JP2015189180A - Image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the amount of image data for test pattern image formation to be stored by an image formation device.SOLUTION: An image formation device forms a test pattern image on a sheet in order to adjust the discharge timing of ink droplets. The test pattern image has a plurality of pattern component rows in a main scanning direction in a sub-scanning direction being a sheet conveyance direction. The image data indicating the test pattern image comprises the common pattern image data and plural symbol image data. The common pattern image data indicates one row of the pattern components. The i-th symbol image data indicates one row of the symbol (identification number of the pattern component) formed adjacently to the i-th row pattern component. The image formation device makes a recording head carry out the discharge operation of the ink droplets based on the i-th symbol image data and the common pattern image data every arrival of the sheet to plural formation devices (the i-th formation position) in the sub-scanning direction.

Description

  The present invention relates to an image forming apparatus.

  2. Description of the Related Art Conventionally, there is known an image forming apparatus that forms an image on a sheet by reciprocating a recording head that discharges ink droplets in the main scanning direction while conveying the sheet in the sub scanning direction. In this image forming apparatus, the image formed on the sheet by conveying the recording head in the first direction along the main scanning direction, and the image formed on the sheet by conveying the recording head in the second direction opposite to the first direction. If the positional deviation occurs between the two, the quality of the image formed on the sheet may be deteriorated. As a conventional apparatus, an apparatus having a function of forming a test pattern image on a sheet is known in order to suppress such a decrease in image quality.

  According to this image forming apparatus, for example, information indicating the formation state of a test pattern image on a sheet is acquired by a reading operation by a scanner or by an input operation from a user, and based on this information, ink droplet ejection control is performed. By correcting the control parameter, it is possible to suppress misalignment and form a good quality image on the sheet.

  In addition, as an image forming apparatus for forming a test pattern image on a sheet, individual test pattern image data is stored for each sheet size, and the test pattern image data corresponding to the size of the sheet to be conveyed is used for the sheet. An image forming apparatus that forms a test pattern image is known (see, for example, Patent Document 1).

JP-A-6-199017

  By the way, in the process of being conveyed in the sub-scanning direction, for example, the sheet moves while changing its bending or deformation according to the structure of the conveyance path. For this reason, in order to form a high-quality image on a sheet, a plurality of pattern components dispersed in the sheet are formed as a test pattern image, and information representing these formation states is used to correct control parameters. Is preferred.

  However, in the method of storing test pattern image data of an image size for one sheet in the image forming apparatus for each sheet size, it is necessary to provide a large capacity memory in the image forming apparatus in order to store the test pattern image data Occurs.

  SUMMARY An advantage of some aspects of the invention is that it provides a technique capable of reducing the amount of image data for test pattern image formation to be stored in an image forming apparatus.

  The image forming apparatus according to the first aspect of the present invention includes a recording head, a transport unit, a control unit, and a storage unit. The recording head ejects ink droplets, and the transport unit transports the recording head to reciprocate the recording head along the main scanning direction. The storage unit stores image data representing a test pattern image for adjusting the ink droplet ejection operation.

  The control unit controls the recording head and the conveyance unit to form an image on the sheet conveyed from the upstream in the sub-scanning direction. The control unit causes the transport unit to transport the recording head each time the transport position of the sheet in the sub-scanning direction reaches each of a plurality of forming apparatuses that are test pattern image forming positions and extend in the sub-scanning direction. Then, the recording head is caused to perform an ink droplet ejection operation based on the image data. By this control, the control unit forms a test pattern image based on the same image data on the sheet for each of the formation positions.

  According to this image forming apparatus, test pattern images are formed on a plurality of forming apparatuses along the sub-scanning direction of the sheet, and image data of an image size for one sheet is stored for the formation of the test pattern image. Instead, the image data to be repeatedly used is stored for each forming position. Therefore, according to the present invention, the amount of image data to be stored by the image forming apparatus for forming the test pattern image is suppressed, and the test pattern image having pattern components dispersed on the sheet with a small amount of image data. Can be formed.

  The storage unit can store, as the image data, image data having a width in the main scanning direction corresponding to a maximum size sheet on which the image forming apparatus can form an image. In this case, the control unit converts the image data read from the storage unit into printing data corresponding to the width of the sheet forming the test pattern image, and records the ink droplet ejection operation based on the printing data. By causing the head to execute, a test pattern image can be formed on the sheet.

  For example, the control unit generates the printing data by setting the data area in the image data where no sheet exists at the position where the test pattern image is formed as a mask area that prohibits the ink droplet ejection operation. Can be configured. According to this configuration, the control unit can easily and appropriately execute the processing operation for forming the test pattern image on the sheet by controlling the recording head with respect to sheets of various sizes.

  As another example, the control unit may be configured to generate the printing data by deleting, from the image data stored in the storage unit, a data area where no sheet exists at a position where the test pattern image is formed. In this case, the control unit can adjust the formation position of the test pattern image based on the printing data in the sheet by correcting the ejection position of the ink droplet, and can form the test pattern image on the sheet. .

  In addition, the image forming apparatus can be provided with a sensor for detecting both side edges along the sub-scanning direction of the sheet. In this case, the control unit sets, in the mask pattern area, a data area corresponding to an image formed outside the area sandwiched between both side edges detected using the sensor, among the test pattern images represented by the image data. Can do. If the sensor is used, it is possible to set the mask region more appropriately than when the position information of both side edges is acquired from the user.

  In addition, the image forming apparatus may be configured such that a structure for sandwiching a sheet is disposed at two points between which an image forming position by the recording head is sandwiched in the sub-scanning direction. The position where the test pattern image is formed by this image forming apparatus may include the following points. That is, in the plurality of formation positions, the first position where the sheet is sandwiched at the upstream point among the two points, but not sandwiched at the downstream point, the second position where the sheet is sandwiched at both the two points, And at least two of the third positions where the seat is clamped at the downstream point but not at the upstream point may be included.

  When the test pattern image for adjusting the ejection operation of the ink droplet is formed at a plurality of positions where the bending or deformation of the sheet changes in the sheet conveyance process, it is useful for adjusting the ejection operation. There may be cases where the sheet is bent or deformed between the first position, the second position, and the third position. Therefore, if the formation position is determined as described above, a test pattern image more meaningful for adjusting the ejection operation can be formed on the sheet.

In addition, the image forming apparatus may be configured such that at least one of the two points is provided with a corrugated structure that sandwiches the sheet in a state where the sheet is deformed into a waveform in the main scanning direction.
In the image forming apparatus of the present invention, in the sub-scanning direction, a structure for sandwiching the sheet is arranged at two points sandwiching the image forming position by the recording head, and the upstream side point and the image in the two points in the sub-scanning direction are arranged. A configuration in which a corrugated structure is disposed between the forming position and the forming position may be employed. The position where the test pattern image is formed by the image forming apparatus may include the following points.

  That is, in the plurality of formation positions, the first position, the second position, and the position where the sheet is sandwiched at the downstream point while the sheet is not sandwiched at the upstream point and the sheet is sandwiched in the corrugated structure. There may be included at least two of the three positions and the fourth position where the sheet is held at the downstream point but not held at the upstream point and the sheet is not held even in the corrugated structure. In particular, the formation position may include two or more positions including the third position and the fourth position. If the formation position is determined in this way, a meaningful test pattern image can be formed on the sheet for the same reason as described above.

  The image forming apparatus according to the second aspect of the present invention includes a recording head, a transport unit, a control unit, and a storage unit. The image forming apparatus displays image data representing a test pattern image as the image data. Image data having a width in the main scanning direction corresponding to the maximum size sheet that can be formed is stored.

  In this image forming apparatus, the control unit converts the image data read from the storage unit into print data corresponding to the width of the sheet on which the test pattern image is formed, and prints the print head while transporting the recording head to the transport unit. A test pattern image is formed on a sheet by causing the recording head to perform an ink droplet ejection operation based on the data.

  According to this image forming apparatus, in order to form a test pattern image on each of different sized sheets, it is not necessary to store image data for each sheet size in the storage unit in advance. Therefore, the amount of image data to be stored for forming the test pattern image can be reduced.

1 is a block diagram illustrating a schematic configuration of an image forming apparatus. FIG. 6 is a top view illustrating a configuration of a paper transport mechanism. 3A is a configuration diagram around the corrugated structure forming body as viewed from the direction E in FIG. 2, and FIG. 3B is a configuration diagram around the discharge roller as viewed from the direction F in FIG. . 4A shows the trajectory of the ink droplet when the carriage is transported in the FWD direction by a broken line, and FIG. 4B shows the trajectory of the ink droplet when the carriage is transported in the RVS direction. It is a figure shown with a broken line. 5A is a diagram showing a test pattern image having a plurality of pattern constituent elements distributed and arranged on a sheet, and FIG. 5B is a diagram showing a detailed configuration of the pattern constituent elements. (C) is a figure showing the detailed structure of the block image which a pattern component has. FIG. 6A is a diagram illustrating a control parameter group for each sheet size stored in the EEPROM, and FIG. 6B is a diagram illustrating a configuration of test pattern image data. It is a flowchart showing the test pattern output process which a control unit performs. It is a flowchart showing the printing data generation process which a control unit performs. FIG. 9A is a diagram showing the positional relationship between the pattern component array indicated by the common pattern image data and the paper, and FIG. 9B is formed on the paper in the non-mask area and the mask area. It is a figure which shows the correspondence with a pattern component. It is a figure explaining the conversion method of the process target data at the time of print data generation.

  Embodiments of the present invention will be described below with reference to the drawings. An image forming apparatus 1 according to the present exemplary embodiment illustrated in FIG. 1 is a so-called inkjet printer, and includes a paper transport unit 10, an image forming unit 50, a control unit 90, and a user interface 100.

  The paper transport unit 10 transports the paper Q supplied from the upstream of the paper transport path in the sub-scanning direction and discharges it to a paper discharge tray (not shown). The paper transport unit 10 includes a paper transport mechanism 20, a PF motor 41, a motor driver 43, an encoder 45, a signal processing circuit 47, and a registration sensor 49.

  The paper transport mechanism 20 operates by receiving power from the PF motor 41 that is a DC motor, and transports the paper Q in the sub-scanning direction. The PF motor 41 is driven by a motor driver 43. The motor driver 43 operates according to a control signal from the control unit 90 and drives the PF motor 41.

  As shown in FIG. 2, the paper transport mechanism 20 includes a pair of transport rollers 21, a platen 22, a plurality of corrugated structure forming bodies 24, a plurality of ribs 25, a pair of paper discharge rollers 27, and a spur roller 28. , 29. In FIG. 2, in order to easily illustrate the configuration of the paper transport mechanism 20, the carriage 60 disposed above the platen 22 and the elements mounted on the carriage 60 are indicated by broken lines, and the paper transported along the platen 22. Q is indicated by a one-dot chain line.

  The pair of transport rollers 21 are provided so as to face each other along the main scanning direction upstream of the image forming position where the image is formed on the paper Q by the recording head 61 in the sub scanning direction. In FIG. 2, only one transport roller 21 is illustrated, but it should be understood that the other transport roller 21 is disposed so as to overlap the illustrated transport roller 21. One of the pair of transport rollers 21 is driven by a PF motor 41, and the other transport roller 21 is driven to rotate by the driven transport roller 21.

  The pair of transport rollers 21 sandwich the paper Q supplied from the upstream of the paper transport path, and transport the paper Q in the sub-scanning direction orthogonal to the main scanning direction. The paper transport mechanism 20 may be configured to include a paper feed unit that supplies the paper Q placed on the paper feed tray to the transport roller 21 one by one, but the detailed description and illustration thereof are omitted in this specification. To do.

  The platen 22 is disposed so as to face the ink ejection surface of the recording head 61 downstream of the transport roller 21 in the sub-scanning direction. The paper Q that has passed through the transport roller 21 is transported along the upper surface of the platen 22 in the sub-scanning direction.

  The plurality of corrugated structure forming bodies 24 are arranged so as to face the upper surface of the upstream end of the platen 22 in the sub-scanning direction, and are arranged at substantially equal intervals along the main scanning direction. The paper Q transported from the transport roller 21 passes between the platen 22 and the corrugated structure forming body 24 and moves downstream in the sub-scanning direction. As shown in FIG. 3A, the corrugated structure forming body 24 presses the paper Q passing therethrough from above by the pressing surface 24A. On the other hand, the paper Q is supported from below by the platen 22.

  The plurality of ribs 25 are provided on the upper surface of the platen 22. These ribs 25 are arranged at substantially equal intervals in the main scanning direction in a state where the ribs 25 are arranged in a region between adjacent corrugated structure forming bodies 24 in the main scanning direction, specifically, at a substantially middle point of the region. . Each of the ribs 25 extends from an upper end of the platen 22 in the sub-scanning direction toward the downstream side in a state of protruding from the upper surface of the platen 22 to above the pressing surface 24A of the corrugated structure forming body 24. That is, the rib 25 pushes up the paper Q passing through this position to above the pressing surface 24A.

  That is, in the image forming apparatus 1 of this embodiment, the corrugated structure forming bodies 24 and the ribs 25 that are alternately arranged in the main scanning direction deform the paper Q into a waveform in the main scanning direction downstream of the transport roller 21 in the sub scanning direction. Thus, a corrugated structure is formed, and the paper Q passing through the corrugated structure is deformed into a wave shape in the main scanning direction, as shown in FIG.

  The pair of paper discharge rollers 27 are provided on the downstream side of the platen 22 in the sub scanning direction so as to face each other along the main scanning direction. Each of the paper discharge rollers 27 is configured such that roller components 27B having a diameter larger than that of the shaft 27A are arranged on the shaft 27A at substantially equal intervals. As shown in FIG. 3B, one paper discharge roller 27 includes a roller component 27B at the same position in the main scanning direction as the roller component 27B of the other paper discharge roller 27 facing the other. These roller components 27B are disposed at substantially the same position as the ribs 25 in the main scanning direction.

  Accordingly, the pair of paper discharge rollers 27 conveys the paper Q conveyed from the upstream in the sub-scanning direction downstream of the sub-scanning direction with the portion located at the same position as the plurality of ribs 25 in the main scanning direction. One of the paper discharge rollers 27 (the upper paper discharge roller 27) can be configured in a spur shape so that the ink that has landed on the paper Q is less likely to adhere. The other of the paper discharge rollers 27 (the lower paper discharge roller 27, specifically, the lower shaft 27A) is driven by a PF motor 41.

  The spur roller 28 is provided at a position corresponding to the downstream side of the paper discharge roller 27 in the sub-scanning direction and above the passage region of the paper Q. The spur roller 28 has a configuration in which spurs 28B having a diameter larger than that of the shaft 28A are arranged on the shaft 28A at substantially equal intervals. The spur 28B is disposed at substantially the same position as the corrugated structure forming body 24 in the main scanning direction, in other words, at a substantially intermediate point between the roller components 27B adjacent in the main scanning direction. Further, as shown in FIG. 3B, the spur roller 28 is such that the lower surface of the spur 28B is positioned below the upper surface of the roller component 27B provided in the paper discharge roller 27 positioned below the paper Q. To be arranged.

  In addition, the spur roller 29 is provided at a position corresponding to the upper side of the passage region of the paper Q, downstream of the spur roller 28 in the sub-scanning direction. The spur roller 29 has a configuration in which spurs 29B having a diameter larger than that of the shaft 29A are arranged on the shaft 29A at substantially equal intervals. The spur 29B is disposed at substantially the same position as the spur 28B in the main scanning direction.

  Accordingly, the sheet Q is pushed down by the spurs 28B and 29B in a state of being sandwiched between the pair of paper discharge rollers 27 in a region downstream of the platen 22 in the sub scanning direction, and is deformed in a wave shape in the main scanning direction. In this state, the paper Q is further conveyed downstream in the sub-scanning direction.

  In addition, the encoder 45 is provided to indirectly detect the paper transport amount Z in the sub-scanning direction by the paper transport mechanism 20. The encoder 45 is constituted by, for example, a rotary encoder provided on the rotation shaft of the PF motor 41, and a pulse signal (A phase and B phase signal) generated every time the PF motor 41 rotates by a predetermined amount is signaled as an encoder signal. Input to the processing circuit 47. The rotation amount Y of the PF motor 41 corresponds to the paper transport amount Z. The signal processing circuit 47 detects the rotation amount Y and the rotation speed Vy of the PF motor 41 based on this encoder signal, and inputs the detected values of the rotation amount Y and the rotation speed Vy to the control unit 90.

  Further, the registration sensor 49 is provided at a position slightly away from the transport roller 21 upstream in the sub-scanning direction. In FIG. 2, the registration sensor 49 is provided, for example, on a line PR along the main scanning direction, and is used to detect the leading edge and the trailing edge of the paper Q passing through the line PR. The registration sensor 49 inputs an ON signal as a detection signal to the control unit 90 when the sheet Q exists on the line PR, and inputs an OFF signal as a detection signal to the control unit 90 when the sheet Q does not exist on the line PR. To do. Therefore, the detection signal input to the control unit 90 is switched from the off signal to the on signal when the leading edge of the paper Q passes the line PR, and is turned off from the on signal when the trailing edge of the paper Q passes the line PR. Switch to signal.

  As a function for detecting the leading edge position of the paper Q, the control unit 90 detects the distance Z1 from the line PR to the paper leading edge of the PF motor 41 detected by the signal processing circuit 47 when the registration sensor 49 switches from the off signal to the on signal. It has a function of detecting the rotation amount Y1 as an index. Based on the difference between this rotation amount Y1 and the current value of the rotation amount Y detected by the signal processing circuit 47, the control unit 90 detects the distance Z1 at that time.

  Further, as a function for detecting the rear end position of the paper Q, the control unit 90 detects the distance Z2 from the line PR to the rear end of the paper by the signal processing circuit 47 when the registration sensor 49 switches from the on signal to the off signal. It has a function of detecting the rotation amount Y2 of the PF motor 41 using an index. Based on the difference between this rotation amount Y2 and the current value of the rotation amount Y detected by the signal processing circuit 47, the control unit 90 detects the distance Z2 at that time.

  Next, the configuration of the image forming unit 50 will be described in detail. The image forming unit 50 conveys the carriage 60 in the main scanning direction in accordance with an instruction from the control unit 90, and causes the recording head 61 to eject ink droplets to form (print) an image on the paper Q on the platen 22. . As shown in FIG. 1, the image forming unit 50 includes a carriage 60 on which a recording head 61 and an optical sensor 65 are mounted, a head drive circuit 70, a carriage transport mechanism 80, a CR motor 81, a motor driver 83, An encoder 85 and a signal processing circuit 87 are provided.

  The carriage 60 has an optical sensor 65 mounted upstream in the sub-scanning direction, and a recording head 61 mounted downstream thereof. The recording head 61 is a so-called inkjet head, and ejects ink droplets from a plurality of nozzles formed on the ink ejection surface facing the platen 22 in accordance with a drive signal from the head drive circuit 70. The head driving circuit 70 drives the recording head 61 in accordance with a control signal from the control unit 90 and causes the recording head 61 to eject ink droplets.

  The optical sensor 65 is also called a media sensor, is controlled by the control unit 90, irradiates light from the light emitting unit (not shown) toward the platen 22, and the light receiving unit (not shown) emits incident light whose main component is reflected light. Detects the amount of light received. The detected value of the amount of received light is input to the control unit 90. Since the surface of the platen 22 is dark, the amount of received light shows a large value when the paper Q is below the optical sensor 65 and shows a small value when there is no paper Q below the optical sensor 65.

  Based on the change in the amount of received light detected by the optical sensor 65 and the position X of the carriage 60 detected using the encoder 85 when the carriage 60 is conveyed in the main scanning direction, the control unit 90 The positions X1, X2 in the main scanning direction of both side edges (left and right side edges) along the sub scanning direction of the paper Q placed on the platen 22 are specified.

  The carriage transport mechanism 80 operates by receiving power from a CR motor 81 that is a DC motor, and transports the carriage 60 in the main scanning direction. The CR motor 81 is driven by a motor driver 83. The motor driver 83 operates in accordance with a control signal from the control unit 90 and drives the CR motor 81.

  When the CR motor 81 rotates in the first rotation direction, the carriage transport mechanism 80 moves the carriage 60 in the first direction (hereinafter referred to as “FWD direction”) along the main scanning direction, as shown in FIG. Express. On the other hand, when the CR motor 81 rotates in the second rotation direction opposite to the first rotation direction, the carriage transport mechanism 80 moves the carriage 60 along the main scanning direction as shown in FIG. It is conveyed in a second direction (hereinafter referred to as “RVS direction”) which is the opposite direction to the FWD direction. The carriage 60 reciprocates along the main scanning direction by the operation of the carriage transport mechanism 80 that switches the transport direction of the carriage 60 according to the rotation direction of the CR motor 81. As the carriage 60 reciprocates, the recording head 61 and the optical sensor 65 reciprocate in the main scanning direction.

  The encoder 85 is a linear encoder including an encoder scale 85A and a sensor 85B. The encoder scale 85A is provided in the conveyance path of the carriage 60 in the main scanning direction, and is fixedly arranged with respect to the housing of the image forming apparatus 1. On the other hand, the sensor 85B is fixedly disposed on the carriage 60. That is, the encoder 85 reads the encoder scale 85A fixed to the housing by the sensor 85B that moves together with the carriage 60, so that each time the carriage 60 is transported by a predetermined amount, the pulse signal (A phase and B phase signal) is input to the signal processing circuit 87 as an encoder signal.

  The signal processing circuit 87 detects the position X and the speed Vx of the carriage 60 in the main scanning direction based on the encoder signal input from the encoder 85, and inputs the detected values of the position X and the speed Vx to the control unit 90. .

  In addition, the control unit 90 performs overall control of the entire image forming apparatus 1. The control unit 90 includes a CPU 91, a ROM 93, a RAM 95, an EEPROM 97, and an external interface 99. The external interface 99 realizes communication with the external device 3.

  The CPU 91 executes a process according to a program recorded in the ROM 93, and the RAM 95 is used as a work area when the process is executed. The EEPROM 97 is an electrically rewritable nonvolatile memory, and the EEPROM 97 stores various control parameters and setting parameters.

  The control unit 90 implements various functions necessary for the image forming apparatus 1 including control functions of the PF motor 41, the CR motor 81, and the recording head 61 by executing various processes by the CPU 91. The control unit 90 may be configured with a dedicated circuit for realizing various processes. That is, the control unit 90 can be configured to realize various functions by a combination of processing by software and processing by hardware.

  When the control unit 90 receives the image data to be printed from the external device 3 via the external interface 99, the control unit 90 and the paper transport unit 10 and the image so that an image based on the image data is appropriately formed on the paper Q. Control the forming unit 50.

  That is, the control unit 90 controls the PF motor 41 based on the detection values of the rotation amount Y and the rotation speed Vy input from the signal processing circuit 47 and the detection signal input from the registration sensor 49, so that the paper Q Is controlled in the sub-scanning direction. On the other hand, the control unit 90 controls the CR motor 81 and the recording head 61 based on the detected values of the position X and the speed Vx of the carriage 60 and the image data to be printed, which are input from the signal processing circuit 87. While controlling the carriage 60, the ink droplet ejection operation by the recording head 61 is controlled.

  Incidentally, the ink droplets ejected from the recording head 61 while the carriage 60 is transported do not land directly under the recording head 61 as shown in FIGS. 4A and 4B. For example, the ink droplets fall while having inertia in the main scanning direction due to the movement of the carriage 60 in the main scanning direction, and land at a point away from the ink droplet ejection point in the main scanning direction.

  The positional deviation between the ejection point and the landing point depends on the speed of the carriage 60 and the vertical distance D from the ink droplet ejection point to the paper Q. For this reason, in the image forming apparatus 1 of the present embodiment, while controlling the conveyance speed of the carriage 60, the ejection timing of the ink droplets is adjusted in accordance with the change in the peaks and valleys of the paper Q undulating in the main scanning direction by the corrugated structure. By adjusting, the landing point of the ink droplet is controlled, and an appropriate image is formed on the paper Q.

  However, in this embodiment, ink droplets are ejected while the carriage 60 is reciprocated to form an image on the paper Q. For this reason, unless the ink droplet ejection timing in the forward path and the backward path of the carriage 60 is adjusted accurately and appropriately, an image formed in the forward path of the carriage 60 and an image formed in the backward path of the carriage 60 adjacent thereto. Misalignment occurs in the main scanning direction, and the quality of the image formed on the paper Q deteriorates.

  For the purpose of avoiding such deterioration in quality, the image forming apparatus 1 according to the present embodiment forms a test pattern image on the paper Q, and obtains information representing the formation state from the user through the user interface 100 (test Pattern output function). The image forming apparatus 1 corrects the control parameter for controlling the ejection timing of the ink droplets based on the information representing the formation state obtained by the test pattern output function.

  Depending on the test pattern output function, a test pattern image including a group of pattern components as shown in FIG. 5A and a group of symbols printed adjacent to each pattern component is formed on the paper Q. Is done. According to FIG. 5A, the symbol is an identification number of a pattern component.

  In FIG. 5A, each pattern component is shown by a simple rectangular image, but this rectangular image is merely a schematic representation of the formation position of the pattern component on the paper Q. Specifically, each pattern component is configured as an image including a plurality of block images and a block number printed adjacent to each block image, as shown in the broken line area of FIG. . That is, the rectangular image showing each pattern constituent element shown in FIG. 5A corresponds to the image shown in the broken line area of FIG.

  More specifically, as shown in FIG. 5C, each block image is composed of an overlay of a first vertical stripe image and a second vertical stripe image. FIG. 5C conceptually shows in detail the configuration of the block images of block numbers 4, 5, and 6 shown in FIG.

  The first vertical stripe image is a vertical stripe image formed by causing the recording head 61 to eject ink droplets while the image forming apparatus 1 transports the carriage 60 in the FWD direction. In FIG. Indicated by multiple vertical stripes. The second vertical stripe image is a vertical stripe image formed by causing the recording head 61 to eject ink droplets while the image forming apparatus 1 transports the carriage 60 in the RVS direction. In FIG. It is shown by a plurality of vertical stripes. The first and second vertical stripe images are actually images in which the region of each vertical stripe is filled with ink droplets.

  As can be understood from FIG. 5C, the formation position of the second vertical stripe image with respect to the first vertical stripe image differs among the block images of block numbers 4, 5, and 6. In this embodiment, the image forming apparatus 1 changes the ejection timing of the ink droplets with respect to the first vertical stripe image when forming the second vertical stripe image between the block images for each pattern constituent element. A block image is formed. Specifically, a block image having an intermediate block number “5” is formed at the standard ejection timing, and block images having smaller block numbers “1” to “4” are reduced in number. It is formed at a discharge timing earlier than the standard. Further, block images with block numbers “6” to “9” larger than the intermediate block number “5” are formed at a discharge timing later than the standard as the number increases.

  For each pattern constituent element, the block number of the block image that is most inconspicuous that the user visually discriminates among the block image group constituting the pattern constituent element is used as information indicating the formation state of the pattern constituent element. Obtained from the user via the user interface 100. As a result, the image forming apparatus 1 determines a block image in which the ejection timing of the ink droplet is appropriate, and corrects the control parameter based on the determination result.

  According to the example shown in FIG. 5C, the block image with the block number 5 appears to the user's eyes as the most inconspicuous block image. This is because each of the vertical stripes constituting the second vertical stripe image is arranged between the vertical stripes constituting the first vertical stripe image, and the area corresponding to the block image is filled with almost no gap. In other words, the block image having a larger gap between the first vertical stripe image and the second vertical stripe image appears to the user's eyes as a block image in which the stripe is conspicuous.

  According to this embodiment, when the block number of the least noticeable block image is the intermediate block number “5”, the standard value is set as the control parameter and the carriage 60 is transported in the RVS direction. In this case, ink droplets are ejected from the recording head 61 at the standard ejection timing. On the other hand, if the block number of the least noticeable block image is smaller than the intermediate block number “5” (specifically, the block numbers “1” to “4”), the carriage 60 is conveyed in the RVS direction. The control parameter is adjusted so as to advance the ejection timing of the ink droplets at the time. Further, when the block number of the block image having the least noticeableness is larger than the intermediate block number “5” (specifically, the block numbers “6” to “9”), the carriage 60 is conveyed in the RVS direction. The control parameters are adjusted so as to delay the ejection timing of the ink droplets when the ink droplets are discharged.

  As shown in FIG. 6A, according to the present embodiment, a group of control parameters for each pattern component adjusted in this way is stored in the EEPROM 97 for each paper size. When the control unit 90 forms an image based on the image data provided from the external device 3 on the paper Q, the control unit 90 reads out a group of control parameters corresponding to the paper size to be fed, and uses the group of control parameters. By controlling the droplet discharge timing of the recording head 61, a high-quality image with little positional deviation is formed on the paper Q. The reason why the group of control parameters to be used is switched according to the paper size is that the deflection and deformation of the paper Q change according to the paper size, and appropriate control parameters change.

  Further, according to the present embodiment, the image data representing the test pattern image (hereinafter referred to as “test pattern image data”) is a single common to all paper sizes that can be handled by the image forming apparatus 1. The test pattern image data is stored in the ROM 93. When forming a test pattern image on the paper Q, the image forming apparatus 1 converts the test pattern image data into print data corresponding to the paper size of the image formation target, so that An appropriate test pattern image is formed on the paper Q.

  Here, the configuration of the test pattern image data will be described. As can be understood from FIG. 6B, the test pattern image data of the present embodiment is configured to include common pattern image data and a plurality of symbol image data. As shown in FIG. 5A, in this embodiment, five columns of pattern components are formed on one sheet of paper Q, and symbols () are adjacent to the pattern components of each column. Pattern component identification number). The column of the pattern constituent elements referred to here is a column along the main scanning direction.

  The common pattern image data is image data representing one column of pattern components, and is used in common when forming the pattern components of each column. The common pattern image data is image data used when the carriage 60 is transported in the FWD direction and is used when the carriage 60 is transported in the RVS direction, and FWD data for forming the first vertical stripe image. Image data and RVS data for forming a second vertical stripe image.

  On the other hand, among the plurality of symbol image data, the i-th symbol image data (i is any one of 1 to 5) represents one column of symbols formed adjacent to the i-th column pattern component. Image data. According to FIG. 5A, the first symbol image data is image data in which images representing numbers 1 to 17 are arranged in accordance with the geometric arrangement of adjacent pattern components.

  That is, in this embodiment, for each column, an image set including a column of pattern components and a column of symbols adjacent thereto is formed using common pattern image data and one symbol image data corresponding to the column. In the present embodiment, such a configuration of the test pattern image data is adopted. Therefore, as compared with the conventional case, the image data for one sheet corresponding to a certain vertical and horizontal size of the sheet Q is stored in the ROM 93. The amount of test pattern image data stored in the ROM 93 can be suppressed.

  In this embodiment, the test pattern image data for each paper size is not stored in the ROM 93, but a single test pattern image data common to various paper sizes is stored in the ROM 93. Therefore, the storage capacity required for the ROM 93 is increased. Can be suppressed.

  The test pattern image data stored in the ROM 93 is configured as image data suitable for the maximum size paper Q on which image formation is possible in the image forming apparatus 1. That is, the test pattern image data is patterned at positions corresponding to the peaks and valleys of the paper Q over the entire range in the main scanning direction with respect to the maximum size paper Q on which image formation is possible in the image forming apparatus 1. It is configured as image data having a horizontal width in which components can be arranged.

  More specifically, the test pattern image data is configured to include data representing whether or not ink droplets are ejected at all points in the main scanning direction in which ink droplets can be ejected in the image forming apparatus 1. The When the test pattern image is formed on the paper Q having a size smaller than the maximum size paper Q, the control unit 90 processes the data indicating whether or not the ink droplets are discharged at each point included in the test pattern image data to obtain the paper size. Print data that conforms to

  Next, processing executed by the control unit 90 when an instruction to output a test pattern image is input from the user via the operation unit 101 will be described. The user interface 100 includes an operation unit 101 including an operation key or a touch panel that can accept an input operation from a user, and a display unit 105 including a liquid crystal display or an organic EL display that can display various types of information to the user. Prepare.

  When the output instruction is input, the control unit 90 starts the test pattern output process shown in FIG. After the start, the control unit 90 controls the PF motor 41 so that the positions X1 and X2 of the both side edges along the sub-scanning direction of the sheet Q can be specified using the optical sensor 65 to the sheet transport mechanism 20. Then, the paper Q is conveyed downstream in the sub-scanning direction (S110).

  Thereafter, the control unit 90 controls the CR motor 81 to acquire the detected value of the received light amount from the optical sensor 65 while conveying the carriage 60 from end to end in the main scanning direction, and obtains this detected value. The data is temporarily stored in the RAM 95 in association with the position X of the carriage 60 at the time of detection. Based on the change in the amount of received light, the positions X1 and X2 in the main scanning direction of both side edges of the paper Q are specified (S120).

  After the specification, the control unit 90 controls the PF motor 41 and, based on the distance Z1, controls the paper Q until the leading position of the paper Q specified by the distance Z1 reaches a predetermined first formation position. The paper Q is conveyed downstream in the scanning direction, and the paper Q is stopped at the first formation position (S130).

  The i-th formation position (i is any one of 1 to 5) in this embodiment corresponds to the position where the i-th row image set is formed. At the first forming position, the paper Q is sandwiched by the transport roller 21 installed upstream of the image forming position in the sub-scanning direction, while the paper Q is not sandwiched by the paper discharge roller 27 downstream of the image forming position in the sub-scanning direction. Determined in position.

  Specifically, the first formation position is determined in an area where the leading edge of the sheet is positioned upstream of the line P1 shown in FIG. 2 in the sub-scanning direction and the sheet Q is disposed below the recording head 61. The line P1 corresponds to a point where the paper Q enters between the pair of paper discharge rollers 27. In other words, the first formation position is determined at a position where the leading edge of the sheet is arranged downstream of the line P4 in the sub-scanning direction. The line P4 corresponds to the downstream edge in the sub-scanning direction of the area where the paper Q is pressed against the platen 22 by the corrugated structure forming body 24.

  Thereafter, the control unit 90 reads out the first symbol image data and the common pattern image data, which are image data corresponding to the image set in the first column, from the ROM 93 and sets them as processing target data. Printing data is generated by applying processing based on the positions X1 and X2 of both side edges of the paper Q specified by using the optical sensor 65.

  Specifically, in S140, the print data generation process shown in FIG. 8 is executed. In the print data generation process, the control unit 90, based on the position X1 of the left edge of the paper, does not temporarily process the data to be processed and prints an image based on the data to be processed and the left edge of the paper. To determine whether there is a pattern component formed on the left edge of the paper Q (S510). That is, it is determined whether there is a pattern component that is arranged outside and inside the paper Q across the left edge.

  Each of the pattern constituent elements is composed of a group of block images and block numbers. Here, an area where the group of these block images and block numbers is formed (for example, surrounded by a broken line in FIG. 5B). Whether or not there is a pattern component formed on the left edge of the paper Q can be determined based on whether the left edge of the paper Q crosses the region). FIG. 9A shows the positional relationship between the pattern component and the left edge of the paper, on which the pattern component of the identification number “2” is formed on the left edge of the paper Q.

  If a negative determination is made in S510 (that is, No in S510, and there is no pattern component on the left edge of the paper Q at this time), the control unit 90 determines the left edge of the non-mask area of the processing target data. Then, it is set to a position that coincides with the left edge of the paper Q (S520), and the process proceeds to S530. On the other hand, if an affirmative determination is made in S510 (that is, Yes in S510, and a pattern component exists on the left edge of the paper Q at this time), the left edge of the non-mask area of the processing target data is set to the left edge of the paper. It is set to the left end of the pattern component located on the right of the pattern component formed on the edge (S525), and the process proceeds to S530. In FIG. 9B, as the pattern component with the identification number “2” exists on the left edge of the paper Q as shown in FIG. Is set at the left end of the pattern component having the identification number “3”.

  When the process proceeds to S530, the control unit 90, based on the position X2 of the right edge of the paper, does not temporarily process the data to be processed, and the pattern component and the right edge of the paper when the image based on the data to be processed is printed. The positional relationship is specified, and it is determined whether or not there is a pattern component formed on the right edge of the paper Q. The determination method here can employ the same method as the determination method in S510.

  If a negative determination is made in S530 (that is, No in S530 and there is no pattern component on the right edge of the paper Q at this time), the right edge of the non-mask area of the processing target data is set to the paper Q. The position coincides with the right edge (S540), and the process proceeds to S550. On the other hand, if an affirmative determination is made in S530 (that is, Yes in S530 and a pattern component exists on the right edge of the paper Q at this time), the right edge of the non-mask area of the processing target data is set to the right edge of the paper It is set to the right end of the pattern component located on the left side of the pattern component formed above (S545), and the process proceeds to S550. In FIG. 9B, as the pattern component having the identification number “16” exists on the right edge of the paper Q as shown in FIG. Is set at the right end of the pattern component having the identification number “15”.

  After shifting to S550, the control unit 90 determines the non-mask area in the processing target data defined by the left end of the non-mask area set in S520 or S525 and the right end of the non-mask area set in S540 or S545. The outside is determined as a mask area. Then, the control unit 90 converts the data in the processing target data corresponding to this mask area into a value of zero meaning that ink droplets are not ejected.

  As described above, the symbol image data and the common pattern image data constituting the test pattern image data are ink droplets for each point in the entire range in the main scanning direction in which the ink droplets can be ejected in the image forming apparatus 1. The data (values) indicating the presence or absence of the discharge are arranged.

  In S550, for the processing target data having such a configuration, all values corresponding to the points outside the non-mask area are converted to zero. In the example shown in FIG. 10, 2-bit data is assigned to each point, and a value of 00 means that no ink droplet is ejected, and a value of 01, a value of 10, and a value of 11 are the ink droplets. It means size. The numerical arrangement in the second column from the bottom in FIG. 10 is an enlarged view of a part of the arrangement of 2-bit data of the common pattern image data shown in the uppermost part of FIG. The numerical arrangement at the bottom of FIG. 10 shows the structure of print data after processing the enlarged data portion of the common pattern image data.

  According to this example, in step S550, the mask image is subjected to mask processing by converting the value 01, value 10, and value 11 of the mask region into the value 00. On the other hand, the value of each point in the non-mask area is not converted, and the processing target data is processed into the printing data. By this processing, the processing target data is converted into printing data from which image information outside the non-mask area is substantially erased.

  In S140, when the print data corresponding to the first row image set is generated by the above-described procedure, the control unit 90 controls the CR motor 81 to convey the carriage 60, while the print head 61 prints the print data. By performing the ink droplet ejection operation based on the print data, the first row of image sets represented by the print data is formed on the paper Q (S150). That is, in S150, among the image set of the first column represented by the test pattern image data in the area of the paper Q corresponding to the first formation position, the pattern components arranged on the paper without protruding outside the paper, and the pattern components An image set of symbols is formed.

  When the processing in S150 is finished, the control unit 90 controls the PF motor 41 to sub-feed the paper Q until the leading edge position of the paper Q specified by the distance Z1 reaches a predetermined second formation position. The paper Q is conveyed in the scanning direction, and the paper Q is stopped at the second forming position (S160).

  The second forming position is determined as a position where the paper Q is sandwiched between the transport roller 21 and the paper discharge roller 27. In this embodiment, the second forming position is such that the leading edge of the sheet is located downstream of the spur roller 29 in the sub-scanning direction and upstream of the flap mechanism provided downstream of the spur roller 29 in the sub-scanning direction. Determined. Although not described in detail, the flap mechanism is a mechanism for guiding the paper Q to the U-turn path instead of the paper discharge tray during double-sided printing, and is disposed on, for example, the line P2 shown in FIG. The flap mechanism affects the bending and deformation of the paper Q present at the image forming position. Note that, within the range of the paper size handled by the image forming apparatus 1 of the present embodiment, the rear end of the paper does not pass the transport roller 21 at the second forming position regardless of the paper size.

  Thereafter, the control unit 90 reads out the second symbol image data and the common pattern image data, which are image data corresponding to the image set in the second column, from the ROM 93 and sets them as processing target data, and print data for the processing target data. By executing the generation process (FIG. 8), similarly to S140, print data related to the image set of the second column in consideration of the positions X1 and X2 of both side edges of the paper Q is generated (S170).

  Thereafter, the control unit 90 causes the carriage transport mechanism 80 to transport the carriage 60, while causing the recording head 61 to perform an ink droplet ejection operation based on the print data, thereby causing the second column represented by the print data. Are formed on the paper Q (S180). That is, in S180, the pattern components arranged on the sheet without protruding outside the sheet in the image set of the second column represented by the test pattern image data in the area of the sheet Q corresponding to the second formation position and its An image set of symbols is formed.

  When the processing in S180 is completed, the control unit 90 proceeds to S190, controls the PF motor 41, and the leading edge position of the paper Q specified by the distance Z1 reaches a predetermined third formation position. Until the sheet Q is conveyed in the sub-scanning direction, the sheet Q is stopped at the third forming position. The third forming position is set at a position where the leading edge of the sheet has passed through the flap mechanism downstream in the sub-scanning direction, but the trailing edge of the sheet is upstream of the conveying roller 21 in the sub-scanning direction.

  Thereafter, the control unit 90 reads out the third symbol image data and the common pattern image data, which are image data corresponding to the image set of the third column, from the ROM 93 and sets them as processing target data, and uses the same principle as S140 and S170. Then, the processing target data is processed to generate print data (S200). Further, the third row image set represented by the printing data is formed on the paper Q by the same method as in S150 and S180 (S210).

  When the third row image set is formed in the area of the paper Q corresponding to the third forming position, the control unit 90 subsequently controls the PF motor 41 to start further conveyance of the paper Q downstream in the sub-scanning direction. (S220). In this conveyance process, it is determined whether the detection signal from the registration sensor 49 is switched to the off signal (S230). If the registration sensor 49 remains the on signal without switching to the off signal (No in S230). ), Continue paper transport. Then, when the registration sensor 49 remains in the ON signal for a certain period of time, an abnormality is detected (Yes in S240), the paper conveyance is terminated, and a paper jam is notified to the user through the display unit 105 (S340). Thereafter, the test pattern output process ends.

  On the other hand, if the registration sensor 49 is switched to the off signal before the predetermined time is exceeded (Yes in S230), the trailing edge position of the paper Q specified by the distance Z2 is determined in advance based on the distance Z2 obtained from that time. Until the fourth formation position is reached, the paper transport mechanism 20 transports the paper Q downstream in the sub-scanning direction, and stops the paper Q at the fourth formation position (S250).

  The fourth formation position is determined such that the rear end of the sheet passes through the transport roller 21 and is positioned downstream of the transport roller 21 in the sub-scanning direction and upstream of the line P3. The line P3 corresponds to the upstream edge in the sub-scanning direction of the region where the paper Q is sandwiched so as to be pressed against the platen 22 by the corrugated structure forming body 24. That is, the fourth formation position corresponds to a position where the paper Q is not sandwiched by the transport roller 21 but is sandwiched by the adjacent corrugated structure (corrugated structure forming body 24 and rib 25) and the paper discharge roller 27.

  Thereafter, the control unit 90 reads out the fourth symbol image data and the common pattern image data, which are image data corresponding to the image set of the fourth column, from the ROM 93 and sets them as the processing target data, and is the same as S140, S170, and S200. In principle, the processing object data is processed to generate print data (S260). Further, the fourth row image set represented by the printing data is formed on the paper Q by the same method as S150, S180, and S210 (S270).

  When the processing in S270 is completed, the control unit 90 controls the PF motor 41 to load the paper Q until the rear end position of the paper Q specified by the distance Z2 reaches a predetermined fifth forming position. The paper Q is conveyed in the sub-scanning direction, and the paper Q is stopped at the fifth formation position (S280). The fifth forming position is such that the rear end of the sheet passes through the conveying roller 21 and is positioned downstream of the line P4 in the sub-scanning direction, and the rear end of the sheet is upstream of the line P1 in the sub-scanning direction. 61 is defined in a region located below. That is, the fifth forming position corresponds to a position where the paper Q is not sandwiched between the transport roller 21 and the corrugated structure (corrugated structure forming body 24 and rib 25) adjacent thereto, but is sandwiched by the paper discharge roller 27.

  Thereafter, the control unit 90 reads out the fifth symbol image data and the common pattern image data, which are image data corresponding to the image set of the fifth column, from the ROM 93 and sets them as processing target data, and S140, S170, S200, and S260. Based on the same principle, the data to be processed is processed to generate print data (S290). Further, the fifth row image set represented by the printing data is formed on the paper Q by the same method as in S150, S180, S210, and S270 (S300).

  When the processing in S300 is completed, the control unit 90 causes the paper transport mechanism 20 to transport the paper Q to the paper discharge tray downstream in the sub-scanning direction (S310). As a result, the user can visually recognize the paper Q on which the test pattern image is formed.

  Thereafter, the control unit 90 displays a formation state reception screen on the display unit 105 (S320). The formation state reception screen is a screen for receiving an input operation of information indicating the formation state of each pattern component formed on the paper Q (the block number of the block pixel that is least noticeable). The user can input information representing the formation state of each pattern component by indirectly operating the reception screen by operating the touch panel or the operation key of the operation unit 101.

  When the input operation of the information indicating the formation state through the reception screen is completed, the control unit 90 controls the sheet size specified from the positions X1 and X2 on both side edges of the sheet Q detected using the optical sensor 65. A group of parameters and a group of control parameters stored in the EEPROM 97 are corrected according to the input information indicating the formation state (S330), and the test pattern output process is terminated.

  The image forming apparatus 1 of the present embodiment has been described above. In this image forming apparatus 1, the paper Q moves in the sub-scanning direction while changing the bending and deformation according to the structure of the paper conveyance path such as a corrugated structure. To do. For this reason, a plurality of pattern constituent elements distributed over the entire paper are formed by forming a row of pattern constituent elements at each of the first to fifth forming positions having different paper positions in the sub-scanning direction. Specifically, one formation position (first to fifth formation positions) is defined for each section having a boundary at a paper position where the deflection or deformation of the paper Q greatly changes with respect to the recording head 61, and a pattern is formed. Form a row of components.

  Then, by correcting the control parameters based on the information indicating the formation state of the pattern constituent elements, in the process in which the paper Q passes over the platen 22, the discharge timing is adjusted in accordance with the shape of the peaks and valleys of the paper Q. Ink droplets are discharged so that a high-quality image can be formed on the paper Q.

  Further, in this embodiment, in order to form pattern constituent elements distributed over the entire sheet, test pattern image data of the image size for one sheet is not stored in the ROM 93 but is commonly used at a plurality of formation positions. Test pattern image data including pattern image data is stored in the ROM 93.

  In this embodiment, each time the paper Q reaches each of a plurality of forming devices (first to fifth forming positions) along the sub-scanning direction, the carriage 60 on which the recording head 61 is mounted is transported and formed. The recording head is caused to perform an ink droplet ejection operation based on printing data obtained by processing the symbol image data corresponding to the position and the common pattern image data. Thereby, an image set based on the same pattern image data is formed on the paper Q for each forming position.

  Therefore, according to the present embodiment, the test pattern image shown in FIG. 4A, which is composed of a group of pattern constituent elements distributed and arranged on the entire sheet, while suppressing the data amount of test pattern image data that needs to be stored in the ROM 93. Can be appropriately formed on the paper Q.

  Furthermore, in this embodiment, test pattern image data (symbol image data and common pattern image data) having a width in the main scanning direction corresponding to the maximum size paper Q that can be imaged in the image forming apparatus 1 is stored in the ROM 93. To remember.

  Then, this image data is converted into printing data corresponding to the width of the paper Q forming the test pattern image (both side edge positions X1, X2), and the ink droplet ejection operation based on the printing data is performed. By causing the recording head 61 to execute the test pattern image, it is possible to satisfactorily form the test pattern image on the paper Q having different sizes based on the single test pattern image data.

  Therefore, according to this embodiment, it is not necessary to store the test pattern image data in the ROM 93 for each paper size, and the high-performance image forming apparatus 1 can be constructed at a low cost while suppressing the storage capacity of the ROM 93.

  In addition, according to the present embodiment, the paper Q is waved and held on the platen 22 by the corrugated structure constituted by the corrugated structure forming body 24 and the ribs 25, but before the rear end of the paper passes through the corrugated structure. The image set is formed on the paper Q at each of the fourth forming position and the fifth forming position after the rear end of the paper passes through the corrugated structure. Before and after the trailing edge of the sheet passes through the corrugated structure, the deflection and deformation of the sheet Q change greatly. According to this embodiment, the control parameters are adjusted according to the bending and deformation of the sheet Q before and after the passage. Can be appropriately performed based on the information indicating the formation state of the pattern constituent elements, so that a high-quality image can be formed on the paper Q.

  In addition, according to the present embodiment, when generating printing data suitable for the paper size, the data outside the non-mask area can be obtained without changing the width of the common pattern image data and the symbol image data in the main scanning direction. The value is converted to zero, which prohibits the ejection of ink droplets. Therefore, according to the present embodiment, even if test pattern image data is used as a common sheet for a plurality of paper sizes, print data adapted to the paper size can be generated easily and appropriately, and the corresponding pattern components can be obtained. It can be formed on paper Q.

As mentioned above, although the Example of this invention was described, this invention is not limited to the said Example, A various aspect can be taken.
For example, the control unit 90 may be configured to generate printing data in S550 as follows. That is, the control unit 90 can be configured to generate print data by cutting off data in a region not corresponding to the non-mask region from the processing target data (symbol image data and common pattern image data). In this case, by adjusting the ejection start position of the ink droplet based on the print data according to the amount of data that has been scraped off, the formation position of the image set represented by the print data is adjusted within the paper, The image set can be formed on the paper Q.

  In addition, in S550, the data for printing may be generated by adding data representing the non-mask area or the range of the mask area to the processing target data without changing the value of the processing target data. The present invention can also be applied to the image forming apparatus 1 that does not have a corrugated structure. Further, the symbols attached to the pattern constituent elements do not have to be numbers, and letters and figures such as alphabets can be used instead of the identification numbers.

  In addition, in S510, it is determined whether there is a pattern component on the edge of the paper Q. However, the present invention is not limited to this. For example, it may be determined whether the edge of the paper Q exists between two adjacent pattern components. When the edge of the paper Q exists between two adjacent pattern components, the pattern configuration in which the left edge of the non-mask area is positioned between the left edge and the right edge of the sheet, for example, corresponding to S525 What is necessary is just to set to the left end position of the pattern component nearest to the left edge of a sheet among elements. Further, for example, corresponding to S545, the right end of the non-mask area is set to the right end position of the pattern constituent closest to the right end edge of the sheet among the pattern constituent elements located between the left end edge and the right end edge of the sheet. That's fine.

  Further, as the above-described embodiment, an example has been described in which the landing point of the ink droplet is adjusted in accordance with the change in the peaks and valleys of the paper Q undulating in the main scanning direction by the corrugated structure. In order to achieve this object, the first vertical stripe image is formed by ejecting ink droplets from the recording head 61 conveyed in the FWD direction together with the carriage 60, and the second vertical stripe image is formed as the carriage 60. At the same time, the ink droplets are ejected from the recording head 61 conveyed in the RVS direction. However, the present invention may be applied to the formation of a test pattern image for the purpose of correcting the inclination of the recording head 61 with respect to the paper surface of the paper Q.

  An example of the test pattern image in this case will be described. The first image is formed by ejecting ink droplets from nozzles on the upstream side in the sub-scanning direction of the recording head 61 conveyed in the FWD direction together with the carriage 60. Next, in the sub-scanning direction, the paper Q is transported so that the first image forming position matches the nozzle forming position on the downstream side of the recording head 61 in the sub-scanning direction. Further, the second image is formed by ejecting ink droplets from the nozzles on the downstream side in the sub-scanning direction of the recording head 61 that is conveyed in the FWD direction together with the carriage 60. Then, with respect to the block image including the first image and the second image, a pattern component including nine block images in which the ejection timing of the ink droplets for forming the second image is varied in nine stages. Form. A test pattern image is formed by forming a pattern component row including 17 pattern components in one row for each of the first to fifth formation positions.

  The inclination of the recording head 61 with respect to the paper surface of the paper Q affects the height of the paper Q and the nozzles of the recording head 61 and has an influence on the landing position. Therefore, the above correction is necessary. However, if the inclination itself is simply obtained, it is not always necessary to form pattern components at the positions of the peaks and valleys as in the above embodiment.

[Correspondence]
Finally, the correspondence between terms will be described. The carriage 60, the carriage transport mechanism 80, the CR motor 81, and the motor driver 83 correspond to an example of a transport unit, and the ROM 93 corresponds to an example of a storage unit. The optical sensor 65 corresponds to an example of a sensor that can detect both side edges of the sheet.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 10 ... Paper conveyance unit, 20 ... Paper conveyance mechanism, 21 ... Conveyance roller, 22 ... Platen, 24 ... Corrugated structure formation body, 24A ... Pressing surface, 25 ... Rib, 27 ... Discharge roller, 27A ... shaft, 27B ... roller component, 28 ... spur roller, 28A ... shaft, 28B ... spur, 29 ... spur roller, 29A ... shaft, 29B ... spur, 41 ... motor, 43 ... motor driver, 45 ... encoder, 47 ... Signal processing circuit 49 ... registration sensor 50 ... image forming unit 60 ... carriage 61 ... recording head 65 ... optical sensor 70 ... head drive circuit 80 ... carriage transport mechanism 81 ... CR motor 83 ... motor driver 85 ... Encoder, 87 ... Signal processing circuit, 90 ... Control unit, 91 ... CPU, 93 ... ROM, 95 ... RAM, 97 ... EEP OM, 99 ... external interface, 100 ... user interface, 101 ... operation unit, 105 ... display unit, Q ... paper.

Claims (11)

A recording head for ejecting ink droplets;
A transport unit that reciprocates the recording head along a main scanning direction by transporting the recording head;
A control unit that forms an image on a sheet conveyed from upstream in the sub-scanning direction by controlling the recording head and the conveyance unit;
A storage unit for storing image data representing a test pattern image for adjusting the ink droplet ejection operation;
With
The control unit causes the transport unit to move to the transport unit whenever the transport position of the sheet in the sub-scanning direction reaches each of a plurality of forming apparatuses along the sub-scanning direction, which is the test pattern image forming position. By causing the recording head to perform an ink droplet ejection operation based on the image data while transporting the recording head, the test pattern image based on the same image data is transferred to the sheet at each formation position. An image forming apparatus comprising: The image data stored in the storage unit is image data having a width in the main scanning direction corresponding to a maximum size sheet on which image formation is possible in the image forming apparatus,
The control unit converts the image data read from the storage unit into printing data corresponding to the width of the sheet forming the test pattern image, and ejects the ink droplets based on the printing data. The image forming apparatus according to claim 1, wherein the test pattern image is formed on the sheet by causing the recording head to execute an operation. The control unit sets the data area in the image data in which the sheet does not exist at a position where the test pattern image is formed as a mask area that prohibits the ink droplet ejection operation. The image forming apparatus according to claim 2, wherein data is generated. A sensor for detecting both side edges of the sheet along the sub-scanning direction;
The control unit defines the data area corresponding to an image formed outside the area sandwiched between the both side edges detected using the sensor in the test pattern image represented by the image data, as the mask area. The image forming apparatus according to claim 3, wherein the image forming apparatus is set as follows. The test pattern image has a configuration in which a plurality of pattern components are arranged,
The control unit sets the mask region so that the mask region includes a data region in the image data corresponding to the pattern component straddling both side edges of the test pattern image represented by the image data. The image forming apparatus according to claim 4, wherein: In the sub-scanning direction, a structure for sandwiching the sheet is disposed at two points sandwiching an image forming position by the recording head,
The plurality of formation positions include a first position where the sheet is held at an upstream point of the two points, but is not held at a downstream point, and a second position where the sheet is held at both of the two points. The position and at least two of the third positions where the sheet is clamped at the downstream point but not clamped at the upstream point are included. The image forming apparatus according to one item. The first position is a position where the position of the sheet leading edge in the sub-scanning direction exists between the upstream point and the downstream point, and the second position is a position where the sheet leading position is the downstream side. The third position is the position of the trailing edge of the sheet in the sub-scanning direction between the upstream point and the downstream point. Is a position to
The arrival of the sheet conveyance position at the formation position corresponding to the first position and the second position is detected based on the position of the leading edge of the sheet, and the sheet conveyance position corresponds to the third position. The image forming apparatus according to claim 6, wherein the arrival of the forming position is detected based on a position of the rear end of the sheet. The corrugated structure that sandwiches the sheet in a state in which the sheet is deformed into a waveform in the main scanning direction is disposed at at least one of the two points. Image forming apparatus. In the sub-scanning direction, a structure for sandwiching the sheet is disposed at two points between which the image forming position by the recording head is sandwiched, and an upstream point of the two points in the sub-scanning direction and the image forming position Between, further, a corrugated structure is provided that sandwiches the sheet in a state where the sheet is deformed into a waveform in the main scanning direction,
The plurality of forming positions include a first position where the sheet is clamped at the upstream point of the two points, but is not clamped at the downstream point, and the sheet is clamped at both of the two points. Two positions, a third position where the sheet is clamped at the downstream point, but not at the upstream point, and the sheet is clamped in the corrugated structure; and the sheet is the downstream point Two or more positions including the third position and the fourth position among the fourth positions that are not sandwiched at the upstream point and are not sandwiched by the corrugated structure. The image forming apparatus according to claim 1, wherein the image forming apparatus is included. The first position is a position where the position of the sheet leading edge in the sub-scanning direction exists between the upstream point and the downstream point, and the second position is a position where the sheet leading position is the downstream side. The third position is a position where the sheet trailing edge in the sub-scanning direction is between the upstream point and the clamping point by the corrugated structure. And the fourth position is a position where the position of the rear end of the seat exists between the clamping point by the corrugated structure and the downstream side point,
That the transport position of the sheet has reached the position corresponding to the first position and the second position is detected based on the position of the leading edge of the sheet, and the transport position of the sheet is the third position and the fourth position. The image forming apparatus according to claim 9, wherein arrival at a position corresponding to the position is detected based on a position of the trailing edge of the sheet. An image forming apparatus,
A recording head for ejecting ink droplets;
A transport unit that reciprocates the recording head along a main scanning direction by transporting the recording head;
A control unit that forms an image on a sheet conveyed from upstream in the sub-scanning direction by controlling the recording head and the conveyance unit;
A storage unit for storing image data representing a test pattern image for adjusting the ejection operation of ink droplets;
With
The image data stored in the storage unit is image data having a width in the main scanning direction corresponding to a maximum size sheet on which the image forming apparatus can form an image,
The control unit converts the image data read from the storage unit into data for printing corresponding to the width of the sheet forming the test pattern image, and transports the recording head to the transport unit, An image forming apparatus, wherein the test pattern image is formed on the sheet by causing the recording head to perform an ink droplet ejection operation based on printing data.