JP2023088749A - Recording device, control method of recording device and program - Google Patents

Abstract

To accurately align positions of two ends of a page image on a front surface with positions of two ends of a page image on a rear surface when performing two-sided printing.SOLUTION: A recording device for recording a front surface image on a front surface of a continuous sheet, inverting the sheet and recording a rear surface image on a rear surface of the sheet comprises: conveyance means which conveys the sheet; recording means which sequentially records a page image and a mark on the front surface or the rear surface; fixation means which fixes the image recorded on the sheet; detection means which detects the mark recorded on the sheet; inversion means which inverts the sheet; and control means which controls image correction for expanding/contracting the image length of the rear surface image on the basis of the detection result of the mark recorded on the front surface. The control means executes rear surface conveyance processing on the basis of the determination result on whether or not the image correction to all the page images included in the rear surface image is complete.SELECTED DRAWING: Figure 4

Description

The present disclosure relates to a printing apparatus that prints on both sides of a printing medium.

In a recording apparatus typified by an inkjet printer, so-called double-sided printing may be performed in which recording is performed on the first side and then recording is performed on the second side, which is the back side of the first side. In a recording apparatus that performs double-sided printing, it is important to match the position of the image on the first side with the position of the image on the second side in order to maintain the quality of the product.

Specifically, when printing on the second side, it is necessary to align the print start position with the edge of the image on the first side. However, even if the leading edge position of the image is correct, if the paper expands or contracts due to the influence of printing after printing on the first side, printing on the second side without considering the expansion or contraction effect of the image on the first side will result in the The position of the trailing edge of the image on the second side is displaced from the position of the trailing edge of the image on the first side. If the position of the image on the first side and the position of the image on the second side are misaligned, the image is cut off on either the first side or the second side when the paper is cut to a predetermined length. There are problems such as the problem that the image is overwritten, and the problem that a blank space is created.

In order to deal with such problems, a conventional recording apparatus records marks on paper, and uses detection of the marks to determine the print start position as the leading edge of the image on the second side. There is a way to align it. Also, the length of the first image printed on the first side may deviate from the planned value by the time the printing of the second image on the second side starts due to the expansion and contraction of the paper due to the effect of wetness or dryness. and correcting the length of the second image is known.

In the recording apparatus of Patent Document 1, when printing on the first side, a cue mark indicating the printing start position of the first image on the first side is printed while the paper is being conveyed, and the cue mark is used as a reference to print the first image. Print one image. After that, when printing on the second side, which is the reverse side of the first side, the second image for the second side corrected based on the expansion/contraction information about the expansion/contraction of the paper stored in the storage unit is displayed as a cue mark. is printed on the basis of Also, as the page spacing, the spacing between the detected cue marks in the paper transport direction is calculated, and the difference between the size on the image data and the size of the actually printed image is calculated and stored in the storage unit. Correct the expansion/contraction information.

JP 2020-49663 A

However, in the recording apparatus disclosed in Patent Document 1, the cue mark detection section for aligning the front end position of the image detects the mark for correcting the expansion/contraction information. in the recording section. In a recording apparatus having such a configuration, when performing expansion/contraction information correction during paper conveyance for printing on the second side of a continuous sheet (specifically, a roll sheet), among a plurality of page images to be printed on the second side, There is a problem that the expansion/contraction information correction cannot be made in time for the first sheet.

Therefore, in view of the above problem, an embodiment of the present invention provides two edge positions of a front page image and a back page image for all ejected pages when double-sided printing is performed using a continuous sheet. The purpose is to precisely align the positions of the two ends of the .

An embodiment of the present invention is a recording apparatus for recording a front side image on the front side of a continuous sheet, inverting the sheet, and recording a back side image on the back side of the sheet, comprising a conveying means for conveying the sheet; , recording means for sequentially recording one or more page images and marks on the front surface or the back surface; fixing means for fixing the image recorded on the sheet; a first detecting means provided on the downstream side in the conveying direction of the sheet, a reversing means for reversing the sheet, and the mark recorded on the surface by the first detecting means. and a control means for controlling image correction for extending or shortening the image length of the back side image based on the detection result of the above, wherein the control means controls all of the one or more page images included in the back side image. and executing a rear surface conveying process for conveying the reversed sheet to the recording unit based on a determination result as to whether or not the image correction has been completed. .

According to one embodiment of the present invention, when double-sided printing is performed using a continuous sheet, the positions of the two edges of the front page image and the positions of the two edges of the back page image are determined for all ejected pages. It is possible to match the position of the part with high precision.

Schematic diagram showing the internal configuration of the printing device Block diagram of control unit Diagram for explaining operations in single-sided print mode and double-sided print mode Diagram showing back side image length correction processing considering front side image elongation due to sheet elongation due to front side printing Control Flow of Image Correction Processing of Second Image for Second Surface in First Embodiment Control Flow of Image Correction Processing of Second Image for Second Surface in Second Embodiment

[First embodiment]
The inkjet printing apparatus according to this embodiment will be described below. This printing apparatus is a high-speed line printer that uses long continuous sheets and is capable of both single-sided printing and double-sided printing. The sheet used in this embodiment is assumed to be a continuous sheet longer than the length of a repeated print unit (referred to as unit image, page image, etc.) in the transport direction. Further, the printing apparatus of the present embodiment is suitable for printing a large number of sheets in, for example, a print laboratory. In this specification, even if a plurality of small images, characters, or blanks are mixed in the area of one print unit (one page), the items contained in the area are collectively referred to as "one unit image (one-page image)”. In other words, a "unit image" means an image of one print unit (one page) when a plurality of pages are sequentially printed on a continuous sheet. It should be noted that the unit image may be simply referred to as an "image". The length of the unit image differs depending on the paper size of the sheet to be printed. For example, an L size photograph has a unit image length of 135 mm in the sheet conveying direction, and an A4 size photograph has a unit image length of 297 mm in the sheet conveying direction.

The present embodiment can be widely applied to printing apparatuses in general, such as printers, multi-function printers, copiers, facsimile machines, and manufacturing apparatuses for various devices. The printing process may be any method such as an inkjet method, an electrophotographic method, a thermal transfer method, a dot impact method, or a liquid development method. Further, the present embodiment is applicable not only to printing apparatuses but also to sheet conveying apparatuses that perform various processes (recording, processing, coating, irradiation, reading, inspection, etc.) while conveying roll sheets.

<Configuration of printing device>
FIG. 1 is a schematic cross-sectional view showing the internal configuration of the printing apparatus. The printing apparatus of the present embodiment is capable of printing on the first surface of the sheet and the second surface on the back side of the first surface using a rolled sheet, that is, so-called double-sided printing. ing. The printing apparatus includes therein a sheet supply section 1, a decurling section 2, a skew correction section 3, a printing section 4, an inspection section 5, a cutter section 6, an information recording section 7, a drying section 8, and a reversing section 9. , discharge/conveyance unit 10, sorter unit 11, discharge unit 12, and control unit 13. A sheet is conveyed by a conveying mechanism including a pair of rollers and a belt along a sheet conveying path indicated by a solid line in the drawing, and processed in each unit. At an arbitrary position on the sheet conveying path, the side closer to the sheet feeding section 1 is called "upstream", and the opposite side is called "downstream".

The sheet supply unit 1 is a unit for holding and supplying a continuous sheet wound in a roll. The sheet supply unit 1 can accommodate two rolls R1 and R2, and is configured to selectively pull out and supply sheets. Note that the number of rolls that can be stored is not limited to two, and one roll or three or more rolls may be stored. In addition, as long as it is a continuous sheet, it is not limited to a rolled sheet. For example, a continuous sheet having perforations for each unit length may be folded and stacked for each perforation and stored in the sheet supply section 1 .

The decurling section 2 is a unit that reduces the curling (warp) of the sheet supplied from the sheet supplying section 1 . In the decurling part 2, two pinch rollers are used for one driving roller, and the sheet is curved so as to give a curl in the opposite direction to pass through, thereby applying a decurling force and reducing the curl.

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

The printing section 4 is a sheet processing section for performing print processing on the conveyed sheet by the print head 14 from above to form an image. That is, the printing section 4 is a processing section that performs predetermined processing on the sheet. The print unit 4 also includes a plurality of transport rollers that transport sheets. The print head 14 is a line type print head in which ink jet type nozzle rows are formed in a range covering the maximum width of the sheet that is assumed to be used. A plurality of print heads are arranged in parallel along the transport direction. In this example, the print head 14 corresponds to seven colors of C (cyan), M (magenta), Y (yellow), LC (light cyan), LM (light magenta), G (gray), and K (black). It has 7 printheads. Note that the number of colors and the number of print heads are not limited to seven, and any integer may be used. In addition, as the inkjet method, a method using a heating element, a method using a piezoelectric element, a method using an electrostatic element, a method using a MEMS element, or the like can be adopted. Each color ink is supplied from an ink tank to the print head 14 via an ink tube.

A mark reader 18b is provided between the skew correction section 3 and the printing section 4 and immediately before the upstream side of the printing section 4 in the sheet conveying direction. The mark reader 18b is a reflective optical sensor that optically reads the reference marks recorded on the sheet. The mark reader 18b 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 the RGB components of the light from the illuminated sheet surface. The mark can be read based on changes in the signal level of the photodetector or by image analysis of the imaging data. A mark reader similar to the mark reader 18b is provided in the reversing section 9 and the cutter section 6 as well. In this embodiment, for convenience, the mark reader of the reversing section 9 is the first mark reader 18a, the mark reader between the skew correction section 3 and the printing section 4 is the second mark reader 18b, and the cutter section 6 mark reader is referred to as a third mark reader 18c.

A mark reader 18b provided between the skew correction section 3 and the printing section 4 is used when printing on the second side, and reads the reference mark recorded on the first side of the sheet conveyed from the reversing section 9. , reading from the opposite side to the printing side.

The inspection unit 5 optically reads the inspection pattern, image, etc., recorded on the sheet by the printing unit 4 with a scanner, and inspects the nozzle state of the print head, the sheet conveying state, the image position, etc., to ensure that the image is recorded correctly. It is a unit for determining whether or not The scanner has a CCD image sensor or a CMOS image sensor.

The cutter unit 6 is a unit having a cutter 19 for cutting the sheet after image recording into a predetermined length. Cutter 19 consists of two mechanical cutters 19a, 19b. The upstream cutter 19a and the downstream cutter 19b efficiently cut off the blank area between the images formed on the sheet, as will be described later. The cutter unit 6 further includes the above-described mark reader 18c for reading marks recorded on the sheet, a plurality of conveying rollers for feeding the sheet to the next process, and an edge sensor 20a for skipping images. I have. Also, a trash box 17 is provided in the vicinity of the cutter section 6 . The trash can 17 stores small sheet pieces whose blank areas are cut off by the cutters 19a and 19b and discharged as garbage. The cutter unit 6 is provided with a sorting mechanism for discharging the cut sheet to the trash box 17 or transferring it to the original conveying path.

The information recording unit 7 records unique information (print information) such as a serial number and date corresponding to printing (output) in an area where no image is recorded (referred to as an image non-recording area) on the cut sheet. is a unit. Recording by the information recording unit 7 is performed by recording characters, codes, and the like by an inkjet method, a thermal transfer method, or the like. On the upstream side of the information recording section 7 and the downstream side of the cutter section 6, an edge sensor 20b for detecting the leading edge of the cut sheet is provided. That is, the edge sensor 20b detects the edge of the sheet between the cutting position by the cutter section 6 and the recording position by the information recording section 7. FIG. The timing of recording information in the information recording section 7 is controlled based on the detection timing of the edge sensor 20b.

The drying unit 8 is a unit that heats the sheet on which an image has been recorded by the printing unit 4 and dries the applied ink in a short time, thereby fixing the image recorded on the sheet. Inside the drying section 8, hot air is applied from at least the lower surface side to the passing sheet to dry the ink-applied surface. The drying method is not limited to applying hot air, and may be a method of irradiating the sheet surface with electromagnetic waves (ultraviolet rays, infrared rays, etc.).

The sheet conveying path from the sheet supply section 1 to the drying section 8 is called 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 up and reversing the front and back surfaces of the continuous sheet on which front side printing has been completed when double-sided printing is performed. The reversing section 9 is a path for supplying the sheet that has passed through the drying section 8 to the printing section 4 again. ) is provided in the middle. The reversing unit 9 has a rotating winding rotor (drum) for winding the sheet. A continuous sheet whose surface has been printed and which has not been cut is temporarily taken up by the take-up rotor. When the winding is completed, the winding rotating body rotates in the reverse direction, and the wound sheet is delivered in reverse order to the winding, supplied to the decurling section 2, and sent to the printing section 4. - 特許庁Since this sheet is turned upside down, the back side of the sheet can be printed by the printing section 4. - 特許庁A more specific operation of double-sided printing will be described later. In FIG. 1, the reversing unit 9 of the winding type provided with a winding rotating body (drum) is illustrated as an example of the reversing unit, but the method of the reversing unit is not limited to this. This embodiment can also be applied to a recording apparatus having a reversing section of any other system such as a switchback system.

The discharging/conveying 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 conveyed sheet to the sorter unit 11 . The discharging/conveying section 10 is provided on a path (referred to as a third path) different from the second path on which the reversing section 9 is provided. A path switching mechanism having a movable flapper is provided at a path branch position to selectively guide a sheet conveyed along the first path to either the second path or the third path.

The sorter section 11 and the discharge section 12 are provided on the side of the sheet supply section 1 and at the end of the third path. A sorter unit 11 is a unit for sorting printed sheets into groups as needed. The sorted sheets are discharged to a discharge section 12 consisting of a plurality of trays. In this manner, the printing apparatus has a layout in which the third path passes under the sheet feeding section 1 and the sheet is discharged on the side opposite to the printing section 4 and the drying section 8 with the sheet feeding section 1 interposed therebetween. there is

As described above, the sheet feeding section 1 to the drying section 8 are provided in order on the first path. The tip of the drying section 8 is branched into a second path and a third path, the second path is provided with an inverting section 9 in the middle, and the tip of the inverting section 9 joins the first path. A discharge part 12 is provided at the end of the third path.

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

FIG. 2 is a block diagram showing the configuration of the control section 13. As shown in FIG. A dashed area in the figure indicates a controller included in the control section 13 , and the controller has a CPU 201 , a ROM 202 , a RAM 203 , an HDD 204 , an image processing section 207 , an engine control section 208 and an individual unit control section 209 . A CPU 201 is a central processing unit, and comprehensively controls the operation of each unit of the printing apparatus. The ROM 202 stores programs to be executed by the CPU 201, fixed data required for various operations of the printing apparatus, and the like. 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. HDD 204 is a hard disk drive. The HDD 204 stores programs to be 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 for the user to input instructions and provide information to the user. Includes output.

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

The host device 16 is a device that serves as a supply source of image data for printing by the printing device. Host device 16 may be a general-purpose or dedicated computer, or dedicated imaging equipment such as an image capture device having an image reader, a digital camera, a photo storage, or the like. When the host device 16 is a computer, an OS, application software for generating image data, and a printer driver for a printing device are installed in a storage device included in the computer. It should be noted that it is not essential to implement all of the above processes by software, and some or all of them may be implemented by hardware.

<Basic operation during printing>
Next, the basic operation of the printing apparatus at the time of printing will be described. Since the operation differs between the single-sided print mode and the double-sided print mode, each will be described.

<<Basic operation in single-sided print mode>>
FIG. 3A is a diagram for explaining the operation in single-sided print mode. A sheet supplied from the sheet supply unit 1 and processed by the decurling unit 2 and the skew correcting unit 3 is printed on the surface (first surface) by the printing unit 4 . Images (unit images) of a predetermined unit length in the conveying direction are 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 mark for cutting is recorded in the blank area by the printing section 4 . The printed sheet passes through the inspection section 5 and is cut into unit images by the cutter 19 in the cutter section 6 based on the mark detection result by the third mark reader 18c. Print information is recorded on the back surface of the cut sheet by the information recording unit 7 as needed. Then, the cut sheets are conveyed one by one to the drying section 8 and dried. After that, the sheets are sequentially discharged and stacked on the discharge section 12 of the sorter section 11 via the discharge conveying section 10 . On the other hand, the sheet left on the side of the printing section 4 as a result of cutting the last unit image is sent back to the sheet supply section 1, and the sent-back sheet is taken up on the roll R1 or R2.

Thus, in simplex printing, the sheet is processed to pass through the first and third passes and not through the second pass. To summarize the above, in the single-sided print mode, the following sequences (1) to (6) are executed under the control of the control section 13 .
(1) A sheet is sent out from the sheet feeding section 1 and supplied to the printing section 4 .
(2) The printing unit 4 repeats printing of unit images and cutting marks on the first side (surface) of the supplied sheet.
(3) The sheet is repeatedly cut 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 section 8 one by one.
(5) Each sheet that has passed through the drying section 8 is discharged to the discharge section 12 through the third path.
(6) Cut the last unit image and feed the sheet left on the printing section 4 side back to the sheet feeding section 1 .

<<Basic operation in double-sided print mode>>
FIG. 3B is a diagram for explaining the operation in the double-sided print mode. In double-sided printing, a print sequence for the front side (first side) is followed by a print sequence for the back side (second side). In the first print sequence for the front side, the operations of the units from the sheet supply unit 1 to the inspection unit 5 are the same as those of the single-sided print mode described above, except for the printing of marks. In the double-sided print mode, the mark for position correction is printed instead of the mark for cutting described above at the time of front side printing. Although the purpose of the position correction marks is different from that of the cutting marks, the printed marks themselves are reference marks for optical detection by the mark reader 18 in the same way as the cutting marks used in the cutter section. is. The continuous sheet is conveyed to the drying section 8 without cutting in the cutter section 6 . After the ink on the surface is dried in the drying section 8, the sheet is guided to the path (second path) on the side of the reversing section 9 instead of the path (third path) on the side of the discharging/conveying section 10. FIG. In the second path, the sheet is taken up by the take-up rotor of the reversing section 9 rotating in the forward direction (counterclockwise direction in FIG. 3B). When the print section 4 completes printing on the planned surface, the cutter section 6 cuts the trailing edge of the print area of the continuous sheet. With the cutting position as a reference, the continuous sheet on the downstream side (printed side) in the conveying direction passes through the drying section 8 and is completely wound up to the sheet rear end (cutting position) by the reversing section 9 . On the other hand, at the same time as this winding, the continuous sheet left on the upstream side of the cutting position in the conveying direction (on the side of the printing unit 4) is fed to the sheet supply unit so that the leading edge (cutting position) of the sheet does not remain in the decurling unit 2. 1, the sheet is wound onto roll R1 or R2. This rewinding avoids collision with the sheet being fed again in the following print sequence for the back side.

After the front side printing sequence described above, the back side printing sequence is switched to. The winding rotating body of the reversing section 9 rotates in the opposite direction (clockwise direction in FIG. 3(b)) to the winding time. The edge 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 sent to the decurling section 2 along the path indicated by the dashed line in the figure. In the decurling section 2, the curl imparted to the sheet by the winding rotary member is corrected. That is, the decurling section 2 is provided between the sheet feeding section 1 and the printing section 4 on the first path and between the reversing section 9 and the printing section 4 on the second path. It is a common unit that works. The sheet whose front and back sides are reversed is sent to the printing section 4 via the skew correcting section 3, and the unit image and the cut mark are printed on the back side of the sheet. The printed sheet passes through the inspection section 5 and is cut into predetermined unit lengths by the cutter section 6 . Since the cut sheet is printed on both sides and the information is recorded on the surface, the information recording section 7 does not record the information. The cut sheets are conveyed one by one to the drying section 8 and sequentially discharged and stacked on the discharge section 12 of the sorter section 11 via the discharge conveying section 10 .

Thus, in double-sided printing, the sheet is processed so as to pass through the first path, the second path, the first path, and the third path in this order. To summarize the above, in the double-sided print mode, the following sequences (1) to (11) are executed under the control of the control section 13. FIG.
(1) A sheet is sent out from the sheet feeding section 1 and supplied to the printing section 4 .
(2) The printing unit 4 repeats printing of unit images and position correction marks on the first side of the supplied sheet.
(3) The sheet printed on the first side is conveyed and passed through the drying section 8 .
(4) The sheet that has passed through the drying section 8 is led to the second path and wound up on the winding rotating member of the reversing section 9 .
(5) After the repeated printing on the first surface is completed, the cutter section 6 cuts the sheet after the last printed unit image.
(6) The cut sheet is wound around the winding rotor until the end of the cut sheet passes through the drying section 8 and reaches the winding rotor. At the same time, the sheet left on the side of the printing section 4 after being cut is sent back to the sheet feeding section 1 .
(7) After the winding is completed, the winding rotor is rotated in the reverse direction, and the sheet is again supplied to the printing section 4 via the second path.
(8) The printing unit 4 repeats printing of unit images and cutting marks on the second surface of the supplied sheet.
(9) The cutter unit 6 repeats cutting of the sheet for each unit image printed on the second surface.
(10) The sheets cut for each unit image are conveyed one by one and passed through the drying section 8 .
(11) Each sheet that has passed through the drying section 8 is discharged to the discharge section 12 through the third path.

<Alignment control of leading and trailing edges of images in double-sided printing>
Next, alignment control of the leading and trailing edges of an image in double-sided printing will be described below. First, image length correction processing for matching the image lengths of the first and second surfaces will be described.

The sheet with the image printed on the first side passes through the inspection section 5 , the cutter section 6 and the drying section 8 and reaches the second path between the drying section 8 and the reversing section 9 . A second path between the drying section 8 and the reversing section 9 is provided with a first mark reader 18a on the first surface reading side. The sheet is given moisture by printing in the printing section 4, and then passes through the drying section 8 to evaporate the moisture. The sheet expands and contracts due to this change in water content and the action of heat. Therefore, it is desirable that the first mark reader 18a be provided between the drying section 8 and the reversing section 9 and after the drying section 8 at a position where the expansion and contraction of the sheet is as stable as possible. Therefore, the first mark reader 18a is provided immediately before the reversing section 9 in this embodiment.

The first mark reader 18a detects a mark between images as a mark for position correction, and acquires the detection interval between the detected mark and the next detected mark as the actually recorded mark interval. . Then, the obtained mark interval is compared with the theoretical (data) mark interval calculated from the original print data, and from the difference between the two, the second surface on the back side of the page between the marks is printed. Calculate the image length expansion/contraction correction value of the image to be printed. Then, using this calculated correction value, expansion/contraction correction of the image length of the image data of the second side is performed so that the image length of the first side and the image length of the second side, which is the back side of the first side, are substantially the same. do. By repeatedly performing this correction process for all marks in the same manner, it is possible to perform the correction process for all the images of the second-side pages corresponding to the respective first-side pages.

Here, concrete actual image length correction processing will be described. FIG. 4 is a diagram showing back side image length correction processing in consideration of sheet elongation due to the influence of front side printing.

Let A be the mark interval before and after the image page with respect to the image length a of a certain surface. After printing in the printing section 4, if the actual mark interval becomes A' due to the effect of the sheet stretching, the difference A'-A will appear if the original image length a is printed on the back side of the corresponding page. Therefore, it is necessary to correct the image length of the back side image. Here, the image length of the back side image is corrected by evenly changing the scale of the image in the sheet conveying direction at a ratio of A'/A with respect to the original image length a. In addition, by sequentially performing the same correction processing on other pages, it is possible to perform image length correction of the back side image individually following the expansion and contraction of the sheet due to the influence of printing on the first side. high-precision image correction can be realized for each page.

Next, the control of tip position alignment will be described. After the sheet is conveyed for printing on the second surface, which is the back surface, the sheet passes through the decurling section 2 and the skew correction section 3, and is printed by the above-described second mark reader 18b when printing on the first surface. Detect marks. Using this mark as a cue mark, the image front end position as the print start position (recording start position) of each unit image to be printed on the second surface is determined. Specifically, the sheet may be fed by a predetermined transport amount from the mark detection position to the first nozzle of the first head. In this way, after the mark is detected, when the conveyance of a predetermined amount is completed, by controlling to start printing on the second side, the end portion of the first image on the first side and the The leading edge of the second image can be aligned. For the sake of explanation in this specification, the image printed on the first surface is referred to as "first image" and "front image", and the image printed on the second surface is referred to as "second image" and "back image". defined as The second mark reader 18b sequentially detects the marks provided between the images on the second and subsequent pages in the same manner, thereby controlling the positions of the leading edges of the images on each page.

Thus, the result of mark detection by the second mark reader 18b is used to correct the leading edge position of the second image with respect to the second surface. This makes it possible to match the end position of the first image with respect to the first surface and the leading end position of the second image with respect to the second surface. Also, using the mark detection result by the first mark reader 18a, image length correction processing is performed for all pages. As a result, the image length of the first image on the first surface and the image length of the second image on the second surface can be accurately matched. Also, the trailing edge position of the first image and the trailing edge position of the second image can be aligned. Therefore, when the sheet is cut for each image by the cutting unit 6 and a single sheet as a product is discharged, it is possible to prevent the problem that the image is cut off or the problem that a margin appears.

In addition, when the above-described correction processing is performed, the image length of the back side may shift by a certain constant magnification as a whole. As an example, there is a case where the sheet conveying speed around the first mark reader 18a provided on the second path and the sheet conveying speed in the printing section 4 deviate. In this case, the image length calculated by the mark detection in the second path and the image length calculation based on the mark detection is equal to the deviation of the sheet conveying speed between the periphery of the first mark reader 18a and the printing section 4. It deviates from the expected value. As a result of the shift occurring as a shift in image correction at a constant magnification, a positional shift between the front side image and the back side image is continuously generated. Therefore, in such a case, the conveying amount around the first mark reader 18a and the conveying amount of the printing unit 4 are acquired in advance, and the conveying amount difference is calculated when correcting the image length for printing on the second surface. (that is, the transport amount correction value is calculated). Then, the transport amount correction value acquired as a result of the transport amount difference correction process is feedback-controlled (reflected) in the image length correction process. As a result, it is possible to eliminate image defects caused by deviations in the amount of transport between the mark detection section and the print section.

Based on the above, as image correction control processing in the present embodiment, expansion correction processing for a second image to be printed on the second side in consideration of sheet expansion and contraction after printing on the first side will be described with reference to FIG. . Specifically, this image correction control process is the process from the arrival of the sheet on the second path after printing of the first side (front side) to the completion of image correction processing of the second image on the second side (back side). is.

When the sheet reaches the second path after front side printing is completed, the CPU 201 starts the sheet winding by the reversing section 9 in step S101. Note that the winding process started in this step is referred to as "sheet winding process". Also, hereinafter, "step S~" is abbreviated as "S~".

In S<b>102 , the CPU 201 uses the first mark reader 18 a to start detecting the marks between the images as position correction marks while the sheet is wound and conveyed to the reversing section 9 . Note that the detection process started in this step will be referred to as "position correction mark detection process".

In S103, the CPU 201 starts correction processing for the above-described second image data to be printed on the second surface. Note that the image correction processing started in this step will be referred to as "second image correction processing".

In S<b>104 , the CPU 201 determines whether the sheet winding process is completed based on whether the trailing edge of the continuous sheet cut by the cutter section 6 has reached the reversing section 9 after front side printing is completed. do. When the trailing edge of the continuous sheet cut by the cutter unit 6 reaches the reversing unit 9, it is determined that the sheet winding process has ended, and the process proceeds to S105. On the other hand, if the trailing edge of the continuous sheet cut by the cutter unit 6 does not reach the reversing unit 9, it is determined that the sheet winding process has not ended, and the determination process of S104 is continued.

In S105, the CPU 201 terminates the position correction mark detection process. Also, the process of conveying the sheet in the forward direction with the first surface (front surface) facing upward (that is, the state in which the first surface faces the print head 14) ends. Note that the transport process that ends in this step is referred to as "surface transport process".

In S106, the CPU 201 determines whether or not the aforementioned second image correction processing has been completed for all pages to be printed from now on. If it is determined that all pages have been processed, the process proceeds to S107. On the other hand, if it is determined that the processing has not been completed for all pages, the second image correction processing and the determination processing of S106 are continued.

In S<b>107 , the CPU 201 starts the process of forwardly conveying the sheet with the second surface (back surface) facing upward (that is, the second surface facing the print head 14 ). Note that the transport process started in this step will be referred to as "back surface transport process". Incidentally, in the present embodiment, in the rear surface conveying process started in this step, the trailing edge of the continuous sheet in conveying the first surface (front surface) becomes the leading edge of the continuous sheet.

<Effects of this embodiment>
Through the series of image correction control processes described above, the image length correction process for the second image to be printed on the second surface can be reliably completed in time for the first printing on the second surface.

[Second embodiment]
A second embodiment will be described below. In the following description, contents similar to those of the first embodiment will be omitted as appropriate, and different contents will be mainly described.

FIG. 6 is a flow chart showing the control flow of image correction processing for correcting the image length of the second image printed on the second surface in this embodiment.

Each process from S201 to S205 is the same as in the first embodiment (S101 to S105 in FIG. 5).

However, this embodiment differs from the first embodiment in the process after the position correction mark detection process in S205 is completed. A detailed description will be given below.

In S206, the CPU 201 starts the back surface conveying process. As described above, in the present embodiment, unlike the first embodiment, the rear surface conveying process is started even if the second image correction process for the second image is not completed (see S105 to S107 in FIG. 5).

In S<b>207 , the CPU 201 determines whether or not the sheet has reached the printing section 4 . If the determination result of this step is true, the process proceeds to S208. On the other hand, if the determination result of this step is false, the determination processing of S207 is continued.

In S208, the CPU 201 determines whether or not the second image correction processing has been completed for all pages. If the determination result of this step is true, the process proceeds to S210. On the other hand, if the determination result of this step is false, the process proceeds to S209.

In S209, the CPU 201 temporarily stops the rear surface transport process. By this step, the printing device enters a print standby state.

In S210, the CPU 201 executes a rear surface conveying process. In this step, when the back surface conveying process is stopped in S209 as a result of the determination result of S208 becoming false, the back surface conveying process is restarted (NO in S208→S209→YES in S208→S210). Incidentally, if S209 is not passed, the rear surface conveying process is continued (YES in S208→S210).

<Effects of this embodiment>
In the control flow of this embodiment, the sheet is fed to the printing unit 4 and waits. The image correction process for the page can be completed.

[Other embodiments]
The present disclosure provides a program that implements one or more functions of the above-described embodiments to a system or device via a network or storage medium, and one or more processors in a computer of the system or device reads and executes the program. It can also be realized by processing to It can also be implemented by a circuit (for example, ASIC) that implements one or more functions.

4 printing unit 8 drying unit 9 reversing unit 13 control unit 18a first mark reader

Claims (17)

A recording apparatus for recording a front side image on the front side of a continuous sheet, inverting the sheet, and recording a back side image on the back side of the sheet,
a conveying means for conveying the sheet;
recording means for sequentially recording one or more page images and marks on the front surface or the back surface;
fixing means for fixing the image recorded on the sheet;
a first detection unit provided downstream of the fixing unit in the sheet conveying direction and configured to detect the mark recorded on the sheet;
reversing means for reversing the sheet;
control means for controlling image correction for extending or shortening the image length of the back side image based on the detection result of the mark recorded on the front side by the first detection means;
has
The control means causes the conveying means to record the reversed sheet based on a determination result as to whether or not the image correction has been completed for all of the one or more page images included in the back side image. Execute the back side conveying process to convey by the means,
A recording device characterized by: the control means determines whether or not the image correction has been completed for all of the one or more page images included in the back side image;
2. The recording apparatus according to claim 1, wherein: The control means is
if it is determined that the image correction has not been completed for all of the one or more page images included in the back side image, without starting the back side conveying process;
when it is determined that the image correction has been completed for all of the one or more page images included in the back side image, the back side conveying process is started;
3. The recording apparatus according to claim 2, wherein: The control means is
starting the back surface conveying process before determining whether or not the image correction has been completed for all of the one or more page images included in the back surface image;
determining whether or not the image correction has been completed for all of the one or more page images included in the back side image when the reversed sheet reaches the recording means;
3. The recording apparatus according to claim 2, wherein: The control means is
if it is determined that the image correction has not been completed for all of the one or more page images included in the back side image, stopping the back side conveying process;
if it is determined that the image correction for all of the one or more page images included in the back side image has been completed, continuing or restarting the back side conveying process;
5. A recording apparatus according to claim 4, characterized in that: The mark is recorded between an arbitrary page image and the next page image of the arbitrary page image,
6. The recording apparatus according to any one of claims 1 to 5, characterized in that: The first detection means detects the mark during conveyance of the non-inverted sheet on which the surface image is recorded on the surface;
The control means calculates an expansion/contraction correction value for each of the one or more page images included in the back side image based on the difference between the mark spacing actually recorded on the front side and the mark spacing on the data. ,
7. The recording apparatus according to any one of claims 1 to 6, characterized by: The control means performs the image correction on each of the one or more page images included in the back side image by using the expansion/contraction correction value corresponding to each of the one or more page images,
In the image correction, each of the one or more page images included in the back side image is evenly expanded or contracted in the conveying direction of the sheet according to the corresponding expansion or contraction correction value.
8. A recording apparatus according to claim 7, characterized in that: wherein the first detection means is provided between the fixing means and the reversing means;
9. A recording apparatus according to any one of claims 1 to 8, characterized in that: The first detection means is provided immediately before the upstream side of the reversing means in the sheet conveying direction,
10. The recording apparatus according to claim 9, characterized by: further comprising second detection means for detecting the mark recorded on the sheet;
The second detection means is provided immediately before the upstream side of the recording means in the sheet conveying direction,
11. The recording apparatus according to any one of claims 1 to 10, characterized by: When recording the back side image on the back side, the mark recorded on the front side is detected by the second detection means,
The control means determines an image leading end position as a recording start position of each of the one or more page images included in the back side image, based on the detection result by the second detection means.
12. The recording apparatus according to claim 11, wherein: The control means calculates a transport amount correction value based on the difference between the transport amount detected by the first detection means of the transport means and the transport amount detected by the second detection means of the transport means, and reflecting the amount correction value in the image correction;
13. A recording apparatus according to claim 11 or 12, characterized in that: The sheet is a roll sheet,
14. The recording apparatus according to any one of claims 1 to 13, characterized by: The length of each of the one or more page images recorded on the back surface is substantially the same as the length of any of the page images recorded on the front surface corresponding to each of the one or more page images.
15. The recording apparatus according to any one of claims 1 to 14, characterized by: A control method for a recording apparatus for recording a front side image on the front side of a continuous sheet, inverting the sheet, and recording a back side image on the back side of the sheet, comprising:
The recording apparatus includes a conveying unit that conveys the sheet, a recording unit that sequentially records one or more page images and marks on the front surface or the back surface, and an image recorded on the sheet. fixing means for fixing the sheet; first detecting means for detecting the mark recorded on the sheet and provided downstream of the fixing means in the conveying direction of the sheet; reversing means for reversing the sheet; a control means for controlling image correction for extending or shortening the image length of the back side image based on the detection result of the mark recorded on the front side by the first detection means;
The control means causes the conveying means to record the reversed sheet based on the determination result as to whether or not the image correction has been completed for all of the one or more page images included in the back side image. Having a step of executing a back surface conveying process for conveying by means,
A control method characterized by: A program for causing a computer to perform the method according to claim 16.

Images