JP2013059958A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a printing start position when an image is formed by discharging droplets from a recording head in a horizontal direction deviates compared with the case where an image is formed by discharging droplets from the recording head in a perpendicular direction.SOLUTION: An error of a printing start position due to variation of production in apparatuses is retained as a first error, and an error of an actual impact position when the droplets receive an effect due to gravity with respect to a target impact position when the droplets do not receive the effect due to the gravity is retained as a second error. Start timing in conveying a paper is controlled in accordance with the first error and second error.

Description

  The present invention relates to an image forming apparatus.

  As an image forming apparatus such as a printer, a facsimile, a copying machine, a plotter, or a complex machine of these, for example, a liquid discharge recording type image forming apparatus using a liquid discharge head (droplet discharge head) for discharging droplets as a recording head For example, an inkjet recording device is known.

  A liquid ejection type image forming apparatus having a configuration including a recording head that transports a recording medium in a horizontal direction and ejects liquid droplets downward in the vertical direction with respect to the recording medium Or “horizontal transport printing”) and a recording head that transports the recording medium in the vertical direction and ejects liquid droplets in the horizontal direction with respect to the recording medium (this is referred to as “horizontal printing”). ("Patting method" or "vertical transport printing") is known (Patent Documents 1 and 2).

  The vertical image forming apparatus has an advantage that a compact mechanism design is possible and the influence of individual pixels on the image can be minimized because the droplet discharge direction is the gravitational direction. Has an advantage that a full front operation (FFO) that can perform all operations such as jam handling and cartridge replacement from the front of the apparatus can be adopted.

Japanese Patent No. 4186557 JP 09-254401 A

  In the above-described image forming apparatus of the horizontal printing method (vertical conveyance printing), the ejected liquid is affected by gravity and thus has an elliptical shape that is long in the vertical direction. The center position is shifted downward in the vertical direction. As a result, there is a problem that the printing start position of the paper is shifted.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to make the horizontal start printing start position the same as the vertical printing start position.

In order to solve the above problems, an image forming apparatus according to the present invention provides:
In an image forming apparatus that forms an image by ejecting liquid droplets from a recording head in a horizontal direction on a recording medium conveyed in the vertical direction.
Holding means for holding information on an error between the actual landing position when the droplet discharged from the recording head is affected by the gravity with respect to the target landing position when the droplet is not affected by gravity;
And a means for controlling the feeding timing of the recording medium in accordance with the information about the error held by the holding means.

  According to the image forming apparatus of the present invention, the horizontal printing start position can be made the same as the vertical printing start position.

FIG. 3 is a side explanatory view of a mechanism unit of the image forming apparatus according to the present invention. It is explanatory drawing which looked at FIG. 1 from the arrow A direction. FIG. 6 is an explanatory diagram of a recording head. It is block explanatory drawing of a control part. It is explanatory drawing with which it uses for description of an example of the environment which uses the image forming apparatus which concerns on this invention. FIG. 6 is an explanatory diagram for explaining a print data transfer procedure between a host and an image forming apparatus. FIG. 7 is a block diagram for explaining a print processing unit that handles print data on the printing unit side in FIG. 6. It is explanatory drawing with which it uses for description of the pixel formed by vertical printing (horizontal conveyance printing), and description of the pixel formed by horizontal printing (vertical conveyance printing). It is explanatory drawing with which it uses for description of the error of the landing position in horizontal strike (vertical conveyance printing). It is a flowchart with which it uses for description of the conveyance control in 1st Embodiment of this invention. It is a flowchart with which it uses for description of the conveyance control in 2nd Embodiment of this invention. It is a flowchart with which it uses for description of the 2nd error determination process for monochrome printing in 3rd Embodiment of this invention. It is a flowchart with which it uses for description of the 2nd error determination process for color printing in the embodiment. It is explanatory drawing with which it uses for description of 5th Embodiment of this invention. It is explanatory drawing with which it uses for description of 6th Embodiment of this invention. FIG. 2 is an explanatory diagram illustrating an example of a vertical image forming apparatus. FIG. 2 is an explanatory diagram illustrating an example of a horizontal image forming apparatus.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an image forming apparatus according to the present invention will be described with reference to FIGS. 1 is an explanatory side view of the mechanism of the image forming apparatus, and FIG. 2 is an explanatory view of FIG.

  This image forming apparatus is a serial type image forming apparatus, and has an image forming unit 2, a transport mechanism unit 5 and the like inside the apparatus main body, and can stack sheets 10 as recording media on the lower side of the apparatus main body. A paper feed tray (including a paper feed cassette and used in the meaning of a paper feed unit) 4 is provided, the paper 10 fed from the paper feed tray 4 is taken in, and the paper 10 is moved vertically by the transport mechanism unit 5 ( The image forming unit 2 discharges droplets in the horizontal direction and records a required image while intermittently transporting the sheet 10 in the direction along the vertical direction). The paper 10 is conveyed upward and discharged to a paper discharge tray 7 provided on the upper side of the apparatus main body.

  Also, when performing double-sided printing, after the printing on one side (front side) is completed, the paper 10 is taken into the reversing unit 8 from the paper discharge unit 6 and reversed while being conveyed in the reverse direction (downward) by the transport mechanism unit 5. Then, the other side (back side) is sent to the transport mechanism 5 again as a printable side, and the paper 10 is discharged to the discharge tray 7 after the other side (back side) printing is completed.

  Here, the image forming unit 2 slidably holds a carriage 23 on which a recording head 24 is mounted with a main guide member 21 and a sub guide member 22 that are horizontally mounted between the left and right side plates 101L and 101R, and a main scanning motor. 25, the moving scanning is performed in the main scanning direction via the timing belt 28 passed between the driving pulley 26 and the driven pulley 27.

  The carriage 23 has recording heads 24a and 24b composed of liquid ejection heads for ejecting ink droplets of each color of yellow (Y), magenta (M), cyan (C), and black (K). As shown, the recording head 24 is arranged in a sub-scanning direction perpendicular to the main scanning direction, and the droplet discharge direction is mounted in the horizontal direction. That is, a horizontal driving method is employed in which a nozzle surface on which nozzles for discharging droplets are formed is arranged in the vertical direction and includes a recording head 24 that discharges droplets in the horizontal direction.

  For example, as shown in FIG. 3, the recording head 24 includes two nozzle arrays Na and Nb each having a plurality of nozzles 124b that discharge a plurality of droplets, and one nozzle array Na of the recording head 24a is Yellow (Y) droplets, the other nozzle row Nb is magenta (Y) droplets, one nozzle row Na of the recording head 24b is black (K) droplets, and the other nozzle row Nb is cyan. The liquid droplets (C) are each discharged.

  The liquid discharge head constituting the recording head 24 includes a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes a phase change due to liquid film boiling using an electrothermal conversion element such as a heating resistor, and a metal due to a temperature change. A shape memory alloy actuator using a phase change, an electrostatic actuator using an electrostatic force, or the like provided as pressure generating means for generating a pressure for discharging a droplet can be used. The carriage 23 can also be mounted with a liquid discharge head that discharges a fixing liquid that reacts with the ink to enhance the fixability of the ink.

  Although not shown, the carriage 23 is provided with a head tank 29 for supplying ink of each color corresponding to each nozzle row Na, Nb of the recording head 24. The head tank 29 is attached to the main body of the apparatus. Ink is supplied from each color ink cartridge (main tank) that is detachably mounted.

  Further, an encoder scale 121 having a predetermined pattern is stretched between the both side plates 101L and 101R along the main scanning direction of the carriage 23, and the carriage 23 is composed of a transmission type photosensor that reads the pattern of the encoder scale 121. An encoder sensor 122 is provided, and the encoder scale 121 and the encoder sensor 122 constitute a linear encoder (main scanning encoder) 123 that detects the movement of the carriage 23.

  A maintenance / recovery mechanism 9 for maintaining and recovering the state of the nozzles 124b of the recording head 24 is disposed in the non-printing area on one side in the scanning direction of the carriage 23. The maintenance / recovery mechanism 9 includes a suction cap 92a and a cap 92b for capping each nozzle surface 124 (see FIG. 3) of the recording head 24 at the frame 90 (referred to as “cap 92” when not distinguished). , A wiper member (wiper blade) 93 for moving the nozzle surface 124 in the direction of the arrow and wiping (wiping) is retained, and preliminary ejection for ejecting liquid droplets that do not contribute to recording in order to discharge the thickened ink ( An empty discharge receiver 94 for receiving droplets when performing (empty discharge) is provided. A suction pump 96 as suction means is connected to the suction cap 92 a, and the suction pump 96 communicates with a waste liquid tank 97. The suction cap 92a is provided with an openable and closable atmospheric release valve 98 that opens the sealed space formed when the nozzle surface of the recording head 24 is capped with the suction cap 92a.

  The paper 10 in the paper feed tray 4 is separated one by one by a paper feed roller (half-moon roller) 43 and a separation pad 44 and fed into the apparatus main body, and conveyed along the conveyance guide member 45 by the conveyance mechanism unit 5. It is fed between the belt 51 and the presser roller 48 and is attracted to the transport belt 51 and transported.

  The conveyance mechanism unit 5 includes an endless conveyance belt 51 that is stretched between a conveyance roller 52 that is a driving roller and a driven roller 53, a charging roller 54 that charges the conveyance belt 51, and the image forming unit 2. And a platen member 55 that maintains the flatness of the conveyor belt 51 at a portion facing the plate.

  The conveyance belt 51 rotates in the belt conveyance direction (sub-scanning direction, paper conveyance direction) when the conveyance roller 52 is rotationally driven by the sub-scanning motor 151 via the timing belt 152 and the timing pulley 153. In this conveyance belt 51, the area from the conveyance roller 52 that adsorbs the paper 10 facing the image forming unit 2 to the driven roller 53 is a normal conveyance portion 51a, and the area from the driven roller 53 to the conveyance roller 52 is reversely conveyed. This is referred to as a portion 51b.

  In addition, a code wheel 154 is attached to the shaft 52 a of the transport roller 52, and an encoder sensor 155 including a transmission type photo sensor for detecting a pattern formed on the code wheel 154 is provided. The code wheel 154 and the encoder sensor 155 A rotary encoder (sub-scanning encoder) 156 that detects the amount and position of movement of the conveyor belt 51 is configured.

  The paper discharge unit 6 includes a paper discharge guide member 61, a paper discharge conveyance roller 62 and a spur 63, and a paper discharge roller 64 and a spur 65. The paper 10 on which an image is formed is discharged to a paper discharge roller 63A and a spur 63B. The paper is discharged face-down onto the paper discharge tray 7 from the middle.

  The reversing unit 8 reverses the paper 10 partially discharged to the paper discharge tray 7 by the switchback method and feeds the paper 10 between the conveyance belt 51 and the presser roller 48. A claw 81, a reverse guide member 82, a reverse roller 83 and a spur 84 as a reverse roller, a conveyance auxiliary roller 85 facing the driven roller 53, a reverse conveyance portion 51b of the conveyance belt 51, and a reverse conveyance of the conveyance belt 51 A detour guide member 86 for guiding the sheet 10 separated from the portion 51 b between the conveyance belt 51 and the pressing roller 48 by detouring the charging roller 54 is provided.

  In this image forming apparatus configured as described above, the paper 10 is separated and fed from the paper feed tray 4 one by one, and the paper 10 is electrostatically attracted to the charged transport belt 51, and the transport belt 51 is moved by the circular movement. The paper 10 is conveyed in the vertical direction. Therefore, by driving the recording head 24 according to the image signal while moving the carriage 23, ink droplets are ejected onto the stopped paper 10 to record one line, and after the paper 10 is conveyed by a predetermined amount, The next line is recorded, and the sheet 10 for which recording has been completed is discharged to the discharge tray 7.

  When performing maintenance and recovery of the nozzles of the recording head 24, the carriage 23 is moved to a position facing the maintenance and recovery mechanism 9 that is the home position, and the suction cap 92a is capped to perform suction and discharge from the nozzles 124b. By performing a maintenance and recovery operation such as nozzle suction and idle ejection for ejecting droplets that do not contribute to image formation, image formation by stable droplet ejection can be performed.

  In the case of performing duplex printing, the first surface printing performs the operation as described above, and when the rear end of the paper 10 passes through the reversing part branch (switching claw 81), the paper discharge roller 64 is driven in reverse. The sheet 10 is switched back, guided to the reversing guide member 82 side, conveyed between the reversing roller 83 and the spur 84, and the sheet 10 is sent between the reverse conveying portion 51 b of the conveying belt 51 and the conveying auxiliary roller 85. It is.

  As a result, the sheet 10 is attracted to the transport belt 51, transported by the circular movement of the transport belt 51, separated from the transport belt 51 on the transport roller 52 side, and guided by the detour guide member 86 (via the detour path). Then, the second side printing is performed by feeding again between the normal conveyance portion 51a of the conveyance belt 51 and the pressing roller 48 and being adsorbed by the conveyance belt 51, and again adsorbed and conveyed to the image forming area by the recording head 24. After that, the paper is discharged to the paper discharge tray 7.

  Next, an outline of the control unit of the image forming apparatus will be described with reference to the block explanatory diagram of FIG.

  The control unit 500 includes a CPU 501 that controls the entire apparatus, various programs including a program that causes the CPU 501 to execute correction control (correction processing) according to the present invention, a ROM 502 that stores other fixed data, image data, and the like. RAM 503 for temporarily storing data, rewritable nonvolatile memory 504 for holding data even while the apparatus is powered off, image processing for performing various signal processing, rearrangement, etc. on image data, and other entire apparatus And an ASIC 505 for processing input / output signals for controlling.

  Also, a print control unit 508 including a data transfer unit for driving and controlling the recording head 24 and a driving signal generating unit, a head driver (driver IC) 509 for driving the recording head 24 provided on the carriage 23 side, A main scanning motor 25 that moves and scans the carriage 23, motor driving units 510 and 511 for driving a sub-scanning motor 151 that moves the conveyor belt 51 in a circular manner, an AC bias supply unit 512 that supplies an AC bias to the charging roller 54, and the like It has.

  The control unit 500 is connected to an operation panel 514 for inputting and displaying information necessary for the apparatus.

  The control unit 500 has an I / F 506 for transmitting and receiving data and signals to and from the host side, an information processing device such as a personal computer, an image reading device such as an image scanner, and an imaging device such as a digital camera. Or the like from the host 600 side via the cable or network.

  The CPU 501 of the control unit 500 reads and analyzes the print data in the reception buffer included in the I / F 506, performs necessary image processing, data rearrangement processing, and the like in the ASIC 505, and prints the image data. The data is transferred from the unit 508 to the head driver 509. Note that generation of dot pattern data for image output can be performed by the printer driver 601 on the host 600 side.

  The print control unit 508 transfers the above-described image data as serial data, and outputs a transfer clock, a latch signal, a control signal, and the like necessary for transferring the image data and confirming the transfer to the head driver 509. Including a D / A converter for D / A converting D / A conversion of drive pulse pattern data stored in the ROM, a voltage signal amplifier, a current amplifier, and the like, and a drive signal or a plurality of drive pulses Is output to the head driver 509.

  The head driver 509 selectively selects a drive pulse that constitutes a drive signal provided from the print control unit 508 based on image data corresponding to one line of the print head 24 that is input serially, and drops droplets of the print head 24. The recording head 24 is driven by applying it to a driving element (for example, a piezoelectric element) that generates energy to be discharged. At this time, by selecting a drive pulse that constitutes a drive signal, for example, droplets having different droplet sizes, such as large droplets, medium droplets, and small droplets, can be ejected and dots having different sizes can be sorted.

  The I / O unit 513 acquires information from the main scanning encoder 123, the sub-scanning encoder 156, and various sensor groups 515 mounted on the apparatus, extracts information necessary for controlling the printer, and print control unit 508. Also used to control the motor drive units 510 and 511 and the AC bias supply unit 511. The sensor group 515 includes an optical sensor (paper sensor) 521 provided on the carriage 23 for detecting the position of the paper, a thermistor for monitoring the temperature and humidity in the machine, a sensor for monitoring the voltage of the charging belt, and a cover. The I / O unit 513 can process various sensor information.

  For example, the CPU 501 detects a speed detection value and a position detection value obtained by sampling a detection pulse from the encoder sensor 122 constituting the main scanning encoder 123, and a speed target value and a position target obtained from a previously stored speed / position profile. The drive output value (control value) for the main scanning motor 25 is calculated based on the value and the main scanning motor 25 is driven via the motor driving unit 210. Similarly, a speed detection value and a position detection value obtained by sampling a detection pulse from the encoder sensor 155 constituting the sub-scanning encoder 156, a speed target value and a position target value obtained from a previously stored speed / position profile, and Based on this, a drive output value (control value) for the sub-scanning motor 151 is calculated, and the sub-scanning motor 151 is driven via the motor driving unit 211.

  Further, the control unit 500 drives and controls the cap moving mechanism 531 that moves the cap 92 forward and backward with respect to the nozzle surface of the recording head 24 via the maintenance / recovery driving unit 534, and the wiper moving mechanism 532 that moves the wiper member 94. And the supply pump 13, the suction pump 96, and the air release valve 98 are controlled to perform ink supply control and maintenance / recovery operation control.

  Next, an example of an environment in which the image forming apparatus according to the present invention is used will be described with reference to FIG.

  In this example, a color scanner (hereinafter abbreviated as “scanner”) 1001, a personal computer (PC) 1002, a color printer 1003 that is an image forming apparatus according to the present invention, and the like are connected to a network 1004.

  When requesting color printing from the PC 1002 to the printer 1003, the request image 1005 includes, for example, an image read from the scanner 1001, an image acquired from the network 1004 (for example, the Internet), and an image created by the PC 1002. In response to a print request from the PC 1002, the printer 1003 outputs a print output 1006.

  Next, transfer of print data between the host and the image forming apparatus will be described with reference to FIG.

  Here, the print data created by the print data creation unit 1020 configured by the printer driver 601 on the host 600 side such as the PC 1002 is transferred to the printing unit 1028 configured by the control unit 500 on the image forming apparatus side.

  First, a status request is sent from the print data creation unit 1020 to the printing unit 1028, and a status response is returned from the printing unit 1028. Thereby, the state of the printing unit 1028 can be known.

  If there is no print disable factor or the like, the print data creation unit 1020 issues a print request, and notifies the print unit 10228 printing permission in response thereto. This notification is not necessary.

  Thereafter, the print data creation unit 1020 transfers the print data, and the print unit 1028 notifies the result.

  Next, the print processing unit 1107 that handles print data on the printing unit 1028 side will be described with reference to FIG.

  Here, the print data 1105 is K (black) when it is binary (monochrome), and C (cyan), M (magenta), and Y (yellow) gradation data when it is color. .

  The print processing unit 1107 receives the print data 1105 by the print data receiving unit 1108. For monochrome printing, the print data analysis unit 1109 extracts K gradation data from the print data 1105 for each pixel and notifies the K print control unit 114 of it. For color printing, CMY gradation data is extracted for each pixel from the print data 1105 and notified to the CMY print controllers 1111, 1112, and 1113.

  Each of the CMYK print control units 1111 to 1114 controls the printing of each pixel corresponding to the notified density by causing the engine control unit 110 to drive and control the print mechanism unit (engine).

  The first error holding unit 115 holds apparatus-specific transport error information. The conveyance error unique to the apparatus is information relating to a variation error between apparatuses (referred to as “first error”) in the manufacturing stage.

  In the second error holding unit 116, an error of an actual writing position (actual landing position) with respect to a target writing position (target landing position) of a pixel by performing vertical conveyance printing (this is called a “second error”, Details will be described later).

  The engine control unit 1110 reads out the first error information held in the first error holding unit 1115 and the second error information held in the second error holding unit 1116 when driving the print mechanism unit. The sheet conveyance timing is controlled.

  Each unit of the print processing unit 1107 is configured by the control unit 500 described above. The first error and the second error are stored in advance in storage means such as a ROM or VRAM, or are directly written in the program.

  Here, the shapes of pixels formed by vertical printing (horizontal conveyance printing) and pixels formed by horizontal printing (vertical conveyance printing) will be described with reference to FIG.

  First, in FIG. 8, the main scanning direction (driving direction) is expressed as a line, and three pixels corresponding to three lines of N line, N + 1 line, and N + 2 line are shown in the printing order in the paper conveyance direction.

  Here, in FIG. 8A, in the vertical hit example, the N line has no print pixels in the vicinity (dots in all three pixels = no landing droplets), the next line N + 1 has dots in two pixels, and the next line N + 2 Then, it is assumed that all three pixels have dots.

  Further, in FIG. 8B, in the horizontal hit example, the N line has dots in one pixel, the next line N + 1 has dots in two pixels, and the next line N + 2 has dots in all three pixels.

  As can be seen from FIG. 8, in vertical printing (horizontal conveyance printing), since the recording medium is conveyed horizontally, the dots (pixels) formed when the droplets land from above are almost perfect circles. Become. When the head is continuously driven, the vector direction of the dots is slightly longer in the drive direction and the transport direction.

  On the other hand, in horizontal printing (vertical transport printing), since the recording medium is transported vertically, gravity is applied to the liquid droplets in order to discharge and land the liquid droplets in the horizontal direction. Dots (pixels) have an elliptical shape that is long in the vertical direction.

  As a result, in horizontal printing (vertical conveyance printing), there are more overlapping portions of the pixels of the lines preceding and following in the conveyance direction than in vertical printing (horizontal conveyance printing). For this reason, in particular, an image in which the gradation of the light color is recognized darker than actual is obtained.

  Next, the landing position error in horizontal printing (vertical conveyance printing) will be described with reference to FIG.

  FIG. 9A is an ideal pixel (dot) that is assumed to be unaffected by gravity during vertical printing, and FIG. 9B is an elliptical shape in which the upper portion is lowered downward in the vertical direction by Δ1 due to the influence of gravity. FIG. 10C shows an elliptical pixel that can be compared with the ideal pixel of FIG. 10A by raising the elliptical pixel of FIG. 10B upward by Δ1 in the vertical direction. ing.

  Here, r1 represents an ideal pixel radius, and r2 represents a distance from the center of the longest part of the ellipse. Δ2 is the difference between the center positions of the circle and the ellipse, and Δ3 is the difference between the diameter of the circle and the distance in the longitudinal direction of the ellipse. As a result, the pixel writing (position) error in vertical transport printing is (Δ4 = Δ1 + Δ2).

  Next, the conveyance control in the first embodiment of the present invention will be described with reference to the flowchart of FIG.

  Printing is started upon receipt of a print request. At this time, the conveyance start determination process of FIG. 10 is performed to control the conveyance of the paper. Here, the first error is read out, the second error is read out, and the sheet conveyance start timing is determined from these first and second errors. Although not shown, the conveyance is started at the determined conveyance start timing.

  In this case, since the first error is an error due to apparatus variation, the first error is an error that is swung upstream or downstream in the paper transport direction. On the other hand, the second error is necessarily an error that is shifted backward (upstream in the sheet conveyance direction, that is, the direction in which the leading margin is enlarged), and therefore the conveyance start timing is corrected to be downstream in the sheet conveyance direction.

  As a result, the image quality of an image formed by horizontal strike can be improved, and printing can be performed at an optimum position.

  Next, conveyance control in the second embodiment of the present invention will be described with reference to the flowchart of FIG.

  In the present embodiment, the second error for monochrome printing and the second error for color printing are held separately.

  Then, after reading the first error, it is determined whether or not color printing is performed. If color printing is performed, the second error for color printing is read to determine the conveyance start timing. In the case of monochrome printing, the second error for monochrome printing is read and the conveyance start timing is determined. Thereafter, although not shown, the conveyance is started at the determined conveyance start timing.

  As a result, images can be printed at optimum positions on the paper separately for monochrome printing and color printing.

  Next, the second error determination (determination) process according to the third embodiment of the present invention will be described with reference to the flowcharts of FIGS.

  In the present embodiment, pixel writing (position) errors (this is referred to as “the value”) are held for K, C, M, and Y as the second errors. This error is assumed to be obtained by experimental results or logical calculation.

  Then, as shown in FIG. 12, in the monochrome printing error determination (determination) process, the value of K is read to determine the second error for monochrome printing. If the value for monochrome printing is held as the second error, the read value is used as the second error.

  As shown in FIG. 13, in the color printing error determination (determination) process, the respective values of C, M, and Y are read to determine the second error for color printing. The determination of the second error is, for example, by calculating an average value of the respective values of C, M, and Y, or by searching for a minimum value or a maximum value in each of the values to determine the second error for color printing. And

  As a result, it is possible to correct the print start position in consideration of the error specific to vertical printing for each color in color printing.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. 12 and FIG.

  Since the ink of each color has different ejection characteristics depending on the viscosity, the viscosity is used here as “the value” in the third embodiment.

  Then, in the monochrome printing error determination (determination) process, the value of K = viscosity is read to determine the second error for monochrome printing.

  In the error determination (determination) process for color printing, each value of C, M, and Y = viscosity is read to determine the second error for color printing. The determination of the second error is, for example, by calculating an error corresponding to each viscosity of C, M, and Y and then calculating an average value of the calculated errors of C, M, and Y, or The minimum value or the maximum value is searched for as the second error for color printing.

  As a result, it is possible to correct the print start position based on an error inherent to vertical transport printing in accordance with an error that takes into account the viscosity of the liquid to be discharged.

  Next, a fifth embodiment of the present invention will be described with reference to FIG.

  This embodiment is an example in which the second error (including the value and viscosity) described in the above embodiments for adjusting the print start position by operating the operation panel of the apparatus can be input.

  Referring to FIG. 14, utility purpose menus are sequentially displayed by pressing the cursor key “↓” (S1501 to 1506). Here, the target print position adjustment is displayed in S1502. At this time, it is assumed that the “→” key is pushed down one level down, and the “←” key goes up one level (= return). In the lower hierarchy, each ink can be selected. Here, it is assumed that the initial value of the print position adjustment amount is “0.00”.

  In this example, the state when K (black) is selected in S1503, the numeric keys “2” and “5” are input, and then the “OK” key is input and the second error is input “0.25”. Is shown.

  Other colors can be input in the same manner. The input value is held in an internal storage unit (holding unit).

  Thereby, the value of the second error can be input from the apparatus.

  Next, a sixth embodiment of the present invention will be described with reference to FIG.

  The present embodiment is an example in which the second error value can be input on the host side to which the image forming apparatus is connected.

  With reference to FIG. 6 described above, for example, printing conditions (size, paper direction, single-sided or double-sided, aggregation, etc.) can be indicated in the print request. This print condition can be set, for example, on the print property screen shown in FIG.

  Referring to FIG. 15, when the print position adjustment 1101 is pressed as shown in FIG. 15A, a pop-up 1102 as shown in FIG. 15B is opened, and one of the B (= K) CMY inks is displayed. Adjustment amount can be set.

  This set value can be notified to the print requesting device (host side) of the current device by a status response. In this case, in FIG. 15 (b), the value received on the host side may be displayed and changed as necessary.

  In any case, the adjustment result of the print start position can be instructed to the image forming apparatus side by a print request.

  Next, a seventh embodiment of the present invention will be described.

  An erroneous setting may be made in the fifth and sixth embodiments described above. Therefore, in the environment described with reference to FIG. 5, for example, the PC 1002 serving as the host can acquire a driver of a required printer 1003 connected to the network 1004 through the network 1004. When the driver is acquired, the initial value of the print adjustment value is also acquired.

  As a result, even if there is no setting menu on the host side, at least an initial value can be updated by a print request to the image forming apparatus. For example, the providing side may prepare a driver according to the type of ink.

  Next, FFO will be described with reference to FIGS.

  FIG. 16 shows an example of an image forming apparatus of a vertical printing method (horizontal conveyance printing). Paper is fed from the paper feed tray 2001 by the paper feed roller 2002, the paper 2000 is conveyed in the horizontal direction, and the image forming unit 2003 discharges droplets downward in the vertical direction to form an image. The paper is discharged from a paper discharge tray 2005.

  Here, the upper cover 2010 and the front cover 2011 are provided to be openable and closable.

  Therefore, the jam removal is performed by opening the upper cover 2010 and the front cover 2011. Further, the upper cover 2010 can be widely opened, so that the ink cartridge can be replaced from the direction of the arrow A. Further, for example, when the paper feeding unit is opened, it can be released by reducing the pressure between the pair of paper feeding rollers 2002. Also. It is assumed that a jam in the middle of conveyance can be removed from the left of the image forming unit 2003. It is assumed that the front cover 2011 can remove the jam of the paper discharge unit by reducing the pressure between the pair of paper discharge rollers 2004 by opening the paper discharge tray 2005 little with little interlocking.

  In other words, in an image forming apparatus for horizontal conveyance printing, a recording head is disposed on the upper part of the apparatus main body, so that it is difficult to remove jam by only opening and closing one cover.

  FIG. 17 shows an example of an image forming apparatus of a horizontal printing method (vertical conveyance printing). The paper 2000 is separated from the paper feed tray 2021 in the horizontal direction and fed via a pair of paper feed rollers 2022. While the paper 2000 is being conveyed in the vertical direction, the image forming unit 2023 ejects liquid droplets in the horizontal direction to form an image, and the paper is discharged onto the paper discharge tray 2025 via the pair of paper discharge rollers 2024. .

  The front cover 2031 is provided so that it can be opened and closed.

  Here, the jam removal is performed by opening the front cover 2031. Further, the ink cartridge can be exchanged from the direction of arrow B by widely opening the front cover 2031. Further, the pressure between the paper feed rollers 2022 and the paper discharge rollers 2024 can be reduced, or the paper raising mechanism of the paper feed tray 2021 can be released.

  As described above, in the horizontal conveyance printing image forming apparatus, various jams can be removed by opening the front cover on the front side of the apparatus.

  In the present application, the “paper” is not limited to paper, but includes OHP, cloth, glass, a substrate, etc., and means a material to which ink droplets or other liquids can be attached. , Recording media, recording paper, recording paper, and the like. In addition, image formation, recording, printing, printing, and printing are all synonymous.

  The “image forming apparatus” means an apparatus that forms an image by discharging liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. “Formation” means not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium (simply causing a droplet to land on the medium). ) Also means.

  The “ink” is not limited to an ink unless otherwise specified, but includes any liquid that can form an image, such as a recording liquid, a fixing processing liquid, or a liquid. Used generically, for example, includes DNA samples, resists, pattern materials, resins, and the like.

  In addition, the “image” is not limited to a planar image, and includes an image given to a three-dimensionally formed image and an image formed by three-dimensionally modeling a solid itself.

  Further, the image forming apparatus includes both a serial type image forming apparatus and a line type image forming apparatus, unless otherwise limited.

2 Image forming unit 4 Paper feeding unit 5 Conveying mechanism 6 Paper discharge unit 7 Paper discharge tray 8 Reversing unit 9 Maintenance recovery mechanism 10 Paper (recording medium)
23 Carriage 24 Recording head 29 Head tank 51 Conveying belt 500 Control unit 1107 Print processing unit 1109 Print data analysis unit 1116 Second error holding unit

Claims (4)

In an image forming apparatus that forms an image by ejecting liquid droplets from a recording head in a horizontal direction on a recording medium conveyed in the vertical direction.
Holding means for holding information on an error between the actual landing position when the droplet discharged from the recording head is affected by the gravity with respect to the target landing position when the droplet is not affected by gravity;
An image forming apparatus comprising: means for controlling a feeding timing of the recording medium in accordance with information on an error held in the holding means.   The image forming apparatus according to claim 1, wherein the holding unit holds information relating to an error for monochrome printing and information relating to an error for color printing. The holding means holds information regarding errors for each color used in color printing,
3. The image forming apparatus according to claim 1, wherein the control unit determines an error to be used by calculating an average value, a minimum value, or a maximum value from information on the error for each color. The holding means holds information about the viscosity of the liquid to be discharged,
The image forming apparatus according to claim 1, wherein the control unit determines the second error from information on a viscosity of the liquid to be discharged.

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