JP2017124555A - Pattern, recording position deciding device, image formation device, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pattern for deciding recording position of an image with less amount of ink usage.SOLUTION: A pattern 600 is formed on a sheet material 150 for an image formation device 100 to decide recording position of an image. There are provided two straight line portions 601 which are vertical to a scanning direction of the light that is emitted for the image formation device to receive the light reflected from the pattern, and a reflection light reading part 602 which is arranged between the two straight line portions, having a dimension for housing at least the entire of the light. The image formation device decides position of the pattern based on the reflection light when the light is scanned in an order of the first straight line portion, the reflection light reading part and a second straight line portion. The pattern is used for deciding recording position of the image based on the position.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pattern, a recording position determining apparatus, an image forming apparatus, and a program.

  2. Description of the Related Art An image forming apparatus that forms an image by ejecting droplets of ink or the like onto a sheet material such as paper is known (hereinafter referred to as a liquid ejection type image forming apparatus). Liquid discharge type image forming apparatuses can be roughly classified into serial type and line head type. In the serial image forming apparatus, the recording head reciprocates at right angles to the paper feeding direction (in the main scanning direction) while repeating paper feeding to form an image on the entire paper. In the line head type image forming apparatus, the nozzles are arranged to be approximately the same length as the maximum paper width, and the nozzles in the line head discharge the liquid droplets when the paper is sent and the liquid droplets are discharged. Form.

  However, in the serial type image forming apparatus, when one ruled line is formed in both the forward and backward directions, the ruled line is likely to be displaced in the forward and backward paths due to the deviation of the landing positions of the droplets. It has been known. Also, in a line head type image forming apparatus, a line parallel to the paper feed direction is likely to appear if there is a nozzle that steadily shifts the landing position of a droplet due to nozzle processing accuracy or mounting error. Are known.

  For this reason, an adjustment unit that adjusts an image recording position (droplet landing position) may be mounted in a liquid ejection type image forming apparatus. The adjusting means mainly has a light emitting means for irradiating the sheet material with light and a light receiving means for receiving the reflected light from the sheet material. When spot light irradiated by a light emitting element (for example, LED) scans a pattern for detecting an image recording position (hereinafter referred to as a test pattern), reflected light corresponding to the density of the spot light scanning position is reflected by the light receiving element. Detected. When a test pattern is formed on a sheet material that easily reflects light, such as white, the spot light is relatively scanned when the test pattern is scanned than when the spot light is scanned over a plain area other than the test pattern. Largely absorbed.

  If the intensity of the reflected light received by the light receiving element is expressed by the magnitude of the voltage, the voltage when the spot light is superimposed on the test pattern is much lower than the voltage when the plain portion is scanned. The position of the edge of the test pattern can be determined by detecting the position where the image forming apparatus or the like has a sudden voltage drop.

  Here, when the diameter of the spot light is d and the line width of one line of the test pattern is W, it is generally preferable that the diameter of the spot light d <the line width W of the test pattern. As a result, a wide range in which the voltage decreases is ensured, so that the position of the edge of the test pattern can be determined by a relatively simple calculation.

  However, if the diameter d of the spot light is smaller than the line width W of the test pattern, there is a disadvantage that the amount of ink used increases. Therefore, it is considered to form a test pattern having a relationship of the diameter d of the spot light> the line width W (see, for example, Patent Document 1). Patent Document 1 discloses an image in which a test pattern in which the diameter d of the spot light SP is larger than the line width W is formed, and the center position of the line is detected by calculating the inclination of the intensity data in the vicinity of the minimum received light amount. A forming apparatus is disclosed.

  However, as disclosed in Patent Document 1, in the test pattern having the relationship of “spot light diameter d> line width W”, the amount of ink used is reduced, but the calculation processing for determining the line position is complicated. There was a problem of becoming.

  In view of the above problems, an object of the present invention is to provide a pattern for determining an image recording position with a small amount of ink used.

  The present invention relates to a pattern formed on a sheet material for an image forming apparatus to determine an image recording position, and a scanning direction of light emitted for the image forming apparatus to receive reflected light from the pattern On the other hand, the image forming apparatus includes two vertical linear portions and a reflected light reading unit that is disposed between the two linear portions and has a size that accommodates at least the entire light. The position of the pattern is determined based on the reflected light when the light is scanned in the order of the first linear portion, the reflected light reading unit, and the second linear portion, and an image is obtained based on the position. A pattern for determining the recording position is provided.

  A pattern for determining the recording position of an image can be provided with a small amount of ink used.

It is an example of the figure explaining an example of a test pattern. 1 is an example of a schematic perspective view of a serial type image forming apparatus. It is an example of the figure explaining the operation | movement of a carriage in detail. 2 is an example of a block diagram of a control unit of the image forming apparatus. FIG. It is an example of the figure which shows typically the structure for a droplet position shift sensor to detect the line center position of a test pattern. 2 is an example of a functional block diagram of an image forming apparatus regarding correction of landing position deviation. FIG. It is an example of the figure explaining the outline of determination of the test pattern and line position shown for the comparison. It is an example of the figure explaining the outline of determination of the test pattern and line position of this embodiment. It is an example of the figure which illustrates the shape of a test pattern typically. It is an example of the figure explaining the effect that the discharge speed of ink is the minimum. It is an example of the figure explaining the determination method of an edge position. It is a figure which shows another example of a shape of a test pattern. It is a flowchart figure which shows an example of the procedure in which a correction process execution part correct | amends a droplet discharge timing. It is an example of the functional block diagram of the correction process execution part which can adjust the length L of an edge reading part. FIG. 2 is an example of a diagram schematically illustrating a head arrangement and a test pattern of a line type image forming apparatus. 1 is an example of a diagram schematically illustrating an image forming system having an image forming apparatus and a server.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is an example of a diagram for explaining an example of a test pattern 600 of the present embodiment. In the test pattern 600 of the present embodiment, a conventional test pattern which is a lump is divided into two parts (a reflected light reading unit 602 and an edge reading unit 601) according to functions. The reflected light reading unit 602 is a part for the image forming apparatus to obtain a stable voltage drop, and the edge reading unit 601 is a part for accurately detecting the edge position.

FIG. 1A shows the shape of the test pattern 600. This test pattern 600 shows one line of the conventional test pattern.
A. Reflected light reading unit 602
The reflected light reading unit 602 is set such that the length H in the main scanning direction and the width W in the sub scanning direction can accommodate the entire spot light SP. That is, the length H in the main scanning direction and the width W in the sub scanning direction are approximately the same as or slightly larger than the diameter d.
B. Edge reading unit 601
The edge reading unit 601 has a length L in the main scanning direction that is about the same as a length NL of a nozzle row of a recording head described later, and a width M in the sub-scanning direction is a minimum printable width.

  FIG. 1B shows a test pattern 600 and a spot light SP that scans the test pattern 600. Since the spot light SP scans the reflected light reading unit 602, “the diameter d of the spot light SP ≦ the width of the test pattern (W + 2M)”, and the intensity of the reflected light is sufficiently lowered to calculate the edge by simple calculation. can get. Since the reflected light reading unit 602 has only a length H and a width W that are approximately the same as the diameter d of the spot light SP, the amount of ink used can be reduced.

  Further, since the length L of the edge reading unit 601 is approximately the same as the nozzle row of the recording head, the ink ejection speed is minimized as described later. As a result, the image forming apparatus can perform discharge position adjustment control that has been conventionally performed. Further, since the width M of the edge reading unit 601 is the minimum printable width, the amount of ink used can be reduced.

<Terminology>
The image forming apparatus according to the present embodiment determines the recording position of the image by detecting the line position (line center position described later) of the test pattern 600. The image recording position is the landing of an ink droplet at a target position, and specifically the landing position of an ink droplet. The landing position of the ink droplet is determined by the landing position deviation correction, and the landing position deviation correction is performed by correcting, adjusting, or controlling the droplet discharge timing.

  The test pattern is a pattern having a shape suitable for determining the recording position of the image, and the word “test” is not necessary. In this embodiment, for convenience of explanation, it is called by the term test pattern.

  In the present embodiment, the length of the test pattern 600 refers to the length in the sub-scanning direction, and the width of the test pattern 600 refers to the length in the main scanning direction.

<Configuration example of image forming apparatus>
FIG. 2 shows an example of a schematic perspective view of the serial type image forming apparatus 100. The image forming apparatus 100 is supported by the main body frame 70. A guide rod 1 and a sub guide 2 are stretched in the longitudinal direction of the image forming apparatus 100, and a carriage 5 is held on the guide rod 1 and the sub guide 2 so as to be reciprocally movable in the arrow A direction (main scanning direction). Yes.

  In the main scanning direction, an endless belt-like timing belt 9 is stretched around a driving pulley 7 and a pressure roller 15, and a part of the timing belt 9 is fixed to the carriage 5. Further, the drive pulley 7 is driven to rotate by the main scanning motor 8, whereby the timing belt 9 moves in the main scanning direction, and the carriage 5 also reciprocates in conjunction with it. The timing belt 9 is tensioned by a pressure roller 15, and the timing belt 9 can drive the carriage 5 without sagging.

  The image forming apparatus 100 also includes a cartridge 43 that supplies ink and a maintenance mechanism 26 that maintains and cleans the recording head.

  The sheet material 150 is intermittently conveyed in the arrow B direction (sub-scanning direction) by a roller or the like on the platen 40 below the carriage 5. The sheet material 150 may be a medium to which droplets can adhere, such as plain paper such as paper, glossy paper, film, and electronic substrate. The carriage 5 moves in the main scanning direction for each conveyance position of the sheet material 150, and a recording head mounted on the carriage 5 discharges droplets. When the discharge is finished, the sheet material 150 is conveyed again, and the carriage 5 moves in the main scanning direction to discharge the droplets. By repeating this, an image is formed on the entire surface of the sheet material 150.

  FIG. 3 is an example of a diagram for explaining the operation of the carriage 5 in more detail. The guide rod 1 and the sub guide 2 are spanned between the left side plate 3 and the right side plate 4, and the carriage 5 holds the guide rod 1 and the sub guide 2 slidably by the bearing 12 and the sub guide receiving portion 11. , And can be moved in the directions of arrows X1 and X2 (main scanning direction).

  The carriage 5 is equipped with recording heads 21 and 22 that discharge black (K) droplets, and recording heads 23 and 24 that discharge inks of cyan (C), magenta (M), and yellow (Y). ing. The recording head 21 is arranged because black is often used, and can be omitted.

  As the recording heads 21 to 24, a piezoelectric type, a thermal type, an electrostatic type, or the like can be used. Piezo-type recording heads 21 to 24 use piezoelectric elements as pressure generating means (actuator means) for pressurizing ink in the ink flow path (pressure generating chamber) to deform a diaphragm that forms the wall surface of the ink flow path. Then, the ink flow volume is changed and ink is ejected. The thermal recording heads 21 to 24 discharge ink with a pressure generated by generating ink bubbles by heating the ink in the ink flow path using a heating resistor. In the electrostatic recording heads 21 to 24, the diaphragm and the electrode forming the wall surface of the ink flow path are arranged to face each other, and the diaphragm is deformed by an electrostatic force generated between the diaphragm and the electrode. Ink is ejected by changing the volume of the ink flow path.

  The main scanning mechanism 32 that moves and scans the carriage 5 is disposed on the main scanning motor 8 disposed in one side in the main scanning direction, the drive pulley 7 that is rotationally driven by the main scanning motor 8, and the other in the main scanning direction. A pressure roller 15 and a timing belt 9 wound around the driving pulley 7 and the pressure roller 15 are provided. The pressure roller 15 is tensioned outward (in a direction away from the drive pulley 7) by a so-called tension spring.

  A part of the timing belt 9 is fixedly held by a belt holding unit 10 provided on the back side of the carriage 5, and the carriage 5 is pulled in the main scanning direction as the timing belt 9 moves endlessly.

  An encoder sheet 41 is disposed along the main scanning direction of the carriage 5, and the position of the carriage 5 in the main scanning direction is read by reading the slit of the encoder sheet 41 by the encoder sensor 42 provided on the carriage 5. Can be detected. When the carriage 5 is present in the recording area of the main scanning area, the sheet material 150 is intermittently conveyed by the paper feed mechanism in the directions indicated by arrows Y1 and Y2 (sub scanning direction) orthogonal to the main scanning direction of the carriage 5. The

  In the image forming apparatus 100 according to the present embodiment described above, the recording heads 21 to 24 are driven according to the image information while moving the carriage 5 in the main scanning direction and intermittently feeding the sheet material 150. A desired image can be formed on the sheet material 150 by ejecting the droplets.

  On one side surface of the carriage 5, a droplet position deviation sensor 30 for detecting landing position deviation (reading a test pattern) is mounted. The droplet position deviation sensor 30 reads the test pattern 600 for detecting the landing position formed on the sheet material 150 by a light receiving element having a light emitting element such as an LED and a reflective photosensor.

  Since this droplet displacement sensor 30 is for the recording head 21, another droplet displacement sensor 30 is mounted in parallel with the recording heads 22-24 in order to adjust the droplet discharge timing of the recording heads 22-24. Is preferred. Further, if the carriage 5 is equipped with a mechanism for sliding the droplet position deviation sensor 30 so as to be in parallel with the recording heads 22 to 24, the liquid in the recording heads 22 to 24 can be obtained by using one droplet position deviation sensor 30. Drop ejection timing can be adjusted. Alternatively, even when the image forming apparatus 100 sends the sheet material 150 in the reverse direction, the droplet discharge timing of the recording heads 22 to 24 can be adjusted by the single droplet position deviation sensor 30.

  FIG. 4 is an example of a block diagram of the control unit 300 of the image forming apparatus 100. The control unit 300 includes a main control unit 310 and an external I / F 311. The main control unit 310 includes a CPU 301, a ROM 302, a RAM 303, an NVRAM 304, an ASIC 305, an FPGA (Field Programmable Gate Array) 306, and the like. The CPU 301 executes a program 3021 expanded from the ROM 302 to the RAM 303 to control the entire image forming apparatus 100. In addition to the program 3021, the ROM 302 stores fixed data such as initial values and control parameters. The program 3021 controls the entire image forming apparatus 100 and corrects a landing position deviation.

  The RAM 303 is a working memory that temporarily stores programs, image data, and the like, and the NVRAM 304 is a non-volatile memory that holds data such as setting conditions while the apparatus is powered off. The ASIC 305 performs various signal processing and rearrangement on the image data, and controls various engines. The FPGA 306 processes input / output signals for controlling the entire apparatus.

  The main control unit 310 controls the entire apparatus and controls the test pattern 600 formation, the test pattern 600 detection, the landing position adjustment (correction), and the like. As will be described later, in this embodiment, the CPU 301 mainly executes the program 3021 stored in the ROM 302 to detect the line center position. However, part or all of the processing may be performed by an LSI such as the FPGA 306 or the ASIC 305.

  The external I / F 311 is an interface for connecting a communication device for communicating with other devices connected to the network, USB, IEEE1394, and the like, and sends data from the outside to the main control unit 310. The external I / F 311 outputs the data generated by the main control unit 310 to the outside. A removable storage medium 320 can be attached to the external I / F 311, and the program 3021 is distributed via a state stored in the storage medium 320 or a communication device from a server or the like that distributes the program.

  The control unit 300 includes a head drive control unit 312, a main scanning drive unit 313, a sub-scanning drive unit 314, a paper feed drive unit 315, a paper discharge drive unit 316, and a scanner control unit 317. The head drive control unit 312 controls the presence / absence of ejection of each of the recording heads 21 to 24, the droplet ejection timing and the ejection amount when ejecting. The head drive control unit 312 has an ASIC for head data generation array conversion for controlling the drive of the recording heads 21 to 24 (head driver), and based on the print data (dot data subjected to dither processing), A drive signal indicating the presence / absence of a droplet and the size of the droplet is generated and supplied to the recording heads 21 to 24. Each of the recording heads 21 to 24 has a switch for each nozzle, and the recording heads 21 to 24 have a size specified at the position of the sheet material 150 specified by the print data by being turned on / off based on the drive signal. Land the droplet. The head driver of the head drive control unit 312 may be provided on the recording heads 21 to 24 side, or the head drive control unit 312 and the recording heads 21 to 24 may be integrated. The illustrated configuration is an example.

A main scanning drive unit (motor driver) 313 drives a main scanning motor 8 that moves and scans the carriage 5. The main controller 310 is connected to the encoder sensor 42 that detects the carriage position described above, and the main controller 310 detects the position of the carriage 5 in the main scanning direction based on the output signal. Then, the carriage 5 is reciprocated in the main scanning direction by drivingly controlling the main scanning motor 8 via the main scanning driving unit 313.
A sub-scanning driving unit (motor driver) 314 drives a sub-scanning motor 132 for feeding paper. An output signal (pulse) from the rotary encoder sensor 131 that detects the amount of movement in the sub-scanning direction is input to the main control unit 310, and the main control unit 310 detects the paper feed amount based on this output signal, By driving and controlling the sub-scanning motor 132 through the scanning drive unit 314, the sheet material 150 is fed through the conveyance roller.

  The paper feed driving unit 315 drives a paper feed motor 133 that feeds the sheet material 150 from the paper feed tray. The paper discharge drive unit 316 drives a paper discharge motor 134 that drives a roller for discharging the printed sheet material 150 onto the platen. The paper discharge drive unit 316 may be substituted by the sub-scanning drive unit 314.

  The scanner control unit 317 controls the image reading unit 135. The image reading unit 135 optically reads a document and generates image data.

  The main control unit 310 is connected to various keys such as a numeric keypad and a print start key and various displays and an operation / display unit 136 including a touch panel. The main control unit 310 receives a key input operated by the user via the operation / display unit 136, displays a menu, and the like.

  In addition, a recovery system drive unit for driving a maintenance recovery motor that drives the maintenance mechanism 26, a solenoid drive unit (driver) for driving various solenoids (SOL), a clutch drive unit for driving electromagnetic cracks, etc. You may have. The main control unit 310 is connected to sensors used in the present embodiment, and various sensors other than those illustrated may be connected.

  The main control unit 310 performs a process of forming the test pattern 600 on the sheet material, and performs light emission drive control for causing the light emitting element of the droplet displacement sensor 30 mounted on the carriage 5 to emit light with respect to the formed test pattern 600. . Then, the output signal of the light receiving element is acquired, the reflected light of the test pattern 600 is electrically read, the landing position deviation amount is detected from the read result, and the droplets of the recording heads 21 to 24 are further detected based on the landing position deviation amount. Control is performed to correct the discharge timing so that the landing position deviation is eliminated.

<Configuration for correction of landing position deviation>
FIG. 5 is an example of a diagram schematically illustrating a configuration for the droplet position deviation sensor 30 to detect the line center position of the test pattern 600. FIG. 5 is a view of the recording head 21 and the droplet displacement sensor 30 of FIG. 3 as viewed from the right side plate 4.

  Note that the drive circuit 513, the smoothing circuit 512, the light emission control unit 511, the photoelectric conversion circuit 521, the low-pass filter circuit 522, and the A / D conversion circuit 523 are mounted on the main control unit 310 or the control unit 300.

  The droplet position deviation sensor 30 includes a light emitting element 402 and a light receiving element 403 arranged in a direction orthogonal to the main scanning direction. The arrangement of the light emitting element 402 and the light receiving element 403 may be reversed. The light emitting element 402 projects spot light SP, which will be described later, onto the test pattern 600, and the light receiving element 403 receives light reflected on the sheet material 150, reflected light from the platen 40, other scattered light, and the like. The light emitting element 402 and the light receiving element 403 are fixed to the inside of the housing, and the surface of the droplet position deviation sensor 30 facing the platen 40 is shielded from the outside by a lens 405. Thus, the droplet position deviation sensor 30 is packaged and can be distributed alone.

In the droplet position deviation sensor 30, the light emitting element 402 and the light receiving element 403 are disposed in a direction orthogonal to the scanning direction of the carriage 5 (arranged in parallel to the sub scanning direction). Thereby, the influence on the detection result by the movement speed fluctuation | variation of the carriage 5 can be reduced.
The light emitting element 402 is, for example, an LED, and the peak emission wavelength is 563 nano [m] corresponding to green. In addition, the light receiving element 403 has a peak light receiving sensitivity wavelength of 560 nanometers according to the light emitting element. The reason for adopting such a wavelength is that the ink color of the test pattern 600 is mainly K, M, and C, but the wavelength at which both the reflection intensities of the M and C inks are small (easy to be absorbed) is 560 nano [ m] for the periphery. For this reason, when the ink color is other than the above (K, M, C), the wavelength of the light emitting element 402 may be designed if necessary.

  Further, the diameter of the spot light SP formed by the light emitting element 402 is in the order of mm in order to use an inexpensive lens without using a highly accurate lens. The diameter of the spot light SP is related to the detection accuracy of the edge of the test pattern 600, but the line center position can be detected with sufficiently high accuracy in the mm order if the method of obtaining the line center position of the present embodiment is used. However, the diameter of the spot light SP can be made smaller.

  The CPU 301 starts the landing position deviation correction at a predetermined timing. This timing is, for example, a timing at which the user instructs correction of landing position deviation from the operation / display unit 136, and since the light emitting element 402 emits light before ink ejection and the intensity of reflected light at that time is a predetermined value or less, a specific sheet The timing at which the CPU 301 determines that the material 150 is the material, the temperature and humidity at the time of the last landing position deviation correction are stored, and the timing at which it is determined that either the temperature or humidity has deviated by more than a threshold value, or periodically ( Daily, weekly, monthly, etc.).

  The formation of the test pattern 600 will be described. The CPU 301 instructs the main scanning drive unit 313 to reciprocate the carriage 5, and instructs the head drive control unit 312 to discharge droplets using a predetermined test pattern 600 as print data. The main scanning drive unit 313 reciprocates the carriage 5 with respect to the sheet material 150 in the main scanning direction, and the head drive control unit 312 ejects droplets from the recording head 21 to form the test pattern 600.

  Further, the CPU 301 performs control for reading the test pattern 600 formed on the sheet material 150 by the droplet position deviation sensor 30. Specifically, the CPU 301 sets a PWM value for driving the light emitting element 402 of the droplet position deviation sensor 30 in the light emission control unit 511, and the output of the light emission control unit 511 is smoothed by the smoothing circuit 512 and driven. Is provided to circuit 513. The drive circuit 513 drives the light emitting element 402 to emit light, and the test pattern 600 of the sheet material 150 is irradiated with the spot light SP from the light emitting element 402.

  By irradiating the test pattern 600 on the sheet material with the spot light SP from the light emitting element 402, the reflected light reflected from the test pattern 600 enters the light receiving element 403. The light receiving element 403 outputs an intensity signal of the reflected light to the photoelectric conversion circuit 521. Specifically, the photoelectric conversion circuit 521 photoelectrically converts the intensity signal and outputs this photoelectric conversion signal (sensor detection voltage) to the low-pass filter circuit 522. The low-pass filter circuit 522 outputs a photoelectric conversion signal to the A / D conversion circuit 523 after removing high-frequency noise. The A / D conversion circuit 523 A / D converts the photoelectric conversion signal and outputs the signal to a signal processing circuit (FPGA) 306. A signal processing circuit (FPGA) 306 stores detection voltage data, which is a digital value of the detection voltage subjected to A / D conversion, in the RAM 303.

  In the illustrated configuration, the drive circuit 513, the smoothing circuit 512, the light emission control unit 511, the photoelectric conversion circuit 521, the low-pass filter circuit 522, and the A / D conversion circuit 523 are outside the droplet displacement sensor 30. A part or all of these may be arranged in the droplet displacement sensor 30.

<Functions related to correction of landing position deviation>
FIG. 6 shows an example of a functional block diagram of the image forming apparatus 100 regarding correction of landing position deviation. The correction processing execution unit 60 includes a test pattern printing unit 61, a position deviation sensor control unit 62, and a landing position deviation correction unit 63. In the test pattern printing unit 61 and the landing position deviation correction unit 63, any one of the components shown in FIGS. 4 and 5 is operated by a command from the CPU 301 according to the program 3021 expanded from the ROM 302 to the RAM 303. This is a function realized or a provided means.

  The correction processing execution unit 60 includes a test pattern data storage unit 68 and a detection voltage data storage unit 69 constructed by the ROM 302, the RAM 303, and the NVRAM 304 shown in FIG. The test pattern data storage unit 68 stores image data of the test pattern 600 shown in FIG. The detection voltage data storage unit 69 stores the detection voltage data of the reflected light from the test pattern 600 acquired by the light receiving element 403 described with reference to FIG.

  The test pattern printing unit 61 is realized by the CPU 301 and the head drive control unit 312 shown in FIGS. 4 and 5, reads the test pattern data stored in the test pattern data storage unit 68, and forms it on the sheet material 150.

  The misalignment sensor control unit 62 is realized by the CPU 301 shown in FIG. 5 and the like, and performs control related to light emission of the light emitting element 402 and control related to light reception of the light receiving element 403 according to the procedure shown in FIG. The positional deviation sensor control unit 62 stores the acquired detection voltage data in the detection voltage data storage unit 69.

  The landing position deviation correction unit 63 reads the detection voltage data stored in the detection voltage data storage unit 69, corrects the landing position deviation, and sets it in the head drive control unit 312. That is, the landing position deviation correction unit 63 determines the position of the test pattern 600 (the edge positions of the two edge reading units 601). Thereby, a line center position is known. Since the appropriate distance between the line center position of one test pattern 600 and the line center position of the adjacent test pattern 600 is known, the amount of landing position deviation can be calculated.

  Then, a droplet discharge timing correction value when driving the recording head 21 so as to eliminate the landing position deviation is calculated, and this droplet discharge timing correction value is set in the head drive control unit 312. Accordingly, when the recording head 21 is driven, the head driving control unit 312 corrects the droplet discharge timing based on the correction value and then drives the recording head 21, thereby reducing the landing position deviation of the droplet. be able to. That is, it is possible to correct the droplet discharge timing, determine the landing position of the ink droplet, and further determine the recording position of the image.

<Determination of line position>
<< Test pattern comparison example >>
FIG. 7 is an example for explaining an outline of determination of the test pattern and the line position shown for comparison. Numbers I to V in FIG. 7A indicate the passage of time, and the lower the spot light SP, the longer the passage of time. In FIG. 7A, the spot light SP seems to cross the test pattern 600 while being fed, because this is illustrated so that the spot light SP does not overlap. Actually, the sheet material 150 is stationary.
Time I: Spot light SP and test pattern 600 are not superimposed.
Time II: Half of the spot light SP is superimposed on the test pattern 600. At this moment, the reduction rate of the reflected light becomes the largest (the overlapped area changes most positively in unit time).
Time III: The entire spot light SP is superimposed on the test pattern 600. At this moment, the intensity of the reflected light becomes the smallest.
Time IV: Half of the spot light SP is superimposed on the test pattern 600. At this moment, the increase rate of the reflected light becomes the largest (the overlapping area changes most negatively per unit time).
Time V: Spot light SP passes through test pattern 600, and spot light SP and test pattern 600 are not superimposed.

  It is time II and IV that the center of gravity of the spot light SP coincides with the edge position of the line of the test pattern 600. Therefore, if the spot light SP and the line can be identified by the analysis of the detected voltage data that the relationship between the times II and IV is established, the edge position of the line can be accurately determined.

  7B shows an example of the detection voltage of the light receiving element, FIG. 7C shows an example of the absorption area (the overlapping area of the spot light SP and the test pattern 600), and FIG. 7D shows the example of FIG. An example of the increase rate of the absorption area obtained by differentiating the absorption area of each is shown. By differentiating, data indicating the magnitude of the gradient of the detection voltage is obtained. Note that even if the output waveform in FIG. 7B is differentiated, the same information as in FIG. 7D can be obtained. Further, the absorption area is calculated from the detection voltage, for example, but does not need to be an absolute value. Therefore, the absorption area in FIG. 7C is obtained by subtracting the detection voltage in FIG. 7B from the predetermined value. A waveform similar to is obtained.

  As described above, the decrease rate of reflected light becomes the largest at time II (the overlapping area changes most positively in unit time), and the increase rate of the reflected light becomes largest at time IV (superimposed). Area changes most negatively per unit time). As shown in FIG. 7 (d), the point at which the increase rate changes from an increasing trend to a decreasing trend is coincident with time II, and the point at which the increase rate changes from a decreasing trend to an increasing trend is at time IV. Is consistent with

  A point that changes from an increasing tendency to a decreasing tendency or vice versa is a point where the bending direction changes in a curved line on a plane, that is, an inflection point. From the above, if the output signal indicates an inflection point, the spot light SP coincides with the edge position of the test pattern 600. Therefore, if the inflection point is detected with high accuracy, the edge position can be determined with high accuracy.

<< Test pattern and spot light SP of this embodiment >>
FIG. 8 is an example of a diagram illustrating an outline of determination of the test pattern 600 and the line position according to the present embodiment. In the description of FIG. 8A, differences from FIG. 7 will be mainly described. Details of the shape of the test pattern 600 will be described later.

  When the test pattern 600 is formed, the misalignment sensor control unit 62 moves the carriage 5 so that the spot light SP crosses the reflected light reading unit 602. That is, the spot light SP scans the test pattern 600 in the order of the first edge reading unit 601, the reflected light reading unit 602, and the second edge reading unit 601. The positions of the edge reading unit 601 and the reflected light reading unit 602 in the sheet material 150 (positions in the main scanning direction and the sub-scanning direction) are controlled. Further, the position of the droplet position deviation sensor 30 is also controlled together with the recording head 21 and the like. Therefore, the misalignment sensor control unit 62 can cause the spot light SP to scan the reflected light reading unit 602.

  As shown in FIG. 8, the spot light SP is scanned in the order of the edge reading unit 601, the reflected light reading unit 602, and the edge reading unit 601, whereby detection voltage data similar to the test pattern 600 of FIG. 7 is obtained.

  One reflected light reading unit 602 and two edge reading units 601 correspond to one line of the conventional test pattern 600. Therefore, by forming a plurality of test patterns 600, the image forming apparatus 100 can perform landing position deviation correction. As will be described later, the landing position deviation correction unit 63 specifies the edge Eg by each of the two edge reading units 601 and determines the midpoint thereof as the line center position P. The distance between the line center positions P of the two test patterns 600 is the distance LL between the two lines. The landing position deviation correction unit 63 compares the distance LL between the two lines with an appropriate distance, and determines a correction value for correcting the landing position deviation.

<Test pattern of this embodiment>
A test pattern 600 according to the present embodiment will be described with reference to FIGS. FIG. 9 is an example of a diagram schematically illustrating the shape of the test pattern. As described above, the test pattern 600 includes the reflected light reading unit 602 that reads reflected light when the spot light SP passes through substantially the center of the edge reading unit 601 in the length direction. An edge reading unit 601 for accurately reading the edge of the test pattern 600 is provided on both sides.

  The edge reading unit 601 is a straight line portion formed perpendicular to the scanning direction of the spot light SP. The reflected light reading unit 602 is disposed between the two edge reading units 601. Although the reflected light reading unit 602 and the two edge reading units 601 are macroscopically in contact (no gap), a gap may be formed between the reflected light reading unit 602 and the two edge reading units 601. For example, even if dots permeate around the landing position, a gap of 1 dot or less can be generated, but the intensity of reflected light is hardly affected. Accordingly, a minute gap that is not affected by the intensity of the reflected light may be generated.

  The length H and the width W of the reflected light reading unit 602 are approximately the same as or slightly larger than the diameter d of the spot light SP so that the entire spot light SP is accommodated. Therefore, the reflected light reading unit 602 is slightly larger than the circumscribed rectangle of the spot light SP or the circumscribed rectangle. The length H of the reflected light reading unit 602 is at least shorter than the length L of the edge reading unit 601. As a result, the amount of ink used can be reduced, and furthermore, since the detection voltage is sufficiently lowered, the inflection point can be accurately detected. Note that the reflected light reading unit 602 does not have to be rectangular as long as the entire spot light SP is contained.

  On the other hand, since it is preferable that the edge of the test pattern 600 is accurately read from the edge reading unit 601, the length L is substantially the same as the length NL of the nozzle row, and the width M is the minimum printable width. The minimum printable width is the narrowest width that can be formed as a line. The minimum printable width is determined by the volume of one droplet (picoliter) and the surface condition of the sheet material 150. Therefore, for example, it is 10 to several tens of micrometers although it cannot be generally stated.

  Since the length L of the edge reading unit 601 is substantially the same as the length NL of the nozzle row, the ink ejection speed is minimized. The effect of the minimum discharge speed will be described with reference to FIG. Further, since the width M of the edge reading unit 601 is the minimum printable width, the amount of ink used can also be reduced here.

  Therefore, the test pattern 600 of the present embodiment can reduce the amount of ink used at the time of formation, and can further reduce the line edge Eg, the line center position P, and the line of the test pattern 600 without requiring complicated calculation processing. Allows determination of the distance LL between two lines.

  The effect of the minimum ink ejection speed will be described with reference to FIG. FIG. 10A is an example for explaining the relationship between the number of drive nozzles and the ink ejection speed S. FIG. The number of drive nozzles means the number of nozzles that simultaneously eject ink droplets in the same print head, that is, the number of nozzles of the print head that is driven and controlled simultaneously. For example, when a plurality of recording heads are mounted on the same base, the ink droplet ejection speed varies depending on the number of nozzles of the piezo elements that are driven simultaneously. The ink ejection speed S is the speed at which ink reaches the sheet material 150 from the nozzle row, and is an observed value.

  As shown in FIG. 10A, the droplet discharge speed (Vj) varies greatly depending on the number of drive nozzles. There are structural and electrical reasons for the fluctuation. As a structural factor, an example in the case of a piezo (piezoelectric element) actuator type recording head is given.

  In this method, a drive waveform is applied to the piezo to change the piezoelectric element, thereby pressurizing ink in the pressurized liquid chamber and ejecting ink droplets from the nozzle.

  At this time, the pressure applied to the ink in the pressurized liquid chamber changes depending on the number of drive nozzles, and the droplet velocity changes. Even in the case of a thermal ink jet recording apparatus, the same phenomenon occurs because bubbles are generated in the pressurized liquid chamber to pressurize the ink.

  As an electrical factor, the recording head behaves such that the capacitance and inductance change depending on the number of drive nozzles and the wiring length. This change causes a change in the waveform output from the drive waveform generation circuit, which affects the ink droplet ejection speed (Vj).

  Depending on the number of drive nozzles, which factor is dominant is different. In the vicinity of the number of driving nozzles n1, where the number of driving nozzles is small, the influence of structural factors is large. When the number of driving nozzles exceeds n2, the influence of electrical factors is large.

Variations in fluctuations in the droplet ejection speed (Vj) due to electrical factors can be reduced relatively easily by adjusting circuit constants and the like. On the other hand, as shown in FIG. The distance is constant and is always constant during image formation. In the serial type image forming apparatus 100, the test pattern 600 is formed while the carriage 5 moves. For this reason, when the number of drive nozzles changes, the ejection speed S changes and the ink landing position shifts.

  The change in the ejection speed S also occurs when image data is formed during normal printing other than the test pattern 600 (when executing a print job transmitted from a PC (Personal Computer) instead of the test pattern). However, the main control unit 310 and the head drive control unit 312 perform a process of correcting the ejection timing in accordance with the number of drive nozzles so that the landing position does not shift even if the number of drive nozzles increases or decreases ( This control is called discharge position adjustment control).

  As shown in FIG. 10A, the discharge speed S is more stable and the electric control is possible when the number of drive nozzles is larger. Therefore, the adjustment of the discharge position can easily improve the image quality by adopting a control that advances or delays the discharge timing based on the maximum number of drive nozzles. On the other hand, it is difficult to adopt the discharge speed S when the number of drive nozzles is small (n1 or less) as a reference because it is difficult to control. Therefore, conventionally, discharge position adjustment control is performed based on the ink discharge speed S when the number of drive nozzles is the maximum.

  Since the test pattern 600 is used for adjusting the reference recording position, it is preferable that the length L of the edge reading unit 601 of the test pattern 600 is substantially the same as the length NL of the nozzle row.

  Further, since the length L of the edge reading unit 601 is longer than the diameter d of the spot light SP, the edge position can be specified even if the scanning position of the spot light SP is slightly different.

  From the above, in the test pattern 600 of this embodiment, the length H and the width W of the reflected light reading unit 602 are approximately the same as the diameter d of the spot light SP, and the length L of the edge reading unit 601 is the length of the nozzle row. It is effective that the width M is almost the same as the length NL and the minimum printable width.

  Further, since the adjustment control of the ejection position may be performed based on the length L of the arbitrary edge reading unit 601, the length L of the edge reading unit 601 may not be the same as the length NL of the nozzle row. Good. The length L of the edge reading unit 601 may be longer or shorter than the length NL of the nozzle row. However, the diameter is preferably equal to or larger than the diameter d of the spot light SP.

<Determination method of edge position>
FIG. 11 is an example of a diagram illustrating a method for determining an edge position. 11A shows a schematic diagram of the detection voltage, and FIG. 11B shows an enlarged view of the detection voltage. The approximate value of the inflection point can be obtained experimentally by the landing position deviation correction unit 63 or the developer. As described above, for example, the inflection point is a position where the detected voltage V and the absorption area are differentiated and the slope is closest to zero.

  An upper limit threshold value Vru and a lower limit threshold value Vrd of the detection voltage V are determined in advance so that this inflection point is included. The CPU 301 calibrates the output of the light emitting element 402 and the sensitivity of the light receiving element 403 so that the detection voltage V becomes substantially the same constant value (4 [V] described later) in an area where the test pattern 600 is not present. By correcting the drawing density of the present embodiment, the maximum value of the detection voltage V can be made substantially the same constant value, so that an inflection point is included between the upper limit threshold value Vru and the lower limit threshold value Vrd.

  The landing position deviation correction unit 63 searches the falling portion of the detection voltage V in the direction indicated by the arrow Q1, and stores the point where the detection voltage V is equal to or lower than the lower limit threshold Vrd as the point P2. Next, the point P2 is searched in the direction indicated by the arrow Q2, and the point where the detected voltage V exceeds the upper limit threshold value Vru is stored as the point P1.

  Then, a regression line L1 is calculated using a plurality of detection voltage data between the points P1 and P2, and an intersection point between the regression line L1 and the upper and lower threshold intermediate value Vc is calculated as an intersection point C1.

  Similarly, the landing position deviation correction unit 63 searches the rising portion of the detection voltage V in the direction indicated by the arrow Q3, and stores the point where the detection voltage V is equal to or higher than the upper threshold value Vru as a point P4. Next, the point P4 is searched in the direction indicated by the arrow Q4, and the point where the detected voltage V is equal to or lower than the lower limit threshold value Vrd is stored as the point P3.

  Then, a regression line L2 is calculated using a plurality of detected voltage data between the points P3 and P4, and an intersection point between the regression line L2 and the intermediate value Vc of the upper and lower thresholds is calculated as an intersection point C2. Since the intersection point C1 and the intersection point C2 are edge positions of one line, the center of the intersection points C1 and C2 is the line center position P.

  Thereafter, the landing position deviation correction unit 63 obtains the line center positions of the plurality of lines, and calculates the difference between the appropriate distance between the two lines of the test pattern 600 and the distance between the line centers. Since this difference is a deviation of the actual line position with respect to the appropriate line position, it becomes a landing position deviation amount. The landing position deviation correction unit 63 calculates a correction value for correcting the timing of ejecting droplets from the recording head 21 (droplet ejection timing) based on the calculated landing position deviation amount, and the correction value is used as a head drive control unit. 312 is set. As a result, the head drive control unit 312 drives the recording head 21 at the corrected droplet discharge timing, so that landing position deviation is reduced.

<Other examples of test patterns>
FIG. 12 shows another example of the shape of the test pattern 600. In FIG. 12A, the reflected light reading unit 602 is formed on the uppermost part of the edge reading unit 601 (upstream in the sub-scanning direction). In FIG. 12B, the reflected light reading unit 602 is formed at the lowermost part of the edge reading unit 601 (downstream in the sub-scanning direction). As described above, the reflected light reading unit 602 only needs to be between the two edge reading units 601 and may not be in the center or near the center.

  In FIG. 12C, the length of the edge reading unit 601 is the same as that of the reflected light reading unit 602. With such a shape, the amount of ink used can be minimized. On the other hand, since the ink ejection speed is not the lowest, the number of drive nozzles is larger or smaller than the number of nozzles of the length of the edge reading unit 601 when image data is formed during normal printing. Accordingly, the main controller 310 and the head drive controller 312 control the landing position.

<Operation procedure>
FIG. 13A is a flowchart illustrating an example of a procedure in which the correction processing execution unit 60 corrects the droplet discharge timing.

  First, the CPU 301 instructs the main control unit 310 to start landing position deviation correction. In response to this instruction, the main control unit 310 drives the sub-scanning motor 132 via the sub-scanning driving unit 314 to convey the sheet material 150 to just below the recording head 21 (S1).

  Next, the main control unit 310 drives the main scanning motor 8 via the main scanning drive unit 313 to move the carriage 5 onto the sheet material 150 and receive light from the light emitting element at a specific location on the sheet material 150. The element is calibrated (S2).

  FIG. 13B is an example of a flowchart for explaining the process of S2. The calibration is a process of adjusting the light amount of the light emitting element so that the detection voltage of the light emitting element is within a desired range (for example, adjusted within a range of 4 ± 0.4 [V]).

  The CPU 301 sets a PWM value for driving the light emitting element 402 of the droplet position deviation sensor 30 in the light emission control means 511, smoothes it by the smoothing circuit 512, and then gives it to the driving circuit 513, thereby providing the driving circuit 513. Drives the light emitting element 402 to emit light (S21).

  The detected voltage data detected by the light receiving element 403 of the droplet position deviation sensor 30 is stored in the RAM 303, and the CPU 301 checks whether it has a desired voltage value (S22).

  If the desired voltage value is reached (OK at S22), the process of FIG. 13B ends. If the desired voltage value is not reached (No in S22), the CPU 301 changes the PWM value (S23) to readjust the light amount.

  Returning to FIG. 13A, the main control unit 310 moves the carriage 5 via the main scanning motor 8 by the main scanning driving unit 313 without feeding the paper while keeping the sub-scanning position of the sheet material 150. Then, the head drive control unit 312 drives the recording heads 21 to 24 using the test pattern 600 stored in the test pattern data storage unit 68 (S3). A test pattern 600 shown in FIG. 8 and the like can be formed. For example, when the correction processing execution unit 60 adjusts the magenta landing position deviation with reference to black, the black and magenta test patterns 600 are alternately formed. The same applies to other colors.

  Next, the landing position deviation correction unit 63 detects the line center position P of the test pattern 600 from the detected voltage data, and corrects the landing position deviation of the droplet (S4). That is, the landing position deviation correction unit 63 calculates the landing position deviation amount by comparing the distance LL between two adjacent lines with an appropriate distance, and calculates the correction value of the droplet discharge timing so that the landing position deviation is eliminated. And set in the head drive control unit 312.

  As described above, the image forming apparatus 100 according to the present embodiment forms the test pattern 600 including the reflected light reading unit 602 and the edge reading unit 601, thereby reducing the amount of ink used while adjusting the discharge position. Can be suppressed. Further, the position of the edge Eg of the test pattern 600 can be determined by a relatively simple calculation.

<Automatic adjustment of the length of the edge reading unit 601>
Further, the correction processing execution unit 60 may adjust the length L of the edge reading unit 601 according to the average number of drive nozzles. FIG. 14 shows an example of a functional block diagram of the correction processing execution unit 60 that can adjust the length L of the edge reading unit 601. The correction processing execution unit 60 of FIG. 14 has a nozzle number recording unit 64. The nozzle number recording unit 64 records the number of drive nozzles that are simultaneously driven during normal printing. For example, the number of drive nozzles that are simultaneously driven every time the recording head 21 ejects ink or periodically (such as once every few seconds) is recorded.

  Then, the nozzle number recording unit 64 calculates an average value of the number of drive nozzles recorded at the timing of adjusting the droplet discharge timing. Since the nozzle number recording unit 64 notifies the test pattern printing unit 61 of the average value, the test pattern printing unit 61 sets the length occupied by the number of nozzles of this average value to the length of the edge reading unit 601.

  For example, the average number of drive nozzles may be stable for most documents with letters and numbers. In such a case, if the length L of the edge reading unit 601 at the time of landing position deviation correction is the same as the length of the average number of drive nozzles, the landing position deviation will occur even if the discharge position adjustment control is not performed. It may not occur or may be acceptable.

  Therefore, since the number of drive nozzles used for actual printing matches the number of drive nozzles when the test pattern 600 is formed, it is possible to adjust the droplet discharge timing to be optimal for actual printing.

<In the case of a line type image forming apparatus>
In the present exemplary embodiment, the serial type image forming apparatus 100 illustrated in FIG. 3 and the like has been described as an example, but the line type image forming apparatus 100 can also correct the landing position deviation amount by the same method. The line type image forming apparatus 100 will be briefly described.

  FIG. 15 is an example of a diagram schematically illustrating the head arrangement and the test pattern 600 of the line type image forming apparatus 100. The head fixing bracket 160 is fixed so as to be spanned from end to end in the main scanning direction orthogonal to the sheet material conveyance direction. In the head fixing bracket 160, recording heads 180 of KCMY ink are arranged from the upstream side over the entire area in the main scanning direction. The recording heads 180 for each color are arranged in a staggered manner so that the ends overlap. By doing so, droplets with sufficient resolution are ejected even at the end of the recording head 180, so that it is not necessary to dispose one recording head 180 over the entire region in the main scanning direction, and an increase in cost can be suppressed. Note that one recording head 180 may be arranged in the entire region in the main scanning direction for each ink color, or the overlapping region in the main scanning direction of the recording head 180 for each color may be made longer.

  A sensor fixing bracket 170 is fixed downstream from the head fixing bracket 160 so as to be spanned from end to end in the main scanning direction orthogonal to the sheet material conveyance direction. In the sensor fixing bracket 170, the droplet position deviation sensors 30 are arranged by the number of heads. That is, one droplet position deviation sensor 30 is disposed so as to at least partially overlap one recording head 180 in the main scanning direction. One droplet position deviation sensor 30 has a pair of light emitting element 402 and light receiving element 403. The light emitting element 402 and the light receiving element 403 are arranged in parallel substantially in parallel with the main scanning direction.

  The image forming apparatus 100 having such a configuration forms the edge reading unit 601 of the test pattern 600 so as to be parallel to the main scanning direction. When correcting landing position deviation of droplets of other colors based on K, the image forming apparatus 100 forms a K line and an M line, a K line and a C line, and a K line and a Y line. To do. Similarly to the serial type image forming apparatus 100, the line center position P of the CMYK test pattern 600 is detected, and the droplet discharge timing is corrected from the distance LL between the two lines.

  As described above, also in the line type image forming apparatus 100, the landing position deviation can be corrected by appropriately disposing the droplet position deviation sensor 30.

<Correction of landing position deviation by server>
The landing position deviation may be corrected by the server instead of the image forming apparatus 100.
FIG. 16 is an example of a diagram schematically illustrating an image forming system 500 including the image forming apparatus 100 and the server 200. In FIG. 16, the same parts as those in FIG. The image forming apparatus and the server 200 are connected via a network 201. The network 201 is an in-house LAN, a WAN connecting the LANs, the Internet, or a combination of these.

  In the image forming system 500 as shown in FIG. 16, the image forming apparatus 100 forms the test pattern 600 and scans the test pattern 600 by the droplet position deviation sensor 30. The image forming apparatus 100 transmits detection voltage data acquired by scanning the test pattern 600 to the server 200. The server 200 analyzes the detected voltage data, calculates a correction value for landing position deviation, and transmits the calculated value to the image forming apparatus 100. Accordingly, the processing load on the image forming apparatus 100 can be reduced, and the function for calculating the correction value of the droplet discharge timing can be integrated in the server 200.

<Other application examples>
The best mode for carrying out the present invention has been described above with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the scope of the present invention. And substitutions can be added.

  For example, in the present embodiment, it has been described that ink is ejected to form an image. However, an image may be formed by ejecting metal paste or the like as ejected matter. Alternatively, an image may be formed by discharging (irradiating) visible light, ultraviolet light, infrared light, laser, or the like. In this case, for example, a sheet material 150 that reacts to heat or light is used. Further, a transparent liquid may be discharged. In this case, visible information is obtained when light in a specific wavelength region is irradiated.

  For example, the configuration examples in FIGS. 4 to 6 are divided according to main functions in order to facilitate understanding of processing by the image forming apparatus 100. The present invention is not limited by the way of dividing the processing unit or the name. The processing of the image forming apparatus 100 can be divided into more processing units according to the processing content. Moreover, it can also divide | segment so that one process unit may contain many processes.

  The test pattern printing unit 61 is an example of a pattern forming unit, the landing position deviation correction unit 63 is an example of a position determining unit, and the control unit 300 is an example of a recording position determining device.

DESCRIPTION OF SYMBOLS 21 Recording head 21-24 Nozzle row 30 Droplet position shift sensor 60 Correction process execution part 61 Test pattern printing part 62 Position shift sensor control part 63 Landing position shift correction part 64 Nozzle number recording part 68 Test pattern data storage part 69 Detection voltage Data storage unit 100 Image forming apparatus

JP 2013-99865 A

Claims (10)

A pattern formed on a sheet material in order for the image forming apparatus to determine an image recording position,
Two linear portions perpendicular to the scanning direction of the light emitted for the image forming apparatus to receive the reflected light from the pattern; and
A reflected light reading unit disposed between the two straight portions and having a size that accommodates at least the whole of the light;
The image forming apparatus determines the position of the pattern based on the reflected light when the light is scanned in the order of the first linear portion, the reflected light reading unit, and the second linear portion, A pattern for determining the recording position of an image based on the position.   The pattern according to claim 1, wherein the size of the reflected light reading unit is approximately the same as a circumscribed rectangle of the light.   3. The pattern according to claim 1, wherein a length of the two linear portions is substantially the same as a length of a nozzle row from which the image forming apparatus discharges droplets. 4.   The pattern according to claim 1 or 2, wherein a length of the two straight portions is approximately the same as a circumscribed rectangle of the light. The length of the two straight portions is
3. The pattern according to claim 1, wherein the pattern is approximately the same as a length occupied by an average number of nozzles when the image forming apparatus forms an image using a nozzle array that ejects droplets.   6. The pattern according to claim 1, wherein the width of each of the two linear portions is a minimum printable width that can be formed by the image forming apparatus.   The pattern according to claim 1, wherein the two linear portions and the reflected light reading unit are in contact with each other or have a gap of 1 dot or less. A recording position determining device that reads a pattern formed on a sheet material and determines an image recording position,
Two linear portions perpendicular to the scanning direction of the light applied to receive the reflected light from the pattern;
A pattern forming means for forming a pattern on the sheet material, the pattern having a reflected light reading unit disposed between the two linear portions and having a size that accommodates at least the entire light;
The position of the pattern is determined based on the reflected light when the light is scanned in the order of the first linear portion, the reflected light reading unit, and the second linear portion, and the position of the image is determined using the position. A recording position determining device for determining a recording position; An image forming apparatus comprising the recording position determining apparatus according to claim 8,
An image forming apparatus that forms an image on the sheet material using the recording position of the image determined by the recording position determination apparatus. A recording position determination device that determines the recording position of an image by reading a pattern formed on a sheet material,
Two linear portions perpendicular to the scanning direction of the light applied to receive the reflected light from the pattern;
A pattern forming means for forming a pattern on the sheet material, which is disposed between the two linear portions and includes a reflected light reading unit having a size that accommodates at least the entire light;
The position of the pattern is determined based on the reflected light when the light is scanned in the order of the first linear portion, the reflected light reading unit, and the second linear portion, and the position of the image is determined using the position. Position determining means for determining the recording position;
Program to function as.

Images