JP2012153150A - Printing device and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for avoiding printing to a splice and for carrying out image printing following the splice well.SOLUTION: If an improper area not being proper for printing is on a continuous sheet, an image is not printed to an unprintable area including the improper area, and then ink is ejected from a print head to the continuous sheet for maintenance of the print head before print of the image is resumed onto the rear of the unprintable area.

Description

  The present invention relates to a printing apparatus that performs printing using a 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 splice parts (joining parts) joined by tape at random positions.

  In the apparatus disclosed in Patent Document 1, the position of the splice part is detected by detecting the tape using an optical sensor, and the area including the splice part is controlled as a non-recordable area. Further, if one image of a large size (second print size) cannot fit in the area before the detected splice part, a smaller size (first print size) image is blanked first. The order of images to be printed is changed so that the images are printed.

JP 2001-239715 A

  In an inkjet print head, a nozzle that is not used frequently may cause ink ejection failure. In order to prevent the occurrence of such undischarge nozzles, regular head maintenance is required. Even when multiple images are printed sequentially on a continuous sheet, every time a predetermined number of images are printed, ink is ejected from all nozzles to form a maintenance pattern on the sheet, and periodic head maintenance is performed. It is desirable to do.

  However, in the apparatus described in Patent Document 1, no consideration is given to head maintenance, and the splice unit is simply set as a non-recordable area. For the print head, the non-recordable area is a pause period during which all nozzles do not discharge ink, and thus there is a possibility that undischargeable nozzles may occur due to ink drying or the like during that period. When a discharge failure nozzle occurs, an image defect of a print that follows the non-recordable area occurs.

  The present invention has been made based on the recognition of the above-mentioned problems. An object of the present invention is to avoid printing in an unsuitable area and printing an image behind the unsuitable area when a plurality of images are sequentially printed on a continuous sheet having an unsuitable area unsuitable for image printing such as a splice portion. The provision of a technique that can be performed well.

  The present invention is a printing apparatus that sequentially prints a plurality of images by ejecting ink from a print head onto a continuous sheet, the means for specifying an unsuitable area that is not suitable for printing on the continuous sheet; Once the area has been identified, the image is not printed on the print prohibition area including the unsuitable area, and then the print head is maintained before resuming image printing after the print prohibition area. And a means for controlling the ink to be ejected from the print head to the continuous sheet.

  According to the present invention, since the printing of the image is resumed after the printing to the inappropriate area such as the splice portion is avoided and the print head is maintained, the image printing after the inappropriate area can be favorably performed.

Schematic showing the internal configuration of the printing device Block diagram of control unit Flow chart showing overall sequence of printing operation The figure which shows the arrangement order of the print order according to the print command table The figure for explaining the procedure which corrects the arrangement order of the print command table Flow chart showing processing procedure for correction of print command table FIG. 4 shows a variation of FIG. FIG. 5 shows a modification of FIG. The flowchart which shows the process sequence in a modification.

  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. In this specification, even if a plurality of small images, characters, and blanks are mixed in the area of one print unit (one page), what is included in the area is collectively referred to as one unit image. . That is, the unit image means one print unit (one page) when a plurality of pages are sequentially printed on a continuous sheet. In some cases, an image is simply referred to as a unit image. The length of the unit image varies depending on the image size to be printed. For example, the length in the sheet conveyance direction is 135 mm for the L size photograph, and the length in the sheet conveyance direction is 297 mm for the A4 size. The present invention can be widely applied to printing apparatuses that require drying using ink, such as printers, multifunction printers, copying machines, facsimile machines, and various device manufacturing apparatuses.

  FIG. 1 is a schematic cross-sectional view showing the internal configuration of the printing apparatus. The printing apparatus according to the present embodiment is capable of duplex printing on the first surface of the sheet and the second surface on the back side of the first surface, using the sheet wound in a roll shape. Inside the printing apparatus, there are roughly a sheet supply unit 1, a decurling unit 2, a skew correction unit 3, a printing unit 4, an inspection unit 5, a cutter unit 6, an information recording unit 7, a drying unit 8, a reversing unit 9, and a discharge unit. Each unit includes a transport unit 10, a sorter unit 11, a discharge unit 12, and a control unit 13. The discharge unit 12 includes a sorter unit 11 and performs a discharge process. A sheet is conveyed by a conveyance mechanism including a roller pair and a belt along a sheet conveyance path indicated by a solid line in the drawing, and is processed in each unit. Note that at an arbitrary position in the sheet conveyance path, the side close to the sheet supply unit 1 is referred to as “upstream”, and the opposite side is referred to as “downstream”.

  The sheet supply unit 1 is a unit for holding and supplying a continuous sheet wound in a roll shape. The sheet supply unit 1 can store two rolls R <b> 1 and R <b> 2, and is configured to selectively pull out and supply a sheet. The number of rolls that can be stored is not limited to two, and one or three or more rolls may be stored. Moreover, if it is a continuous sheet | seat, 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 1. FIG.

  The continuous sheet used here has one or more splice parts (joining parts) joined by tape or glue at random positions. The splice portion is an inappropriate area that is not suitable for image printing. A splice sensor 17 is provided in the vicinity of the outlet of the sheet supply unit 1 to detect the splice unit of the continuous sheet supplied from the sheet supply unit 1. Details of the splice sensor 17 (detection unit) will be described later.

  The decurling unit 2 is a unit that reduces curling (warping) of the sheet supplied from the sheet supply unit 1. The decurling unit 2 uses two pinch rollers for one driving roller, and curls the sheet by curving and passing the sheet so as to give the curl in the opposite direction, thereby reducing the curl.

  The skew correction unit 3 is a unit that corrects skew (inclination with respect to the original traveling direction) of the sheet that has passed through the decurling unit 2. The sheet skew is corrected by pressing the sheet end on the reference side against the guide member. In the skew correction unit 3, a loop is formed in the conveyed sheet.

  The printing unit 4 is a sheet processing unit that forms an image by performing a printing process on the conveyed sheet from above with the print head 14. That is, the print unit 4 is a processing unit that performs a predetermined process on the sheet. The printing unit 4 also includes a plurality of conveyance rollers that convey the sheet. The print head 14 has a line type print head in which an inkjet nozzle row is formed in a range that covers the maximum width of a sheet that is supposed to be used. The print head 14 has a plurality of print heads arranged in parallel along the transport direction. In this example, there are seven print heads corresponding to seven colors of C (cyan), M (magenta), Y (yellow), LC (light cyan), LM (light magenta), G (gray), and K (black). . The number of colors and the number of print heads are not limited to seven. 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 the ink tank to the print head 14 via an ink tube.

  The inspection unit 5 optically reads the inspection pattern or image printed on the sheet by the printing unit 4 using a scanner, and inspects the nozzle state of the print head, the sheet conveyance state, the image position, etc., and the image is printed correctly. This is a unit for determining whether or not. The scanner has a CCD image sensor and a CMOS image sensor.

  The cutter unit 6 is a unit including a mechanical cutter 18 that cuts a printed sheet into a predetermined length. The cutter unit 6 further includes a cut mark sensor for optically detecting a cut mark recorded on the sheet and a plurality of conveying rollers for sending the sheet to the next process. A trash can 19 is provided in the vicinity of the cutter unit 6. The trash box 19 accommodates small sheet pieces that are cut off by the cutter unit 6 and discharged as trash. The cutter unit 6 is provided with a sorting mechanism for discharging the cut sheet to the trash box 19 or shifting it to the original conveyance path.

  The information recording unit 7 is a unit that records print information (unique information) such as a print serial number and date in a non-print area of the cut sheet. Recording is performed by printing characters and codes using an inkjet method, a thermal transfer method, or the like.

  The drying unit 8 is a unit for heating the sheet printed by the printing unit 4 and drying the applied ink in a short time. Inside the drying unit 8, hot air is applied at least from the lower surface side to the passing sheet to dry the ink application surface. The drying method is not limited to the method of applying hot air, and may be a method of irradiating the sheet surface with electromagnetic waves (such as ultraviolet rays and infrared rays).

  The sheet conveyance path from the sheet supply unit 1 to the drying unit 8 is referred to as a first path. The first path has a U-turn shape between the printing unit 4 and the drying unit 8, and the cutter unit 6 is located in the middle of the U-turn shape.

  The reversing unit 9 is a unit for temporarily winding a continuous sheet on which front surface printing has been completed when performing double-sided printing, and reversing the front and back. The reversing unit 9 is a path (loop path) (referred to as a second path) from the drying unit 8 through the decurling unit 2 to the printing unit 4 for supplying the sheet that has passed through the drying unit 8 to the printing unit 4 again. It is provided on the way. The reversing unit 9 includes a winding rotary body (drum) that rotates to wind the sheet. The continuous sheet that has been printed on the surface and has not been cut is temporarily wound around the winding rotary member. When the winding is completed, the winding rotary member rotates in the reverse direction, and the wound sheet is fed out in the reverse order to the winding and supplied to the decurling unit 2 and sent to the printing unit 4. Since this sheet is turned upside down, the printing unit 4 can print on the back side. If the sheet supply unit 1 is a first sheet supply unit, the reversing unit 9 can be regarded as a second sheet supply unit. More specific operation of duplex printing will be described later.

  The discharge conveyance unit 10 is a unit for conveying the sheet cut by the cutter unit 6 and dried by the drying unit 8 and delivering the sheet to the sorter unit 11. The discharge conveyance unit 10 is provided in a route (referred to as a third route) different from the second route in which the reversing unit 9 is provided. A path having a movable flapper at a branch position (referred to as “discharge branch position”) in order to selectively guide the sheet conveyed on the first path to one of the second path and the third path. A switching mechanism is provided.

  The discharge unit 12 including the sorter unit 11 is provided on the side of the sheet supply unit 1 and at the end of the third path. The sorter unit 11 is a unit for sorting printed sheets for each group as necessary. The sorted sheets are discharged to a plurality of trays that the discharge unit 12 has. In this way, the third path has a layout that passes below the sheet supply unit 1 and discharges the sheet to the opposite side of the printing unit 4 and the drying unit 8 across the sheet supply unit 1.

  As described above, the sheet supply unit 1 to the drying unit 8 are sequentially provided in the first path. The tip of the drying unit 8 is branched into a second route and a third route, the reversing unit 9 is provided in the middle of the second route, and the tip of the reversing unit 9 joins the first route. A discharge part 12 is provided at the end of the third path.

  The control unit 13 is a unit that controls each unit of the entire printing apparatus. The control unit 13 includes a CPU, a storage device, a controller including various control units, an external interface, and an operation unit 15 that is input and output by a user. The operation of the printing apparatus is controlled based on a command from a host device 16 such as a controller or a host computer connected to the controller via an external interface.

  FIG. 2 is a block diagram showing the concept of the control unit 13. A controller (range enclosed by a broken line) included in the control unit 13 includes a CPU 201, a ROM 202, a RAM 203, an HDD 204, an image processing unit 207, an engine control unit 208, and an individual unit control unit 209. A CPU 201 (central processing unit) controls the operation of each unit of the printing apparatus in an integrated manner. The ROM 202 stores programs executed by the CPU 201 and fixed data necessary for various operations of the printing apparatus. The RAM 203 is used as a work area for the CPU 201, used as a temporary storage area for various received data, and stores various setting data. The HDD 204 (hard disk) can store and read programs executed by the CPU 201, print data, and setting information necessary for various operations of the printing apparatus. The operation unit 15 is an input / output interface with a user, and includes an input unit such as a hard key and a touch panel, and an output unit such as a display for presenting information and a sound generator.

  A dedicated processing unit is provided for units that require high-speed data processing. An image processing unit 207 performs image processing of print data handled by the printing apparatus. The color space (for example, YCbCr) of the input image data is converted into a standard RGB color space (for example, sRGB). Various image processing such as resolution conversion, image analysis, and image correction is performed on the image data as necessary. Print data obtained by these image processes is stored in the RAM 203 or the HDD 204. The engine control unit 208 performs drive control of the print head 14 of the print unit 4 according to print data based on a control command received from the CPU 201 or the like. The engine control unit 208 also controls the transport mechanism of each unit in the printing apparatus. The individual unit control unit 209 includes a sheet supply unit 1, a decurling unit 2, a skew correction unit 3, an inspection unit 5, a cutter unit 6, an information recording unit 7, a drying unit 8, a reversing unit 9, a discharge conveyance unit 10, and a sorter unit. 11 and a sub-controller for individually controlling each unit of the discharge unit 12. The individual unit control unit 209 controls the operation of each unit based on a command from the CPU 201. The external interface 205 is an interface (I / F) for connecting the controller to the host device 16 and is a local I / F or a network I / F. The above components are connected by the system bus 210.

  The host device 16 is a device serving as a supply source of image data for causing the printing apparatus to perform printing. The host device 16 may be a general-purpose or dedicated computer, or a dedicated image device such as an image capture having an image reader unit, a digital camera, or a photo storage. When the host device 16 is a computer, an OS, application software for generating image data, and a printer driver for the printing device are installed in a storage device included in the computer. Note that it is not essential to implement all of the above processing by software, and a part or all of the processing may be realized by hardware.

  Next, the basic operation during printing will be described. Since the printing operation differs between the single-sided printing mode and the double-sided printing mode, each will be described.

  In the single-sided print mode, the sheet supplied from the sheet supply unit 1 and processed by the decurling unit 2 and the skew correction unit 3 is printed on the front surface (first surface) in the printing unit 4. An image (unit image) having a predetermined unit length in the conveyance direction is sequentially printed on a long continuous sheet to form a plurality of images side by side. The printed sheet passes through the inspection unit 5 and is cut for each unit image in the cutter unit 6. The cut sheet is recorded with print information on the back side of the sheet by the information recording unit 7 as necessary. Then, the cut sheets are conveyed one by one to the drying unit 8 and dried. Thereafter, the sheet is sequentially discharged and stacked on the discharge unit 12 of the sorter unit 11 via the discharge conveyance unit 10. On the other hand, the sheet left on the print unit 4 side by cutting the last unit image is sent back to the sheet supply unit 1, and the sheet is wound on the roll R1 or R2. Thus, in single-sided printing, the sheet passes through the first path and the third path and is processed, and does not pass through the second path.

  On the other hand, in the double-sided print mode, the back side (second side) print sequence is executed after the front side (first side) print sequence. In the first front surface print sequence, the operation in each unit from the sheet supply unit 1 to the inspection unit 5 is the same as the one-sided printing operation described above. The cutter unit 6 is conveyed to the drying unit 8 as a continuous sheet without performing a cutting operation. After the surface ink is dried by the drying unit 8, the sheet is guided not to the path on the discharge conveyance unit 10 (third path) but to the path on the reversing unit 9 (second path). In the second path, the sheet is wound around the winding rotary body of the reversing unit 9 that rotates in the forward direction (counterclockwise direction in the drawing). When all of the scheduled printing on the surface is completed in the printing unit 4, the trailing edge of the print area of the continuous sheet is cut by the cutter unit 6. With reference to the cutting position, the continuous sheet on the downstream side (printed side) in the conveying direction is wound up to the rear end (cutting position) of the sheet by the reversing unit 9 through the drying unit 8. On the other hand, at the same time as the winding by the reversing unit 9, the continuous sheet left on the upstream side in the conveyance direction (the printing unit 4 side) with respect to the cutting position does not leave the sheet tip (cutting position) in the decurling unit 2. Then, the sheet is fed back to the sheet supply unit 1, and the sheet is wound on the roll R1 or R2. By this feed back (back feed), collision with a sheet supplied again in the following back surface printing sequence is avoided.

  After the above-described front surface print sequence, the back surface print sequence is switched. The winding rotary body of the reversing unit 9 rotates in the opposite direction (clockwise direction in the drawing) to that during winding. The end of the wound sheet (the trailing edge of the sheet at the time of winding becomes the leading edge of the sheet at the time of feeding) is fed into the decurling unit 2 along the path of the broken line in the figure. In the decurling unit 2, the curl imparted by the winding rotary member is corrected. That is, the decurling unit 2 is provided between the sheet supply unit 1 and the printing unit 4 in the first path and between the reversing unit 9 and the printing unit 4 in the second path, and functions as a decal in any path. It is a common unit. The sheet whose front and back sides are reversed is sent to the printing unit 4 through the skew correction unit 3 and printed on the back side of the sheet. The printed sheet passes through the inspection unit 5 and is cut into predetermined unit lengths set in advance in the cutter unit 6. Since the cut sheet is printed on both sides, recording by the information recording unit 7 is not performed. Cut sheets are conveyed one by one to the drying unit 8, and sequentially discharged and stacked on the discharge unit 12 of the sorter unit 11 via the discharge conveyance unit 10. As described above, in duplex printing, a sheet passes through the first path, the second path, the first path, and the third path in this order.

  FIG. 3 is a flowchart showing the entire sequence of the printing operation controlled by the control unit. Based on the print command, in step S101, an initial print command table is created on the memory. The print command table is for printing unit images and maintenance patterns sequentially in a predetermined order. Details of the print command table will be described later.

  In step S102, unit images and maintenance patterns are sequentially printed on a continuous sheet in a predetermined order according to the created print command table. In step S103, it is determined whether printing of the print command table has been completed (Yes) or not (No). If the determination is Yes, the sequence is terminated. When judgment is No, it transfers to step S104. In step S104, it is determined whether the splice portion of the continuous sheet is detected by the splice sensor 17 during printing (Yes) or not (No). If the determination is yes, the process proceeds to step S105, and if the determination is no, the process returns to step S103 and is repeated. In step S105, the print command table is corrected according to the detection position (detection timing) of the splice unit. For correction, a pattern group insertion table composed of a print prohibited area (blank) and maintenance patterns before and after the print prohibited area is used. And it returns to step S103 and repeats a process. Details of the procedure for correcting the print command table will be described later.

  Since the splice is thicker than the original sheet, there is a possibility that a gap close to the splice will come into contact with the print head. Therefore, during the printing operation, when the splice part passes the position facing the print head, the print head 14 is temporarily retracted in the direction away from the sheet surface to widen the gap, and the splice part contacts the nozzle of the print head. You are avoiding that. After the splice passes, it returns to the gap suitable for the original print.

  In step S104, when the splice portion of the supplied continuous sheet S passes the detection position (directly below the splice sensor 17), the signal level of the splice sensor 17 changes and it is detected that the splice portion has passed. The splice sensor 17 is a reflection type photosensor, and captures the difference in surface reflectance between the sheet and the splice part (tape) or the step edge of the tape in the splice part from the change in the received light quantity of the reflected light. The splice sensor 17 may be a transmissive photosensor, and the splice portion can be detected by capturing the difference in transmittance between the sheet and the splice portion. The splice sensor 17 may be a contact sensor instead of an optical sensor. The contact-type sensor can detect the splice portion by detecting the change in the thickness of the splice portion by the change in the moving amount of the contact that contacts the sheet S.

  FIG. 4 illustrates an arrangement order in which unit images and maintenance patterns are sequentially printed on a continuous sheet in a predetermined order according to the print command table. FIG. 4A shows the arrangement order of the initial print command table created in step S101. FIG. 4B shows the arrangement order of the print command table corrected in step S105. In FIG. 4B, a splice portion 20 appears in the middle. In the figure, the type of pattern includes a blank, a maintenance pattern (non-discharge monitoring pattern, preliminary discharge pattern, etc.), and a cut mark (blank area) in addition to the unit image. In the example of FIG. 4, the margin a, maintenance pattern b, margin a, undischarge monitoring pattern c, preliminary discharge pattern d, cut mark e, preliminary discharge pattern d, unit image x1, cut mark f, unit from the leading edge of the sheet. Image x2,..., Unit image x13. Basically, a maintenance pattern is formed at a predetermined frequency. The predetermined frequency may vary depending on the size (number of print lines) of the unit image in the conveyance direction. In this example, as shown in FIG. 4A, a preliminary discharge operation is performed every time a set of four unit images or three unit images and one discharge failure monitoring pattern is printed according to the initial print command table. A preliminary discharge pattern is repeatedly formed. A symbol A in FIG. 4B is a predetermined pattern row inserted by correction, and the splice portion 20 is located near the center thereof.

  FIG. 5 is a diagram for explaining a procedure for correcting the initial print command table. As for the data, for each item, the table number, the type of pattern, and the numerical value of the number of print lines (corresponding to the length in the transport direction) are stored in the memory in a table format. The process of inserting the insertion table A (inserting an additional instruction group) into the place corresponding to the detection position (detection timing) of the splice unit 20 is illustrated. In this example, an insertion table consisting of table numbers 20 ′ to 24 ′ is inserted between the table number 19 and the table number 20 of the initial print command table. The table number 20 ′ is an undischarge monitoring pattern, the table number 21 ′ is a preliminary discharge pattern, the table number 22 ′ is blank, the table number 23 ′ is an undischarge monitoring pattern, and the table number 24 ′ is a preliminary discharge pattern. Table numbers 20 ′ and 21 ′ are maintenance patterns on the downstream side of the print prohibited area including the splice unit 20 (blank of the table number 22 ′). Table numbers 23 ′ to 26 ′ are maintenance patterns (including cut marks) on the upstream side of the print prohibited area including the splice unit 20 (blank of the table number 22 ′). That is, the print head is maintained before and after the print prohibition area.

  FIG. 6 is a flowchart showing a processing procedure for correcting the print command table in step S105. In step S201, based on detection of the splice unit 20, it is determined in which position on the print command table the insertion table is to be inserted. Calculation is made from the position (timing) at which the splice sensor 17 detects the splice unit 20 and the number of print lines on the print command table, and the position to insert data is determined. In step S202, it is confirmed with reference to the print command table whether the final pattern before insertion is an undischarge monitoring pattern (Yes) or not (No). If the determination is yes, the process proceeds to step S204, and if the determination is no, the process proceeds to step S203. In step S203, a discharge failure monitoring pattern (table number 20 ′ in FIG. 5) is set at the beginning of the insertion table. In step S204, it is determined from the print pattern before insertion whether the preliminary ejection operation of the print head is necessary (Yes) or not (No). The preliminary ejection operation is necessary for every predetermined time period (conveyance distance) for print head maintenance. When the preliminary ejection operation timing comes in a print prohibited area described later, it is necessary to perform preliminary ejection ahead of schedule. Judge. If the determination is yes, the process proceeds to step S205, and if the determination is no, the process proceeds to step S206. In step S205, a preliminary discharge pattern (table number 21 ′ in FIG. 5) is set in the insertion table.

  In step S206, a blank pattern (table number 22 ′ in FIG. 5) is set in a predetermined area including the splice unit 20 at the center. This blank pattern means a print prohibited area where printing is prohibited. In step S207, whether or not the first pattern after blanking is an undischarge monitoring pattern (Yes) or not (No) is checked with reference to the print command table. If the determination is Yes, the process proceeds to step S208. If the determination is No, the process proceeds to step S209. In step S208, the discharge failure monitoring pattern (table number 23 'in FIG. 5) is set next to the blank in the insertion table. In step S209, it is determined whether the preliminary ejection operation is necessary after the blank (Yes) or not (No). If the determination is Yes, the process proceeds to step S210. If the determination is No, the sequence is terminated. In step S210, a preliminary discharge pattern and a cut mark (table numbers 24 'to 26' in FIG. 5) are set at the end of the insertion table.

  When the insertion table is created, the control unit executes the insertion table (table numbers 20 ′ to 26 ′) next to the table number 19 and then returns to the table number 20 and performs control to continue printing. As described above, when the splice part is detected by the splice sensor 17, the print prohibition area including the splice part is set as blank, and the print command table is corrected so that the maintenance pattern is printed following the print prohibition area. Then, the predetermined order is changed. Then, printing is continued while avoiding the print prohibited area. Even if an undischarge nozzle occurs due to ink drying or the like during the period when the print prohibition area passes under the print head, maintenance of the print head immediately after that prevents the subsequent image from becoming defective. be able to. Further, when a maintenance pattern is originally required in the print prohibited area, the maintenance is performed before the print prohibited area, so that the state of the print head can be maintained well.

Even if the insertion table is inserted and interrupt processing is performed, the arrangement order of the unit images is not changed. There are cases where the order of images to be printed (page order) is significant, such as in a photo album. In such a case, if the order of images to be printed is changed, the user sees the print result. It must be rearranged. According to the present embodiment, such a situation can be avoided.
Next, a modification of the above embodiment will be described. In the above example, when the splice portion is detected, the insertion table is inserted, and the printing is continued without changing the subsequent arrangement order. On the other hand, in this example, when the splice portion is detected, the same insertion table is inserted, and thereafter, the printing order is changed so that the insertion position of the maintenance pattern becomes more appropriate.

  FIG. 7 illustrates the order in which unit images and maintenance patterns are sequentially printed in a predetermined order on a continuous sheet according to the print command table, as in FIG. FIG. 8 is a diagram for explaining the procedure for correcting the initial print command table, as in FIG. 5. The reference numerals in the figure are the same as those in FIG. In this example, the order of data after the table number 19 is changed with respect to the initial print command table, and the data after the table number 20 is replaced with new data. This operation is called rescheduling.

  In the example of FIG. 4, the arrangement of data after the corrected insertion data A is exactly the same as the arrangement of data before correction, and the position where the maintenance pattern is inserted into the arrangement of unit images is before and after the correction. It has not changed. For this reason, as shown in FIG. 4B, immediately after maintenance is performed using the insertion table, maintenance (monitoring pattern and preliminary ejection pattern immediately after the unit image 7) may be performed again. In contrast, in the example of FIG. 7, rescheduling is performed as shown in FIG. 7B, and after insertion data A, preliminary discharge is performed after printing four unit images. Therefore, there is no case where excessive maintenance is performed as shown in FIG. Since the possibility of excessive maintenance is reduced in printing following the splice unit 20, it is possible to reduce the waste of continuous sheets and further improve the total print throughput.

  FIG. 9 is a flowchart showing a processing procedure of a modified example of the correction of the print command table in step S105. In step S301, based on the detection of the splice unit 20, it is determined in which position on the print command table the insertion table is to be inserted. Calculation is made from the position (timing) at which the splice sensor 17 detects the splice unit 20 and the number of print lines on the print command table, and the position to insert data is determined. In step S302, whether or not the final pattern before insertion is a discharge failure monitoring pattern (Yes) is checked with reference to the print command table. If the determination is yes, the process proceeds to step S304, and if the determination is no, the process proceeds to step S303. In step S303, a discharge failure monitoring pattern (table number 20 in FIG. 8) is set at the beginning of the insertion table. In step S304, it is determined whether or not a preliminary ejection operation is necessary (Yes) from the print pattern before insertion (No). If the determination is yes, the process proceeds to step S305, and if the determination is no, the process proceeds to step S306. In step S305, a preliminary discharge pattern (table number 21 in FIG. 5) is set in the insertion table. In step S306, a blank pattern (table number 22 in FIG. 8) is set in a predetermined area including the splice unit 20 at the center. This blank pattern means a print prohibited area where printing is prohibited. In step S307, a maintenance pattern and cut marks (table numbers 23 to 26 in FIG. 8) are set next to the blank in the insertion table.

  From here on, the processing procedure is different from the example of FIG. In step S308, rescheduling is performed based on the number of unit images to be printed after the splice unit 20. Optimize maintenance pattern insertion locations for unit image alignment. Since the maintenance pattern is printed following the print prohibition area, further maintenance is unnecessary for a while. A maintenance pattern is formed at a predetermined frequency with the end of the insertion table (maintenance pattern behind the print prohibited area: table number 26) as a base point. The predetermined frequency may vary depending on the size (number of print lines) of the unit image in the conveyance direction. In this example, each time a set of four unit images or three unit images + one discharge failure monitoring pattern is printed, the insertion position of the maintenance pattern is reset so that the preliminary discharge operation is performed.

  According to each of the embodiments described above, printing on the splice is avoided, and a maintenance pattern is formed in an area following the splice to maintain the print head. Image printing can be performed satisfactorily. In rescheduling, the order of unit images is not changed, only the maintenance timing changes. Therefore, even when there is a meaning in the order of images to be continuously printed (page order), the user is not burdened with rearrangement.

  The above is an example in which the spliced portion of the continuous sheet is set as a print prohibited area because it is an inappropriate area that is not suitable for image printing. In addition to this, there may be unsuitable areas that are not suitable for image printing on a continuous sheet. Examples of improper areas include scratches, creases, tears, large debris, and dirt (aqueous, oily) that are not acceptable for image prints that are partially applied on a continuous sheet during sheet manufacture. In the present specification, these are collectively referred to as “dirt on a continuous sheet”. As another example of the unsuitable region, there is a marking portion such as a symbol or a mark intentionally marked in advance on the continuous sheet. If an image is printed on these unsuitable areas, the print quality is remarkably deteriorated, resulting in a defective product. Therefore, the detection unit detects these unsuitable areas, sets the print prohibition area in the same manner as described above, and controls to change the print order so that the maintenance pattern is printed following the print prohibition area. May be. Since the unsuitable region can be optically identified, the above-described splice sensor can be used as the detection unit.

DESCRIPTION OF SYMBOLS 1 Sheet supply part 4 Print part 13 Control part 14 Print head 17 Splice sensor

Claims (10)

A printing apparatus that sequentially prints a plurality of images by ejecting ink from a print head to a continuous sheet,
Means for identifying unsuitable areas that are not suitable for printing present in the continuous sheet;
When the inappropriate area is identified, the print head is not printed on the print prohibited area including the inappropriate area, and then maintenance of the print head is performed before resuming image printing after the print prohibited area. Means for controlling the continuous sheet to eject ink from the print head for
A printing apparatus comprising:   When the inappropriate area is identified, the controlling means controls the continuous sheet to eject ink from the print head for maintenance of the print head at least before and after the print prohibition area. The printing apparatus according to claim 1, wherein: Means for reversing the front and back of the continuous sheet printed by the print head;
The controlling means causes the print head to sequentially print a plurality of images on the first surface of the continuous sheet, inverts the front and back of the continuous sheet printed on the first surface, and again uses the print head to perform the first surface. The printing apparatus according to claim 1, wherein a plurality of images are sequentially printed on the second surface on the back side of the printer, and a continuous sheet is cut and discharged for each image.   The improper area is a splice portion of a continuous sheet, and when the splice portion passes through a position where the improper area faces the print head, the print head is temporarily retracted in a direction away from the continuous sheet. The printing apparatus according to claim 1, wherein the printing apparatus is characterized.   5. The apparatus according to claim 1, wherein the inappropriate region is at least one of a splice portion of a continuous sheet, a dirty portion on the continuous sheet, and a marking portion pre-marked on the continuous sheet. The printing apparatus according to item. A control method for a printing apparatus that sequentially prints a plurality of images by discharging ink from a print head to a continuous sheet,
If there is an unsuitable area that is not suitable for printing on the continuous sheet, do not print an image on the print prohibited area including the unsuitable area,
Discharging ink from the print head to the continuous sheet for maintenance of the print head before resuming printing of the image behind the print prohibited area;
A control method of a printing apparatus.   The control is performed so that ink is ejected from the print head to the continuous sheet for maintenance of the print head in at least one of before and after the print prohibition area if the inappropriate area exists. 6. The control method according to 6.   A plurality of images are sequentially printed on the first surface of the continuous sheet by the print head, the front and back sides of the continuous sheet printed on the first surface are reversed, and the second on the back side of the first surface is again printed by the print head. The control method according to claim 6 or 7, wherein a plurality of images are sequentially printed on the surface, and a continuous sheet is cut and discharged for each image.   The inadequate area is a splice portion of a continuous sheet, and when the splice portion passes a position facing the print head, the print head is controlled to be temporarily retracted in a direction away from the continuous sheet. The control method according to any one of claims 6 to 8, wherein the control method is characterized. The non-suitable region is at least one of a splice portion of a continuous sheet, a dirty portion on the continuous sheet, and a marking portion pre-marked on the continuous sheet. The control method according to item.

Images