setting means is performed by a recording head configured by the blocks divided in advance. 4) The inkjet recording apparatus according to claim 1, wherein the block setting means divides the blocks according to recording frequency.