JP2013103384A - Printer and printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the variation in printing image quality before and after splices in the printing onto a continuous sheet which has splices.SOLUTION: When a splice is sensed during printing onto the continuous sheet, at least one of the temperature and the humidity in the printing section is adjusted in response to the characteristics of the following sheet region which follows the splice.

Description

  The present invention relates to a printing apparatus that performs printing using a roll-shaped continuous sheet.

  A roll-like continuous sheet is used for a large amount of prints such as lab prints. When manufacturing a roll-like continuous sheet, from the viewpoint of improving the manufacturing yield, the ends of a plurality of continuous sheets that are less than the required length are joined together with a fixing material (hereinafter referred to as a tape) such as a splicing tape. The roll may have a required length. This roll-shaped continuous sheet has one or more splices (joining portions) joined by tape at random positions.

  In the apparatus disclosed in Patent Document 1, the position of the splice is detected by detecting the tape using an optical sensor, and the area including the splice is controlled so as not to be printed as an unrecordable area.

JP 2001-239715 A

  When printing high-quality photographic images, etc., the sheet conveyance characteristics change depending on the type of sheet used (paper type, paper quality, paper thickness, etc.), and there are differences in the sheet conveyance amount and conveyance speed. And appear as a difference in print image quality. For this reason, if the conveyance characteristics of the front and rear sheets joined by the splice of the continuous sheet are different, images having different image quality such as color and graininess can be obtained before and after the splice. If the print image quality changes in the middle of a plurality of pages of a single printed matter such as a photo album, the viewer is greatly discomforted. Therefore, it is desired that a series of images sequentially printed on a continuous sheet maintain the same print image quality.

  However, Patent Document 1 does not disclose any technique for recognizing and solving such problems. The present invention has been made based on recognition of the above-described problems. An object of the present invention is to provide a technique for reducing a change in print image quality before and after a splice in printing on a continuous sheet having a splice.

  The printing apparatus of the present invention includes a conveyance unit that conveys continuous sheets, a print unit that prints an image on a sheet conveyed by the conveyance unit, and a detection unit that detects a splice of the sheet conveyed by the conveyance unit. An adjustment unit that adjusts at least one of the temperature and humidity of the print unit; and if the splice is detected by the detection unit, at least one of the temperature and the humidity depends on the characteristics of the subsequent sheet area following the splice. And a control unit that controls the adjustment unit so as to make adjustments.

  According to the present invention, when a splice is detected during printing on a continuous sheet, at least one of temperature and humidity in the printing unit is adjusted according to the characteristics of the subsequent sheet area following the splice, so printing before and after the splice is performed. The change in image quality can be reduced.

Overall appearance of printing apparatus of embodiment Configuration diagram showing the internal configuration of the print unit Cross section of continuous sheet splice Flow chart showing overall sequence of printing operation The figure which shows each state of the continuous sheet which is conveyed

  Hereinafter, an embodiment of a printing apparatus using an inkjet method will be described. The printing device of this example uses long and continuous sheets (continuous sheets longer than the length of repeated printing units (one page or unit image) in the transport direction), and supports both single-sided printing and double-sided printing. High-speed line printer. For example, it is suitable for the field of printing a large number of sheets in a print laboratory or the like.

  FIG. 1 is an overall external view of a printing apparatus according to an embodiment. The printing apparatus generally includes a printer main body unit 1, a sheet supply unit 2, a sheet winding unit 3, and a control unit 6. The sheet supply unit 2 holds the roll sheet 4 wound in a roll shape, and supplies the continuous sheet to the printer main unit 1 while pulling out the continuous sheet from the roll. The printer body 1 sequentially prints a plurality of images on a continuous sheet. The printed continuous sheet is wound up as a roll sheet 5 by the sheet winding unit 3. The control unit 6 includes a controller, a memory, and various I / O interfaces, and controls the entire printing apparatus. The control unit 6 may be built in the printing apparatus itself, or may be an external host computer connected to the printing apparatus. Note that at an arbitrary position in the sheet conveyance path, the side close to the sheet supply unit 2 is referred to as “upstream”, and the opposite side is referred to as “downstream”.

  If the sheet | seat hold | maintained at the sheet supply part 2 is a continuous sheet, it will not be restricted to what was wound by roll shape. For example, the continuous sheet | seat provided with the perforation for every unit length may be return | folded and laminated | stacked for every perforation, and may be accommodated in the sheet | seat supply part 2. FIG.

  As shown in FIG. 3, the continuous sheet used here has one or more splices (joining portions) joined by tape or glue at random positions. The continuous sheet has a splice in advance when the roll is manufactured. In addition, when the continuous sheet of one roll is used up, the user may connect the sheets and continue printing as a new continuous sheet. In this case, a splice is formed in the middle of the continuous sheet.

  In FIG. 3, a preceding continuous sheet (preceding sheet region 103) and a succeeding continuous sheet (following sheet region 102) are joined together by a splice to form a continuous continuous sheet S. In this example, a part of the preceding sheet 26 and the succeeding sheet region 102 are overlapped and glued together, and the tape 101 is further stuck thereon. The part where the tape 101 is affixed is a splice. Due to the overlap between the sheets and the thickness of the tape 101, a level difference larger than the original sheet thickness is formed only in that portion.

  2 is a configuration diagram showing the internal configuration of the printer main body 1. FIG. 2 (a) is a top view, FIG. 2 (b) is a side view, and FIG. 2 (c) is a main member above the sheet. It is the bottom view which looked at from the bottom. The continuous sheet S supplied from the sheet supply unit 2 to the printer body 1 is conveyed in the direction of arrow A in the printing unit.

  As a sheet conveyance mechanism (conveyance unit) in the printing unit, a pair of upstream conveyance rollers including a conveyance roller 15 and a pinch roller 16 that is driven to rotate, and a pair of downstream conveyance rollers including a conveyance roller 17 and a pinch roller 18 that is driven to rotate. Is provided. The platen 19 guides and holds the lower surface of the continuous sheet at the recording position.

  The print unit 10 includes a plurality of inkjet printheads 14. Each print print head has a line type print head in which an inkjet nozzle row is formed in a range that covers the maximum print width expected to be used. The ink nozzle row may be either one in which unit nozzle chips are formed over the entire width direction by a regular arrangement such as a staggered arrangement, or one row formed over the entire width direction. As the inkjet method, a method using a heating element, a method using a piezo element, a method using an electrostatic element, a method using a MEMS element, or the like can be adopted.

  Each color ink is supplied from an ink tank to each print head via an ink tube. In this example, the printing unit 10 includes three parts, a cyan head 11 for cyan ink, a magenta head 12 for magenta ink, and a yellow head 13 for yellow color. 2C, the nozzle row 11a is formed on the discharge surface of the cyan head 11, the nozzle row 12a is formed on the discharge surface of the magenta head 12, and the nozzle row 13a is formed on the discharge surface of the yellow head 13, respectively. Has been. Note that the number of colors and the number of print heads are not limited to three, and may be larger or smaller.

  An ink tube is connected to each print head, and ink is supplied from an ink tank (not shown). Each print head may be a unit integrated with an ink tank that stores the corresponding color ink. Each print head is integrally held by a head holder (not shown).

  In the printing unit 10, the temperature and humidity of the space where the nozzles of the print head 14 are exposed are managed. Specifically, it has a gas supply mechanism (adjustment unit) having a supply unit 50 provided upstream of the most upstream print head 11 and a recovery unit 51 provided downstream of the most downstream print head 13. A gas whose temperature and humidity are controlled is introduced from the supply unit 50 (arrow B in the figure), and the gas flows from upstream to downstream in the space between the sheet S or the platen 19 and the nozzle surface of the print head. Flows. The gas flowing through the space is recovered from the recovery unit 51 (arrow C in the figure). As a result, the nozzles of each print head are exposed to an appropriate humidity space, and nozzle clogging and ejection failure due to ink drying are reduced. In order to change the capability of the gas supply mechanism, the temperature and / or humidity of the supplied gas is controlled by the control unit 6. A specific control method will be described later.

  A reading unit 40 that reads a pattern or an image on a sheet is provided further downstream of the printing unit 10. The reading unit 40 includes a scanner 41 and a conveyance roller 44. The scanner 41 is for reading an image for conveyance adjustment and an inspection image printed on a continuous sheet by the printing unit 10. As shown in FIG. 2C, the scanner 41 includes a light emitting unit including light emitting elements 41a of RGB three colors and a light receiving unit including an image sensor 41b (CCD image sensor or CMOS image sensor). The white reference plate 42 is disposed to face the reading position of the image sensor 41b with the sheet interposed therebetween. The white reference plate 42 is a self-colored plate and is used for color calibration of the image sensor 41b.

  A detection unit 20 for detecting a splice (tape 101) of a continuous sheet optically in a non-contact manner is provided upstream of the print unit 10 from above the sheet surface. The detection unit 20 includes a sensor unit 21, two guide roller pairs 22 that rotate while sandwiching the sheet upstream and downstream of the sensor unit 21, and a platen that supports the back surface of the sheet at the inspection position. The sensor unit 21 includes a light emitting unit that irradiates light on the sheet surface obliquely and an array sensor that detects reflected light. Both the preceding sheet area 103 and the succeeding sheet area 102 are glossy white and have a high reflectance. On the other hand, the surface of the tape 101 is black and has been subjected to a mat treatment, and has a low light reflectance. Using the difference in reflectance, the sensor unit 21 detects that the splice tape 101 has passed through the sensor detection position.

  FIG. 4 is a flowchart showing the entire sequence of the printing operation controlled by the control unit 6. In step S101, sequential printing of a plurality of unit images is started on a continuous sheet. In step S102, the splicing of the continuous sheet is detected by the sensor unit 21 during printing. FIG. 5A shows the state at the moment when a splice is detected. If a splice is detected (Yes), the process proceeds to step S103, and if not detected (No), the process proceeds to step S107.

  In step S103, the unit image is continuously printed until the detected splice reaches the print position of the most upstream print head of the print unit 10, and as many unit images as possible are printed. The length of the conveyance path from the detection position of the sensor unit 21 to the print position of the most upstream print head 11 is determined by design. The number of unit images that can be printed in the area of the length can be calculated from the length of the unit image in the transport direction. FIG. 5B shows a state when the splice comes immediately before the print area.

  In step S104, the area including the splice is set as a print prohibition area, and when this interval passes the print position, printing is skipped without performing printing. The print prohibition area is blank without ink.

  In step S105, an inspection pattern for temperature adjustment and humidity adjustment of the nozzle exposure space of the printing unit 10 is sequentially printed at the head of the succeeding sheet region 102 following the splice 100 using the print heads of the respective colors of the printing unit 10. . FIG. 5C shows a state in which an inspection pattern is being printed.

  In step S106, until the printed inspection pattern reaches the reading position of the scanner 41, the area following the inspection pattern is not printed as a blank area, and the sheet conveyance is continued. In step S106, the length of the blank area that is generated before the next image is printed after being skipped is determined by the sum of the two lengths. The first is the length of the transport path from the print position of the print head 13 at the most downstream side of the print unit 10 to the reading position (the most downstream position) of the scanner 41 of the reading unit 40. The second is the length of the sheet conveyed during the period required for the adjustment performed in step S108.

  In step S107, the inspection pattern formed on the sheet is read by the scanner 41 of the reading unit 40 to acquire read data. FIG. 5D shows a state in which the inspection pattern is being read.

  In step S108, based on the read data acquired in step S107, the control unit 6 controls the temperature of the nozzle exposure space of the printing unit 10 and / or the humidity adjustment of the gas generated by the gas supply mechanism. Control temperature and humidity. In this way, the control unit 6 predicts the timing at which the splice detected by the detection unit 20 passes through the printing unit 10 and the timing through which the reading unit 40 passes, and adjusts the air conditioning of the printing unit 10 according to these predictions. This is what is controlled.

  In step S109, printing of the unit image is resumed after the adjustment in step S108. In step S110, it is determined whether printing of the predetermined number of unit images has been completed (Yes) or not (No). If the determination is No, the process returns to step S101 and the process is repeated. If the determination is Yes, the sequence ends.

  Note that the gas supply mechanism (adjustment unit) may be adjusted according to the characteristics of the preceding sheet area, similarly to steps S105 to S108, before starting the printing of the unit image in step S101. That is, the control unit 6 controls the adjustment unit to adjust the preceding sheet area before the splice according to the characteristics of the preceding sheet area.

  Here, in step S108, at least one of the density and color of the inspection pattern is determined from the read data. In image formation in the print unit 10, an inspection pattern is determined depending on characteristics such as ink penetration speed, ink absorption amount, moisture hygroscopicity of the sheet to be used, ink placement amount that matches the sheet characteristics, and temperature and humidity in the print unit 10. Concentration and color change. Therefore, the density and color of the actual inspection pattern are detected, and the temperature and humidity of the gas supplied to the space are adjusted so that the desired density and color pattern are printed regardless of the sheet characteristics. A sensor for detecting the moisture content of the sheet may be provided downstream of the print unit, and the temperature and humidity of the gas supplied to the space may be adjusted according to the detected moisture content.

  In the adjustment in step S108, the control unit 6 performs PID control. In PID control, a proportional operation (P operation) for outputting an output proportional to the deviation between the current value and the set value, an output proportional to the integral of the deviation (I operation), and an output proportional to the differential of the deviation are output. The sum of the differential action (D action) is output and controlled toward the control target value. In PID control, learned data is accumulated. When the detection unit 20 detects a splice, it is preferable to reset the control data learned by the PID control of the preceding sheet area so far and newly start the PID control in the subsequent sheet area.

  According to the present embodiment, when a splice is detected during printing on a continuous sheet, at least one of temperature and humidity in the print unit is adjusted according to the characteristics of the subsequent sheet area following the splice. The change in print image quality can be reduced. In addition, since the energy consumption of the gas supply mechanism, which accounts for a large proportion of the power consumption in the printing apparatus, is suppressed from being increased, energy saving of the entire printing apparatus can be realized.

  In the above-described example, information related to characteristics such as moisture absorption of the succeeding sheet region 102 is acquired using the inspection pattern. However, the sheet information can be acquired by other methods. For example, information relating to the succeeding sheet region 102 may be recorded or held on the sheet itself, and the sheet information may be read and adjusted.

  FIG. 2A shows an example in which the code pattern 104 is recorded in advance immediately after the tape 101 of the splice of the sheet S (the leading portion of the subsequent sheet area 102). The code pattern is recorded on the sheet by the manufacturer when the roll sheet is manufactured. By reading the code pattern 104 with the sensor unit 21, sheet information regarding the subsequent sheet region 102 can be acquired. The code pattern 104 records information (sheet type, sheet characteristics, sheet thickness, etc.) regarding characteristics such as hygroscopicity of the sheet in the subsequent sheet area 102 in the form of a barcode. The code pattern 104 is not limited to the succeeding sheet area 102 but may be recorded on the tape 101 or the trailing edge of the preceding sheet area 103. The code may be read by a magnetic sensor as a magnetic pattern instead of an optical pattern. Alternatively, an electronic mark such as an IC tag may be embedded in the sheet in the same area as the code pattern 104 to hold the sheet information electronically, and the information may be read in a non-contact manner with an IC tag reader.

DESCRIPTION OF SYMBOLS 10 Print part 14 Print head 20 Detection part 21 Sensor unit 40 Reading part 41 Scanner 50 Supply part 51 Recovery part 100 Splice 101 Tape 102 Predecessor sheet 103 Subsequent sheet 104 Code pattern

Claims (12)

A transport unit for transporting continuous sheets;
A print unit for printing an image on a sheet conveyed by the conveyance unit;
A detection unit for detecting a splice of a sheet conveyed by the conveyance unit;
An adjustment unit for adjusting at least one of temperature and humidity of the print unit;
A controller that controls the adjustment unit to adjust at least one of the temperature and the humidity according to characteristics of a subsequent sheet region following the splice when the detection unit detects the splice;
A printing apparatus comprising: A reading unit that reads an image printed by the printing unit;
The printing apparatus according to claim 1, wherein the characteristic is acquired based on data acquired by reading the inspection pattern printed by the printing unit by the reading unit.   The printing apparatus according to claim 2, wherein the characteristic is a sheet characteristic determined based on at least one of a density and a color of an image read by the reading unit. Information on the characteristics is recorded or held on the sheet,
The printing apparatus according to claim 1, wherein the information related to the characteristic is acquired by reading the information by the detection unit.   The printing apparatus according to claim 4, wherein the characteristic is information relating to a sheet type.   The printing apparatus according to claim 1, further comprising a unit that detects a moisture content of the sheet, wherein the control unit performs the adjustment according to the acquired moisture content.   The adjusting unit generates a gas whose temperature and humidity are controlled and supplies the gas to a space where the nozzles of the print head of the printing unit are exposed, and the control unit controls the temperature and humidity of the supplied gas. The printing apparatus according to claim 1, wherein the printing apparatus is a printing apparatus.   The said control part adjusts the said adjustment part according to the characteristic of the said preceding sheet area | region in the preceding sheet area | region before the said splice, The one of Claim 1 to 6 characterized by the above-mentioned. Printing device.   9. The control unit according to claim 1, wherein the control unit predicts a timing at which the splice detected by the detection unit passes through the print unit, and performs the adjustment according to the prediction. The printing apparatus as described in.   10. The control unit according to claim 1, wherein the control unit performs the adjustment by PID control, and resets the learned control data when the detection unit detects the splice. 11. Printing device. When the splice is detected by the detection unit, an inspection pattern is printed on the subsequent sheet area, and is not printed on an area following the inspection pattern, and is conveyed as a blank area and read by the reading unit,
The printing apparatus according to claim 2, wherein the length of the blank area is determined by a sum of a length from the printing unit to the reading unit and a length in which a sheet is conveyed in a period required for the adjustment. . Conveying a continuous sheet;
Printing an image on the conveyed sheet by a printing unit;
Detecting a splice of the conveyed sheet;
Adjusting at least one of temperature and humidity of the print part;
If the splice is detected, adjusting at least one of the temperature and the humidity according to the characteristics of the subsequent sheet area following the splice;
A printing method characterized by comprising:

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