JP2007203592A - Image forming apparatus and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect changing quality of printing, to optimize image recording conditions on real time, to reduce cost, and to improve productivity. <P>SOLUTION: An image forming apparatus has a plurality of printing units 12-1 to 12-4 arranged along a conveying path for a recording medium and having liquid delivering heads and fixing means, a detecting area setting means for setting a plurality of detecting areas in an image on the recording medium, a first delivering and fixing condition setting means which can set a plurality of delivering conditions of a liquid delivering head and fixing conditions of a fixing means of a specified first printing unit in accordance with a plurality of the detecting areas, a printing result detecting means 13 for detecting the printing results of a plurality of the detecting areas, and a second delivering and fixing condition setting means which sets delivering conditions of the liquid delivering heads and fixing conditions of the fixing means of the printing units arranged on the downstream side in the conveying direction of the recording medium more than the first printing unit based on the detecting results by the printing result detecting means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and an image forming method, and more particularly to a technique for controlling fixing conditions and ejection conditions in a system for forming an image using radiation curable ink.

  2. Description of the Related Art Conventionally, an image forming apparatus has an inkjet head in which a large number of nozzles are arranged, and ink is ejected as droplets from the nozzle toward the recording medium while relatively moving the inkjet head and the recording medium. Thus, an ink jet printer (ink jet recording apparatus) that forms an image on a recording medium is known.

  In particular, in such an inkjet image forming apparatus, a technique using a radiation curable ink such as an ultraviolet curable ink (so-called UV ink) is known.

  This is because radiation curable ink that has been ejected onto a recording medium is irradiated with radiation and cured at an early stage, thereby preventing bleeding on the recording medium and overlapping of ink droplets to prevent image quality. In addition, the recording speed can be increased.

  As such a UV curable ink, for example, a test print is printed using the UV curable ink, and the UV curable ink of the test print is worn by being scratched with a stylus or the like. By automatically changing printing parameters such as curing conditions (irradiation time (conveying speed)), temperature, and heat source intensity, the time and effort required to optimize printing parameters manually can be eliminated. Further, there has been known one that attempts to solve the problem that the final image has a difference depending on the subjectivity of the worker (for example, see Patent Document 1).

  Further, for example, it is determined whether the dot diameter of the test pattern image is a predetermined size, and the image recording conditions such as ejection conditions (ink droplet amount, number of droplets), curing conditions (time until ultraviolet irradiation) or surface treatment conditions are changed. Thus, there is a known one that attempts to record a high-quality image with a predetermined dot diameter regardless of the type of media, the aging of the irradiation device, and the ink curability variation due to temperature and humidity changes ( For example, see Patent Document 2).

Also, if the lighting time of the ultraviolet lamp exceeds 1000 hours, the output becomes 70 to 80%. Therefore, the UV ink cannot be completely cured, and some inks are difficult to cure. There is a problem that the image quality deteriorates.To cope with this, for example, a print test pattern configured so as to satisfy conditions that make it difficult to cure ink is printed, and light quality is determined based on the result of judging the quality. It is known that the speed (irradiation time) at which the irradiation means moves is changed, and the timing (ejection frequency) at which the ink is ejected from the nozzle is changed according to the changed speed (for example, (See Patent Document 3 etc.).
Special table 2004-516959 gazette JP 2004-291418 A JP 2005-199630 A

  However, any of the above-described patent documents 1 to 3 outputs a test pattern first, measures the output test pattern, and records an image such as an ejection condition and a fixing condition based on the determination result. Since the condition is changed, there is a problem that the image recording condition cannot be changed in real time according to a change in the situation during printing.

  In addition, since a test pattern is required, preparation is necessary before the actual printing, productivity is poor, and the printing of the test pattern causes waste of media, ink, power, etc., and the run cost is high. There's a problem.

  The present invention has been made in view of such circumstances, and can detect fluctuating print quality, optimize image recording conditions in real time, reduce run costs, and improve productivity. An object is to provide an image forming apparatus and an image forming method.

  In order to achieve the above object, the invention according to claim 1 is an image forming apparatus for printing an image on a recording medium while conveying the recording medium to a liquid discharge head, wherein the conveying path of the recording medium A plurality of printing units having a liquid discharge head and fixing means, a detection area setting means for setting a plurality of detection areas in an image printed on the recording medium, and the plurality of printing units. Among these, a first discharge / fixing condition setting means capable of setting a plurality of discharge conditions of the liquid discharge head and fixing conditions of the fixing means of a predetermined first printing unit in correspondence with the plurality of detection areas. A print result detecting means for detecting a print result printed in each of the plurality of detection areas, and a print unit disposed downstream of the first print unit in the transport direction of the recording medium. And a second discharge / fixing condition setting unit for setting the discharge condition of the liquid discharge head and the fixing condition of the fixing unit based on the detection result of the print result detection unit. A forming apparatus is provided.

  As a result, the print quality that fluctuates due to various factors can be detected in real time and the optimum image forming conditions can be determined, so that a high-quality image can be obtained.

  According to a second aspect of the present invention, the liquid discharge head is a line type head. Thus, high-speed printing is possible particularly when the liquid discharge head is a line head.

  According to a third aspect of the present invention, the printing unit includes a liquid discharge head that discharges a processing liquid and a liquid discharge head that discharges ink. Thus, by discharging the processing liquid and ink, it is possible to improve the quality of the image and improve the productivity.

  According to a fourth aspect of the present invention, the liquid ejection head of the first printing unit ejects ink having the lowest visibility among the plurality of inks ejected by the plurality of printing units. And As described above, since the condition is set using the detection result of the ink with the lowest visibility among the plurality of inks ejected by the print head, the detection and real-time detection can be performed while ensuring the print quality. Condition setting is possible.

  According to a fifth aspect of the present invention, the fixing unit of the first printing unit can set a plurality of different fixing conditions in the width direction of the recording medium conveyance path.

  According to a sixth aspect of the present invention, a plurality of the print result detecting means are provided corresponding to the plurality of fixing conditions.

  Thereby, it becomes possible to determine about several conditions simultaneously.

  According to a seventh aspect of the present invention, there is provided a table for correcting the discharge conditions and the fixing conditions set for the second printing unit and the following in accordance with the detection result in consideration of a change with time and an environmental change. It is provided with.

  This makes it possible to set more optimal conditions.

  In addition, according to an eighth aspect of the present invention, the treatment liquid includes a curing initiator, and the ink includes a coloring material and a curing main agent.

  Thereby, productivity can be improved.

  Similarly, in order to achieve the above object, according to a ninth aspect of the present invention, a plurality of print units each having a liquid discharge head and a fixing unit are arranged along a recording medium conveyance path, and the plurality of print units are An image is formed by ejecting the liquid ejection head of a predetermined first printing unit of the first printing unit under at least one ejection condition and then fixing the image by at least one fixing condition by the fixing unit of the first printing unit. Then, a printing result in a detection area designated in advance in the formed image is detected by a detecting means installed immediately after a fixing means of the first printing unit, and the recording is performed more than the first printing unit. The discharge condition of the liquid discharge head and the fixing condition of the fixing unit of the printing unit arranged on the downstream side in the medium conveying direction are set according to the detection result. To provide an image forming method, comprising and.

  As a result, the run cost is reduced, the productivity is improved, the discharge conditions and the fixing conditions are optimized, and high-quality image formation is possible.

  As described above, according to the present invention, it is possible to detect the print quality that fluctuates due to various factors in real time and determine the optimum image forming conditions, so that a high-quality image can be obtained. In addition, when the condition is set using the detection result of the color ink having low visibility, the detection and the condition setting in real time can be performed while ensuring the print quality.

  Hereinafter, an image forming apparatus and an image forming method according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is an overall configuration diagram showing an outline of a first embodiment of an ink jet recording apparatus as an image forming apparatus according to the present invention.

  As shown in FIG. 1, the inkjet recording apparatus 10 includes a printing unit 12 having a plurality of printing units 12-1, 12-2, 12-3, and 12-4 provided for each ink color, and a printing unit. An ink storage / loading unit 14 for storing a liquid to be supplied to each of the 12 printing units 12-1, 12-2, 12-3, and 12-4, a paper feeding unit 18 for supplying a recording paper 16, and a recording The decurling unit 20 for removing the curl of the paper 16 and the nozzle surfaces of the print units 12-1, 12-2, 12-3, 12-4 of the print unit 12 (not shown, details will be described later) A transport unit 22 that is disposed opposite to (a discharge surface that discharges a liquid such as ink) and transports the recording paper 16 while maintaining the flatness of the recording paper 16, and a print detection unit that reads a printing result by the printing unit 12 24 and printed recording paper (print And a discharge unit 26 for discharging the objects) to the outside.

  In FIG. 1, a magazine for rolled paper (continuous paper) is shown as an example of the paper supply unit 18, but a plurality of magazines having different paper widths, paper quality, and the like may be provided side by side. Further, instead of the roll paper magazine or in combination therewith, the paper may be supplied by a cassette in which cut papers are stacked and loaded.

  In the case of an apparatus configuration using roll paper, a cutter 28 is provided as shown in FIG. 1, and the roll paper is cut into a desired size by the cutter 28. The cutter 28 includes a fixed blade 28A having a length equal to or greater than the conveyance path width of the recording paper 16, and a round blade 28B that moves along the fixed blade 28A. The fixed blade 28A is provided on the back side of the print. The round blade 28B is arranged on the print surface side with the conveyance path interposed therebetween. Note that the cutter 28 is not necessary when cut paper is used.

  When multiple types of recording paper are used, an information recording body such as a barcode or wireless tag that records paper type information is attached to the magazine, and the information on the information recording body is read by a predetermined reader. Therefore, it is preferable to automatically determine the type of paper to be used and perform ink ejection control so as to realize appropriate ink ejection according to the type of paper.

  The recording paper 16 delivered from the paper supply unit 18 retains curl due to having been loaded in the magazine. In order to remove this curl, heat is applied to the recording paper 16 by the heating drum 30 in the direction opposite to the curl direction of the magazine in the decurling unit 20. At this time, it is more preferable to control the heating temperature so that the printed surface is slightly curled outward.

  After the decurling process, the cut recording paper 16 is sent to the transport unit 22. The conveyance unit 22 has a structure in which an endless belt 33 is wound between rollers 31 and 32, and at least a portion facing the nozzle surface of the printing unit 12 and the sensor surface of the printing detection unit 24 is a flat surface (flat surface). ).

  The belt 33 has a width that is wider than the width of the recording paper 16. The conveyance unit 22 shown in FIG. 1 shows an example of an adsorption belt conveyance unit that adsorbs and conveys the recording paper 16 to the belt 33 using negative pressure, but the conveyance unit 22 is limited to this. is not. The recording paper 16 may be attracted to the belt 33 and conveyed by using static electricity.

  In the case of the suction belt conveyance unit using negative pressure, a number of suction holes (not shown) are formed on the belt surface of the belt 33. As shown in FIG. 1, an adsorption chamber 34 is provided at a position facing the nozzle surface of the printing unit 12 and the sensor surface of the printing detection unit 24 inside the belt 33 spanned between the rollers 31 and 32. By sucking the suction chamber 34 with a fan 35 to make it a negative pressure, the recording paper 16 on the belt 33 is sucked and held.

  The power of a motor (not shown) is transmitted to at least one of the rollers 31 and 32 around which the belt 33 is wound, so that the belt 33 is driven in the clockwise direction in FIG. The recording paper 16 is conveyed from left to right in FIG.

  Since ink adheres to the belt 33 when a borderless print or the like is printed, the belt cleaning unit 36 is provided at a predetermined position outside the belt 33 (an appropriate position other than the print area). Although details of the configuration of the belt cleaning unit 36 are not shown, for example, there are a method of niping a brush roll, a water absorbing roll, etc., an air blowing method of spraying clean air, or a combination thereof. In the case where the cleaning roll is nipped, the cleaning effect is great if the belt linear velocity and the roller linear velocity are changed.

  In addition, although the aspect using a roller nip conveyance mechanism as the conveyance part 22 is also considered, since a roller will contact the printing surface of a sheet | seat immediately after printing if a roller nip conveyance is carried out in a printing area, there exists a problem that an image is easy to spread. is there. Therefore, as in this example, suction belt conveyance that does not contact the image surface in the printing region is preferable.

  The printing unit 12 is a so-called full-line type head in which line-type heads having a length corresponding to the maximum paper width are arranged in a direction (main scanning direction) orthogonal to the paper transport direction (sub-scanning direction) ( (See FIG. 3).

  From the upstream side (left side in FIG. 1) along the conveyance direction (paper conveyance direction) of the recording paper 16, yellow (Y), magenta (M), cyan (C), and black (K) correspond to each color ink in this order. Printing units 12-1, 12-2, 12-3, and 12-4 having printing heads are arranged. That is, the inkjet recording apparatus 10 of the present embodiment has the same number of printing units 12-1, 12-2, 12-3, and 12-4 as the number of colors. A color image can be formed on the recording paper 16 by discharging the color ink from the print heads of the printing units 12-1, 12-2, 12-3, and 12-4 while conveying the recording paper 16.

  Thus, according to the printing unit 12 in which the full line head that covers the entire width of the paper is provided for each ink color, the recording paper 16 and the printing unit 12 are relatively moved in the paper transport direction (sub-scanning direction). It is possible to record an image on the entire surface of the recording paper 16 by performing this operation only once (that is, by one sub-scan). Accordingly, high-speed printing is possible as compared with a shuttle type head in which the print head reciprocates in a direction (main scanning direction) orthogonal to the paper transport direction, and productivity can be improved.

  Here, the main scanning direction and the sub-scanning direction are used in the following meaning. That is, when driving the nozzles with a full line head having a nozzle row corresponding to the full width of the recording paper, (1) whether all the nozzles are driven simultaneously or (2) whether the nozzles are driven sequentially from one side to the other (3) The nozzles are divided into blocks, and each nozzle is driven sequentially from one side to the other for each block, and the width direction of the paper (perpendicular to the conveyance direction of the recording paper) Nozzle driving that prints one line (a line made up of a single row of dots or a line made up of a plurality of rows of dots) in the direction of scanning is defined as main scanning. A direction indicated by one line (longitudinal direction of the belt-like region) recorded by the main scanning is called a main scanning direction.

  On the other hand, by relatively moving the above-described full line head and the recording paper, printing of one line (a line formed by one line of dots or a line composed of a plurality of lines) formed by the above-described main scanning is repeatedly performed. Is defined as sub-scanning. A direction in which sub-scanning is performed is referred to as a sub-scanning direction. After all, the conveyance direction of the recording paper is the sub-scanning direction, and the direction orthogonal to it is the main scanning direction.

  In this example, the configuration of the standard colors (4 colors) of YMCK is exemplified. However, the combination of ink colors and the number of colors is not limited to this embodiment, and light ink and dark ink are added as necessary. May be. For example, it is possible to add a print head that discharges light ink such as light cyan and light magenta.

  As described above, the first color printing unit 12-1 is assumed to correspond to yellow (Y), and the second color printing unit 12-2 is magenta (M) and the third color printing unit 12-3. The reason why C is cyan (C) and the fourth color printing unit 12-4 is black (K) is to perform printing in the order of poor visibility.

  If light ink is present, the ink is ejected from the first color printing unit 12-1.

  As shown in FIG. 1, the ink storage / loading unit 14 stores tanks 14Y and 14M that store inks of colors corresponding to the print heads of the print units 12-1, 12-2, 12-3, and 12-4. , 14C, 14K and a tank 14S for storing the processing liquid, and each tank communicates with each print head and the processing liquid head via a pipe line (not shown). Further, the ink storage / loading unit 14 includes notifying means (display means, warning sound generating means, etc.) for notifying when the ink remaining amount is low, and has a mechanism for preventing erroneous loading between colors. is doing.

  The print detection unit 24 includes an image sensor (line sensor or the like) for imaging the droplet ejection result of the print unit 12, and means for checking nozzle clogging and other ejection defects from the droplet ejection image read by the image sensor. Function as.

  The print detection unit 24 of this example has a light receiving element array that is wider than at least the ink ejection width (image recording width) by the print heads of the print units 12-1, 12-2, 12-3, and 12-4. Consists of line sensors. The line sensor includes an R sensor row in which photoelectric conversion elements (pixels) provided with red (R) color filters are arranged in a line, a G sensor row provided with green (G) color filters, The color separation line CCD sensor includes a B sensor array provided with a blue (B) color filter. Instead of the line sensor, an area sensor in which the light receiving elements are two-dimensionally arranged can be used.

  The print detection unit 24 reads the test patterns printed by the print heads of the print units 12-1, 12-2, 12-3, and 12-4 corresponding to the respective colors, and detects the ejection of each head. The ejection determination includes the presence / absence of ejection, measurement of dot size, measurement of dot landing position, and the like.

  A post-drying unit 42 is provided following the print detection unit 24. The post-drying unit 42 is means for drying the printed image surface, and for example, a heating fan is used. Since it is preferable to avoid contact with the printing surface until the ink after printing is dried, a method of blowing hot air is preferred.

  When printing on porous paper with dye-based ink, the weather resistance of the image is improved by preventing contact with ozone or other things that cause dye molecules to break by blocking the paper holes by pressurization. There is an effect to.

  A heating / pressurizing unit 44 is provided following the post-drying unit 42. The heating / pressurizing unit 44 is a means for controlling the glossiness of the image surface, and pressurizes with a pressure roller 45 having a predetermined uneven surface shape while heating the image surface to transfer the uneven shape to the image surface. To do.

  The printed matter generated in this manner is outputted from the paper output unit 26. It is preferable that the original image to be printed (printed target image) and the test print are discharged separately. The ink jet recording apparatus 10 is provided with a selecting means (not shown) for switching the paper discharge path in order to select the printed matter of the main image and the printed matter of the test print and send them to the respective discharge portions 26A and 26B. ing. Note that when the main image and the test print are simultaneously formed in parallel on a large sheet, the test print portion is separated by a cutter (second cutter) 48. The cutter 48 is provided immediately before the paper discharge unit 26, and cuts the main image and the test print unit when the test print is performed on the image margin. The structure of the cutter 48 is the same as that of the first cutter 28 described above, and includes a fixed blade 48A and a round blade 48B.

  Although not shown, the paper output unit 26A for the target prints is provided with a sorter for collecting prints according to print orders.

  FIG. 2 shows an enlarged part of the printing unit 12. That is, in FIG. 2, three printing units 12-1, 12-2, and 12-3 are displayed. The other printing unit 12-4 is the same as the printing unit 12-2 or 12-3.

  Each printing unit 12-1, 12-2, 12-3 has a headset 12-1HS, 12-2HS, 12-3HS and a fixing unit 12-1TC, 12-2TC, 12-3TC, respectively. . Each of the headsets 12-1HS, 12-2HS, and 12-3HS includes a processing liquid head 12S that discharges a processing liquid and print heads 12Y, 12M, and 12C that discharge ink of each color. Further, the fixing units 12-1TC, 12-2TC, and 12-3TC are respectively provided from a fixing lamp 12L that is installed so as to be movable in the conveyance direction of the recording paper 16 indicated by an arrow A in the drawing along the guide rail 12G. It is configured.

  In particular, immediately after the fixing unit 12-1TC of the printing unit 12-1 for the first color (the most upstream side), a print result detection for optically detecting the density and shape of the detection area in the printed image. Means 13 are arranged. The print result detection unit 13 is configured by a line sensor similar to the print detection unit 24 described above, for example. As will be described in detail later, according to the discharge result of the first color ink, the image recording conditions such as fixing conditions and discharge conditions are changed in real time, and the second and subsequent colors are printed under the changed conditions. Because.

  The processing liquid used in the image forming apparatus 10 of this embodiment contains a curing (polymerization) initiator. Each color ink (UV curable ink) is composed of a main curing agent (UV curable component such as a monomer, oligomer, low molecular weight homopolymer, copolymer or the like) that is cured (polymerized) by applying UV (ultraviolet) energy, and a coloring material. (Colorant). Note that the treatment liquid may contain a diffusion inhibitor and a high-boiling organic solvent.

  The processing liquid and ink will be described in detail later.

  As described above, the combination of the processing liquid and each color ink avoids image deterioration due to landing interference mainly by the function of the diffusion preventing agent contained in the processing liquid, and leaks light from the fixing lamp 12L and reflection by the recording paper 16. Even when light hits the nozzles of the print heads 12Y, 12M, 12C, and 12K and the treatment liquid head 12S, each liquid does not contain a curing initiator and a curing main agent, and therefore a curing reaction (polymerization reaction). Does not occur, and solidification of the processing liquid and ink in the nozzles of each head is prevented.

  Further, the fixing lamp 12L is movable in the conveying direction of the recording paper 16 along the guide rail 12G, thereby changing the time until the fixing is started after the processing liquid and ink land on the recording paper 16. It becomes possible to do. As a result, an effect equivalent to changing the linear velocity for conveying the recording paper 16 can be obtained.

  The recording paper 16 is adsorbed and conveyed on the belt 33 guided by the roller 31. When the fixing lamp 12L is irradiated with UV light, the recording paper 16 is heated to accelerate fixing. 37 is disposed on the back side of the belt 33 corresponding to the position of the fixing lamp 12L.

  Contrary to the configuration of each of the above liquids, the same effects as described above can be obtained when each color ink contains a curing initiator and the treatment liquid contains a curing main agent (UV monomer). .

  FIG. 3 shows a plan perspective view of the vicinity of the printing unit 12 corresponding to FIG.

  As shown in FIG. 3, the recording paper 16 is conveyed along the conveyance path 38 on the belt 33 guided by the roller 31 (upward in the drawing). On the upper side of the belt 33, a first color printing unit 12-1, a second color printing unit 12-2, a third color printing unit 12-3, and a fourth color printing unit 12-4 are arranged in this order. Has been.

  The first color printing unit 12-1 includes a fixing unit 12 including a processing liquid head 12S, a headset 12-1HS including a printing head 12Y that discharges yellow ink, and a fixing lamp 12L movable along a guide rail 12G. -1TC and printing result detection means 13.

  In particular, in the fixing unit 12-1TC of the first color printing unit 12-1, three guide rails 12G are arranged in the width direction along the transport direction, and the recording paper 16 is provided for each guide rail 12G. The fixing lamp 12L is installed so as to be movable in the transport direction. Also, three heaters 37 are provided in the width direction so that the respective portions can be separately heated below the three guide rails 12G. As a result, three levels of fixing conditions can be set in the width direction of the recording paper 16, with the temperature of the conveyance path and the time from landing to the start of fixing differing from each other.

  The print result detecting means 13 includes three detection sensors 13a, 13b, and 13c in the width direction so that the print results for the three fixing conditions in the width direction can be detected separately. As described above, the print result detecting means 13 has a number of detection sensors (13a,...) Corresponding to different fixing conditions.

  At this time, as shown in FIG. 3, when the discharge image 17 is printed on the recording paper 16 as indicated by a broken line, the detection sensors are arranged in the width direction of the recording paper 16 from the discharge images 17. Three detection areas 19 corresponding to 13a, 13b, and 13c are set, and image recording is performed by changing the image recording conditions (ejection conditions and fixing conditions) of each ejection image 17, and the printing result for each detection area 19 is printed. Can be detected.

  The second color printing unit 12-2 includes a processing liquid head 12S and a headset 12-2HS including a printing head 12M that discharges magenta ink, a fixing unit 12-2TC including a guide rail 12G and a fixing lamp 12L, and a recording. The heater 16 is arranged below the fixing unit 12-2TC over the entire width direction of the paper 16.

  The configuration of the printing unit 12-3 for the third color is the same as the configuration of the printing unit 12-2 for the second color except that the headset 12-3HS has a printing head 12C that discharges cyan ink. . The configuration of the printing unit 12-4 for the fourth color also includes the printing unit 12-2 for the second color and the printing unit 12 for the third color except that the headset 12-4HS has a printing head 12K that discharges black ink. The configuration is the same as that of -3.

  Thereby, in the printing units 12-2, 12-3, and 12-4 for the second and subsequent colors, the temperature of the conveyance path and the time from landing to the start of fixing can be changed.

  In this embodiment, in this way, in the first color printing unit 12-1, the printing result detection unit 13 detects the result of printing by changing the image recording conditions (fixing conditions, printing conditions) to a plurality of levels. Each level detection result is compared with the target value, and the conditions for obtaining the result closest to the target value are determined as the image recording conditions (fixing conditions, downstream) of the second to fourth printing units 12-2 to 12-4. By setting the discharge condition as a discharge condition, it is possible to record an image with high image quality by changing the image recording condition to an optimum one in real time during the formation of one image.

  Next, the structure of the head will be described. Since the structure of the treatment liquid head 12S and the print heads 12Y, 12M, 12C, and 12K of the respective colors are common, the head 50 is simply represented by the reference numeral 50 below.

  FIG. 4A is a plan perspective view showing a structural example of the head 50.

  In order to increase the dot pitch printed on the recording paper 16, it is necessary to increase the nozzle pitch in the head 50. As shown in FIG. 4A, the head 50 of this example includes a nozzle 51 that is an ink droplet ejection port, a pressure chamber 52 corresponding to each nozzle 51, and an ink supply port 53 that supplies ink to the pressure chamber 52. The pressure chamber units 54 composed of, etc. are arranged in a staggered matrix (two-dimensionally), and are projected so as to be arranged along the longitudinal direction of the head (direction perpendicular to the recording paper conveyance direction). High density of substantial nozzle interval (projection nozzle pitch) is achieved.

  The form in which the nozzle row having a length corresponding to the entire width of the recording paper 16 is configured in a direction substantially orthogonal to the feeding direction of the recording paper 16 is not limited to that shown here. For example, instead of the configuration shown in FIG. 4A, although not shown in the drawing, the entire width of the recording paper 16 is obtained by arranging short head units in which a plurality of nozzles 51 are arranged two-dimensionally and connecting them in a staggered manner. You may comprise the line head which has a nozzle row of the length corresponding to.

  As shown in FIG. 4A, the pressure chamber 52 provided corresponding to each nozzle 51 of the head 50 has a substantially square planar shape, and the nozzle 51 and the ink are formed at both corners of the diagonal line. A supply port 53 is provided. In addition, the shape of the pressure chamber 52 is not limited to a square as described above, and the planar shape thereof may be various such as a quadrangle (diamond, rectangle, etc.), a pentagon, a hexagon, other polygons, a circle, an ellipse, and the like. It can be a shape.

  FIG. 4B shows a cross-sectional view of the pressure chamber unit 54 taken along the line 4B-4B in FIG.

  As shown in FIG. 4B, each pressure chamber 52 communicates with a common liquid chamber 55 via an ink supply port 53. The common liquid chamber 55 communicates with an ink tank, which is an ink supply source (not shown), and ink supplied from the ink tank is distributed and supplied to each pressure chamber 52 via the common liquid chamber 55.

  A piezoelectric element (actuator) 58 having individual electrodes 57 is joined to the upper side of the diaphragm 56 that constitutes the top surface of the pressure chamber 52 and also serves as a common electrode. By applying a driving voltage to the individual electrode 57, the piezoelectric element 58 is deformed and the volume of the pressure chamber 52 is reduced, and the ink in the pressure chamber 52 is ejected from the nozzle 51 by the pressure change accompanying this. After ink ejection, when the volume of the pressure chamber 52 is restored, new ink is supplied from the common liquid chamber 55 through the ink supply port 53 to the pressure chamber 52.

  FIG. 5 is a principal block diagram showing the system configuration of the inkjet recording apparatus 10.

  As shown in FIG. 5, the inkjet recording apparatus 10 of the present embodiment includes a communication interface 70, a system controller 72, an image memory 74, a motor driver 76, a heater driver 78, a print control unit 80, an image buffer memory 82, and a print head driver. 84, a processing liquid head driver 86, a fixing means driver 90, and the like.

  The communication interface 70 is an interface unit that receives image data sent from the host computer 92. As the communication interface 70, a serial interface such as USB, IEEE 1394, Ethernet, or wireless network, or a parallel interface such as Centronics can be applied. In this part, a buffer memory for speeding up communication may be mounted.

  Image data sent from the host computer 92 is taken into the inkjet recording apparatus 10 via the communication interface 70 and temporarily stored in the image memory 74. The image memory 74 is a storage unit that temporarily stores an image input via the communication interface 70, and data is read and written through the system controller 72. The image memory 74 is not limited to a memory made of a semiconductor element, and a magnetic medium such as a hard disk may be used.

  The system controller 72 includes a central processing unit (CPU) and its peripheral circuits, and functions as a control device that controls the entire inkjet recording apparatus 10 according to a predetermined program, and also functions as an arithmetic device that performs various calculations. . That is, the system controller 72 controls each part of the communication interface 70, the image memory 74, the motor driver 76, the heater driver 78, etc., performs communication control with the host computer 92, read / write control of the image memory 74, etc. A control signal for controlling the motor 94 and the heater 89 of the transport system is generated.

  Note that programs executed by the CPU of the system controller 72 and various data necessary for control are stored in a ROM (not shown) or the like. The image memory 74 is used as a temporary storage area for image data, and is also used as a program development area and a calculation work area for the CPU.

  The motor driver 76 is a driver (driving circuit) that drives the conveyance motor 94 in accordance with an instruction from the system controller 72. The heater driver 78 is a driver that drives the heater 89 such as the post-drying unit 42 in accordance with an instruction from the system controller 72.

  The print control unit 80 has a signal processing function for performing various processing and correction processing for generating a print control signal from the image data in the image memory 74 according to the control of the system controller 72, and the generated print It is a control unit that supplies data (dot data) to the head driver 84.

  The print control unit 80 includes an image buffer memory 82, and image data, parameters, and other data are temporarily stored in the image buffer memory 82 when image data is processed in the print control unit 80. In FIG. 5, the image buffer memory 82 is shown in a form associated with the print control unit 80, but it can also be used as the image memory 74. Also possible is an aspect in which the print controller 80 and the system controller 72 are integrated and configured with one processor.

  Image data to be printed is input from the outside via the communication interface 70 and stored in the image memory 74. At this stage, for example, RGB image data is stored in the image memory 74.

  The image data stored in the image memory 74 is sent to the print control unit 80 via the system controller 72, and the print control unit 80 is supplied to the print control unit 80 for each ink color by a halftoning technique such as a dither method or an error diffusion method. Converted to dot data. In the ink jet recording apparatus 10, a pseudo continuous tone image is formed by changing the droplet ejection density and dot size of fine dots with ink (coloring material) to the human eye. It is necessary to convert to a dot pattern that reproduces the gradation (shading of the image) as faithfully as possible.

  That is, the print control unit 80 performs processing for converting the input RGB image data into dot data of four colors Y, M, C, and K. Further, the print controller 80 discriminates the treatment liquid droplet ejection area (the area on the recording surface where the treatment liquid droplet ejection is necessary) based on the dot data of each color, and generates the treatment liquid droplet ejection dot data. . In this way, the dot data (for the treatment liquid and for each color) generated by the print control unit 80 is stored in the image buffer memory 82.

  The print head driver 84 generates drive control signals for the print heads 12Y, 12M, 12C, and 12K for the respective color inks based on the print data (that is, dot data stored in the image buffer memory 82) given from the print control unit 80. Generate. Further, the processing liquid head driver 86 generates a drive control signal for the processing liquid head 12S.

  When the drive control signal generated by the processing liquid head driver 86 is applied to the piezoelectric element 58 of the processing liquid head 12S, the processing liquid is discharged from the corresponding nozzle 51 of the processing liquid head 12S and generated by the print head driver 84. By applying the drive control signal to the piezoelectric elements 58 of the print heads 12Y, 12M, 12C, and 12K, ink is ejected from the corresponding nozzles 51 of the print heads 12Y, 12M, 12C, and 12K.

  An image is formed on the recording paper 16 by controlling the ejection of the processing liquid from the processing liquid head 12S and the ejection of ink from the print heads 12Y, 12M, 12C, and 12K in synchronization with the conveyance speed of the recording paper 16. . As described above, required signal processing is performed in the print control unit 80, and droplets of the processing liquid are ejected via the processing liquid head driver 86 and the print head driver 84 based on the print data. The discharge timing is controlled. Thereby, a desired dot size and dot arrangement are realized.

  The printing result detecting means 13 is provided in the printing unit 12-1 for the first color, detects the printing result with yellow ink by the headset 12-1HS of the printing unit 12-1 for the first color, and the detection result is displayed. Provided to the print controller 80.

  The print control unit 80 according to the present embodiment includes a first discharge / fixing condition setting unit 95 that sets a plurality of fixing conditions and discharge conditions for the first printing unit 12-1 from a preset table set in advance, and a print result. A dot diameter calculation unit 96 that calculates a dot diameter (line diameter) based on the result detected by the detection means 13, and has a target value for the dot diameter (line diameter) and calculates the dot diameter (line diameter) calculated above. A dot diameter comparison unit 98 that compares with a target value of the diameter (line diameter), a second discharge / fixing condition unit 100 that sets an optimum condition based on the comparison result, a time and environment of the fixing unit with respect to the set condition A correction coefficient calculation unit 102 that calculates a correction coefficient for performing correction in consideration of data such as ink characteristics, and a detection area setting unit 1 that sets a detection area that is a print result detection target from the print data It has four. In addition, the print control unit 80 fixes the correction based on the correction condition 106 in addition to the selected conditions in consideration of data such as time, environment, and ink characteristics of the fixing unit, and the correction coefficient. A memory 110 is provided for storing a modified set value derivation table 108 for calculating conditions and discharge conditions. Of course, the correction table 106 and the correction setting value derivation table 108 may be held in the print control unit 80.

  Hereinafter, control of image recording conditions (fixing conditions, ejection conditions) in the image forming method of the present embodiment will be described.

  FIG. 6 is a flowchart schematically showing the image forming method of the present embodiment.

  First, as shown in step S100 of FIG. 6, when a print instruction is issued, in step S102, the print controller 80 reads image data from the image memory 74, expands the data, and stores it in the image buffer memory 82.

  Next, in step S104, the detection area setting unit 104 of the print control unit 80 sets a detection area in an image to be printed as indicated by reference numeral 19 in FIG. This is set from the portion where the color of the first color printing unit 12-1 (yellow in this example) is present. At this time, if the first color ink is not ejected, for example, a line is dummy ejected with the first color ink (yellow in this example) to a location where another color ink is ejected later, and this is detected. To do. Since the first color ink is an ink with low visibility, other color inks are ejected later on this, so there is no particular problem with the image quality of the recorded image. Alternatively, this may be detected by dummy discharging a line outside the area where the image is recorded.

  Next, in step S106, the first discharge / fixing condition setting unit 95 sets N fixing conditions and discharge conditions from a preset table. For example, based on the preset table based on the media type, ink type, print mode, etc., a plurality of levels are set in the width direction of the recording paper (medium) 16 for the fixing conditions and ejection conditions of the first color printing unit 12-1. Like that.

  Specifically, the conveyance guide temperature of the fixing unit 12-1TC is set in three stages: high, medium, and low. Further, the time from when the liquid has landed on the recording paper 16 until the fixing is started by the fixing unit 12-1TC is set in three stages: short, standard, and long. In addition, the intensity of the fixing light source (fixing lamp 12L) is set in three levels: large, medium and small. Furthermore, the level of the mixing ratio of the first liquid (treatment liquid) and the second liquid (ink) is shaken in a plurality of stages. In this way, by setting a plurality of levels for each condition, a plurality of fixing conditions and ejection conditions are set.

  In the example shown in FIG. 3, the position of the fixing lamp 12L is shifted to three different positions, and the time from the discharge of the processing liquid from the processing liquid head 12S and the discharge of the ink from the print head 12Y to the start of fixing. By setting three types, three types of fixing conditions are set.

  At this time, information such as the type of recording paper 16, the type of ink, and the state of the fixing lamp 12L is acquired in advance, and based on these, fixing conditions and ejection conditions are set from a preset table.

  Next, in step S <b> 108, the correction coefficient calculation unit 102 calculates a correction coefficient for each of the printing units 12-2, 12-3, and 12-4 for the second and subsequent colors from the correction table 106. At this time, the ink used in each of the printing units 12-2, 12-3, and 12-4, the usage time of the fixing lamp 12L, and the like are known, and the correction coefficient is calculated based on this.

  FIG. 7 shows an example of the correction table 106.

  In the correction table 106 exemplified here, items to be corrected include, for example, the ink type, the time from ink replacement, the usage time of the fixing lamp, the temperature of the fixing unit, and the ink amount. As the type of ink, for example, black ink generally has a high density, so that the correction coefficient is 0.9 for normal ink. On the contrary, since the light ink has a low density of the color material, the light ink is easily solidified.

  When the time since ink replacement is long, for example, in this example, when it is longer than one month, the performance of the curing initiator deteriorates over time, so that it is difficult to solidify, so the correction coefficient is set to 0.9. If the usage time of the fixing lamp is long, and 1000 hours or more have elapsed in this example, the illuminance decreases and it becomes difficult to solidify, so the correction coefficient is set to 0.7.

  Further, when the temperature difference between the fixing portions is different by 10 degrees or more, there is a difference in the manner of solidification, so that the temperature difference of the fixing lamp is compensated. Further, since it is difficult to cure when the amount of ink is large, the correction coefficient is set to 0.9. Conversely, when the amount of ink is small, it is easy to cure, and the correction coefficient is set to 1.1.

  When a plurality of conditions overlap, the product of the correction coefficients is taken. For example, when the usage time of the fixing lamp in the light ink system exceeds 1000 hours, 1.1 × 0.7 = 0.77 is set to about 0.8.

  Next, in step S110, printing is started. That is, the recording paper 16 is fed from the paper feeding unit 18 and conveyed toward the printing unit 12.

  First, in step S112, based on a control signal from the processing liquid head driver 86, a curing initiator and a diffusion inhibitor are used as the first liquid from the processing liquid head 12S of the headset 12-1HS of the first printing unit 12-1. The processing liquid containing is discharged.

  Next, in step S114, based on the control signal from the print head driver 84, the first color material and the curing main agent are contained as the second liquid from the print head 12Y of the first color ejection unit 12-1 (yellow). ) Ink is ejected.

  Next, in step S116, when the recording paper 16 on which the processing liquid and the first color ink are ejected is conveyed to the fixing unit 12-1TC (see FIG. 3), according to the N fixing conditions set above. Fixing is started. At this time, in the example shown in FIG. 3, three types of fixing conditions are set in the width direction.

  After the recording paper 16 is fixed by the fixing unit 12-1TC, the recording paper 16 is conveyed under the print result detecting means 13. In step S118, the print result detection unit 13 detects the print result corresponding to each of the N fixing conditions. In the example shown in FIG. 3, three fixing conditions are set, and three types of detection results are obtained by the three detection sensors 13a, 13b, and 13c.

  In this way, the print result detection unit 13 reads the printed line of the detection target portion, and the detected data is sent to the print control unit 80. In step S120, the dot diameter calculation unit 96 sets the line diameter (for each fixing condition). Dot diameter) is calculated.

  The method for calculating the line diameter is not particularly limited. For example, the line diameter is calculated by converting the image signal acquired through the CCD image sensor of the print result detecting unit 13 into a digital signal and performing image processing. The line diameter can be calculated by quantifying the quality of the line.

  The line diameter calculation method is disclosed in, for example, Japanese Patent Application No. 2004-282648 filed by the present applicant. According to this method, the line width A, blur B, distortion C, contrast D, density E, and density uniform difference F are first detected from the data of the detected image obtained by photographing the line of the target image by the print result detecting means 13. And the like, and each of these items is quantified in accordance with, for example, ISO 13660.

  Then, the sum of the respective measured values, line width A, blur B, distortion C, contrast D, density E and density uniform difference F multiplied by weighting factors a to f is set as a judgment value Q, The maximum value is taken as the line diameter. In this way, the line diameter is calculated for each of a plurality of fixing conditions.

  Next, in step S122, the dot diameter comparison unit 98 compares the line diameter calculated for each of the plurality of fixing conditions with a target value of a preset line diameter. Next, in step S124, as a result of the comparison, the fixing conditions for the line closest to the target value are set in the second ejection / fixing condition setting unit 100 for the second and subsequent printing units 12-2, 12-3, 12-. 4 is set as the fixing condition.

  Note that the new setting value that has just been set may not necessarily be optimal depending on changes over time of the printing units 12-2, 12-3, and 12-4 for the second and subsequent colors and environmental changes at that time. Accordingly, in step S126, correction setting values for the respective printing units 12-2, 12-3, and 12-4 on the downstream side are calculated in consideration of these aging and environmental changes. The correction setting value is calculated using the correction setting value derivation table 108.

  FIG. 8 shows an example of the correction setting value derivation table 108.

  In FIG. 8, the controllable parts for correcting the new set value set above include the temperature of the conveyance guide, the time from the head to the fixing unit (this is the case where the position of the fixing unit is changed, and the conveyance May change the linear speed), the intensity of the fixing light source, the first liquid (treatment liquid containing a curing initiator and a diffusion inhibitor) and the second liquid (curing main agent and coloring material in each printing unit) The mixing ratio of ink) can be considered.

  For example, in the case of the conveyance guide temperature, the curing is promoted when the temperature of the medium is high. Therefore, in the correction table 106, if the correction coefficient is less than 1, the correction is performed to increase the temperature so that the curing is easy. Make a call. Further, in order to control the time from the head to the fixing unit, there are a case where the position of the fixing lamp 12L is changed and a case where the conveyance speed (linear speed) is changed. For example, in order to make the line thinner, the fixing lamp 12L is moved to shorten the distance from the head to the fixing unit, or to increase the linear velocity.

  Further, when changing the intensity of the fixing light source, for example, the intensity is increased when the line is thinned. In addition, when changing the mixing ratio of the first liquid and the second liquid, for example, when it is desired to make the line thinner, the mixing ratio of the first liquid containing the diffusion preventing agent is increased so that the effect of the diffusion preventing agent is sufficient. Work to prevent diffusion and narrow the line. Conversely, when it is desired to thicken the line, the mixing ratio of the first liquid containing the diffusion inhibitor is decreased.

  In step S128, fixing conditions and ejection conditions based on the correction setting values are set for each of the printing units 12-2, 12-3, and 12-4.

  Thereafter, printing is continued according to the set fixing conditions and ejection conditions.

  That is, in step S130, the processing liquid containing the curing initiator is discharged from the processing liquid head 12S of the headset 12-2HS of the printing unit 12-2 for the second color. In step S132, the coloring material and the main curing agent are added. The second color ink (magenta ink) is ejected from the print head 12M. In step S134, the fixing unit 12-2TC performs fixing according to the fixing conditions set above.

  In step S136, similarly for the third color printing unit 12-3, first, the processing liquid containing the curing initiator is discharged from the processing liquid head 12S of the headset 12-3HS. Thereafter, the processing is continued in the same manner as steps S130 to S134.

  Next, the processing liquid and ink used in this embodiment will be described.

  In the image forming apparatus 10 shown in this embodiment, a curing initiator (polymerization initiator), a diffusion inhibitor, a treatment liquid containing a high-boiling solvent, a curing main agent (polymerizable compound), and a coloring material are used. An ink set composed of each color ink contained is used.

  The polymerizable compound refers to a compound having a function of causing a polymerization reaction and curing by an initiating species such as a radical generated from a polymerization initiator described later.

  It is preferably an addition polymerizable compound having at least one ethylenically unsaturated double bond, and is preferably selected from polyfunctional compounds having at least one terminal ethylenically unsaturated bond, more preferably two or more. Such compound groups are widely known in the industrial field, and these can be used without any particular limitation. These include, for example, those having chemical forms such as monomers, prepolymers, that is, dimers, trimers and oligomers, or mixtures thereof and copolymers thereof.

The polymerizable compound preferably has a polymerizable group such as an acryloyl group, a methacryloyl group, an allyl group, a vinyl group, or an internal double bond group (such as maleic acid) in the molecule, and among them, an acryloyl group and a methacryloyl group. A compound having a group is preferable because it can cause a curing reaction with low energy. Only one type of polymerizable compound may be used in one liquid, or two or more types may be used in combination. As a content rate of the polymeric compound contained in the 2nd liquid containing a coloring agent, the range of 50-99 mass% is preferable in a 2nd liquid, The range of 70-99 mass% is more preferable, 80-99 A range of mass% is more preferred.

  The polymerization initiator refers to a compound that generates an initiation species such as a radical by the energy of light, heat, or both, and initiates and accelerates the polymerization of the polymerizable compound, and is a known thermal polymerization initiator or bond dissociation energy. A compound having a small bond, a photopolymerization initiator and the like can be selected and used.

  Examples of such radical generator include organic halogenated compounds, carbonyl compounds, organic peroxide compounds, azo polymerization initiators, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boric acid compounds, disulfonic acid compounds, oniums. Examples thereof include salt compounds.

  In the ink set used in the present embodiment, a polymerization initiator that cures the polymerizable compound is contained in at least one of the plurality of types of liquids used.

  The content of the polymerization initiator is preferably 0.5 to 20% by mass, and 1 to 15% by mass with respect to the total polymerizable compound used in the ink set from the viewpoints of stability over time, curability, and curing rate. More preferred is 3 to 10% by mass. A polymerization initiator can be used 1 type or in combination of 2 or more types. Further, as long as the effects of the present invention are not impaired, a known sensitizer can be used in combination for the purpose of improving sensitivity.

  The colorant used in the present invention is not particularly limited, and can be appropriately selected from known water-soluble dyes, oil-soluble dyes and pigments as long as they can achieve a hue and color density suitable for the intended use of the ink. be able to. Among these, the liquid constituting the ink for ink jet recording of the present invention is preferably a water-insoluble liquid and does not contain an aqueous solvent from the viewpoint of ink droplet stability and quick drying, and from such a viewpoint It is preferable to use an oil-soluble dye or pigment that is easily dispersed and dissolved in a water-insoluble liquid.

  There is no restriction | limiting in particular in the oil-soluble dye which can be used for this embodiment, Arbitrary things can be used. The content of the dye when using an oil-soluble dye as the colorant is preferably in the range of 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, and more preferably 0.2 to 0.2% in terms of solid content. 6% by mass is particularly preferred. An embodiment in which a pigment is used as the colorant is also preferable from the viewpoint that aggregation easily occurs when a plurality of liquids are mixed.

  As the pigment used in the present embodiment, either an organic pigment or an inorganic pigment can be used, and as the black pigment, a carbon black pigment or the like is preferably exemplified. In general, pigments of three primary colors of black and cyan, magenta, and yellow are used, but pigments having other hues such as red, green, blue, brown, white, gold, silver, etc. The metallic luster pigment, colorless or light-colored extender pigment, and the like can also be used depending on the purpose.

  In addition, particles having silica, alumina, resin, or the like as a core material and having a dye or pigment fixed on the surface, an insoluble raked product of a dye, a colored emulsion, a colored latex, or the like can also be used as a pigment.

  Furthermore, resin-coated pigments can also be used. This is called a microcapsule pigment, and is also available as a commercial product from Dainippon Ink and Chemicals, Toyo Ink, etc.

  The volume average particle diameter of the pigment particles contained in the liquid in the present embodiment is preferably in the range of 30 to 250 nm, more preferably in the range of 50 to 200 nm, from the viewpoint of the balance between optical density and storage stability. is there. Here, the volume average particle diameter of the pigment particles can be measured by a measuring device such as LB-500 (manufactured by HORIBA).

  The content in the case of using a pigment as the colorant is preferably in the range of 0.1% by mass to 20% by mass in terms of solid content in the second liquid, from the viewpoint of optical density and jet stability. More preferably, it is in the range of 1% by mass to 10% by mass. The colorant may be used alone or in combination of two or more. Further, different colorants may be used for each liquid, or the same may be used.

  In the present invention, the diffusion preventing agent refers to the first liquid in order to prevent diffusion and bleeding of the second liquid having the colorant deposited on the first liquid applied to the recording medium. Refers to the substance contained.

  The diffusion inhibitor contains at least one selected from the group consisting of a polymer having an amino group, a polymer having an onium group, a polymer having a nitrogen-containing heterocycle, and a metal compound.

  The said polymer etc. may use single type and may use it in combination of multiple types. “Multiple species” refers to, for example, different genus species that belong to polymers having an amino group but have different structures, or a relationship between a polymer having an amino group and a polymer having an onium group. Including some cases. Further, an amino group, an onium group, a nitrogen-containing heterocycle, and a metal compound may be combined in one molecule.

  The high boiling point organic solvent in the present embodiment refers to an organic solvent having a viscosity at 25 ° C. of 100 mPa · s or less or a viscosity at 60 ° C. of 30 mPa · s or less and a boiling point higher than 100 ° C.

  Here, the “viscosity” used refers to the viscosity obtained using a RE80 viscometer manufactured by Toki Sangyo Co., Ltd. The RE80 type viscometer is a conical rotor / plate type viscometer corresponding to the E type. Measurement is performed at a rotation speed of 10 rpm using the first rotor. However, for those having a viscosity higher than 60 mPa · s, measurement is performed by changing the number of revolutions to 5 rpm, 2.5 rpm, 1 rpm, 0.5 rpm, or the like as necessary.

  “Water solubility” is the saturation concentration of water in a high boiling organic solvent at 25 ° C., and means the mass (g) of water that can be dissolved in 100 g of the high boiling organic solvent at 25 ° C.

  As the usage-amount of the said high boiling point organic solvent, 5-2000 mass% is preferable in conversion of coating amount with respect to the coloring agent to be used, and 10-1000 mass% is more preferable.

  In this embodiment, a storage stabilizer can be added for the purpose of suppressing undesired polymerization during storage of a plurality of types of liquids. The storage stabilizer is preferably used in the same liquid as the polymerizable compound, and it is preferable to use a storage stabilizer that is soluble in the liquid or other coexisting components.

  Examples of the storage stabilizer include quaternary ammonium salts, hydroxyamines, cyclic amides, nitriles, substituted ureas, heterocyclic compounds, organic acids, hydroquinones, hydroquinone monoethers, organic phosphines, copper compounds, and the like. .

  The addition amount of the storage stabilizer is preferably adjusted as appropriate based on the activity of the polymerization initiator used, the polymerizability of the polymerizable compound, and the type of the storage stabilizer. However, the storage stability and the curability of the ink during liquid mixing are preferred. From the standpoint of balance, the amount is preferably 0.005 to 1% by mass in terms of solid content in the liquid, more preferably 0.01 to 0.5% by mass, and still more preferably 0.01 to 0.2% by mass. .

  In the image forming apparatus 10 of the present embodiment, as a means for applying the first liquid onto the recording medium, other means such as coating may be used in addition to the means for ejecting with the ink jet nozzle.

  There is no restriction | limiting in particular as an apparatus used for the said application | coating, A well-known coating apparatus can be suitably selected according to the objective. Examples include air doctor coaters, blade coaters, lot coaters, knife coaters, squeeze coaters, impregnation coaters, reverse roll coaters, transfer roll coaters, gravure coaters, kiss roll coaters, cast coaters, spray coaters, curtain coaters, extrusion coaters, etc. It is done.

In the present embodiment, ultraviolet light, visible light, or the like can be used as an exposure light source for proceeding polymerization of the polymerizable compound. In addition, energy can be applied by radiation other than light, for example, α-ray, γ-ray, X-ray, electron beam, etc. Of these, ultraviolet rays and visible rays are used from the viewpoint of cost and safety. Preferably, ultraviolet rays are used. The amount of energy required for the curing reaction varies depending on the type and content of the polymerization initiator, but is generally about 1 to 500 mJ / cm ² .

  As described above, according to the present embodiment, printing is performed by setting a plurality of fixing conditions and ejection conditions for the first color printing unit. Conditions for detecting the printing result and obtaining the closest result compared with the target value are set as fixing conditions and ejection conditions for the downstream printing unit.

  At this time, the fixing condition is changed in the head width direction, and a detection sensor is provided for each fixing condition. In addition, since a real image is used instead of a test chart, the image recording conditions can be changed in real time, and high-quality image recording can be performed. Furthermore, by having a correction table reflecting changes over time and environmental changes, it is possible to set more optimal conditions.

  Thereby, according to the present embodiment, it is possible to reduce the run cost, improve the productivity, and optimize the fixing conditions and the discharge conditions.

  In the above example, the print result detecting means is provided only for the first color printing unit. However, the same detection means is provided for the second color, and the detection result is used as the fixing condition for the third color printing unit. Alternatively, it may be reflected in the discharge conditions. In this way, a higher effect can be expected. The most upstream printing unit discharges and fixes under preset conditions. However, since the first color uses ink with poor visibility, there is no particular problem in practical use. Further, although the most upstream ink may be insufficiently cured, there is no problem because it is cured at the downstream fixing unit.

  Next, a second embodiment of the present invention will be described.

  This embodiment is a configuration example of an ink jet recording apparatus using a shuttle type one-liquid UV ink (ultraviolet curable ink). That is, in this embodiment, UV irradiation lamps are mounted on the carriage on both sides of an ink head containing color material (including transparency), and the carriage is scanned left and right (in the width direction of the recording paper) along the main scanning axis. By doing so, printing is performed.

  FIG. 9 is an enlarged plan perspective view of the printing unit of the ink jet recording apparatus of the present embodiment.

  As shown in FIG. 9, the recording paper 116 is transported in the direction of arrow B on the belt 133 along the transport path 138. On the belt 133, the first liquid printing unit 112-1 and the second liquid printing unit 112-2 are arranged in this order from the upstream side of the conveyance path 138.

  The first liquid printing unit 112-1 has a print head 112 Y that discharges Y ink at the center on the carriage 115-1, UV irradiation lamps 112 L are arranged on both sides thereof, and further on the downstream side of the conveyance path 138. The print result detecting means 113 is arranged on the same carriage 115-1.

  In the second liquid printing unit 112-2, a print head 112K that discharges K ink, a print head 112C that discharges C ink, and a print head 112M that discharges M ink are arranged in the center on the carriage 115-2. The UV irradiation lamp 112L is arranged on both sides of the lamp.

  The carriage 115-1 of the first liquid printing unit 112-1 and the carriage 115-2 of the second liquid printing unit 112-2 move in the direction of arrow C in the drawing along the scanning guide shaft 139, respectively. The recording paper 116 is scanned and printed.

  In addition, a heater 137 capable of adjusting the temperature of the recording paper (medium) 116 is provided in a portion corresponding to the printing area of the first liquid and the second liquid on the back side of the belt 133 of the conveyance path 138.

  As in the first embodiment described above, after setting a detection area on the recording paper 116, the detection area is divided into a plurality of fixing conditions. For example, as shown in the figure, a detection area 119 is set on the recording paper 116, and the fixing condition is divided into three in the conveyance direction (recording paper longitudinal direction), and the first fixing condition 119a and the second fixing condition are divided therein. 119b and third fixing condition 119c are set.

  In the first embodiment described above, the fixing conditions are divided in the width direction of the recording paper. However, since the present embodiment is a shuttle type, the transport speed is slow, so that the ejection timing can be changed for each scan. Then, it is possible to divide the conditions in the longitudinal direction of the recording paper.

  In the example shown in FIG. 9, the fixing condition is divided into three as 119a to 119c, and the lamp intensity is changed between them.

  As described above, the areas fixed under different fixing conditions are detected by the printing result detection unit 113, and the ejection / fixing conditions of the second printing unit 112-2 are set based on the detection results.

  In the example described above, the lamp intensity is changed as the fixing condition, but the scanning speed and the discharge frequency of the carriages 115-1 and 115-2 are changed to change the time from the shuttle discharge to the fixing. It is also possible. Further, since the transport speed is low in the shuttle type, the temperature of the fixing unit may be changed.

  The image forming apparatus and the image forming method of the present invention have been described in detail above. However, the present invention is not limited to the above examples, and various improvements and modifications are made without departing from the gist of the present invention. Of course it is also good.

1 is an overall configuration diagram showing an outline of a first embodiment of an ink jet recording apparatus as an image forming apparatus according to the present invention. FIG. 2 is an enlarged view of a part of a printing unit of the ink jet recording apparatus of FIG. 1. FIG. 3 is a perspective plan view illustrating a part of a printing unit corresponding to FIG. 2. (A) is a plane perspective view showing the structure of the head, (b) is a cross-sectional view taken along line 4B-4B in FIG. 4 (a). It is a principal block diagram showing the system configuration of the ink jet recording apparatus. 3 is a flowchart illustrating an outline of an image forming method according to an exemplary embodiment. It is explanatory drawing which shows the example of a correction table. It is explanatory drawing which shows the example of a correction setting value derivation | leading-out table. FIG. 6 is a perspective plan view showing an enlarged part of a printing unit of a second embodiment of the image forming apparatus according to the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Inkjet recording device, 12 ... Printing part, 12-1 to 12-4 ... Printing unit, 12Y, 12M, 12C, 12K ... Print head, 12S ... Treatment liquid head, 12-1HS-12-4HS ... Headset, 12-1TC to 12-4TC: fixing unit, 12G ... guide rail, 12L ... fixing lamp, 13 ... printing result detecting means, 14 ... ink storage / loading unit, 16 ... recording paper, 18 ... paper feeding unit, 20 ... decal Processing unit 22 ... Conveying unit 24 ... Print detection unit 26 ... Discharge unit 28 ... Cutter 30 ... Heating drum 31, 32 ... Roller 33 ... Belt 34 ... Adsorption chamber 35 ... Fan 36 ... Belt cleaning section, 37 ... heater, 40 ... heating fan, 42 ... post-drying section, 44 ... heating / pressurizing section, 45 ... pressure roller, 48 ... cutter, 50 ... head, 51 ... , 52 ... pressure chamber, 53 ... droplet ejection element, 56 ... diaphragm (common electrode), 57 ... individual electrode, 58 ... piezoelectric element, 70 ... communication interface, 72 ... system controller, 74 ... image memory, 76 ... Motor driver, 78 ... heater driver, 80 ... print control unit, 82 ... image buffer memory, 84 ... print head driver, 86 ... treatment liquid head driver, 89 ... heater, 92 ... host computer, 94 ... motor, 95 ... first Discharge / fixing condition setting unit, 96... Dot diameter calculation unit, 98... Dot diameter comparison unit, 100... Second discharge and fixing condition setting unit, 102. Correction table 108... Correction setting value derivation table 110 110 Memory

Claims (9)

An image forming apparatus that prints an image on a recording medium while conveying the recording medium to a liquid ejection head,
A plurality of printing units disposed along the conveyance path of the recording medium, each having a liquid ejection head and fixing means;
Detection area setting means for setting a plurality of detection areas in an image printed on the recording medium;
A first discharge capable of setting a plurality of discharge conditions of the liquid discharge head and fixing conditions of the fixing unit of a predetermined first print unit among the plurality of print units corresponding to the plurality of detection areas.・ Fixing condition setting means,
A print result detecting means for detecting a print result printed in each of the plurality of detection areas;
Based on the detection result of the print result detection unit, the discharge condition of the liquid discharge head and the fixing condition of the fixing unit of the print unit disposed downstream of the first print unit in the conveyance direction of the recording medium. Second discharge / fixing condition setting means for setting,
An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the liquid discharge head is a line type head.   The image forming apparatus according to claim 1, wherein the printing unit includes a liquid discharge head that discharges a processing liquid and a liquid discharge head that discharges ink.   The image forming apparatus according to claim 3, wherein the liquid ejection head of the first printing unit ejects ink having the lowest visibility among the plurality of inks ejected by the plurality of printing units. apparatus.   The image forming apparatus according to claim 1, wherein the fixing unit of the first printing unit can set a plurality of different fixing conditions in a width direction of the recording medium conveyance path.   The image forming apparatus according to claim 1, wherein a plurality of the print result detection units are installed corresponding to the plurality of fixing conditions.   The discharge conditions and the fixing conditions set for the print unit arranged on the downstream side in the transport direction of the recording medium from the first print unit according to the detection result are considered in consideration of changes over time and environmental changes. The image forming apparatus according to claim 1, further comprising a table for correction.   The image forming apparatus according to claim 3, wherein the treatment liquid includes a curing initiator, and the ink includes a color material and a curing main agent. A plurality of printing units each having a liquid ejection head and a fixing unit are arranged along the recording medium conveyance path, and at least one ejection condition is applied to the liquid ejection head of a predetermined first printing unit among the plurality of printing units. And then fixing the image by at least one fixing condition by the fixing unit of the first printing unit to form an image,
A print result in a detection area designated in advance in the formed image is detected by a detection means installed immediately after a fixing means of the first print unit;
The discharge condition of the liquid discharge head and the fixing condition of the fixing unit of the printing unit arranged downstream of the first printing unit in the recording medium conveyance direction are set according to the detection result. An image forming method.

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