JP2006212874A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recorder capable of improving the yield by compensating positional deviation of a deposited dot due to a step of a chip on a long inkjet head having a connected part and of printing a high quality image. <P>SOLUTION: The steps of at least two or more chips are measured. The printing is carried out by adequately adjusting a distance between the head and a paper sheet according to the step. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printing apparatus such as an ink jet recording apparatus, and more particularly to an ink jet recording apparatus using a long head in which a large number of ink ejection openings are arranged over a relatively wide range, a so-called full multi type head.

  In particular, the present invention relates to an ink jet recording apparatus using a so-called connecting head, which is a full multi type head, which has a plurality of discharge ports and is elongated by arranging a plurality of relatively short nozzle chips with high accuracy. is there.

  Printing devices used in printers, copiers, etc., or printing devices used as output devices such as composite electronic devices and workstations including computers and word processors are used for recording materials such as paper and plastic thin plates based on print information. An image (including characters and symbols) is printed. Such printing apparatuses can be classified into an ink jet type, a wire dot type, a thermal type, a laser beam type, and the like according to a printing method.

  In a so-called serial type printing apparatus that performs a printing operation while performing main scanning in a direction that intersects the conveyance direction (sub-scanning direction) of the recording material, an image is printed by a printing means (print head) that moves along the recording material. By repeating the process of forming and feeding a predetermined amount of paper each time the printing operation for one main scanning is completed, and then performing the printing operation in the next main scanning on the recording material stopped again. Printing is performed on the entire recording material.

  On the other hand, in a line type printing apparatus that involves only the sub-scanning movement in the conveyance direction of the recording material during the printing operation, the recording material is set at a predetermined position and the printing operation for one line is performed continuously. By printing a certain amount of paper, the entire recording material is printed.

  Among the above-described printing apparatuses, an ink jet printing apparatus (ink jet recording apparatus) performs printing by ejecting ink from a print head serving as a printing unit to a recording material, thereby reducing the size of the print head. Is easy, high-definition images can be formed at high speed, so-called plain paper can be printed without the need for special processing, running costs are low, and the non-impact method reduces noise. In addition, there is an advantage that it is easy to adopt a configuration for forming a color image using multicolor inks.

  A line printer using a so-called full multi-type print head in which a large number of inkjet print elements and nozzles (ink discharge ports) are arranged in a direction orthogonal to the recording material conveyance direction is used for image formation. A further increase in speed is possible, and the possibility as a printer for on-demand printing whose needs have been increasing recently has been attracting attention (for example, see Patent Document 1).

  On-demand printing is different from printing in units of several million copies like conventional newspapers and magazines, and printing speeds of 100,000 sheets per hour are not required, but labor saving is desired. Although the full multi-type line printer is greatly inferior in printing speed as compared with a conventional offset printing machine or the like, it is not necessary to make a printing plate, so it can save manpower and is optimal for on-demand printing.

  Now, in such a full multi-type line printer used for on-demand printing, a resolution of 600 × 600 dpi (dots / inch) for a monochromatic printed document such as a text, and a full-color image such as a photograph are used. Is required to print at a high resolution of 1200 × 1200 dpi or more on an A3-sized recording material at 30 pages or more per minute.

On the other hand, there are cases where images taken with a digital camera or the like are output in an L size as in the past, and there are cases where images are printed on small media such as postcards. It can be said that there are very many.
Japanese Patent Application Laid-Open No. 7-241992

  However, in the full multi-type printer, it has been difficult to process the discharge ports and the inkjet print elements provided over the entire width of the printing region without any defects. For example, in a full multi-printer that performs photo-like output on large format paper such as materials output in offices, etc., about 14,000 discharge ports (recording width of about 280 mm) are required to print on A3 paper at 1200 dpi. It is. It is difficult in terms of the manufacturing process to process all the inkjet print elements corresponding to such a large number of discharge ports without any single defect. Even if it can be manufactured, the yield rate is low and the manufacturing cost is enormous.

  For this reason, in a line printer type inkjet recording apparatus using a full multi-type print head, a print head that is elongated by arranging a plurality of relatively inexpensive short chips used in a serial type with high precision, so-called linking. An apparatus realized by using a head has been devised.

However, this connecting head has a problem that the print tends to deteriorate at the connecting portion because of its structure. Specifically, when the chip is displaced, the pitch of adjacent nozzles in the joint portion changes as compared with other nozzle pitches, so that joint stripes are often generated on the printed image.
Several improvement measures have been proposed for such connecting stripes by the connecting head.

  Furthermore, instead of arranging the nozzles at the joints so that the end nozzles of each chip are adjacent to each other, the nozzles at the end of the chip are arranged so as to overlap each other, and when they are printed, they are overlapped. In addition, by ejecting ink from both nozzles, image processing that makes the joint streak inconspicuous is printed, or by changing the amount of ink droplets ejected from the nozzle at the joint portion, the joint portion is changed. A method for making it inconspicuous has been devised.

  Further, even if there is no deviation with respect to the chip arrangement direction, that is, the nozzle arrangement direction, the height of the chip is different for each chip after the bonding or sealing process, and a step or inclination is often generated in the manufacturing process. That is, as with the chip arrangement, arranging the chips with high precision on the head base material (so-called base plate) is also a big problem.

  Naturally, the occurrence of a step or inclination of the chip changes the ink ejection direction and shifts the landing position, thereby deteriorating the image.

  Measures against the chip step in such a manufacturing process include a method of reducing the step by using an array device and a method of reducing the step by using a material that does not easily generate a step in the bonding or sealing process. Proposals for improving the machining accuracy are common.

  Naturally, such an improvement in processing accuracy and selection of materials also lead to an increase in manufacturing cost, so the introduction of the improvement method is determined by the product strategy or the like.

  If a chip step is generated even at one place in the entire long head, the ink ejection direction is changed and the landing position is shifted. As a result, this head becomes defective, and it is very difficult to improve the head yield.

  Accordingly, an object of the present invention is to provide an ink jet recording capable of relieving landing position deviation due to a chip step at a joint portion and improving a yield when manufacturing a long joint head, and capable of high-quality printing. Is to provide a device.

In order to achieve the above object, in the ink jet recording apparatus of the present invention, a short chip comprising a nozzle group in which a plurality of ink jet recording elements (nozzles) are arranged in a direction different from the main scanning direction of the recording material. A long print head arranged in a direction different from the recording material conveyance direction (nozzle row direction) scans the recording material relatively and ejects ink droplets from the nozzles to record an image on the recording material. In an inkjet recording apparatus that performs (printing),
A long print head in which at least one nozzle of the nozzles of adjacent short chips is overlapped (arranged so that ink can be ejected at the same position in the main scanning direction) and the chips are arranged to be long. Because
It is characterized in that at least two or more chips of each chip are measured, and printing is performed by adjusting the optimum head-paper distance according to the steps.

  The ink jet recording apparatus is characterized in that means for measuring a chip level difference of each chip is provided.

  Preferably, a means for adjusting the optimum head-paper distance according to the chip step is provided.

  In the present specification, “print” is not only formed when significant information such as characters and figures is formed, but also manifested so that human beings can perceive visually. Regardless of whether or not, an image, a pattern, a pattern, or the like is widely formed on a recording material, or a medium is processed.

  “Recording material” refers to not only paper used in general ink jet recording apparatuses but also materials that can accept ink ejected by a head, such as cloth, plastic film, and metal plate. And

  Further, the term “ink” should be broadly interpreted in the same way as the definition of “print”, and is applied to the recording material to form images, patterns, patterns, etc., or to process the recording material. Shall refer to the liquid that can be made.

  The present invention eliminates a landing position shift caused by a chip step at a joint portion in a print using a long joint head head in which a plurality of nozzle groups (chips) having a plurality of ink jet recording elements (nozzles) are arranged. It is possible to provide an ink jet recording apparatus capable of improving yield and capable of printing with high image quality.

  Furthermore, by improving the yield of the head, it is possible to provide an ink jet recording apparatus using a long print head at low cost.

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

(First embodiment)
FIG. 1 is a schematic diagram showing an outline of an ink jet recording apparatus according to an embodiment of the present invention. A plurality of long ink jet print heads 1 to 4 constitute a head unit, and each ink jet print head is provided with a plurality of ink ejection openings for ejecting ink. Reference numerals 1, 2, 3, and 4 denote long print heads for ejecting black (K), cyan (C), magenta (M), and yellow (Y) inks, respectively. An ink supply tube (not shown) is connected to the print head, and further, a control signal and the like are sent via a flexible cable (not shown). The recording material 5 such as plain paper, high-quality exclusive paper, OHP sheet, glossy paper, glossy film, postcard, etc. is sandwiched between transport rollers (not shown) and the like in the direction of the arrow (main scanning) as the transport motor is driven. Direction). Heat generating elements (electrical / thermal energy converters) that generate thermal energy for ink ejection are provided in the ink ejection ports (liquid passages) of the inkjet heads 1 to 4 described above. In accordance with the reading timing of a linear encoder (not shown), the heating element is driven based on a recording signal, and ink droplets are ejected and adhered onto the recording material, whereby an image can be printed.

  Reference numeral 6 denotes an adjusting means for adjusting the distance between the head and the recording material in accordance with the step difference of the head. The ink jet print head seals the ink discharge port surface by capping means (not shown) to prevent clogging due to ink sticking or adhesion of foreign matter such as dust due to evaporation of the ink solvent. To do.

  Further, the capping function of the capping unit may be used for idle ejection in which ink is ejected to the cap portion that is separated from the ink ejection port in order to eliminate ejection defects and clogging of the ink ejection port with low recording frequency. Then, the pump (not shown) is operated in a capped state, and ink is sucked from the ink discharge port, which is used for discharge recovery of the discharge port that has caused discharge failure. Further, by disposing a blade and a wiping member (not shown) adjacent to the cap portion, it is possible to clean the ink discharge port forming surface of the inkjet head.

  FIG. 2 is a diagram showing a partial structure of the above-described ink jet print head. In FIG. 2, the inkjet head 21 is schematically configured from a heater board 23 that is a substrate on which a plurality of heaters 22 for heating ink is formed, and a top plate 24 that is placed on the heater board 23. . A plurality of discharge ports 25 are formed in the top plate 24, and a tunnel-like liquid path 26 communicating with the discharge ports 25 is formed behind the discharge ports 25. Each liquid passage 26 is commonly connected to one ink liquid chamber at the rear thereof, and ink is supplied to the ink liquid chamber via an ink supply port, and this ink is supplied from the ink liquid chamber to each liquid passage. 26.

  The heater board 23 and the top plate 24 are assembled so that each heater 22 comes to a position corresponding to each liquid passage 26 and is assembled as shown in FIG.

  Although only four heaters 22 are shown in FIG. 2, the heaters 22 are arranged one by one corresponding to the respective liquid paths 26. When a predetermined drive pulse is supplied to the heater 22 in the assembled state as shown in FIG. 2, the ink on the heater 22 boils to form bubbles, and the ink expands from the discharge port 25 by the volume expansion of the bubbles. Extruded and discharged. The ink jet recording method applicable to the present invention is not limited to the bubble jet (registered trademark) (BJ) method using a heating element (heater) as shown in FIG. 1 and FIG. In the case of a continuous type in which ink droplets are continuously ejected into particles, a charge control type, a divergence control type, etc., and in the case of an on-demand type in which ink droplets are ejected as required, the piezoelectric vibration element machine A pressure control system that ejects ink droplets from an orifice by mechanical vibration is also applicable.

  FIG. 3 is a block diagram showing an example of the configuration of the inkjet recording apparatus control system of the present invention. In FIG. 3, 31 is an image input unit, 32 is an operation unit, 33 is a CPU unit for performing various processes, 34 is a storage medium for storing various data, 34a is information mainly on the type of printing material, and 34b is for printing. Information about the ink to be used, 34c is a print information storage memory for storing information about the environment such as temperature and humidity during printing, and 34d is a group of various control programs. Furthermore, 35 is a RAM, 36 is an image data processing unit, 37 is an image recording unit for outputting an image, and 38 is a bus unit for transferring various data.

  More specifically, 31 is an image input unit for inputting multi-value image data from an image input device such as a scanner or a digital camera, or multi-value image data stored in a hard disk of a personal computer, and 32 is a setting of various parameters. An operation unit 33 having various keys for instructing the start of printing is a CPU that controls the entire recording apparatus in accordance with various programs in the storage medium. A storage medium 34 stores a program for operating the recording apparatus according to a control program and an error processing program. All operations in this embodiment are performed by this program. A ROM, FD, CD-ROM, HD, memory card, magneto-optical disk, or the like can be used as the storage medium 34 for storing the program. Reference numeral 35 denotes a RAM used as a work area for various programs in the storage medium 34, a temporary save area for error processing, and a work area for image processing. The RAM 35 can also copy the various tables in the storage medium 34, change the contents of the tables, and proceed with image processing while referring to the changed tables.

  An image data processing unit 36 quantizes the input multi-valued image data into N-valued image data for each pixel and creates an ejection pattern corresponding to the gradation value “K” indicated by each quantized pixel. It is. That is, after the input multi-value image data is converted to N-value processing, an ejection pattern corresponding to the gradation value “K” is created. For example, when multi-value image data expressed in 8 bits (256 gradations) is input to the image data input unit 31, the image processing unit 36 sets the gradation value of the output image data to 25 (= 24 + 1) values. Need to convert. Here, the multi-valued error diffusion method is used for the K-value processing of the input gradation image data. However, the present invention is not limited to this, and an arbitrary halftone processing method such as an average density storage method or a dither matrix method may be used. Can do. Further, by repeating the above-described K-value conversion processing for all the pixels based on the density information of the image, a binary drive signal for ejection and non-ejection for each pixel for each ink nozzle is formed.

  An image recording unit 37 ejects ink based on the ejection pattern created by the image data processing unit 36 to form a dot image on the printing material, and 38 represents an address signal, data, control signal, etc. in the apparatus. It is a bus line that transmits.

  First, regarding creation of print data, print data using the print head of the present invention can be prepared by a method used in a normal ink jet printer. In this embodiment, the input image is color-separated so as to correspond to each color head, and then the color-separated gray image is binarized by an error diffusion method to prepare print data to be printed by each color print head. did.

  The full multi-type long print head of the present invention will be described in detail, and the present invention will be described in detail.

  Next, a method for measuring and adjusting the head height, which is a characteristic part of the present invention, will be described with reference to FIGS.

  FIG. 4 is a side view schematically showing the arrangement of each chip in the full multi-type long print head according to the present invention.

  A plurality of chips 41 to 44 having a relatively short nozzle group (small number of nozzles) as shown in FIG. 4 are arranged while being shifted in the nozzle row direction (four in FIG. 4), one long nozzle The group unit 45 is configured on a head substrate (base plate) 46, and a full multi-type long print head is configured.

  FIG. 5 shows an example of a schematic view of the head as viewed from the front (in the direction in which the nozzle rows are arranged), and it can be seen that there is a step in the chip during the bonding and sealing process when manufacturing the head. .

  FIG. 6 is a schematic diagram showing how ink is ejected from each chip. FIG. 6A is a front view of the head (in the direction in which the nozzle rows are arranged), and FIG. 6B is a side view of the head (nozzles). It is the figure which showed typically the discharge direction of the ink droplet discharged from each chip | tip when it sees from the direction orthogonal to a row | line | column. As can be seen from the figure, the ink ejection directions of the chips are scattered.

  FIG. 7 is a diagram schematically showing dots formed by ink ejected from each nozzle. The dots are formed in a state where adjacent dots are largely overlapped at the connecting portion of the chips, or in a state where the dot formation position is shifted for each chip.

  When this printed matter was visually observed, the connecting portion was clearly conspicuous, and stripe-like unevenness or moire-like unevenness was visually recognized.

  Next, a description will be given of a method of measuring the chip level difference of the present embodiment and adjusting based on the measurement data.

  FIG. 8 is a schematic diagram for explaining the measurement of the surface level difference of each chip of the head.

  In the figure, reference numerals 41 to 44 denote nozzle group chips, and reference numeral 45 denotes a head unit.

  Reference numeral 46 denotes a head substrate (base plate) provided on 45.

  Reference numeral 47 denotes a displacement sensor that irradiates a laser beam to detect reflected light and measures a chip level difference, and performs measurement while sequentially scanning each chip surface.

  As a result of measuring each chip by the displacement sensor 47, the chips 41 and 44 had a step difference of several tens of μm or more at both ends, and the inclination was confirmed.

  Based on this measurement data, the head is adjusted so that the step and inclination of each chip of the entire head are minimized.

  Specifically, the distance between the head and the recording material is made close so that the step and inclination of the entire head are minimized, and the inclination of the entire head is adjusted to be set to the distance L (FIG. 9).

  In this embodiment, the initial setting value of the distance between the head and the recording material of the printing apparatus main body is a distance M (M> L).

  Printing was performed with the head attached to the printing apparatus main body so as to have the above-described posture and the head-recording material distance L.

  FIG. 10 is a diagram schematically showing dots formed by the ink ejected from each nozzle at this time.

  When this printed matter was visually observed, the connecting portion was not noticeable, and no stripe-like unevenness or moire-like unevenness was observed.

  In the present embodiment, the displacement sensor is not particularly limited to the laser sensor, and any displacement sensor can be used as long as it can measure the step of the chip.

  Further, since the step of each chip of the head is only an example, it is needless to say that it is preferable to set the height and the tilt appropriately according to the tilt of the chip.

(Second embodiment)
Next, a second embodiment, which is another embodiment of the present invention, will be described.

  In the second embodiment, a case in which a chip level difference is measured by providing a measuring unit in a printing apparatus main body, and a method of printing by adjusting the head height and inclination will be described.

  FIG. 11 is a diagram schematically illustrating a head and a measuring unit in the printing apparatus according to the second embodiment. Fig.11 (a) is a front view, FIG.11 (b) is a side view.

  In the figure, reference numerals 41A, 41B,..., 44B denote displacement sensors that measure the distance to each chip.

  FIG. 12 is a block diagram showing an example of the configuration of the control system of this measurement adjustment means. 101 is a chip level difference sensor unit, 102 is a comparison calculation unit for calculating a level difference, 103 is a CPU unit for performing various processes, and 104 is various types. A storage unit for storing measurement data, 105 is a head adjustment unit that adjusts the head based on the chip level difference, 106 is a head height adjustment unit that adjusts the distance between the head and the recording material to be printed, and 107 is a head and print. An inter-recording-material sensor unit that measures the distance from the recording material to be recorded, and 108 is a bus unit that transfers various data.

  More specifically, reference numeral 101 denotes a displacement sensor using a laser or the like, and displacement data is sequentially stored on a recording unit 104 described later. Reference numeral 102 denotes a comparison operation unit that calculates the step difference and inclination of the chip from the displacement data of each chip and calculates an adjustment value for the entire head. Reference numeral 103 denotes a CPU that controls the entire measuring means in accordance with a control program stored in the storage unit. A storage unit 104 stores a program for operating the measurement unit in accordance with a control program or an error processing program, measured displacement data, and the like. Specifically, RAM, FD, HD, a memory card, a magneto-optical disk, etc. can be used. Reference numeral 105 denotes a head adjustment unit that adjusts the entire head to the adjustment value calculated by the comparison calculation unit 102. Reference numeral 106 denotes a head height adjustment unit that adjusts the distance between the head and the recording material according to the recording material to be used. Reference numeral 107 denotes a recording material interval sensor unit for detecting the distance between the head and the recording material at this time.

  Next, the flow of adjustment processing will be described. First, the head is attached to the printing apparatus main body. The distance between both ends of each chip is measured by each displacement sensor 101, and the measurement result is stored in the storage unit 104.

  The CPU 103 instructs the comparison calculation unit 102 to perform calculation processing, calculates a chip step and inclination from the measurement data, and calculates a head adjustment value. The CPU 103 controls the head adjustment unit 105 to move the head to the adjustment value. Specifically, it instructs to change the height of both ends of the head.

  At this stage, the head adjustment is completed, and printing is actually performed on the recording material. The image printed at this time printed a test chart in which the state of each nozzle of the head can be visually determined. At this time, the recording material is fed in the direction of the arrow (main scanning direction) with the driving of a conveyance motor (not shown). The recording material sensor 107 measures the distance between the head and the recording material by means of the recording material sensors 48A and 48B mounted on the head. The measured value is stored in the one-end storage unit 104.

  The CPU 103 performs a comparison calculation process between the measured value of the distance between the recording materials and the standard set value, and when a difference of a certain value or more is detected, causes the head height adjustment unit 106 to perform height adjustment.

  In the present embodiment, since the distance between the head and the recording material is equal to or greater than the initial setting value M and the connecting portion is conspicuous in the visual result of the test chart, the head height adjustment unit adjusts the distance to M. Went.

  FIG. 13 schematically shows the ink ejection state and the ink dot formation state from each chip when printing is performed after the head height adjustment is completed.

  When this printed matter was visually observed, the connecting portion was not noticeable, and no stripe-like unevenness or moire-like unevenness was observed.

  In the two embodiments of the present invention, correction is made for the step and inclination on the head side. However, when the recording material to be used has surface unevenness, naturally the unevenness on the recording material side is measured. Thus, it goes without saying that it can be suitably used by adjusting the distance between the head and the recording material to an optimum value.

  In this case, it is preferable to measure in real time with higher accuracy by attaching more recording material interval sensors 48 for detecting the head-recording material distance.

  Further, in order to facilitate the description in the present embodiment, a method has been described in which the steps of the individual chips are completely different, and at this time the connecting portion is less noticeable as an image, but is not particularly limited. .

  For example, when an optimum value is determined as the distance between the head and the recording material when the level difference is measured, the distance may be obtained by using an average value for reducing the distance. It is more preferable to select the value to be adjusted at this time by actually forming an image and visually judging.

  It can be suitably adapted by setting the length of the print head to be used, the number of chips to be connected, and the number of overlap nozzles to appropriate values.

  Examples of such an ink jet recording method that can be realized relatively easily and at a low cost include, but are not limited to, the following.

  The present invention provides an excellent effect particularly in a recording apparatus using an ink jet recording head that performs recording by forming flying droplets using thermal energy among ink jet recording methods.

  As its typical configuration and principle, for example, those performed using the basic principle disclosed in US Pat. Nos. 4,723,129 and 4,740,796 are preferable. This method can be applied to both the so-called on-demand type and continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or liquid path holding the liquid (ink). By applying at least one drive signal corresponding to the recording information and giving a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, the thermal energy is generated in the electrothermal transducer, and the recording head This is effective because film boiling occurs on the heat acting surface, and as a result, bubbles in the liquid (ink) corresponding to the drive signal can be formed. By the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection opening to form at least one droplet. It is more preferable that the drive signal has a pulse shape, since the bubble growth and contraction is performed immediately and appropriately, and thus it is possible to achieve discharge of a liquid (ink) having particularly excellent responsiveness. As this pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further excellent recording can be performed by employing the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate of the heat acting surface.

  As the configuration of the recording head, in addition to the combination configuration (straight liquid channel or right-angle liquid channel) of the discharge port, the liquid channel, and the electrothermal transducer as disclosed in each of the above-mentioned specifications, the thermal action A configuration using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose a configuration in which the portion is arranged in a bent region, is also included in the present invention.

  In addition, for a plurality of electrothermal transducers, Japanese Patent Application Laid-Open No. Sho 59-123670 that discloses a configuration in which a common slit is used as a discharge portion of the electrothermal transducer or an aperture that absorbs pressure waves of thermal energy is provided. The effect of the present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 59-138461 which discloses a configuration corresponding to the discharge unit. That is, whatever the form of the recording head is, according to the present invention, recording can be performed reliably and efficiently.

  In addition to the full-line type recording head having a length corresponding to the maximum width of the printing material that can be recorded by the recording device, in addition to the serial type as shown in the above example, Integrated with a fixed recording head or a replaceable chip-type recording head that can be electrically connected to the apparatus main body and supplied with ink from the apparatus main body by being attached to the apparatus main body, or the recording head itself. The present invention is also effective when a cartridge type recording head provided with an ink tank is used.

  In addition, it is preferable to add a recording head ejection recovery means, a preliminary auxiliary means, and the like as the configuration of the recording apparatus of the present invention, since the effects of the present invention can be further stabilized. Specifically, heating is performed using a capping unit, a cleaning unit, a pressurizing or suction unit, an electrothermal transducer, a heating element different from this, or a combination thereof. Examples include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.

  Hereinafter, the present invention will be described more specifically with reference to examples.

[Example 1]
As a long print head used in this example, a print head in which four nozzle groups are arranged as shown in FIG. 14 was prepared. In each nozzle group, nozzles are arranged at an interval of 1200 dpi (about 21.2 μm), and each nozzle group uses four chips having 128 nozzles, and has 512 nozzles in total. Further, these four chips are arranged so that two nozzles overlap each other at the connecting portion.

  The nozzles in each chip are divided into four drive blocks for every four nozzles, and the ink droplets are ejected by sequentially driving the blocks 1 to 4.

  FIG. 15 is a schematic view of the head as viewed from the front.

  In the figure, reference numeral 57 denotes a sensor that irradiates a laser beam and detects reflected light to measure a chip step. Specifically, the measurement is performed while irradiating the head base material (base plate) 56 with laser light as a reference value and scanning each chip surface in turn.

  In the figure, the chips 51 to 54 are confirmed to have steps of 50 μm, 80 μm, 50 μm, and 40 μm, respectively, with respect to the reference head substrate (base plate). Further, the chips 51 and 54 are arranged inwardly with an inclination. Based on this measurement data, the head is adjusted so that the step and inclination of each chip of the entire head are minimized.

  Specifically, the distance between the head and the recording material is made close so that the step and inclination of the entire head are minimized, and the inclination of the entire head is adjusted so that the distance becomes 1.1 mm (FIG. 16).

  The initial setting value of the distance between the head and the recording material of the printing apparatus main body in the first embodiment is 1.3 mm. Printing was performed with the head attached to the printing apparatus main body in the above-described posture and the head-recording material distance of 1.1 mm.

  FIG. 17 is a schematic diagram showing an outline of the printing apparatus used in the first embodiment.

  A plurality of long print heads 1 to 4 constitute a head unit, and a plurality of ink discharge ports for discharging ink are arranged in each print head. Reference numerals 1, 2, 3, and 4 denote long print heads for ejecting black (K), cyan (C), magenta (M), and yellow (Y) inks, respectively. An ink supply tube (not shown) is connected to the print head, and further, a control signal and the like are sent via a flexible cable (not shown). Printed material 5 such as plain paper, high-quality exclusive paper, OHP sheet, glossy paper, glossy film, postcard, etc. is sandwiched by a transport roller discharge roller (not shown) and the like (in the main scanning direction) as the transport motor is driven. Direction). A heating element (heater) that generates thermal energy for ink ejection is provided in the ink ejection port (liquid path) of the inkjet head 1 and the like. Along with the reading timing of a linear encoder (not shown), the heater is driven based on the recording signal, and printing is performed by ejecting ink droplets onto the printing material.

  Each ink droplet was driven to be ejected at 5.0 ± 0.5 pl. As the ink containing the color material, a commercially available ink for inkjet printer BJF900 (manufactured by Canon Inc.) was used.

  As a printing material, photo glossy paper dedicated to inkjet (Pro Photo Paper, PR-101: manufactured by Canon Inc.) was prepared.

  The print head and the printing method will be described in more detail. As the driving speed, the ink droplet ejection driving frequency is 8 kHz. As for the amount of ink to be applied, an image in which 5.0 pl dots are 1000% DUTY, 75% DUTY, 50% DUTY, and 25% DUTY, and a photographic image were prepared.

  When printing a recording matrix with a 1200 dpi pixel square at an ejection frequency of 8 kHz, each ejection reference timing is every 125 μsec. Since each chip is driven by being divided into four blocks as described above, the ejection timing of each block is set to be shifted by about 31 μsec (= 125 μsec / 4 blocks).

  Further, as described above, the nozzles that overlap each other are set to discharge alternately from each nozzle (discharge data is distributed so that the discharge ratio is 1: 1).

  Under the set conditions as described above, the prepared image was printed by one scan.

  FIG. 18 is a diagram schematically showing dots formed by the ink ejected from each nozzle at this time.

When this printed matter was visually observed, the connected portions did not stand out in each printed DUTY, and images could be printed with satisfactory image quality without image quality deterioration such as streaky unevenness and moire unevenness.
Similarly, when another photographic image was printed, the connected portion was not recognized, and the image could be printed with satisfactory image quality with no image quality degradation.

[Example 2]
The long print head used in the second embodiment has the same configuration as that used in the first embodiment. The nozzle groups are arranged at intervals of 1200 dpi (about 21.2 μm), and each nozzle group has 128 nozzles. Four chips having the nozzles of 5 are used, and 512 nozzles are provided in total. Further, these four chips are arranged so that two nozzles overlap each other at the connecting portion.

  The nozzles in each chip are divided into four drive blocks for every four nozzles, and the ink droplets are ejected by sequentially driving the blocks 1 to 4.

  FIG. 19 is a schematic view of the print head as viewed from the front. As in the first embodiment, a step and an inclination are generated for each chip.

  A significant difference from the first embodiment is the tilt of the chip. When the step of the chip was measured by the measuring means in the same manner as in Example 1, it was confirmed that they were 50 μm, 60 μm, 50 μm, and 40 μm, and that the chip 51 was inclined outward and the chip 54 was inclined inward.

  Based on this measurement data, the head is adjusted so that the parallelism of each chip of the entire head is the most parallel.

  Specifically, the overall inclination is adjusted so that the parallelism of each chip is averaged over the entire head (FIG. 20).

  This head was attached to the printing apparatus main body so as to have the posture shown in FIG. 20, and the distance between the head and the recording material was set to 1.3 mm which is a general setting value of the printing apparatus.

  Further, as described above, the nozzles that overlap each other are set to discharge alternately from each nozzle (discharge data is distributed so that the discharge ratio is 1: 1).

  Under the set conditions as described above, the prepared image was printed by one scan.

  FIG. 21 is a diagram schematically showing dots formed by the ink ejected from each nozzle at this time.

  When this printed matter was visually observed, in each print DUTY, the connecting portion was not noticeable, and an image could be printed with satisfactory image quality without deterioration in image quality such as streak-like unevenness and moire-like unevenness.

  Similarly, when another photographic image was printed, the connected portion was not recognized, and the image could be printed with satisfactory image quality with no image quality degradation.

[Example 3]
The long print head used in the third embodiment has the same configuration as that used in the first and second embodiments, and the nozzle groups are arranged at intervals of 1200 dpi (about 21.2 μm). Uses four chips with 128 nozzles, for a total of 512 nozzles. Further, these four chips are arranged so that two nozzles overlap each other at the connecting portion.

  The nozzles in each chip are divided into four drive blocks for every four nozzles, and the ink droplets are ejected by sequentially driving the blocks 1 to 4.

  FIG. 22 is a schematic view of the print head as viewed from the front. As in the first and second embodiments, a step and an inclination are generated for each chip.

  The tilt of the chip is different from the first and second embodiments. When the steps of the chip were measured by the measuring means in the same manner as in Examples 1 and 2, they were 50 μm, 60 μm, 50 μm, and 40 μm, and all of the chips 51 to 54 were inclined in the same direction.

  Based on this measurement data, the head is adjusted so that the parallelism of each chip of the entire head is the most parallel.

  Specifically, the overall inclination was adjusted so that the parallelism of each chip was averaged over the entire head, and the level difference between both ends of the head was set to 0.3 mm (FIG. 23).

  This head is attached to the printing apparatus main body so as to have the posture shown in FIG. 23, and the distance between the head and the recording material is set to 1.3 mm which is a general setting value of the printing apparatus.

  At this time, since the step at both ends of the head is 0.3 mm, the head left end is 1.0 mm, the head right end is 1.6 mm, and the average value of the distance between the head and the recording material is 1.3 mm. (Fig. 24).

  Furthermore, as described above, the nozzles that overlap each other are set to discharge alternately from each nozzle (discharge data is distributed so that the discharge ratio is 1: 1).

  Under the set conditions as described above, the prepared image was printed by one scan.

  FIG. 25 is a diagram schematically showing dots formed by the ink ejected from each nozzle at this time.

  When this printed matter was visually observed, in each print DUTY, the connecting portion was not noticeable, and an image could be printed with satisfactory image quality without image quality deterioration such as streak-like unevenness or moire-like unevenness in the connecting portion.

  Similarly, when another photographic image was printed, the connected portion was not recognized, and the image could be printed with satisfactory image quality with no image quality degradation.

[Example 4]
The long print head used in the fourth embodiment has the same configuration as that used in the first, second, and third embodiments, and each nozzle group has nozzles arranged at an interval of 1200 dpi (about 21.2 μm). The nozzle group uses four chips having 128 nozzles, and has 512 nozzles in total. Further, these four chips are arranged so that two nozzles overlap each other at the connecting portion.

  The nozzles in each chip are divided into four drive blocks every four nozzles, and the ink droplets are ejected by sequentially driving the blocks 1 to 4.

  FIG. 26 is a diagram schematically showing the head and measuring means in the printing apparatus used in this embodiment. FIG. 26A is a front view and FIG. 26B is a side view. In the figure, 51A, 51B,... 54B are displacement sensors that measure the distance to each chip.

  As can be seen from FIG. 26, the print head has steps and inclinations for each chip as in the other embodiments.

  The adjustment method will be described below.

  First, when the head is attached to the printing apparatus, measurement is started, and the distance between both ends of each chip is measured by each distance sensor.

  The measurement result is processed by the comparison operation unit, the chip step and inclination are calculated, and the adjustment value of the entire head is calculated.

  The head adjustment unit is operated and moved so that the specified adjustment value is obtained. Specifically, the heights of both ends of the head were changed (FIG. 27).

  At this stage, the head adjustment is completed, and printing is actually performed on the recording material.

  Further, as described above, the nozzles that overlap each other are set to discharge alternately from each nozzle (discharge data is distributed so that the discharge ratio is 1: 1).

  At this time, first, as an image to be printed, a test chart was prepared and printed so that each nozzle state of the head could be visually determined.

  The recording material is fed in the direction of the arrow (main scanning direction) with the driving of a conveyance motor (not shown).

  The distance between the head and the recording material is measured by the recording material sensors 58A and 58B attached to the head. When a comparison calculation process between the measured value and the standard set value was performed, a difference of 0.2 mm was detected, and thus the head height was adjusted.

  Specifically, the entire head was moved 0.2 mm upward, and adjustment was performed so that the distance between the head and the recording material was 1.3 mm, which is an initial setting value (FIG. 28).

  Under the set conditions as described above, the same image as that in the other examples was printed by one scan.

  FIG. 29 schematically shows an ink discharge state from each chip and an ink dot formation state when printing is performed after the head height adjustment is completed.

  When this printed matter was visually observed, in each print DUTY, the connecting portion was not noticeable, and an image could be printed with satisfactory image quality without image quality deterioration such as streak-like unevenness or moire-like unevenness in the connecting portion.

  Similarly, when another photographic image was printed, the connected portion was not recognized, and the image could be printed with satisfactory image quality with no image quality degradation.

1 is a schematic diagram illustrating a configuration of an ink jet recording apparatus according to an embodiment of the present invention. It is a figure which shows typically the structure of a part of print head of the inkjet recording device based on this invention. FIG. 2 is a block diagram illustrating an example of a configuration of a control system of the ink jet recording apparatus according to the embodiment of the present invention. It is the schematic diagram shown about arrangement | positioning of the several nozzle group in the full multi-type long print head in this invention. It is the schematic diagram which showed the outline about arrangement | positioning of the several nozzle group in the full multi type long print head in this invention, and its level | step difference. FIG. 3 is a schematic diagram schematically showing a state when the ejection direction of ink droplets ejected from each chip is viewed from the front and side of the head in the long print head according to the first embodiment of the present invention. It is the schematic diagram which showed the outline about arrangement | positioning of the ink dot discharged from each chip | tip with the elongate print head in 1st embodiment of this invention. It is the schematic diagram which showed the outline about the structure of the means to measure the level | step difference of each chip | tip with the elongate print head in 1st embodiment of this invention. FIG. 4 is a schematic diagram schematically showing a positional relationship that minimizes the step and inclination of the entire head in the long print head according to the first embodiment of the present invention. In the long print head according to the first embodiment of the present invention, the arrangement of the ink dots ejected from each chip when the head-recording material distance is set such that the step and inclination of the entire head are minimized is outlined. It is the schematic diagram which showed. It is a figure which shows typically the state from the front of a head, and a side surface about the elongate head and measuring means in the printing apparatus in 2nd embodiment of this invention. It is a block diagram which shows an example of a structure of the control system of the measurement adjustment means in the printing apparatus in 2nd embodiment of this invention. In the second embodiment of the present invention, a schematic diagram showing an outline of the arrangement of the ink dots ejected from each chip when the distance between the head and the recording material is set such that the step and inclination of the entire head are minimized. It is. It is the schematic diagram shown about arrangement | positioning of the several nozzle group in the full multi type elongate print head in Example 1 of this invention. It is the schematic diagram which showed the outline about the structure of the means to measure the level | step difference of each chip | tip with the elongate print head in Example 1 of this invention. FIG. 5 is a diagram schematically showing a state when the entire head is adjusted so that the distance between the head and the recording material is brought close to the long print head in Embodiment 1 of the present invention so that the step and inclination of the entire head are minimized. is there. 1 is a schematic diagram illustrating a configuration of an inkjet recording apparatus according to Examples 1, 2, and 3 of the present invention. FIG. 3 is a schematic diagram illustrating an outline of an arrangement of ink dots ejected from each chip when the head is attached and adjusted in the long print head according to the first exemplary embodiment of the present invention. It is a schematic diagram which shows typically the state when the level | step difference and inclination of each chip | tip are seen from the front of a head with the elongate print head in Example 2 of this invention. It is a figure which shows typically a state when the whole head is adjusted so that the parallelism for every chip | tip in the whole head may become average in the elongate print head in Example 2 of this invention. FIG. 10 is a schematic diagram illustrating an outline of an arrangement of ink dots ejected from each chip when the head is attached and adjusted in the long print head according to the second exemplary embodiment of the present invention. It is a schematic diagram which shows typically the state when the level | step difference and inclination of each chip | tip are seen from the front of a head with the elongate print head in Example 3 of this invention. It is a figure which shows typically a state when the whole head is adjusted so that the parallelism for every chip | tip in the whole head may become average in the elongate print head in Example 3 of this invention. FIG. 10 is a diagram schematically illustrating an adjustment position when a head, which is a long print head in Example 3 of the present invention and is adjusted so that the parallelism for each chip is averaged over the entire head, is attached to the printing apparatus main body. FIG. 10 is a schematic diagram illustrating an outline of an arrangement of ink dots ejected from each chip when the head is attached and adjusted in the long print head according to the third exemplary embodiment of the present invention. It is a figure which shows typically the state at the time of the long head and measuring means in the printing apparatus in Example 4 of this invention from the front of a head, and a side surface. FIG. 6 schematically shows a state when the entire head is adjusted so that the parallelism of the entire head is averaged from the results measured by the measuring unit in the long print head in the printing apparatus according to the fourth exemplary embodiment of the present invention. FIG. It is a figure which shows typically a state when the distance between head-recording materials is adjusted from the result measured by the measurement means with the elongate print head in the printing apparatus in Example 4 of this invention. FIG. 10 is a schematic diagram illustrating an outline of the arrangement of ink dots ejected from each chip when the head adjustment is completed with the long print head in the printing apparatus according to the fourth exemplary embodiment of the present invention.

Explanation of symbols

1-4 Inkjet (printing) head 5 Recording material 6 Head-recording material distance adjusting means 21 Inkjet head 22 Heater 23 Heater board 24 Top plate 25 Discharge port 26 Liquid path 31 Print data input unit 32 Operation unit 33 CPU
34 Storage medium 34a Printed material information 34b Ink information 34c Environmental information 34d Various control programs 35 RAM
36 Image processing unit 37 Image storage unit 38 Data buses 41 to 44 Chip (nozzle group)
41A to 44B Distance sensor 45 Nozzle group unit 46 Head substrate (base plate)
47 Distance sensor 48A, 48B Distance sensor 51-54 Chip (nozzle group)
51A to 54B Distance sensor 55 Nozzle group unit 56 Head substrate (base plate)
57 Distance sensor 58A, 58B Distance sensor 101 Chip level sensor unit 102 Comparison operation unit 103 CPU
104 Storage unit 105 Head adjustment unit 106 Head height adjustment unit 107 Recording material sensor unit 108 Data bus

Claims (7)

A short chip consisting of a nozzle group in which a plurality of inkjet recording elements (nozzles) are arranged in a direction different from the relative scanning direction of the recording material is arranged in a direction (nozzle row direction) different from the scanning direction of the recording material. In an inkjet recording apparatus that performs image recording (printing) on a recording material by relatively scanning the recording material and ejecting ink droplets from nozzles by using a long print head arranged in a plurality of ways,
An ink jet recording apparatus, wherein printing is performed by adjusting the adjusting means so as to obtain an optimum head-recording material distance according to a chip step of at least two chips among the chips.   2. The ink jet recording apparatus according to claim 1, wherein the long head is adjusted by measuring a step in advance when the head is shipped by a chip step measuring means and a head adjusting means provided, and the adjusted head is placed on the recording apparatus. The inkjet recording apparatus according to claim 1, wherein mounting printing is performed.   3. The ink jet recording apparatus according to claim 2, wherein the head adjusting means adjusts the recording material so that the step of each chip is minimized.   3. The ink jet recording apparatus according to claim 2, wherein the chip level difference adjusting means adjusts the surface of each chip to be parallel to the recording material.   2. The ink jet recording apparatus according to claim 1, wherein means for measuring a chip level difference of each chip and means for adjusting a head-recording material distance are provided, and the chip level difference and inclination are measured on the recording apparatus. An ink jet recording apparatus that measures an inter-distance and prints by adjusting a distance between a head and a recording material according to the measured result.   6. The ink jet recording apparatus according to claim 5, wherein the head adjusting means according to claim 5 adjusts the recording material so that the step of each chip is minimized.   6. An ink jet recording apparatus according to claim 5, wherein the head adjusting means adjusts the surface of each chip to be parallel to the recording material.

Images