JPH05338197A - Ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To always obtain a stable high-grade recording result even when there is quality variation in the recording elements of a recording head or the characteristics of the recording accuracy of the recording head are changed. CONSTITUTION:An ink jet recording apparatus is equipped with a recording sensor unit 9 inspecting the recording accuracy (printing accuracy) of a recording head 6 and a CPU inspects the recording accuracy of the recording head on the basis of the test recording using the recording sensor unit 9 and selects a nozzle good in recording accuracy on the basis of the inspection result to control the selection of the nozzle to be used on the recording head 6. The recording sensor unit 9 has test exclusive paper 12, paper feed mechanisms 10, 11, 13, an illumination lamp 14 and an image sensor 15 and the test exclusive paper 12 is arranged on the extension line of recording paper 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus for recording information such as characters and images by ejecting ink from a plurality of ink ejection openings of a recording head.

[0002]

2. Description of the Related Art Conventionally, in an ink jet recording apparatus, when an ink jet recording head composed of a plurality of ink ejection ports (hereinafter referred to as nozzles) is used to record characters, generally 24 dots (dots), 32 d are used.
The number of nozzles used is switched according to the number of dots of a character font such as ot, 54 dot, or 64 dot. For example, with a 64 nozzle (64 dot) head, 32
When recording a dot font character, 32 nozzles at the upper end (or the lower end) of 64 nozzles are used, and the remaining 32 nozzles are not used. Also, NA
64 for VI-GT (Canon KK) printers
The uppermost (or lowermost) 59 nozzles out of the 5 nozzles are used, and the remaining 5 nozzles are not used. The selection of the nozzle to be used according to the dot configuration of the recording character font is uniquely determined according to the upper end or the lower end of the head regardless of the recording characteristics of the head.

[0003]

However, since the processing of the nozzle holes (ink ejection ports) of the ink jet recording head is usually performed by the laser beam diffused by the prism, the nozzle holes are formed at both ends of the nozzle row as compared with the central portion. It is difficult to obtain the processing accuracy of (3), and therefore the recording quality of the head tends to vary. Therefore, in the case of recording by selecting the used nozzle by uniquely aligning the upper end (or the lower end) as described above, the quality of the nozzle processing accuracy at both ends of the nozzle row directly affects the recording quality (also referred to as the printing quality). become.

Particularly, in the case of a cartridge type head in which a head having a nozzle row and an ink tank are integrated, the head is also replaced at the same time when the ink runs out. There is a problem that the recording quality is changed every time it is performed. For example, 32 with a 64 dot head
When printing the letter "H" of the alphabet with the dot font, even if the head has the recording characteristics shown in the central portion of FIG. 6, it is unconditionally 32 nozzles from the upper end of the head as in the above-described conventional example. 6, the recording result is that the upper part of the ruled line of the character "H" is bent to the right as shown on the left side of FIG. The current situation is that effective measures have not been taken on the printer body side for the above problems.

In view of the above points, an object of the present invention is to always provide a stable and high quality even if the recording elements of the recording head have variations in quality or the characteristics of the recording accuracy of the recording head change. An object of the present invention is to provide an ink jet recording apparatus that can obtain the recording result of 1.

[0006]

In order to achieve the above object, the present invention provides a recording head having a plurality of ink ejection ports, a detecting means for detecting the recording characteristics of the recording head, and a detecting means for detecting the recording characteristics. And a selection means for selecting a series of ink ejection ports to be used from all the ink ejection ports based on the recording characteristics.

As one form thereof, the present invention provides a control means for variably controlling the feed offset amount of the recording material according to the positions of the series of ink ejection ports to be used, which are selected by the selection means. It can further be characterized by having.

As another aspect of the present invention, the detection means may include an image sensor for reading a recording result of test recording using the all-ink ejection ports.

As another aspect of the present invention, the selection means may select the ink ejection port according to the number of dots of a recording character font.

Further, in another aspect of the present invention, the recording head serves as an element for generating energy for ejecting ink, and an electric heat for applying heat energy for causing film boiling of the ink. It can be characterized by having a converter.

[0011]

According to the present invention, means for inspecting the recording accuracy (also referred to as printing accuracy) of the recording head is provided and the nozzles used in the recording head are selected and controlled based on the inspection result. Even if there are variations in the quality of recording elements, etc., or even if the characteristics of the recording accuracy of the recording head change, so-called ruled line bending due to the variation in the recording accuracy of the nozzles at both ends of the head can be eliminated, and it is always stable. It is possible to obtain a high-quality recording result.

[0012]

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

FIG. 1 shows the mechanical structure of the periphery of a recording head of an ink jet recording apparatus according to an embodiment of the present invention as viewed from above. The rotation torque of the stepping motor 1 is transmitted to the timing belt 3 via the gear 2, and the carriages 4 fixed to both ends of the loop belt 3 reciprocate left and right in the horizontal direction 23 of the arrow according to the step drive of the motor 1. Moving. On the carriage 4, a cartridge-type inkjet head (also referred to as an inkjet cartridge) in which a recording head unit 6 including 64 ink ejection ports (nozzles) and an ink ejection heater and an ink tank 5 are integrally configured. 7 is installed. Belt 3
A cleaning unit 8 for periodically removing the clogging of the nozzle is disposed at a position 20 on one side. This position 2
0 is a position where the cleaning unit 8 cleans the head 7, and is also a reference position when the position of the head 8 is calculated from the number of steps of the motor 1.

The recording sensor unit 9 is arranged at the head position 21 when performing test recording on the surface of the test recording sheet, and the test recording sheet 1 having a relatively high ink transmittance.
2. Pins (posts) 13 for keeping the test recording surface of the test recording sheet horizontal, an image sensor 15 for reading the test recording result from the back side, a lamp 14 for irradiating the reading surface, and a read position adjustment by the image sensor 15. And test record form 12 for the next test record
It is composed of a gear 11 for feeding the paper and a stepping motor 10 for rotationally driving the gear.

A sheet 16 to be recorded (printed) by the head 7 in accordance with a command and recording data sent from a host device (not shown) is wound around a platen roller 17, and a step motor 19 is rotated by a gear 18. By being transmitted to the platen roller 17, the paper 16 is fed for each line recording. The ink landing surface of the test recording paper 12 is located on the extension line of the paper 16. Position 22 is the head position at the leftmost end of recording.

FIG. 2 shows a schematic circuit configuration of the control system of the embodiment of the present invention shown in FIG. The carriage system centering on the stepping motor 1, the cleaning system 8, the line feed system centering on the stepping motor 19, the head system 6, and the recording sensor unit 9 are an 8-bit CPU (central processing unit) in the main body of the recording apparatus via a bus. Processor 24).

The flowchart of FIG. 3 is based on the CPU 24 of FIG.
6 shows a procedure of a control operation according to the present invention. This procedure is stored in advance in the form of a program in the internal ROM of the CPU 24.

First, at the reference position 20 of the head 6, the cleaning unit 8 periodically removes the nozzle clogging (step S1). After this cleaning, the carriage driving stepping motor 1 (hereinafter referred to as CR motor 1) is slewed up to the step speed (rotation speed) at the time of recording, and then rotated at a constant recording speed.
At this time, the head 6 also accelerates and moves rightward as the CR motor 1 goes through, and when the CR motor 1 becomes a constant speed, the head 6 also becomes recordable. The position of the head 6 is C
The CPU 24 is always controlling based on the number of steps of the R motor 1 (step S2).

When the head 6 reaches the position 21 in FIG. 1,
Ink is ejected from all the nozzles of the head 6 toward the paper surface of the test recording paper 12 (step S3). On the other hand, C
The R motor 1 stops after slewing down, and then performs reverse slewing up to perform slewing up, constant speed, and slewing down in sequence, and when the head 6 returns to the reference position 20, it enters a rest state (step S4).

Here, as shown by reference numeral 41 in FIG. 4, the head 6 is composed of a group of 8 blocks, with 8 nozzles as one block, and the ink ejected from a total of 64 nozzles of the test recording paper 12 is ejected. Reference numeral 42 in FIG.
If the image is landed as shown in FIG. 4, the recording result viewed from the image sensor 15 is reversed as shown by reference numeral 43 in FIG. In this way, the ink that has landed permeates the transparent test recording sheet 12 and forms an image as indicated by reference numeral 43 in FIG. 4 on the image sensor side. Reference numeral 44 is a read line of the image sensor 15. The case where the recording result as shown by reference numeral 43 is obtained is a case where the nozzle blocks 1 and 2 of the head 6 have a problem (defect).

The image sensor 15 is composed of sensor cells of 8 dots × 8 blocks corresponding to the head 6 of 8 × 8 blocks, and performs temporary reading at the reading position of reference numeral 44 in FIG. 4 (step S5). Here, since the head 6 ejects while moving, it is taken into consideration that the ink landing position is slightly shifted to the right of the ink ejection position. Then, the test recording paper 12 is read by the image sensor 15 while being shifted in the direction of the arrow 45 in FIG. 4 by the test recording paper feed systems 10 and 11 having higher resolution than the carriage system, and 8 dots × 8 blocks The paper feed is stopped at the position where the read density is maximum (step S
6).

1'-8 of the image sensor 15 shown in FIG.
Since the block'corresponds to the nozzle blocks 1 to 8 of the head 6, the CPU 24 uses the read density of each block (1 'to 8') of the image sensor 15 as the recording accuracy of each nozzle block of the head 6 in the internal memory ( It is stored in (not shown) (step S7). Subsequently, the CPU 24 determines the character font (24dot, 32dot) based on the stored data.
For each t, 56 dot, 64 dot, etc., the nozzle block row with the highest printing accuracy (that is, the nozzle block row corresponding to the reading block row with the highest reading density) is selected, and a table as shown in FIG. 5 is created. (Step S8). The arrow in FIG. 5 indicates the usage range of the nozzle block row with high recording accuracy selected for each character font.

Since the line feed amount (paper feed amount) differs depending on the number of dots of the character font, the CPU 24 determines the upper end reference (or the lower end) of the nozzle block row having the highest recording accuracy selected according to the dots of the character font. The offset value (see FIG. 5) of the line feed (paper feed) compared with the reference) is transmitted to the host (step S9).
When the CPU 24 receives the character font selection command and the print data from the host (step 10), the data is appropriately shifted based on the values in the above table (FIG. 5) and transferred to the nozzle block buffer corresponding to the font. Yes (step S11). For example, when recording a 32 dot font with a head having a recording characteristic indicated by reference numeral 42 in FIG. 4, the CPU 24 stores data in the buffer areas of the nozzle blocks 1, 2, 7, and 8 including the nozzle block having the recording accuracy problem. 00h (no printing) is set, and the print data from the host is transferred to the buffer areas of the remaining blocks of 3, 4, 5, and 6 with good print accuracy.

The head 6, which has been resting at the position of reference numeral 20 in FIG. 1, maintains the carriage speed during recording by the constant speed rotation from the slew-up in the forward direction of the CR motor 1 under the control of the CPU 24. To reach the recording leftmost position 22 (step S12). At the same time, the CPU 24 heats the heater portion of the head 6 in accordance with the data transferred to the buffer in the above step S11, and ejects ink from the nozzle (step S13).

If the cleaning process is not performed again, steps S10 to S described above are performed until one line is recorded.
The process of 13 is repeated (step S14). When the cleaning process is performed, the recording characteristics of the nozzle block may also change, so that the above steps S1 to S are performed again.
9 is executed to create a table by test recording (test printing).

According to the above sequence (processing procedure),
The letter “H” in the alphabet is 32dot, 48do
FIG. 6 shows a comparison between the recording result of the present embodiment and the recording result of the conventional example when recording is performed with each font of t. As shown in the figure, in this embodiment, since the nozzle block having good recording accuracy is selected and used based on the inspection result of the recording accuracy,
The ruled line bending at the upper part of the character due to the recording characteristics of the nozzle is greatly improved in this embodiment.

(Other Embodiments) In the above-described embodiment of the present invention, in the information processing for grasping the recording characteristics of the nozzles, as an example, a control table as shown in FIG. However, the present invention is not limited to this, and it is of course possible to perform shift control for selective use for each nozzle by performing processing for each nozzle.

Further, in the above-mentioned embodiment, the test recording result recorded on the dedicated test paper is read from the back surface of the test paper. The test recording result recorded on the recording paper may be read from the surface of the recording paper by this image sensor.

In the above embodiment, the printer main body C is used.
In order to avoid the PU processing from becoming complicated, the line feed offset value for each font is sent to the host side, and the host side controls the line feed amount. C in
You may make it control directly by PU.

Further, by reading the test result as described above, it is possible to detect not only the recording accuracy but also the ejection failure of the ink for each nozzle, which makes it necessary to replace the ink cartridge. Can be notified to the user.

(Others) The present invention is particularly provided with means for generating thermal energy as energy used for ejecting ink (for example, an electrothermal converter or a laser beam) even in the ink jet recording system. The present invention provides excellent effects in a recording head and a recording apparatus of the type in which the thermal energy causes a change in ink state. This is because such a system can achieve high density recording and high definition recording.

Regarding the typical structure and principle thereof, see, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740.
What is done using the basic principles disclosed in 796 is preferred. This method is a so-called on-demand type,
It can be applied to any of the continuous type, but especially in the case of the on-demand type, it can be applied to the sheet holding the liquid (ink) or the electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recorded information and giving a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal converter, and film boiling is caused on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal as a result
This is effective because bubbles can be formed inside. Due to the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection openings to form at least one droplet. It is more preferable to make this drive signal into a pulse shape, because the bubble growth and contraction are immediately and appropriately performed, so that the ejection of the liquid (ink) with excellent responsiveness can be achieved. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the ejection port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned respective specifications. U.S. Pat. No. 4,558,333, U.S. Pat. No. 44, which discloses a configuration in which a heat acting portion is arranged in a bending region.
The configuration using the specification of No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration corresponding to the ejection portion is disclosed in Japanese Patent Laid-Open No. 59-138461. That is, according to the present invention, recording can be surely and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full line type recording head having a length corresponding to the maximum width of a recording medium which can be recorded by the recording apparatus. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads or a configuration as one recording head integrally formed.

In addition, even in the case of the serial type as in the above example, the recording head fixed to the main body of the apparatus or the electrical connection to the main body of the apparatus and the ink from the main body of the apparatus by being mounted on the main body of the apparatus. The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is integrally provided in the recording head itself is used.

Further, as the constitution of the recording apparatus of the present invention, it is preferable to add ejection recovery means of the recording head, preliminary auxiliary means, etc. because the effects of the present invention can be further stabilized. Specifically, heating is performed by using a capping means, a cleaning means, a pressure or suction means for the recording head, an electrothermal converter or a heating element other than this, or a combination thereof. Examples thereof include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.

Regarding the type and number of recording heads to be mounted, for example, only one is provided corresponding to a single color ink, or a plurality of inks having different recording colors and densities are supported. A plurality of pieces may be provided. That is, for example, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but may be either integrally formed of the recording heads or a combination of a plurality of them. The present invention is also very effective for an apparatus provided with at least one of full-color recording modes by color mixing.

In addition, in the above-described embodiments of the present invention, the ink is described as a liquid, but an ink that solidifies at room temperature or lower and that softens or liquefies at room temperature may be used. Or, in the inkjet method, it is common to adjust the temperature of the ink itself within the range of 30 ° C. or higher and 70 ° C. or lower to control the temperature so that the viscosity of the ink is within the stable ejection range. At times, a liquid ink may be used. In addition, the temperature rise due to thermal energy is positively prevented by using it as the energy for changing the state of the ink from the solid state to the liquid state, or in order to prevent the evaporation of the ink, it is solidified and heated in a standing state. You may use the ink liquefied by. In any case, by applying heat energy such as ink that is liquefied by applying heat energy according to the recording signal and liquid ink is ejected, or that begins to solidify when it reaches the recording medium. The present invention can be applied to the case where an ink having a property of being liquefied for the first time is used. In this case, the ink is
JP 54-56847 A or JP 60-7.
As described in Japanese Patent No. 1260, it may be configured to face the electrothermal converter in a state of being held as a liquid or a solid in the concave portion or the through hole of the porous sheet. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as the form of the ink jet recording apparatus of the present invention, besides the one used as an image output terminal of information processing equipment such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function It may be in a form or the like.

[0040]

As described above, according to the present invention, means for inspecting the recording accuracy (also referred to as the printing accuracy) of the recording head is provided, and the selection control of the nozzle used in the recording head is performed based on the inspection result. Therefore, even if there are variations in quality of the recording elements of the recording head or the characteristics of the recording accuracy of the recording head change, stable and high-quality recording results can always be obtained. effective.

[Brief description of drawings]

FIG. 1 is a plan view showing a mechanical configuration of an inkjet recording apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic circuit configuration of a control system of the embodiment apparatus of FIG.

FIG. 3 is a block diagram showing a procedure of control operation according to the embodiment of the present invention.

FIG. 4 is a diagram showing a correspondence relationship between a nozzle block of a recording head and a reading block of an image sensor during a test recording inspection in an embodiment of the present invention.

FIG. 5 is a diagram showing an example of a used nozzle block table for each font in the embodiment of the present invention.

FIG. 6 is a diagram showing an example of a recording result of an example of the present invention and an example of a recording result of a conventional example when the recording accuracy of a recording head varies.

[Explanation of symbols]

1 Carriage Driving Stepping Motor (CR Motor) 4 Carriage 5 Ink Tank 6 Head 7 Inkjet Head (Inkjet Cartridge) 8 Cleaning Unit 9 Recording Sensor Unit 10 Test Recording Paper Feed Stepping Motor 12 Test Recording Paper 14 Lamp 15 Image Sensor 16 Recording Paper 17 Platen Roller 19 Line Feed Paper Feed Stepping Motor 24 CPU 41 Nozzle Group (1 Block) 42 Recorded Image 43 Image Sensor Read Image 44 Read Line 45 Paper Feed Direction for Test Recording

Claims (5)

[Claims] 1. A recording head having a plurality of ink ejection ports, a detection unit for detecting the recording characteristic of the recording head, and based on the recording characteristic detected by the detection unit, from all ink ejection ports An inkjet recording apparatus, comprising: a selection unit that selects a series of ink ejection ports to be used. 2. A control means for variably controlling the feed offset amount of the recording material according to the position of the series of ink ejection openings to be used selected by the selection means. 1. The inkjet recording device according to 1. 3. The ink jet recording apparatus according to claim 1, wherein the detection unit has an image sensor that reads a recording result of test recording using the all ink ejection ports. 4. The ink jet recording apparatus according to claim 1, wherein the selection unit selects the ink ejection port according to the number of dots of a recording character font. 5. The recording head has an electrothermal converter for acting thermal energy that causes film boiling of the ink, as an element that generates energy for ejecting ink. Item 5. The inkjet recording device according to items 1 to 4.