JP2011177943A - Print control method and print apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cut a sheet at a correct position when printing is performed by using the continuous sheet and the sheet is cut. <P>SOLUTION: A cut mark is recorded in an area between one image and the next image to be printed. The recorded cut mark is detected. When the cut mark cannot be detected, a position of the cut mark which cannot be detected is estimated on the basis of information on an already-detected cut mark and information on a length of the image printed after the cut mark. A first cut position and a second cut position on the sheet for cutting off the blank area are set on the basis of the estimation. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a printing apparatus and method using continuous sheets.

  Patent Document 1 discloses a printing apparatus that performs double-sided printing on the front and back of a sheet by an inkjet method using a long continuous sheet wound in a roll shape. In this apparatus, the front end portion of the sheet supplied from the sheet supply unit is imaged, the print positions of a plurality of subsequent images are set based on this position information, and the sheet is cut with a cutter for each image after printing.

JP 2008-126530 A

  When repeatedly printing unit images of the same size on successive sheets, it is necessary to repeat sheet cutting at an accurate position so that the lengths do not become uneven when the cut sheets of the finished product are bundled. In Patent Document 1, the sheet is cut at a timing when the sheet will be conveyed after printing and come to the cutting position of the cutter with reference to the end of the printed image. Therefore, an error in the amount of sheet feeding between the image printing position and the cutter becomes an error in the final cut sheet conveyance direction size. In Patent Document 1, the conveyance error is made as small as possible by feedback measurement of the encoder of the conveyance means. However, if the sheet fluctuates or forms a loop in the sheet conveyance path between the image printing position and the cutter to form a loop and the sheet length fluctuates, it cannot be handled. Cutting becomes difficult.

  If a cut mark is recorded between the images and the sheet is cut based on the detection of the cut mark, the above problem can be solved. However, if the cut mark cannot be detected for some reason, it becomes difficult to cut the sheet at an accurate position.

  The present invention has been made based on recognition of the above-described problems. An object of the present invention is to provide a print control method and a printing apparatus capable of cutting a sheet at a more accurate position than before when performing printing using continuous sheets and cutting the sheets.

  The present invention is a method of printing using a continuous sheet, and sequentially printing a plurality of images on the sheet; recording a cut mark in a margin area between the one image to be printed and the next image; The recorded cut mark is detected; when the cut mark is detected, a first cutting position and a second cutting position for cutting off the blank area are set based on the detection; the cut mark is undetectable If there is, the cut mark position that could not be detected is estimated based on the information of the already detected cut mark and the length information of the image printed after the cut mark. A first cutting position and a second cutting position for cutting off the blank area are set; the first cutting position and the second cutting position are cut to cut the blank area; It is characterized by dropping.

  According to the present invention, the cut position of the sheet is set by recording and detecting the cut mark, and the cut position of the sheet is set by estimation even when the cut mark cannot be detected. Can prevent cutting defects.

Schematic showing the internal configuration of the printing device Block diagram of control unit Diagram for explaining the operation in single-sided print mode and double-sided print mode The figure which shows the arrangement of the plural images which are printed sequentially on the sheet The figure which shows the state which detects the cut mark Diagram for explaining operation when cut mark is detected The figure for explaining the operation when the cut mark is not detected The figure which shows the example which provided two cut mark sensors Flow chart showing specific operation sequence

  Hereinafter, an embodiment of a printing apparatus using an inkjet method will be described. The printing apparatus of this example uses a long and continuous sheet (a continuous sheet longer than the length of a repeated printing unit (referred to as one page or unit image) in the conveyance direction), and is used for both single-sided printing and double-sided printing. It is a compatible 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 such as printers, multifunction printers, copiers, facsimile machines, and various device manufacturing apparatuses. The printing process may be any system such as an inkjet system, an electrophotographic system, a thermal transfer system, a dot impact system, or a liquid development system. The present invention is not limited to print processing, but can be applied to a sheet processing apparatus that performs various processing (recording, processing, coating, irradiation, reading, inspection, etc.) on a roll sheet.

  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. 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 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.

  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 having a cutter 20 that cuts a printed sheet into a predetermined length. The cutter 20 includes two mechanical cutters 20a and 20b. As will be described later, the blank area between the images formed on the sheet is efficiently cut off by the upstream cutter 20a and the downstream 20b. The cutter unit 6 further includes a cut mark sensor 19 that optically detects a cut mark recorded on the sheet, and a plurality of conveying rollers for sending the sheet to the next process. A trash can 17 is provided in the vicinity of the cutter unit 6. The trash box 17 accommodates small sheet pieces whose margin areas are cut off by the cutters 20a and 20b and discharged as trash. The cutter unit 6 is provided with a sorting mechanism for discharging the cut sheet to the trash box 17 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. An edge sensor 21 for detecting 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. That is, the edge sensor 21 detects the edge of the sheet between the cutter unit 6 and the recording position by the information recording unit 7, and the information recording unit 7 controls the timing of information recording based on the detection timing of the edge sensor 21. The

  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. 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. In order to selectively guide the sheet conveyed on the first path to one of the second path and the third path, a path switching mechanism having a movable flapper is provided at a branch position of the path.

  The sorter unit 11 and the discharge unit 12 are 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 the discharge unit 12 including a plurality of trays. 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.

  A mark reader 18 is provided between the skew correction unit 3 and the printing unit 4. The mark reader 18 is a reflective optical sensor that optically reads the reference mark recorded on the first surface of the sheet conveyed from the reversing unit 9 from the side opposite to the printing side. The mark reader 18 has a light source (for example, a white LED) that illuminates the sheet surface and a light receiver such as a photodiode or an image sensor that detects light from the illuminated sheet surface for each RGB component. The mark can be read by changing the signal level of the light receiver or by analyzing the image data.

  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.

  FIG. 3A is a diagram for explaining the operation 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 feeding correction unit 3 is printed on the front surface (first surface) by 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. Here, a blank area is provided between one image and the next image, and a cut mark is recorded by the printing unit 4 in the blank area. The printed sheet passes through the inspection unit 5, and is cut into unit images by the cutter 20 based on the cut mark detection by the cut mark sensor 19 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. In summary, in the single-sided print mode, the following sequences (1) to (6) are executed under the control of the control unit 13.
(1) A sheet is sent out from the sheet supply unit 1 and supplied to the printing unit 4;
(2) Repeat printing of unit images and cut marks on the first surface of the supplied sheet by the printing unit 4;
(3) Repeat cutting of the sheet by the cutter unit 6 for each unit image printed on the first surface;
(4) The sheets cut for each unit image are passed through the drying unit 8 one by one;
(5) The sheets that have passed through the drying unit 8 one by one are discharged to the discharge unit 12 through the third path;
(6) The last unit image is cut and the sheet left on the print unit 4 side is sent back to the sheet supply unit 1.

  FIG. 3B is a diagram for explaining the operation in the duplex printing mode. In duplex printing, a back surface (second surface) print sequence is executed after a front surface (first surface) 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, the continuous sheet remaining on the upstream side in the conveying direction (on the printing unit 4 side) with respect to the cutting position is not supplied to the decurling unit 2 at the sheet leading end (cutting position). 1 and the sheet is wound on roll R1 or R2. By this rewinding, collision with the 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 with the front and back sides reversed is sent to the printing unit 4 through the skew correction unit 3 and a unit image and a cut mark are 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. In summary, the following sequences (1) to (11) are executed under the control of the control unit 13 in the duplex printing mode.
(1) A sheet is sent out from the sheet supply unit 1 and supplied to the printing unit 4;
(2) Repeat printing of unit images on the first side of the supplied sheet by the printing unit 4;
(3) Pass the sheet printed on the first surface through the drying unit 8;
(4) The sheet that has passed through the drying unit 8 is guided to the second path and wound on the winding rotary body of the reversing unit 9;
(5) After repeated printing on the first surface, the sheet is cut by the cutter unit 6 behind the last printed unit image;
(6) The sheet is wound around the winding rotary body until the end of the cut sheet passes through the drying unit 8 and reaches the winding rotary body. At the same time, the sheet cut and left on the print unit 4 side is sent back to the sheet supply unit 1;
(7) When the winding is completed, the winding rotating body is rotated in the reverse direction, and the sheet is supplied again to the printing unit 4 from the second path;
(8) Repeat printing of unit images and cut marks by the printing unit 4 on the second surface of the sheet supplied from the second path;
(9) Repeat cutting of the sheet by the cutter unit 6 for each unit image printed on the second surface;
(10) The sheets cut for each unit image are passed through the drying unit 8 one by one;
(11) The sheets that have passed through the drying unit 8 one by one are discharged to the discharge unit 12 through the third path.

  As described above, in backside printing in the single-sided printing mode and the double-sided printing mode, a cut mark is recorded together with the unit image print, and the sheet is cut by the cutter unit 6 based on the detection result of the cut mark. When the cut mark sensor 19 detects a cut mark, it may become undetectable due to various factors. Therefore, it is preferable to perform recovery print control when the cut mark becomes undetectable. The print control method will be described below.

  FIG. 4 shows some examples of the arrangement of a plurality of images (image 1, image 2, image 3,...) Sequentially printed on the sheet. In FIG. 4A, an image area 100 (100-1, 100-2, 100-3,...) And a blank area 101 (101-1, 101-2, 101-3, non-image area) are displayed. ...) are lined up alternately. Cut marks 102 (102-1, 102-2, 102-3,...) Are formed in each blank area 101.

  FIG. 4B shows an example of an arrangement in which the inspection pattern 103 for print head maintenance is added to the blank area 101 together with the cut mark 102. Each blank area 101 (101-1, 101-2, 101-3,...) Is an area where the cut mark 102 (102-1, 102-2, 102-3,...) Is formed. , The region where the inspection pattern 103 is formed is combined. In this example, the size of the unit image (image 1, image 2,...) In the transport direction is larger than that in FIG. FIG. 4C shows an example of an arrangement in which the inspection pattern 103 for print head maintenance is formed only in a part of the blank area. The size of the blank area in the transport direction is different between the blank area (101-1, 101-2) including the inspection pattern 103 and the blank area (103-3) not including the test pattern 103.

  FIG. 5 is a diagram showing a state in which a cut mark is detected by the cut mark sensor 19. The cut mark sensor 19 is a small optical sensor having a light source and a light receiving element. For example, the cut mark 102 is a 2 × 2 [mm] rectangular mark, and the spot diameter of the illumination light 110 illuminated on the cut mark 102 is φ1 [mm]. A small semiconductor light source (LED, OLED, semiconductor laser, etc.) is suitable for the light source. For example, the light source is a red LED, and the cut mark 102 is recorded with black ink having a good light absorption distribution characteristic with respect to red. In the sheet conveying direction, the blank area 101 has a width of a predetermined length M (4 mm). Further, in order to easily distinguish between the image area 100 and the cut mark 102, the length between the previous image area 100- (n-1) and the cut mark 102-n is half the length M ( 2 [mm]) blank (white region) is formed. However, it is not essential to provide such a blank. Thus, the cut mark is formed so as to be deviated downstream from the center of the blank area.

  The lower graph of FIG. 5 shows the change in the detection output of the light receiving element of the cut mark sensor 19. As the sheet moves, the blank area 101 passes the spot of the illumination light (detection position) of the sensor. At this time, as shown in the graph 120, the signal level of the detection output changes rapidly from high (white portion with high reflectance) to low (black portion with low reflectance). The degree of change (slope of the graph) is determined by the spot diameter of the illumination light 110. A position corresponding to a timing at which the changing signal level falls below a predetermined threshold value set in advance is detected as a mark position. Based on the detected mark position, sheet cutting positions by the cutter (cutting position 1 and cutting position 2 on the sheet) are set at two positions before and after the mark position. In the sheet conveyance direction, the interval between the cutting position 1 and the cutting position 2 is equal to or slightly larger than the length M of the blank area 101.

  The detection of the cut mark by the cut mark sensor 19 is not performed constantly during the printing operation, but only during a limited period in which it is estimated that the blank area of the sheet passes the detection position of the cut mark sensor 19. The estimation is performed by calculating from the image layout and the sheet conveyance distance. Accordingly, since the cut mark sensor does not read the print image, it is possible to prevent the print image from being mistaken as a cut mark.

  FIG. 6 is a diagram for explaining the operation when a cut mark can be detected by the cut mark sensor 19. When the cut mark 102 is correctly detected, the mark position is determined. A first cutting position (cutting position 1) and a second cutting position (cutting position 2) are set before and after (upstream and downstream) the mark position. The first cutting position is set upstream of the second cutting position with respect to the direction in which the sheet is conveyed during printing (state shown in FIG. 6 (1)).

  When the sheet is conveyed after the cut mark is detected, the first cutting position of the sheet first passes the cutting position of the first cutter 20a, and then the second cutting of the sheet passes the cutting position of the second cutter 20b. The distance is such that the position passes. The spot of the illumination light 110 is the detection position of the cut mark sensor 19. A distance C1 downstream from the detection position is a cutting position of the first cutter 20a, and a distance C2 (C2> C1) downstream from the detection position is a cutting position of the second cutter 20b. The distance relationship described above is that the distance between the cutting position 1 and the cutting position 2 (equal to or slightly larger than the length M of the blank area 101) is smaller than the difference between the distance C2 and the distance C1. Is realized. While conveying the sheet, the first cutting position is first cut by the first cutter 20a (the state shown in FIG. 6B). Next, the second cutting position is cut by the second cutter 20b (state shown in FIG. 6 (3)).

  Here, the meaning that the cutting at the first cutting position on the upstream side precedes the cutting at the second cutting position on the downstream side will be described. When the sheet is cut by the cutter 20, the sheet is temporarily stopped along with the sheet cutting operation, so that a slight force is transmitted to the upstream side of the sheet, and the mark reading operation in the inspection unit 5 and the printing operation in the printing unit 4 are performed. May have an effect. By first cutting at the first cutting position on the upstream side (first cutter 20a), the effect is only once. This is because, in the subsequent cutting at the second cutting position (second cutter 20b), the sheet to be cut is already separated from the upstream sheet and no force is transmitted. If the second cutting position is cut in advance, the above-mentioned influence occurs twice and the influence on inspection and printing becomes large. If a single cutter 20 is used and two continuous cuttings are performed with the same cutter, the upstream of the sheet is affected twice. Therefore, in order to precede the upstream side by cutting the sheet twice, it is necessary to provide two cutters.

  In the present embodiment, the operations of the first cutter 20a and the second cutter 20b are controlled based on the detection signal of the common cut mark sensor 19, but the first cutter 20a and the second cutter 20b A dedicated cut mark sensor may be provided for each. FIG. 8 shows an example in which two cut mark sensors 19a and 19b are provided. A cut mark sensor 19a is provided corresponding to the first cutter 20a, and a cut mark sensor 19b is provided corresponding to the second cutter 20b. Also in this case, when cutting off the blank area, the first cutting position is first set to the cutting order of the second cutting position first.

  FIG. 7 is a diagram for explaining the operation when the cut mark sensor 19 cannot detect a cut mark. If the cut mark cannot be detected, the position of the cut mark that could not be detected can be estimated based on the information on the cut mark that has already been detected and the information on the length of the image printed after the cut mark. it can. Based on this estimation, a first cutting position and a second cutting position for cutting off the blank area are set. Specifically, as shown in FIG. 7 (1), based on the previous cutting position 1, the distance M1 + L1 (M1: size of the image 1, L1: size of the margin portion) is away from the upstream side. The current cutting position 3 (first cutting position) is determined as the position. Further, as shown in FIG. 7 (2), based on the previous cutting position 2, the current cutting position 4 (second cutting) is located at a position away from the upstream by a distance L0 + M1 (L0: size of the margin). Position). While the sheet is being conveyed, the first cutting position is first cut by the first cutter 20a (the state shown in FIG. 7 (1)). Next, the second cutting position is cut by the second cutter 20b (state shown in FIG. 7 (2)). In this way, even if the cut mark cannot be detected due to various factors, it is possible to recover and continue the printing operation.

  FIG. 9 is a flowchart showing a specific operation sequence. In step S11, the printing operation is started. In backside printing in the single-sided printing mode or the double-sided printing mode, cut marks are sequentially printed together with unit images in an arrangement as shown in FIG.

  In step S12, the cut mark sensor 19 tries to detect a cut mark. As described above, the detection is performed during a limited period in which the blank area is estimated to pass the detection position of the cut mark sensor 19.

  In step S13, it is determined whether or not the cut mark has been correctly detected (YES) or not (NO). If the determination is YES, the process proceeds to step S14, and if the determination is NO, the process proceeds to step S16.

  In step S14, two cutting positions (first cutting position and second cutting position) for cutting off the blank portion are determined based on the detection result of the cut mark. Specifically, it is as described in FIG.

  In step S15, it is determined whether the image corresponding to the cut is the first image (YES) or not (NO) among the plurality of images to be printed in order. If the determination is YES, the process proceeds to step S16, and if the determination is NO, the process proceeds to step S17.

  In step S16, the cutting position is determined based on the information of the cue position before the sheet is conveyed to the printing unit. The first image is an image that is printed first at the leading edge of the continuous sheet, and there is no image that exists before it. After step S16, the process proceeds to step S19.

  In step S17, information on already detected cut marks is acquired. Specifically, information on mark detection in the previous or previous cut mark detection is acquired. The information here is a mark position, a first cutting position, and a second cutting position. As the cut mark that is as close as possible can be expected to improve the accuracy of estimation, first try to acquire the information of the previous cut mark detection, and if it is impossible to detect the previous time and information is missing, Acquires information on previously detected cut mark detection.

  In step S18, the cut mark position that could not be detected is calculated based on the information on the cut mark already detected in step S178 and the length information of the image printed after the cut mark. presume. Based on this estimation, two cutting positions (first cutting position and second cutting position) are determined. Specifically, it is as described in FIG. After step S18, the process proceeds to step S19.

  In step S19, the first cutting position determined as described above is conveyed to the cutting position of the first cutter 20a, and the sheet is cut by the first cutter 20a at that position. In step S20, the sheet is conveyed, the second cutting position is conveyed to the cutting position of the second cutter 20b, and the sheet is cut by the second cutter 20b at that position. Note that when the process of step S16 has been performed, the cutting position is only one of the first cutting positions, so step S20 is skipped. In step S <b> 21, the sheet pieces generated as dust are discharged into the trash box 17 by cutting at two places before and after the blank area.

  Step S22 is a loop that repeats until a plurality of images to be printed are all completed. If it is not the last image (determination is NO), the process returns to step S12 and the above-described processing is repeated. When the sheet cutting of the last image is completed (determination is YES), the sequence is completed.

  In the present embodiment, the cut mark is detected by the cut mark sensor 19 provided in the cutter unit 6. Since the cut mark sensor 19 detects the cut mark at a position close to the cut position, the sheet length varies due to a loop (swelling) or waviness occurring in the sheet along the sheet conveyance path between the image print position and the cutter. Even in this case, the sheet can be cut at an accurate position.

  Instead of the cut mark sensor 19, the inspection unit 5 may be used to detect a cut mark. Alternatively, the cut mark may be detected by using the cut mark sensor 19 and the inspection unit 5 together. In any form, the sensor for detecting the cut mark is provided downstream of the printing position and upstream of the cutting position by the cutter.

  Further, the present invention is not limited to a mode in which cut marks are recorded in all margin areas. A cut mark may be recorded once for a predetermined number (two or more) of blank areas. In this case, based on the detection of one cut mark, the cutting positions for several images until the next cut mark is detected are estimated, and the sheet is cut with a cutter.

By the way, the reason why the cut mark cannot be detected is as follows.
(1) When cut marks are not printed correctly:
For example, there is a case in which a cut mark causes a recording failure due to ink out of the print head 14 or temporary clogging of nozzles. In some cases, the cut mark may cause recording failure due to partial scratches or dirt on the sheet surface.
(2) In case of trouble with the sensor itself:
There are cases where the sensor is poorly detected due to electrical or optical noise or disconnection. In addition, there are cases in which detection failure occurs due to aging of the light source or light receiver.

  The above (1) and (2) can be distinguished by using the cut mark sensor 19 and the inspection unit 5 together. The cut mark in the blank area is first read and detected by the inspection unit 5, and then the same cut mark is detected by the cut mark sensor 19. If it is detected by both the inspection unit 5 and the cut mark sensor 19, it is in a normal state. On the contrary, if the cut mark cannot be detected in any of the cases, it is determined that the cut mark is not printed normally. If it can be detected by the inspection unit 5 but cannot be detected by the cut mark sensor 19, it is determined that the trouble is in the cut mark sensor 19. On the contrary, when the inspection unit 5 cannot detect but the cut mark sensor 19 can detect, it is determined that the inspection unit 5 is in trouble. In this way, the same cut mark is detected in time series by two sensors, and the cause of the cut mark being undetectable is determined based on the detection state of these two sensors.

  As described above, the cut position of the sheet is set by recording and detecting the cut mark, and the cut position of the sheet is set by estimation even when the cut mark cannot be detected. Can prevent cutting defects.

DESCRIPTION OF SYMBOLS 1 Sheet supply part 4 Print part 5 Inspection part 6 Cutter part 9 Inversion part 13 Control part 14 Print head 15 Operation part 19 Cut mark sensor

Claims (10)

A print control method for performing printing using continuous sheets,
Print multiple images sequentially on the sheet;
Record a cut mark in the margin area between one image to be printed in sequence and the next image;
Detecting the recorded cut mark;
If the cut mark is detected, a first cutting position and a second cutting position on the sheet for cutting off the blank area are set based on the detection result;
If the cut mark is undetectable, estimate the cut mark position that could not be detected based on the information of the already detected cut mark and the length information of the image printed after the cut mark, Setting a first cutting position and a second cutting position on the sheet for cutting off the margin area based on the estimation;
A print control method comprising cutting the margin area by cutting the first cutting position and the second cutting position. A method of performing double-sided printing using a continuous sheet,
Sequentially printing multiple images on the first side of the sheet;
Reversing a sheet printed with a plurality of images on the first side;
Sequentially printing a plurality of images respectively corresponding to the plurality of images printed on the first surface on the second surface on the back side of the first surface;
Recording a cut mark in a blank area between one image on the second side and the next image;
Detecting the recorded cut mark;
When the cut mark is detected, a first cutting position and a second cutting position for cutting off the blank area are set based on the detection result;
If the cut mark is undetectable, estimate the cut mark position that could not be detected based on the information of the already detected cut mark and the length information of the image printed after the cut mark, Setting a first cutting position and a second cutting position for cutting off the margin area based on the estimation;
Cutting a sheet printed on the second surface at the set cutting position;
A print control method.   The reversing of the front and back is performed by winding a sheet printed on the first surface in a printing unit onto a winding rotary member, and then feeding the sheet wound by reversely rotating the winding rotary member to the printing unit. The print control method according to claim 2, wherein printing is performed on the second surface.   4. The sheet according to claim 1, wherein the sheet is cut at the first cutting position first, and then the sheet is cut at the second cutting position downstream of the first cutting position. 5. The print control method described.   The sheet is cut at the first cutting position using a first cutter, and then the sheet is cut at the second cutting position using a second cutter provided downstream of the first cutter. The print control method according to claim 4.   The print control method according to claim 1, wherein the sheet pieces cut out by the cutting are discharged as trash into a trash box.   7. The cut mark according to claim 1, wherein the cut mark is formed to be deviated downstream from the center of the margin area, and a position corresponding to a timing at which a change in signal level falls below a threshold value is detected. A print control method according to claim 1.   2. The same cut mark is detected in time series by two sensors, and the cause of the detection of the cut mark is determined based on detection states of the two sensors. 8. The print control method according to any one of items 1 to 7. A sheet supply unit for holding and supplying continuous sheets;
A print section for printing on a sheet;
A sensor for detecting a cut mark recorded on the sheet;
A cutter unit for cutting the sheet;
A control unit,
The controller is
A plurality of images are sequentially printed by the print unit on the sheet supplied from the sheet supply unit;
Recording the cut mark in the print area in a margin area between one image to be printed sequentially and the next image;
Detecting the recorded cut mark with the sensor;
When the cut mark is detected, a first cutting position and a second cutting position for cutting off the blank area are set based on the detection result,
If the cut mark is undetectable, estimate the cut mark position that could not be detected based on the information of the already detected cut mark and the length information of the image printed after the cut mark, Setting a first cutting position and a second cutting position on the sheet for cutting off the margin area based on the estimation;
Cutting the printed sheet at the set cutting position with the cutter unit;
A printing apparatus characterized by controlling as described above. The cutter unit includes a first cutter for cutting the sheet at the first cutting position, and a second cutter for cutting the sheet at the second cutting position provided downstream from the first cutter,
The control unit controls to cut the sheet at the first cutting position using the first cutter and then cut the sheet at the second cutting position using the second cutter. The printing apparatus according to claim 9, wherein the printing apparatus is characterized.

Images