JP2014108622A - Printing device and printing device control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of an operation failure such as a sheet cutting error in a printing device.SOLUTION: A printing device comprises: a printing unit carrying out printing on a transported sheet; a sensor detecting a cut mark formed on the sheet; a cutting unit cutting the sheet on the basis of detection of the sensor; and measuring means for measuring a transport amount of the transported sheet. The sensor includes prediction means for detecting the cut mark within a range of an active period set based on measurement of the measuring means, and predicting an operation failure of the printing device in accordance with a change of a length of time since timing of starting the active period until detecting the cut mark.

Description

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

  When printing images on continuous sheets, a cut mark is printed between the images, the sheet is cut before and after the detected cut mark, and the cut mark is printed on the part where the image is printed. There is a printing apparatus that separates and removes the printed part from the printed part.

  In Patent Document 1, the cut marks on the sheet are sequentially monitored, and when the measured value of the distance between the cut marks is different from the calculated value, it is closest to the distance at which the next cut mark will appear based on the measured value. The sheet detected by the distance is recognized as a cut mark, and the sheet is cut.

JP 2004-338322 A

  However, for example, when a state in which a continuous sheet cannot be stably conveyed due to deterioration of the components constituting the printing apparatus due to use, the configuration of Patent Document 1 detects a cut mark or other mark as a detector. May not be properly detected. If it does so, it will become impossible to cut | disconnect a sheet | seat appropriately and it will become easy to generate | occur | produce a paper jam within an apparatus with the sheet | seat conveyed without being made | formed appropriately. Once a paper jam has occurred, recovery to process the paper jam in the device takes a significant amount of time.

  SUMMARY OF THE INVENTION Accordingly, the present invention provides a printing apparatus and a printing apparatus control method in which the occurrence of malfunctions (sheet cutting errors and paper jams resulting from this) based on state changes (such as deterioration with time) of the printing apparatus is suppressed. With the goal.

  In order to achieve the above object, a printing apparatus of the present invention cuts a sheet based on a print unit that prints on a conveyed sheet, a sensor that detects a cut mark formed on the sheet, and detection by the sensor. A printing apparatus comprising: a cutting unit; and a measuring unit that measures a conveyance amount of a conveyed sheet, wherein the sensor detects a cut mark within an active period set based on measurement by the measuring unit. And a predicting unit that predicts a malfunction of the printing apparatus in accordance with a change in the length of time from the start of the active period to the detection of the cut mark.

  According to the configuration of the present invention, the timing at which a malfunction that may cause a problem in use in the printing apparatus can be predicted from the relationship between the change in timing at which the cut mark is detected and the usage status of the printing apparatus. Based on the prediction, the user can end the print job and maintain the printing apparatus. As a result, it is possible to prevent the occurrence of a malfunction at a problematic level.

1 is a diagram illustrating a system configuration of a printing apparatus according to an embodiment. 1 is a schematic diagram illustrating an internal configuration of a printing apparatus according to an embodiment. FIG. 3 is a diagram for explaining an operation during single-sided printing of the printing apparatus illustrated in FIG. 2. It is a figure showing the example of the communication data format between the units of this embodiment. It is a figure showing the structure of the print head and undischarge detection sensor of this embodiment. It is a figure which shows the example of the arrangement | sequence of the some image printed sequentially on a sheet | seat. It is a figure explaining the state which has detected the cut mark with the cut mark sensor. It is a figure for demonstrating the operation | movement which detects a cut mark with a cut mark sensor and cut | disconnects a sheet | seat. It is a figure showing the detail of the image processing part of the system configuration | structure shown in FIG. It is a figure which shows the window signal and cut mark sense signal of this embodiment. It is a figure for demonstrating the relational expression between the use performance of an apparatus and the cut mark detection time, and prediction of the time until error generation.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

(Embodiment)
<Outline of printing device>
Hereinafter, an embodiment of a printing apparatus using an inkjet method will be described. The printing apparatus according to the present embodiment is a printing apparatus that uses a line type print head that uses a continuous sheet wound in a roll shape and can perform high-speed printing corresponding to both single-sided printing and double-sided printing. The printing apparatus of this embodiment is suitable for the field of printing a large number of sheets, for example, in a print laboratory.

  FIG. 2 is a schematic cross-sectional view of the internal configuration of the printing apparatus according to the present embodiment. The printing apparatus includes 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 sheet winding unit 9, and a discharge unit. Each unit includes a transport unit 10, a sorter unit 11, a discharge tray 12, and a control unit 13. The sheet is conveyed along a sheet conveyance path indicated by a solid line in the drawing by a conveyance mechanism including a roller pair and a belt, and is processed in each unit.

  The sheet supply unit 1 is a unit that stores a continuous sheet wound in a roll shape and supplies it from there. The sheet supply unit 1 can store two rolls R1 and R2 of continuous sheets, and has a configuration in which a sheet is selectively drawn out from the two rolls and supplied. The number of rolls of continuous sheets that can be stored is not limited to two, and one or three or more rolls may be stored.

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

  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 print unit 4 is a unit that forms an image by applying ink to a sheet to be conveyed by the print head 14. The printing unit 4 includes a plurality of conveyance rollers that convey the sheet, and a sensor (non-discharge detection sensor) that detects a cut mark printed on the sheet. The print head 14 is 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 assumed to be used. The print head 14 includes a plurality of print heads arranged in parallel along the sheet conveyance direction. In this example, the print head 14 is composed of four print heads 14K, 14C, 14M, and 14Y corresponding to inks of four colors K (black), C (cyan), M (magenta), and Y (yellow). ing. The number of ink colors and the number of print heads are not limited to four. 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. Details of the configuration such as the positional relationship between the print heads 14K, 14C, 14M, and 14Y and the discharge failure detection sensor will be described later with reference to FIG.

  The inspection unit 5 is a unit that optically reads the inspection pattern or image printed on the sheet by the printing unit 4 and inspects the nozzle state of the print head, the sheet conveyance state, the image position, and the like.

  The cutter unit 6 is a unit including a mechanical cutter that cuts a printed sheet into a predetermined length. The cutter unit 6 includes two mechanical cutters 18 and 19 and a plurality of conveying rollers for feeding the sheet to the next process. As will be described later, the margin area between the images formed on the sheet is efficiently cut off by the two of the first cutter 18 on the upstream side and the second cutter 19 on the downstream side. The cutter unit 6 further includes a cut mark sensor 17 that functions as a reading unit that optically detects a cut mark printed on the sheet, and a plurality of conveying rollers for sending the sheet to the next process. The optical sensor constituting the cut mark sensor 17 is sensitive to at least the color used for the cut mark. Details of the control of the cut portion will be described later with reference to FIGS.

  The information recording unit 7 is a unit that records print information such as a print serial number and date on the back side of the cut sheet.

  The drying unit 8 is a unit that heats the sheet printed by the printing unit 4 and dries the ink applied to the sheet in a short time. The drying unit 8 includes a conveyance belt and a conveyance roller for sending the sheet to the next process.

  The sheet winding unit 9 is a unit that temporarily winds a continuous sheet that has been printed on the surface of the sheet (front surface printing) when printing on both sides of the sheet (double-sided printing). The sheet winding unit 9 includes a rotating winding drum for winding the sheet. The continuous sheet that has been printed on the surface and has not been cut is temporarily wound on a winding drum. When the winding is completed, the winding drum rotates reversely, and the wound sheet is 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 the back side (back side printing).

  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 sorter unit 11 is a unit that sorts and discharges printed sheets to different trays 12 for each group as necessary.

  The control unit 13 is a unit that controls each unit of the entire printing apparatus. The controller 13 includes a CPU, a memory, a controller 15 having various I / O interfaces, and a power source. The operation of the printing apparatus is controlled based on an instruction from the controller 15 or an external device 16 such as a host computer connected to the controller 15 via an I / O interface.

<Basic operation during printing>
Next, a basic operation at the time of printing of the printing apparatus according to the present embodiment will be described. In the printing apparatus of this embodiment, as described above, printing on one side of a sheet (single-sided printing) and printing on both sides (double-sided printing) can be performed. Here, single-sided printing will be described as an example of operation.

  FIG. 3 is a diagram for explaining the operation during single-sided printing. A conveyance path from the time when the sheet supplied from the sheet supply unit 1 is printed and discharged to the discharge tray 12 is indicated by a bold line. The sheets supplied from the sheet supply unit 1 and processed by the decurling unit 2 and the skew feeding correction unit 3 are printed on the surface by the printing unit 4. The printed sheet passes through the inspection unit 5 and is cut by the cutter unit 6 for each predetermined unit length set in advance with the cut mark as a reference position. Print information of the cut sheet (cut sheet) is recorded on the back surface 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 tray 12 of the sorter unit 11 via the discharge conveyance unit 10.

<Control of the cut part>
Next, the control of the cut unit 6 will be described in detail.

  FIG. 6 shows an example of an arrangement of a plurality of images that are sequentially printed on a sheet. In FIG. 6, a plurality of images are shown as an image n (image 1, image 2, image 3,...) With a printing order n (n is an integer). On the sheet, an image area 100, which is an area on which the target image is printed, and a blank area 101, which is a non-image area, are arranged so as to be alternately arranged in the sheet conveyance direction. A cut mark 102 is formed in each margin area 101. In FIG. 6, the image area corresponding to the image n is indicated as an image area 100-n (n is an integer). Further, a blank area adjacent to the image area 100-n on the downstream side in the sheet conveyance direction during printing is shown as a blank area 101-n, and a blank area adjacent to the image area 100-n on the upstream side is a blank area 101-n. It is shown as (n + 1) (n is an integer). The cut mark printed in the blank area 101-n is shown as a cut mark 102-n, and the cut mark printed in the blank area 101- (n + 1) is shown as a cut mark 102- (n + 1) (n is integer).

  FIG. 7 is a diagram illustrating a state in which a cut mark on the sheet is detected by the cut mark sensor. The cut mark sensor 17 is a small optical sensor having a light source and a light receiving element. In this example, the cut mark 102 is a rectangular mark of 2 × 2 [mm], and the spot diameter of the illumination light 110 of the cut mark sensor 17 irradiated on the cut mark 102 is φ1 [mm]. A small semiconductor light source (LED, OLED, semiconductor laser, etc.) is suitable for the light source. In this example, it is assumed that the light source is a red LED, and the cut mark 102 is printed with black ink having a good light absorption distribution characteristic with respect to red. The blank area 101 has a predetermined length M (4 mm) in the sheet conveyance direction. In the print order, the image area 100- (n-1) is first printed. Next, the cut mark 102-n is printed in the blank area 101-n adjacent thereto. Between the image area 100 (n-1) and the cut mark 102-n, a blank area (white [mm]) that is half the length M of the blank area 101-n in the sheet conveyance direction (white [mm]). Part) is formed. This is to facilitate the distinction between the image area 100 and the cut mark 102. However, it is not essential to provide such a blank.

  The lower graph in FIG. 7 shows the change in the detection output of the light receiving element of the cut mark sensor 17. The horizontal axis of the graph indicates the position on the sheet in the sheet conveyance direction. In addition, the vertical axis of the graph indicates the signal value of the reflectance of the irradiated light detected by the light receiving element of the cut mark sensor 17 for each position as an output value.

  As the sheet moves, the blank area 101 passes through the spot (detection position) 110 of the illumination light of the cut mark sensor 17. At this time, the output level of the detected signal suddenly changes from “high” to “low” as shown in the graph 120 of FIG. That is, a portion (white portion) where no printing is performed in the blank region 101-n of the sheet reflects a large amount of light, so that the white portion is relatively high when passing the detection position of the cut mark sensor 17. Reflectance is detected. Further, the portion (black portion) where the cut mark 102-n is printed in the blank area 101-n absorbs more light and the reflection is reduced compared to the white portion, so the black portion is the detection position 110 of the cut mark sensor 17. When passing through, a relatively low reflectance is detected. From such behavior of the output level of the detected signal, the cut mark sensor 17 recognizes that the cut mark 102-n has been detected when detecting a relatively low reflectance.

  The detection of the cut mark 102-n by the cut mark sensor 17 is not constantly performed during the printing operation, but a detection period in which the margin area 101-n of the sheet is estimated to pass the detection position 110 of the cut mark sensor 17 is set. And do it. The cut mark sensor reads the cut mark only during this detection period. An estimated detection period is obtained by calculating based on the distance in the sheet conveyance direction from the print head 14 that prints the cut mark to the cut mark sensor 17, the layout of the target image, and the sheet conveyance speed. Can do. This prevents the cut mark sensor 17 from reading a target image originally printed for the purpose of printing, thereby preventing the target image from being mistaken as a cut mark.

  FIG. 8 is a diagram for explaining the operation of the cutter unit that detects the cut mark by the cut mark sensor and cuts the sheet.

  The cutter unit 6 includes a cut mark sensor 17, a first cutter 18, and a second cutter 19 in this order from the upstream side in the sheet conveyance direction. The position of the spot of the illumination light 110 of the cut mark sensor 17 becomes the cut mark detection position. This detection position is arranged to be separated upstream from the sheet cutting operation position of the first cutter 18 by a distance C1 in the sheet conveyance direction and further upstream from the sheet cutting operation position of the second cutter 19 by a distance C2. ing. The distance C1 and the distance C2 satisfy the relational expression C1 <C2.

  Here, the first state shown in FIG. 8 will be described. When the cut mark 102 on the sheet is detected by the cut mark sensor 17, the position of the detected cut mark is determined as a reference position for cutting the sheet. Before and after the reference position, a first cutting position and a second cutting position of the sheet are set. The first cutting position is set upstream of the second cutting position in the sheet conveyance direction. That is, the first cutting position is set corresponding to the upstream end of one blank area 101 in the sheet conveyance direction, and the second cutting position is set corresponding to the downstream end of the blank area 101. The In FIG. 8, the cutting position 1 corresponds to the first cutting position, and the cutting position 2 corresponds to the second cutting position. Similarly, the cutting position 3 corresponds to the first cutting position, and the cutting position 4 corresponds to the second cutting position.

  The corresponding interval between the first cutting position and the second cutting position can be set to a length equal to the length M of one blank area 101 in the sheet conveyance direction. Further, this interval may be set to a length larger than the length M. The distance relationship between the corresponding first cutting position and second cutting position is set as follows. When the sheet is conveyed after the cut mark is detected, first, the first cutting position of the sheet passes through the sheet cutting operation position of the first cutter 18. Next, the second cutting position of the sheet passes through the sheet cutting operation position of the second cutter 19. Such a distance relationship can be realized by making the distance between the first cutting position and the second cutting position smaller than the difference between the distance C2 and the distance C1.

  The second state in FIG. 8 shows a state in which the conveyance of the sheet is continued after the cut mark is detected and the first cutting position of the sheet is cut by the first cutter 18.

  The third state in FIG. 8 shows a state in which the sheet is further conveyed from the second state and the second cutting position of the sheet is cut by the second cutter 19.

  By repeating the above-described operation of the cutting unit 6 as necessary, the portion of the sheet on which the image is printed can be obtained separately from the portion of the blank area.

<System configuration of printing device>
Next, the system configuration of the printing apparatus according to the present embodiment will be described with reference to FIG.

  FIG. 1 is a diagram illustrating a system configuration of a printing apparatus according to the present embodiment. Although an actual printing apparatus system has a complicated structure that cannot be drawn in this drawing, the internal configuration thereof will be described only along the relevant portions.

  First, the control unit is divided for each print head that performs printing. There is a control unit 140K for the print head 14K (black), a control unit 140C for the print head 14C (cyan), a control unit 140M for the print head 14M (magenta), and a control unit 140Y for the print head 14Y (yellow). .

  In addition to the control unit, there are three elements that should be added to facilitate understanding of the functions in the explanation of the data flow. One is a host computer (hereinafter also simply referred to as a host) 5020, the other is a print head 14K, 14C, 14M, 14Y, and the last one is an encoder 5040.

  The host 5020 exists outside the printing apparatus, and transfers print data to the printing apparatus, more strictly, to a reception interface (I / F) 507 that is a data reception unit of the control unit 140K.

  The print heads 14K, 14C, 14M, and 14Y are heads for creating a print output that is a product of the printing apparatus. Data for controlling the operation of the print heads 14K, 14C, 14M, and 14Y, that is, print data, ejection pulse signals, and the like are generated inside the control units 140K, 140C, 140M, and 140Y.

  The encoder 5040 is a sensor that is directly connected to, for example, a conveyance roller that conveys a sheet, detects the position by one rotation in synchronization with one rotation of the conveyance roller, and outputs position information. The position information signal output from the encoder can be used to calculate the sheet conveyance amount.

  Here, the inside of the control units 140K, 140C, 140M, and 140Y will be described. Since each control unit has the same configuration, the main block will be described using the control unit 140K as an example unless otherwise specified. The CPU 505 is a processing device that manages and manages operations. In the figure, an SD-RAM 506 shown as a general-purpose memory is a main memory of the printing apparatus system. Incidentally, this does not necessarily have to be an SD-RAM. Either a D-RAM, an S-RAM, or a memory other than the SD-RAM may be used as long as the memory belongs to the definition of RAM.

  Next, the random logic part will be described. A reception interface (I / F) 507 receives data transferred from the host 5020. For example, the reception interface 507 captures a signal in accordance with an interface protocol such as USB or PCI Express, and generates data from the captured signal in a form that can be easily handled by the control unit 140K. The generated data is stored in the SD-RAM 506. At this time, the data is often shaped into a 1-byte unit. The part in the SD-RAM 506 controlled by the reception interface 507 is usually called a reception buffer 508.

  Data stored in the reception buffer 508 in the SD-RAM 506 is read into the image processing unit 509, and image processing such as conversion from a luminance signal (RGB) to a density signal (CMYK), gamma conversion, and error diffusion is performed. . Data after image processing is stored in the print buffer 510.

  In this embodiment, as described above, a control unit is provided for each print head, and the print head is provided for each ink color. Therefore, in one control unit, conversion from the luminance signal (RGB) to the density signal of the print head is performed for a single color. For example, the control unit 140K performs signal conversion only for black (K), and subsequently performs image processing such as scaling, gamma conversion, and error diffusion in the same single control unit. Details of the image processing performed by the image processing unit 509 will be described later with reference to FIG.

  By performing the processing up to the storage in the print buffer 510 with multi-valued data (mainly compressed for each color), the necessary capacity of the reception buffer 508 and the print buffer 510 can be reduced. Thereby, it is possible to reduce the cost increase due to the increase in the size of the SD-RAM 506 due to the increase in the number of nozzles and the number of colors in the print head.

  Data stored in the print buffer 510 is read into the data development unit 511 in accordance with the timing of each print control, and various processes such as multi-value data development and mask control are performed. Print data obtained by these processes is sent to the head drive unit 512. The head drive unit 512 transfers print data to the print head 14K, or transmits an ejection pulse signal to the print head 14K based on the print data. In this way, hardware control specific to the print head 14K is performed.

  The print timing generation unit 513 receives signals from the encoder 5040, generates and transmits various print timing signals at appropriate intervals, and the data development unit 511 and the head drive unit 512 operate in real time at appropriate timings. to enable.

  The transmission interface (I / F) 514 receives an appropriate print timing signal for the print head 14 </ b> C to be printed next to the print head 14 </ b> K from the print timing generation unit 513. The transmission interface (I / F) 514 reads the luminance signal (RGB) from the reception buffer 508 according to the print timing signal, and transmits the data to the control unit 140C.

  The control unit 140C receives the data transmitted from the transmission interface 514 of the control unit 140K by the reception interface, performs the same processing as the control unit 140K based on the received data, and performs hardware control on the print head 14C. Thereafter, according to the same processing, the control unit 140M performs hardware control on the print head 14M, and the control unit 140Y performs hardware control on the print head 14Y to print an image.

  FIG. 5 is a schematic diagram illustrating the positional relationship between the print head and the undischarge detection sensor in the print unit 4 of FIG. The print heads 14K (black), 14C (cyan), 14M (magenta), and 14Y (yellow) provided for each ink color in this embodiment are arranged in this order from the upstream side in the sheet conveyance direction. As described above, each print head is formed with an inkjet nozzle row in a range that covers the maximum width of the sheet that is expected to be used. In this example, in one print head, short nozzle rows in which a plurality of nozzles are arranged are arranged in a staggered manner so as to cover the maximum width of the sheet as a whole. However, in the present invention, the configuration of the print head is not limited to this configuration. For example, the print head may include a single nozzle row having a length that covers the maximum width of the sheet. Printing is performed by applying ink in accordance with print data from each print head to a sheet (recording paper) 605 conveyed in a direction orthogonal to the nozzle arrangement direction. The undischarge detection sensor 515 is attached downstream of the print head 14K and upstream of other print heads in the sheet conveyance direction, and indicates whether or not the cut mark to be printed on the sheet has been correctly printed by the print head 14K. To detect. The undischarge detection sensor 515 is a small optical sensor having a light source and a light receiving element, like the cut mark sensor 17 of the cutter unit 6 in FIG. The detection of the cut mark by the undischarge detection sensor 515 is not performed continuously during the printing operation, but is performed by setting a period during which the blank area of the sheet is estimated to pass the detection position of the undischarge detection sensor 515 as a detection period. . The undischarge detection sensor 515 reads the cut mark only during this detection period. The estimated period can be obtained by calculating based on the sheet conveyance distance from the print head for printing the cut mark to the cut mark sensor, the layout of the target image, and the sheet conveyance speed. By setting the detection period in this way, the discharge failure detection sensor 515 does not read the target image originally intended for printing, and thus it is possible to prevent the target image from being mistaken as a cut mark.

  The cut mark print control will be described with reference to FIG. The undischarge detection sensor 515 detects a cut mark printed on the sheet by the print head 14K controlled by the control unit 140K. If the cut mark cannot be detected in the detection period in which the blank area 101 of the sheet is estimated to pass through the discharge failure detection sensor 515, the discharge failure detection sensor 515 notifies the transmission interface unit 514 that the cut mark has not been printed. . The transmission interface unit 514 that has received the notification that the cut mark is not detected transmits information indicating that the cut mark has not been printed to the control unit 140C together with the image data to be transmitted.

  FIG. 4 shows an example of the format of data that the transmission interface unit 514 transmits to the control unit 140C. For example, an area for notifying that a cut mark has not been printed as part of header data for image data may be provided, and information may be added to this part. Usually, as shown in the column (a), the discharge failure detection flag is set to 0. Only when the cut mark is not printed, 1 is set in the undischarge detection flag as shown in the column (b). Thereby, it is possible to determine on the data whether or not the cut mark has been printed.

  That is, when the discharge failure detection flag is set to 0, the cut mark is printed by the control unit 140K that prints with black ink in the area where the cut mark is printed on the sheet. It shows that. In this case, printing is not performed by the control units 140C, 140M, and 140Y that perform printing with inks of different colors. On the other hand, when the undischarge detection flag is set to 1, this indicates that the cut mark could not be printed with the black ink, and another color is set by another control unit based on this information. Print the cut mark with the ink. For example, the cut mark can be printed using cyan ink by the control unit 140C. At this time, the ink used may be one color or multiple colors.

  FIG. 9 is a diagram showing details of the image processing unit 509 in the control unit 140C shown in FIG. An image processing unit 509 performs image processing such as conversion from a luminance signal to a density signal, gamma conversion, and error diffusion to generate image data. There are similar image processing units in the control units 140K, 140M, and 140Y, and the illustration is omitted here.

  The print data for printing the cut mark is one of the image data. When image data for cut mark printing is input to the image processing unit, a color conversion 3DLUT (three-dimensional lookup table) 1004 is used to perform color conversion from RGB to each ink color according to the input data. To do. For example, the image processing unit 509 in the control unit 140K performs color conversion from RGB to black, and the image processing unit in the control unit 140C performs color conversion from RGB to cyan.

  Although the image data is created so that the cut mark is generated in a single black color and the print control is performed, the undischarge detection flag may be set to 1. This is a case where printing cannot be performed correctly due to a change in state of the print head, the conveyance roller, or the like, or a defective state occurring in the print head, the conveyance roller, or the like. When the discharge failure detection flag is set to 1, data including the information is transmitted from the transmission interface 514 of the control unit 140K to the control unit 140C. The transmitted data is received by the reception interface of the control unit 140C and sent to the image processing unit via the reception buffer. Thereby, the undischarge detection flag 1002 is notified to the density conversion unit 1001 of the control unit 140C. The density conversion unit 1001 recognizes that 1 is set in the discharge failure detection flag 1002.

  Here, for example, similarly, as part of the header data for the image data, an area for notifying that the transmitted image data is a cut mark is provided, and when the transmitted image data is a cut mark, a cut image flag 1003 is provided. 1 may be set. When 1 is set in the cut image flag 1003, the density conversion unit 1001 recognizes this. The cut image flag and the undischarge detection flag indicate that the image data is a cut mark and that it has not been printed correctly.

  Based on the above recognition, the density conversion unit 1001 performs color conversion using an undischarge detection 3DLUT 1005 that is a three-dimensional lookup table different from the 3DLUT 1004 used for color conversion of normal image data. As a result of this color conversion, image data of a cut mark that is originally generated for black and should not be generated for another color is generated for cyan. The generated image data is stored in the print buffer, and then sent to the head driving unit through processing in the data developing unit, and based on this, printing by the print head 14C is performed. In this way, the cut mark can be printed with an ink different from black (in this example, cyan).

  Similarly, magenta image data is generated by the image processing unit of the control unit 140M, and image data for yellow cut mark printing is generated by the image processing unit of the control unit 140Y, and printing is performed by the print heads 14M and 14Y. Accordingly, a cut mark image using cyan, magenta, and yellow inks can be generated. The ratio of the data for each ink color can be arbitrarily set by setting the discharge failure detection 3DLUT. For example, the undischarge detection 3DLUT can be set so that the ratio of the data for each ink color is cyan: magenta: yellow = 1: 1: 1. In this case, the cut mark can be printed with a process black color having three colors of cyan, magenta, and yellow as process colors, and reading by the cut mark sensor 17 can be facilitated.

  If the discharge failure detection sensor 515 does not detect the cut mark, the state is notified to the CPU 505 and also to the host 5020. As a result, the printing of the image data on and after the next page is canceled, and the process proceeds to a print end process.

  FIG. 10 shows the details of the present invention that are being carried out to further ensure the stable operation of the device in such a system. In FIG. 10, two types of waveform signals are shown with the horizontal axis as time or sheet conveyance amount. A signal 1101 is a signal generated inside the apparatus in synchronization with sheet conveyance, and can schematically indicate a target image area and a cut mark area in the conveyed sheet. The signal 1101 is a window signal indicating a sheet conveyance amount calculated by counting a signal from an encoder unit that is directly connected to a conveyance roller that conveys a sheet and rotates once in synchronization with one rotation of the conveyance roller. Can be. The cut mark is always designed to be detected within the range of the active period of the window signal 1101. A cut mark sense signal 1102 indicating that a cut mark has been detected appears as shown.

  In this system, the time t (t1, t2,..., Tn) 1103 from the rise of the waveform of the window signal 1101 (the start timing of the active period) to the rise of the waveform of the cut mark sense signal 1102 is measured. The measured time t is sequentially stored in the memory means of the control unit 140C.

  FIG. 11 is a graph schematically showing the history at time t1103 shown in FIG. The abscissa indicates the variable accumulated for each result of using the cutter means, and the ordinate indicates the time t. The variable accumulated for each result of using the cutter means on the horizontal axis can be associated with the usage time of the printing apparatus in addition to the number of times the cutter means is used.

  With reference to FIG. 11, the relationship between the change in time t1103 and the degree of risk of occurrence of control failure of the printing apparatus will be described. In FIG. 11, a cross mark 1201 is a history plotted every time the cut mark sense signal 1102 appears within the active period range of the window signal 1101 and represents a distribution of time t. In the figure, a warning level 1202 indicated by a dotted line parallel to the horizontal axis defines a level of time t that is equal to or greater than a certain rate at which there is a risk of device malfunction. Similarly, an error level 1203 indicated by a dotted line parallel to the horizontal axis in the figure indicates a level at time t at which a malfunction of the apparatus will occur.

  The relational expression 1206 indicated by a solid line is derived from the plotted history points by a statistical method. The start point Sp1205 is a start point at which the history starts to be plotted, and is required for calculating this relational expression. In the present embodiment, the relational expression is represented by a primary expression y = ax + b. As a phenomenon in which the history point draws a trajectory represented by such a relational expression, for example, the conveyance roller that conveys the sheet wears out or paper dust adheres to the conveyance roller. There may be a phenomenon in which the transport amount of the transported sheet is lower than the design amount. The warning point Wp1204 is a point where the solid line of the relational expression 1206 intersects the dotted line of the warning level 1202.

  An inference line 1207 indicated by a dotted line indicates a locus that will be drawn based on the relational expression 1206 when the numerical value on the horizontal axis is increased. The error point Ep1208 is the intersection of the dotted line of the inference line 1207 and the dotted line of the error level 1203. The intersection of the perpendicular line drawn from the error point Ep1208 and the X axis indicates a usage situation in which a malfunction such as a sheet cutting error may occur in the printing apparatus due to deterioration of parts over time (usage time of the apparatus, the number of times of cutting by the cutter, etc.) The predicted value of is shown.

  In the present invention, during the sheet cutting operation, the time t from the rise of the waveform of the window signal (the start timing of the active period) to the rise of the waveform of one cut mark sense signal, that is, the cut mark detection time t is detected. , Accumulate that data. In this example, according to the relational expression 1206 in which statistical processing is performed in time series, the cut mark detection time at that time changes from the cut mark detection time at the start (for example, the start point Sp1205) as the apparatus usage time becomes longer. The state of doing is expressed.

  In the present embodiment, the timing for determining the constant of the relational expression 1206 is the timing of the warning point Wp at which the cut mark detection time t has reached a predetermined warning level. Up to that point, the constants of the relational expressions assumed in data processing are set as temporary constants. When reaching that point, the relational expression 1206 is determined. Thereafter, based on the established relational expression 1206, the usage state of the apparatus (the usage time of the printing apparatus, the number of times of cutting the sheet by the cutter, etc.) that the cut mark detection time t is predicted to reach the error level 1203 is calculated. Ask.

  The remaining time during which the apparatus can be used stably as it is can be obtained from the predicted use situation of the apparatus and the actual use of the apparatus. First, the difference between the predicted usage status of the device at the error point Ep1208 obtained by calculation and the actual usage record of the device at the time when the error point Ep is calculated is obtained. From the obtained difference, the time from the time point to the time point (error time) at which malfunction (error) will occur in the apparatus is calculated. Next, the time until the end of the print job closest to the time is subtracted from the calculated time, and the obtained time is notified to the user. When starting the next print job, the user is allowed to understand that there may be an error time before the time at which the print job is finished, and the interface is then used to select whether to perform the print job.

  As described above, in the configuration of the present invention, the timing at which a malfunction that is a problem in use in the printing apparatus may occur is predicted from the change in the timing at which the cut mark is detected. Based on the prediction, the user can end the print job and maintain the printing apparatus. Therefore, it is possible to prevent a problem level of malfunction.

  In the present embodiment, the present invention has been described using an example in which the relational expression shows a graph with a rising right. The graph goes up to the right, indicating that the transport roller that transports the sheet needs more time to send the expected amount due to slippage or abrasion due to the adhesion of paper dust. Yes.

  The present invention can also be applied to a case where the relational expression shows a graph of a downward trend (not shown). An example of the case where the graph falls to the right is a case where a phenomenon that the peripheral speed of the conveying roller is improved, such as the thickening of the conveying roller due to adhesion of paper dust, has occurred.

  The relational expression may be an expression indicating a graph other than a straight line such as a logarithmic curve or a quadratic curve by a statistical method (not shown).

  In the above embodiment, the conveyance roller has been described as an example of the conveyance mechanism. However, the present invention is not limited to this, and can be applied to a case where the conveyance mechanism is a conveyance belt or other forms.

4 Print unit 6 Cutter unit 14 (14K, 14C, 14M, 14Y) Print head 17 Cut mark sensor 18 First cutter 19 Second cutter 100 Image 101 Margin area 102 Cut mark 140 (140K, 140C, 140M, 140Y) Control unit 1101 Window signal 1102 Cut mark sense signal 1103 Cut mark detection time t (t1, t2,..., Tn)
5020 Host computer (host)
5040 encoder

Claims (6)

A print unit for printing on the conveyed sheet;
A sensor for detecting a cut mark formed on the sheet;
A cut portion for cutting the sheet based on detection by the sensor;
A measuring means for measuring the transport amount of the transported sheet;
A printing apparatus comprising:
The sensor detects the cut mark within an active period set based on measurement by the measuring means,
A printing apparatus comprising: a predicting unit that predicts a malfunction of the printing apparatus according to a change in a length of time from the start timing of the active period to the detection of the cut mark.   The printing apparatus according to claim 1, wherein the prediction unit includes a storage unit that accumulates the measured length of time.   The prediction means reads the length of time accumulated in the storage means in the order of the accumulated time series, performs calculation by a statistical method for each predetermined period, and changes the time length over time The printing apparatus according to claim 2, wherein the tendency is calculated.   The predicting means predicts a time point when the length of the time is estimated to reach a level at which the malfunction of the printing apparatus occurs from a tendency of the calculated time length to change over time. The printing apparatus according to claim 3.   The predicting unit estimates a remaining time during which the printing apparatus can operate stably from a time point when it is estimated that the predicted malfunction level of the printing apparatus is reached. 5. The printing apparatus according to 4. A print unit for printing on the conveyed sheet;
A sensor for detecting a cut mark on the sheet;
A cut portion for cutting the sheet based on detection by the sensor;
A measuring means for measuring the transport amount of the transported sheet;
A method for controlling a printing apparatus comprising:
By the sensor, the cut mark is detected within an active period set based on measurement by the measuring means,
According to a change in the length of time from the start timing of the active period to the detection of the cut mark, predicting a malfunction of the printing apparatus,
A method of controlling a printing apparatus, comprising: estimating a remaining time during which the printing apparatus can stably operate from the predicted occurrence of the malfunction.

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