JP2014028438A - Printing method and sheet for printing used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the existence of a singular portion in a printing planned area after starting to print a long image, prevent ink and a sheet from being wasted, and print, even if the singular portion exists in the sheet, the image effectively using the sheet.SOLUTION: A printing method includes acquiring information about a distance to a singular portion existing in a continuous sheet to be used, which has previously been recorded with respect to the continuous sheet, and setting a printing schedule to form an image while avoiding the singular portion on the basis of the acquired information.

Description

  The present invention relates to a technique for printing a plurality of images on a continuous sheet.

  In a continuous sheet for printing, there may be a unique portion, which is an area that is unintentionally born in the sheet manufacturing process and is partially different in sheet characteristics. If an image is printed in an area where such a singular part exists, the image does not become a good quality product.

  In order to solve this problem, in Patent Document 1, the presence of a singular part is directly detected by a sensor, and the part where the singular part exists is not printed and conveyed to a singular part site by conveying the sheet for a predetermined length. A technique for avoiding printing is disclosed.

JP-A-61-64477

  In the technique disclosed in Patent Document 1, when printing a long image, if the image to be printed is longer than the length from the sensor that detects the singular part to the printing part that performs printing, unnecessary printing is performed. May not be avoided. In other words, the presence of the singular part of the planned print area may be detected after the printing of the long image is started. Then, since the printed part is discarded before detecting the singular part, the ink and the sheet are wasted. Even when an image that is not long is printed, when the sheet is conveyed at an extremely high speed, the singular part avoidance process may not be in time after the singular part is directly detected.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a printing method capable of effectively using a sheet even when printing is performed using a sheet having a unique portion.

  Therefore, in the present invention, a method for printing a plurality of images according to a schedule on a continuous sheet, which is pre-recorded on the continuous sheet to be used, obtains information on the distance to the singular part existing in the continuous sheet, Based on the acquired information, the schedule is set so as to print an image while avoiding the singular part.

  According to the above configuration, by performing printing based on the relative distance information of the singular part, the location where the singular part is present can be determined, and the sheet can be used effectively.

1 is a schematic cross-sectional view illustrating an internal configuration of a printing apparatus according to an embodiment. It is a block diagram which shows the concept of a control part. It is a schematic diagram which shows the example of a peculiar part and a peculiar part notice mark. 6 is a flowchart showing a flow of printing. It is a flowchart which shows the setting of a schedule from position information. It is a flowchart which shows the setting of a schedule from position information.

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

  Hereinafter, an embodiment of a printing apparatus using an inkjet method will be described. The printing apparatus of the embodiment uses a long and continuous printing sheet (a continuous sheet longer than the length of a repetitive print unit (one page or unit image) in the conveyance direction), and performs simplex printing and duplex printing. It is a high-speed line printer that supports both. 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 illustrating an internal configuration of a printing apparatus according to an embodiment. The printing apparatus according to the embodiment can perform double-sided printing on a first surface of a sheet and a second surface on the back side of the first surface using a 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.

  A singular part detection sensor 17 (detection unit) is provided between the skew correction unit 3 and the curl unit 2 and is a region in which the characteristics of the continuous sheet supplied from the sheet supply unit 1 are partially different. The singular part mark for identifying the singular part and the singular part notice mark are read. Details of the singular part 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. A sensor 21 that detects the leading edge of the cut sheet is provided on the upstream side of the information recording unit 7 and the downstream side of the cutter unit 6. Based on the detection timing of the sensor 21, the timing at which information is recorded by the information recording unit 7 is controlled.

  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 illustrating the concept of the control unit 13 according to the embodiment. 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 order.

  Next, the unique part existing in the continuous sheet will be described in detail. Singular parts are areas in which the characteristics of the continuous sheet are partially different, such as dirt, holes, scratches, sheet-to-sheet connection parts, breaks, tears, foreign matter contamination, discoloration, uneven thickness, impurities, etc. Refers to the area where there is.

  The singular part mark for identifying the singular part is a mark that is recorded within a predetermined range before and after allowing for an error with respect to the singular part on the sheet, and means that the singular part exists at the position. The singular part mark is recorded in advance when the sheet is manufactured, and is not recorded by the printing apparatus of the embodiment. The singular part mark only needs to be detectable by the singular part detection sensor 17, and is a simple rectangle, barcode, QR code (registered trademark), specific figure, character, or the like. The singular part mark is recorded as information indicating the position of the singular part.

  Information indicating the relative distance to the singular part position (single part notice mark) can be read by the singular part detection sensor 17 such as one recorded in the middle of the sheet, one recorded together at the head of the sheet, and the like. Anything is acceptable. Further, the information may be recorded together in a package in which sheets are packed instead of the continuous sheet itself, and may be input by the user to the host device. Furthermore, a form in which a recording medium such as a memory card on which information is collectively recorded is attached to the sheet and the user inputs to the host device may be used. Information is acquired by reading information input to the host device.

  FIG. 3 is a schematic diagram illustrating an example of a singular part and a singular part notice mark. For example, the singular part notice mark itself is not necessarily a singular part, and the singular part notice mark may be recorded with invisible ink or the like as shown in FIG. Further, as shown in FIG. 3B, both sides (outside the dotted line) of the sheet may be spare areas that are not originally included in the product. Also, even when the singular part notice mark is recorded using visible ink in the print range, the singular part notice mark 602 and the singular part notice mark 602 are arranged as shown in FIG. Unnecessary increase of the singular part due to the singular part mark can be avoided. In this case, since it can be considered that there is a mark 604 which also serves as a singular part notice mark and a singular part notice mark indicating information of the next singular part at one place in the transport direction, it is a dedicated mark rather than a figure combining them. Also good. The singular part notice mark has the relative distance to the next singular part position as information, but in other cases, such as when there are multiple singular part notice marks before the singular part mark, the next singular part notice mark The relative distance may be included as information. In addition, since the singular part position based on the singular part notice mark must also take into account the error of the transport distance, the accuracy is generally inferior to when detecting the singular part mark directly, but when that accuracy is sufficient, It is not always necessary to record the singular part mark on the sheet.

  Next, the print flow of the embodiment will be described. FIG. 4 is a flowchart illustrating a flow of printing using the printing apparatus according to the embodiment. First, sheet feeding is started from the roll R1 (step S301). Next, the singular part notice mark recorded at the leading edge of the fed sheet is read by the singular part detection sensor 17 (step S302), and the first singular part position information on the sheet is stored in the RAM 203 (step S303). Then, using the singular part position information stored in the RAM 203, various processes relating to printing are performed (step S304). Use of the singular part position information will be described later.

  Next, it is determined whether the singular part notice mark newer than the previous singular part notice mark is detected by the singular part detection sensor 17 during the printing performed so far (step S305). If not detected, the determination is NO and the process proceeds to S307. If detected, YES is determined and the process proceeds to S306.

  If it has been detected, the singular part position information of the next singular part is updated based on the information of the singular part notice mark detected up to the determination in step S305 (step S306). For example, as shown in FIGS. 3A and 3B, in the case of a singular part notice mark that does not affect the product, a plurality of singular part notice marks are recorded before the singular part. Therefore, the update in step S306 is performed a plurality of times, and the position of the singular part grasped by the recording apparatus gradually increases in accuracy. Or as shown in FIG.3 (c), when there exists a singular part notice mark in the same position as a singular part mark, it is updated to the position information of the following different singular part for every update.

  In step S301, it is determined whether continuous printing using the sheet that has started feeding is completed (step S307). If printing is not completed, NO is determined, and the process returns to step S304. It becomes YES and progresses to step S308. In step S308, the singular part notice mark to be read in step S301 when the sheet is fed next time is recorded in the position where it becomes the leading end of the sheet by the image forming apparatus itself, and the singular part recorded by the cutter unit 110 so that it can be rewound. Cut the tip side from the notice mark. Since the information to be included in the singular part notice mark to be recorded at this time is the relative distance to the next singular part notice mark, it is not the relative distance information contained in the last read singular part notice mark but based on the transport distance. The distance is newly calculated by subtracting to. Then, the sheet is rewound onto the roll R1 (step S309), and printing is completed.

  Here, an example is given in which the singular part notice mark in step S308 is recorded on the assumption that the singular part notice mark can be read at the head in step S302. However, if the singular part notice mark often appears on the sheet and there is no problem with the position of the next singular part until the first singular part notice mark that appears after feeding, there is no problem. The notice mark recording (step S308) may not be performed.

  Next, use of the singular part position information will be described. In the present invention, a print schedule is set using the singular part position information, and printing is performed according to the schedule.

  FIG. 5 is a flowchart illustrating a flow of setting the first schedule based on the singular part position information according to the embodiment. Here, the use of the singular part position information shown in step S304 of FIG. 4 is described in detail. Rather than first detecting the singular part mark directly, it is possible to apply all processes that can be executed by knowing in advance and with accuracy.

  FIG. 5A shows a flow in which a long image is printed without being applied to the singular part as a first example of use.

  First, it is determined whether or not the next image to be printed is a long image (step S401). Further, it is determined whether or not a singular part mark has already been detected (step S402).

  In this specification, the “long image” refers to an image that can detect a singular part mark that falls within the print range after the start of printing, such as longer than the length of the conveyance path from the singular part detection sensor 17 to the print head 14. Say. That is, there is a possibility that a long image may not be printed without printing where the singular part exists unless the singular part is specified by means other than the singular part mark.

  If the next image to be printed is not a long image, if there is a singular part, recording is performed while avoiding the singular part, and if there is no singular part, normal recording is performed (step S406). If a singular part mark has already been detected, the process of step S406 is similarly performed.

  On the other hand, if the next image to be printed is a long image and no singular part mark is detected, the long image can be printed without covering the area where the next singular part exists. It is determined whether or not it can be performed (step S403). This determination is based on the singular part position information recorded on the last detected singular part notice mark and the transport distance up to that point, so the next singular part position can be found. It is possible to determine whether printing can be performed without affecting the area to be printed.

  If printing can be performed without covering the area where the singular part is present, a long image is recorded (step S404). On the other hand, if a long image is printed as it is, if it is in an area where a singular part exists, printing of the long image is avoided (step S405).

  FIG. 5B shows a detailed print flow in step S405 of FIG.

  First, it is determined whether or not there is an image that can be printed before the next singular part position notified in advance among images scheduled to be printed other than the long image (step S411). If there is an image that can be printed, the image is printed (step S312), and a long image is printed immediately after the singular part mark (step S414). On the other hand, when there is no image that can be printed, the sheet is fed without printing anything up to the singular part mark (step S413), and a long image is printed immediately after the singular part mark (step S414). .

  In the example of the printing process shown in FIG. 5, the process for avoiding unnecessary printing that cannot be avoided in principle by direct detection of the singular part mark has been described. This processing can be applied even to an ultra-high-speed image forming apparatus that does not have time to avoid printing to an area where a singular part exists even after detecting a singular part mark even if it is not a long image. it can.

  Next, another use of the singular part position information shown in step S304 of FIG. 4 will be described in detail.

  FIG. 6 is a flowchart illustrating a flow of setting the second schedule based on the singular part position information according to the embodiment. Here, a method of limiting the timing for reading the singular part mark or the singular part notice mark by the singular part detection sensor based on the singular part position information from the singular part notice mark is shown.

  First, the relative distance between the singular part information sensor and the singular part position is updated based on the first singular part position information in the sheet stored in the RAM 203 described in step S303 in FIG. 4 (step S501). Then, it is determined whether the relative position is near 0 (step S502). If it is not near 0, NO is returned and the process returns to step S501. On the other hand, if it is near 0, the process proceeds to step S503. The reference to be regarded as near 0 may be appropriately determined depending on the accuracy of the relative distance and the range that can be detected by the singular part information sensor.

  If it is in the vicinity of 0, it is ensured that the singular part mark is included in the reading range (imaging range) of the singular part detection sensor, so the sheet is imaged (step S503). Then, the image captured in step S503 is analyzed (step S504). In the image analysis, the singular part position is specified from the position of the singular part mark detected as the analysis result in step S503, and the singular part position information with higher accuracy than the known singular part position information is acquired. Since the detection of the singular part mark here is equivalent to the detection in step S402, the subsequent processing proceeds to general processing step S406.

  The flow of use shown in FIG. 6 is an example in which the singular part mark is imaged using the singular part detection sensor. However, if the relative position information regarding the singular part notice mark is similarly available, the detection target is the singular part. The same applies to the notice mark. Further, although an example of imaging with an area sensor has been given, the same applies to a line sensor because the scan range can be limited. In this usage example, the singular part information sensor does not need to constantly monitor the sheet, and only needs to perform a detection action once or several times near the singular part position, and the analysis in step S504 takes time. It is particularly useful in construction. For example, it is possible to reduce the cost by replacing what has been continuously read by a line sensor and analyzed a huge amount of data with hardware having high processing performance with a simple one. Alternatively, in an ultra-high-speed image forming apparatus, it is also useful for insufficient charge or noise accumulated in the imaging device, which is a problem that occurs because the shutter interval of the line sensor becomes extremely short. That is, since it is sufficient to capture a limited number of times using an area sensor and a powerful flash, it is possible to detect the position of the singular part mark with high accuracy using an image with sufficiently high contrast.

  As described above, the present invention reads the singular part position information from the singular part notice mark recorded on the sheet, and records the singular part notice mark at the tip at the end of recording, thereby specifying the singular part position in advance and with high accuracy. , Image formation using it can be performed.

14 Print head 17 Singular part detection sensor 16 Host device

Claims (6)

A method of printing a plurality of images on a continuous sheet according to a schedule,
Acquired information on the distance to the singular part existing in the continuous sheet, which is recorded in advance with respect to the continuous sheet to be used,
A printing method characterized in that, based on the acquired information, the schedule is set so as to print an image while avoiding the singular part.   The printing method according to claim 1, wherein the information is recorded on the continuous sheet itself or previously recorded on a package of the continuous sheet.   The printing method according to claim 1, wherein the information is updated and recorded again when printing of the plurality of images is completed. The mark indicating the singular part formed in advance on the sheet is read by a sensor,
The printing method according to claim 1, wherein a reading range of the sensor is set in accordance with the acquired distance.   5. The printing method according to claim 1, wherein the schedule is changed according to whether or not an image can be printed before a singular part that appears next. 6. .   2. A continuous sheet used in the printing method according to claim 1, wherein the information is recorded in advance on the continuous sheet itself or a package of the continuous sheet.

Images